Long-term trends of ozone precursors and ozone sensitivity in Jakarta Metropolitan Area: A view from space

Jakarta Metropolitan Area (JMA) is an urban agglomeration in Indonesia where the air quality has dramatically changed from relatively clean to polluted. Economic growth, increased population, and village-to-city expansion marked the development of Jakarta and the satellite cities surrounding it, such as Bogor, Depok, Tangerang, and Bekasi. In line with human activities, large amounts of air pollutants are emitted and affect human health and vegetation. Ozone (O-3) is a secondary air pollutant formed from volatile organic compounds (VOCs) and nitrogen oxides (NOx). This study aims to investigate the long-term trend of ozone precursors and ozone sensitivity in JMA from space. Trends analysis is studied using quantile regression. We used NO2 and formaldehyde (HCHO) column density from the Ozone Monitoring Instrument (OMI) aboard Aura Satellite from 2011 to 2022. Ozone sensitivity is derived from the ratio of HCHO and NO2 (FNR). The results show an upward trend in HCHO and a slight NO2 downward over JMA. In general, FNR changed from a predominantly VOC-limited regime in urban JMA to a transitional regime suggesting control of VOC and NOx is needed to reduce ozone concentration. Meanwhile, FNR in suburban and rural areas such as Bogor is toward a more NOx-limited regime.