Sulfur dioxide (SO2) trends over the urban regions of China during 2007–2020 using MERRA-2 and CAMSRA 

<p>Sulfur dioxide (SO₂) plays a key role in the formation of atmospheric sulfate that can adversely affect urban environment, human health, air quality, and the Earth&#8217;s climate system. In this talk, we present results of SO₂ trends over the 4 urban regions (YRD, BTH, PRD, and SCB) of China during 2007-2020, using the SO₂massconcentrations of the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2), and the SO₂total column of Copernicus Atmosphere Monitoring Service Reanalysis (CAMSRA). The SO₂ concentration decreased significantly during 2007-2020 over the 4 regions: YRD, BTH, PRD, and SCB, with the rate of -0.04 &#181;g.m^-3per year, -0.05 &#181;g.m^-3per year, -0.01 &#181;g.m^-3per year, and -0.03 &#181;g.m^-3 per year, receptively. Using CAMSRA data, total column of SO₂ also experienced significant decreasing trends during 2007-2020 over YRD, PRD, and SCB, with the rate of -0.15 mg.m^-2 per year, -0.05 mg.m^-2 per year, and -0.06 mg.m^-2 per year, receptively. The decreasing SO₂ levels after 2007 were mainly attributed to Chinese air pollution control policies. This work contributes to a better understanding of the impact of Chinese policies on the SO₂ level over the urban regions of China.</p>