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

Based on the available literature [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] , there is enough evidence to consider the airborne route, ant specifically the role of particulate matter, as a possible additional infection "boosting" factor for interpreting the anomalous COVID-19 outbreaks observed in the Northern Italy -known to be one of the European areas characterized by the highest PM concentration [1] . Airborne transmission is certainly more effective in indoor environments, with little ventilation, but it must be considered that the Po Valley, by its atmospheric stability, closely resembles a confined environment and that long-distance virus transport is favored by high concentration of dusts. However, the highly diluted nature of viral bioaerosol in ambient air has been considered a major impediment to viral aerobiological detection -including the investigation of viral interactions with other airborne particles -despite bioaerosol is a well-known factor for the virus transmission via airborne. Recently, Groulx et al. (2018) , using an in vitro PM concentrator, suggested that the interaction between airborne viruses and airborne fine particulate matter influence viral stability and infectivity [31] . The stability of aerosol and condensation reactions occur frequently in atmosphere, as organic aerosol change the properties (hygroscopicity, toxicity, optical properties) of other aerosol [32] .