SoNaRR 2025: Air

Air as a resource refers to the quality of the air around us in Wales and the emissions we produce including pollutants and radioactive substances.

Key messages

• Clean air and places free from noise and light pollution are essential for public health, biodiversity, and economic prosperity in Wales, with air pollution estimated to cause 1,000-1,400 premature deaths annually and cost the country £1 billion per year in lost workdays and healthcare expenses.
• Despite improvements since the industrial era, parts of Wales still have some of the worst air quality in Britain, with major pollution sources including transport, agriculture, industry, and domestic burning.
• The Welsh Government has demonstrated a strong commitment to improving Wales’s air resource through the Clean Air Plan for Wales and the introduction of the Environment (Air Quality and Soundscapes) (Wales) Act 2024
• Addressing air and noise pollution in Wales requires a multi-sector, collaborative approach that integrates nature-based solutions, sustainable transport, and emissions control across various industries.
• Improving Wales’s air will benefit public health and ecosystem resilience, as well as promoting sustainable economic growth through cleaner technologies and practices.

Assessment of SMNR

This air assessment is one of three natural resource and eight ecosystem assessments that inform the overall SoNaRR2025 report. It builds on the findings of SoNaRR2020, drawing together updated evidence from subject experts, national datasets, and collaborative projects and an ammonia specific case study.

The assessment is structured around four interlinked aims that guide Wales’s progress toward the sustainable management of natural resources (SMNR), helping to communicate the relationship between the environment, well-being, and the economy.

Aim 1: Stocks of natural resources are safeguarded and enhanced

Air quality in Wales has shown mixed progress. Emissions of key pollutants such as sulphur dioxide (SO₂), nitrogen oxides (NOₓ), particulate matter (PM₁₀ and PM_2.5), and lead (Pb) have declined significantly since 2005, largely due to shifts in energy production and transport technologies. For example, SO₂ emissions from power stations fell by 99% due to the transition from coal to cleaner energy sources. However, ammonia (NH₃) emissions have increased, driven by agricultural intensification, including greater use of urea-based fertilisers and livestock housing. The Environment (Air Quality and Soundscapes) (Wales) Act 2024 introduces the requirement to set a new national target for PM_2.5 and for at least one other pollutant, aiming to further reduce emissions.

Efforts to enhance air quality include legislative actions, urban planning, and technological improvements. Initiatives such as Clean Air Zones, active travel promotion, and improved energy efficiency in housing are expected to reduce emissions. Localised air pollution however remains a concern, particularly in urban and industrial areas.

Tranquillity mapping indicates that 69% of the country is in the top three national tranquillity categories for the sound environment where natural sounds are more prominent than noise when considering solely road and rail.

Aim 2: Ecosystems are Resilient to Expected and Unforeseen Change

Air pollution poses significant risks to ecosystem resilience. NO_X and NH₃ contribute to nitrogen deposition, leading to eutrophication, soil acidification, and water pollution. In 2021, 99.1% of sensitive habitats areas in Wales exceeded their critical load for eutrophication, and 70.6% exceeded acidity thresholds. Although the magnitude of exceedance has declined over time, all Special Areas of Conservation (SACs) and Special Protection Areas (SPAs) still exceed nutrient nitrogen critical loads for at least one feature.

Progress includes reductions in SO₂ emissions, which are expected to relieve acidification pressures by 2050. The Control of Agricultural Pollution Regulations (2021) aim to reduce ammonia emissions and nutrient losses. Coordinated efforts to manage nitrogen pollution are essential for restoring ecosystem health. Actions such as sustainable agriculture and pollution management are being implemented to mitigate air-related impacts on biodiversity and habitat quality.

Aim 3: Healthy Places for people, protected from environmental risk

Air pollution significantly affects human health, contributing to respiratory and cardiovascular diseases. In Wales, between 1,000 and 1,400 deaths annually are attributed to poor air quality. Pollutants like NO₂, SO₂, PM_2.5, and ozone (O₃) are particularly harmful. Noise pollution also impacts well-being, with 27% of urban residents reporting regular disturbance. Cleaner air and quieter environments improve physical and mental health, reduce healthcare costs, and enhance quality of life.

Environmental inequalities persist, with deprived communities more exposed to poor air quality and limited green space. In 2019, Newport and Cardiff had the highest concentrations of areas in the most deprived physical environment category. The 2024 Act and urban planning initiatives aim to address these disparities through integrated approaches, including nature-based solutions and active travel infrastructure, fostering healthier, more equitable living conditions.

Aim 4: Contributing to a Regenerative Economy, Achieving Sustainable Levels of Production and Consumption

Air quality is closely linked to economic activity. Agricultural intensification has driven increases in ammonia emissions, while industrial and transport sectors have seen reductions. Poor air quality affects productivity, with estimated losses of £1 billion annually in Wales. Ground-level ozone, formed from NO₂, damages crops, ecosystems, and materials, adding socio-economic costs.

