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CAUSE Paper 13. Air quality

Critique of Air Quality assessments and consideration of air

quality impact of the proposed “garden community”

developments in north Essex.

Professor Stephen Peckham BSc. MA(Econ)., HMFPH Dr Ashley Mills BSc., MSc., EngD. Centre for Health Services Studies University of Kent

Summary points

The proposed plans for developing garden communities in North Essex focus on three strategic

sites. This paper reviews the proposals from an air quality perspective and concludes that the

current background assessment for air quality impacts falls short of current National Planning Policy

Framework (NPPF) requirements and planning and health guidance. The NPPF, environmental

guidance and recent National Institute for Health Care Excellence (NICE) guidance all require that

an assessment of air quality should be addressed in plan making. It is inconceivable that building

5,910 houses in the next decade, and over 40,000 in total, will not impact local air quality. However,

in the locations proposed there is no current air quality monitoring to enable full consideration of

air quality issues. The only reference to air quality in the sustainability assessment concludes –

without any detailed analysis or reference to current national policy or local data – that impacts on

air quality will be minimal or negligible.

In the proposed locations of the three garden communities current levels of fine Particulate Matter

(PM2.5) exceed World Health Organisation (WHO) recommended limits of 10µg/m3 – a level seen as

a UK objective in the Government’s 2019 Clean Air Strategy. Public Health England currently

estimate that across the three authorities that 246 annual excess adult deaths arise from PM2.5

exposure with an estimated 2,500 years of life lost. Any increase in PM has been shown by Public

Health England and the WHO to lead to a wide range of health problems and additional health and

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social care costs. Current levels of Nitrogen Dioxide are also above level of 10µg/m3 that has been

shown to lead to the permanent damage of children’s lungs.

This paper sets out:

the regulatory framework and developing national policy relating to air quality (Sections 2,

3)

identifies the health impacts of poor air quality that would be resultant from these

proposed developments (Section 4)

provides an assessment of current air quality in the development areas (Section 5)

provides an assessment of the potential impact of the developments on air quality (Section

6)

The paper concludes that the development of the three key proposed sites favoured by NEA should

be subjected to a more detailed air quality assessment. The current proposal does not meet the

requirements of NPPF paragraphs 103, 117, 122, 127, 180, 181 and 202 nor current Environmental

Impact Assessment (EIA) and NICE guidance.1-3 There is no comparison of different development

options. For example, whether more dispersed development, based on existing communities and

not focused on one narrow transport corridor, might present a more sustainable approach with a

significantly lower air quality impact.

The proposed mitigation makes claims for modal shift and public transport use that is not

supported by evidence and in places is contradicted by submissions in support of the plans. Overall

traffic assumptions, predictions of modal shift and the development of a rapid transit system in

particular, lack detail and clarity and are not based on realistic assumptions. Combined with the

current existing over capacity in road and transport networks the mitigation assumptions are

unrealistic. It is not possible to be confident that proposed mitigation is, therefore, meaningful or in

fact achievable and therefore the effectiveness of the proposed mitigation is unproven and

contrary to the recent Appeal Court ruling in Gladman Developments Ltd vs Secretary of State for

Communities and Local Government ([2019] EWCA Civ 1543).

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1. Introduction 1.1. Current proposals in the Section 1 local plans for Braintree, Colchester and Tendring Councils

set out the development of three garden communities. North Essex Garden Communities Ltd is

a company owned in equal parts by four North Essex city councils: Braintree District Council,

Tendring District Council, Colchester Borough Council and Essex County Council. It was set up

on 9th August 2016 with the goal of building three garden communities along the North Essex

A120 corridor totalling up to 43,000 homes.4 The locations and land use shapes of these

developments are illustrated in Figure 1 below.

Figure 1 - Land locations and development areas for the three proposed garden communities.

1.2. A sustainability appraisal has been prepared for this proposal by Land Use Consultants Ltd

(company number 02549296) and has produced a number of outputs.5 With regard to Air

Quality the outputs conclude variously that the overall impact will be negligible or minor with

some uncertainty, yet no formal modelling or measurement has been undertaken. The fact

that there is no impact assessment on air quality and population health. This is contrary to the

National Planning Policy Framework and current guidelines on assessing environmental and

health impacts of future development. Neither is there any comparative impact assessment

when compared with alternative development locations. It is simply not sufficient to claim, as

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these proposals do, that adhering to “garden city” principles is sufficient consideration to

ensure no air quality and health impacts given the complete lack of any relevant assessment in

the option appraisals, previous sustainability assessment and in the local plan.

1.3. The Planning Inspector has previously identified that the proposals “… generally made

optimistic assumptions about the benefits of garden communities …”, but while a number of

new assessments have been put forward by the Councils, no new analysis of air quality has

been undertaken. For example, while specific assessment has been made of trip calculations

for different sites (eg North Essex Garden Communities Access and Movement Study: EB/014)

there is no air quality modelling despite its specific potential detriment on population health.

