THESIS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY

Air Pollution from Ships

Emission Measurements and Impact Assessments

HULDA WINNES

Department of Shipping and Marine Technology CHALMERS UNIVERSITY OF TECHNOLOGY

Gothenburg, Sweden 2010

Air Pollution from Ships Emission Measurements and Impact Assessments HULDA WINNES ISBN 978-91-7385-420-7 © HULDA WINNES, 2010. Doktorsavhandlingar vid Chalmers tekniska högskola Ny serie nr 3101 ISSN 0346-718X Department of Shipping and Marine Technology Chalmers University of Technology SE-412 96 Gothenburg Sweden Telephone + 46 (0)31-772 1000 Cover: Ship funnel, www. iStockphoto.com Chalmers Reproservice Gothenburg, Sweden 2010

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Air Pollution from Ships - Emission Measurements and Impact Assessments HULDA WINNES Department of Shipping and Marine Technology Chalmers University of Technology ABSTRACT Environmental impact and air pollution from ships have received increasing attention the last decades. Due to combustion characteristics of typical marine engines and a wide-spread use of unrefined fuel, the global fleet emits significant amounts of SO2, NOX

In order to assess the impacts caused by ship emissions to air, infor-mation on ships’ activities in an area or the corresponding fuel use is essen-tial. In combination with an emission factor that state the mass of an emitted pollutant related to either the work produced by ship engines or the mass of combusted fuel, the total emitted mass of a pollutant is established.

and particles to air. Impact assess-ments and information on emitted amounts are important inputs to decision-making in regulation development and also for ship designers who aim at environmentally improved designs.

Ship engines are diverse and the emission factors are insufficiently quantified for certain operational modes and specific pollutants which makes assessments difficult. Measurements on-board ships were thus conducted in order to determine emission characteristics during manoeuvring periods and for engines operating on fuels of different qualities. The measurement studies comprised three engines and focussed on emissions of particles and NOX

Elevated levels of numbers of small particles (0.30-0.40µm) were observed during manoeuvring periods and from combustion of marine distillate oils. Sizes <0.30µm were not covered by the study. The size distri-bution of particles is potentially important in impact assessments since there are indications that fine and ultrafine particles are associated with higher health risks than coarse particles. The particle mass was reduced by half from a shift from a heavy fuel oil with 1.6% sulphur content to a marine gasoil with 0.03% sulphur.

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The results from the impact assessments point in favour of the abate-ment technologies selective catalytic reduction (SCR), shore side electricity (SSE) connection and the use of fuel with low sulphur content in a local and regional cost benefit perspective. The SSE seemed beneficial also from a ship-owner perspective. SCR was also analysed in a life cycle perspective and it was concluded there were overall benefits from its use for all impact categories except global warming.

Keywords: air pollution, ship emissions, manoeuvring ships, impact

assessment, emission measurement, fuel, abatement, ships, emission inventory

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LIST OF PUBLICATIONS This thesis is based on the work contained in the following papers:

Paper I: Winnes, H. and Fridell, E.

Particle emissions from ships: dependence on fuel type Journal of the Air and Waste Management Association (2009) 59:1391-1398

Paper II: Winnes, H. and Fridell, E. Emissions of NOX

Transportation Research Part D: Transport and Environment (2010) 15(4): 204-211

and particles from manoeuvring ships

Paper III: Andersson, K. and Winnes, H.

Environmental trade-offs in nitrogen oxide removal from ship engine exhausts. Submitted to the Journal of Engineering for the Maritime Environment Proceedings of the IMechE Part M

Paper IV: Winnes, H., Fridell, E, Åström, S. and Andersson, K.

Improved air quality and associated costs from regulations on ship emissions - case study on the Port of Gothenburg. In manuscript

Paper V: Winnes, H. and Ulfvarson A. Environmental improvements in ship design by the use of scoring functions Journal of Engineering for the Maritime Environment Proceedings of the IMechE Part M, (2006) 220(M1): 29-41

Distribution of work: Paper I and II were planned by both authors. The measurements were conducted by experienced measurement technicians from IVL together with H. Winnes. Emission factors were calculated by E. Fridell. Analysis and writing were done by H. Winnes in discussion with E. Fridell. The research and writing of Paper III were carried out by K. Andersson in discussion with H. Winnes. The emission inventory in Paper IV was conducted by H. Winnes. Economical calculations in the same paper were conducted by S. Åström. The planning, analysis of results and writing were mainly done by H. Winnes in discussion with E. Fridell, K. Andersson and S. Åström. The planning, research activities and writing of Paper V were done by H. Winnes in discussion with A. Ulfvarson. A. Ulfvarson conducted the mathematical analysis.

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TABLE OF CONTENTS 1 INTRODUCTION ..................................................................................................................................................................... 1

1.1 RATIONALE FOR THE CHOICE OF RESEARCH AREA ................................................................................................ 3

1.1.1 Overview of impacts of air pollution caused by ships .............................................................................. 4

1.1.2 Absolute and relative amounts ....................................................................................................................... 8

1.2 AIM AND RESEARCH QUESTIONS ........................................................................................................................... 10

1.3 METHODOLOGICAL APPROACH AND SCIENTIFIC FOUNDATION .......................................................................... 11

1.4 FRAME OF REFERENCE ............................................................................................................................................ 14

2 SHIP ENGINES, FUELS AND POLLUTANT FORMATION ............................................................................ 19

2.1 SULPHUR IN FUEL AND SO2 .................................................................................................................................. 22

2.2 NITROGEN OXIDE EMISSIONS FROM SHIPS .......................................................................................................... 22

2.3 PARTICLES FROM COMBUSTION IN MARINE ENGINES .......................................................................................... 24

2.3.1 Particle composition ....................................................................................................................................... 26

3 QUANTIFICATION OF AIR POLLUTION FROM SHIPS .................................................................................. 29

3.1 EMISSION INVENTORIES .......................................................................................................................................... 30

3.1.1 Emission factors .............................................................................................................................................. 31

3.1.2 Within the ship plumes .................................................................................................................................. 36

3.2 CONSIDERATIONS IN LOCAL INVENTORIES ........................................................................................................... 38

4 EVALUATION OF ENVIRONMENTAL IMPACTS ................................................................................................ 41

5 TECHNOLOGICAL IMPROVEMENT POTENTIALS ........................................................................................... 45

5.1 LIMITATIONS DUE TO THE SHIP DESIGN PROCESS ............................................................................................... 45

5.2 TECHNOLOGICAL IMPROVEMENTS ........................................................................................................................ 46

6 THE REGULATORY FRAMEWORK ............................................................................................................................ 51

6.1 INTERNATIONAL REGULATIONS .............................................................................................................................. 52

6.2 EU REGULATIONS .................................................................................................................................................... 54

6.3 NATIONAL REGULATIVE MEASURES AND ECONOMIC INCENTIVES ...................................................................... 55

7 PRESENTATION OF STUDIES: DESCRIPTIONS OF METHODS AND RESULTS .......................... 57

7.1 MEASUREMENT STUDIES ........................................................................................................................................ 57

7.1.1 Fuel shift study ................................................................................................................................................ 59

7.1.2 Manoeuvring study ......................................................................................................................................... 60

7.2 IMPACT ASSESSMENT STUDY OF UREA FOR SCRS ON SHIPS ........................................................................... 61

7.3 COST BENEFIT ANALYSIS (CBA) STUDY ............................................................................................................... 62

7.4 SHIP DESIGN METHODOLOGY STUDY ................................................................................................................... 64

8 PUTTING THE PIECES TOGETHER – ANALYSIS AND CONCLUSIONS ............................................ 67

9 FURTHER WORK ................................................................................................................................................................ 73

REFERENCES ................................................................................................................................................................................. 75

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ACKNOWLEDGEMENTS

This work has been financed by The Swedish Governmental Agency for Innovation Systems (Vinnova), the Intermodeship project within the European 5th RTD Framework Programme for Land Transport and Marine Technologies, Hugo Heymans forskningsfond and Chalmersska forskningsfonden.

I would like to thank my supervisors Associate Professor Sven Lyngfelt, Associate Professor Karin Andersson and Adjunct Professor Erik Fridell for scientific support and guidance during the work on this thesis.

Professor Anders Ulfvarson and Adjunct Professor Herbert Nilsson were my supervisors the first years of my PhD studies and gave me an introduction to the world of shipping and ship design that I will always value.

I would also like to thank:

Tärntank Rederi AB and the ferry company who made the emission measurement studies possible. The Masters, Chief engineers and their crew onboard Tarnbris and the ferry are also greatly thanked, their efforts in connection with the measurements were absolutely essential for successful results. Kjell Peterson and Erica Steen at the Swedish Environmental Re-search Institute IVL, who conducted emission measurements onboard with great skill despite the waves. Åsa Wilske, Environmental Manager at the port of Gothenburg and Maria Holmes at the City of Gothenburg for their help in connection to the emission inventory. Dr Ida-Maja Karle who has been there whenever I have needed advice, support or just someone to talk to. friends and colleagues at the department who has helped me by answering my many questions or simply by giving me something else to think about for a few moments. my lovely family ♥.

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1 INTRODUCTION

As part of the great system of nature, human actions inevitably

influence the environment. Air pollution has been a problem in

different forms for centuries. Problems with the London sulphurous

smog were documented by the Englishman John Evelyn already in the

17th

Health problems caused by air pollution can be severe, and thus

many cities around the world monitor a set of criteria pollutants that

informs them of peak concentrations and average ambient levels of

these harmful pollutants. Generally, ceiling values that should not be

exceeded more than a specified number of instances per year

accompany those monitoring schemes. Evelyn wrote about sulphur

and soot in 1661, and these pollutants still constitute a significant part

of the air pollution problem. Typical criteria pollutant species related

to health issues are particulate matter (PM), nitrogen oxides (NO

century, at which time the domestic use of high-sulphur coal was

common: ‘…no sooner [the visitors] enter into it [London], but they

find a universal alteration in their Bodies, which are either dryed up or

enflamed …”, as he wrote in his work Fumifugium (1661, reprinted in

1999).

X),

sulphur dioxide (SO2), ozone (O3

The contribution to air pollution by airborne emissions from ships

was brought to scientific attention during the 1990s, and the literature

on related subjects rapidly increased during the beginning of the 21

), carbon monoxide (CO), a set of

heavy metals and possibly some hydrocarbon species. In addition to

the health effects they cause, these pollutants also contribute to

acidification, eutrophication and damage to crops.

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century. Figure 1 gives an indication of this increased awareness by

showing the rise in the number of published articles within the area in

the scientific literature database ISI web of knowledge.

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Figure 1. Count of search results for the search string emissions AND ships

in the ISI web of knowledge collection of databases. No hits before 1991.

The International Maritime Organization (IMO) is a UN agency with

a central position for the regulations of air pollution from ships. IMO

has 169 member governments that works to develop and adopt new

international regulations on different maritime topics, primarily safety,

security and pollution prevention. The first rules for regulations to

limit airborne emissions from international shipping resulted from the

entry into force of the Annex VI of the International Convention for

the Prevention of Pollution from Ships (MARPOL) in May 2005.

MARPOL was adopted in its first state in 1973 by the IMO. The

Annex VI to the convention regulates several pollutants, including

NOX from newly built ships, and SOX. Certain maritime regions are

designated emission control areas (ECAs) where the regulated

emission levels are lower than in the rest of the ocean. Accordingly,

regulations of air pollution from ships are only effective for certain

aspects of the present shipping activities. The regulations will become

tighter in a stepwise manner and additionally, the number of emission

control areas will potentially increase.

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Shipping has an essential role in the global transport system. One

estimate claims that the shipping industry carries more than 80% of

the total volume of transported goods in the world (Asariotis et al.

2009). The amount of goods in sea borne trade has grown throughout

the last century, and from 1970 to 2008 the increase was more than

threefold (Wijnolst et al. 1997; Asariotis et al. 2009). Also, the average

ship size has increased; the average age of a ship was 23 years in 2009

while the average age of a dead weight ton (DWT) of the same fleet

was 14 years. Another characteristic of the world fleet is that the

amount containerised goods has increased more than other types of

goods (Asariotis et al. 2009).

Different ship types, such as roll-on/roll-off ships, dry and liquid

bulk carriers, and passenger ferries, will differ in several design aspects

in order to fulfil the logistical requirements for a particular cargo type

or for passenger transport. A few obvious examples of differing

designs include the shape of the cargo space and the cargo handling

equipment, but differences could also be related to the value of the

cargo, for example, because it is desirable to transport valuable goods

quickly, which requires powerful engines. Typically, containerised

goods are generally on the high end regarding value, and bulk goods

are on the low end.

An increasing fleet with large engines will without technological

changes require more fuel and cause more pollution. The regulative

measures are incentives to implement existing technologies abating

airborne emissions and counteract an increasing environmental impact

from a growing fleet. Several technological options exist for the

abatement of CO2, NOX and SO2

1.1 RATIONALE FOR THE CHOICE OF RESEARCH AREA

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Today’s society depends heavily on a functioning transport system.

Compared to other transport modes, sea transport typically consumes

the least fuel oil per ton-km (Michaelowa and Krause 2000).

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The work presented in this thesis contains characterisations of

emissions from ships and assessments of subsequent environmental

impacts. Although the utility of the transport is seldom mentioned in

the following text, and even though it is difficult to present definite

and intelligible figures of this utility, it should be kept in mind.

1.1.1 OVERVIEW OF IMPACTS OF AIR POLLUTION CAUSED BY

SHIPS

The previously mentioned pollutants, NOX, particles, ozone, SO2, and

CO2

Table 1

, all of which are products of combustion of fuel oil, can be

classified as either primary or secondary pollutants. ‘Primary

pollutants’ is a term used for the pollutants that are formed during the

actual combustion process, while ‘secondary pollutants’ are formed in

the atmosphere as a consequence of chemical reactions involving the

primary species. The potential impact categories influenced by air

pollution from oil combustion are health problems, acidification,

eutrophication, photo-oxidant formation and climate change, to name

the most important (Jackson and Jackson 1996). An overview of these

pollutants and their corresponding impact categories is presented in

.

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Table 1. Primary pollutants from the combustion of oil and their major

potential impacts.

Pollutant

Impact categories Particles SO NO2 COX HC 2 CO

Health effects X X X X

Acidification X X

Photo-oxidant formation

X X

Eutrophication X

Climate change X X(CH4 )

Health risks

Several of the primary and secondary air pollutants from fuel

combustion cause health problems. The correlation between adverse

health effects and particulate matter is well established, and ozone,

SO2 and NO2

Particulate matter is a heterogeneous group that can be divided into

subgroups based on characteristics that are believed to determine

health risks: particle surface area, particle size, elemental composition,

composition of organic compounds are supposed to be more important

than particle mass for determining associated health risks (Lighty et al.

2000; World Health Organization 2006). Which properties that involve

most health risks are not fully understood. Several epidemiological

studies, however, suggest elevated mortality risks are correlated to the

concentrations of particles and some of them indicate that fine

particles are more harmful than coarse particles (Pope and Dockery

2006). In addition to the mortality risks, there are several different

types of health risks including cardiovascular diseases and respiratory

have also been shown to alter lung function (World

Health Organization 2006).

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failure. It is the ultrafine particles that primarily have been observed

to cause damage to other parts of the body than the lungs (Pope and

Dockery 2006). In 2007, Corbett et al. reported that, globally, up to

64,000 premature deaths per year could be attributed to emissions of

PM2.51

Acidification

from ships in 2002, and that number is predicted to increase to

91,000 by 2012 (Corbett et al. 2007).

When sulphates or nitrates are abundant in aerosol particles, these

particles become acidic and precipitate as acid rain. Acidification is

tightly coupled to H2SO4 and HNO3, which are formed by the

oxidation of SO2 and NO2 (Finlayson-Pitts and Pitts 2000). The

associated environmental impacts range from effects from wear on

buildings and materials to the release of metal ions from lake

sediments, altering the life of water living species and ultimately

leading to fish death (see e.g. (Ottar 1986)). Dalsøren et al. (2009)

show that shipping contributes to 25-50% of NO3

Eutrophication

wet deposition and

15-25% of sulphur deposition in northwestern North Western North

America and Scandinavia. Another study considering acid deposition

in Europe due to shipping indicates that the effects are most

significant in the area around southern Scandinavia and the English

channel (Derwent et al. 2005).

Nitrogen oxides are also involved in the eutrophication issue.

Eutrophication is a problem associated with elevated levels of plant

nutrients such as nitrogen and phosphor in waters and soils. Excess

growth of certain nutrient-loving species occurs at the expense of

others. In sea areas, algal blooms are typical examples related to

eutrophication. The Baltic Sea has episodes of ‘blooms’ of

1 Particulate matter (PM) is often categorized by the aerodynamic

diameter of particles. PM2.5 comprises all particles of <2.5µm diameter

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cyanobacteria in the summertime, which ultimately causes oxygen

depletion at the sea floor when dead organic material is decomposed

(Jackson and Jackson 1996). A Finnish project concluded that at

certain locations in the Baltic Sea, 25% of the nitrogen load originated

from atmospheric deposition, and half of that could be attributed to

ships’ emissions of NOX

Photo-oxidant formation

(Stipa et al. 2007).

