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Related to: Ecosystem Services, Ill Health and DisabilityLife ExpectancyActive Travel

Key Facts:

  • 40,000 deaths in the UK are attributable to outdoor air pollution, with more linked to indoor pollutants.
  • Air pollution can cause, or contribute to, low birth weight, pre-term births, cancer, asthma, chronic bronchitis, stroke and heart and circulatory disease, diabetes, obesity, and changes linked to dementia.
  • Air pollution is harmful to everyone. However, there are factors that make some people more vulnerable:developing foetus, age, existing medical conditions, obesity, and living, learning or working near busy roads.
  • Levels of carbon monoxide, benzene, sulphur dioxide and particular matter in Bath and North East Somerset have not exceeded government air quality objectives.
  • Results from automatic monitoring of nitrogen dioxide in 2012 show that all sites except at Saltford exceeded the annual average objective (two diffusion tube monitoring locations on the A4 in Saltford did exceed the annual average objective).
  • Road traffic in B&NES contributes up to 92% of the total nitrogen dioxide (NOx) concentration.
  • There are 16 existing or proposed measures to improve air quality in B&NES.

The monitoring of air quality commenced in the Bath and North East Somerset area during the 1960s with programs to measure smoke and sulphur dioxide from domestic chimneys and other sources. The monitoring of local air pollution is being continually developed to fulfill higher National and European air quality standards resulting from growing evidence and concern regarding the negative health effects and environmental damage caused by air pollutants.

Since 1997 the national government has required all local authorities through a Local Air Quality Management (LAQM) process to review and assess airquality in their area with reference to the pollutants specified in the National Air Quality Strategy. Moreover, in 2000 air quality objectives for local authorities were set by government. Where levels of pollutants are likely to exceed nationally set objectives local authorities are required to establish an Air Quality Management Area (AQMA) coupled with an Air Quality Action Plan (AQAP) setting out the measures they intend to put in place in order to try and reduce pollutant levels to achieve the air quality standards set by the government. During 2011 air pollutionmonitoring was carried out at ten automatic monitoring sites inBath and North East Somerset. Pollutants monitored include nitrogen dioxide (NO2), carbon monoxide (CO), benzene and particle matter (PM 10) as required by government regulations. In addition the Council also monitor ozone (O3), pollen and black carbon. 1

What does the data say?

Unicef’s 2013 air pollution rates in rich countries comparative overview 2

In Unicef’s 2013 air pollution rates in rich countries comparative overview, Unicef compares 29 of the world’s most advanced economies.

According to Unicef’s report, in the UK, the average annual concentration of fine particulate matter in the atmosphere (annual PM10 [μg/m3]) is approximately 23 parts per million. The UK has the 10th lowest concentration of fine particulate matter in the table.

The lowest levels of air pollution are found in Estonia, Finland, Ireland, Luxembourg and the United States (all below 20 parts per million).The good result for the United States is influenced by legislation on air pollution (1997, revised in 2006) which enforced stricter limits than in most European countries. The highest levels are found in Greece, Italy, Latvia, Poland and Romania (all higher than 30 parts per million).

It is important to note that one of the limitations of these league tables is that internationally comparable data on children’s lives is not sufficiently timely. Between the collection of data in a wide variety of different settings and their publication in quality-controlled, internationally comparable form, the time-lag is typically two to three years. This means that most of the statistics on child well-being used in this report, though based on the latest available data, apply to the period 2009–2010.

Levels of pollutants in Bath and North East Somerset 3

Monitoring data carried out in 2009-2012 in Bath and North East Somerset at automatic monitoring sites and a number of non-automatic monitoring sites show that levels of carbon monoxide, benzene, sulphur dioxide and particular matter have not exceeded government air quality objectives and so do not currently present a problem.4

Nitrogen dioxide 5

One of the chief pollutants from vehicle emissions is nitric oxide, which through oxidation creates nitrogen dioxide (NO2). It plays a major role in atmospheric reactions that produce ground-level ozone or ‘smog’. This is the main pollutant by which air quality is assessed. 6

In 2009 the highest concentration of NO2 was recorded at Lambridge (just east of the junction with the old Gloucester Road) with an annual mean of in excess of 80μg/m3. 7

Results from automatic monitoring of nitrogen dioxide in 2012 show that all sites except at Saltford exceeded the annual average objective (two diffusion tube monitoring locations on the A4 in Saltford did exceed the annual average objective). All these sites are within Air Quality Management Areas. 8

The London Road, Guildhall and Windsor Bridge sites exceeded the hourly objective for NO2, but they were less than the 18 times allowed by the objective in 2012. 9


The trend data shows that 2012 was not a peak year for NO2, with monitoring results being similar to previous years, 2 sites were lower than 2011 and 3 sites higher. 10

Carbon monoxide 11

The levels of carbon monoxide (CO) for Bath and North East Somerset in 2012 were below the limits set.