Having opted to make revisions in line with the Inspector’s recommendation to re-submit plans

“… with any necessary revisions, after carrying out the required further work on the evidence

base and sustainability appraisal, and the relevant consultation and other procedures required

by legislation” it is unacceptable that air quality has not been assessed in the plan making

process as required by the NPPF and current planning guidance.1

2. Air quality – planning and assessment guidelines

2.1. Planning decisions by local planning authorities (District, Unitary and County Councils) are

regulated by the Town and Country Planning Act 1990 (TCPA 1990). Section 70(1) of the TCPA

1990 empowers a local planning authority to grant planning permission with or without

conditions, or to refuse it. The local planning authority is required to achieve a balance

between economic, social and environmental considerations when making a decision about a

specific proposed development. In dealing with an application, the authority is required under

section 70(2) to have regard to:

a) the provisions of the development plan, so far as material to the application;

b) any local finance considerations, so far as material to the application; and

c) any other material considerations.

2.2. Local planning authorities need to assess the potential impact of development on air quality

where relevant limits have been exceeded or are near the limit, affect population health and

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how developments may impact declared Air Quality Management Areas. As part of this

process, they are required to appropriately consider air quality, paying particular attention to:

compliance with national air quality objectives and of EU Limit Values;

whether the development will materially affect any air quality action plan or strategy;

the overall degradation (or improvement) in local air quality; or

whether the development will introduce new public exposure into an area of existing poor

air quality.

2.3. Where developments are significant in size or likely to have significant impacts, air quality is

likely to be a material consideration in the planning process and must be given due weight

when determining an application. The Town and Country Planning (Environmental Impact

Assessment) Regulations 2017 refer to air pollution as one of the considerations to be

addressed in planning applications. The regulations highlight the fact that planning authorities

need to identify, describe and assess in an appropriate manner, in light of each individual case,

the direct and indirect significant effects of the proposed development on population and

human health (4(a)).

2.4. While not all planning applications will have a significant impact on air quality, those that

involve substantial residential and commercial development could potentially have a negative

impact due to increased emissions from the developments themselves and increased traffic.

Generally, the main source of pollution is from vehicle emissions (NO2 and PM), although in

rural areas ammonia is a key contributor to particulate matter. With most developments there

is then, the potential for impacts on local air quality to occur as a result of emissions from road

vehicle trips generated by the operation of major housing or other developments. Guidance

provided by the Institute of Air Quality Management & Environmental Protection UK (EPUK)

(Ref. 8.3) provides threshold criteria for establishing when significant impacts on local air

quality may occur and when a detailed assessment of potential impacts is required.

2.5. At locations outside an AQMA, a change in light duty vehicles (LDV) (i.e. any motor vehicle with

a gross weight of 4,500 kg or less) of more than 500 per day and / or a change in heavy duty

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vehicles (HDV) (i.e. any motor vehicle with a gross weight of 4,500 kg or more) of more than

100 per day is considered to result in potentially significant impacts on air quality. At locations

within or adjacent to an AQMA, a change in LDVs of more than 100 per day and / or a change in

HDVs of more than 25 per day is considered potentially significant. The proposed garden

community developments clearly fall well within these guidelines with just one site (CBBGC)

creating a minimum of 4,000 additional cars per day and possibly in excess of 9,000 (Lawrence

Walker Limited 2019 para 2.15). Thus, it is surprising that in the Sustainability Assessment no

assessment of potential air quality impact of such a significant increase in traffic has been

conducted. The suggested sites - particularly at Marks Tey and East of Colchester have the

potential to significantly impact local air quality and there are grounds to be concerned

regarding the development along a single road corridor with the third site West of Braintree.

2.6. The NPPF highlights the importance of considering effects on air quality with planning

authorities required to take “… into account the presence of Air Quality Management Areas and

Clean Air Zones, and the cumulative impacts from individual sites in local areas.” (Para 181).

There is a more general requirement for authorities to seek:

“Opportunities to improve air quality or mitigate impacts should be identified, such as

through traffic and travel management, and green infrastructure provision and

enhancement. So far as possible these opportunities should be considered at the plan-

making stage, to ensure a strategic approach and limit the need for issues to be

reconsidered when determining individual applications. Planning decisions should ensure

that any new development in Air Quality Management Areas and Clean Air Zones is

consistent with the local air quality action plan. (ibid).

2.7. In addition, the NPPF also links air quality issues to vehicle emissions with authorities having to

also consider:

“… from the earliest stages of plan-making and development proposals, so that; …

environmental impacts of traffic and transport infrastructure can be identified, assessed and

taken into account – including appropriate opportunities for avoiding and mitigating any

adverse effects, and for net environmental gains” (Para 202(d)) and that

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“… Significant development should be focused on locations which are or can be made

sustainable, through limiting the need to travel and offering a genuine choice of transport

modes. This can help to reduce congestion and emissions, and improve air quality and

public health. …” (Para 103).