Photo-oxidant, or photochemical oxidants is a term used for

atmospheric oxidants that are formed by photo-chemically induced

processes of volatile organic carbons (VOC) and CO. Typically, the

most important species is O3

In the presence of sunlight, VOC and NO

(Kley et al. 1999).

X can lead to a net

formation of O3. High O3

Ships emissions of NO

concentration are typical of smog incidents,

a phenomenon first described in the 50ies (Haagen-Smit 1952). The

damages caused are eye and lung irritation and damage to crops (Kley

et al. 1999).

X

Climate change

were reported by Lawrence and Crutzen

(1999) to double the ozone formation over the open oceans. The effect

is however less obvious in coastal areas (Lawrence and Crutzen 1999;

Endresen et al. 2003).

Shipping also contributes to the build up of gases that are believed to

affect the climate of the earth. Certain mechanisms lead to higher

atmospheric temperatures while other will reflect the incoming solar

light and cool the atmosphere. CO2 is an important warming gas and

CO2 emissions from ships increase due to increased transport

activities. Other, more potent, climate gases are methane (CH4) and

nitrous oxide (N2O), which are emitted from ships in minor amounts

(Cooper 2001; Cooper and Gustavsson 2004) and the secondary

pollutant ozone. Emissions of particles and SO2, which forms

sulphate-containing particles, contribute to cloud formation that

probably has a negative impact on the radiative forcing of the earth

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(Seinfeld and Pandis 2006). The sulphate particles also reflect

incoming solar light directly (Finlayson-Pitts and Pitts 2000). The

radiative forcing capacity is often presented in terms of global

warming potential (GWP). As the involved chemical species have

different decay rates in the atmosphere, the value on GWP is

integrated over time in order to account for changes in atmospheric

chemical composition. The net effect of ship emissions on radiative

forcing has been estimated to be negative in a short term perspective

despite CO2 and O3 production (Lee et al. 2006; Eyring et al. 2007;

Lauer et al. 2007), though the warming effects of CO2

1.1.2 ABSOLUTE AND RELATIVE AMOUNTS

will be

dominant in a long term perspective (Buhaug et al. 2009).

The reason that ships are large emitters of certain polluting

compounds can technologically be explained by combustion and fuel

characteristics. The use of fossil fuels in marine engines has dominated

since the beginning of the 20th

As the fuel oil is combusted, a variety of pollutant species is

dispersed into the air. Typical exhausts from ships contain high levels

century (Wijnolst 1995). Most ships in

the world fleet are equipped with large diesel engines for propulsion

and electricity production. Recent extensive inventories have

estimated the fuel consumption of the global fleet for different years

during the first decade of this century (Corbett and Koehler 2003;

Endresen et al. 2003; Eyring et al. 2005; Endresen et al. 2007; Buhaug

et al. 2009; Dalsøren et al. 2009; Paxian et al. 2010). The lowest

estimate of 158 million tonnes refers to the year 2000 (Endresen et al.

2003), and the highest estimate, 333 million tonnes refers to the year

2007 (Buhaug et al. 2009). Differences in the scope of the inventories,

i.e. which ships that are included, account for some of the differences

in these inventory results. An estimate for the fuel consumption for

road-based transport from Borken et al. (2007) is 1,448 million tonnes

per year (year 2000).

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of SO2, particles and NOX

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Fuel consumption

CO2 NOX SO2 PM

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Road transport (Borken et al, 2007) base year 2000

Marine transport (Corbett and Koehler, 2003) base year 2001

Marine transport (IMO 2nd GHG study, 2009) year 2007 (int'l shipping)

Marine transport (Dalsøren et al, 2009) base year 2004

Marine transport (Paxian et al, 2010) year 2006

. Estimates of total global emissions of

selected pollutants from ships from four different studies are

compared to emissions from road transport in Figure 2.

Figure 2. Relative global yearly emissions from road transport and marine

transport. The emissions from road transport in million tonnes/year are

indicated above the respective bars; road transport = 1. Note that no

adjustments of transport demand changes between the years have been

made.

As can be seen in Figure 2, the annual fuel consumption used for

marine transport is substantially less than that of road transport. The

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amount of SO2 from marine transport is considerably higher than SO2

from road transport, while the picture is not as clear for PM. The NOX

The global inventories on emitted amounts expose ships’ relatively

large contributions of NO

emissions are higher per unit of fuel but with a lower total.

X, SO2

and PM. This is partly a result of the

differences in environmental regulations concerning the different

transport modes along with a set of technological differences.

1.2 AIM AND RESEARCH QUESTIONS

The aim of this thesis is to quantify negative environmental effects on

a local scale caused by airborne emissions from ships and to evaluate

results of technological as well as political measures of improvement.

Most of the reasoning here is applicable in a global perspective as

the discussed pollutants are transported in the atmosphere over long

distances.

In order to acquire results relevant to reach this aim, several more

specific objectives are pursued. The following research questions cover

these objectives:

1. How will a fuel shift towards low-sulphur fuels within the maritime

sector affect emissions of particles to air?

2. What are the emissions of NOX

3. Which aspects need focus when performing emission inventories

on a local level and how should these aspects be treated?

and particles during ships’

manoeuvring phases?

4. What improvements in air quality and damage reduction will

follow political incentive-based systems that target ship emissions?

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1.3 METHODOLOGICAL APPROACH AND SCIENTIFIC

FOUNDATION

The methodological approach for this research is founded in both

quantitative research with descriptive purposes and in more

qualitative research approaches. Although the descriptive analytical

studies (compare to the first and second research question) provide a

backbone for the research, a description of the methodological

approach using terms from the social sciences was found to be useful

in order to place the research in a wider scientific context. The

description of methodological approaches relevant for this work and

their influence on the choice of methods mainly follow terminology

from Arbnor and Bjerke (1997).

Science builds on different co-existing paradigms. Two of those that

are used in social science are the analytical theory and the systems

theory. This thesis, as a whole, has a scientific foundation in systems

theory, which considers a system to be more than the sum of its

interacting parts. However, specific studies within this research work

are of such character that they would more correctly be described by

means of analytical theory. Analytical theory can be described as

having an objective conception of reality that consists of summative

components.

A system on a conceptually high level is depicted in Figure 3. It is

believed that a high level representation of the system comprising the

studies will present a relevant context for the studies. The three

spheres of the system in Figure 3 are ‘nature’ which presents us with

resources to use and limits our actions when those resources are finite;

‘society’ which comprises any human artefacts and also all decision-

making that influences both technology use and the environmental

consequences; and finally the ship sphere which represents

‘technology’, which is all manmade and that causes changes in nature.

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These spheres are by no means specific for this research. All three

contain subsystems and a few of these subsystems are studied in this

work.

Figure 3. The nature–society–technology system. The directions of

interactions that are studied in are indicated by arrows

Typical subsystems of nature that have been considered in this thesis

are air and human health. Ships represent technology in this research,

and two examples of ships’ subsystems are engines and fuel. The

societal part of the system is, in a few aspects, part of the analyses but

in a static way; regulative measures are studied and provide input to

the work, although the potential influence of environmental

degradation on decision-making is not assessed. The interactions

between the society sphere and the other two has thus only been

regarded in one direction. The directions of the interactions that have

been studied are indicated by arrows in Figure 3.

Arbnor and Bjerke (1997) use the term ‘operative paradigm’ to

describe how a methodological approach is connected to a specific

study area. Another similar term is research design, as seen in Yin

(1994) and Bryman (2001), for example. The operative paradigm

comprises a study plan and a range of methods that suits the

methodological approach (Arbnor and Bjerke 1997), basically a way

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to move from research questions to conclusions. Following the systems

approach, for example, the case study is frequently used, since these

studies are able to treat whole systems with interacting units and can

then be used to represent certain types of systems. It is also common

to conduct personal interviews to gather information. Due to the

explicit focus on synergistic effects, analytical experiments that are

performed to reproduce causal relations are not relevant (Arbnor and

Bjerke 1997). Validation techniques in the systems approach school

relies on data collection from as many perspectives as possible and on

acceptance from groups within the system under study, while validity

in analytical research answers to what is measured by the technique

used, and whether the achieved results are true (Arbnor and Bjerke

1997).

Paper I and II are based on emission measurement studies. Focus in

paper I is the influence of a fuel shift from heavy fuel oil to marine

distillate oil while paper II quantifies emissions of certain pollutants

from ships during manoeuvring in and out of harbour. Referring to

Figure 3, the results have been placed in a context where they contri-

bute to a description of how ‘technology’ affects air quality, a sub-

system of ‘nature’.

Paper III is a trade-off study with a life-cycle perspective that

covers environmental effects within different impact categories. Also

in this study, the consequences in ‘nature’ from factors of ‘technology’

are assessed. This study comprises expansion of system boundaries in

order to better depict the actual system under study.

Paper IV presents a cost benefit study of regulative and voluntary

initiatives including a local emission inventory. Ships that called

Gothenburg during 2008 provide the study with case specific data. The

study considers costs and benefits from the initiatives and their effect

on emission levels. This study covers all three spheres; restrictions and

strategies to reduce emissions originate in the ‘society’, which leads to

technological abatement (subsystems of ‘technology’), and conse-

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quently changes pollutant levels in the air and reduces effects in

‘nature’.

Paper V includes a study on ship design. The approach in this study

takes a shipowner perspective and considers how requirements from

ship industry stakeholders could be used to design a ship based on

environmental objectives. The aim is to develop methods for use in

ship design and is mainly a study of how information on environmental

situations can be transferred to technological parameters during

design. Relations between subsystems on a ship were in focus. Two

interview series were conducted to provide information for the

analysis.

1.4 FRAME OF REFERENCE

This thesis is comprised of elements from the disciplines of chemistry,

environmental science and engineering. It also (although very

shallowly) touches upon both economics and law. The fact that a

research area cannot be placed in any single scientific discipline is a

main characteristic of interdisciplinary research. The qualities and

difficulties of interdisciplinary research as such, however, are in this

thesis only considered on an elementary intellectual level. A broad

research approach has a potential to produce results and descriptions

that are close to being put into use in, for example, decision-making.

The research work was started in 2001 as a response to an

increasing interest in environmental issues at the department of Naval

Architecture and Ocean Engineering at Chalmers University of

Technology. It was realised by many at this time that the

environmental effects from a ship throughout its lifecycle were

insufficiently considered when new ships were to be designed.

The initial theme of this research work comprised the incorporation

of environmental performance parameters in the design process of

ships and ship-based transport chains. The scope was focused around,

but not limited to, emissions to air from marine engines.

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As a set of environmental impact assessment methods were

examined, it became evident that some characteristics coupled to the

ship industry and ship transportation called for special attention in the

choice of assessment method:

1. The geography in the vicinity of the ship changes constantly and a

number of related factors such as local population density and

bedrock, determine the severity of any effect caused by emissions

from the ship.

2. The element of risk associated with environmental damage needs

to be treated in a life cycle assessment of ships’ transportation

due to the potentially large environmental consequences of a

single ship accident. The risk issue, which could be an oil spill to

give one example, is also traditionally managed by regulations

and indeed, certain ship dimensions are determined by risk

related aspects.

3. Ships are complex structures with subsystems that interact and

influence each other. Any adjustment in design parameters that

change the environmental performance of one subsystem will

affect the performance of others.

These three assumptions were considered in the study of suitable

methods for environmentally aware ship design methodologies.

Another assumption that was not directly related to the assessment

method but that became evident during the initial study on ship design

concerned the availability of data was:

4. There are indications of poor data on emissions from marine

engines for certain defined operational setups.

The research was presented in a licentiate thesis in February 2005 after

which there were two options for which direction to pursue: either the

environmental design methods should be validated with professional

16

ship designers within the industry, or the relevant data for

environmental impact assessments, the input to the methods, should

be studied and improved. The focus was lifted from the design and

company issues to questions concerning the quantification and

characterisation of emissions caused by ships and their effects.

Assumptions 2 and 3 were thus no longer relevant for further

consideration.

The initial study, presented in Paper V, shall consequently be

considered as a way to find the research questions for the following

research.

A few air-borne pollutants were then more closely studied as they

could be determined to cause a major part of the harm done by ships.

These were nitrogen oxides (NOX), sulphur dioxide (SO2

Because several new regulations that affect the emission factors for

NO

) and

particles.

X, SO2

In Figure 4 the relation between the studies conducted within the

scope of this thesis are presented together with the most important

defined areas within the frame of reference. The rectangles represent

divisions within different disciplines that have provided essential

information to the studies. The ellipses represent the conducted

studies. The results of the studies have contributed to the knowledge

base concerning abatement technology, emission factors and

evaluation of environmental damage, and taken together they

contribute knowledge of the local impacts of airborne emissions from

ships.

and particles had been developed around this time (~2007),

the fourth assumption listed previously seemed relevant to examine

more closely. This led to two field-measurements aimed at better

accuracy of input data under certain defined conditions. Thereafter, a

cost benefit study of policy options for reductions of ships emissions

including an inventory study considering effects in a port city was

conducted. The final study was completed in 2010.

17

Measurementstudies

Environmentalship design

study

LCA study

Emission factors

AbatementTechnology

Evaluation of environmental

damage

Ship design

Combustion

Plume chemistry

Regulation

CBA/ Emission inventory study

Localperspective on

air pollution from ships

Figure 4. Representation of the knowledge areas treated in the research. The

arrows represent outputs and inputs between the areas.

The disposition of the following text is such that each of the rectangles

will initially be treated followed by presentations of the conducted

studies (the ellipses) considering methods used, results and an overall

analysis of the results. The conducted studies are thoroughly described

in the appended Papers I-V.

18

19

2 SHIP ENGINES, FUELS AND POLLUTANT FORMATION

Ship engines are usually diesel engines of considerable sizes.

Approximately 67% of the world fleet use four-stroke diesel engines

for propulsion, and the rest are almost exclusively driven by two-

stroke diesel engines (data representative for 2002) (Corbett and

Koehler 2003). The speed of the engine in revolutions per minute

(rpm) at the crank shaft at design speed is another measure used to

determine the type of an engine. Slow speed diesel (SSD) engines are

typically large engines, mainly of the two-stroke principle, that run

between approximately 60 and 240 rpm; medium speed diesel (MSD)

engines are of smaller sizes in general, follow the four-stroke principle

and run between 240 and 960 rpm; and the high speed diesel (HSD)

engines are four-stroke engines that run at more than 960 rpm2

Table 2

. In

, some characteristics of different engine types are depicted.

About twice the amount of fuel combusted in medium speed

engines is used by ships with slow-speed engines (Buhaug et al. 2009).

Typical characteristics of marine diesels are that the combustion relies

on direct injection, that the inlet air is turbocharged and that they have

high thermal efficiencies (Heywood 1988). The thermal efficiency of

marine two-stroke engines can be up to 53% (Buhaug et al. 2009).

2 The limits between HSD, MSD and SSD used in Kuiken, K. (2008). Diesel Engines

I, for ship propulsion and power plants., have been used here, the engine speed intervals are

not definite

20

Table 2. Some typical characteristics of slow- medium- and high speed

engines

Engine type

SSD MSD HSD

Speed at crankshaft at design speed (RPM) <240 240-960 >960

Typical combustion cycle

2-stroke compression

ignition

4-stroke compression

ignition

Specific fuel oil consumption (g/kWh) 165-200 180-250

Share of installed power in the global fleet (2002) ~60% >40%

The combustion in diesel engines occurs at lean conditions when there

is an excess of air, even at low engine loads. In order to change power

output during the diesel combustion cycle, the amount of fuel injected

in the combustion chamber is varied while the inlet air volume is kept

almost constant. For ship engines, variations in the amount of inlet air

will occur despite this because the turbocharger operations depend on

the exhaust flow (Heywood 1988). Another important aspect for

pollutant formation in marine engines is direct injection, which causes

significant local variations in the combustion chamber in terms of

temperature and fuel to air ratios (Heywood 1988).

The majority of fuel types used by the international fleet today are

variants of heavy fuel oil (HFO). Heavy fuel oil contains residues from

refineries’ processing of crude oil and are highly viscous and need

heating before being used on board a ship. The trend in using heavy

fuel oil as a marine fuel started in the 1950s (Goodger 1982). In this

text, the term heavy fuel oil will be used for all fuel qualities

containing refinery residues, also covering so-called intermediate fuel

oil (IFO), which is HFO blended with refined oil qualities. There are

21

also marine distillate fuels (MD), which are refined products, although

certain classes of these might contain blend-ins of residues as well. A

selection of marine fuels and their typical characteristics are presented

in Table 3. In the previously referred to report from IMO a yearly

consumption of 76 million tonnes of MD and 256 million tonnes of

HFO were concluded upon for year 2007 (Buhaug et al. 2009).

