Investigating inequalities in exposure to PM2.5 from wood burning

Poor air quality is one of the largest environmental threats to human health, with a broad range of pollutants contributing to air pollution. Of these, fine particulate matter, defined here as particles with an aerodynamic diameter of less than 2.5 micrometres (PM_2.5), is especially important with respect to human health. Globally, exposure to ambient PM_2.5 is estimated to cause 4.2 million early deaths a year (WHO, 2024) and in the UK 30,422-42,640 early deaths were attributable to ambient PM_2.5 exposure in 2018 (Flower et al., 2025).

PM_2.5 is emitted from a broad range of primary sources and secondary aerosol is formed in the atmosphere from gaseous precursors. In the UK wood smoke from domestic heating has been shown to be an important source of PM_2.5 in urban areas, accounting for 20% of annual average PM_2.5 mass and up to 50% of PM_2.5 mass in the winter heating season (Srivastava et al., 2025). This has led to policy interventions designed to reduce the emission of PM_2.5 from domestic combustion. To ensure policy is led by evidence, the source locations and communities exposed to PM_2.5 from wood burning need to be better understood.

Here, the spatial distribution of PM_2.5­ from wood burning was investigated in the West Midlands, the third largest conurbation in the UK. Black carbon concentrations were determined using an aethalometer mounted in a car and the Aethalometer model (Sandradewi et al., 2008) was used to estimate PM_2.5 from wood smoke in the winter heating season. Large spatial variations in PM_2.5 from wood smoke were observed and combining these measurements with socio-economic data shows that deprived communities are exposed to the highest concentrations of PM_2.5­ from wood burning. However, once population density is considered the data suggest that emissions per household may be higher in less deprived areas.

 

References

Flower G, Schneider R., Exley K., Mitsakou C., Masselot P. and Gasparrini A.: Mortality impacts of long-term PM2.5 and NO2 exposure in Great Britain under national and international air quality limits. Atmospheric Pollution Research, https://doi.org/10.1016/j.apr.2025.102827

Sandradewi J., Prevot A.S.H., Szidat S., Perron N., Rami Alfarra M., Lanz V.A., Weingartner E., and Baltensperger U.: Using aerosol light absorption measurements for the quantitative determination of wood burning and traffic emission contributions to particulate matter, Environ. Sci. Technol., 42, 33163323, 2008

Srivastava D., Saksakulkrai S., Acton W.J.F., Rooney D.J., Hall J., Hou S., Wolstencroft M., Bartington S., Harrison R.M., Shi Z., Bloss W.J.: Comparative receptor modelling for the sources of fine particulate matter PM2.5 at urban sites in the UK, Atmos. Environ., 343, 2025

World Health Organisation (WHO): Ambient (Outdoor) Air Pollution, 2024. Available at: https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health (Last accessed 18^th Dec 2025)