2.8. The NPPF makes it clear, a position supported by guidance (eg. The Town and Country Planning

(Environmental Impact Assessment) Regulations 2017 (SI 2017 No571)) and current best

evidence, that assessment of air quality should include both compliance with current air quality

directives but also avoid harmful health effects.1-3 The meeting of air quality directives alone

does not ensure full compliance with the NPPF. Assessment of the health impact of air quality

also meets the “well-being” duty placed on local authorities by Section 2 of the Local

Government Act 2000 (the ‘2000 Act’) allows principal local authorities in England and Wales to

do anything they consider likely to promote the economic, social and environmental well-being

of their area unless explicitly prohibited elsewhere in legislation. This Power (‘the Well-Being

Power) is intended to be all-embracing and in practice, the three objectives of economic, social

or environmental well-being have been interpreted by local authorities to encompass cultural

well-being and the promotion or improvement of the health of residents and visitors.

3. Changing national strategy on air quality

3.1. The exact future level limits of pollutants are, based on the new Clean Air Strategy (DEFRA

2019), likely to be lower than those currently in force.6 The Clean Air Strategy states that:

“We will commit to a new target for the reduction of damaging deposition of reactive forms

of nitrogen and review what longer term targets should be to further tackle the

environmental impacts of air pollution.” (p8). The strategy also sets out a commitment that

the Government will "... reduce PM2.5 concentrations everywhere, so that the number of

people living in locations above the WHO guideline level of 10 μg/m3 is reduced by 50% by

2025, compared to our 2016 baseline. Areas above the 10 μg/m guideline limit in 2025 will

have lower concentrations than today, and we will set out our plans to reduce PM2.5

concentrations even further in due course." (P30).

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3.2. Of particular relevance to the current proposal is the strategic commitment to:

"… reduce PM2.5 levels in order to halve the number of people living in locations where

concentrations of particulate matter are above10μg/m3 by 2025; We will set a new,

ambitious, long-term target to reduce people’s exposure to PM2.5 and will publish evidence

early in 2019 to examine what action would be needed to meet the WHO annual mean

guideline limit of 10 μg/m3" (P31)

3.3. The latter point is highly relevant as the areas in which the garden communities are to be

developed currently has levels of PM2.5 above WHO limits. These measurements are based on

background modelling and local levels, especially near existing busy roads are likely to be

higher. Levels in Colchester which has existing AQMAs, also has PM levels above these limits as

well as current exceedances of NO2.

3.4. Currently there is a draft Environment Bill under discussion and what shape the final pollutant

limits will take remains uncertain. However, statements by the current Secretary of State have

indicated a commitment to the previous Secretary of States environment objectives. The draft

Bill will be published in the autumn and is likely to contain new air quality limits for PM2.5 and

objectives for NO2. The Bill is also likely to include a requirement for local authorities to

specifically consider how their air quality action plans affect children and the elderly and take

additional action if necessary. This is likely to also make local authorities more likely to require

impact assessments for these more vulnerable populations as part of planning requirements.

4. Air quality and population health

4.1. Air quality impact on population health 4.1.1. The evidence on the negative health impacts of air pollution is overwhelming and our

understanding of the health problems associated with both long-term and short-term

exposure to pollutants such as NO2, PM2.5, PM10, and O3 increases every year. Guidance

published by the Town and Country Planning Association (2015) highlights air quality as one

area where public health services and professionals should influence planning decisions.

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There is no evidence that a health impact assessment has been undertaken with regard to the

proposed new road despite its proximity to current and proposed housing, pedestrians and

cyclists. The NPPF, air quality planning guidance and The Town and Country Planning

(Environmental Impact Assessment) Regulations 2017 (SI 2017 No571) all refer to the impact

of development on population and human health. Environmental Impact Assessments (EIAs)

regulations state that the assessment “… must identify, describe and assess in an

appropriate manner, in light of each individual case, the direct and indirect significant

effects of the proposed development on …… (a) population and human health;” (4(2)).

4.1.2. Despite the commitment to garden communities contributing to “healthy place making” and

promoting health and well-being the NEGC Garden Communities Charter only makes general

statements about promoting healthy lifestyles and healthy places to live.9 No health

assessment related to the proposed development has been undertaken. With regard to air

quality health impacts the modelled measurements referred to in the sustainability

assessment have only been compared with annual UK air quality objectives currently in force

and not their impact on population health. However, the potential impact on short-term

exposure and signalled changes in the 2019 National Air Quality Strategy4 - which commit to

reducing objectives for PM2.5 to the WHO limit and reduce the proportion of the population

exposed to levels above the WHO limit by 50% by 2025 - should be considered when

assessing the viability of the proposed new link road as well as the development sites. As

shown in Section 5, current PM2.5 levels are above or just below the 10µg/m3 WHO limit

already. A recent analysis by Public Health England predicted that currently across the three

local council areas 246 annual excess adult deaths arise from PM2.5 exposure with an

estimated 2,500 years of life lost.10

4.1.3. Public Health England and the National Institute for Health and Care Excellence have

published guidance, which, have helped to highlight the health impacts of air pollution with

compelling evidence of a significant impact from both short-term roadside and longer term

exposure on the burden of disease and mortality.2,3,10-13 Significant associations with hospital

admissions for a variety of respiratory and cardiovascular diseases (including ischaemic heart

disease, cerebrovascular disease and heart failure) have been found with levels of PM below

