The government’s annually released accredited, official air quality statistics – providing yearly updates on the concentrations of major air pollutants in the UK – have revealed that concentrations of particulate matter in the UK are at their lowest, and there is a decreasing trend of hours spent in ‘moderate’ or above particulate matter pollution.

These statistics demonstrate the continued effectiveness of industry initiatives and government policies in improving air quality across the UK, and the value of the UK’s world-leading pollution monitoring system and datasets.

As these statistics are complex, it takes time to collate, check, and analyse the large amounts of data from the UK’s over 300 monitoring sites. Due to this, the yearly statistics show us data from the year prior – so this year’s report contains information on annual concentrations of pollutants in 2024.

Concentration of pollutants vs total pollutants

When assessing our progress towards improving air quality, it is important to distinguish between the concentration of pollutants and total emissions.

Pollutant concentrations refer to the amount of a pollutant present in the air we all breathe and is measured in micrograms per cubic metre (µg/m³)

Total pollutants measure the overall quantity of pollutants monitored in the UK and is measured in kilotonnes (kt).

Both sets of data are valuable and, when delved into, help us understand areas that are improving and areas that require more attention. However, pollutant concentrations give us an accurate picture of the amount of pollutants that people will be exposed to, helping us understand the UK’s progress in improving air quality that directly affects public health.

An urban background site is a collection of data from monitoring stations located in a town or city, away from major roads and factories. The measurements at these sites show us a representative sample of pollutants that someone would be exposed to as they walked through this town or city.

Continued reductions

The official accredited government statistics reveal continued improvements in particulate matter concentrations across the UK.

The 2024 statistics show that annual mean PM2.5 concentrations at urban background sites fell to 7.15 µg/m³, the lowest level since monitoring began in 2009.

PM2.5 concentrations at urban traffic sites also fell, with the annual mean concentration being 7.53 µg/m³ – the lowest level we have on record since monitoring began.

These improvements, whilst slim, are noteworthy as they continued a long-term trend of air quality improvement. PM2.5 concentrations have fell by 42% since monitoring began in 2009.

Decreasing trend of moderate or above particulate matter pollution

Similarly, 2024’s data shows that the number of hours where concentrations are ‘moderate’ or higher for PM2.5 has also reached record lows. Further details of the government’s system for specifying pollution concentrations on a scale can be found in the report.

The most recent data shows that there has been a 98% decrease compared to 2011 in the number of hours where a monitoring site measured ‘moderate’ concentrations of PM2.5 or higher at urban background sites. Only 8 hours total were measured at ‘moderate’ or higher.

There has also been a 98% decrease compared to 2011 in the number of hours where a monitoring site measured ‘moderate’ concentrations of PM2.5 or higher at roadside.

Domestic combustion and source apportionment

This year’s official statistics acknowledged how the residential combustion of solid fuel and biomass contributes to higher levels of particulate matter in both the UK and Europe – particularly affecting concentrations during the evenings in colder seasons.

By measuring the sources of pollutants as closely as possible, the UK can appropriately tackle the source to continue our reduction of pollutant concentrations. HETAS plays a key role in this policy shaping, and advocates for the cleaner, safer, and more sustainable burning of solid fuel and biomass across the UK – setting the benchmark for best practices in installations, servicing, and ongoing use.

Differentiating inefficient, unregulated domestic burning practices such as outdoor fires, bonfires, and BBQs from household heating, and then going one step further to separate emissions from the least efficient, most polluting ways to heat your home (such as through an outdated, unmaintained appliance or an open fire) from modern, efficient, well-maintained appliances is essential. This will help our industry continue to play its part in reducing emissions.

Progress towards targets

From 2026, these annual statistics publications will also contain formal assessments of progress towards three key objectives contained with legislation and government reports:

The Air Quality Standards Regulations 2010 which requires concentrations of PM in the UK not to exceed an annual average of 40µg/m³, a 24-hour average of 50µg/m³ more than 35 times in a year for PM10, and an annual average of 20µg/m³ for PM2.5.
The Environmental Targets (Fine Particulate Matter) (England) Regulations 2023 which requires an annual average of 10µg/m³ for PM2.5 not to be exceeded at any monitoring station and population exposure to PM2.5 to be at least 35% less than what it was in 2018.
Environmental Improvement Plan 2023 which requires an annual average of 12µg/m³ for PM2.5 is not exceeded at any monitoring station and population exposure for PM2.5 is at least 22% less than what it was in 2018.

The Environmental Improvement Plan 2023 has undergone a review which is due to be published soon, so these figures are subject to change.

Current progress is positive as all targets are currently being hit – this year’s figures show urban background sites currently sit at 7.15 µg/m³ for PM2.5. Existing policies and initiatives across multiple sectors are allowing for continued progress.

Continued contribution to air quality improvements

Our industry has stepped up and worked hard to minimise its emissions, playing its part to seeing these continued reductions. Improved appliances, reaching efficiencies of up to 90% have helped households stay warm whilst minimising their emissions, and continued innovations have resulted in such impressive modern appliances. The HETAS Cleaner Choice scheme pinpoints appliances that have been independently verified as producing at least 50% less particulate matter emissions – the primary subject of scrutiny in these annual reports for our industry – than required in smoke control areas.

The success of the Ready to Burn scheme, eliminating the sale of wet wood in England, has ensured those using wood fuel to heat their home have assured access to high-quality fuels, keeping their installation safe and improving their local air quality.

Our previous analysis following the government’s annual report where they share annual total emissions (unlike these statistics, which focus on pollutant concentrations) demonstrated that emissions are continuing to fall. It is vital that we continue this hard work across industry – from manufacturer and installer to consumer – so we can all continue breathing cleaner air.

The HETAS Advice Hub provides expert, trusted guidance for stove owners on how to burn responsibly and maintain their installations, driving continued positive habits across the UK.

HETAS will continue to work with government and industry partners to promote the highest standards in solid fuel and biomass heating, ensuring our industry is doing the best is actionably can for the UK’s air quality objectives can continue to be met.

For the latest news on domestic combustion, government policy, and much more, visit our latest news pages or follow us on social.