Our air quality is monitored by a national network of monitoring sites, which continuously captures ambient air quality levels for selected pollutants throughout the UK.  This monitoring helps to assess the risks to people’s health and to the environment.

 Statistics can be derived for the average number of days when pollution is moderate or higher.

Air quality statistics in the UK, 1987 to 2011 – Final: Statistical release

The statistics are based on concentrations of pollutants and the resulting ‘pollution days’ for the following:

carbon monoxide (CO)
nitrogen dioxide (NO₂)
ozone (O₃)
particulates (PM₁₀)
sulphur dioxide (SO₂)

At the moderate level, the effects of pollution may start to be noticeable to people with respiratory and other health problems, with greater risks to health at higher levels.

Number of days when air pollution is moderate or higher in the UK, 1987 to 2011 (final)

• Days of moderate or higher air pollution in urban areas have shown a long-term improvement but increased in 2011: average days declined from a peak of 59 days in 1993 to 16 days in 2011, but increased from the lowest recorded level of 8 days in 2010. 
• Days of moderate or higher air pollution for rural areas have shown no clear trend but increased in 2011:  average days declined from a peak of 64 days in 2003 to 30 days in 2011, but increased from a low of 22 days in 2010.

Data download

The key facts publication contains a downloadable version of this page
Next scheduled update April 2012
Additional data and information on particulates, ozone  and other pollutants.
Air quality monitoring networks and methodology
Government policy on air quality
Air quality in Scotland, Wales, Northern Ireland and Europe