Motorway exhaust aerosols and their effects on epiphytic lichen populations

Anthropogenic Environmental Aerosols: Measurements and Biological Implications

DISSERTATION

submitted by

Pierre MADL University of Salzburg

Department of Material Sciences and Physics Division Physics and Biophysics

in partial fulfillment of the requirements of the degree of

Doctor rer.nat.

at the Faculty of Natural Sciences

Paris-Lodron University of Salzburg (PLUS) Austria

Supervisor:

Univ. Prof. Dr. Werner HOFMANN Materials Engineering and Physics

Department of Physics und Biophysics

Salzburg, October 2009

Anthropogenic Environmental Aerosols: Measurement and Biological Implications

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Table of Contents

Foreword …………………………………………………………………………….…… English Abstract ………………………………………………………………………….. Sommario Italiano ………………………………………………………………………... German Summary ………………………………………………………………………... Statement of Original Authorship ………………………………………………………... Acknowledgements ………………………………………………………………….……

5 6 8

10 11 13

PART I

Introduction Scope of this introductory Overview ..…………………………………… Aerosols – Historical aspects and some Definitions ……………………... Aerosol Modes and their Dynamics ……………………………………… Atmosphereic Aerosol Removal …………………………………….…… Anthropogenic Aerosols at Ground Level ……………………………….. Sources of Ground-Level Nano-Particles ………………………………... Particle Mass versus Particle Number Concentration ……………………. Why is Mass a Problem here? ……………………………………………. Aerosol Inhalability, Deposition Mechanisms and Clearance …………… Particle Deposition ……………………………………………………….. The Olfactory System – Shortcutting the Blood Brain Barrier …………... Particle Clearance ………………………………………………………… Toxikokinetics of Inhaled Aerosols ……………………………………… Current PM-Standards ……………………………………………………. Indoor Air ………………………………………………………………… Therapeutic Aerosol Applications ………………………………………... Lung Models ……………………………………………………………... Conclusions and Recommendations ……………………………………… Objectives of the present Study …………………………………………...

16 16 21 24 25 27 30 31 33 33 35 36 39 47 49 50 52 53 58

PART II

Section A

Highway Exhaust Aerosols and their Effects on Alpine Lichen Populations ………………………………………………………….. Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper …………………………………………………………………

62 64 66 68

Section B Stochastic Morphometric Model of the Balb-B/C Mouse Lung …….…… Paper …………………………………………………………………

86 88

Section C

Comparing lung deposition of ultrafine particles caused by fireworks and traffic ………………………………………………………………... Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper …………………………………... see Dissertation F.Kwasny

130 132 134


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Section D

Survey Report for the LogWin 10000 Windhager Heating Systems …….. Abstract ……………………………………………………………... Poster ………………………..……………………………………… Report (German only) ...……………………………………………..

136 138 140 142

Section E

Effects of Salt-Aerosols from a Gradierwerk on Inhalation Therapy and Ambient Aerosols ………………………………………….……….. Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper …………………………………………………………………

170 172 174 176

Section F

Analysis of Size Distribution and Related Lung Deposition in the Selsonics Ultrasonic Nebulization Chamber ………………………... Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper ………………………………………………………………… Report (interim, c/o Selsonics in German only) ……………..……... Report (interim, c/o MedicActiv in German only) ………..………...

188 190 192 194 204 230

Section G

Effects of Various Car Ventilation Settings on Size Distribution and Lung Deposition of Ultrafine Particles ……………………………... Abstract ……………………………………………………………... Poster ……………………………………………………………….. Paper …………………………………... see Dissertation F.Kwasny

264 266 268

Section H

Urban Aerosols in the City of Salzburg – Particle Concentration, Size Distribution and Air Quality Data …………………………………... Abstract ……………………………………………………………... Poster ……………………………………………………………….. Report (interim, c/o District Authority, in German only) …….…….. Paper …………………………………... see Dissertation F.Kwasny

270 272 274 276

Section I

Statistical Analysis of Urban Background Aerosols ..…..………………... Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper …………………………………………………………………

310 312 314 316

Section J

Exposure Assessment of Diesel Bus Emissions ………………………….. Abstract ……………………………………………………………... Poster ………………………………………………………………... Paper …………………………………………………………………

322 324 326 328

Section K

New Methods of Determination of Average Particle Emission Factors for two Groups of Vehicles on a Busy Road …………………………… Abstract ……………………………………………………………... Poster ……………………………………………………………….. Paper …………………………………………………………………

336 338 340 342


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Section A

Highway Exhaust Aerosols and their Effects on Alpine Lichen Populations

Conference Paper: European Aerosol Conference 2007 (Salzburg)

Refereed Journal (VDI)

Status: in press


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Highway exhaust aerosols and their effects on alpine lichen populations

E. Heinzelmann, P. Madl and W. Hofmann

Department of Materials Engineering & Physics, University of Salzburg, 5020 Salzburg, Austria

Keywords: aerosol sampling, combustion particles, lichens, size distribution, SMPS Shortly after the oil crisis in the 1970’s it was observed that incomplete combustion of fossil fuel resulted in thick grey-brown smog blankets covering the Salzach-valley in Salzburg, Austria (Hufnagel & Türk, 1998). The investigation of the net effect of airborne aerosol pollutants was studied with epiphytic lichen communities (Christ & Türk, 1981). Back then the most damaging component were SO2

- and H2S components resulting in loss of chlorophyll of the algal partner (Heber et al, 1994). With the gradual decrease of sulphur content in combustion fuel, NOX and polycyclic aromatic HC components have taken over the chemical aspects of pollutant inventory. Being readily adsorbed by nano-particles, they provide the ideal agent to induce damage to lichen communities located near polluted areas, and in particular near high-traffic areas (Kasperowski & Frank, 1989). By investigating the particle inventory, it is possible to correlate epiphytic lichen polutations with nearby aerosol line-sources like the Highway E55 (Tauernautobahn) and to estimate the potential damage to the adjacent Bluntau-valley.