Table 3. Typical physico-chemical properties of Heavy Fuel Oil and the

Marine Distillate Fuel types Marine Diesel Oil and Marine Gas Oil

(CONCAWE 1998; King et al. 2001; International Organization for

Standardization 2010).

Fuel type

HFO

MD

MDO MGO

ISO classification RMA, -B, -D, -E,-G,-K DMB DMX, DMA,

DMZ Sulphur content (%) (according to ISO classification)

<4.5 1

<2.0 <1.5

Contains residual oil Yes Yes No

Viscosity at 40°C (mm2/s) 10-700 11-14 1.40-6.00

Density at 15°C (g/cm3) 0.920-1.010 0.890 0.890

Ash (% m/m) 0.04-0.15 0.01 0.01

1

The sulphur content of MD are often below 0.5% (Cooper and Gustavsson

2004) and regional limits stipulate lower limits for both HFO and MD

The marine heavy fuel oil is characterised by high sulphur content,

high viscosities and densities and also high content of aromatics and

minerals (Cooper et al. 1996; CONCAWE 1998; King et al. 2001).

22

Also the marine distillate oils have high sulphur contents compared to

fuels used for land based transport. The content of polycyclic aromatic

hydrocarbons (PAH) in the fuel varies depending on whether it is

HFO or MD. Fuel analyses have also shown significant differences

within each fuel category that are due to differences during the

refining process (Buhaug 2010).

2.1 SULPHUR IN FUEL AND SO

The sulphur content of exhaust gases is directly proportional to the

amount of sulphur in the fuel burnt. The sulphur is chemically bonded

to the hydrocarbons of the fuel and during the combustion, most

sulphur is oxidised to SO

2

2. SO3 will also be formed in minor amounts.

The ratio between SO2 and SO3 is typically 15:1, according to MAN

B&W Diesel (1996). SO3 will react readily with water to form H2SO4

Sulphur contents in marine fuels are limited by the IMO to 4.5%

(45000 ppm). The worldwide average, as estimated by Eyring et al., is

around 2.4% (24000 ppm) although subject to change due to coming

legislations (Eyring et al. 2005). The sulphur limits are lower in certain

areas, and a schedule for the regulation of overall sulphur limits exists.

However, the limits are significantly higher than those for transport

modes on land, which can be in concentrations of 10 to 50 ppm.

,

which is very corrosive.

The SO2

3.1.2

oxidation process and the formation of sulphate particles

in the atmosphere are further described in .

2.2 NITROGEN OXIDE EMISSIONS FROM SHIPS

NOX is a collective name for NO and NO2, where NO is by far the

most abundant in exhaust gases. About 5-7% of NO is converted to

NO2 in the exhaust system or engine (Henningsen 1998). The share of

NO2 in NOX that leaves the combustion chamber is partly determined

by local temperature conditions (Heywood 1988). According to MAN

B&W Diesel, approximately 1% of NO will form N2O (MAN B&W

23

Diesel 1996), although this figure is significantly higher than what is

presented by Cooper (Cooper 2001). The high rate of NO formation is

related to high temperatures during combustion, the duration of these

periods, as well as high oxygen concentrations (Heywood 1988).

The chemical reactions underlying the majority of NO formation

are referred to as the extended Zeldovich mechanism and include the

reaction steps (1) - (3):

O + N2 (1) ↔ NO + N

N + O2 (2) ↔ NO + O

N + OH ↔ NO + H. (3)

NO production is very efficient at temperatures above 2,000 K,

resulting in a net production of NO during combustion and in the post-

combustion gases (Bowman 1975). The peak temperature during

combustion in large marine diesel engines is between 2,200 and 2,400

K (Lyyränen et al. 1999; Henningsen 2010). Slow speed engines have

higher specific emissions of NOX

Additional NO is formed from nitrogen in the fuel or via reactions

between molecular nitrogen and the hydrocarbon species in the fuel.

While Heywood states an average nitrogen content of heavy distillates

of typically 1.40% by weight (Heywood 1988), the nitrogen contents of

nine marine HFOs from published emission measurement studies

were all below 0.5% (Lyyränen et al. 1999; Cooper 2003; Fridell et al.

2008; Winnes and Fridell 2009; Winnes and Fridell 2010). Nitrogen in

fuel has been shown to be an important source for NO, especially at

high air to fuel ratios (lean to stoichiometric conditions) during

combustion (Bowman 1975). The lean combustion of diesel engines

and a relatively high concentration of nitrogen in heavy fuel oils make

fuel nitrogen a potential contributor to significant NO

than engines of higher speeds

(Cooper and Gustavsson 2004).

X concentrations

24

in ship exhausts. Other formation pathways exists but are less

important (Bowman 1973; Heywood 1988).

2.3 PARTICLES FROM COMBUSTION IN MARINE ENGINES

A particle is defined by Finlayson-Pitts and Pitts (2000) accordingly:

‘Particles, or particulate matter, may be solid or liquid, with diameters

between ~0.002 and ~100 µm. The lower end of the size range is not

sharply defined because there is no accepted criterion at which a cluster

of molecules become a particle. The upper end corresponds to the size

of drizzle or very fine sand; these particles are so large that they quickly

fall out of the atmosphere and hence do not remain suspended for

significant times.’

Particle formation during combustion (primary particles) occurs via

different routes that start with the condensation of volatilized species

in the hot exhaust gas which occurs at supersaturation conditions.

These particles have diameters between 0.01 µm and 0.08 µm (Amann

and Siegla 1982). Particles of these sizes undergo coagulation when

they collide with other particles, increasing the size of the average

particle and reducing the number of particles. The mode of primary

particles from combustion in marine diesel engines has been

quantified from observations on board or in test beds by Lyyränen et

al. (1999), Kasper et al. (2007), Fridell et al. (2008), Moldanová et al

(2009) and Petzold et al. (2008). Growth of particles also occurs by

surface condensation of volatile species on already existing particles

(Finlayson-Pitts and Pitts 2000).

Particles from marine diesel engines have been observed to differ in

certain aspects from particles from other sources. Moldanová et al.

(2009) observed differences in the typical soot like particles and

Kasper et al. (2007) observed different mass size distribution than

what was seen in tests on a car engine exhausts.

Exhaust gas measurements on marine diesel engines have shown

particle mass size distributions of bimodal character with one mode at

25

0.06-0.5 µm and one mode around 7-10 µm (Lyyränen et al. 1999;

Lyyränen et al. 2002; Fridell et al. 2008; Moldanová et al. 2009). The

mass size distributions are different from number size distributions.

Typically, a mode where particle diameters are <0.1 µm will dominate

in number, and the particles in the coarse mode (diameters >2.5 µm)

will dominate in mass, see Figure 5. Number concentrations have been

observed to be less when running marines engines on HFO compared

to combusting MD, while the mass of emissions are higher during

periods of HFO combustion (Kasper et al. 2007; Winnes and Fridell

2009).

0.1 10.01

Accumulation mode

Coarse particles

Ultrafine

Particle diameter (µm)

Mass concentration

Number concentration

10

Fine particles

0.001

Figure 5. Schematic picture depicting typical primary particle size

distributions from marine diesel engines. Names and ranges of size classes

adapted from Finlayson-Pitts and Pitts (2000).

As particles of around 10 µm diameters are not generally formed by

coagulation mechanisms, there is reason to believe that these particles

are caused by re-entrainment of particulate material attached to the

walls of the exhaust gas system (Lyyränen et al. 1999). Another

explanation is that these particles come from incomplete combustion

of less volatile fractions of HFO. Moldanová et al. (2009) found char

and char-mineral in sizes up to 5 µm particle samples, while

26

Popovicheva et al. observed char particles of up to 10 µm diameters

(Popovicheva et al. 2009).

2.3.1 PARTICLE COMPOSITION

The generally high levels of particles found in ship exhausts are due to

both fuel quality and the diesel combustion characteristics. In general,

the particulate emissions from ships are constituted by the fractions

elemental carbon, organic carbon, sulphates and ash residues.

Typically, soot formation can to a large part be explained by

combustion aspects.

Several chemical mechanisms are involved in the formation of soot

from the hydrocarbon molecules in the fuel (Heywood 1988). Soot

consists mainly of hydrogen and carbon with a molar ratio in freshly

formed soot of H/C of 1 (Warnatz et al. 2006). In the diesel cylinder,

soot particles originate as a hydrocarbon chain or aromatic ring onto

which other hydrocarbon compounds attach. PAHs in particular have

been identified as precursors of soot formation (Amann and Siegla

1982; Warnatz et al. 2006). The precursors of soot, the uncombusted

hydrocarbons, result from the combustion of fuel air mixtures that are

too lean or too rich. Too lean mixtures will not ignite and too rich

mixtures will not fully oxidise the hydrocarbons. Therefore, the local

variations within the combustion chamber are central to the formation

of particles (Warnatz et al. 2006). The mechanisms involved in the

formation of soot are still not completely understood.

Typical fuel characteristics that may cause elevated levels of

particles in exhaust gases of ships are the content of sulphur, minerals

and aromatics.

Sulphur, which is mostly oxidised to SO2 during combustion, is a

major constituent of the primary particles in the exhaust from marine

engines from the combustion of HFO (Kasper et al. 2007; Agrawal et

al. 2008; Petzold et al. 2008; Moldanová et al. 2009; Popovicheva et al.

2009). Sulphate particles in the exhaust system form during the cooling

27

of the exhausts and a reaction between SO3 and water, which forms

H2SO4

The transition metal content of the particles varies but typically

includes vanadium, nickel, calcium, zinc and iron (Lyyränen et al.

1999; Moldanová et al. 2009; Popovicheva et al. 2009). These elements

originate from the fuel and also from fuel additives and lubricant oils

(Lyyränen et al. 1999; 2002). Lyyränen et al. also observed that

particles were formed around minerals from the heavy fuel oil and

both number and mass concentrations were observed to increase with

an elevated ash content (Lyyränen et al. 1999).

. Kasper et al. (2007) found that 1.4% of the sulphur in the fuel

was in the form of sulphate in exhaust gas particles. Agrawal et al.

(2008) showed a sulphate particle formation between of 3.7-5% for

the same mechanisms during exhaust gas measurements after dilution

with air, while Moldanová et al. concluded on 1.3% (Moldanová et al.

2009).

Aromatics ignite slowly, and the higher the aromatic content in the

fuel, the longer it takes before the fuel spray is ignited, known as the

ignition delay period. This effect, however, can be partly compensated

for by the addition of fuel additives according to Heywood (1988). A

long ignition delay period may cause lean mixtures in the combustion

chamber which leads to elevated amounts of hydrocarbons in the

exhausts (Lyyränen 2006).

28

29

3 QUANTIFICATION OF AIR POLLUTION FROM SHIPS

The atmospheric transportation of pollutants from ships will influence

regional background pollution levels. The dispersion, pathways and

fates of NOx, SO2

As a plume is dispersed, the primary particles (diameters <0.1µm)

within it will coagulate or condensate onto existing surfaces which

results in decreased number concentrations and larger average sizes of

particles (Russell et al. 1999; Petzold et al. 2008; Lack et al. 2009). As

the particles grow to between approximately 0.08 and 1-2 µm, often

referred to as the accumulation mode, they typically stay in the

atmosphere for 1 to 10 days. Also, NO

and particles in ship exhaust have been the subject

of many plume measurements (Russell et al. 1999; Hobbs et al. 2000;

Isakson et al. 2001; Sinha et al. 2003; Chen et al. 2005; Lu et al. 2005;

Petzold et al. 2008; Lack et al. 2009), satellite observation studies

(Beirle et al. 2004; Richter et al. 2004), and chemical transport

modelling studies (Kasibhatla et al. 2000; Davis et al. 2001; von

Glasow et al. 2002; Endresen et al. 2003; Song et al. 2003; Derwent et

al. 2005; Dore et al. 2006; Corbett et al. 2007).

2 and SO2

As ships influence their surroundings with pollutant emissions, the

effects at different places depend on the dose or concentration that

reaches that specific place and the sensitivity or response at that

particular location.

have been shown to

remain in the atmosphere long enough to cause a large amount of

these pollutants to reach coastal areas (Davis et al. 2001; Endresen et

al. 2003; Sinha et al. 2003; Beirle et al. 2004; Chen et al. 2005; Petzold

et al. 2008; Lack et al. 2009).

30

3.1 EMISSION INVENTORIES

The approach to emission inventories can be categorized as either

bottom-up or a top-down. An inventory with a bottom-up approach

will consider spatially resolved ship activity data including specific data

on engine sizes, engine loads, fuel type, operating profiles and other

aspects related to the combustion and the ship in order to determine

the emission load. Top-down approaches break down data on fuel

consumption and attribute emissions totals to the emission sources.

Top-down approaches have benefits over bottom-up approaches as

they are less time-consuming while the detail level can be higher in the

bottom-up approach. Global inventories can use models with elements

from both methods; details on specific ships or ship types result in

estimates on global fuel consumption and emissions and are combined

with spatially resolved models on the activity of the global fleet

(Endresen et al. 2003; Eyring et al. 2005). The result of top-down

approaches have been seen to deviate considerably from local port

inventories with bottom-up approach (Wang et al. 2007).

Three modes of ship operation should be distinguished in any study

of emission to air from ship. These modes are ‘at sea’, ‘manoeuvring’

and ‘at berth’, which besides the obvious features inherent in their

names, are also characterised by different typical engine operations.

Ships ‘at berth’ only employ the auxiliary engines while the main

engine(s) normally are shut down. During the ‘at sea’ and ‘manoeuv-

ring’ modes, the main engine(s) are used for propulsion, and auxiliary

engines are kept running in order to supply the ship with electricity.

Many ships also use the auxiliary engines to supply power to their bow

thrusters during the manoeuvring stage. One exception to these

general statements is the option to connect the ship to shore side elect-

ricity when at berth, which is a service that is provided in a limited

number of ports. Another exception is that auxiliary engines can be

shut down at sea if a generator is installed, which can provide elect-

ricity needed from the main engine. A few studies also point at a

31

significant contribution of certain emissions from boilers that are used

to produce steam on board. This seems limited to certain ship types

(Whall et al. 2002; Hulskotte and van der Gon 2010).

The majority of marine fuels are combusted during ships’ ‘at sea’

mode. The main engines ideally run on the speed they were designed

for, and the combustion is typically very efficient. Dalsøren et al.

estimate that approximately 5% of the total global fuel consumption

by ships are used in port (Dalsøren et al. 2009).

Emission inventories covering the global fleet have been produced

from 1997 and onwards (Corbett and Fischbeck 1997; Corbett et al.

1999; Corbett and Koehler 2003; Endresen et al. 2003; Eyring et al.

2005; Endresen et al. 2007; Buhaug et al. 2009; Dalsøren et al. 2009;

Paxian et al. 2010). There are some discrepancies concerning methods,

base year, and the scope of covered ships and ship engines among the

different studies, and consequently the results differ between the

studies. A brief overview of inventories from different research groups

and their respective results are presented in Table 4.

3.1.1 EMISSION FACTORS

Specific emissions (typically mass of pollutant per work performed by

the engine or per mass of combusted fuel) of pollutant species differ

between the operational modes due to the combustion characteristics

at different loads and at transient operations. The units of specific

emissions, g/kWh or g/kg fuel, are related to each other by the specific

fuel consumption (sfc), which differs among engine types. The sfc will

also depend on the fuel type due to the differences in specific heat

among fuels. The sfc for modern marine engines range between 165

g/kWh for the most efficient two-stroke engines to around 230 g/kWh

for small four-stroke engines (Buhaug et al. 2009).

Emission factors play an important role in inventories of air

pollutants. In Table 4 the emissions factors for CO2, NOX, SO2, PM,

32

HC and CO in g/kg fuel used in the inventories mentioned previously,

are presented together with their cited sources.

The values presented in Table 4 merely demonstrate the difficulties

of drawing conclusions on emission factors for even the most abundant

pollutants from ship engines. The reader should remember that the

inventories cover the global fleet, which makes aggregated factors like

the ones presented subject to many estimates, for example estimates

on average fuel type and average engine type. Emissions from test bed

engines can be suspected of deviating from emissions from engines in

operation due to wear on the engine and how it is operated. However,

correlations of specific emissions based on engine size or engine age,

for example, have proven difficult to determine due to limited datasets

and large variations in data (Whall et al. 2002). The specific emissions

from 155 measurements from ships and test bed measurements in

Wärtsilä’s facilities comprising five of their most common models are

related to the rpm of the engine in Figure 6 (Whall et al. 2002; Agrawal

et al. 2008; Winnes and Fridell 2009; Winnes and Fridell 2010). The

measurements from Whall et al. are reported in an aggregated way. In

Figure 6, these measurements are presented as average emission

factors at 500 rpm for MSD engines and at 100 rpm for SSD engines.

They are also weighted by the number of measurements.

33

Table 4. Emission factors and estimates of fuel consumption for the

international fleet from recent global inventories.