Levels of carbon monoxide have generally decreased over time.


There were no exceedences of the benzene objectives during 2012, and trends in benzene show that levels dropped in 2012 compared to previous years. 13

Particle matter 14

Particle matter is specks of solid material suspended and transported in the air. There is a wide range of particles in the air - from relatively large - those that form visible dust, reducing visibility and soiling buildings, to the very fine particles that can penetrate deep into our lungs.

Monitoring for particle matter (PM10) was been carried out at 2 sites during 2012. The results show that the annual average objective was not exceeded during 2012 and the number of exceedences of the 24 hour objective was below 35 at both sites.  Levels of particle matter were similar to previous years. 15

Ozone 16

Ozone (O3) is a naturally occurring gas generated in the higher levels of the earth’s atmosphere, the stratosphere, by the action of ultra violet light from the sun on oxygen molecules.

In the stratosphere ozone has a beneficial effect on health in that it helps to filter out harmful ultra violet rays that can cause skin cancer. In the lower atmosphere, the troposphere, where we live, ozone has an irritant effect on the delicate surface tissues of the body, such as eyes, nose and lungs at concentrations experienced on warm sunny days in the UK. Unfortunately, the ozone levels in the stratosphere, where the effects are beneficial, are reducing and the levels in the troposphere, where the effects are harmful, are increasing.

The transboundary nature of this pollutant is recognised in the Government Air Quality Strategy and therefore, the objective has not included in Local Air Quality Management.

The ozone guide (100 g/m3, as an 8-hour mean) was exceeded 5 times in 2012, which was below the objective which allows for 10 exceedences. 17

Ozone levels have not varied significantly over time.

Pollen 18

Pollen is a naturally occurring pollutant that is a powdery substance produced by the anthers of seed-bearing plants. It causes hay fever, and unlike other pollutants, the amount of pollen in the air cannot be regulated or prevented. There is, however, great advantage for sufferers to be aware of the daily pollen count and forecast to enable them to gauge the effectiveness of their drugs and to plan ahead to minimise exposure to expected high levels of pollen.

Bath and North East Somerset Council has monitored grass pollen since 1991 as part of a network now co-ordinated by The Meteorological Office.

Most hay fever sufferers experience symptoms when the pollen count rises above 50 grains per cubic metre.

The trend for 2012 in Bath and North East Somerset differs from previous years, with pollen counts being lower throughout most of the summer with only the occasion peak. 19

There were 0 days when the count was greater than 100 grains per cubic metre which compares with a mean of 5 days in the previous ten years and 4 days where the count was greater than 50 grains compared with a mean of 29 in the previous ten years. The levels are lower than in previous years, this is due to wet weather conditions during summer of 2012. 20

Black carbon 21

Black carbonis material produced by the incomplete combustion of fossil fuels, biofuels and biomass. As well as having damaging health implications, black carbon has also recently remerged as a major contributor to climate change, possibly second only to CO2. 22

The level of black carbon had been decreasing over time, but there was a slight rise in the levels in 2011.

Black Carbon monitoring ceased in Bath & North East Somerset in 2012. 23

Sulphur dioxide 24

Sulphur dioxide (SO2) monitoring in Bath and North East Somerset ceased in 2007. Previous monitoring that was carried out (1999-2007) indicated that the levels of SO2 did not exceed the objectives set by the government.

