The Potential role of Particulate Matter in the Spreading of COVID-19 in Northern Italy: First Evidence-based Research Hypotheses

Leonardo Setti; Fabrizio Passarini; Gianluigi De Gennaro; Pierluigi Barbieri; Maria Grazia Perrone; Andrea Piazzalunga; Massimo Borelli; Jolanda Palmisani; Alessia Di Gilio; PRISCO PISCITELLI; Alessandro Miani

by an airborne droplet transmission as described by Wellings and Teunis (2004) for the epidemic curves for Sever Acute Respiratory Sindrome (SARS) during the outbreak on February-June 2003 in Hong Kong, Vietnam, Singapore and Canada [28] . In Rome the growth rate before the lockdown measures (March 13 th ) was 0,27 per day with a doubling time of 2.6 days that were comparable with a "superspread event" as described for SARS. In Milan the growth rate was significantly higher, close to 0.34 per day with a doubling time of 2.0 days, and suggests a R 0 value higher than 6.0 quite similar to the epidemic transmission by airborne droplets observed for measles (known to be around 12-18) [29] and to the highest R 0 estimates documented for China, ranging from 1.4 to 6.49 with a mean of 3.28 and a median of 2.79 (Wuhan: 2.55-2.68; Hubei Province: 6.49; China: 2.2-6.47) [30] .