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About Air Pollution 

For the purpose of monitoring and reporting air pollution, the UK has been divided into regions (or zones) and urban areas (or agglomerations), in accordance with EC Directive 96/62/EC.

There are sixteen regions defined for reporting levels of air pollution. They match:

  • the boundaries of England's Government Offices for the Regions; and
  • the boundaries agreed by the Scottish Executive, National Assembly for Wales and Department of the Environment in Northern Ireland.

There are twenty-eight defined urban areas (with a population greater than 250,000).  The map below shows 16 regions and 16 urban areas which are used on this site and elsewhere to report the current and forecast levels of air pollution.

Map showing the 16 regions and 16 urban areas

A detailed report on the designation of UK zones and agglomerations (PDF 8.1MB) can be downloaded from this website. From the map on the latest summary page you can select one of the sixteen regions to show the latest air pollution measurements and forecasts for that area, and then find out about the monitoring stations where the measurements are made.

Air pollution is described on a scale of 1-10 where 1 corresponds to 'Low' pollution and 10 corresponds to 'Very High' pollution.

The latest air pollution information reported here is based on results from over 120 automatic monitoring systems which take readings every hour. In addition to these, there are over 150 non-automatic monitors which sample air pollution levels on a daily, weekly or monthly basis.

You can also search to find where the automatic monitoring of air pollution is undertaken near you.

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 Pollutants (COMEAP). The system uses an index numbered 1-10, divided into four bands to provide more detail about air pollution levels in a simple way, similar to the sun index or pollen index.

  • 1-3 (Low)
  • 4-6 (Moderate)
  • 7-9 (High)
  • 10 (Very High)

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

  • Nitrogen Dioxide
  • Sulphur Dioxide
  • Ozone
  • PM2.5 Particles
  • Particles < 10µm (PM10)

The Health Bandings page provides more information.

Air Pollution Forecasts

Air Quality Forecasts are issued on a regional basis for three different area types:

  • In towns and cities near busy roads
  • Elsewhere in towns and cities
  • In rural areas

Forecasts are based on the prediction of the air pollution index for the worst-case of the five pollutants listed above, for each region.

See the Forecasting section for more information.

Page last modified: 18 January 2012