Efforts to transition to a regenerative economy include reducing emissions through cleaner transport, sustainable agriculture, and improved infrastructure. The Environment (Air Quality and Soundscapes) (Wales) Act 2024 sets targets for PM_2.5 and potentially other pollutants such as NO₂ and NH₃, supporting long-term sustainability. Research into pollution management and resource efficiency is vital for aligning economic growth with environmental protection, ensuring air quality contributes positively to Wales’ future prosperity.

Key changes since SoNaRR2020

Since SoNaRR 2020, Wales has seen notable progress in air quality. Concentrations of nitrogen dioxide have declined in many urban areas, leading to the revocation of several AQMAs. However, ammonia and ozone levels remain problematic, especially for sensitive habitats.

A major legislative shift came with the Environment (Air Quality and Soundscapes) (Wales) Act 2024, which empowers Welsh Ministers to set pollutant-specific targets (e.g. PM₂.₅, NO₂, ammonia) and includes requirements such as active travel promotion to reduce emissions. In regard to industrial sources of air pollution the closure of the blast furnaces at Port Talbot is expected to reduce emissions, especially of PM₁₀ and PAHs, measurable improvements are likely to become clearer in 2025–2026 as monitoring continues.

While emissions have broadly dropped, air pollution still poses risks to health and ecosystems. Integrated action across sectors is now key to meeting health and biodiversity goals.

Read the full Air assessment in our State of Natural Resources Report 2025.

Underlying evidence

In writing our assessments and to better identify opportunities for action we have gathered evidence that helps us understand these key aspects:

• the drivers of change and pressures on air in Wales.
• the state and trends of state of the air in Wales.
• the benefits and dis-benefits provided by air in Wales, depending on its state, and the impacts these can have on human well-being and ecosystems.

Access the detailed evidence through our SoNaRR 2025 Evidence portal.

View full screen version

Evidence needs

Wider monitoring to support modelling: While existing monitoring and modelling meet statutory reporting requirements, expanding pollutant monitoring - such as ammonia – would strengthen the evidence base and support national modelling.

Health impacts: Additional research on the effects of emerging air pollutants of concern such as ultrafine particulates, PFAS and microplastics may help the understanding of potential impact and the development of effective mitigation strategies.

Odour impacts: Evidence of odour impacts in Wales and understanding the national and local scale issues and what are the main issues and from what sectors.

Noise impacts: Greater understanding of soundscapes and how effective soundscapes can enhance human health and ecosystems.

Emissions reduction: Research into the effectiveness of strategies that incorporate emission reductions would help validate those approaches and inform future policy decisions.

Ecosystem impacts: Up to date site habitat monitoring data would help improve understanding of how air pollution affects biodiversity and designated sensitive features. Additional evidence on the impact of air pollution on crop yields would also support more informed decision-making.

Read SoNaRR 2025 Evidence needs.

Key evidence sources

Explore some of the evidence we have used to inform our assessment:

• SoNaRR 2020 Air Quality assessment
• National Atmospheric Emissions Inventory
• Tranquillity and Place Maps
• Dark Skies
• Environmental Noise mapping
• Area affected by acidity and area affected by nitrogen, UK Biodiversity Indicators
• UK Natural Capital Accounts
• Critical Load and Critical Level exceedances in the UK 
• National Survey for Wales
• Air Quality in Wales Reports
• Air Pollution Trends Report 2024: Critical Load and Critical Level exceedances in the UK
  
  

Case studies

Monitoring and reducing ammonia

Ammonia is a major atmospheric pollutant and is harmful to human health when combined with other industrial pollutants. When deposited on land, ammonia can acidify soils and freshwaters, ‘over-fertilising’ natural plant communities. The extra nitrogen can increase the growth of some species such as rough grasses and nettles, which out-complete other species. This project aims to monitor and reduce ammonia emissions from agriculture and is funded through the Welsh Government’s Nature Networks Programme.

Natural Resources Wales / Project to monitor and reduce ammonia emissions from agriculture

Agricultural drivers of NH3 emission pressures and their impacts in Wales

This case study explores how we might better understand the relationships between the agricultural drivers of ammonia (NH3) emission pressures and their impacts in Wales using a Driver-Pressure-State-Impact-Response (DPSIR) model. It shows how this evidence can help better target responses to reduce NH3 emission from agriculture, and highlights potential barriers to widespread adoption of these response measures.

SoNaRR Case Study NH3

The Environment (Air Quality and Soundscapes) (Wales) Act 2024

The Environment (Air Quality and Soundscapes) (Wales) Act 2024 – essentially Wales’ “Clean Air Act” – was passed in February 2024 (Senedd Cymru, 2024; Welsh Government, 2024a). This Act sets a framework for implementing the Clean Air Plan and stricter air quality targets (notably PM₂.₅), enables creation of Clean Air Zones in the future, and tackles emissions from domestic burning and idling.

Environment (Air Quality and Soundscapes) (Wales) Act 2024 | Law Wales