A magnetic approach for understanding the impact of Covid-19 lockdown on PM10 in Rome, Italy

The magnetic properties of PM10 daily filters collected in Rome and Latium region during and after the Covid-19 lockdown (9 March-18 May 2020) were compared for outlining the impact of the mobility restrictions on airborne particulate matter. In urban traffic sites, the average PM10 concentration levels did not significantly change after the end of the lockdown, when vehicular traffic returned to its usual levels. Conversely, the average magnetic susceptibility of PM10 daily filters approximately doubled after the lockdown, pinpointing the increase of metallic emissions related to vehicular traffic. The magnetic fraction of PM10 nearurban traffic sites was dominated by magnetite-like minerals mainly arising from brakes emissions.