A long history of exposure to air pollution is associated with a higher risk of developing severe disease, admission to hospital or an intensive care unit (ICU) and death by COVID‑19, new research indicates.

The study, led by the Barcelona Institute for Global Health (ISGlobal), was based on a large cohort of 4,660,502 adults who lived in Catalonia in 2020 – the year the Spanish autonomous community had a high incidence of COVID-19.
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,” concluded Otavio Ranzani, ISGlobal researcher and first author of the study.
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