Air Quality Management Areas 25


Figure 1 : Air Quality Management Area in Keynsham Town Centre 26

The proposed changes to the Bath Air Quality Mangement Area have now been adopted. You can find a map of the proposed changes on p62 of the 2012 Air Quality Updating and Screening Assessment for Bath and North Somerset Council. 27  28

Also, on 9th May 2013 the Council made Bath Road, Saltford an Air Quality Management Area, and this came into operation on 4th July 2013. The area extends along the Bath Road from its junction with Beech Road until 150 metres south of the Glen and encompasses all the buildings whose facades are within the area. 29

Sources of pollutants 30

Road traffic contributes up to 92% of the total nitrogen dioxide (NOx) concentration, with heavy duty vehicles (HDV’s) contributing 24 - 57.1%

The air pollution dispersion model testing predicts that a Low Emission Zone covering Air Quality Management Areas, requiring cleaner HGV engine standards would have the effect of lowering oxides of nitrogen emissions by 17% to 78.43µg/m3 (microgrammes per cubic metre) compared to the 2016 ‘do nothing’ scenario of 94.54µg/m3 (assuming 50% of HGVs meet at least EURO V standard and 50% EURO VI). The model predicts that the measure will reduce NO2 emissions by an average of approximately 7% in the Air Quality Management Area. 31

Impacts of poor air quality

2016 report produced by the Royal Colleges of Physicians and of Paediatrics and Child Health 32 

A national report produced by the Royal Colleges of Physicians and of Paediatrics and Child Health in February 2016 outlines the current understanding about the effects of air pollution on health and recommendations on how to reduce air pollution and its impacts. 

Its key findings reiterate those of previous reports by the Department for Rural Affairs (Defra) and the World Health Organisation (WHO):

Air pollution can cause, or contribute to, low birth weight, pre-term births, cancer, asthma, stroke and heart disease, diabetes, obesity, and changes linked to dementia. 

Damage occurs across a lifetime, and is either the result of high-level acute exposure or prolonged low-level exposure.

Air pollution is harmful to everyone. However, there are factors that make some people more vulnerable:

These vulnerabilities can also be heightened in lower income communities. 

In the UK the costs of health problems resulting from air pollution to society, business, health services, and people who suffer from illness and premature death, add up to more than £20bn a year.

There is also a briefing note linked to this report. 

International evidence on the effects of air pollution on health 33

There is a large body of international evidence on the effects of outdoor air pollution on health. According to the World Health Organisation thousands of new scientific papers have been published on this topic in the last few years. They include the following, with the WHO 2013 review of the evidence on health aspects of air pollution being one of the most recent:

  • COMEAP (Committee on the Medical Effects of Air Pollution), 2010: The Mortality Effects of Long-Term Exposure to Particulate Air Pollution in the United Kingdom.
  • COMEAP, 2009: Long-term exposure to air pollution: effect on mortality (final report - June 2009).
  • COMEAP, 2006: Cardiovascular disease and air pollution.
  • Environmental Audit Committee, 2010: Report on air quality.
  • WHO, 2013: Review of evidence on health aspects of air pollution – REVIHAAP Project Technical Report.
  • WHO, 2005: Effects of Air Pollution on Children’s Health.
  • WHO, 2004: Health Aspects of Air Pollution.

Short and long-term exposure impacts 34

Short-term impacts are thought to include effects on the respiratory system, increased medication use and an increase in hospital admissions.

Long-term exposure, continued or frequent exposure to higher concentrations than those normally found in the ambient air may cause increased incidence of acute respiratory illness. Children (see Child Health Asthma rates), the elderly and those already suffering from respiratory illnesses are more vulnerable. 35The evidence suggests that long-term exposure can lead to permanent reductions in lung development and function, and a subsequent reduction in life expectancy.

Both short term and long term exposure to air pollution have been linked to conditions such as asthma exacerbation, chronic bronchitis, heart and circulatory disease, and cancer.  36

Premature deaths 37

The evidence indicates that exposure to poor air quality can reduce life expectancy. In 1998 the Committee on the Medical Effects of Air Pollutants (COMEAP) estimated that on average up to 24,000 people in the UK die prematurely every year as a result of short-term exposure to air pollution and thousands more are hospitalised. If new evidence was taken into account it is possible that this figure could now be as much as 35,000 per year. 38

Potential effects of exposure to different air pollutants 39

Table 1: The potential short and long term effects of exposure to air pollutants 40  41  42


Possible effects related to short term exposure


Possible effects related to long term exposure


Particulate matter (PM10) and (PM2.5)


   Lung inflammatory reactions

   Respiratory symptoms

   Adverse effects on the cardiovascular system

   Increase in medication usage

   Increase in hospital admissions

   Increase in mortality

   Increase in lower respiratory symptoms

   Reduction in lung function in children and adults

   Increase in chronic obstructive pulmonary disease

   Reduction in life expectancy, due to cardiopulmonary mortality and probably lung cancer


   Cardiovascular mortality and morbidity.

