Air quality is an important public health issue in Wales. This research briefing examines the main sources of air pollution, how air quality is monitored and regulated, the health effects of pollution, and how pollution levels have changed over time.
Air pollution can be caused by both human activity and natural processes. Major pollutants such as particulate matter, nitrogen oxides, and ozone, are continuously monitored across Wales. The main human sources of air pollution include transport, domestic burning, industry, electricity production, and agriculture.
Health effects of air pollution
The burden of poor air quality is equivalent to around 1,000 to 1,400 deaths each year in Wales. A large body of evidence shows that air pollution can cause negative health outcomes, including respiratory and cardiovascular diseases, cancer, adverse pregnancy outcomes, and effects on cognitive health. Exposure and risk are not evenly distributed, with some groups and communities more affected than others. Wider social and economic consequences include pressures on the NHS and the interaction between pollution and existing inequalities.
Government approaches to improve air quality
Action at both the UK and Wales level has sought to limit the production of air pollution and people’s exposure to that pollution. Notable legislative milestones include the Environment Act 1995 and the Environment (Air Quality and Soundscapes) (Wales) Act 2024 (the 2024 Act). Legislation empowers and obliges the Welsh Government and local authorities to act to reduce air pollution, including by declaring Air Quality Management Areas and smoke control areas, and introducing policies to bring pollution below legal thresholds. In 2026, the last Welsh Government used powers in the 2024 Act to set targets for reducing fine particulate matter pollution. The Welsh Government has also acted to reduce pollution from domestic burning, agriculture, and transport.
Air pollution trends in Wales
Concentrations of many major pollutants, including sulphur dioxide, nitrogen dioxide, and particulate matter, have fallen substantially in recent decades. Continuing challenges include urban ozone pollution and local variation in exposure. It can be challenging to isolate the specific impact of individual policy measures. Case studies focussing on Port Talbot steelworks closure and 50 mph speed limits on trunk roads illustrate how local air quality can change in response to industrial and transport developments. Action to reduce greenhouse gas emissions can also have a co-benefit of reducing air pollution, and therefore improving human and environmental health.
Research briefing by Charlotte Morgan and Dr Matthew Sutton, Senedd Research, Welsh Parliament
Senedd Research acknowledges the parliamentary fellowship provided to Charlotte Morgan by the Engineering and Physical Sciences Research Council (EPSRC) which enabled this briefing to be completed.
