Mortality impacts of long-term PM2.5 and NO2 exposure in Great Britain under national and international air quality limits

Abstract

PM_2.5 and NO₂ are two of the most dangerous air pollutants, contributing to substantial excess mortality across Europe. In 2021, the World Health Organization (WHO) revised its air quality (AQ) guidelines, decreasing the recommended annual limit from 10 μg/m³ to 5 μg/m³ for PM_2.5, and from 40 μg/m³ to 10 μg/m³ for NO₂.

In this study, we analysed concentrations and associated long-term premature mortality across Great Britain from 2008 to 2018 in relation to multiple AQ limits, as determined by WHO guidelines and international/national regulations.

The percentage of the population exposed to PM_2.5 concentrations above 10 μg/m³ decreased from 67.6 % to 38.2 % over the study period, whereas those exposed to NO₂ levels above 40 μg/m³ remained low. Levels below the new, lower WHO guidelines for PM_2.5 and NO₂ were reached in only a handful of locations.

Exposure to PM_2.5 in 2018 resulted in 36,403 (30,422–42,640) premature deaths, whereas NO₂ exposure contributed to 20,175 (7125–32,281) premature deaths. These numbers could be reduced by 46 % and 44 %, respectively, if exceedances beyond the lower cut-offs were avoided.

These findings indicate that complying with the new WHO recommendations would require considerable effort, but they can lead to substantial health benefits.