   Atherosclerosis, adverse birth outcomes and childhood respiratory disease

   Damage to neurodevelopment and cognitive function




   Adverse effects on pulmonary function

   Lung inflammatory reactions

   Adverse effects on respiratory symptoms

   Increase in medication usage

   Increase in hospital admissions

   Increase in mortality

   Damage to cognitive development and reproductive health, including preterm birth


   Reduction in lung function development


Nitrogen Dioxide


   Effects on pulmonary function, particularly in asthmatics

   Increase in airway allergic inflammatory reactions

   Increase in mortality

   Reduction in lung function

   Increased probability of respiratory symptoms




   Hay fever

   Pollen asthma

   Hay fever

   Pollen asthma

Particle Matter (PM) - is thought to have the most damaging impact on health with adverse effects to health seen at very low concentrations. The fine particles can be small enough to be inhaled deep into the lungs, and so are believed to contribute to diseases associated with both the lungs and heart. Studies have shown a 15% decrease in the risk of heart disease deaths with every particulate matter decrease of 10ug/m3 (micrograms per cubic metre). 43

The 2007 UK Government Air Quality Strategy (AQS) estimated that (based on air quality data from 2005) manmade PM alone reduces the average life expectancy of people living in the UK by 7-8 months (PEAC, 2010). An updated assessment based on 2008 data, indicated that improvements in pollutant levels since 2005 mean that the average reduction in life expectancy of UK residents as a result of long term exposure to PM2.5 is now 6 months. 44

It is also estimated that in 2008 29,000 premature deaths in the UK were attributed to long term exposure to PM2.5. This is higher than the 2,222 people killed in road traffic collisions in 2009 (DFT), and 15,479 deaths partially or wholly attributable to alcohol in England in 2010 (North West Public Health Observatory). However, these figures do not take into account the average number of years lost in life, which will be much higher for road traffic collisions compared with premature mortality from air pollution.

Nitrogen dioxide (NO2) - can irritate the lungs, increasing the symptoms of those suffering from lung diseases and lowering resistance to respiratory infections such as influenza (see Respiratory Infections).

At relatively high concentrations, NO2 causes inflammation of the airways. There is evidence to show that long-term exposure to NO2 may affect lung function and enhances the response to allergens in sensitised individuals (see Asthma). Thus, people who suffer from asthma may find that high levels of air pollution causes them to use their inhalers more often or it may even cause an attack.  45

Pollen - affects 10% of the UK population in the form of hay fever. The most common culprit is grass pollen. Sufferers experience constantly itching and streaming eyes and noses, and in 30% of cases, pollen asthma. Hay fever causes difficulties for sufferers in their domestic, social and working life. More working days are lost nationally due to hay fever than from industrial injuries. 46

Vulnerable groups 47

The impact of poor air quality on health is unequal with greater effects on unborn and very young children, older people, those with pre-existing heart and lung disease, smokers, the most economically deprived, and those exposed to relatively high levels of pollution due to where they live.

Children (and unborn foetuses)

Children (and unborn foetuses) are thought to be particularly vulnerable to the effects of air pollution. This is because their lungs, metabolic and immune systems are still developing. There is a growing body of evidence shows that prenatal exposure to air pollution is associated with a number of adverse outcomes during pregnancy. These include low birth weight, pre-term births, birth defects, and an increased risk of chronic diseases in later life. Emerging evidence also suggests that long-term exposure to particulate matter, at levels such as those seen in major cities, can alter emotional responses and impair cognition. There is also evidence to suggest that poor air quality can increase cough and bronchitis, exacerbate asthma, impair lung function, and increase cardiovascular and respiratory related deaths in babies and young children. 48

A significant body of evidence supports the explanation that much of the morbidity and mortality related to air pollution in children occurs via interactions with respiratory infections, which are frequent among children. Evidence suggests a causal relationship between exposure to ambient air pollution and increased incidence of upper and lower respiratory symptoms (many of which are likely to be symptoms of infections).

Smokers 49

It is believed that smoking can also increase your vulnerability to the short-term effects of air pollution and will have a much greater effect on your health overall. Diseases of the lungs and heart that are attributed to smoking can also be affected by poor air quality.

