UK Air Quality Objectives

Air Quality Standards and Objectives are set because there is medical evidence that exposure to certain air pollutants over a period of time can have a detrimental effect on health (based on current scientific knowledge).

Some pollutants (such as Benzene and 1,3-Butadiene) are known carcinogens at certain exposures, however we do not believe there is anywhere in Cheshire East where concentrations are above the recommended level.  Other pollutants such as Nitrogen Dioxide are known to be a respiratory irritant and has both acute short term and chronic long term effects, particularly in those with pre-existing conditions.

The table below shows the key pollutants and the relevant UK air quality objectives (the objective for nitrogen dioxide and particulates is highlighted).  There are two objectives given representative of long and short term exposure.  This is because the potential heath effects of any pollutant depend on the concentration, and length of time you are exposed.  If you are exposed to a low concentration, for a short period of time it is unlikely there would be any noticeable effect, whereas the same concentration over a longer period of time could have an effect on your health.

For more details on how air pollution could impact your health, go to our Air Quality Health Advice page.

Air Quality Objective Concentrations Table
PollutantAir Quality Objective
Concentration
Measured asTo be achieved by
Benzene  
All authorities 16.25 µg m-3 Running annual mean 31 December 2003
England and Wales Only 5.00 µg m-3 Annual mean 31 December 2010
Scotland and N. Ireland 3.25 µg m-3 Running annual mean 31 December 2010
1,3-Butadiene 2.25 µg m-3 Running annual mean 31 December 2003
Carbon Monoxide      
England, Wales and N. Ireland 10.0 mg m-3 Maximum daily running 8-hour mean 31 December 2003
Scotland Only 10.0 mg m-3 Running 8-hour mean 31 December 2003
Lead 0.5 µg m-3 Annual mean 31 December 2004
  0.25 µg m-3 Annual mean 31 December 2008
Nitrogen Dioxide

200 µg m-3 not to be exceeded more than 18 times a year

1-hour mean

31 December 2005

  40 µg m-3 Annual mean 31 December 2005
Sulphur dioxide 350 µg m-3, not to be exceeded more than 24 times a year 1-hour mean 31 December 2004
  125 µg m-3, not to be exceeded more than 3 times a year 24-hour mean 31 December 2004
  266 µg m-3, not to be exceeded more than 35 times a year 15-minute mean 31 December 2005
Particles (PM10) (gravimetric)  
All authorities

50 µg m-3, not to be exceeded more than 35 times a year

Daily mean

31 December 2004

  40 µg m-3 Annual mean 31 December 2004
Scotland Only 50 µg m-3, not to be exceeded more than 7 times a year Daily mean 31 December 2010
  18 µg m-3 Annual mean 31 December 2010
Particles (PM2.5) (gravimetric) * 25 µg m-3 (target) Annual mean 2020
All authorities 20% cut in urban background exposure Annual mean 2010 - 2020
Scotland Only 12 µg m-3 (limit) Annual mean 2020
PAH * 0.25 ng m-3 Annual mean 31 December 2010
Ozone * 100 µg m-3 not to be exceeded more than 10 times a year 8 hourly running or hourly mean* 31 December 2005

Table reproduced from DEFRA Air Quality Archives.

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