WHO limits and therefore significantly below current UK limits.14 The evidence of significant

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adverse health impacts from low levels of poor air quality is now well established with

children and older people being particularly at risk. NO2 and low level ozone (O3) are strongly

associated with respiratory and cardiovascular diseases with the effects occurring from both

short- and long-term exposure. There is strong evidence that daily (24-hour average)

exposures to PM are associated with both mortality and morbidity immediately and in

subsequent days. Repeated (multiple day) exposures may result in larger health effects than

the effects of single days.14 Both epidemiological and clinical studies have demonstrated that

sub-daily exposures to elevated levels of PM can lead to adverse physiological changes in the

respiratory and cardiovascular systems.14

4.1.4. A recent international study concluded that an increase of 10 µg/m3 of PM10 concentration

compared to the previous day, was associated with increases of 0.44% in daily all-cause

mortality, 0.36% in daily cardiovascular mortality, and 0.47% in daily respiratory mortality.

For the same change in PM2.5 concentration the mortality impacts were 0.68%, 0.55%, and

0.74% respectively.15 The associations remained significant after adjustment for other

gaseous pollutants. The results showed a consistent increase in daily mortality with increasing

PM concentration with the impact worse in areas of lower PM concentrations. In 2015, Public

Health England estimated the impact of PM2.5 levels on early death in England (the data for

Essex is shown in table 1). They estimated that across the three authorities in North Essex

that 246 annual excess adult deaths arise from PM2.5 exposure with an estimated 2,500 years

of life lost.10

Table 1: Excess mortality associated with PM

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4.1.5. A core element of any proposed development must therefore consider how further excess

deaths and years of life lost can be avoided. In particular, there should be focus on reductions

in PM levels. Any increase in PM has been shown by Public Health England and the WHO to

lead to a wide range of health problems and additional health and social care costs.10,16

4.1.6. Current levels of Nitrogen Dioxide are above levels of 10µg/m3 that has been shown to lead

to the permanent damage of children’s lungs.17 There is no local data on O3 levels but the

evidence clearly shows that levels of O3 from 80µg/m3 in 6-8 hour period causes respiratory

and cardiovascular morbidity – levels that have been found in Tendring Council’s area.

4.1.7. Despite the significant air quality impacts, no health impact assessment has been undertaken.

This would be considered routine in many countries and is recommended by many UK

authorities. The Colchester Borough Council 2018 Annual Air Quality Statement Report18

refers to work on “… on a methodology to carry out an Air Quality Health Impact Assessment.

This report will include an assessment of PM2.5 in Colchester and its impact on Public

Health.”(p15). This should include an assessment of the impact of the East of Colchester

development and other potential developments in the Borough. Ideally any public health

assessment should also include assessments of NO2 and O3. The latter is particularly

important given the growing evidence of the significant short-term exposure impact on

respiratory and cardiovascular health. Clearly this needs to be widened to include all the

development areas.

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4.2. NICE guidelines 4.2.1. The National Institute for Health and Care Excellence recently released guidelines for outdoor

air quality with respect to health (NG70),3 the guidance is specifically targeted towards local

authorities as the following bullet points, quoted verbatim under the “Who is it for?” section

of the document:

Local authority staff working in: planning, local air quality management and public

health, including environmental health

Staff working in transport and highways authorities

4.2.2. Broadly the guidelines recommend (Section 1.1.1) to:

“… include air pollution in ‘plan making’ by all tiers of local government, in line

with the Department for Communities and Local Government’s National Planning

Policy Framework”

4.2.3. In Section 1.1.2 the guidelines explicitly mention that when ‘plan making’, all levels of

government should consider:

“… minimising the exposure of vulnerable groups to air pollution by not siting buildings (such

as schools, nurseries and care homes) in areas where pollution levels will be high”

4.3. Health and social care costs

4.3.1. There are significant social care costs associated with the negative impacts of NO2, ozone and

PM.16 The sustainability assessment and approach to option appraisal for the garden

communities did not include consideration of health and social care impacts in terms of the

need for additional health and social care provision. Annual costs for Essex County Council

and local NHS health care organisations will be significant for even small increases in levels of

pollution. Garden cities are based on a principle that they can reduce health and social care

costs by promoting healthy places and healthy lifestyles and this is a specific goal of the NEGC

