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Changes in air quality during and after large-scale social restriction periods in Jakarta city, Indonesia

Rendana Muhammad, Idris Wan Mohd Razi, Rahim Sahibin Abdul

Acta Geophysica

2022

Vol. 70, no 5

2161--2169

COVID-19 outbreak has constrained human activities in Jakarta, Indonesia during the large-scale social restriction (LSSR) period. The objective of this study was to evaluate the changes in the spatial variation of air pollutants over Jakarta during and after the LSSR periods. This study used satellite retrievals such as OMI, AIRS, and MERRA-2 satellite data to assess spatial variations of NO2, CO, O3, SO2, and PM2.5 from May to June 2020 (during the LSSR period) and from July to August 2020 (after the LSSR period) over Jakarta. The satellite images were processed using GIS software to increase the clarity of the images. The relationship between air pollutants and meteorological data was analyzed using Pearson correlation. The results showed the levels of NO2, PM2.5, O3, and CO increased by 59.4%, 21.2%, 16.2%, and 1.0%, respectively, while SO2 decreased by 19.1% after the LSSR period. The temperature value was inversely correlated with PM2.5, NO2, and SO2 concentrations. Furthermore, the backward trajectory analysis revealed that air pollutants from outland areas such as the east and southeast carried more particulate matter and gases pollutants, which contributed to the air pollution during and after the LSSR periods. As a whole, the COVID-19 outbreak had bad impacts on human health, but the increase in air pollutants levels after loosening the LSSR policy could also lead to a higher risk of severe respiratory diseases. This study provides new insight into air pollutant distribution during and after LSSR periods and recommends an effective method of mitigating the air pollution issues in Jakarta.

Variability in aerosol optical properties at Hornsund, Spitsbergen

Rozwadowska A., Sobolewski P.

Oceanologia

2010

No. 52 (4)

599-620

Spectra of the aerosol optical thickness from the AERONET station at Hornsund in 2005-2008 were employed to study the interseasonal and intraseasonal variability in aerosol optical thickness for λ=500 nm (AOT(500)) and the Angström exponent in the southern part of Spitsbergen in spring and summer. The dependences of aerosol optical properties on long-range transport and local meteorological conditions, i.e. wind direction and speed and humidity, were analysed. Backward trajectories computed by means of NOAA HYSPLIT model (Draxler & Rolph 2003) were used to trace the air mass history. The mean values of AOT(500) for spring and summer were 0.110 ± 0.007 (mean and standard deviation of the mean) and 0.048 ± 0.003 respectively. The average values of the Angström exponent do not differ and take respective values of 1.44 ± 0.03 and 1.45 ± 0.03. In both seasons, the highest AOT(500) cases (the highest 20% of AOT values) can be explained by long-range transport from Europe, Asia (spring and summer) and North America (summer). In summer, the impact of distant sources on AOT is strongly modified by cleansing processes en route to Hornsund. Local meteorological conditions at the station are of secondary importance as regards the intraseasonal variability of aerosol optical properties in the southern part of Spitsbergen.