Inventory study

Corbett and

Koehler, 2003

Paxian et al., 2010

Dalsøren et al., 2008

Buhaug et al., 2009

Source of emission factor

Entec, 2002

Test bed results,

(see Eyring et al 2005)

Cooper, 2004, Entec, 2002

CORINAIR, IPCC

(HFO/MGO)

Total Fuel consumption (MT/year)

289 (2002) 221 (2006) 217 (2004) 276 (2007)

Included in the fuel estimate

International shipping, Military vessels

All ships All ships Non-military international

shipping

CO2 3179 (g/kg fuel) 2905 3179 3130/3190

PM (g/kg fuel) 6.1 6.0 7.6 6.7/1.1

NOX 82.5 (g/kg fuel) 76.4 41 - 92 85 and 56**

S content of fuel (%) 2.5% 2.4-2.6% 54 or 10

(g/kg fuel) 2.7%/0.5%

HC (g/kg fuel) 2.9 7.0 2.45 2.7

CO (g/kg fuel) - 4.67 7.4 7.4

* Original emission factors are in the unit g/kWh; these values have been

converted to emissions in g/kg fuel by division of a specific fuel consumption

of 206 g fuel/kWh which is used in by Corbett and Koehler (2003)

** kg NOX

/tonne fuel for slow-speed and medium-speed diesel engines,

respectively, independent of fuel type.

The report from Entec, referred to as Whall et al. (2002), contain an

extensive data set from on board measurements. The relative uncer-

tainties at a 95% confidence interval related to the different emission

factors are estimated in the report. Manoeuvring operations are

estimated such that the most uncertain emission factors vary from 30

to 50%. For ‘at sea’ operation, the uncertainties range from 10% for

34

SO2, CO2 to 25 % for HC and PM, while the NOX

emission factor has

an uncertainty of 20%. Emission factors for ‘at berth’ operations are

between 20 and 40%. In two of the global inventories, the largest

sources of uncertainty for fuel consumption estimates is reported to be

average engine load and the days at sea (Corbett and Koehler 2003;

Buhaug et al. 2009).

0

5

10

15

20

25

0 500 1000 1500 2000

Spe

cific

em

issi

ons

of N

OX

(g/k

Wh)

RPM of crankshaft at design speed

NOX (g/kWh)

IMO Tier I

IMO Tier II

IMO Tier III

Figure 6. Specific emissions from 155 measurements on board ships (113)

and in test beds (42). The grey solid line is an approximated function of

specific emissions related to the rpm, based on the measurements.

Ship emission inventories that cover a local scale and aim at a detailed

analysis of ships’ contribution to the air quality of port cities often rely

on very specific data on number of ship calls, ship types and sizes as

well as time at berth. In these studies, pollutants such as NOX, SO2,

PM and ozone are more interesting than CO2, which has effects on a

global scale. Examples of studies that cover a local area are (Trozzi et

al. 1995; Saxe and Larsen 2004; Lucialli et al. 2007; Marr et al. 2007;

Yang et al. 2007; Yannopoulos 2007; De Meyer et al. 2008; Schrooten

et al. 2008; Vutukuru and Dabdub 2008; Deniz and Kilic 2010; Song et

al. 2010; Tzannatos 2010).

35

Uncertainties related to the emission estimates in local inventories

are discussed in a few studies (Yang et al. 2007; Schrooten et al. 2008;

Tzannatos 2010) while other studies focus primarily on the

performance of the dispersion models used (Lucialli et al. 2007;

Yannopoulos 2007; Song et al. 2010) and the correctness of

assumptions that are used as input to these models such as chimney

height and surface roughness (Saxe and Larsen 2004; Yannopoulos

2007). It is likely that on a local scale, the operational phases of the

ships can be determined with a higher degree of certainty than in a

global analysis since the number of days out of service during a year is

unimportant and because the time at berth and time spent

manoeuvring can be determined by speed limits and port data. Yang

et al (2007) list the applicability of generic emission factors as the

major source of uncertainty followed by the uncertainties related to

engine power estimates.

The case of particles

Particle emission factors contain a high level of uncertainty, especially

for the manoeuvring mode and at berth conditions. The reasons for

this are variations in emissions due to differences in fuel and

combustion specifics and too few input data, which most likely is a

consequence of two factors; fewer incentives for measuring particles

than regulated emissions: and second more complicated measuring

techniques compared to the gas measurement techniques.

Results from epidemiological studies indicate that particles in the

fine and ultrafine size modes cause more health risks than particles in

the coarse mode (Lighty et al. 2000; Pope and Dockery 2006). This is

an indication that number concentrations is a more accurate measure

than mass concentrations to describe particle emissions; coarse PM

can dominate the mass concentration of the aerosol particles, while the

number concentration is a more relevant value in order to conduct

evaluations of potential impacts.

36

A literature review on particle emission factors was conducted in

connection with one of the on board emission measurement studies. In

accordance with theory, the data clearly indicated a dependence of PM

emissions on sulphur content in fuel, although there is very little

available data from similar studies. Results from test-bed emission

measurements are vast but not always made available and are rarely

presented in refereed material. A report by IMO presents a set of test-

bed measurement results from combustion in large-scale diesel

engines and the dependence of particle emissions of sulphur content of

fuel. The fuel types are not specified (Buhaug et al. 2009).

3.1.2 WITHIN THE SHIP PLUMES

The exhaust plumes from ships at sea can remain in the relatively still

marine boundary layer for a long time. Estimations by measurements

and chemical modelling of ship plumes have shown that they can last

from one to two days (von Glasow et al. 2002; Petzold et al. 2008).

The plumes are physically dispersed and mixed with air. Plume

dispersion depends on the wind strength and air turbulence. Chemical

species within the plume react with each other and are removed by

particle scavenging and surface deposition. Within the plumes, the

concentrations of pollutant species are high relative to the ambient air,

which leads to elevated reaction rates. The concentrations of reactive

radical species are important in these reactions. The reaction rates and

deposition rate of a pollutant will determine its atmospheric lifetime3

The number concentrations of particles found in ship plumes have

been observed to peak at diameters of 0.01-0.10 µm (Russell et al.

1999; Hobbs et al. 2000; Petzold et al. 2008; Lack et al. 2009), which is

and its fate.

3 The lifetime of a compound is defined as the time it takes to reduce the

concentration of the compound to 1/e (~37%) of the initial concentration.

37

in accordance with results from on board measurements. The

timescale for a particle in this size mode is in the range of minutes to a

day at atmospheric conditions. Hobbs et al. also observed that ships

burning distillate fuels (with gas turbine propulsion) emitted smaller

particles than engines burning heavy fuel oil. Typical number

concentrations are between 10,000 and 100,000 per cm3

The dominating fates for SO

at

measurements in a fresh plume (Hobbs et al. 2000; Sinha et al. 2003;

Chen et al. 2005; Petzold et al. 2008).

2 in the atmosphere are oxidation or

dry deposition. Endresen et al. (2003) estimated that approximately

half of the amount of emitted SO2 from ships was deposited, mainly

on the sea surface, by dry deposition. SO2 oxidises to H2SO4 and

sulphates in the atmosphere. Two different pathways for H2SO4

formation: either gaseous SO2 reacts with hydroxyl radical molecules

(·

The levels of SO

OH), or it reacts heterogeneously in the liquid phase or on surfaces

(Finlayson-Pitts and Pitts 2000).

2 in a plume have been observed to reach

background concentrations after a couple of hours, (Chen et al. 2005),

and the lifetime of SO2 in a plume has been estimated by modelling to

be 0.5-2 days (Davis et al. 2001). SO42-

NO

increases the hygroscopicity of

particles, which reduces the lifetime of the particles in the atmosphere

due to cloud formation around the particles and the subsequent

precipitation.

X is involved in several photochemical reactions in the

atmosphere, and due to the high NOX concentrations in ship plumes,

their chemistry is influenced by the incoming solar radiation.

Consequently, the chemical pathways and lifetimes of NO and NO2

Lifetimes of NO

will differ between tropical regions and mid-latitudes, and between

emissions at night and during the day.

X have been estimated from observational studies.

Chen et al. found that 80% of the emitted NOX from a ship off the

coast of California were removed within 2.5 hours (Chen et al. 2005).

Beirle et al. concluded that NOX lifetime was, on average, 3.7 hours

38

based on data from satellite detections of NOX

There are two major sinks for NO

from ships in service

between Sri Lanka and Indonesia (Beirle et al. 2004).

X in the ship plume. One is HNO3

that is formed in a reaction between NO2 and OH. The other main

sink for NOX is the nitro organic compound peroxyacetyl nitrate,

PAN. Chen et al. (2005) estimate that about 20% of NO forms PAN,

which can be transported over long distances. The reactions are

chemically reversible and none of the sinks permanently remove NOX

3.2 CONSIDERATIONS IN LOCAL INVENTORIES

from the atmosphere.

Locally, air quality can be affected by intense traffic, and criteria

pollutants often exceed guideline limits in large cities. Port cities do

not necessarily experience worse situations than other busy cities but

have an additional source of air pollution that has been recognised in

several studies (Isakson et al. 2001; Saxe and Larsen 2004; Itano et al.

2005; Lucialli et al. 2007; Marr et al. 2007; Wang and Corbett 2007;

Yang et al. 2007; De Meyer et al. 2008; Schrooten et al. 2008;

Vutukuru and Dabdub 2008; Winnes and Fridell 2010). The ships’

influence on air quality depends on meteorological conditions, local

topography and ship traffic density.

In order to determine the contribution to local air pollution from

ships, all operational modes should be considered. The relative

importance of the modes ‘manoeuvring’ and ‘at berth’ will increase

compared to their influence in global inventories. The time at berth is

partly related to the type of ship, and lay times for different segments

and ship sizes vary. Dalsøren et al. studied times at different opera-

tional modes and found that the time at sea during a year varied from

280 days for large cargo vessels to 130 days for small cargo vessels

(Dalsøren et al. 2009).

During manoeuvring in and out of a harbour, the main engines are

exposed to variations in loads that result in fluctuating levels of

39

pollutants in the exhaust gas. Typically, NOX emissions will fluctuate

at low levels, while particles, hydrocarbons and carbon monoxide

fluctuate at high levels. SO2 and CO2

Emissions at different places and at different times will cause

different degrees of damage to surrounding environments and to

human health: susceptibility to acid deposition will depend on the

buffering capacity of the bedrock; typically carbonate rich minerals

such as limestone have a high buffering capacity while granites have

low buffering capacity and thereby are sensitive to acid deposition,

different crops are reacting differently to similar levels of ozone

(Sellden and Pleijel 1995; Ashmore 2005) and population density and

demographic composition will determine the effects of health altering

pollutants in the atmosphere. These responses may be linearly or

exponentially related to ambient concentrations. Certain response

functions are characterised by critical concentration threshold levels

above which the effect of the pollutant becomes increasingly severe.

Others, such as particles, seemingly have no such ‘no-effect’

concentration and have effects at the lowest potential ambient levels

as well (World Health Organization 2006). Therefore, peak

concentrations that may occur during specific meteorological

conditions such as ground inversions or during periods with extreme

pollutant loads will potentially cause proportionally large damage.

will be low due to low oil

consumption. Emissions of particles have observable peaks in number

concentrations at engine start up and shut down. However, the

manoeuvring period is normally short and the absolute amounts of

emissions are often negligible in a global perspective. In previous

research little attention has been paid to emissions from manoeuvring

ships.

40

41

4 EVALUATION OF ENVIRONMENTAL IMPACTS

There are numerous frameworks for the assessment of environmental

impacts. The studies within this thesis use three different approaches

to evaluate environmental impact. Two of those, life cycle assessment

(LCA) and external cost estimates used in cost-benefit analyses, will

be briefly presented in the following paragraphs. The third is based on

methods from the systems engineering discipline and directs the design

team of a ship. For a description of this method the reader is referred

to Winnes (2005) and Winnes and Ulfvarson (2006).

When using life cycle assessment methods, an inventory that covers

resource use, energy use and emissions from activities within chosen

system boundaries is conducted. The collected data are related to a

functional unit: a measurable unit that describes the utility provided by

the studied product or service. The data on emissions and other

aspects are then grouped in categories corresponding to their

characteristic impacts. Within each category, the relative importance

of the different activities can be assessed in order to determine which

activities are most detrimental. A following step can be to conduct a

valuation analysis where impact categories are weighted and

aggregated to a one-dimensional value. The valuation procedure is an

optional step in the standard from International Standardisation

Organization (ISO) that treats LCA (SIS 2002).

By following the LCA procedure, the environmental impact from a

set of studied activities can be accounted for. The impact is also

related to the purpose of a product or a service. If the study comprises

several alternative services or products with similar functions,

estimations on favourable options from an environmental perspective

can be made.

A valuation of environmental effects is often based on subjective

judgements. In LCA practice, methods can be based on expert

42

judgments (Goedkoop and Spriensma 2000), the distance to a political

target (Baumann and Tillman 2004) or other approaches. In order to

conduct cost-benefit analyses (CBA), the environmental damage

needs to be quantified in terms of costs. The benefits that society

experiences from avoiding costs like these external costs or

externalities can then be related to project costs such as installation of

abatement equipment. CBAs are used for both project evaluation and

regulatory review and has a longer tradition in the US than in Europe

(Navrud and Pruckner 1997).

The calculation of external costs is an estimation of the costs that

originate from degradation of environmental assets and damage to

human health. Goods without a market price are valuated by revealed

preference methods and stated preference methods, where the first

method estimates values for goods based on what people pay for them,

and the last bases estimates on what people state that they are

prepared to pay for a good.

A European project, the ExternE, developed an approach for

calculation and valuation of externalities of energy that has become

widely used. It is referred to as the Impact Pathway Approach (Institut

für Energiewirtschaft und Energieanwendung and Universität

Stuttgart 2005). Essentially, it suggests that potentially harmful

substances should be followed from exhaust gas emissions via

dispersion, transformation, exposure and quantification of impacts to a

final valuation of the effects. ExternE, as far as possible, bases its

valuation of air pollution on willingness-to-pay studies based on

revealed preferences but also uses market prices (Institut für

Energiewirtschaft und Energieanwendung and Universität Stuttgart

2005). External cost factors for emissions from ships have been

estimated by this methodology in several studies. Together, the

differences in valuation of life years and statistical life, the different

estimates of what part of the emission reaches shore and the level of

detail concerning the effects produce the range of values that are

43

presented in Figure 7 (Holland and Watkiss 2002; Holland et al. 2005;

Bickel et al. 2006; SIKA 2009).

1

10

100

1000

10000

100000

1000000

10000000

Regional (Emissions from the North Sea)

Regional (Emissions from the North Sea)

Regional (Emissions from the North Sea)

Urban (City with 500,000

inhabitants)

SO2 NOX PM2.5 PM2.5

Cos

t (€/

tonn

e po

lluta

nt)

Figure 7. Ranges of external cost estimates for SO2, NOX, and PM2.5 from

three different projects; CAFE-CBA, HEATCO and ASEK. CAFE-CBA

and HEATCO are projects with European scope while ASEK only considers

effects in Sweden. Costs are in €2005

/tonne pollutant.

As is seen in Figure 7, there are large variations between the estimates

of the same pollutant. In order to produce reliable results in a study of

externalities, a single estimate is not sufficient.

Wang et al. (2007), Bosch et al. (2009) and Tzannatos (2010) are

examples of studies on externalities caused by ships. Tzannatos

estimate the experienced externalities from ferries and cruise ships in

the port of Pireaus. The two other studies investigate the costs and

benefits associated with regulatory measures. Wang et al. (2007) study

the potential effects of reducing SO2 emissions from ships by

44

designating the US west coast as an emission control area. The ratios

of benefits over costs are in favour of regulations to limit SO2 over a

range of fuel costs and benefit values. Bosch et al. (2009) study

alternative scenarios and the potentials of expanding the European

emissions control areas. The study is conducted for the European

Commission as a support in the revision of the Directive 1999/32/EC

on the sulphur content of certain liquid fuels.

45

5 TECHNOLOGICAL IMPROVEMENT POTENTIALS

Several options that reduce air pollutant emissions from marine

engines are available today. The increased widespread use of them is

largely driven by regulative measures, although some examples of

successful voluntary initiatives exist.

5.1 LIMITATIONS DUE TO THE SHIP DESIGN PROCESS

A study of the life cycle of ships as constructions reveals several

obstacles for environmental improvement. The expected lifetime of a

ship is around 30 to 35 years. UNCTAD reports that the average age

of ships at demolition yards was around 30 years in 2009 for selected

ship types (Asariotis et al. 2009). As a consequence, a large part of the

fleet has technical solutions that are restricted to a knowledge base

from the year that the ship was constructed. The data used during the

decision-making process of the ship design will influence the environ-

ment around the ship for tens of years.

Ships are different from many other technical devices in the sense

that they are normally produced as one of a kind. This means that no

prototypes are made, but instead experience from one ship is assessed

and may cause incremental improvements on subsequent designs.