Figure 1. Topographical setting of the Bluntau- valley, highway and measurement sites.

SMPS-measurements were carried out repeatedly on several days during a six-month period. Measurement times were coordinated by taking into consideration the topography and the geographical orientation of the highway, i.e., the north-south orientation of the U-shaped Salzach-valley suggested to confine the monitoring window to the early morning or evening hours of bright, sunny days. Oscillatory motions of air masses occur perpendicularly to the valley’s main orientation. The observed convective mass-flow of air driven by solar radiation and augmented by the western mountain

range fit nicely with the documented surface wind data recorded on these days. Since the morning measurements of the transect stretched from the westbound area across the highway to the eastbound area and beyond into the Bluntau-valley, the documented particle inventory confirms the translocating effect thereby exerting an additional stress-factor on lichen populations (fig.2).

Figure 2. Size distributions of exhaust particles near Highway E55 (Tauernautobahn).

In conclusion, this investigation documents that particles from traffic emissions are translocated across the sound-protective barriers of the highway into the adjacent Bluntau-valley. This is obviously sufficient to negatively affect lichen populations as far as 500 m away from the high-traffic area and confirm biomonitoring investigations carried out almost 20 years ago (Kasperowski & Frank, 1989). Heber, I., Heber, W., & Türk R. (1994). Die

Luftqualität in der Stadt Linz (Oberösterreich, Österreich) von Oktober 1990 bis Oktober 1991 festgestellt anhand von Flechtenexponaten. Naturk. Jahrb. Stadt Linz, 37-39, 491-552 (in German).

Christ, R., & Türk, R. (1981). Die Indikation von Luftverunreinigungen durch CO2-Gaswechsel-messungen an Flechtentransplantaten. Mitt. Forstl. Bundesversuchsanstalt, 137, 145-150 (in German).

Hufnagel, G., & Türk R. (1998). Sauteria, 9 (IAL3-Proceedings, 281-288.

Kasperowski, E., & Frank, E. (1989). Boden- und Vegetationsuntersuchungen im Bereich der Scheitelstrecke der Tauernautobahn. Umweltbundesamt Wien (Hrsg.), 1-126 (n German).


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Department of Materials Engineering & Physics – Division of Physics and Biophysics- Working Group of Radiation and Environmental Biophysics,

University of Salzburg, A-5020 Salzburg, Austria

Highway Exhaust Aerosols and Their Effects on Alpine Lichen Populations

E. Heinzelmann, P. Madl, W. Hofmann

ReferencesChrist, R. & Türk R. (1981): Die Indikation von Luftverunreinigungen durch CO2-Gaswechselmessungen an Flechtentransplantaten. Mitt. Forstlichen Bundeslehranstalt 137: 145-150. Ellenberg, H. et al. (1992): Zeigerwerte von Pflanzen in Mitteleuropa. Scripta Geobotanica 18. Göttingen: Goltze. 2nd ed. 258 pp. Hofmann, W. (2005): Aerosole – Physik der Luftverschmutzung. Lecture script. University of Salzburg. Kasperowski, G. & Frank E. (1989): Boden- und Vegetationsuntersuchungen im Bereich der Scheitelstrecke der Tauernautobahn. Umweltbundesamt Wien 15: 1-126. KRdL Kommission Reinhaltung der Luft (2007): Stickstoff und die Wirkungen auf die Vegetation. KRdL-Schriftenreihe 37. 159 pp. Masuch, G. (1993): Biologie der Flechten. Heidelberg: Quelle und Meyer. 411 pp. Nimis, P.L. (ed.) (2002): Monitoring with Lichens – Monitoring Lichens. Dordrecht: Kluwer Academic Publishers. 408 pp. Wirth, V. (1995): Flechtenflora: Bestimmung und ökologische Kennzeichnung der Flechten Südwestdeutschlands und angrenzender Gebiete. Stuttgart: Ulmer. 2nd ed. 661 pp. ZAMG Zentralanstalt für Meteorologie und Geodynamik: Klimatographie von Salzburg. Kurzfassung. (2007): Erstellt im Auftrag der Salzburger Landesregierung, Salzburg, AUT.

http://www.salzburg.gv.at/themen/nuw/umwelt/umwelt-publikationen/klimaatlas.htm.

In particular, higher aerosol concentration results in lower species diversity by damaging the thalli of the lichens (Nimis, 2002). Therefore, measurement sites in close proximity to the E55 display a distinctive absence of species otherwise found in more pristine areas of similar geo-botanic character (Masuch, 1993). Additionally, lichen associations near the highway tend to change to more nitrophilous lichen associations because of a higher amount of nitrogen available due to vehicle exhaust and being in a rural setting, the prevailing agricultural activities near the motorway along with the associated wind-related relocation of fertilizer. The dramatic reduction of lichen diversity observed at all measurement sites – with none to just a few in close proximity to the motorway backs up the hypothesis that certain particle sizes are able to enter the lichen thallus through pores of the polysaccharide layer of the epicortex thereby negatively affecting the fungi and in turn the symbiotic association between the mycobiont and the photobiont (Masuch, 1993).

AcknowledgmentThe authors wish to thank to the ZAMG for their kind assistance and for providing the meteorological data.