Economic costs of poor air quality 50

It is thought that as well as contributing to increased morbidity and premature mortality, poor air quality also contributes to higher hospital admissions, emergency visits, medication use, and associated service costs. The most conservative estimates suggest that ill health related to particulate matter only, costs the NHS £9 billion a year, though it could be as much as £17 billion. 51 The £9 million estimate is comparable to the growing annual health costs of obesity at £10 billion (although the basis of the cost calculation differs). 52 

A report by the Cabinet Office estimates that the wider cost of air pollution from transport (in urban areas) alone is between £4.5 and £10.6 million. This compares with the costs associated with excess delays (£10.9m), accidents (£8.7m), physical inactivity (£9.8m), noise (£1.2-3.7m), and greenhouse gas emissions (£3-5m) from transport. 53

Economic costs of improving air quality [fn] Courthold, N. (May 2012) 2012 Air Quality Updating and Screening Assessment for Bath and North Somerset Council, Environmental Monitoring and Licensing, Bath and North East Somerset Council,

In monetary terms, it is thought that the benefits of improving air quality are 5-20 times greater than costs for a 20% reduction in particle matter. Therefore, there is a strong economic case for even stronger reductions. The benefits of further reductions are  thought to be 1-3 times greater than costs. This is greater than public smoking and motor vehicle accidents in terms of the effects on life expectancy.

The impacts of air pollution in Bath and North East Somerset

Local research in 2014 was unable to determine the extent to which air pollution in B&NES contributes to health problems locally because it was not possible to separate it from other factors such as age, lifestyle, deprivation and air pollution exposure from elsewhere. 

Given the quantity of national and international research linking poor air quality to ill-health, there is no reason to believe that this is any different in B&NES, and so it is likely air pollution will continue to have an impact on local residents.

Are we meeting the needs? 54

Local air quality strategy aims to ensure that the Council moves towards building a healthier community and improving the quality of life and the environment through actions and initiatives to improve air quality locally. This will require the integration of air quality considerations into the various planning functions of the individual local authorities, including land-use (development planning and control), transport, economic, environmental and sustainable planning.

An Air Quality Action Plan was adopted in April 2011.

Progress that has been made with the measures identified in the Air Quality Action Plan: 55 

  • The Low Emission Zone Feasibility Study is close to completion.
  • The Department for Transport in December 2011 awarded  Bath & North East Somerset Council  £180,000 for electric vehicle infrastructure in the area. Charging points have been installed and are in operation at a number of sites.
  • The continued growth of the Freight Transhipment Scheme, with 25 retailers (29 premises) in Bath now supplied by an electric vehicle (compared with 19 this time last year). Oxides of nitrogen emissions reduction per month in April 2013 was 23.43kg compared to 12.92kg in April 2012.
  • The Bath Transport Package has provided an increase in park & ride parking spaces of 890 spaces (50% capacity increase); variable message traffic signs; pedestrian friendly city centre road layout works; and real-time information on key bus commuter routes.
  • The CIVITAS Renaissance project also included a variable message sign and automatic number plate recognition cameras at Upper Bristol Road/Windsor Bridge Road to discourage heavy goods vehicles from using the central A4 corridor where a traffic regulation order exists.
  • Also part of the CIVITAS Renaissance, all but one of the Park and Ride buses in operation are hybrid diesel-electric buses.

Reducing nitrogen dioxide levels

Nitrogen dioxide is the principal pollutant that needs to be addressed locally. Areas within Bath and North East Somerset have been identified as having nitrogen dioxide (NO2) concentrations greater than the Government’s objectives (annual average NO2 concentration greater than 40 µg/m 3).

Levels of NO2 are not decreasing at the same rate as they are nationally and so it is important that lower more realistic targets are set. It can be seen that in areas where the national air quality objectives are exceeded, there needs to be a reduction of between 4.9% and 73.3% in emissions of nitrogen oxides in order to meet the objectives across Air Quality Management Areas.

NO2 can be controlled without reducing other gases, so mitigation should not just focus on reducing nitrogen, but rather the source of this and other pollutants.

In terms of cost benefit, indications are that the most cost effective measure might be either the introduction of electric vehicle charging points; or a promotional website.

What does the community say? 56

The Consultation Draft Quality Action Plan for Bath was issued to stakeholders and published online in November 2009. This consultation process was under taken in accordance to the government’s Local Air Quality Management Policy Guidance

Consultation (PG09) which states:

‘ Local authorities must consult on their preparation of an air quality Action Plan after developing options with relevant key players….’

