Do atmospheric pollution and fine particulate matter aggravate COVID-19?

On observing a coincidence between larger COVID-19 clusters and atmospheric pollution in the first pandemic wave, in Wuhan, China, then in Northern Italy, researchers began to associate severe cases with elevated levels of atmospheric pollutants in heavily populated industrial regions. Fine and ultra fine particles in particular were suspected of carrying and spreading the virus and aggravating the disease. Data acquired in recent months show that chronic PM and NO2 pollution, rather than their peaks, are associated with case numbers and severe forms of the disease. There are two possible explanations: an increase in pulmonary inflammation among individuals already weakened by an overexpression of the ACE2 receptor under the effect of chronic pollution, and the idea that atmospheric particles transport SARS-CoV-2, which has not yet been demonstrated.