Narrow time limits during the design process place further demands

on precise information on environmental performance at early stages

in the design phase in order to achieve high environmental perfor-

mance. As described in Paper V, all data for decision-making on

exhaust gas cleaning equipment needs to be treated within a time

window, open in the range of a few weeks to a couple of months,

concurrently with decisions on speed and power requirements

(Interview series 1 2001 - 2002; Interview series 2 2003).

46

Following the initial mission analysis that describes what types of

goods are to be transported, how they will be loaded onto the ship,

which routes the ship will sail, how long it will be in service, and other

factors, a series of iterative decision-making about hull dimensions,

powering and on board arrangements are started. Parameters become

more and more inflexible as the process proceeds, allowing only minor

detail changes in the final iterations (Wijnolst 1995; Interview series 2

2003). The complexity of technical systems on board a ship together

with the limited space means that the introduction of new equipment

will be costly for the shipowner. This is a contributing reason to the

low frequency of integration of environmental aspects into the ship

design process.

5.2 TECHNOLOGICAL IMPROVEMENTS

The strategy for the abatement of a pollutant will be designed in

consideration of the mechanisms behind the formation of the

pollutant. Accordingly, NOX emissions are abated by modifying

engine parameters that reduce the temperature of the combustion air

or the time at peak temperatures. Sulphur dioxide emissions are

reduced by removing sulphur from the fuel in a refinery. Both of these

species can also be abated by after-treatment, which means that they

are allowed to form but are removed from the gas phase emissions.

Particles are complex pollutant groups that comprise a number of

chemical species. Particles are mainly targeted by the same abatement

strategies that are used for SO2

Using low-sulphur oil is an obvious way to reduce SO

.

2-emissions.

The switch from fuel oil with high sulphur content to oil with lower

sulphur concentrations can be done either by switching to heavy fuel

oil with low sulphur content or to marine distillate oil (MD). The finer

quality oil is more common to use in medium and high-speed engines.

An alternative to using the low-sulphur fuels is to use scrubbers of

different designs. The scrubber decreases the concentrations of SO2

47

and particle levels in the exhaust gases by capturing them in an

alkaline liquid stream. Sea water as well as aqueous alkaline chemicals

can function as scrubber liquid. Scrubbers that use sea water are

referred to as open systems while scrubbers using an industrially

produced alkaline chemical are referred to as closed systems. In both

systems the scrubber liquid is filtered before effluents are released into

the surrounding water. The sludge from the process is disposed of at

port facilities. Allowing water that has cleaned the exhaust gases from

SO2

The technological solutions that are used to reduce NO

and particles into the water can cause damage to marine eco-

systems because it contains contaminant residues from the exhaust

gases. The effluent from the open scrubber system will also be acidic

unless it is diluted prior to the outlet (Karle and Turner 2007). Model-

tests indicate rapid dilution from ships in full speed in open water,

although the dilution in ports is likely to be slower and will rely more

on local conditions (Buhaug et al. 2006). The scrubber has been

proven to be a cost-efficient alternative to low sulphur fuels. The

number of installations of scrubbers on commercial ships is, however,

very low and installations are therefore associated with uncertainties

regarding operational reliability and costs. The cleaning capacity of

scrubbers is determined by the amount of the scrubber fluid and by its

alkalinity (Andreasen and Mayer 2007).

X

In order to comply with Tier I, a few basic internal engine

modifications are sufficient. These modifications include valve and

nozzle modifications of slow speed engines. The modified valves lower

the NO

emissions

from new ships are developed to suit the requirements in the three

tiers of MARPOL Annex VI. Tier I requires reductions of

approximately 5-15% from a base line value for slow and medium

speed engines (Cooper and Gustavsson 2004), with further reductions

of 15-20% in Tier II. Additional reductions of 75% for ships in the

emission control areas of Tier III will be valid from 2016.

X emissions by approximately 20% but were originally inten-

48

ded to reduce HC and particulates (Goldsworthy 2002; Entec UK

Limited et al. 2005; Henningsen and Aabo 2007).

More advanced internal engine modifications entail changes in

compression ratio, injection rate shaping, and time of injection, among

others. Most of these technologies lead to reductions in NOX

The scheduled NO

emis-

sions of up to 30% due to lowered temperatures during different

combustion stages, but will as a side effect reduce combustion

efficiency (Goldsworthy 2002; Entec UK Limited et al. 2005).

X regulations in Tier III require NOX

The water-based technologies can be divided into three groups:

direct water injection (DWI), humidification of inlet air (e.g. Humid

Air Motor (HAM)) and oil-water emulsion. At DWI, a water jet is

injected simultaneously with the fuel towards the combustion flame

(Prior et al. 2005). NO

emissions

to be so low that installations of cleaning technologies are necessary.

There is a range of water-based technologies available and together

with exhaust gas recirculation (EGR) and the selective catalytic

reduction (SCR) technique, these are likely to constitute a main part

of the installations on ships susceptible to Tier III. Tier III introduces

emission limits that are not to be exceeded for low engine loads, which

may cause challenges to both the EGR and SCR technologies

(International Maritime Organization 2009).

X formation is reported to be reduced by

approximately 50% without an increase in fuel consumption (Entec

UK Limited et al. 2005; Prior et al. 2005). Some technologies humidify

the inlet air by evaporated water and one example of this is the Humid

Air Motor (HAM) technology. These technologies are sometimes

referred to as fumigation technologies. The HAM technique uses sea

water and is unique in this aspect. HAM installations are reported to

achieve a 70% NOX reduction (Riom et al. 2001; Entec UK Limited et

al. 2005), while other fumigation techniques have reached 30-60%

reductions (Prior et al. 2005). The third water-based technique consists

of letting water in oil emulsion replace the oil as fuel. A 20-25%

reduction of NOX emissions has been estimated (Sørgård et al. 2001),

49

but this figure is highly dependent on the water/oil ratio (Prior et al.

2005). All water-based technologies involve a certain risk of H2SO3

None of the water-based technologies will be able to reduce NO

formation, which leads to corrosion when it sticks to the walls of the

exhaust system and engine and the technologies can influence the

specific fuel consumption (Entec UK Limited et al. 2005; Ghojel et al.

2006).

X

to Tier III levels. As a consequence, combinations of water-based

technologies and EGR are being developed at the engine

manufacturer MAN Diesel & Turbo. Wärtsilä are similarly developing

EGR systems for their engines to be used in combination with other

techniques. EGR cools and re-circulates a portion of the exhaust gases

to the combustion chamber, which increases the heat capacity of the

cylinder gases and lowers the oxygen level, thus leading to lower

combustion temperatures and lower NOX

The NO

emissions. The reason that

the technique is not yet common on board ships is that combustion of

HFO produces large amounts of particles and sulphur compounds in

the exhausts, causing soot deposits and corrosion. The gases cannot be

directed back to the cylinder without prior cleaning (Sørgård et al.

2001; Entec UK Limited et al. 2005). In order to fit the equipment on a

ship burning HFO, an extra device to scrub the recirculated gas is

needed. Another potential solution is to use low sulphur fuel and a

filter that traps particles (Henningsen and Aabo 2007).

X reduction efficiency of EGR depends on the amount of

recirculated gas. Larger fractions of exhaust gas in the cylinder give

greater reductions but increased smoke formation and fuel

consumption. According to Goldsworthy, 69% NOX reduction at 28%

EGR and 22% NOX reduction at 6% EGR has been reported by

engine manufacturers (Goldsworthy 2002). The function of the EGR

is influenced by the engine load; the recirculated portion of gases at

reduced loads is less CO2 dense than at operations at full speed when

both the turbo charger efficiency and the fuel injection are high

(Larsson 2010; STT Emtec Emission and Engine Technology 2010).

50

Selective Catalytic Reduction (SCR) is a NOX abatement techno-

logy installed on approximately 300 marine engines in 2006 (Lövblad

and Fridell 2006). The exhaust gas is treated with urea that reacts with

NOX to form N2, CO2 and water. The reaction takes place in an SCR

reactor that contains ceramic catalyst elements coated with metal

oxides such as vanadium oxide and titanium oxide (Sletnes et al. 2005).

Urea production is energy demanding and the environmental tradeoffs

related to the operation of an SCR on a ship are described and

discussed in Paper IV (Andersson and Winnes 2010 in preparation).

SCRs should not be operated below 300°C. Lower temperatures lower

the efficiency of the reaction (Sletnes et al. 2005). A potential reduc-

tion of NOX

Few alternative fuels are being considered as potential substitutes

for the conventional marine fossil fuels. One option that has become

more frequently used is liquefied natural gas (LNG). LNG has

previously been used as a fuel for LNG carriers but is being

introduced in other segments of the fleet. However, the lack of

infrastructure for LNG in many ports limits the extent of the

technology’s use. Two other issues that are likely to hold back the

development of LNG use in ships are the costly engine changes on

existing ships that its use necessitates and the additional space

requirements for LNG storage (Sletnes et al. 2005). A change from

residual fuels to LNG reduces NO

exceeding 90% is accomplished when the temperatures

are 270°C to 500°C (Entec UK Limited et al. 2005; Lövblad and

Fridell 2006).

X emissions by approximately 90%

compared to traditional four-stroke diesel combustion, and it almost

eliminates emissions of SO2 and particles (Sletnes et al. 2005).

51

6 THE REGULATORY FRAMEWORK

Public opinion is expressed through laws and regulations in order to

protect people, their properties and nature from being damaged.

Environmental damage is sometimes regulated by international

conventions or protocols when the environmental effect extends

beyond national boundaries. The first international convention con-

cerning air pollution was the Convention of Long-range Trans-

boundary Air Pollution (CLRTAP) in 1979. CLRTAP regulates

damage to human health and the environment caused by

transboundary air pollution (www.unece.org 2010).

Improvements in the environmental performance of ships are to a

large extent dependent on the status of international conventions even

though several examples of national or regional incentive-based

schemes have proven successful in increasing installation rates for

exhaust gas cleaning equipment. In order to promote clean techno-

logies, a number of economic incentive systems exist that may also

regulate the discrepancies between costs associated with abatement

technologies and the externalities from air pollution. Emissions from

ships are in this sense under regulated since the external costs from air

pollution from ships have been much higher per tonne pollutant than

the corresponding abatement costs (Wang and Corbett 2007; Bosch et

al. 2009; Winnes et al. 2010 in preparation). A study by IIASA also

concluded that the abatement of emissions from ships was

considerably more cost-efficient than the abatement of emissions from

land-based sectors (Cofala et al. 2007). The thematic strategy of the

European Commission aims at 81% reduction of SO2 and 60%

reduction of NOX by 2020. The emission control costs were estimated

to be reduced by between 23 and 57% if ships were included in the

strategic scheme (Cofala et al. 2007).

52

6.1 INTERNATIONAL REGULATIONS

Following the United Nations Convention on the Law of the Seas

(UNCLOS), regulations concerning international shipping are

established with an international consensus. These regulations can

then, upon entry into force, be established as national laws by the

states that ratify them. The UNCLOS entered into force in November

1994 with the purpose to orderly regulate ocean related matters in

such fields as scientific research and commercial activities. It states a

territorial zone to be within a 12 nautical miles distance from shore

and an exclusive economic zone (EEZ) to be within 200 nautical miles

from shore. In the territorial zone, the coastal states exercise sove-

reignty while their rights in the EEZ are somewhat limited (UN 1982).

The International Maritime Organisation (IMO) is, as mentioned

previously, a UN agency with a main task to develop and maintain a

comprehensive regulatory framework for shipping (www.imo.org

2007). The IMO convention entered into force already in 1958.

Suggestions for, and adoptions of, new conventions in IMO can

involve any of the IMO member states. The entry into force of the

IMO conventions is normally conditioned by the signatures of a

specified number of member states with a specified minimum fraction

of the world fleet tonnage. When the conditions are met, the

convention enters into force for the states that have accepted it. Air

pollution is, as mentioned previously, regulated by the Annex VI of

MARPOL. The Annex regulates ship emissions of ozone depleting

substances, NOX, SOX

, volatile organic carbons from tankers, and

certain uses of incinerators (International Maritime Organization

2009). As mentioned in the introductory chapter, emission control

areas have been introduced. In these ECAs the emission limits are

lower and the adaptation to new limits occurs at a more rapid pace

than in the rest of the ocean. The scheduled limits as stated in

MARPOL Annex VI are presented in Figure 8.

53

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

0 1000 2000 3000

NO

Xem

issi

ons

g/kW

h

RPM

Tier I, 2000

Tier II, 2011

Tier III, 2016

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

2005 2010 2015 2020

Max

imum

allo

wed

sul

phur

con

tent

in fu

el (%

wt)

Year

Global

SECA

Figure 8. Limits of NOX

emissions from marine engines and limits of allowed

sulphur content in marine fuels as scheduled by MARPOL Annex VI

(International Maritime Organization 2009)

Regional conglomerations of states have been founded in so-called

Memoranda of Understandings (MoUs) on port state control in

several instances. For example, several Western European countries

and Canada are parties in the Paris Memorandum of Understanding

on Port State Control. This is an international agreement in which port

states require ships entering their ports to fulfil standards of

international conventions. The same requirements are placed on all

ships regardless of whether or not they have signed the conventions.

Similar agreements have been met in other regions of the world

(DeSombre 2006). The MoUs are powerful in keeping safety and

pollution protection standards at the level of international

conventions. Ships flying the flags of nations with records of low

compliance are frequently inspected and held in port if risks are

identified (DeSombre 2006).

It is possible for shipowners to register their ships in essentially any

country’s ship register. This option makes it possible for shipowners to

54

follow the regulations and commitments of any country and thereby

find solutions that might be beneficial economically, sometimes at the

expense of safety and environmental protection (Goss 2008). Flag of

convenience is a term used for ship registers that offer shipowners a

low cost alternative.

The use of flags of convenience became common in the 1920s when

US cruise ships were registered in Panama in order to be allowed to

serve alcohol on board. According to an estimation from the year

2000, 40% of the world’s tonnage sailed under flags that could be

classified as flags of convenience (DeSombre 2000). UNCTAD lists

ten major open and international registry fleets that held 56% of the

world’s tonnage in 2009. However, countries that traditionally have

been categorised as flags of convenience are not necessarily reluctant

to sign the recent regulations on environmental protection by IMO.

For example, Liberia, which is a register with a foundation in US

tanker ships, has signed several international treaties relevant to safe

shipment of oil due to pressure from shipowners (DeSombre 2006).

6.2 EU REGULATIONS

The European Union limits the sulphur content of marine fuel oils

used in the region in directive 2005/33/EC4. The directive states that

all passenger ships that operate in regular service to or from

community ports as well as ships that sail in the SOX

4 A directive is a legislative act of the

emission control

areas specified by the IMO should not use fuel with a sulphur content

exceeding 1.0% by July 2010. Exhaust gas cleaning equipment, such as

sea water scrubbers, can be used as long as the resulting emission

levels correspond to the levels from combustion of the specified low

European Union which requires

member states to achieve a particular result without dictating the means of

achieving that result.

55

sulphur oil provided they have no adverse effects on ecosystems. From

January 2010 onward, a 0.1% sulphur cap for marine fuel used in EU

ports and inland waterways is in effect (The European Parliament and

the Council of the European Union 2005).

6.3 NATIONAL REGULATIVE MEASURES AND

ECONOMIC INCENTIVES

National rules, besides those following the international conventions,

are limited geographically to the territorial waters along a country’s

coast and inland waterways. Several nations have implemented

incentive-based systems for emission reductions from ships that traffic

their waters, and any shipowner can voluntarily have their ships

participate in the program.

The economic incentives to manage airborne emissions from ships

basically consist of a reduction or a retroactive repayment of harbour

and fair way fees. Examples are the Green Award Foundation from

1994 in Rotterdam, the Swedish environmentally differentiated fair

way due and similar systems in the port of Vancouver in Canada and

the port of Turku in Finland (Green Award Foundation 2007; Port of

Turku /Turku Port Authority 2010; Port of Vancouver /Vancouver

Port Authority 2010). Another approach is the speed reduction

program adopted by the port of Long Beach in 2001 where ships

voluntarily reduce speed in a defined area close to shore (Alexander

2007). In Norway, a NOX

Obviously, shipowners can, on a voluntary basis, use more or less

standardised tools to profile themselves as environmentally conscious,

implement environmental management systems or join corporate

social responsibility (CSR) formations, though this would probably be

in response to customer requirements. More ship specific are the

notations on environmental performance issued by some of the

tax comprising ships in domestic traffic was

introduced in 2007 (Sjøfartsdirektoratet 2010).

56

leading classification societies (Det Norske Veritas 2000; Lloyd's

Register 2004).

An example of a tradable emission permit scheme for NOX and

SO2 inclusive of ship emissions is running in California. However, the

ships as such are participating as part of the transport chain of land-

based industries and the shipowners are not a main participant player

on this market (Harrison et al. 2005).

