Air Quality During Mobility Restrictions in Sao Paulo State Municipalities

Abstract

The air quality in the state of Sao Paulo was evaluated during the first general State plan of mobility restrictions due to COVID-19 pandemics (24th March to 31st May 2020). Nitrogen dioxide (NO2), ozone (O3), particulate matter with a diameter of less than 10 μm (PM10) and 2.5 μm (PM2.5) and sulphur dioxide (SO2) concentrations were assessed in all cities of the Sao Paulo state with a monitoring station and compared to historical data. Linear regression models were built to quantify the linear relation between the isolation index and the concentration of each pollutant during the studied period. There was a significant reduction of SO2 and NO2 concentrations in 2020 compared with the historical data due to the influence of social isolation in 50% and 67% of the monitoring stations, respectively. On the contrary, O3 and PM 10 concentrations increased in 21% and 35% of the stations, respectively (especially in urban areas affected by vehicle traffic and industrial production). Generally, it was possible to observe positive environmental impacts and improved air quality during mobility restrictions, with reductions in the concentration of pollutants in most monitoring stations compared to historical data. This study intends to contribute to future discussions on the effects of implementing restriction measures and other air quality policies on the global environment.