Notable events
| Start year | End year | Sector | Information | Impact |
| 2020 | 2020 | Road transport, aviation and railways | Because of measures in place during the COVID-19 pandemic, PM10 emissions from road transport, aviation and railways in 2020 were 21%, 61% and 27% lower than they had been in 2019 respectively. | Decrease in emissions |
| 2021 | 2021 | Road transport | As a result of easing COVID-19 restrictions, PM10 emissions from road transport in 2021 were 9.3% higher than they had been in 2021 | Increase in emissions |
The physical and chemical composition, source and particle size of airborne particulate matter varies widely. Particulate matter with an aerodynamic diameter of less than 10 micrometres (µm) is referred to as PM10. Historically, interest in particulate matter focused mainly on smoke which can cause health problems especially in combination with other pollutants. However, recent epidemiological evidence has also linked concentrations of particles in the atmosphere with human health effects. The PM10 standard was designed to identify those particles likely to be inhaled by humans, and PM10 has become a generally accepted measure of particulate material in the atmosphere in the UK and in Europe.
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.
Over the period 1990-2022, UK emissions of PM10 have decreased by 66%. The contribution of large industrial sources such as power stations and other large combustion plant burning coal and fuel oil has declined from 23% of the UK total in 1990 to 1% in 2022. The ban on the burning of crop residues after 1993 also made a notable contribution to reducing UK emissions since this source was responsible for 4% of the total in 1990. The mass emitted from road transport has also fallen since 1990, but the contribution in percentage terms has increased: from 10% in 1990 to 16% in 2022. Similarly, emissions from industrial processes have more than halved since 1990, yet the contribution that the sector makes to the UK total has increased, from 27% in 1990 to 38% in 2022. All road transport modes emit PM10, but diesel vehicles emit a greater mass of particulates per vehicle kilometre, and the proportion of road transport activity by diesel-engined vehicles has increased over time. More than 70% of the emissions within the industrial processes group are from construction and quarrying. Emissions from residential sector combustion have grown both in real terms and in terms of the contribution to the UK total. This is because of strong growth in the use of wood as a domestic fuel, which has offset reductions that have occurred due to decreasing use of coal and other solid mineral fuels.