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Pollutants and health

Air pollution has a range of effects on health. However, air pollution in the UK on a day-to-day basis is not expected to rise to levels at which people need to make major changes to their habits to avoid exposure; Nobody need fear going outdoors, but they may experience some noticeable symptoms depending on which of the following population groups they are in.

The World Health Organisation identified seven key pollutants as being of possible concern and has set target level against which they may be assessed. A summary of these is given below. In Wiltshire only nitrogen dioxide (NO 2) and fine particulates (PM10) are of concern.

Pollutant Source of pollution Health effect
Benzene Unburnt fuel in petrol vehicle exhausts and fuel evaporation during refueling and industrial solvent use. Human carcinogen, possible link to leukaemia in significant concentrations and long term exposure.
1,3-Butadiene Formed during the combustion of petrol and diesel. Industrial chemical plant and the manufacture of synthetic rubber tyres. Human carcinogen if prolonged exposure to high concentration. Prevents normal transport of oxygen by the blood.
Carbon Monoxide Incomplete combusion of fuel Can result in confusion, reduced coordination, reduced mental performance and death in high concentration.
Lead Industry No permanent damage at low exposure concentrations. Impaired mental function and neurological damage in children.
Nitrogen dioxide Nitric oxides derived predominantly from motor vehicles but also from other combustion and power generation processes. Irritates lungs, lower resistance to respiratory infections.
Fine Particles (PM 10) Wide range of natural and manmade sources major local sources include road traffic - combustion, brakes and tyres. Particles enter lungs can cause inflammation and a worsening of heart and lung conditions.
Sulphur dioxide Erosion of soils, agriculture and quarrying. Produced when sulphur containing fuel burned. Major source in UK is power stations. Reduced lung function in asthmatics. Respiratory impact.

Carbon dioxide (CO 2), a commonly quoted air pollutant, is notably absent from the above list. It is not included in the above table because whilst having climate change impacts it does not affect respiration directly.

Index and Bands

In the UK most air pollution information services use the index and banding system approved by the Committee on Medical Effects of Air Pollution Episodes (COMEAP). The system uses 1-10 index divided into four bands to provide more detail about air pollution levels in a simple way, similar to the sun index or pollen index.

The overall air pollution index for a site or region is calculated from the highest concentration of five pollutants:

For more information about the Boundaries Between Index Points for each Pollutant, visit the Defra UK-AIR Daily Air Quality Index page.

Health Advice

Latest studies report that:

Air pollution can cause short-term health effects to sensitive individuals (people who suffer from heart disease or lung diseases, including asthma). Effects on sensitive people can be reduced by spending less time outdoors. 'Reliever' inhalers should lessen effects on asthma sufferers.

How to use the Daily Air Quality Index

Step 1: Determine whether you (or your children) are likely to be at risk from air pollution. Information on groups who may be affected is provided on the Additional information on the short-term effects of air pollution page on the Defra UK-AIR website. Your doctor may also be able to give you advice.

Step 2: If you may be at-risk, and are planning strenuous activity outdoors, check the air pollution forecast page.

Step 3: Use the health messages corresponding to the highest forecast level of pollution as a guide.

Air Pollution Banding Value Accompanying health messages for at-risk individuals* Accompanying health messages for the general population
Low 1-3 Enjoy your usual outdoor activities. Enjoy your usual outdoor activities.
Moderate 4-6 Adults and children with lung problems, and adults with heart problems, who experience symptoms, should consider reducing strenuous physical activity, particularly outdoors. Enjoy your usual outdoor activities.
High 7-9 Adults and children with lung problems, and adults with heart problems, should reduce strenuous physical exertion, particularly outdoors, and particularly if they experience symptoms. People with asthma may find they need to use their reliever inhaler more often. Older people should also reduce physical exertion. Anyone experiencing discomfort such as sore eyes, cough or sore throat should consider reducing activity, particularly outdoors.
Very High 10 Adults and children with lung problems, adults with heart problems, and older people, should avoid strenuous physical activity. People with asthma may find they need to use their reliever inhaler more often. Reduce physical exertion, particularly outdoors, especially if you experience symptoms such as cough or sore throat.

