COVID-19 Pandemic: Impacts on Air Quality during Partial Lockdown in the Metropolitan Area of São Paulo

Air pollution has become one of the factors that most affect quality life, human health, and environment. Gaseous pollutants from motor vehicles have a significantly harmful effect on air in Metropolitan Area São Paulo (MASP)—Brazil. Motor emit large amounts particulate matter (PM), carbon monoxide (CO), nitrogen oxides (NOx), volatile organic compounds (VOCs), last three acting as main tropospheric ozone (O3) precursors. In this study, we evaluated effects these MASP during partial lockdown was imposed to ensure social distancing necessitated by COVID-19 pandemic. We compared monthly data for dioxide (NO2) Ozone Monitoring Instrument (OMI) CO, SO2, BC MERRA-2 period between April May 2020 (during pandemic) with average same (pre-pandemic) years 2017 2019 southeast region Brazil. The meteorological pollutant concentration CETESB monitoring stations were diurnal cycle previous years, regard averages (2017, 2018, 2019) 2020, when first Our findings showed there decrease NO2 concentrations ranging 10% more than 60% Rio de Janeiro (MARJ), whereas Belo Horizonte Vitoria (MABH MAV, respectively), reduction around 10%. case CO MERRA-2, considerable (approx. 10%) caused throughout almost entire state Paulo, particularly bordering Janeiro. SO2 5 lower MARJ west MABH, 30 50% border states Janeiro, while MAV region, an increase levels, not affected Sharp reductions hourly (38.8%), NO (44.9%), (38.7%), PM2.5 (6%) noted at rate pre-pandemic period. contrast, approximately 16.0% O3 urban areas are seriously vehicular emissions, which is probably related NOx.