Fig. 1.

The geographical distribution of air pollution (AQI) and the role of health, environmental, and socio-economic factors on SARS-CoV-2 mortality (SMR) in Italy. (A) SMR values of Northern Italian regions are much higher than in the Southern regions. (B) The situation is strikingly similar when considering pollution over the Italian Peninsula; for this representation, Air Quality Index (AQI) is used as a proxy of pollution (where high values mean higher pollution). AQI and SMR values are in percent. (C) The agreement between the SMR actual values and the Random Forests predictions (R² = 0.95), which follows a positive linear trend; in the smaller panel: the importance of the different factors with AQI ranking as the most important one. (D) Also when individually analysed (colours of points and lines as in the in part C’s inset), AQI is the only factor showing a significant (P < 0.05, Bonferroni correction) and positive correlation with SMR (R² = 0.54). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)