“…A number of ACTRIS studies related to the COVID-19 pandemic and the series of lockdowns over Europe investigated their impact on air quality both at the European (Putaud et al, 2023), country (Petetin et al, 2020;Putaud et al, 2021) and city scales, e.g. Athens (Eleftheriadis et al, 2021), Paris (Petit et al, 2021), Elche (southeastern Spain) (Clemente et al, 2022), the Po Valley (Cristofanelli et al, 2021), and rural Košetice in the Czech Republic (Mbengue et al, 2023). Interestingly, most studies above documented not only an overall decrease in submicron particulate matter concentrations and primary traffic tracers, but also an increase in ozone.…”