Spatio-temporal analysis of nitrogen dioxide (NO2) from Sentinel-5P imageries using Google Earth Engine changes during the COVID-19 social restriction policy in jakarta

Abstract

The number of cases due to COVID-19 is increasing, especially in Jakarta, requiring the government to establish a policy of social restrictions. The policy impacting the mobility of people using motor vehicles becomes limited, affecting air quality such as Nitrogen Dioxide (NO2). NO2 concentrations can be determined using the Sentinel-5P satellite using Google Earth Engine. This study analyzed NO2 changes and people's mobility in residential and workplace categories through google mobility data in Jakarta spatially and temporally for January 2020 to December 2021. The Pearson's correlation (R) between NO2 from Sentinel-5P imageries and air quality monitoring stations was 0.426–0.736, indicating a moderate to strong correlation with a p-value <0.05. The decrease in NO2 occurred at the beginning of the Large-Scale Social Restriction (PSBB) from April 2020 to May 2020 and the Implementation of Restrictions on Social Activities (PPKM) policy from July 2021 to August 2021; it was −11.381 ​μmol/m2 and -23.195 ​μmol/m2, with very low and low mobility in the residential and workplace categories. The area that experienced a change in NO2 increase of 1 ​μmol/m2, the highest occurred from May 2021 to June 2021 ​at 641.571 ​km2. Meanwhile, from November 2020 to December 2020, no area experienced an increase of 1 ​μmol/m2. We discovered that there were a number of anomalies when people's mobility in the residential and workplace category was very high, NO2 actually decreased. This anomaly shows that the decrease in NO2 is influenced by decreased mobility and other factors such as precipitation.