ConclusionsThe area of the Bluntau-Valley is predestined to be influenced by solar radiation and changing wind conditions due to meso-climatical processes and the topographical setting of the valley.Measurement days in summer showed higher particle concentrations, which correlates with the peak vehicle frequencies during the summer-holiday season. Measurement sites closer to the highway produced higher concentrations as a result of the constant mixing of exhaust particles and resuspension of larger aerosol-clusters and elevated vehicle density (Hofmann, 2005). Consequently, particles are easily relocated by wind and transported over the sound-protective barriers to finally settle in neighbouring land strips. As expected, sampling sites further away and deeper within the Bluntau-Valley yielded lower particle concentrations. However, long-distance relocation of exhaust particle-loads originating from the motorway does regularly occur, as lichen-populations on exposed sites such as the remotest site surveyed (FFK-location) do reveal a suppressed species diversity. This observation correlates with those made by other authors that associate these ecological changes to excess eutrophication and an elevated pollutant load (Masuch, 1993).

AbstractThe aim of this study was to investigate the particle inventory of airborne particles in the region of the Bluntau-Valley near Golling / Salzburg to find correlations between the existence of alpine lichen communities, particularly their vitality, and the exposure to exhaust emissions of the nearby Motorway E55 (Tauernautobahn). This motorway has been fitted with 4 m tall sound-shielding barriers to reduce noise levels of nearby residential areas.The U-shaped Salzach-Valley is strongly influenced by oscillatory motions of air masses due to solar radiation and characteristic wind directions. This leads to a translocation of aerosol particles from vehicle exhaust across the sound-protection barriers and into the Bluntau-Valley. The examination of epiphytic lichen populations in this valley confirms the negative effect of vehicle exhaust pollution, displaying a strongly reduced diversity and a change in lichen communities.

IntroductionThe Bluntau-Valley was chosen for these investigations because it was found that lichen population density and diversity have decreased under the influence of airborne pollutants (Christ & Türk, 1981). Hence it was the aim of this study to correlate particle exhaust load originating from this highway to verify the assumption that highway exhausts strongly affect lichen diversity in the Bluntau-Valley area in close proximity to the motorway E55 (Ellenberg, 1992; Kasperowski & Frank, 1989).

MethodsSMPS measurements were carried out repeatedly on four days during a six-month-period from July to December 2006, to cover a wider range of prevailing meteorological conditions. However, monitoring was limited to dry days as this facilitated the dispersal of airborne particles. With regard to the prevailing wind conditions and the north-to-south orientation of the Salzach-Valley, measurement times were confined to the early morning or evening hours as this better redistributed the particle load originating from the motorway by thermal convection into or out of the Bluntau-Valley. The census of the epibiotoc lichen species abundance was performed separately and always in close proximity to the actual SMPS-measurement sites. Sampling was limited to a stem-height window of 0.5 – 2 m, considering both relative coverage on the stem and the degree of damage of the individual lichen. Statistical diversification was obtained by exdending the sampling area in concentric circles away from the SMPS-measurementt site in steps of 10m (i.e. 1-10m, 11-20m, 21-30m, 31-40m, 41-50m). At all sites an individual species list was compiled to enable comparison and species associations. Being slow-growing organisms, the census was done in spring 2007.Measurement sites used for both the census as well as for the particle inventory consisted of the following locations (seeFig. 2): Golling 35 (G35, 20 m from motorway)

Golling 77 (G77, 20 m f. motorway)Parking Area (PA, 300 m f. motorway)Kneippanlage (KA, 500 m f. motorway)Baerenhof (BH, 2500 m f. motorway)F. Ferdinand Kurve (FFK, 4000 m f. motorway).

Fig. 1: Topographical setting of the Bluntau-Valley, Salzburg, AUT

ResultsParticle concentrations decrease with increasing distance to the source, i.e. the highway E55. Figure 3 reveals the characteristic dilution gradient within the Bluntau-Valley. This observation was consistent through the sampling campaign for all of the inbound wind conditions. However, it was observed that during inbound wind directions, the half-way site (BH) yielded lower aerosol counts than the remotest site (FFK). This is no surprise as the FFK-site is approx. 90 m higher in elevation and hence much more exposed to particle loads originating from the highway than the BH-site – the latter being well protected within a coniferous forest, whereas the FFK-site is an open location with direct view to the motorway. This correlates nicely with the species diversity found at the various locations, in that a higher diversity was documented at the BH-site and a slightly lowered one of the FFK-site.

Fig. 3: Size distributions of exhaust particles originating from the Highway with predominantly easterly winds (inbound wind direction)

for the summer months of 2006.

Fig. 4: Species diversity of lichens along the Bluntau-Valley at the various locations sampled with the SMPS-instrumentation.

Fig. 2: Topographical setting of the Bluntau-Valley with measurement sites (elevation given in parenthesis) Fig. 3: Heavily damaged lichen Parmelia sulcata (Wirth, 2002) found at site G77 on a coniferous tree.

In addition it was found that days with reversed wind conditions (outbound of the Bluntau-Valley), the average particle inventory was comparable to “purified” mountain air (FFK-site: approx. 1200 particles/cm3) compared to particle loaded Salzach-Valley air measured during inbound wind conditions (FFK-site approx. 2600 particles/cm3). During the half-year measurement campaign (from July till December 2006), we further documented a 30% decrease in particle inventory on all sites due to a reduced vehicle frequency on the motorway especially in the colder months – i.e., particle number concentration is almost twice as high in summer and correlates with the peak travelling time of major EU countries. It was also noted that characteristic and yet pollutant-sensitive lichen species of this climatic zone are displaced by mainly nitrophilous species (KRDL, 2007).

