There is “compelling” evidence that air pollution significantly increases coronavirus infections, hospital admissions and deaths, according to the most detailed and comprehensive analysis to date.
The research indicates that a small, single-unit increase in people’s long-term exposure to pollution particles raises infections and admissions by about 10% and deaths by 15%. The study took into account more than 20 other factors, including average population density, age, household size, occupation and obesity.
There is growing evidence from Europe, the US and China that dirty air makes the impact of Covid-19 worse. But the study of the outbreak in the Netherlands is unique because the worst air pollution there is not in cities but in some rural areas, due to intensive livestock farming.
This allows the “big city effect” to be ruled out, which is the idea that high air pollution simply coincides with urban populations whose density and deprivation may make them more susceptible to the virus.
The scientists are clear they have not proven a causal link between air pollution and worse coronavirus impacts. Conclusive evidence will only come with large amounts of data on individual people, which is not yet available, rather than average data for regions as used in the analysis.
But scientists said it was important to do the best research possible as understanding the link may be important in dealing with further Covid-19 outbreaks and could signal where subsequent waves will hit the hardest.