A1: Emissions for five key air pollutants

Final Final

Short description

This indicator shows changes in the emissions of the 5 key air pollutants: sulphur dioxide (SO2), fine particulate matter (PM2.5), nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC) and ammonia (NH3). Air pollution has negative impacts on human health and the environment. Long-term exposure to particulate matter contributes to the risk of developing cardiovascular diseases and lung cancer. As well as being emitted directly, particulate matter can be formed in the atmosphere from reactions between other pollutants, of which SO2, NOx, NMVOCs and NH3 are the most important. NOx and NH3 emissions can be deposited in soils or in rivers and lakes, for example, through rain. Resulting nutrient nitrogen deposition affects the nutrient levels and diversity of species in sensitive environments, for example, by encouraging algae growth in lakes and water courses and by producing ozone (O3) which damages crops and leads to impacts on wildlife through enhanced nutrient levels. This indicator is an assessment of pressures on the atmosphere caused by the emissions of 5 key pollutants, which when concentrated in the air or deposited have impacts on human health and ecosystems.

Data are published annually in the Air Quality Pollutant Inventories 1990-2018.

Trend description

Emissions for all 5 key air pollutants (ammonia, fine particulate matter, nitrogen oxides, non-methane volatile organic compounds and sulphur dioxide) in England have fallen over the latest 20 years for which annual, country-level data are available. Emissions of SO2 have seen the greatest reductions, falling by 92% between 1998 and 2018. Emissions of NMVOCs and NOx have both fallen by 63%, and emissions of PM2.5 and NH3 have fallen by 32% and 14% respectively over the same time period. More recently, the trends in annual emissions of PM2.5 and NMVOC have levelled off and emissions of NH3 have increased. For PM2.5, decreases in emissions from many sources have been partially offset by increases in emissions from residential burning (domestic combustion); emissions of PM2.5 from this source increased by 56% between 2007 and 2018.


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This table provides metadata for the interim or final indicator presented above.

Indicator name

Emissions for five key air pollutants

Indicator reference


Outcome Indicator Framework theme


Headline indicator status

Air quality

Relevant goal(s) in the 25 Year Environment Plan
  • Clean air
  • Thriving plants and wildlife
Relevant target(s) in the 25 Year Environment Plan
  • Meeting legally binding targets to reduce emissions of five damaging air pollutants
  • Restoring 75% of our one million hectares of terrestrial and freshwater protected sites to favourable condition, securing their wildlife value for the long term
Position in the natural capital framework
  • Pressure on natural capital assets
Related reporting commitments
  • Emissions Reduction Commitments for the UK
Geographic scope


Status of indicator development


Date last updated

11 June 2021