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Highway Exhaust Aerosols and their Effects on Epiphytic Lichen Populations

P. Madl1, E. Heinzelmann1, W. Hofmann1, R.Türk2

Mag.Ing. Pierre Madl, Mag. Eva Heinzelmann, Prof. Dr. Werner Hofmann, Prof. Dr. Roman Türk

1Department of Materials Engineering & Physics, University of Salzburg, 2Department of Organismic Biology, University of Salzburg,

Hellbrunerstr. 34, A-5020 Salzburg, Austria

Zusammenfassung

Diese Studie untersucht einerseits das Nanopartikel-Inventar einer stark frequentierten Autobahn

und wie es in ein nahe gelegenes Seitental (Naturschutzgebiet) eingetragen wird sowie andererseits

die Zusammenhänge zwischen epiphytischen Flechten-Gemeinschaften und deren Exposition durch

diese Abgas-Aerosole. Dieses Naturschutzgebiet eignet sich für die Untersuchung insofern, da über

die vergangenen Jahrzehnte der Flechten-Bestand und dessen Vielfalt unter dem Einfluss von Luft-

Schadstoffe drastisch zurückgegangen sind [5]. Das Ziel dieser Studie war die Überprüfung der

Annahme, dass Abgas-Aerosole der angrenzenden Autobahn die Flechten-Population im Seitental

stark beeinträchtigen. Die Messungen wurden an mehreren Tagen während eines Zeitraums von

sechs Monaten von Juli bis Dezember 2006 mithilfe eines Partikel-Messgerätes durchgeführt,

welches sowohl die Konzentration als auch die Grössenverteilung dieser Aerosole erfasst und

wurden mit Luftgütedaten von der lokalen Umweltschutzbehörde ergänzt. Das Untersuchungsgebiet

weist durch seine Lage (Ost-West-Ausrichtung) und in Verbindung mit der Sonneneinstrahlung

oszillierende Luftmassen-Bewegungen auf, so dass die Verlagerung der Abgase von der senkrecht

verlaufenden Autobahn überhaupt erst stattfinden kann. Die Bestandsaufnahme des epiphytischen

Flechtenbewuchses im Seitental bestätigt die negativen Auswirkungen des Abgaseintrages und

spiegelt sich durch in eine stark reduzierte Flechtenvielfalt als auch deren Artenzusammensetzung

wider.

Schlüsselwörter: Aerosole, SMPS Messungen, Abgaspartikel & Grössenverteilung, Flechten,

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Abstract

This study investigated the particle inventory of airborne particles originating from an intensely used

Motorway that drift into a nearby valley (Nature Preserve) and to investigate correlations between

the existence of epiphytic lichen communities and the exposure to these exhaust aerosols. This

reserve was chosen because over the past decades it was found that lichen population density and

diversity have decreased under the influence of airborne pollutants [5]. Hence it was the aim of this

study to correlate aerosols originating from the adjacent motorway to verify the assumption that

exhausts strongly affects lichen diversity in proximity to a motorway. Measurements were carried

out on several days during a six-month period from July to December 2006 using a scanning

mobility particle sizer and supplemented with air-quality data from the local EPA. The area is

strongly influenced by oscillatory motions of air masses due to solar radiation and characteristic

wind directions, thereby facilitating the migration of exhaust fumes from the perpendicularly

oriented motorway system into the east-west-oriented valley. The survey of epiphytic lichen

populations in the valley confirmed the negative effect of vehicle exhaust pollution and is reflected

both in a strongly reduced diversity as well as altered lichen community composition.

Keywords: aerosols, SMPS measurements, exhaust particles & size distribution, lichens,

1. Introduction

This study investigated the particle inventory of airborne particle transport from the north-south-

oriented motorway (Tauern-Autobahn, E55) winding through the Salzach-Valley (some 35 km south

of Salzburg / Austria) and which passes the Nature Preserve (NP) of Bluntau-Valley. It was the aim

of this investigation to find correlations between the existence of alpine lichen communities, and

exposure to exhaust emissions originating from that motorway. This motorway has been fitted with

4 m tall sound-shielding barriers to reduce noise levels to nearby residential areas. However, a

reduced diffusion of exhaust-particle load due to a canyon-effect was not observed, as turbulent flow

by speeding vehicles and trucks as well as thermophoretic influences induced by solar radiation

facilitated dispersion of exhaust gases into the nearby areas [26].

1.1 Topography: The 35 km long north-to-southbound oriented U-shaped Salzach-Valley is flanked

on both sides by parallelly-oriented, tree-covered mountain-chains of moderate to higher elevations,

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which strongly influence the diurnal oscillatory motions of air masses due to solar radiation and

characteristic wind directions. On sunny days, this oscillatory motion results in a westward drift of

air-masses during the morning hours, while it settles down during midday hours, only to reverse

direction in the afternoon and evening. The site of investigation, situated at the southern end of the

Salzach-Valley, is characterized by a 4-lane Motorway (Tauern-Autobahn A10 / E55) that tunnels

through the northern pre-Alpine calcareous rocks and passes the entrance area of the NP, which

perpendicularly opens to the Salzach-Valley several kilometres westward (Figure 1).

1.2 Effects of Atmospheric Pollution: Lichens are extremely sensitive to antrophogenically

produced airborne pollutants. The sensitivity of lichens to atmospheric pollution is due to their lack

of any regulatory processes for the uptake or release of water. They absorb dissolved pollutants

along with water and evidently store them, when water evaporates. In urban areas and highly

industrialized sites, climatic factors like lowered humidity- and higher temperature-stresses likewise

suppress lichen populations. In extensively polluted areas lichens are the first organisms to

disappear. However, the most limiting factor is poor air quality. Only some species like Lecanora

or Lepraria show some resistance to such adverse conditions [19]. Airborne pollutants include

sulphur dioxide, nitrogen oxides like NO, NO2 or N2O4, fluorides, ozone, peroxyacetyl nitrate

(PAN), secondary organoc aerosols (SOA), heavy metals [1; 2; 3, 4; 10; 18; 19] and as this study

suggests airborne nano-particles that act as a carrier for some of these chemical agents.