Garden Communities Charter.9 However, any increase in pollution levels will lead to

additional health and social care cost.16

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4.3.2. The recent analysis by Public Health England suggests that for areas of low pollution similar to

the current situation across Tendring and Braintree, costs for populations of 100,000 people

are measured in £100,000s per annum. Reductions in levels of pollution could lead to

significant savings with a 1μg/m3 reduction in NO2 concentration compared to the no change

scenario providing total NHS and social care cost avoided as much as £0.78million over 20

years (baseline 2015), with the largest contributor coming from social care costs (£0.38million

avoided by 2035). A similar reduction of 1μg/m3 reduction in PM2.5 concentration compared

to the no change scenario would lead to costs avoided in the region of £1.92million. This

includes £0.26 million in primary care, £0.9million in secondary care, £0.46 million in

medication, and £0.3million avoided in social care costs.16

5. Air quality in North Essex

5.1. Air quality measurement is undertaken by local authorities as a requirement of Section 82 of

the Environment Act 1995 which provides that every local authority shall review the air quality

within its area, both at the present time and the likely future air quality. Monitoring is

undertaken through the use of automatic air quality monitoring stations as well as

supplementary monitoring using diffusion tubes. DEFRA carries out an annual national

assessment of air quality using modelling and monitoring to determine compliance with EU

Limit Values. Section 83 of the Environment Act 1995 requires local authorities to designate an

Air Quality Management Area (AQMA) where air quality objectives are not being achieved, or

are not likely to be achieved, as set out in the Air Quality (England) Regulations 2000. Once the

area has been designated, Section 84 requires the local authority to develop an Air Quality

Action Plan (AQAP) detailing remedial measures to tackle the problem within the AQMA or

where national objectives (See figure 1) are not met, or at risk of not being met. AQAPs should

identify measures that will be introduced in pursuit of reducing pollutant levels to within UK

national limits.

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5.2. Existing AQMAs 5.2.1. There are three active AQMAs relevant to the proposed garden communities. These are

shown in Figure 2 in a closer zoom, and in Figure 3 relative to the proposed garden

community build areas.

Figure 2 - Colchester Borough Council active AQMAs

Figure 3 - Colchester Borough Council AQMAs in relative location to the three garden city communities.

5.2. NEA Air Quality Appraisal 5.2.1. No formal evidence based air quality appraisal has been carried out by NEA. A superficial

desk study has been prepared by Land Use Consultants Ltd (company number 02549296) on

behalf of the NEA and has resulted in a number of outputs which make up a Strategic

Environmental Assessment.20

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5.2.2. Air quality is referred to via the objective “SA13: To Improve Air Quality” and is appraised

under various spatial strategies. The results of this appraisal are shown in the table below.

Impact Reference

“mixed with negligible and uncertain minor negative

implications (0/-?).”

Results of Stage 1 SA of alternative

strategic sites [3]

“minor negative yet uncertain (-?) effects. The

uncertainty arises as it is not known exactly how and

where people will travel. “

Detailed results of Stage 2 SA of

alternative spatial strategies [4]

5.2.3. 2011 census data was used to identify commuting destinations and is the primary basis by

which impacts on local NO2 AQMAs has been judged. It is admitted that there may be an

increase of traffic through the Lucy Lane North AQMA [5] on the A12 and on the three

Colchester Borough Council centre corridors and related AQMAs [6] but this impact is

dismissed as being minor and uncertain. However, the recent Highways England report on the

A12 identifies the capacity gap of some 3000 seats on the main rail line by 2031. This will act

to push travellers onto the road with current assessments submitted in evidence supporting

the plan indicating that the current road network is already over capacity at present (see

Lawrence Walker Ltd transport critique 2019).8

5.2.4. NEAhas failed to account even for the contemporary evidence available in the form of

publicly available Defra background mapping data, as well as its own diffusion tube

measurement sets. This is negligent, given the public health impact of air pollution.

5.3. CHSS Air Quality Appraisal

5.3.1. Summary

The three garden city locations are situated in areas that have 2019 background PM2.5 in

exceedance and within 10% of the 10μg/m3 guideline for health established by the World

Health Organisation (www.who.int/airpollution/publications/aqg2005/en/)

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Colchester is set to increase in population by approximately 9% by the construction of the

East Colchester Garden Community , and currently has 13 local authority measurement

points for NO2 in the town centre that exceeded the national limit of 40 μg/m3 in 2018. The

increase in population is likely to have a significant traffic generated impact on air pollution

to existing Colchester AQMAs.

The West Colchester Garden Community proposes 24,000 new homes which will feed into

Marks Tey and the congested Lucy Lane AQMA. The junction at Marks Tey is likely to see an

increase in NO2 to above national limit values and the Lucy Lane AQMA values are likely to

grow. The A12 has measurement points exceeding the national limit and this is likely to

grow due to the traffic contribution from the build.

The West Braintree Garden Community is likely to will generate significant traffic into

Braintree and may result in existing DT measurement points to exceed national limits in

future years.

5.3.2. West Braintree Garden Community

Local Authority Monitoring

The area to the east of Braintree falls under the jurisdiction of Braintree District Council. The latest ASR for

Braintree District Council is 2018,21 but results are always lagged by one year so the latest data is for 2017.

