Science and research
Defra has an extensive programme of air quality science and research. This includes monitoring networks measuring the level of pollutants in the air; computer modelling of the levels of air pollutants to complete coverage of the UK; and research to understand how the pollutants behave in the environment.
Many pollutants or their precursors are principally the products of combustion (including emissions from power generation, traffic and shipping), industrial processes and from agricultural sources. Pollutants from these and other sources can travel long distances, and some undergo chemical reactions in the atmosphere to produce new pollutants. This can lead to air pollution problems both locally where they are released and a long way from the source, following transport of pollutants from across Europe and beyond.
There is an important distinction between emissions and concentrations of air pollutants. Emissions refer to the amount or level of pollutant released. They are generally expressed as tonnes emitted per year (or equivalent) and do not consider the composition of the air we breathe. Atmospheric concentrations of pollutants refer to the ambient levels of pollutants in the air. Unlike emissions figures which only tell us what is released into the atmosphere, atmospheric concentrations tell us to what degree pollutants are present in the air we breathe.
Air quality monitoring
Monitoring tells us the concentration of pollutants in the environment. The UK has a number of monitoring networks that measure the levels of different pollutants in the air, and the deposition of these pollutants to land and water.
Statutory air quality monitoring is undertaken in accordance with the requirements of two European Directives: the Ambient Air Quality Directive (2008/50/EC) and the Fourth Daughter Directive (2004/104/EC). The monitoring data are reported annually to the European Commission to determine compliance with limits defined in the legislation. The data are also used to establish priorities for policy development and to assess the effectiveness of control or regulatory action in reducing air pollution concentrations over time.
Information on Defra’s air quality monitoring networks, current air pollution levels, forecasts of air pollution, monitoring data, key research publications, can be found on the UK-AIR website.
Emissions database
The National Atmospheric Emissions Inventory (NAEI) compiles estimates of emissions to the air from a wide range of pollution such as road transport and industrial plants. As well as providing information on key sources of air pollution and past and future trends in emission, the inventory is an important input for modelling of pollution concentrations. The UK is obliged to report emissions of key pollutants to the European Commission and Convention on Long Range Transboundary Air Pollution annually.
Air quality modelling
Defra carries out air quality modelling both to provide information on concentrations of pollutants in places where we do not monitor and to predict concentrations under different situations, for example in the future or as a result of possible new policies. Modelling is also an important research tool. Defra uses a number of models to allow it to look at a range of pollutants and at different spatial scales, from the local to the hemispheric.
- Reports and outputs from these models can be found in the reports section of the UK-AIR website.
Further information
- For more information on air quality policy please see the Air Quality Strategy. The air quality strategy also provides information about specific air pollutants.
- The Department of Health is responsible for researching the health effects of air pollution.