Fine Particulate Matter PM2.5

Fine particulate matter (PM2.5) is a leading risk factor for premature mortality and morbidity worldwide. According to a Global Burden of Disease Study, outdoor air pollution (including ambient particulate matter) was estimated to cause 6.67 million premature deaths in 2019. [1]

In addition, no safe threshold for PM2.5 has been identified below which no damage to health is observed. [2][3]

An abundance of evidence has supported the adverse effects of short-term and long-term ambient PM2.5 exposure on human health, even at low PM2.5 concentrations. [4]

Therefore, the latest version of the WHO global air quality guidelines published in 2021 has adjusted the recommended limit for outdoor PM2.5 exposure from 10 μg/m3 to 5 μg/m3 for the annual mean exposure and from 25 μg/m3 to 15 μg/m3 for 24-h mean exposure. [5]

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.


Murray C.J., Aravkin A.Y., Zheng P. et al.
:link: Global burden of 87 risk factors in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019.
Lancet. 2020; 396: 1223-1249

Yu W., Guo Y., Shi L., Li S.
:link: The association between long-term exposure to low-level PM2·5 and mortality in the state of Queensland, Australia: a modelling study with the difference-in-differences approach.
PLoS Med. 2020; 17e1003141

Chen J., Hoek G
:link: Long-term exposure to PM and all-cause and cause-specific mortality: a systematic review and meta-analysis.
Environ Int. 2020; 143105974

Liu C., Chen R., Sera F.
:link: Ambient particulate air pollution and daily mortality in 652 cities.
N Engl J Med. 2019; 381: 705-715

WHO global air quality guidelines: particulate matter (PM2·5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide.
Date: Sept 22, 2021
Date accessed: November 5, 2021

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