1.3 Nature Preserve: The only residential area near the Bluntau-Valley is found at the entrance, not

far from the motorway. Past the KA-site (see Fig. 1), the parkland is pristine and uninhabited

(except for the BH-site, where a tavern offers overnight stays for visitors). The valley has a

moderate forest coverage of deciduous and coniferous trees at the entrance area (PA- & KA-sites),

whereas a densely coniferous vegetation dominates the center and the remotest parts of the valley.

The narrow valley is flanked with steep cliffs and bare rocks rising all the way up to 2000m and

more. Because of its ecological importance (according to the Flora-Fauna-Habitat regulation -

which has been later on extended by NATURA 2000-agenda of the European Union) this valley has

been declared a Nature Preserve already in the 1980s [7]. Both its unique status as a protected area

and according to previously published literature of adverse effects of airborne pollutants particularly

in alpine valleys suggest [19] - with reference to lichens as long-term bio-monitoring organisms –

that this valley represents an ideal study site to monitor airborne pollutants. Earlier investigations on

lichen populations in the adjacent Salzach Valley likewise suggest that the area is negatively

affected by the line-source like this motorway [13].

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Figure 1: Topographical setting of the Bluntau-Valley, Salzburg, AUT. The sampling sites are indicated

along with the elevation – for exact GPS-data, refer to text.

2. Materials & Methods

2.1 Measurement Sites: As shown in figure 1, the campaign involved seven sites where

measurements and lichen census have been carried out – six on the westward side of the motorway,

stretching further into the NP with only one located east of the motorway.

• Golling 35 (G33) GPS data (N 47° 35’ 23 / E 013° 09’ 16 / Altitude: 487 m) is the only site east of the

motorway. The site is approximately 20 m away from the sound-protective barrier of the

motorway. Bushes and shrubs dominate.

• Golling 77 (G77) GPS data (N 47° 35’ 22 / E 013° 09’ 13 / Altitude: 485 m) is the nearest site on the

westward side of the highway and likewise situated approx. 3 m away from the sound-

protective barriers. Bushes and shrubs also dominate vegetation there.

• The Parking Area (PA) GPS data (N 47° 35’ 17 / E 013° 09’ 07 / Altitude: 490 m) is some 300 m west

of the motorway and provides about 50 parking slots for visitors wanting to hike into the NP.

Bushes, shrubs and few trees designate the area.

• Kneippanlage (KA) GPS data (N 47° 35’ 01 / E 013° 08’ 59 / Altitude: 480 m) is already part of the

NP where visitors can make some Kneipp experiences. Distance to motorway: 500 m. End

of sealed road. Vegetation there is characterized by typical lowland tree species (e.g. Salix

sp.).

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• Baerenhof (BH) GPS data (N 47° 34’ 19 / E 013° 07’ 26 / Altitude: 510 m) is a small tavern 2.5 km

west of the E55. The area is completely surrounded by high coniferous trees and marks the

end of the gravel road.

• The Franz Ferdinand Kurve (FFK) GPS data (N 47° 34’ 08 / E 013° 06’ 37 / Altitude: 575 m)

constitutes a narrow, steep and winding gravel road accessible by 4-wheel drive only. The

sampling site is located 3.9 km west of the motorway, high above the valley tree canopy

where the steep and high mountain ranges on both sides can be best admired.

• An additional Comparative Site (CS) GPS data (N 47° 34’ 08 / E 013° 07’ 03 / Alt.: 526 m) was

selected in order to obtain additional information for a more comprehensive lichen species

list. No aerosol sampling was performed there. Distance from motorway: 3.9 km.

2.2 Measurement Days: Aerosol measurements for each of the seven sites within the NP were

carried out repeatedly on four days over a sixth month period from July to December 2006, to cover

both summer and winter conditions. The measurements were confined to the early morning hours

when the solar radiation facilitates the shift of air masses into the NP-valley (symbolized by the

spiralling wind-arrow in fig. 1). Thus, dry and sunny weather conditions were prevalent during all

sampling days as this facilitated the dispersal of airborne particles originating from the motorway by

thermal convection into (or back out of) the NP. The corresponding meteorological data have been

retrieved from local authorities [29].

Being slow-growing organisms, the census of lichen species diversity in the NP was done on a

separate occasion (May of 2007), while monitoring of EPA-relevant parameters at the motorway

where done in summer 2007 and repeated six months later for the winter-season.

2.3 Particle Inventory: Particle inventory was monitored using a Scanning Mobility Particle Sizer

(SMPS), model 5400 Grimm Aerosol Technik, composed of a medium-sized Dynamic Mobility

Analyzer (DMA) and a Condensation Particle Counter (CPC), with a scanning window covering a

range from 5.5 to 350 nm. Since this model can be operated with the built-in battery and a single

scanning cycle lasting about 4 minutes, measurements were limited to a maximum time window of

20 minutes per site, amounting to a total sampling time of about 3 hours per day to cover all six

sites.

2.4 Vehicle frequency on the Motorway: Data of vehicle frequency is registered by an induction

loop system attached to a discriminating software in order to distinguish between motorcycles,

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passenger cars, trucks, busses and other vehicles. The data are gathered continuously and are

processed and stored by the local highway administration (ASFINAG).

2.5 Pollutant inventory at the Motorway: Measurements of environmental parameters (CO, NO2,

NOX, PM10) have been provided by the Austrian EPA (Salzburger Landesregierung) – from the

monitoring Station situated in Vigaun (some 15 km north of the NP, still within the Salzach Valley).

