Valutazione della genotossicità del particolato (PM2.5) nell'area di Torino durante la pandemia da COVID-19: un paragone con il periodo pre-lockdown.

In 2020, Sars-CoV-2 caused the COVID-19 pandemic. To limit virus spread, containment measures were applied in all countries (e.g. lockdown). Restrictions influenced air pollutant sources (e.g. traffic, domestic heating) and affected air quality, including particulate matter (PM), in many world area. PM is an important air pollutant and its finest fraction (PM2.5) has been classified as carcinogenic to humans. The aim of the study was to evaluate the role of lockdown and restriction measures on PM genotoxicity in four sites in Piedmont Region (Padana Plain): urban (Lingotto-Torino), traffic (Settimo Torinese), suburban (Beinasco-TRM) and rural (Dernice). Daily PM2.5 samples collected in 2020 (lockdown) were weighted and pooled according to restriction measures: January/February (no restrictions), March (lockdown), April (lockdown), May/June (low restrictions), July/August/September (low restrictions), October/November/December (medium restrictions). 2019 samples (pre-lockdown period) were pooled as 2020 samples for comparison. Organic extracts of PM2.5 were tested on human bronchial cells (BEAS-2B) to evaluate genotoxicity using comet assay. No significant difference was observed for PM2.5 concentrations and organic pollutants (benzo(a)pyrene, benzo(a)anthracene, indeno(1,2,3-cd)pyrene, benzo(b,j,k)fluoranthene) between 2020 and 2019 in all investigated sites. The results of the comet assay showed that, during lockdown months (2020), PM2.5 genotoxicity was lower in some sites (Lingotto-Torino and Beinasco-TRM sites) with respect to previous year (2019). However, in the other sites no differences were observed. During the medium restriction period (2020) some sites (Beinasco-TRM and Dernice sites) showed lower level of DNA damage than in 2019, while in the site U a higher DNA damage was observed. In conclusion, although the lockdown and the restriction measures may have contributed to reduce or modify pollutant emissions, the PM2.5 genotoxicity seems to be decreased only in some sites. This trend is probably related to the complex origin and formation of PM and to the particular conformation of Padana Plain.