Greater exposure to PM2.5, nitrogen dioxide, and black carbon was found to be associated with a higher risk of admission to a hospital or an intensive care unit and death.
A long history of exposure to air pollution is associated with a higher risk of developing severe disease, admission to a hospital or an intensive care unit (ICU), and death by COVID-19 according to a study led by the Barcelona Institute for Global Health (ISGlobal), a research center supported by the ”la Caixa” Foundation. The study, published today (May 24) in the journal
The researchers determined the mean annual levels of fine particulate matter (PM2.5, particles with an aerodynamic diameter of =2.5 µm), nitrogen dioxide (NO2), black carbon (BC), and ozone (O3) at the residential address of each participant. They also collected data on severe cases of COVID-19 in 2020, including the number of hospital and ICU admissions, length of hospital stay, and COVID-19-related deaths. An analysis of this data revealed the following associations:
- An increase in exposure to PM2.5 of 3.2 µg/m3 was associated with a 19% increase in hospital admissions.
- An increase in exposure to NO2 of 16.1 µg/m3 was associated with a 42% increase in ICU admissions.
- An increase in exposure to BC of 0.7 µg/m3 was associated with a 6% increase in mortality.
“Our findings add further compelling evidence on the importance of reducing levels of air pollution to improve the health of the population in general and, in particular, to reduce the incidence of severe acute respiratory infections,” concludes Otavio Ranzani, ISGlobal researcher and first author of the study.
Possible Explanations for the Association
There are several biological mechanisms that may explain why long-term exposure to air pollution increases the risk of severe COVID-19.
- One hypothesis is that exposure to air pollution increases the individual’s risk of developing chronic comorbidities associated with severe COVID-19, such as hypertension.
- Another hypothesis is that air pollution may facilitate the infection, as there is published evidence that exposure to fine particulate matter increases the expression of the receptors the