Could pollution affect COVID-19 lethality?

A study in the journal Environmental Pollution found a correlation between air pollution and death rates from COVID-19 in Italy. In Lombardy and Emilia-Romagna, which both have high levels of pollution, the lethality rate was 12%. In the rest of the country, the rate was around 4.5%.

When discussing why this relationship might appear, the authors explain that “[a]ir pollution represents one of the most well-known causes of prolonged inflammation, eventually leading to an innate immune system hyper-activation.”

However, they note that there may be other ways to explain these differences. For instance, it may be due to the way each region records deaths and infections or because Lombardy and Emilia-Romagna have relatively older populations.