The area to the west of Braintree falls under the jurisdiction of Uttlesford District Council but there are not

any relevant local measurements.

Figure 4 shows the Braintree District Council 2017 diffusion tube measurements in the context of the West

Braintree Garden Community development proposal.

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Figure 4 - Braintree District Council 2017 diffusion tube measurements relative to the

garden community proposal. Values shown are in μg/m3

DEFRA background maps

Figure 5, Figure 6, and Figure 7 show the 2019 DEFRA background mapped pollutant values in 1x1

km squares for NO2, PM10, and PM2.5, respectively.

Figure 5 - NO2 Defra background map for 2019 in relation to West Braintree Garden. Values shown are in μg/m3.

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Figure 6 - PM10 Defra background map for 2019 in relation to West Braintree Garden Community area proposal. Values shown are in μg/m3.

Figure 7 - PM2.5 Defra background map for 2019 in relation to West Braintree Garden Community area proposal. Values shown are in μg/m3.

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5.3.3. West Colchester Garden Community

Local Authority Monitoring

The area to the west of Colchester falls under the jurisdiction of Braintree District Council. The

latest ASR for Braintree District Council is 2018,21 but results are always lagged by one year so the

latest data is for 2017. Figure 8 shows Braintree District Council’s NO2 measurements from 2017

along with Colchester Borough Council’s NO2 measurements for 2018 against the proposed location

of the West Colchester Garden Community.

Figure 8 - Local authority NO2 measurements for 2017 and 2018 in relation to the West Colchester proposed Garden Community and the Lucy Lane AQMA. Values are in μg/m3.

It is proposed that 24,000 homes be built in the West Colchester Garden Community. This is likely

to have a significant impact on the pollution at along the A12 to Marks Tey, at the junction at Marks

Tey, as well as the Lucy Lane AQMA as the figure above should illustrate.

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DEFRA Background Maps

Figure 9, Figure 10, and Figure 11 show the 2019 DEFRA background mapped pollutant values in

1x1 km squares for NO2, PM10, and PM2.5, respectively.

Figure 9 - NO2 Defra background map for 2019 in relation to West Colchester Garden Community area proposal and Lucy Lane AQMA. Values shown are in μg/m3

Figure 10 - PM10 Defra background map for 2019 in relation to West Colchester Garden Community area proposal and Lucy Lane AQMA. Values shown are in μg/m3.

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Figure 11 - PM2.5 Defra background map for 2019 in relation to West Colchester Garden Community area proposal and Lucy Lane AQMA. Values shown are in μg/m3.

5.3.4. East Colchester Garden Community

Local authority monitoring

Local authorities in the UK are required to monitor airborne pollutants wherever an AQMA has

been established, or where there is a risk that an AQMA may be needed. Monitored values are

published in an Annual Status Report (ASR). The latest ASR for Colchester Borough Council is

2019,22 but results are always lagged by one year so the latest data is for 2018.

Figure 12 shows the bias corrected and annualised NO2 diffusion tube results (and one automatic

analyser result) for 2018 from Colchester Borough Council in relation to the proposed East

Colchester Garden Community.

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Figure 12 - Bias corrected and annualised NO2 diffusion tube results (and one automatic analyser result) for 2018 from Colchester Borough Council. Values shown are in μg/m3.

DEFRA Background Maps

Figure 13, Figure 14, and Figure 15 show the 2019 DEFRA background mapped pollutant values in

1x1 km squares for NO2, PM10, and PM2.5, respectively.

Figure 13 - NO2 Defra background map for 2019 in relation to East Colchester Garden Community area proposal and Central 1 and 2 AQMAs. Values shown are in μg/m3.

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Figure 14 - PM10 Defra background map for 2019 in relation to East Colchester Garden Community area proposal and Central 1 and 2 AQMAs. Values shown are in μg/m3.

Figure 15 - PM2.5 Defra background map for 2019 in relation to East Colchester Garden Community area proposal and Central 1 and 2 AQMAs. Values shown are in μg/m3.

Colchester Borough Council does not monitor PM2.5 in the city however a baseline emissions

modelling study identified that the average across the urban area was between 16-18μg/m3 and

that Colchester does not breach the National Air Quality Objectives for PM2.5, but is well above

WHO limits of 10 μg/m3. These levels would be consistent given the background levels modelled by

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DEFRA. In fact, across the whole area PM2.5 levels are close to, or exceed, WHO limits. If

development is to be consistent with current proposals in the Clean Air Strategy4 then more

attention needs to be paid to assessing development impact in these areas. Undoubtedly larger

developments are likely to create higher levels of emissions without significant mitigation strategies

to create zero emission dwellings, restrict care use etc. Obtaining some relevant air quality

monitoring data is needed to determine with any accuracy the future predicted pollution levels.

This is particularly important at the A12/A120 interchange and associated approach roads to the

roundabouts. Traffic monitoring suggests that there is already significant congestion at the

interchange which could have an impact on pollution levels.