57

7 PRESENTATION OF STUDIES: DESCRIPTIONS OF

METHODS AND RESULTS

In addition to the short versions of the studies described in the

following paragraphs, they are also presented in the appended papers:

the measurement studies are presented in Papers I and II, the LCA

study of a ship transport with the use of a urea dependent catalyst is

presented in Paper III, the cost-benefit study of emissions from ships

in Gothenburg is presented in Paper IV, and the study on integration

of aspects of ships’ environmental performance in the ship design

process is presented in Paper V. The methods used in the research are

literature surveys, interview series, case studies and on board

measurements.

7.1 MEASUREMENT STUDIES

Emission measurements of gaseous pollutant species and particulate

matter were carried out on board two ships. One of the ships was an

11.000 dwt tanker dwt with a four-stroke main engine of 4,500 kW and

600 rpm. On this ship, the main objective was to determine potential

differences in emissions from using two different fuels: one a HFO and

the other an MGO. Emissions from the combustion of the two fuels

were measured during three steady state loads of the engines at

around 50%, 70% and 90% of maximum continuous rating (MCR),

respectively. The second ship was a ferry with four, four-stroke main

engines, each of 12,600 kW and 500 rpm. Emission measurements

were done on two of those engines with the purpose of quantifying

emissions from the main engines when leaving and approaching quay.

The data from the ferry were complemented by data from one

manoeuvring period of the tanker. In total, nine manoeuvring periods

were covered by the studies, although the collected data differed in

58

scope between the periods due to occasional problems with the

measurement equipment.

The measurements were made at decks high up in the engine room,

close to the end of the funnel. At these locations, holes were cut in the

exhaust pipes. The sampling from the exhausts and parts of the

instrument setup on the tanker is pictured in Figure 9 and Figure 10.

Figure 9. Sampling from the exhaust pipe

Figure 10. Dilution tube and parts of the equipment used for particle

measurements

59

7.1.1 FUEL SHIFT STUDY

Concentrations of gas constituents were measured continuously in the

hot exhaust. NOX, CO, CO2, O2, total HC, and SO2

The two fuels used on the tanker comprised a HFO with 1.6%

sulphur content and a MGO with 0.03% sulphur content. It was found

that besides its effect on SO

were monitored.

Particle emissions, which were the focus of the study, were measured

both as number concentrations and mass concentrations. The

instrument used to measure number concentrations had a detection

range from 0.30 µm to 20 µm. The potentially numerous mode with

particle diameters <0.1 µm was thus not included in the analysis.

Analyses of the fuels were carried out by an accredited laboratory.

2

The number concentrations of particles were, however, not reduced

by the fuel shift for any of the load settings that were tested. In all tests

the smallest sizes of particles were in slightly higher concentrations

from combustion of MGO than during periods with HFO combustion.

A clear numerical dominance of particles with diameters from 0.30 µm

to 0.40 µm was observed for both fuels. It is likely that the highest

number concentrations comprise particles of even smaller diameters.

emissions, the fuel type had a large effect

on the particle mass concentrations. The combustion of MGO reduced

the mass of particles to approximately half of what was seen at HFO

combustion. As less sulphur is present, less sulphate containing

particles form. In addition, the ash content is generally significantly

higher in the heavy fuel oils, which reduces the number of condensed

mineral species around which particles may form. A third explanation

is the likelihood of a higher content of poly aromatic hydrocarbons in

the heavy fuel oil, which might increase soot formation.

Average PM emission factors for HFO and MD were calculated

after combining the results from these observations with previously

published values from refereed journals and where the measurements

followed the ISO standard 8178. Emissions from combustion of heavy

fuel oil were concluded to be 1.34 g/kWh with a standard deviation of

60

0.78 g/kWh. The average particle emission factor for combustion of

marine distillates was concluded to be 0.33 g/kWh with a standard

deviation of 0.15 g/kWh. The respective average sulphur contents of

the fuels in these studies were 1.89% for HFO and 0.21% for MD.

There is a dependence of the emission factor on engine type and

engine load that was not considered in the recommended average

emission factors due to the low amount of data available. The PM

emission factors from measurements with fuels that were high in

sulphur were almost exclusively from slow speed diesels. The fact that

the data represented several different engine loads was another factor

that made conclusive remarks difficult.

There is a potentially low generality of results when only a few

objects are included in a study. The data from the study were validated

by comparison to previous studies. The results from this study were in

the range of previous values of emission factors and particle number

concentrations.

Paper I gives further details on the methods and results from these

measurements.

7.1.2 MANOEUVRING STUDY

The other component of the emission measurements were aimed at

determining emissions during manoeuvring in and out of harbour. The

focus was once again particle emissions, but this time also on NOX

The number concentrations of particles (mainly particles with

diameters of 0.30-0.40 µm) were clearly elevated during the

manoeuvring periods. Even after calculations to a per hour basis, the

number concentration of particles in the exhausts appeared higher

than during normal operations. A distinct peak in concentration,

which to 76-79% consisted of particles with diameters 0.30-0.40 µm,

was observed every time the engine was started and similarly at engine

shut-down. Once again, 0.30 µm represent the lower detection limit of

emissions.

61

the instrument. No significant differences in number concentrations

were observed between ships approaching port and ships leaving port.

Standard deviations for these particle concentrations varied from 26%

to 56% around the average value in the seven manoeuvring periods

covered by the measurements. This is inclusive of the peak

concentrations at the engine start-up and shut-down. At constant load

during cruising, the standard deviations never exceeded 13% of the

average value.

The SCRs installed on the ferry reduced the NOX emissions at

cruising speed conditions by 89%. When the SCRs were not operated,

the NOX emissions during manoeuvring were lower than during

cruising operations. NOX

Details on this study are presented in Paper II.

levels fluctuated during manoeuvring.

7.2 IMPACT ASSESSMENT STUDY OF UREA FOR SCRS ON

SHIPS

This impact assessment study is a change-oriented life cycle

assessment that estimates the effect on environmental impact from

using or not using a selective catalytic reduction system on board a

ship. Emission data from previous measurements (Cooper 2001) on

one ship with an SCR system in operation and another one without

any abatement technology installations were used to represent

emissions from ship operation. The data gathered from the activities

involved in urea production and the transport of urea was related to 1

kWh of propulsion energy from the engine and added to the emission

data from the ship with SCR.

Most data on energy use and emissions from the production of urea

were collected from reports and personal contacts with manufacturers,

which is not an unusual method in LCA practice.

The data from the inventory were used in an impact assessment in

which they were grouped into impact categories (classification), and

the respective and total impact potentials of the studied pollutants

62

were calculated (characterisation). All the assumptions made and a

more thorough description of the method can be found in Paper III

(Andersson and Winnes 2010 in preparation).

The urea is produced in an energy-intensive process in which

natural gas and coal are common energy sources. Although this

increases the global warming potential related to transport with SCR,

the results from the LCA study point in favour of using SCR on ships.

All impact categories (photo oxidant formation, acidification,

eutrophication and human toxicity) except global warming potential

are substantially lower when using the SCR as compared to the

alternative without abatement measures. The global warming

potential, on the other hand, is higher when the SCR is used. The

transport of urea was shown to have very little influence on the results,

regardless of its origin.

7.3 COST BENEFIT ANALYSIS (CBA) STUDY

In order to estimate potential benefits and costs related to policy

options for the reduction of emissions to air from ships, a case study of

emissions of NOX, SO2 and PM from the 8,500 ships calling

Gothenburg in 2008 was conducted. The choice of pollutants was a

consequence of the fact that NOX and SO2

The inventory is conducted with a bottom-up approach which

estimates emissions based on calculations of the activity and

consequent energy consumption of each individual ship within the

geographical and temporal limits of the study. For an inventory of

emissions on a local scale, the information on energy use by ships will

by necessity be based on assumptions or specific information on the

included ships, as opposed to global inventories where fuel sales

statistics can provide information that enables top-down approaches.

were targeted by the

studied regulative initiatives, and that PM is considered to be

significantly reduced by regulations on the sulphur content of fuels.

63

During the process of calculating the total emission, estimates and

generic values were used in combination with very site-specific data.

The site specific data were ship calls, ship main engine power and time

at berth to name three significant factors. Details on the data sources

are found in Paper IV (Winnes et al. 2010 in preparation).

The total emissions were approximately 4,300 tons of NOX, 0.3 tons

of PM and 1.7 tons of SO2

Reductions in emissions of NO

. Around 55% of all emissions occur while

the ship is at berth in a ‘base’ scenario. Manoeuvring emissions

account for approximately 18-19%, and the ‘at sea’ emissions

correspond to 27%. The emissions from ‘at sea’ depend on the chosen

geographical limit from which point emissions are considered to reach

the city.

X, SO2

The use of a monetary evaluation method for assessing the impacts

of emissions has the benefit of making the societal costs comparable to

costs for reducing or eliminating the emissions at the source. When

applying the evaluation model on a local scale, the dispersion of the

pollutants are essential to consider. In this study, pre-defined values of

damage related to the emitted mass of different pollutants are used.

These factors are country specific or based on the population of large

cities and contain information from dispersion models and dose-

response functions. Mainly health effects from primary and secondary

pollutants are considered.

and PM attributed to the

environmentally differentiated fair way due system, a directive limiting

the sulphur content in marine fuels and the option to connect to shore

side electricity, were evaluated. All emission reductions achieved by

installations and use of emission abatement technologies were

assessed from actual installations on board the ships.

In an analysis of the costs associated with abatement and damage to

health and the natural environment (external costs) it was established

that a complete transition to low sulphur fuels when ships are at berth

has so far been most beneficial solution from a societal point of view.

The ratio between benefits and costs ranges from a low estimate of

64

approximately 1.4:1 to a high estimate of approximately 5.9:1. This

means that in an overall analysis of the costs, the value invested in low

sulphur fuel will return 1.5 to approximately 6 times this value as

avoided external costs.

Similar ratios for the fair way due system was estimated to 1.2:1 to

3.7:1. Both options were thus beneficial from a societal perspective.

The shore side electricity was associated with negative costs, which

means that this option presented a potential win-win situation from

which both ship-owners and society in general could benefit.

The uncertainties involved in this study are described in detail in

Paper IV. Some assumptions that are believed to have a large impact

on the results and their uncertainties are related to the lack of a site

specific dispersion model, the low resolution of fuel qualities that are

used and also the emission factors, mainly for particles. The analysis of

externalities of elevated pollutant levels is presented as a plausible

range that is believed to capture the costs of the covered damage.

The generality of the values on emissions and effects are limited

since the local composition and number of calls is site specific.

However, the methodological approach and the discussion about

uncertainties are useful in other inventories on a local scale.

7.4 SHIP DESIGN METHODOLOGY STUDY

The initial study concerned the potentials of a more flexible approach

towards environmental thinking during the ship design process. The

results that can be considered as relevant in the context of subsequent

work are mainly indirect and concern the lack of data for specific

operational modes.

The options to introduce environmental aspects in the early phases

of the ship design process were investigated by interview series with

experienced ship designers and other stakeholders from the shipping

industry. The data from these interviews were treated with methods

from the systems engineering discipline. For further details the reader

65

is referred to the licentiate thesis published on the subject (Winnes

2005) and the appended Paper V.

66

67

8 PUTTING THE PIECES TOGETHER – ANALYSIS AND

CONCLUSIONS

The issue of reducing environmental problems that result from air

pollution from ships needs to be approached from different levels. In

this thesis, a local approach is taken and aspects of air pollution from

ships in port cities are in focus. Particle emissions in particular are

interesting in a local context due to their potential negative effects on

health.

A high level system comprising nature, technology and society is

described as a background framework of the conducted studies. Local

differences in effects on nature from ship emissions require detailed

emission factors of certain pollutants for accurate evaluation. This

work contributes to a better understanding of fuel dependency of

particle emissions and quantifies emissions during manoeuvring in

port areas. Particles are in contrast to SOX and NOX not limited as

such in regulatory texts. Instead, decreased emission levels rely on the

reduction that occurs when SOX

Answers to the research questions introduced in chapter

emissions are abated. Specific limits

are necessary in order to control particle emissions since the

composition of particles are diverse and depend on both fuel and

engine characteristics. Up-coming strengthened emission limits within

the regulatory framework around ship emissions emphasise a need for

efficient abatement technologies that also function at low engine

loads. Judging by the cost benefit study, the air pollution in port cities

and their surroundings are much benefitted by technologies used in

the port area.

1.2 are in

the following paragraphs discussed based on results from the

conducted studies.

68

1 How will a fuel shift towards low-sulphur fuels within the maritime

sector affect emissions of particles to air?

Many measurement studies account for the abundance of sulphate

particles from combustion of the sulphur dense marine fuels (Kasper

et al. 2007; Agrawal et al. 2008; Lack et al. 2009; Moldanová et al.

2009; Murphy et al. 2009). The approach in the study that was

conducted during the work for this thesis was to measure emissions of

particles on board a ship. In addition, two fuel qualities were used in

the same engine, each fuel during three different steady state engine

loads. This approach was beneficial for comparison of emissions from

the different fuels since all effects on particle emissions could be

attributed to the fuel shift.

It could be concluded from the conducted study, and in

consideration of related published literature, that the particulate mass

from marine engines will be reduced by a shift to low sulphur fuels.

However, the particle formation is also related to the fuel ash content

and the content of aromatic compounds and asphaltenes in the fuel,

and all of those are generally reduced by the same fuel shift. It was

also concluded that further studies on number concentrations of

particles from combustion of different fuel types are needed in order

to be able to accurately conclude on the potential damage caused by

particle emissions to air from ships.

2 What are the emissions of NOX

and particles during ships’

manoeuvring phases?

The reasoning preceding the question concerns four factors: first, the

increasing awareness of health issues related to particle levels in the

atmosphere; second, the regulations on emissions to air from ships,

which cover NOX directly but treat PM only as an effect from the

reduction of sulphur in fuels; third, technologies for NOX reduction

that are less efficient during manoeuvring; and lastly, the lack of

69

available data from this operational mode, which is contradictory to

the fact that manoeuvring often occur in populated areas.

The size distribution from the manoeuvring periods was measured

on three medium speed four stroke engines. Two of those were of the

same make and model. All measurements indicated that the small

sized particles were more abundant during manoeuvring operations

compared to operations at cruising speed. Similar to what is stated in

the answer to research question 1, more studies on the subject are

needed to confirm these observations.

The NOX emissions from one ship were abated by SCR during the

operations ‘at sea’. The result was that, for this particular journey,

during two manoeuvring periods of 25-30 minutes each approximately

30 kgs of NOX were emitted compared to approximately 45 kgs

emitted during the ‘at sea’ mode, which lasted 2 h 30 minutes. The

reduction efficiency of the SCR results in low emissions during the ‘at

sea’ mode, but these results imply a need to find effective abatement

techniques that operate at low exhaust temperatures. In the light of

the MARPOL Tier III regulations on NOX

-emissions, a development

of technologies in this direction may be necessary.

3 Which aspects need extra attention in emission inventories on a local

level and how should these aspects be treated?

An appropriate answer to this question needs to be based on an

evaluation of the effects caused by the emissions. The inventory of

emissions in the port of Gothenburg and the results from the cost

benefit study were used to answer this issue. The question was thus

approached from different directions: the health effects and a limited

number of environmental effects that are caused by ship emissions to

air in a port city were evaluated; results from the measurement studies

were used to provide information on the amounts of emissions during

manoeuvring; and inconsistency in emission factors for the pollutants

were studied.

70

An evaluation of air pollution caused by ships requires accurate

emission factors. It has often been said that ships are individuals. This

makes generic factors on pollutant emissions related to engine work or

fuel consumption uncertain. The emission factors are strong contri-

buting factors to uncertainties in local emission inventories.

The issue of particle reduction is urgent considering the amounts of

particles emitted from ship engines and the damage they cause to

human health. The elevated numbers of small size particles emitted

during the manoeuvring operations should be considered when the

health effects from ship emissions are assessed. All air quality

guidelines that have been examined in the line of this work refer to

mass of particulate matter. Characteristics of particle emissions

referring to number concentrations and toxic content, to name two

examples, are likely more descriptive than mass of particles as a means

of assessing impact on health.

Advanced modelling on plume chemistry and weather conditions

are required in order to make the most accurate assessments of the

fates of pollutants. No such modelling was done in the studies of

Gothenburg. The contribution of ship emissions to concentration

levels in a port city is not necessarily high even though the total

emitted amounts from ships are high. The ship plumes originate at

around 10 to 50 m height above sea level and are lifted and dispersed

over large areas. One exception can be during periods of ground

inversions, when the emissions from ships will occur below the

inversion layer. On such occasions, emissions below the inversion layer

including those from ships will be trapped in a limited volume of air.

4 What improvements in air quality and damage reduction will follow

political incentive based systems that target ship emissions?

There are several political incentives that target NOX and SO2

emissions from ships. Particle emissions are considered to be abated

by the same technologies that reduce SO2.

71

The international regulations and the various priorities of the

different member states of IMO can delay progress of environmental

regulations where investments are costly and the benefits are diffuse.

However, taking the opportunity to introduce local or regional

incentive based systems can reduce the air pollution caused by ships.

