Air quality in the State of Sao Paulo was evaluated during the first general State plan of mobility restrictions due to the COVID-19 pandemic (24th March to May 31, 2020). Nitrogen dioxide (NO2), ozone (O-3), particulate matter PM10 and PM2.5 and sulphur dioxide (SO2) concentrations were assessed in cities of the Sao Paulo State with a monitoring station and compared to historical data. Linear regression models...