In order to supplement the particle exhaust load originating from the motorway, simultaneous

SMPS-measurements have been carried out both during summer and winter of 2007.

2.6 Lichen as bio-monitoring Organisms: Evaluation of epiphytic lichen species and diversity was

done on tree-stems within a range of max. 10 m from the SMPS-sampling site and within a limited

stem height ranging from 0.5 m to 2 m above ground. Statistical diversification was obtained by

extending the sampling area in concentric circles away from the SMPS-measurement site in steps of

10 m (i.e. 1-10 m, 11-20 m, 21-30 m, 31-40 m, 41-50 m - for the CS-site only a quick sample within

the 1-10 m range was performed). In order to limit the extent of lichen census, tree numbers for the

consecutive circles (>10 m) have been limited to the same number of trees to match that of the

innermost census – selection of these trees has been made via a randomised pattern. We focused

only on species diversity not on relative coverage on the stem and the degree of damage of an

individual species. Following this procedure, it was possible to compile an individual species list

for each site. The documented species found along the NP have then been compared with the

species list of the adjacent National Park Berchtesgaden [25], which corresponds to the valleys

climatic framework and yields a theoretically possible species inventory.

3. Results

3.1 Environmental Parameters: The ASFINAG-data for vehicle frequency yield an average daily

vehicle number of 59185 (SD ±7381) for the summer season, while the average daily vehicle

number for the winter period amounted to 43002 (SD ±8115). About 20% of those vehicles are

diesel powered trucks and busses, while from the remaining 80% more than half the passenger cars

run likewise on diesel, with the reminder being petrol-powered [24]. The exhaust load originating

from the motorway is shown in the figure 2a & b. Interestingly, there is a much better correlation of

nitric oxides with particle number than with particle mass (PM10, <10 µm). Already other authors

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have highlighted this particular observation and attribute it to the gaseous behaviour of particles

below 1 µm in diameter [12; 23].

Meteorological evaluation underlines the differences in precipitation and wind

characteristics. Precipitation during winter was in average only one sixth the amount observed

during summer months, while wind data confirmed the assumption that a morning breeze on sunny

days was coming from the east – introducing exhaust fumes from the motorway into the NP, while a

reversed trend was observed in the afternoon.

Figure 2.a & b: Overview of the environmental parameters on the motorway during summer (above) and

winter (below) [17].

During the summer months, we further documented a 20 % decrease in particle inventory on

all sites within the NP when compared to winter data. The actual particle concentration and

corresponding size distributions observed at the motorway during a typical summer and winter day

are shown in figure 3. Although meteorological data underline that agglomeration of the particle

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during winter is delayed due to the cooler temperatures, resulting in a higher particle burden during

winter than in summer, vehicle frequency data suggest a reversed trend. With almost 60,000

vehicles per day – the result of holiday makers crossing the alps from north to south and vice versa –

the summer-frequency data are well above the daily winter-frequency of 43,000 vehicles. However,

both higher temperatures during summer facilitate agglomeration and particle growth as well as

precipitations that occur with greater intensity and frequency, during events of precipitation much

more particles are washed out near the motorway.

Figure 3: Weekday concentration averages over the size range from 5.5 - 350 nm during the summer- and

winter measurement campaign at the motorway.

Figure 4 a & b: Size distributions of exhaust particles along the various sites within the Nature Preserve.

Shown are the averages for the summer measurements (left) and winter measurements (right).

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Due to agglomeration and gravitational settling, particle concentrations decrease with increasing

distance from the motorway. Figures 4a & b reveal the characteristic dilution gradients within the

NP. These figures also reveal broader particle size spectra compared to the source-spectra sampled

directly at the motorway (see Fig. 3). The concentration shifts from smaller to larger particle

diameters is a naturally occurring process and can be used as a proxy indicator of how old an aerosol

really is. However, it was observed that during particle measurements in the NP, the half-way BH-

site, shielded by dense coniferous vegetation, yielded a lower aerosol concentration than the

remotest FFK-site. This observation becomes obvious when considering the fact that the valley at

the level of the BH-site is densely covered with tall coniferous trees. Thus, we assume that the steep

and sunlit slopes of the naked rock that flank the valley on both sides result in a morning breeze that

sucks air from the Salzach-valley into the NP. The thermally induced turbulences within this

inbound flow (symbolized as a spiralling wind-arrow in fig. 1) seem not to pass trough the dense

vegetation at this site, rather seem to drift over the treetop canopy towards the saddle height of the

FFK-site (where a summer average of 2600 particles/cm3 has been detected). According to figure

4a, the particle concentration during the summer sampling campaign is much higher than at the BH-

site (approx. 1200 particles/cm3). The winter-measurements in figure 4b supports this assumption as

the FFK-graph reveals a sharp spike around the 10 nm range that most likely can be attributed to

mid-range relocation of vehicle immission. In the same figure, the broadened BH-summer spectrum

(with a geom. mean diameter of 69 ±3 nm) versus a narrower BH-winter spectrum (GMD of 47 ±2

nm) provides further evidence of the rapidly aging traffic-aerosol during warmer temperatures while

a stagnating agglomerating effect prevails with cooler temperatures. These observations nicely

correlates with the lichen species diversity of figure 5. A higher diversity was documented at the

BH-site and a slightly lowered one of the FFK-site.