In the CBA study it was concluded that the effects from the Swedish

fair way due system and the option to connect to shore side electricity

had accomplished societal benefits equal to the EU directive that

limits sulphur concentration for ships at berth.

In October 2008, the International Maritime Organization (IMO)

agreed upon new international regulations on air pollution of NOX

from new ships (MEPC 2008), which has increased the need for

abatement technologies. Technologies that clean NOX

The downside of SCR is the energy intensive production of urea.

Considerations of the lifecycle of urea production, its transportation

and its use in an SCR installed on a ship showed higher overall

contribution to global warming potential from a case with SCR, as

expected, compared to ship operation without the use of SCR and

urea. However, the benefits from reduced acidification potentials,

photo oxidant formation, eutrophication and human toxicity were

more distinct.

from the

exhaust will be more widespread after the likely tightening of

permitted emission levels by IMO in Tier III of MARPOL Annex VI.

Two abatement technologies that are expected to be frequently used

are SCR and EGR in combination with water-based technologies.

Considering the replacement rate of old ships with newer ones that

comply with the different Tiers, it will take many years before

improved air quality resulting from this regulation is experienced.

Sulphur oxide emission levels are directly reduced by lower sulphur

contents in fuel. The mass concentrations of particle emissions are

related to the sulphur content of the fuel. However, the particle

number concentrations in the exhausts following combustion of low-

sulphur marine gasoil were observed to be on levels equal to or higher

72

than the concentrations from heavy fuel oil combustion during the

measurement campaign. This implies that although the mass of

particles in the exhausts is greatly reduced after a fuel shift to low

sulphur oils, the damage experienced by the surroundings of the ship is

not necessarily reduced.

73

9 FURTHER WORK

The contribution of this work is in line with the aim to quantify

environmental effects that emissions to air from ships may cause on a

local scale and to consider effects of technological as well as political

measures of improvement. A few of the aspects that would benefit

from further studies in order to come closer to this quantification are

listed below.

It is clear that the emission factors of particles in particular are

connected to many uncertainties and that these uncertainties need to

be reduced in order to make accurate estimates of health risks and

potential environmental effects caused by airborne emission from

ships. The particles of diameters below approximately 0.1 µm are very

rarely studied, even though it has been indicated that they are

abundant in the exhaust gases and are considered to be related to

potentially high health risks. There is thus a need for further on board

studies of particle emissions targeting particles of these size classes.

The results from the measurements of emissions from ships in

manoeuvring operations should be considered as preliminary.

Complementary studies are needed to clarify which observations from

the three engines in the study are of a general character and those that

were specific to the studied engines and engine types.

An impact assessment can always be done in more detail. A local

emission inventory should ideally be followed by site-specific

dispersion modelling and site specific response calculations. In order

to stay within the limits of available resources for this project, this part

was left out of the CBA and inventory study in this work. This

limitation introduced uncertainty to the results by reducing the

potential to conclude on ships’ contributions to peak concentrations of

pollutants the air masses, for example. Further efforts to conclude on

74

external cost factors suitable for the studies area should also be a

priority in a future study.

75

REFERENCES

Agrawal, H., Q. G. J. Malloy, W. A. Welch, J. Wayne Miller and D. R. Cocker Iii (2008). "In-use gaseous and particulate matter emissions from a modern ocean going container vessel." Atmospheric Environment

Alexander, G. (2007). Green Flag program, Port of Long Beach. 42(21): 5504-5510.

Amann, C. A. and D. C. Siegla (1982). "Diesel Particulates - What They Are and Why." Aerosol Science and Technology

Andersson, K. and H. Winnes (2010 in preparation). "Environmental trade-offs in nitrogen oxide removal from ship engine exhausts."

1(1): 73-101.

Submitted to the Journal of Engineering for the Maritime Environment

Andreasen, A. and S. Mayer (2007). "Use of Seawater Scrubbing for SO.

2 Removal from Marine Engine Exhaust Gas." Energy and Fuels

Arbnor, I. and B. Bjerke (1997). 2007(21): 3274-3279.

Methodology for Creating Business Knowledge

Asariotis, R., H. Benamara, J. Hoffmann, E. Núñez, A. Premti, Valentine and V. Vincent (2009). REVIEW OF MARITIME TRANSPORT 2009. New York and Geneva, United Nations Conference on Trade and development (UNCTAD).

, Sage Publications Inc.

Ashmore, M. R. (2005). "Assessing the future global impacts of ozone on vegetation." Plant, Cell & Environment

Baumann, H. and A.-M. Tillman (2004). 28(8): 949-964.

The Hitch Hiker's Guide to LCA

Beirle, S., U. Platt, R. von Glasow, M. Wenig and T. Wagner (2004). "Estimate of nitrogen oxide emissions from shipping by satellite remote sensing."

. Lund, Studentlitteratur.

Geophysical Research Letters

Bickel, P., R. Friedrich, A. Burgess, P. Fagiani, A. Hunt, G. De Jong, J. Laird, C. Lieb, G. Lindberg, P. Mackie, S. Navrud, T. Odgaard, A. Ricci, J. Shires and L. Tavasszy (2006). HEATCO - Developing Harmonised European Approaches for Transport Costing and Project Assessment - Proposal for Harmonised Guidelines, IER, Germany.

31(L18102).

Borken, J., H. Steller, T. Merétei and F. Vanhove (2007). "Global and Country Inventory of Road Passenger and Freight Transportation: Fuel Consumption and Emissions of Air Pollutants in Year 2000." Transportation Research Record: Journal of the Transportation Research Board

Bosch, P., P. Coenen, E. Fridell, S. Åström, T. Palmer and M. Hollan (2009). Cost Benefit Analysis to Support the Impact Assessment accompanying the revision of Directive 1999/32/EC on the Sulphur Content of certain Liquid Fuels, AEA Technology.

2011(-1): 127-136.

Bowman, C. T. (1973). Kinetics of Nitric Oxide Formation in Combustion Processes

Bowman, C. T. (1975). "Kinetics of pollutant formation and destruction in combustion."

. Fourteenth Symposium (International) on Combustion

Progress in Energy and Combustion ScienceBryman, A. (2001).

1(1): 33-45. Samhällsvetenskapliga metoder

Buhaug, Ø. (2010). "Personal communication regarding "Drivstoffunderøkelsen 2006"."

, Liber ekonomi (Oxford University Press).

Buhaug, Ø., J. J. Corbett, Ø. Endresen, V. Eyring, J. Faber, S. Hanayama, D. S. Lee, D. Lee, H. Lindstad, A. Z. Markowska, A. Mjelde, D. Nelissen, J. Nilsen, C. Pålsson,

76

J. J. Winebrake, W. Q. Wu and K. Yoshida (2009). Second IMO GHG study 2009. London, UK, International Maritime Organization (IMO).

Buhaug, Ö., H. Flögstad and T. Bakke (2006). MARULS WP3, Washwater Criteria for sea water exhaust gas SOx

Chen, G., L. G. Huey, M. Trainer, D. Nicks, J. Corbett, T. Ryerson, D. Parrish, J. A. Neuman, J. Nowak, D. Tanner, J. Holloway, C. Brock, J. Crawford, J. R. Olson, A. Sullivan, R. Weber, S. Schauffler, S. Donnelly, E. Atlas, J. Roberts, F. Flocke, G. Huebler and F. Fehsenfeld (2005). "An investigation of the chemistry of ship emission plumes during ITCT 2002."

scrubbers. Trondheim, MARINTEK.

Journal of Geophysical Research, Atmospheres

Cofala, J., M. Amann, C. Heyes, F. Wagner, Z. Klimont, M. Posch, W. Schöpp, L. Tarasson, J. E. Jonson, C. Whall and A. Stavrakaki (2007). Analysis of Policy Measures to Reduce Ship Emissions in the Context of the Revision of the National Emissions Ceilings Directive, IIASA for the European Commission, DG Environment.

110(D10): D10S90/1-D10S90/15.

CONCAWE (1998). Heavy fuel oils. Brussels. Cooper, D. (2003). "Exhaust emissions from ships at berth." Atmospheric Environment

Cooper, D. and T. Gustavsson (2004). Methodology for calculating emissions from ships: 1 Update of emission factors, Swedish Environmental Research Institute ordered by Swedish Environmental Protection Agency: 45.

37: 3817-3830.

Cooper, D. A. (2001). "Exhaust emissions from high speed passenger ferries." Atmospheric Environment

Cooper, D. A., K. Peterson and D. Simpson (1996). "Hydrocarbon, PAH and PCB emissions from ferries: A case study in the Skagerak-Kattegatt-Öresund region."

35(24): 4189-4200.

Atmospheric EnvironmentCorbett, J. J. and P. Fischbeck (1997). "Emissions from Ships."

30(14): 2463-2473. Science

Corbett, J. J., P. S. Fischbeck and S. N. Pandis (1999). "Global nitrogen and sulfur inventories for oceangoing ships."

278(5339): 823-824.

Journal of Geophysical Research

Corbett, J. J. and H. W. Koehler (2003). "Updated emissions from ocean shipping."

104(D3): 3457-3470.

Journal of Geophysical ResearchCorbett, J. J., J. J. Winebrake, E. H. Green, P. Kasibhatla, V. Eyring and A. Lauer

(2007). "Mortality from Ship Emissions: A Global Assessment."

108(D20).

Environ. Sci. Technol.

Dalsøren, S. B., M. S. Eide, O. Endresen, A. Mjelde, G. Gravir and I. S. A. Isaksen (2009). "Update on emissions and environmental impacts from the international fleet of ships: the contribution from major ship types and ports."

41(24): 8512-8518.

Atmospheric Chemistry and Physics

Davis, D. D., G. Grodzinsky, P. Kasibhatla, J. Crawford, G. Chen, S. Liu, A. Bandy, D. Thornton, H. Guan and S. Sandholm (2001). "Impact of Ship Emissions on Marine Boundary Layer NO

9(6): 2171-2194.

X and SO2 Distributions over the Pacific Basin." Geophysical Research Letters

De Meyer, P., F. Maes and A. Volckaert (2008). "Emissions from international shipping in the Belgian part of the North Sea and the Belgian seaports."

28(2): 235-238.

Atmospheric Environment

Deniz, C. and A. Kilic (2010). "Estimation and Assessment of Shipping Emissions in the Region of Ambarli Port, Turkey."

42(1): 196-206.

Environmental Progress & Sustainable Energy

Derwent, R. G., D. S. Stevenson, R. M. Doherty, W. J. Collins, M. G. Sanderson, C. E. Johnson, J. Cofala, R. Mechler, M. Amann and F. J. Dentener (2005). "The

29(1): 107-115.

77

Contribution from Shipping Emissions to Air Quality and Acid Deposition in Europe." Ambio

DeSombre, E. R. (2000). "Flags of Convenience and the Enforcement of Environmental, Safety, and Labor Regulations at Sea."

34(1): 54-59.

International PoliticsDeSombre, E. R. (2006).

37: 213-232. Flagging Standards: Globalization and Environmental, Safety

and Labor Regulations at SeaDet Norske Veritas (2000). Rules for Classification of Ships Newbuildings, Special

Equipment and Systems Additional Class, Part 6 Chapter 12 : Environmental Class. DNV, DNV.

, MIT Press.

Dore, A. J., M. Vieno, T. Y.S., U. Dragosits, A. Dosio, K. J. Weston and M. A. Sutton (2006). "Modelling the atmospheric transport and deposition of sulphur and nitrogen over the United Kingdom and assessment of the influence of SO2 emissions from international shipping." Atmospheric Environment

Endresen, Ø., E. Sørgård, H. L. Behrens, P. O. Brett and I. S. A. Isaksen (2007). "A historical reconstruction of ships' fuel consumption and emissions."

41: 2355-2367.

J. Geophys. Res.

Endresen, Ø., E. Sørgård, K. J. Sundet, B. S. Dalsøren, S. A. I. Isaksen, F. T. Berglen and G. Gravir (2003). "Emission from international sea transportation and environmental impact."

112.

Journal of Geophysical Research

Entec UK Limited, E. de Jonge, C. Hugi and D. Cooper (2005). Service Contract on Ship Emissions: Assignment, Abatement and Market-based Instruments: Task 2b - NO

108(D17): 4560 doi 10.1029/2002JD002898.

x

Evelyn, J. (1661, reprinted in 1999). "Fumifugium: Or, the inconvenience of the aer and smoake of London dissipated. Together With Some Remedies Humbly Proposed."

Abatement, European Commission Directorate General Environment.

Organization & EnvironmentEyring, V., H. W. Köhler, A. Lauer and B. Lemper (2005). "Emissions from

international shipping: 2. Impact of future technologies on scenarios until 2050."

12(2): 187-194.

Journal of Geophysical ResearchEyring, V., H. W. Köhler, J. van Aardenne and A. Lauer (2005). "Emissions from

international shipping: 1. The last 50 years."

110(D17306 doi:10.1029/2004JD005620).

Journal of Geophysical Research

Eyring, V., D. S. Stevenson, A. Lauer, F. J. Dentener, T. Butler, W. J. Collins, K. Ellingsen, M. Gauss, D. A. Hauglustaine, I. S. A. Isaksen, M. G. Lawrence, A. Richter, J. M. Rodriguez, M. Sanderson, S. E. Strahan, K. Sudo, S. Szopa, T. P. C. van Noije and O. Wild (2007). "Multi-model simulations of the impact of international shipping on Atmospheric Chemistry and Climate in 2000 and 2030."

110(DI17305 doi: 10.1029/2004JD005619).

Atmospheric Chemistry and PhysicsFinlayson-Pitts, B. J. and J. N. Pitts (2000).

7: 757-780. Chemistry of the Upper and Lower

AtmosphereFridell, E., E. Steen and K. Peterson (2008). "Primary particles in ship

emissions."

, Academic Press.

Atmospheric EnvironmentGhojel, J., D. Honnery and K. Al-Khaleefi (2006). "Performance, emissions and heat

release charateristics of direct injection diesel engines operating on diesel oil emulsion."

42(6): 1160-1168.

Applied Thermal EngineeringGoedkoop, M. and R. Spriensma (2000). The Eco-indicator 99 - A damage oriented

method for Life Cycle Impact Assessment - Methodology Report, PRé Consultants B.V.: 132.

26: 2132-2141.

Goldsworthy, L. (2002). Design of Ship Engines for Reduced Emissions of Oxides of Nitrogen

Goodger, E. M. (1982). "Liquid fuels for transport."

. Engineering a Sustainable Future Conference Proceedings, Hobart, IEAust.

Progress in Energy and Combustion Science 8(3): 233-260.

78

Goss, R. (2008). "Social responsibility in shipping." Marine PolicyGreen Award Foundation. (2007). "www.greenaward.org." Retrieved 2007-08-30.

32(1): 142-146.

Haagen-Smit, A. J. (1952). "Chemistry and Physiology of Los Angeles Smog." Industrial and Engineering Chemistry

Harrison, D., D. Radov, J. Patchett, P. Klevnas, A. Lenkoski, P. Reschke and A. Foss (2005). Economic Instruments for Reducing Ship Emissions in the European Union. London, NERA on assignment of European Commission, Directorate-General Environment.

44(6): 1342-1346.

Henningsen, S. (1998). Air Pollution from Large Two-Stroke Diesel Engines and Technologies to Control It. Handbook of Air Pollution from Internal Combustion Engines: Pollutant Formation and Control

Henningsen, S. (2010). mailconversation. MAN Diesel and Turbo, Copenhagen. . E. Sher.

Henningsen, S. and K. Aabo (2007). personal communication. MAN B&W Copenhagen. Heywood, J. B. (1988). Internal Combustion Engine Fundamentals

Hobbs, P. V., T. J. Garrett, R. J. Ferek, S. R. Strader, D. A. Hegg, G. M. Frick, W. A. Hoppel, R. F. Gasparovic, L. M. Russell, D. W. Johnson, C. o'Dowd, P. A. Durkee, K. E. Nielsen and G. Innis (2000). "Emissions from Ships with respect to Their Effects on Clouds."

, McGraw-Hill Book Company.

Journal of the Atmospheric Sciences

Holland, M., S. Pye, P. Watkiss, B. Droste-Franke and P. Bickel (2005). Damages per tonne emission of PM2.5, NH3, SO2, NOx and VOCs from each EU25 Member State excluding Cyprus) and surrounding seas. P. Watkiss, AEA Technology for European Commission DG Environment.

57(aug): 2570-2590.

Holland, M. and P. Watkiss (2002). BeTa Version E1:02a Benefits Table Database: Estimates of the marginal external costs of air pollution in Europe, for European Commission DG Environment by netcen.

Hulskotte, J. H. J. and H. van der Gon (2010). "Fuel consumption and associated emissions from seagoing ships at berth derived from an on-board survey." Atmospheric Environment

Institut für Energiewirtschaft und Energieanwendung and Universität Stuttgart (2005). ExternE Externalities of Energy Methodology 2005 Update. Peter Bickel and Rainer Friedrich, European Commission.

