Under Part IV of the Environment Act 1995, local authorities have a duty to review and assess certain air quality pollutants in their areas against national air quality objectives set out in the The Air Quality Strategy for England, Scotland, Wales and Northern Ireland. Air quality objectives are maximum concentrations of pollutants in ambient air, averaged over a defined time period. They are set on the basis of what is considered to be acceptable in terms of what is scientifically known about the effects of each pollutant on health and on the environment. The objectives also take into account other factors such as economic efficiency, practicability, technical feasibility and timescale. It is important to note that air quality objectives only apply at outdoor locations where members of the public are regularly present over the appropriate averaging period – a concept known as relevant exposure.
The air quality objectives relevant to local authorities in England are set out in the Air Quality (England) Regulations 2000, as amended by the Air Quality (England) (Amendment) Regulations 2002.
Air quality objectives relevant to local authorities exist for the following pollutants:
|
Pollutant |
Main sources of emissions in Salford (based on 2014 data)* |
National air quality objective(s) and averaging period |
|
|---|---|---|---|
|
Long term |
Short term |
||
|
Nitrogen dioxide (NO2) |
Road transport: 77%
Domestic & commercial Combustion: 11%
Rail: 10% |
40 µg/m3 measured as an annual mean.
|
200 µg/m3 measured as a 1 hour mean, not to be exceeded more than 18 times a year. |
|
Fine particles less than 10 microns in diameter (PM10) |
Road transport: 89%
Domestic & commercial Combustion: 5%
Industrial processes: 2% |
40 µg/m3 measured as an annual mean.
|
50 µg/m3 measured as a 24 hour mean, not to be exceeded more than 35 times a year. |
|
Sulphur dioxide (SO2) |
Domestic & commercial Combustion: 52%
Land use change, forestry & agricultural combustion: 30%
Rail: 17%
|
- |
266 µg/m3 measured as a 15 minute mean, not to be exceeded more than 35 times a year.
350 µg/m3 measured as a 1 hour mean, not to be exceeded more than 24 times a year.
125 µg/m3 measured as a 24 hour mean, not to be exceeded more than 3 times a year. |
|
Carbon monoxide (CO) |
Road transport: 71%
Domestic & commercial Combustion: 25%
Air transport: 3% |
- |
10 mg/m3 measured as a maximum daily 8 hour mean. |
|
Lead |
Industrial processes: 99%
Large commercial boilers: 1% |
0.25 µg/m3 measured as an annual mean. |
- |
|
Benzene |
Land use change, forestry & agricultural combustion: 52%
Domestic & commercial Combustion: 43%
Large commercial boilers: 2% |
5 µg/m3 measured as an annual mean. |
- |
|
1,3 –butadiene |
Road transport: 100% (2008 data) |
2.25 µg/m3 measured as a running annual mean. |
- |
* The data is from the atmospheric emissions inventory for Greater Manchester (EMIGMA). This contains information on emissions of pollutants identified in The Air Quality Strategy for England, Scotland, Wales and Northern Ireland from all identifiable sources in the area.
Information about the health and environmental effects of individual pollutants can be found from the central government UK Air and Clean Air Greater Manchester websites. The exact risk of exposure to air pollutants is difficult to quantify. The true exposure of individuals in Salford will depend on several factors such as the distance and infrastructure separating people from the pollution source, the amount of time outside, exposure to indoor pollutants (at home and at work) and the quality of indoor ventilation systems.
National air quality policy guidance states that concentrations of benzene, 1,3-butadiene, lead and carbon monoxide have been well below objective levels for several years and national monitoring is currently providing a sufficient basis for the review and assessment of these pollutants.
Air quality reviews are undertaken in two stages:
Where air quality objectives are not likely to be achieved in areas where there is relevant exposure, local authorities are required to designate an air quality management area (AQMA) for the relevant pollutant and produce an action plan to reduce ambient air pollution in those areas.
Local Authorities are also expected to work towards reducing emissions and concentrations of very fine particles (PM2.5) in their local area as practicable. The Greater Manchester Low Emissions Strategy and Air Quality Action Plan will contribute to reducing PM2.5 emissions.
This page was last updated on 9 April 2019