3.2 Species Diversity of Lichens: The tracheophytic nature of the NP could support a rich diversity

of phorophytes [25], however the species inventory documented within the NP was only partially

met. The epiphytic associations of the Graphidion scriptae OCHS. 1928- and the Lobarion

pulmonariae OCHS. 1928-alliances dominate due to the prevailing moist and temperate climatic

conditions within the Bluntau Valley. Trees with a smooth bark (young Acer pseudoplatanus,

Fraxinus excelsior, Fagus sylvatica) favour associations of the Pertusarietum amarae,

Thelotremetum lepadinae and Opegraphetum rufescentis. Lobarietum pulmonariae occurs only in

strongly reduced associations on well-sheltered older trees. Over the past two decades, the

cyanobacterial macrolichens like Nephroma spec., Peltigera collina, Leptogium saturninum became

very rare [14]. Thus only fragments of the Lobarietum pulmonariae association are detectable, e.g.

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Parmeliella triptophylla, Ochrolechia androgyna and Lobaria pulmonaria (very rare). Lichens

which represent the Xanthorion parietinae OCHS. 1928-associations became more frequent in the

last decade. An indication that the influence of nitrogen compounds increased over the last two

decades. It was also noted that characteristic and yet pollutant-sensitive lichen species of this

climatic zone are displaced by mainly nitrophilous species [16]. Also acodiphilous associations

(Pseudevernietum furfuraceae HIL. 1925) with the representative species Pseudevernia furfuracea

and Hypogymnia spec. largely disappeared.

Most lichen species documented occurred in well-lit places and have been found on

moderately acid sites (pH 4.9 - 5.6). Concerning nutrients, the documented species show no

homogeneous preference; their habitat can either be rich or poor in nutrients. Toxicity-tolerance of

the species listed in table 1 varies mainly from intermediate to moderately high (see [6]). From a

past census it is known that the lichens in the NP are either thriving or tend to disappear as abiotic

parameters render survivability unfavourable [14].

As shown in table 1 and figure 5, site G35 is almost devoid of any lichens – in the vicinity of

the motorway, one can literally speak of a “lichen desert”. The situation gradually improves with

increasing distance to the motorway as more species can be found. This trend is consistent all the

way through to site PA where only nitrophilous lichens occur. The slightly better finding at site

G77, compared to site G35 can be attributed to the general scarcity of lichens at those two sites; the

number of species documented was very low. Diversity gradually improves at the subsequent

locations PA, KA (with a higher amount of acidophilous species) and sites BH and FFK, which are

much farther away from this line-emitter. The slightly suppressed diversity found at the KA-site is

most likely related to its location; i.e. it is situated at the centremost-point at the entrance of the NP,

where particle loads from the motorway are funnelled through this bottleneck thereby increasing the

likelihood of aerosol-exposure under appropriate mesoclimatic conditions. The higher species

number of lichens documented at site BH is also attributable due to the species diversity of the

phorophytes. Penetrating even further into the NP, the composition changes yet again with site CS

revealing a well developed Lobarietum association prevalent on sheltered Acer trees. Both locations

(BH & CS) are well-protected and sheltered from direct aerosol exposure. Finally, spruce trees

dominate the remotest sampling site (FFK). Its elevated position enables a direct view to the

motorway and hence exposure to motor-vehicle aerosols, which is well reflected in the suppressed

species composition of the lichens found there.

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Pos Bluntau-Valley sampling site

# Occurrence of lichen species G35 G77 PA KN BH FFK CS 1 Arthonia radiata - - - - - + + 2 Calicium viride - - - - + - - 3 Candelaria concolor - - + - - - - 4 Candelariella reflexa - - - - - + - 5 Candelariella xanthostigma - - + + - - - 6 Cetrelia cetrarioides - - - - + - - 7 Cetrelia olivetorum - - - - - - + 8 Chaenotheca chrysocephala - - - - + - - 9 Cladonia coniocraea - - - - + + +

10 Cladonia fimbriata - - - - + - + 11 Evernia prunastri - - - - + - - 12 Graphis scripta - - - - - - + 13 Hypogymnia physodes - - - + + - - 14 Lecanora carpinea - - + - - - - 15 Lecanora chlarotera - - + - - - - 16 Lecidea nylanderi - - - - + - - 17 Lepraria spec. - - - - + + + 18 Lobaria pulmonaria - - - - - - + 19 Lopadium disciforme - - - - - - + 20 Melanelia elegantula - - - + - - - 21 Melanelia glabratula - - - - - + - 22 Menegazzia terebrata - - - - - - + 23 Mycoblastus fucatus - - - - - + - 24 Normandina pulchella - - - + - + + 25 Ochrolechia androgyna - - - - + - + 26 Parmelia saxatilis - - - + + - + 27 Parmelia sulcata - + + + - + + 28 Parmelia tiliacea - - + - - - - 29 Parmeliella triptophylla - - - - - - + 30 Parmeliopsis ambigua - - - - + - - 31 Pertusaria albescens - - - - + - + 32 Pertusaria amara - - - + + - - 33 Phaeophyscia orbicularis - - + - - - 34 Phlyctis argena - - - + + + + 35 Physcia adscendens - - + - - - - 36 Physcia tenella - - + - - - - 37 Platismatia glauca - - - - + - - 38 Ramalina farinacea - - - - + - - 39 Strigula stigmatella - - - - - + - 40 Xanthoria parietina + + + - - - -

Number of found species 0.7 ±0.6 2 ±0.0 9.7 ±0.6 7.4 ±1.1 18 ±1.6 10 ±1.0 16

Table 1: Lichen species found at the various measurement / sampling sites within the Bluntau-Valley; a

positive occurrence is denoted with (+) an absence with (-). The total number of species are averages,

including all five concentric sampling circles along with the corresponding standard deviations (except for

CS-site).

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Figure 5: Lichen species diversity within the NP at the associated SMPS sampling sites.