44(9): 1229-1236.

International Maritime Organization (2009). Revised MARPOL Annex VI, And NOX

International Organization for Standardization (2010). ISO 8127 Petroleum products - Fuels (class F) - Specifications of marine fuels, Fourth Edition. www.dnv.com.

Technical Code : Regulations for the preventions of air pollution from ships.

Interview series 1 (2001 - 2002). Robertsson Harry, Stena, Stefan Johansson and Christer Stålhandske, FKAB, Gustaf Carlberg and Emanuela Aresu, MacGregor, Lars Afzelius, SSPA, Per Croner, Wallenius, Ulf Holmberg, Preem, Stefan Lemieszewski, Sjöfartsverket, Mats Haglund, SSAB, Per-Olof Johansson, Vänerhamn.

Interview series 2 (2003). Fagerlund Per, Globtech Marine, Bengtsson Bo, Inmar , Andersson Leif, Kockums Engineering, Grönstrand Jan, Kockums Engineering.

Isakson, J., T. A. Persson and E. Selin Lindgren (2001). "Identification and assessment of ship emissions and their effects in the harbour of Göteborg, Sweden." Atmospheric Environment

Itano, Y., H. Bandow, N. Takenaka, A. Asayama, H. Tanaka, S. Wakamatsu and K. Murano (2005). "Daily Variation and Effect on Inland Air Quality of the Strong NOx Emissions from Ships in the Osaka Bay, Japan."

35: 3659-3666.

Terrestrial, Atmospheric and Oceanic Sciences

Jackson, A. R. W. and J. M. Jackson (1996). 16(5): 1177-1188.

Environmental Science : The natural environment and human impact, Longman Group.

79

Karle, I.-M. and D. Turner (2007). Seawater Scrubbing - reduction of SOX

Kasibhatla, P., H. Levy II, W. J. Moxim, S. N. Pandis, J. J. Corbett, M. C. Peterson, R. E. Honrath, G. J. Frost, K. Knapp, D. D. Parrish and T. B. Ryerson (2000). "Do emissions from ships have a significant impact on concentrations of nitrogen oxides in the marine boundary layer."

emissions from ship exhausts. Göteborg, Dept of Chemistry, Göteborg University for the Alliance for global sustainability (AGS).

Geophysical Research Letters

Kasper, A., S. Aufdenblatten, A. Forss, M. Mohr and H. Burtscher (2007). "Particulate Emissions from a Low-Speed Marine Diesel Engine."

27(15): 2229-2232.

Aerosol Science and Technology

King, D., M. Bradfield, P. Falkenback, T. Parkerton, D. Peterson, E. Remy, R. Toy, M. Wright, B. Dmytrasz and D. Short (2001). Environmental classification of petroleum substances - summary data and rationale. Brussels, CONCAWE.

41(1): 24 - 32.

Kley, D., M. Kleinmann, H. Sanderman and S. Krupa (1999). "Photochemical oxidants: state of the science." Environmental Pollution

Kuiken, K. (2008). 100(1-3): 19-42.

Diesel Engines I, for ship propulsion and power plantsLack, D. A., J. J. Corbett, T. Onasch, B. Lerner, P. Massoli, P. K. Quinn, T. S. Bates, D.

S. Covert, D. Coffman, B. Sierau, S. Herndon, J. Allan, T. Baynard, E. Lovejoy, A. R. Ravishankara and E. Williams (2009). "Particulate emissions from commercial shipping: Chemical, physical, and optical properties."

.

Journal of Geophysical Research-Atmospheres

Larsson, D. (2010). MAN Diesel & Turbo. Copenhagen. 114.

Lauer, A., V. Eyring, J. Hendricks, P. Jöckel and L. U. (2007). "Global model simulations of the impact of ocean-going ships on aerosols, clouds, and the radiation budget." Atmospheric Chemistry and Physics

Lawrence, M. G. and P. J. Crutzen (1999). "Influence of NOx emissions from ships on tropospheric photochemistry and climate."

7: 5061-5079.

NatureLee, D., L. Lim, V. Eyring, R. Sausen, Ø. Endresen and H.-L. Behrens (2006).

402(6758): 167-170. Radiative

forcing and temperature response from shippingLighty, J. S., J. M. Veranth and A. F. Sarofim (2000). "Combustion aerosols: Factors

Governing Their Size and Composition and Implications to Human Health."

. TAC-conference, Oxford, UL.

Journal of the Air & Waste Management Association

Lloyd's Register (2004). Rules and Regulations for the Classification of Ships, Other Ship types and Systems, Part 7 Chapter 11 : Arrangements and Equipment for Environmental Protection. L. s. Register, Lloyd's Register.

50(September): 1565-1618.

Lu, G., J. R. Brook, M. R. Alfarra, K. Anlauf, W. R. Leaitch, S. Sharma, D. Wang, D. R. Worsnop and L. Phinney (2005). "Identification and characterization of inland ship plumes over Vancouver." Atmospheric Environment

Lucialli, P., P. Ugolini and E. Pollini (2007). "Harbour of Ravenna: The contribution of harbour traffic to air quality."

40 (2006): 2767-2782.

Atmospheric EnvironmentLyyränen, J. (2006). Particle formation, deposition, and particle induced corrosion in

large scale medium-speed engines.

41(30): 6421-6431.

Physical Chemistry and Electrochemistry

Lyyränen, J., J. Jokiniemi and E. Kauppinen (2002). "The effect of Mg-based additive on aerosol characteristics in medium-speed diesel engines operating with residual fuel oils."

. Espoo, Helsinki University of Technology/VTT. Doctor of Science in Technology.

Aerosol ScienceLyyränen, J., J. Jokiniemi, E. I. Kauppinen and J. Joutsensaari (1999). "Aerosol

Characterisation in Medium-speed Diesel Engines Operating with Heavy Fuel Oils."

33: 967-981.

Journal of Aerosol Science 30(6): 771-784.

80

Lövblad, G. and E. Fridell (2006). Experiences from use of some techniques to reduce emissions from ships, Profu and IVL.

MAN B&W Diesel (1996). Emission Control - Two stroke Low-Speed Diesel Engines. Copenhagen.

Marr, I. L., D. P. Rosser and C. A. Meneses (2007). "An air quality survey and emissions inventory at Aberdeen Harbour." Atmospheric Environment

MEPC (2008). MEPC57 31 March to 4 April 2008. MEPC, IMO. 41(30): 6379-6395.

Michaelowa, A. and K. Krause (2000). "International Maritime transport and Climate Policy." Intereconomics

Moldanová, J., E. Fridell, O. Popovicheva, B. Demirdjian, V. Tishkova, A. Faccinetto and C. Focsa (2009). "Characterisation of particulate matter and gaseous emissions from a large ship diesel engine."

35(3): 127-136.

Atmospheric Environment

Murphy, S. M., H. Agrawal, A. Sorooshian, L. T. Padro�, H. Gates, S. Hersey, W. A. Welch, H. Jung, J. W. Miller, D. R. Cocker, A. Nenes, H. H. Jonsson, R. C. Flagan and J. H. Seinfeld (2009). "Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea."

43(16): 2632-2641.

Environmental Science & TechnologyNavrud, S. and G. J. Pruckner (1997). "Environmental valuation - to use or not to

use?"

43(13): 4626-4640.

Environmental & Resource EconomicsOttar, B. (1986). Acidification of Precipitation.

10(1): 1-26. Materials Degradation Caused by Acid

RainPaxian, A., V. Eyring, W. Beer, R. Sausen and C. Wright (2010). "Present-Day and

Future Global Bottom-Up Ship Emission Inventories Including Polar Routes."

. Washington, DC, American Chemical Society: 2-22.

Environmental Science & TechnologyPetzold, A., J. Hasselbach, P. Lauer, R. Baumann, K. Franke, C. Gurk, H. Schlager and

E. Weingartner (2008). "Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer."

44(4): 1333-1339.

Atmospheric Chemistry and PhysicsPope, C. A. and D. W. Dockery (2006). "Health Effects of Fine Particulate Air Pollution:

Lines that Connect "

8: 2387-2403.

Journal of Air and Waste Management Association

Popovicheva, O., E. Kireeva, N. Shonija, N. Zubareva, N. Persiantseva, V. Tishkova, B. Demirdijan, J. Moldanová and V. Mogilnikov (2009). "Ship particulate pollutants: Characterization in terms of environmental implication."

56(June): 709-742.

Journal of Environmental Monitoring

Port of Turku /Turku Port Authority (2010). Turku city harbour 's ship fees, waste disposal fees and passenger fees. F. Harbour Board of Authorities, www.port.turku.fi, http://www.port.turku.fi/files/attachments/charges/alusmaksutaksa_2010_sve.pdf.

11: 2077-2086.

Port of Vancouver /Vancouver Port Authority (2010). Notice of fee amendment (Fee amendment announcement January 29 2007 effective April 1 2007). V. p. Authority, www.portmetrovancouver.com.

Prior, A., H. Jääskeläinen and J. Walsh (2005). NOX

Richter, A., V. Eyring, J. P. Burrows, H. Bovensmann, A. Lauer, B. Sierk and P. J. Crutzen (2004). "Satellite measurements of NO

Emission Study: An Investigation of Water-Based Emission and Control Technologies. Ottawa, Fleetway Inc., for Transport Canada.

2 from international shipping emissions." Geophysical Research Letters

Riom, E., L.-O. Olsson and U. Hagström (2001). 31: L23110.

NOX Emission Reduction With the Humid Air Motor Concept. Cimac (International Council on Combustion Engines), Hamburg.

81

Russell, L. M., J. H. Seinfeld, R. C. Flagan, R. J. Ferek, D. A. Hegg, P. V. Hobbs, W. Wobrock, A. I. Flossmann, C. D. O'Dowd, K. E. Nielsen and P. A. Durkee (1999). "Aerosol dynamics in ship tracks." Journal of Geophysical Research

Saxe, H. and T. Larsen (2004). "Air pollution from ships in three Danish ports."

104(D24): 31077-31095.

Atmospheric EnvironmentSchrooten, L., I. De Vlieger, L. Int Panis, K. Styns and R. Torfs (2008). "Inventory and

forecasting of maritime emissions in the Belgian sea territory, an activity-based emission model."

38(24): 4057-4067.

Atmospheric EnvironmentSeinfeld, J. H. and S. N. Pandis (2006).

42(4): 667-676. ATMOSPHERIC CHEMISTRY AND

PHYSICS : From Air Pollution to Climate Change, 2nd edition

Sellden, G. and H. Pleijel (1995). "Photochemical oxidant effects on vegetation - Response in relation to plant strategy "

, A Wiley-Interscience Publication.

Environmental PollutionSIKA (2009). Värden och metoder för transportsektorns samhällsekonomiska analyser –

ASEK 4 : SIKA rapport 2009:3, Statens Institut för kommunikationsanalys (Swedish Institute for Transport and Communications Analysis),.

96(2): 280-281.

Sinha, P., P. V. Hobbs, R. J. Yokelson, T. J. Christian, T. W. Kirchstetter and R. Bruintjes (2003). "Emissions of trace gases and particles from two ships in the southern Atlantic Ocean." Atmospheric Environment

SIS (2002). 37(15): 2139-2148.

ISO14000:2002 - Svenska standarder för miljöledningSjøfartsdirektoratet (2010). Guideline on the NO

. Stockholm, SIS förlag. X

Sletnes, H., K. Skogen and A. B. Andersen (2005). Reduksjoner av NOtax.

X

Song, C. H., G. Chen, S. R. Hanna, J. Crawford and D. D. Davis (2003). "Dispersion and chemical evolution of ship plumes in the marine boundary layer: Investigation of O

i fartøyer - Tiltaksanalyse, DNV for Miljøverndepartementet.

3/NOy/HOx chemistry." Journal of Geophysical ResearchSong, S. K., Z. H. Shon, Y. K. Kim, Y. H. Kang, I. B. Oh and C. H. Jung (2010).

"Influence of ship emissions on ozone concentrations around coastal areas during summer season."

108(D4).

Atmospheric EnvironmentStipa, T., J.-P. Jalkanen, M. Hongisto, J. Kalli and A. Brink (2007). Emissions of NOX

from Baltic shipping and first estimate of their effects on air quality and eutrophication of the Baltic Sea, Finnish Institute of Marine Research, Finnish Meteorological Institute, University of Turku and Åbo Akademi University.

44(5): 713-723.

STT Emtec Emission and Engine Technology (2010). Presentation of Pre-Study Marine LP EGR.

Sørgård, E., A. Mjelde, T. Sverud and E. Ø. (2001). Technologies for reduction of pollution from ships. Oslo, DNV Research: 22.

The European Parliament and the Council of the European Union (2005). Directive 2005/33/EC of the European parliament and of the Council - as regards the sulphur content of marine fuels.

Trozzi, C., R. Vaccaro and L. Nicolo (1995). "Air pollutants emissions estimate from maritime traffic in the italian harbours of Venie and Piombino." The Science of the Total Environment

Tzannatos, E. (2010). "Ship emissions and their externalities for the port of Piraeus - Greece."

169: 257-263.

Atmospheric EnvironmentUN (1982). United Nations Convention on the Law Of the Sea, Part V Exclusive

Economic Zone.

44(3): 400-407.

Wang, C. and J. J. Corbett (2007). "The costs and benefits of reducing SO2 emissions from ships in the US West Coastal waters." Transportation Research Part D-Transport and Environment 12(2007): 577-588.

82

Wang, C., J. J. Corbett and J. Firestone (2007). "Modeling Energy Use and Emissions from North American Shipping: Application of the Ship Traffic, Energy, and Environment Model." Environ. Sci. Technol.

Warnatz, J., U. Maas and R. W. Dibble (2006). Formation of Hydrocarbons and Soot.

41(9): 3226-3232.

Combustion : 4th edition, Physical and Chemical Fundamentals, Modeling and Simulation, Experiments, Pollutant Formation

Whall, C., D. Cooper, K. Archer, L. Twigger, N. Thurston, D. Ockwell, A. McIntyre and A. Ritchie (2002). Quantification of emissions from ships associated with ship movements between ports in the European Community. Northwich, Entec UK Limited.

, Springer: 277-296.

Wijnolst, N. (1995). Design innovation in shippingWijnolst, N., T. Wergeland and w. a. f. F. Waals (1997).

, Univ. Press. Shipping

Winnes, H. (2005). Environmental Trade-offs in Ship Design. , Delft Univ. Press,. Department of Shipping

and Marine TechnologyWinnes, H. and E. Fridell (2009). "Particle emissions from ships; dependence on fuel

type."

. Göteborg, Chalmers University of technology.

Journal of Air and Waste Management Association

Winnes, H. and E. Fridell (2010). "Emissions of NOX and particles from manoeuvring ships."

59(DOI:10.3155/1047-3289.59.12.1391): 1391–1398.

Transportation Research Part D: Transport and Environment

Winnes, H., E. Fridell, S. Åström and K. Andersson (2010 in preparation). "Improved air quality and associated costs from regulations on ship emissions - case study on the Port of Gothenburg."

15(4): 204-211.

Winnes, H. and A. Ulfvarson (2006). "Environmental improvements in ship design by the use of scoring functions." Journal of Engineering for the Maritime Environment Proceedings of the IMechE Part M,

von Glasow, R., M. G. Lawrence, R. Sander and P. J. Crutzen (2002). "Modeling the chemical effects of ship exhaust in the cloud-free marine boundary layer."

220(M1): 29-41.

Atmospheric Chemistry and Physics DiscussionWorld Health Organization (2006). Air Quality Guidelines - Global update 2005,

Particulate matter, ozone, nitrogen dioxide and sulfur dioxide, WHO - World Health Organisation.

(2): 525-575.

World Health Organization (2006). WHO Air quality guidelines for particulate matter, ozone, nitrogen oxide and sulfur dioxide - global update 2005 - summary of risk assessment, World Health Organization.

Vutukuru, S. and D. Dabdub (2008). "Modeling the effects of ship emissions on coastal air quality: A case study of southern California." Atmospheric Environment

www.imo.org. (2007). "www.imo.org." Retrieved 2007-09-05, 2007, from www.imo.org.

42(16): 3751-3764.

www.unece.org. (2010). "http://www.unece.org/env/lrtap/lrtap_h1.htm." Retrieved 20100702, 2010, from http://www.unece.org/env/lrtap/lrtap_h1.htm.

Yang, D.-q., S. H. Kwan, T. Lu, Q.-y. Fu, J.-m. Cheng, D. G. Streets, Y.-m. Wu and J.-j. Li (2007). "An Emission Inventory of Marine Vessels in Shanghai in 2003." Environmental Science & Technology

Yannopoulos, P. C. (2007). "Sulfur Dioxide Dispersion and Source Contribution to Receptors of Downtown Patras, Greece."

41(15): 5183-5190.

Environmental Science and Pollution Research

Yin, R. K. (1994). 14(3): 172-175.

Case study research: design and methods

, SAGE Publications.