Monitoring Air Quality

Across the UK there are 1500 sites monitoring air quality, co-ordinated to provide reliable measurements of air quality throughout the country. These sites are organised into networks, depending on the pollutant and the monitoring methods used. There are two major types of network; automatic and non-automatic.

Automatic monitoring networks collect and analyse a wide range of pollutants in both rural and urban locations across the UK. These networks produce hourly pollutant concentrations, with the data being collected from the individual sites electronically. The Automatic Urban Monitoring Network provides the public with rapid and reliable information on urban air quality, and satisfies the statutory requirements of EC Directives on air pollution. The Automatic Hydrocarbon Monitoring Network monitors 25 hydrocarbon species in urban air on a continuous basis, including two known carcinogens, benzene and 1,3-butadiene. The Automatic Rural Monitoring Network provides information on photochemical secondary pollution across the UK. There are 19 sites on this network, all of which monitor ozone.

Across the non-automatic networks samples are collected physically and therefore less frequently. The samples are analysed in a laboratory where the concentrations of pollutants are calculated. The Nitrogen Dioxide Diffusion Tube Network monitors nitrogen dioxide concentrations at 1200 sites across the UK. The Smoke and Sulphur Dioxide Monitoring Network, collecting information on sulphur dioxide and smoke, has been in operation since the 1960s, following the Clean Air Acts. Multi Element and Lead Monitoring Networks, since 1976, have been studying trace elements, most significantly lead, but also cadmium, copper, iron and zinc. The Acid Deposition Monitoring Network monitors rainwater acidity at 32 sites throughout the country. Two other monitoring networks include the Rural Sulphur Dioxide Monitoring Network (29 sites), and the Toxic Organic Micropollutants (TOMPS) Network (4 sites).