According to TÜRK & WUNDER [25], the theoretically possible number amounts to a total of

60 different lichens species that theoretically could thrive within this NP. Comparing that to the

total of 40 actually found within the NP (see table 1) provides an already gloomy picture. However,

relating this number to the maximum species number found on a given site (e.g. BH) the situation

becomes really dramatic as only 17 different species could be documented. Thus, both the numbers

as well as the species involved are well below those found in the neighbouring National Park

Berchtesgaden, which is completely shielded-off by mountain ranges.

4. Conclusion

4.1 Present study: This study showed that the NP is very suitable to evaluate the long-term effects

of anthropogenically induced airborne pollutants. The unique topographical setting of the NP, with

its distinct meso-climatical characteristics make it an ideal study site for nano-particle

investigations. Over the past decades many investigations have used particle concentrations

measurements to monitor the environment [20; 22; 27; 28], assigning SMPS measurements a

reliable status to evaluate size and concentrations of airborne nano-particles. These days, studies are

very much concerned about aerosols originating from industries and vehicle exhaust. However,

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authorities like most European EPAs predominantly rely on gravimetric parameters (e.g. PM10,

which determines the mass of particles smaller 10 µm, rather than determining the quantity of

particles in various sizes classes below 1 µm. Yet, particularly these quasi-weightless nano-particles

are known to be more hazardous to life [9; 15]. For this study, particle sizes from 5.5 nm to 350 nm

have been measured with the SMPS system – a size range not only far lower than official standards,

but with an information value much richer than a single parameter such as PM10.

Airborne particle load at and next to the motorway during summer showed higher

concentrations, which correlates with the peak holiday-traffic season of most central European

countries as they go to or return from their destinations in the south or the north respectively.

Particle load during the cooler period of the year was significantly higher compared to the warmer

season even though less vehicles have been counted on the Motorway – a phenomenon associated to

the cooler temperatures resulting in altered particle dynamics.

The examination of epiphytic lichen populations in this valley confirms the negative effect of

vehicle exhaust pollution, displaying a strongly reduced diversity and an altered lichen community

composition. Species diversity near the motorway tend to change to more nitrophilous lichen

associations – most likely the result of a higher nitrogen availability due to vehicle exhaust

(nitrogenous immissions from agricultural activity near the motorway and in the broader Salzach-

Valley are almost inexistent, thus insignificant).

Measurements further away to this line-source revealed elevated aerosol concentrations that

resulted from both constant mixing of aerosols, along with wind-associated relocation and

resuspension of larger aerosol-clusters due to dense traffic. As expected, sampling sites still further

away and deeper within the NP yielded lower particle concentrations. However, long-distance

transport of exhaust aerosols originating from the motorway must have occurred regularly, as lichen-

populations on the exposed FFK-site does show a reduced species diversity. This observation

correlates with those made by other authors that associate these ecological changes to excess

eutrophication and an elevated pollutant levels [19].

At this stage of the investigation it cannot be ruled out that the poor viability of lichens

species may also be caused by gaseous nitrogen-compounds or aerosols onto which nitric-oxides

have adsorbed onto or even nitric aerosols as a result of the photochemical interactions between

volatile organic carbon (VOC), nitric oxides (NOX) and recycled ozone (O3). However, the most

likely scenario involved, regards a dynamic interaction of all three processes combined, as

particulate nitrate is a significant component of an aged aerosol [8] with the secondary organic

aerosol (SOA) formation being intrinsically connected to both NOX and VOC [3]. Ammonium

nitrate (NH4NO3) is believed to be one of the major forms of particle nitrate found primarily in the

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large-particle mode – it can dissociate to HNO3 and HN3 [8]. The subsequent exposure to water

vapour followed by drying leads to the formation of individual microcrystalline mixture of NaNO3

and NaCl (a phenomenon most peculiar during the winter-months when dew-point suppression is

induced by salting the highway with NaCl). In addition, it was observed that re-activation of nitrates

in aerosols close to or in snow surfaces results in subsequent photochemical production of NOX.

Recycling of nitric acid in aerosols / snow surface seems to occur everywhere where snow is present

[11]. Thus, higher aerosol concentration results in lower species diversity by damaging the thalli of

the lichens [21].

4.2 Outlook: This study confirmed the dramatic trend in the reduction of lichen diversity at all

measurement sites – with none to just a few in close proximity to the motorway, which backs the

hypothesis that certain particle sizes are able to enter the lichen thallus through pores of the

polysaccharide layer of the epicortex thereby negatively affect the fungi and in turn the symbiotic

association between the mycobiont and the photobiont [19]. Because lichen lack any protective

layer against airborne substances, they are very sensitive to atmospheric pollutants. However,

questions associating lichen damage to pollutant accumulation, which they take up along with their

nutrients via diffusion, or by nano-particle exposure, which easily enter the thallus via pores in the

epicortex, can only be answered by a follow-up investigation. In the course of such a study

laboratory investigation should shed light on which part of the lichen is most affected by nano-

particles – the fungus or the algae and should also address the growth inter-dependency of fungus

and algae during nano-particle exposure and which size range affects the organism most.

5. Acknowledgments

The authors wish to thank HASLHOFER J. from the ZENTRALANSTALT FÜR METEOROLOGIE &

GEODYNAMIK (ZAMG) for his kind assistance and for providing the meteorological data.

Furthermore, KRANABETTER A. from the SALZBURGER LANDESREGIERUNG for using the EPA-data

(CO, NOX, PM10). Finally, we wish to hank BOREK H. & SCHRÖDER from the AUTOBAHNEN- &

SCHNELLSTRASSEN- FINANZIERUNGS-AG (ASFINAG) who forwarded us the vehicle frequency data

of the motorway (E55 - Tauern-Autobahn).

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Motorway exhaust aerosols and their effects on epiphytic lichen populations