6. Estimating air quality impact of the proposed garden communities

6.1. Given that the NPPF requires air quality to be considered at a plan making stage it is perhaps

unusual that none of the development documents address air quality impacts. It would be

possible to make some assessment of the potential increase in emissions due to development

and then demonstrate how these are to be mitigated. While plans are put forward for

“sustainable development” and alternatives to car travel there is no assessment of air quality,

potential costs and whether proposed mitigation will be feasible and effective, as required by

the ruling in Gladman vs Secretary of State ([2019] EWCA Civ 1543).

6.2. The Sustainability Appraisal20 makes only limited reference to air quality impact. Section 3

includes reference to achieving Objective 13 – to Improve Air Quality (P162):

3.127 None of the strategic sites would be located within an AQMA.

3.128 It is difficult to predict with any certainty which strategic sites would be most likely to

generate traffic that would exacerbate air quality issues within existing AQMAs, either

within North Essex or in other nearby local authority areas. Therefore, without traffic

modelling of each strategic site alternative, this assessment needs to be treated with a great

deal of caution. In our view, based on existing commuting patterns for the locations where

the sites would be developed, those most likely to generate traffic that travels through

AQMAs would be:

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• ALTGC2 Land East of Silver End.

• ALTGC4 Land at Marks Tey Option One.

• ALTGC6 Land at Marks Tey Option Three.

• ALTGC7 Land at East of Colchester Option One.

• ALTGC8 Land at East of Colchester Option Two.

• ALTGC9 Land at East of Colchester Option Three.

• ALTGC10 Land at East of Colchester Option Four.

• ALTGC11 Langham Garden Village.

• NEAGC2 Colchester Braintree Borders Garden Community.

• NEAGC3 Tendring Colchester Borders Garden Community.

• SU4 Land South of Haverhill.

• VE5 Tendring Central Garden Village.

Sustainability Assessment Figure 3.20: Proximity to sources of air pollution (p144) 6.3. The SA appears to suggesting, incorrectly from our analysis, that as there will not be any impact

on AQMAs or at least such impact would be minimal:

26

3.129 All of these sites scored uncertain minor negative (-?) effects at all dwelling capacities.

In practice, all of the strategic sites are likely to generate traffic and the larger their scale,

and the closer they are to the AQMAs and/or the main road commuting corridors, the more

likely they are to result in traffic travelling through AQMAs.

6.4. As discussed in the previous section, this assumption has not been based on any analysis of

current air quality or potential impact of construction and traffic generation. While accepting

that more detailed traffic modelling is required, it is clear that there would be impacts on

AQMA’s from some sites. To identify preferred sites without undertaking more detailed work is

not in line with best planning practice. Nor has there been any comparative assessment to

compare different locations for development and with different approaches – for example

urban expansion or proportionate growth of existing communities which create different

concentrations of population and different traffic and travel patterns.

6.5. The traffic implications will be significant and while improvements in traffic emissions are

predicted in the future it is unlikely that significant reductions in total traffic emissions due to

improved emissions and increased use of hybrid and electric vehicles is unlikely for at least a

decade given that the majority of the vehicle fleet will remain fuelled by diesel and petrol. In

order to estimate total emissions of NO2 and PM an estimate of trips generated needs to be

undertaken. Any air quality assessment for developments is linked to how many vehicle trips

are generated. Based on a medium urban vehicle trip generation rate of 5 vehicle journeys

per day per dwelling (TRIC) in the period to 2028 it is expected to build 2250 dwellings over two

sites with an additional 4250 dwellings across three sites between 2028 and 2033. In the first

five years with an estimated 10km journeys this could generate as much as 17,000 additional

kg of NOx and over 4,000kg of PM10.

6.6. With the current proposals focusing on large scale developments along a narrow road

transport corridor there would be a significant increase in traffic levels above that already

predicted by the Department for Transport. Even with the proposed mitigation measures

significant numbers of trips will be generated into and from the development sites related to

27

commuting for work and vising larger urban areas such as Colchester or Chelmsford along the

A120 and A12. Unless dedicated rapid transit routes are established increased congestion. It is

notable that the town centre in Colchester shows 13 points exceeding the national annual limit

of 40 μg/m3, or approximately 1/5th of measured locations. The nearby Lucy Lane AQMA has a

value of 60 μg/m3, which is 50% higher than the national annual limit. It isn’t rational to claim

that a settlement of, 7500 homes and 17,000 people, an increase of almost 9% of Colchester’s

population, is going to have a negligible impact on existing AQMA receptors. Any development

at West Tay will also impact on Colchester AQMAs.