A wide range of stakeholders were consulted including the following:

  • Every household in the Bath Air Quality Management Area
  • Residents associations
  • Other councils in the South West
  • Highways Agency
  • Federation of small businesses

There were 128 questionnaire responses from an estimated 3,800 posted. This equates to a return of approximately 4%.

56.2% of respondents agreed or strongly agreed with the Bath Transport Package overall (Measure1).

Measure 2, the Feasibility Study for a Low Emission Zone was supported by 67.2% of the respondents.

There was a strong 82% support for the Trial of low emission buses on park and ride services (Measure 3).

Measure 4, the Urban Freight Transhipment (Consolidation Centre) demonstration received 56.3% support from respondents.

54.7% of respondents agreed or strongly agreed with the Measure 6, the bicycle hire scheme trail.

56.2 % of respondents agreed or strongly agreed that Measure 7, Electric Vehicle Charging Point Infrastructure was a good idea.

Measure 8 that aims to Improve Building Emission Assessments received 44.5% definite support from respondents, with the majority of respondents not having views on it either way.

Only 39.8% of respondents demonstrated any definite support for the ECO Stars Vehicle Recognition Scheme (Measure 9), the principal doubts people had being over the cost-benefits of the scheme, how it would be monitored, and whether it would actually achieve any quick improvements to air quality.

69.5% of respondents agreed or strongly agreed with the proposed Review of Emission Reduction and Fuel Additive Technologies (Measure 13).

Measure 14, the Rossiter Road Traffic Management Measures, received 44.5% support from respondents

What can we realistically change?

2016 report produced by the Royal Colleges of Physicians and of Paediatrics and Child Health 57 

The national report produced by the Royal Colleges of Physicians and of Paediatrics and Child Health in February 2016 made the following key recommendations about how to reduce air pollution and its impacts:

  • Educate professionals and the public - The NHS and patient charities must educate health professionals, policymakers and the public about the serious harm that air pollution causes. 
  • Promote alternatives to cars fuelled by petrol and diesel -  Government, employers and schools should encourage and facilitate the use of public transport and active travel options like walking and cycling. 
  • Put the onus on the polluters - Polluters must be required to take responsibility for harming our health. Political leaders at a local, national and EU level must introduce and enforce tougher regulations, including reliable emissions testing for cars. 
  • Monitor air pollution effectively - Air pollution monitoring by central and local government must track exposure to harmful pollutants in major urban areas and near schools. These results should be communicated proactively to the public, in a clear way that everyone can understand.
  • Act to protect the public health when air pollution levels are high - When limits are exceeded, local authorities must have the power to close or divert roads to reduce the volume of traffic, especially near schools.
  • Tackle inequality - Regulators, local government and NHS organisations must prioritise improvements in air quality in our most deprived areas, setting high standards of emission control across all sectors of industry.
  • Protect those most at risk - Children, older people, and people with chronic health problems are among the most vulnerable to air pollution. Public services must take account of this disproportionate harm through local tools such as planning policies for housing and schools, equalities impact assessments, and joint strategic needs assessments. At an individual level, healthcare professionals should help vulnerable patients protect themselves from the worst effects of air pollution.
  • Lead by example in the NHS - The health service must no longer be a major polluter; it must lead by example and set the benchmark for clean air and safe workplaces.
  • Define the economic impact of air pollution -  We need further research into the economic impact of air pollution, and the potential economic benefits of well-designed policies to tackle it.
  • Quantify the relationship between indoor air pollution and health - We must strengthen our understanding of the relationship between indoor air pollution and health, including the key risk factors and effects of poor air quality in our homes, schools and workplaces. A coordinated effort among policymaking bodies will be required to develop and apply any necessary policy changes.
  • Determine how global trends are affecting air quality - From increased energy production and consumption to global economic development and urbanisation, we need to improve our understanding of how major social and economic trends are affecting air quality and its twin threat, climate change.
  • Develop new technologies to improve air pollution monitoring - We need better, more accurate and wider-ranging monitoring programmes so that we can track population-level exposure to air pollution. We also need to develop adaptable monitoring techniques to measure emerging new pollutants, and known pollutants that occur below current concentration limits. 
  • Study the effects of air pollution on health - To appreciate fully the risk to health, we need further research on air pollution’s effects on the body.

DEFRA Local Air Quality Management Policy Guidance 

The Department of Farming and Rural Affairs also published some guidance on Local Air Quality Management in 2016. 

