Multiple air quality monitoring evidence of the impacts of large-scale social restrictions during the covid-19 pandemic in Jakarta, Indonesia

Abstract

Air pollution is a top contributor to global mortality. Air quality issues abound in developing Asian countries, but during COVID-19 lockdowns, urban air quality improved due to the reduction in public mobility and fuel consumption. In Indonesia, the Large-Scale Social Restriction (LSSR) program was implemented to prevent the wider spread of COVID-19, especially in large urban areas. It was not a total lockdown program but had the purpose of reducing urban public mobility. This study investigated the effects of social restrictions on air quality in Jakarta, Indonesia. Data were obtained from our long-term monitoring of fine (PM2.5) and coarse particulate matter (PM2.5-10) and compositions collected at a site in South Jakarta. Other data were obtained from the environmental protection agency’s (EPA’s) air quality monitoring station in Central Jakarta including PM10, PM2.5, SO2, NO2, CO, and O3. The aerosol optical depth (AOD) in Jakarta measured by a sun photometer and satellite data were used to assess the spatial distribution of AOD across Jakarta. During the first LSSR implementation period from 15 March to 30 May 2020, there were decreased average SO2, CO, NO, NO2, and NOx concentrations of 40 to 60% compared to the same period in 2019. However, O3 increased by 33% likely due to reduction in NOx emissions. The PM2.5 decline reached ~40%, but a similar decline was not observed for PM10. Elemental and black carbon concentration data showed reductions that ranged from 30% to more than 50%. Consistent with the PM observations, both ground and satellite based AOD showed reductions in the aerosol column burden over the city. The ground based AOD values showed moderate correlations with PM2.5. The results confirmed that significant reduction in public mobility was highly associated with the improvement of local air quality which useful to derive future control strategies.