Air pollution research
This page contains information on some of Defra’s air pollution research programme including impacts on vegetation and ecosystems and air pollution deposition.
Information on other areas of air pollution research including publications is available on the UK-AIR website.
Impacts of air pollution on ecosystems
Atmospheric pollution can adversely affect the natural environment in a number of ways.
Pollutants such as sulphur dioxide and nitrate cause acidification (for example via ‘acid rain’), which can cause significant damage to both living and non-living components of ecosystems. Eutrophication occurs when pollution delivers an excess of nutrients to ecosystems resulting in decreased biodiversity, for example by causing algal blooms in rivers and lakes which can wipe out fish populations.
Pollutants such as ozone and nitrogen can directly cause toxic damage to all living ecosystem components, and particularly to plants. Deposited heavy metals are stable and persistent environmental pollutants which cannot be degraded or destroyed. As such they may accumulate in soil, water and sediments and cause damage to both the environment and human health.
All of these effects result in significant subsequent impacts on both biodiversity and ecosystem services.
The extent of these impacts are assessed using critical loads and levels, which are estimates of the concentration of one or more air pollutants above which there is risk of damage to the environment. The term ‘critical load’ refers to the deposition of pollutants from the air to land and water, while ‘critical level’ refers to pollutant concentrations in the atmosphere.
Research projects
Defra has a number of research projects investigating the effects of air pollution on vegetation and ecosystems.
UK Acid Waters Monitoring Network
The UK Acid Waters Monitoring Network (UKAWMN) monitors the impacts of acid deposition on freshwater ecosystems in sensitive areas of the UK, and assesses their recovery following policies to reduce emissions of acidifying pollutants. The network has been monitoring lakes and streams for over 20 years, and is beginning to show the success of policy controls.
Freshwater Umbrella
The Freshwater Umbrella research programme investigates the impacts of eutrophying and acidifying pollutants on freshwater ecosystems in the UK.
Research on the Eutrophication and Acidification of Terrestrial Ecosystems
The UKREATE programme (UK Research on the Eutrophication and Acidification of Terrestrial Ecosystems), also known as the Terrestrial Umbrella, investigates the impacts of air pollution on UK terrestrial ecosystems. In particular it focuses on experiments investigating the impacts to vegetation of nitrogen deposition, and the development and testing of models to predict likely future impacts under different scenarios.
Ozone Umbrella
The Ozone Umbrella investigates the effects of ground level ozone on vegetation in the UK. In addition to the toxic damage to plants caused by ozone, the Ozone Umbrella assesses the implications of ozone pollution for related issues including flooding, drought, food security and biodiversity.
Research into Modeling and Mapping Ozone Deposition and Stomatal Flux (the way in which ozone enters and damages plant leaves), is being carried out to accurately simulate the impacts of ozone on vegetation under different conditions.
The new DO3SE (Deposition of Ozone and Stomatal Exchange) model is being developed to replace less accurate concentration-based methods of estimating damage to vegetation and crops from ground-level ozone.
Critical Loads and Dynamic Modelling
Critical loads maps and datasets provide a national picture of the areas at risk from the harmful effects of acidification and eutrophication. The UK National Focal Centre (UK NFC) for critical loads modelling and mapping co-ordinates mapping activities and compiles critical loads datasets.
The dynamic modeling of critical loads project investigates the response of ecosystems to changing emissions of pollutants and enables the timescales of chemical change and of species change in damaged environments. A related project addresses the estimation of critical loads for heavy metals and recovery timescales.
Air Pollution Deposition Monitoring
The UK Eutrophying and Acidifying Atmospheric Pollutants (UKEAP) network measures air pollutants at rural sites across the UK. The UKEAP network contributes data on the flow of chemicals in the environment. This is a component of both UK and international research in the field. This in turn supports the effort to understand climate and ecosystem responses to anthropogenic and biogenic emissions, and the assessment of climate, ecosystem and human impacts of acidifying and eutrophying air pollutants.
European Monitoring and Evaluation Programme
The European Monitoring and Evaluation Programme (EMEP) is an international cooperative programme operating under the UNECE Convention on Long-Range Transboundary Air Pollution.
EMEP assesses the transport across Europe of:
- acidification and eutrophication
- the formation of ground level ozone
- persistent organic pollutants (POPs)
- heavy metals
- and particulate matter.
The UK has two ‘supersites’, one in the north of the UK at Auchencorth Moss in Scotland, and one in the south at Harwell in Oxfordshire.
These monitor changes in background levels of a very wide range of air pollutants and are used for occasional intensive campaigns coordinated across Europe. Air pollution measurements from other rural sites are also reported to EMEP.
Heavy metal monitoring
The heavy metals deposition network measures background concentrations and deposition of heavy metals at rural sites. Data collected at the monitoring sites are analysed and used to create maps of the UK showing the concentrations and deposition of heavy metals in both air and precipitation. These maps are used to identify the areas where the metal deposition is most likely to cause a pollution effect.