Low Emission Zone Feasibility Study for Bath 58

Low Emission Zone (LEZ) is a geographically defined area where the most polluting vehicles in the fleet are restricted or discouraged from using. The aim is to improve air quality by setting an emissions based standard for the vehicles within the area. Detailed information and guidance on low emission zones can be found on the Supporting Guidance page. 59

There are two low emission zones in the UK, the largest scheme is in operation in London and restricts diesel engine vehicles over 3.5 tonnes, buses, coaches, large vans and minibuses and the Norwich LEZ which restricts buses. 60

Bath & North East Somerset Council undertook a Low Emission Zone feasibility study for Bath (completed 2014), using the government’s local air quality grant.  Most of the major road network in Bath falls within an Air Quality Management Area.  In the areas covered by the study, the national objective annual mean of 40 micrograms per cubic metre for nitrogen dioxide is exceeded by up to 20 micrograms per cubic metre (National Air Quality Regulations [Environment Act 1995]). Bath and North East Somerset Council (2014) LEZ Study, Low Emission Zone Feasibility Study for Bath, (viewed 12.01.15) [/fn]

The LEZ feasibility study tested options for stipulating Euro 5 engine emission standards for lorries, buses and coaches in the London Road / Bathwick Street area and the central area in the vicinity of the bus station, Dorchester Street, Manvers Street and St James’ Parade.

Options tested

Using 2012 as a baseline, the Low Emission Zone Feasibility Study for Bath made predictions as to the likely levels in 2015 based on 5 potential options:

  • Do Nothing: No changes assumed except Rossiter Road scheme and the effect of growth 2012-15.
  • Option 1: HGV: Only Euro-class 5 or better for the A4 London Road and Bathwick Street -24hr restriction.
  • Option 2:HGV/Bus: Only Euro-class 5 or better for London Road and Bathwick Street -24hr restriction.
  • Option 3: HGV: Only Euro-class 5 or better for London Road and Bathwick Street -between 3pm and 10am, lesser standard permitted between 10:00am-3:00pm.
  • Option 4: HGV/Bus: Euro-class 5 or better for 'Central Area' - inside A36.

Elements of study

These options were tested using the following models:

  • S-Paramics traffic model provided data for emissions and dispersion models.
  • Instantaneous Emissions Model (PHEM) - outputs estimated the total ‘source’ emission ofvarious pollutants for each link in each hour.
  • Dispersion modelling (B&NES) – ‘ADMS Urban’ provides predicted concentrations at specified points and across wider areas.

In addition the study also based its predictions on a Consultation (B&NES) with HGV operators, bus companies, neighbouring authorities and the Highways Agency and a cost benefit analysis.


Testing the five options using the models and information provided by the consultation and cost benefit analysis produced the following results/predictions:

  • Doing Nothing - NO2 emissions reduced by about 7% in ‘do nothing’ option and PM10 emissions reduced by 43% (2012-15).
  • Option 2 – NO2 emissions reduced by a further 7% and PM10 emissions reduced by a further 25%, compared to 2015 ‘do nothing’.
  • Option 4 - NO2 emissions reduced by a further 6% and PM10 emissions reduced by a further 21%, compared to 2015 ‘do nothing’.

It is important to note that the predictions are based on two key assumptions:

  • There will be no diversions as a result of the LEZ to alternative routes eg A350 through Wiltshire.
  • All vehicles in LEZ options will be fully compliant with Euro engine standard stipulations.

Some key conclusions

  • The expected changes in concentrations of NO2 are relatively negligible.
  • Turnover of the vehicle fleet towards newer vehicles with higher emission standards will inevitably occur over time, the benefits of the LEZ will diminish accordingly (unless the Euro standard of the LEZ is raised in the future).
  • Options 1, 2 or 3 will not necessarily remove any HGVs from London Road by encouraging use of alternative routes. The benefit assessed in this work is only that potentially achieved by attaining Euro 5 standard for the circa 70% of HGVs currently non-compliant now as opposed to an overall reduction in numbers as well due to diversion.
  • The Option 4 annual emissions reductions are comparable with Option 2 but, unlike the latter, are not reliant on introducing a restriction on HGVs using the Primary Road Network. Any such effect on the Primary Route Network is likely to be contested by both Wiltshire Council and the Highways Agency, as both objected to the 18 tonne weight restriction on turns between Bathwick Street and Beckford Road. As a result the study identified option 4 with a central area as the most viable option.

For more information go to - Low Emission Zone Feasibility Study for Bath