* Adults and children with heart or lung problems are at greater risk of symptoms. Follow your doctor's usual advice about exercising and managing your condition. It is possible that very sensitive individuals may experience health effects even on Low air pollution days. Anyone experiencing symptoms should follow the guidance provided on the Defra UK-AIR website.

Boundaries Between Index Points for Each Pollutant

Visit the UK-Air website to view the boundaries between each index points for common pollutants measured.


There is little evidence that air pollution itself causes asthma. However, if you already have asthma, you may find that air pollution triggers an attack, although infections and allergens are more likely to do so.  On days where pollution is high you should carry your medication with you, and avoid strenuous exercise.  There may be more benefit taking preventative medication on these days.  If in doubt, please see your GP.

In winter

If traffic fumes make breathing harder, avoid busy streets as much as you can.  If you are elderly, stay indoors as much as possible and keep warm.

In summer

If you find it harder to breathe on hot sunny days, avoid energetic outdoor activities, especially in the afternoons when pollution levels tend to be higher.  If your child has asthma, they should still be able to take part in games as normal, but they may need to use their reliever inhaler more before they start.  They do not need to stay away from school.


Smoking is likely to have a much more serious effect on your health (and that of others around you) than ambient air pollution. Giving up smoking will reduce your risk of lung and heath disease considerably and is the single most important thing you can do to improve your health. It will also make you less vulnerable to the short-term effects of air pollution.

Using the Wiltshire Stop Smoking Service is the most effective way to quit smoking for good. With our help you will be up to four times more likely to succeed in quitting compared to trying it alone and going ‘cold turkey’.

If you want help to stop smoking we provide free friendly, individual support and advice by qualified stop smoking advisors. Find your nearest venue or get quit support over the telephone by calling 0300 003 4562.

Visit the NHS Choices website for more information on treatments to help you stop smoking or for further details of the benefits of stopping visit the NHS Smokefree website.

National and local strategies to improve air quality and health

Joint Strategic Needs Assessment

The Joint Strategic Assessment for Wiltshire (JSA) is the primary document for bringing together data on topics including housing, economy, health, children and young people and the environment. It identifies Wiltshire’s priorities in a single succinct report.

The JSA is an example of partnership working across Wiltshire, with contributions from each of the thematic delivery partnerships. The JSA is intended to support commissioning decisions and the developments of strategic and local community plans. The document has informed the new four year council Business Plan 2013- 2017.

Air Quality is a significant determinant of health and is recognised as an indicator within the JSA.

Wiltshire Community Area JSAs

Building on the JSA programme for Wiltshire, new community level JSAs have been produced for all of the 18 community areas. These documents set out the strategic issues for community areas based on local level data, information and knowledge and are a key step in identifying the needs of the Wiltshire population. Air quality has been identified as a priority for a number of community areas and is recognised within their community level JSA.

Wiltshire State of Environment Report

In May 2012, a State of the Environment Report was published for Wiltshire and Swindon, produced by Wiltshire Wildlife Trust in partnership with NHS Wiltshire and Wiltshire Council. It constitutes a strategic assessment for the environment as part of the suite of Joint Strategic Assessments.

The report builds on the environment chapter of the 2010/2011 Joint Strategic Assessment (JSA) for Wiltshire and contains information on Wiltshire’s air quality.

Public Health Outcomes Framework

The public health outcomes framework, originally published in January 2012 by Public Health England, sets out the desired outcomes for public health and how these will be measured. The framework concentrates on two high-level outcomes that set the vision to be achieved across the public health system. These are:

The significant domain in relation to improving air quality is Health Protection as air pollution is specifically listed as an indicator.