The impact of stay-home policies during Coronavirus-19 pandemic on the chemical and toxicological characteristics of ambient PM in the metropolitan area of Milan, Italy.

The goal of this study was to characterize changes in components and toxicological properties of PM during the nationwide 2019-Coronavirus (COVID-19) lockdown restrictions in Milan, Italy. Time-integrated PM filters were collected at a residential site in Milan metropolitan area from April 11th to June 3rd at 2020, encompassing full-lockdown (FL), the followed partial-lockdown (PL2), and full-relaxation (FR) periods of COVID-19 restrictions. The collected filters were analyzed for elemental and organic carbon (EC/OC), water-soluble organic carbon (WSOC), individual organic species (e.