6.7. In their planning statements there is a focus on a Rapid Transit System although, as identified

by Lawrence Walker Limited,8 there is little detail of what this is. More importantly the

downgrading to a bus system appears to have significant weaknesses in terms of being able to

operate when it is predicted that the main arterial routes (A12 and A120 will be operating

above full capacity. This suggests that it would not be possible to develop dedicated bus lanes

needed for bus-based rapid transport systems. This clearly limits their potential. In fact, in the

submitted plan document TN1 paragraph 3.31 states that only 6% of trips are predicted to be

made by bus at the end of the Plan Period. This only rises to 13% by completion in 2078

according to Figure 7-2 of EB/080. From Lawrence Walker Limited in their submission correctly

conclude that “… in reality CBBGC is a long-term car-based small city served by roads that are

wholly inadequate to meet its needs.” (LWL Para 2.13). This has significant implications for air

quality as the mitigation for air quality impact is based on significant modal shift. However,

from the available documents there is a lack of detail and Lawrence Walker Limited point to

significant weaknesses in forecasting traffic levels, modal shift and lack of detail for

infrastructure improvements.

6.8. Air quality will be also be affected significantly during the construction stage, in addition to the

total emissions from completed and occupied residential and commercial developments and

from traffic generated from within the developments and traffic associated with coming into

the development areas. Total emissions will also need to include boiler emissions at current

standards – certainly for the immediate five years. The long construction period means that

28

there will be emissions arising from construction and completed developments occurring

concurrently and any assessments need to consider the cumulative impact.

6.9. Dispersion modelling should also be incorporated. For ultrafine particle counts, the gradient is

100–300m; NO2 has gradients of 200–500m. In particular, PM2.5 has a longer gradient fall off

than NO2 suggesting ultrafine particles remain a greater risk near roads. However, wind

direction is important. On the upwind side, concentrations drop off to near background levels

within 200m and, in the case of particles, probably within 100m or less. On the downwind side,

concentrations do not generally reach background levels until 300–500m. In some studies, this

was extended to up to 1500m for NO2 and 800m for ultrafine particle number counts (WHO

2013). Such an analysis can be laid over the DEFRA Background maps.

6.10. It is not clear from the current proposals whether it will be possible within the initial 10 year

time frame to achieve substantial reductions in emissions through modal shift or through

improved vehicle technology. Undertaking a full air impact analysis will be required to

ascertain whether emissions will exceed current national limits for NO2 by 2033. However, it is

highly likely that annual limits will be lowered in the future leading to potential air quality

exceedances. However, there is currently clear evidence to demonstrate that any increase –

even 1 or 2µg/m3 in PM2.5 – is likely to exceed the prosed limits for PM2.5 set out in the

Government’s 2019 Clean Air Strategy. By 2033 there will be 5,910 dwellings generating

potentially over 11,000,000 additional vehicle journeys per annum (based on a TRIC rate of 5

per dwelling per day) in the North Essex area which will be additional to wider traffic growth.

Central to achieving high modal shift is travel time. The evidence shows that higher shifts occur

when travel time is substantially reduced for public transport, there is high capacity and

regular, frequent services. Transit services need to be fully integrated to allow easy choice of

destination. Current evidence supports the benefit of light rail transit systems as producing

total lower emissions than bus transit systems.23

6.11. The assessment should not rely on any significant immediate reductions in vehicle

emissions. Reductions arising from improved vehicle emissions can only be factored in post

2030 as it will be about a decade before changes in vehicle technology are likely to have a

significant impact on roadside emissions. The assessment should also be based on better data

29

collected through additional monitoring across the proposed locations with an emphasis on

recording actual key road network pollution levels.

7. Conclusion 7.1. The development of over 40,000 houses and associated infrastructure will have a negative air

quality impact. The developments are being placed in an area that already experiences levels of

PM2.5 above WHO limits and, In Colchester includes current AQMAs and higher levels of PM2.5

than the surrounding area. The lack of any air quality assessment on pollutant levels and on

human health means that the current plans do not conform with the NPPF. In addition, the

plan does not meet current environmental planning guidance, nor follow NICE guidance. The

current desktop assessment of air quality lacks any reference to existing data or evidence. As

such the current assessment is completely inadequate and the plan should fail on this basis

alone.

7.2. Despite improvements in vehicle emissions and the gradual shift towards hybrid and electric

vehicles, it is likely that vehicle emissions will remain the major contributor of NO2 and PM for

the next decade or more given the lifetime of current vehicles of between 10 and 15 years.

Without incentives to move away from diesel vehicles or purchase electric vehicles – and

provide a sufficiently extensive recharging network, petrol and diesel vehicles will continue to

dominate the vehicle fleet. Mitigation that simply relies on improving emissions standards will

not sufficiently provide substantial reductions in NO2 and PM in the short to medium-term

(Department for Transport 2018). Other mitigation to encourage modal shift from cars to

public transport, walking and cycling, also requires substantial investment and is a long-term

strategy. Much of the supporting data for modal shift arising from the proposed developments

is missing or not clear, and in places contradictory.

7.3. The proposed development plan fails to meet the requirements of the NPPF paragraphs 103,

117, 122, 127, 180, 181 and 202 nor is it consistent with current Environmental Impact

Assessment (EIA) planning and NICE guidance. The plan is unsound and should not be

approved as it stands.

30

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