Notable events
| Start year | End year | Sector | Information | Impact |
| 2020 | 2020 | Road transport and aviation | Because of measures in place during the COVID-19 pandemic, PM2.5 emissions from road transport and aviation in 2020 were 22% and 60% lower than they had been in 2019 respectively. | Decrease in emissions |
| 2021 | 2021 | Road transport | As a result of easing COVID-19 restrictions, PM2.5 emissions from road transport in 2021 were 8% higher than they had been in 2020 | Decrease in emissions |
| 2022 | 2022 | Aviation | As a result of easing COVID-19 restrictions, PM2.5 emissions from aviation in 2022 were 101% higher than they had been in 2021. | Increase in emissions |
| 2017 | Ongoing | Domestic combustion | From 2017 to 2021 Ecodesign‑compliant (“Ecodesign Ready”) stoves entered the UK market voluntarily, driven by manufacturers and industry schemes. After 1 January 2022 Ecodesign became mandatory for all new domestic solid‑fuel room heaters placed on the UK market and these continue to replace older, less efficient, stoves. | Decrease in emissions |
| 2021 | Ongoing | Domestic combustion | The Air Quality (Domestic Solid Fuels Standards) (England) Regulations 2020 regulate the sale of solid fuels for domestic burning in England, banning traditional house coal, setting emissions limits for manufactured solid fuels, and restricting the sale of wet wood through controls on log size and moisture content, with ongoing impacts on the English fuel market. | Decrease in emissions |
Particulate matter with an aerodynamic diameter of less than 2.5 micrometres (µm) is referred to as PM2.5.
PM can be emitted directly from a source (primary PM) or formed through the interaction of other pollutants (secondary PM). The National Atmospheric Emissions Inventory estimates emissions of primary PM only.
In general, emissions of finer particulates follow similar trends as for PM10. UK emissions of PM2.5 have declined by 75% since 1990 due mainly to a reduction in coal use, and the banning of crop residue burning in 1993. Emissions from coal-fired power stations have fallen by almost 100% since 1990. Residential sector emissions fell by 76% between 1990 and 2009, before increasing by around 11% to 2019, and have since resumed a downward trend. As other sources of emissions have declined, those from domestic combustion have become an increasingly important, as the share of emissions in 2024 (20%) is similar to the share of emissions in 1990 (19%). Industrial use of biomass fuels is increasing and has, as a result, become a more significant contributor to UK emissions, 17% of UK emissions of PM2.5 in 2024.
Emissions of PM2.5 in 2024 are 1% below the 2030 National Emissions Ceilings Regulations and Gothenburg Protocol targets.