Acute and chronic exposure to air pollution in relation with incidence, prevalence, severity and mortality of COVID-19 : a rapid systematic review
Date
2021-04-10
Journal Title
Journal ISSN
Volume Title
Publisher
BMC
Abstract
Background: Air pollution is one of the world’s leading mortality risk factors contributing to seven million deaths
annually. COVID-19 pandemic has claimed about one million deaths in less than a year. However, it is unclear
whether exposure to acute and chronic air pollution influences the COVID-19 epidemiologic curve.
Methods: We searched for relevant studies listed in six electronic databases between December 2019 and
September 2020. We applied no language or publication status limits. Studies presented as original articles, studies
that assessed risk, incidence, prevalence, or lethality of COVID-19 in relation with exposure to either short-term or
long-term exposure to ambient air pollution were included. All patients regardless of age, sex and location
diagnosed as having COVID-19 of any severity were taken into consideration. We synthesised results using harvest
plots based on effect direction.
Results: Included studies were cross-sectional (n = 10), retrospective cohorts (n = 9), ecological (n = 6 of which two
were time-series) and hypothesis (n = 1). Of these studies, 52 and 48% assessed the effect of short-term and longterm
pollutant exposure, respectively and one evaluated both. Pollutants mostly studied were PM2.5 (64%), NO2
(50%), PM10 (43%) and O3 (29%) for acute effects and PM2.5 (85%), NO2 (39%) and O3 (23%) then PM10 (15%) for
chronic effects. Most assessed COVID-19 outcomes were incidence and mortality rate. Acutely, pollutants
independently associated with COVID-19 incidence and mortality were first PM2.5 then PM10, NO2 and O3 (only for
incident cases). Chronically, similar relationships were found for PM2.5 and NO2. High overall risk of bias judgments
(86 and 39% in short-term and long-term exposure studies, respectively) was predominantly due to a failure to
adjust aggregated data for important confounders, and to a lesser extent because of a lack of comparative analysis.
Conclusion: The body of evidence indicates that both acute and chronic exposure to air pollution can affect
COVID-19 epidemiology. The evidence is unclear for acute exposure due to a higher level of bias in existing studies
as compared to moderate evidence with chronic exposure. Public health interventions that help minimize
anthropogenic pollutant source and socio-economic injustice/disparities may reduce the planetary threat posed by
both COVID-19 and air pollution pandemics.
Description
CITATION: Katoto, P. D. M. C., et al. 2021. Acute and chronic exposure to air pollution in relation with incidence, prevalence, severity and mortality of COVID-19 : a rapid systematic review. Environmental Health, 20:41, doi:10.1186/s12940-021-00714-1.
The original publication is available at https://ehjournal.biomedcentral.com
The original publication is available at https://ehjournal.biomedcentral.com
Keywords
Long-term air pollution, COVID-19 (Disease), Mortality -- Risk factors, Pollution
Citation
Katoto, P. D. M. C., et al. 2021. Acute and chronic exposure to air pollution in relation with incidence, prevalence, severity and mortality of COVID-19 : a rapid systematic review. Environmental Health, 20:41, doi:10.1186/s12940-021-00714-1