A new study in the Netherlands has provided further evidence that exposure to higher levels of air pollution increases the risk of death from COVID-19.
After analysing data for 355 Dutch municipalities, the researchers found that an increase of just one microgram per cubic meter of fine particulate air pollution matter was linked with an increase of up to 15 COVID-19 cases, four hospital admissions and three deaths.
A single-unit increase in this fine particulate matter, also known as PM2.5, has previously been linked with an 8% rise in the coronavirus death rate in the US.
The latest study in the Netherlands found that the equivalent figure for that country could be up to 16.6%.
Writing for the World Economic Forum, researchers professor Matt Cole and assistant professor Ceren Ozgen from the University of Birmingham, and professor Eric Strobl from the University of Bern, said they had uncovered a clear correlation between air pollution and cases of COVID-19.
“The relationship we found between pollution and COVID-19 exists even after controlling for other contributing factors,” they wrote.
“If concentrations in the most polluted municipality fell to the level of the least polluted, our results suggest this would lead to 82 fewer disease cases, 24 fewer hospital admissions and 19 fewer deaths, purely as a result of the change in pollution.”
Unusually, the study found that the hotspots for coronavirus transmission in the Netherlands are in relatively rural south-eastern regions where there are fewer people living close together.
These areas hold carnival celebrations which attract thousands of people to street parties and parades, and 2020 was no exception, which could partially explain the findings.
However, the researchers highlighted how the south-eastern provinces of North Brabant and Limburg also house over 63% of the country’s 12 million pigs and 42% of its 101 million chickens.
Intensive livestock production produces large amounts of ammonia, which often form a significant proportion of fine particulate matter in air pollution. Concentrations of this are at their highest in air samples from the south-east of the Netherlands.
“The correlation we found between exposure to air pollution and COVID-19 is not simply a result of disease cases being clustered in large cities where pollution may be higher,” the researchers wrote.
“Within regions, pollution levels and COVID-19 cases can vary considerably from place to place, making it hard to estimate the precise relationship between the two.
“Being able to study this link among individual people would allow us to more precisely eliminate the influence of age and health conditions. But until this kind of data is available, the evidence of a relationship between pollution and COVID-19 can never be conclusive.”
Author: Chris Seekings
Image credit: Shutterstock