Declining precipitation acidity from H2SO4 and HNO3 across China inferred by OMI products. (1st March 2020)

• Record Type: Journal Article
• Authors: Zhang, Xiuying; Zhao, Limin; Xu, Junfeng; Chen, Dongmei; Wu, Xiaodi; Cheng, Miaomiao
• Is Part Of: Atmospheric environment. Volume 224(2020)
• Publication Date: 2020-03-01
• Subjects: Precipitation acidity -- OMI SO2 and NO2 columns -- China; Air -- Pollution -- Periodicals; Air -- Pollution -- Meteorological aspects -- Periodicals; 551.51
• DOI: 10.1016/j.atmosenv.2020.117359
• Languages: English
• ISSNs: 1352-2310

Abstract

Abstract: The long-term trend of precipitation acidity (PA) resulting from H2 SO4 and HNO3 is analysed across China from 2005 to 2016 based on Ozone Monitoring Instrument (OMI) SO2 and NO2 columns, measured precipitation amounts, and ground measurements of SO4 2− and NO3 − concentrations in precipitation. PA showed substantial variations across China, exhibiting an average of 0.88 keq ha −1 yr −1 in 2016. The spatial variation in SO4 2− deposition than that in NO3 − deposition was closer to the spatial variation in PA, contributing 78.7% of the PA throughout China. Eastern China had significantly higher PA values than western China with four hotspots in the Yangtze River Delta (YRD) and Pearl River Delta (PRD), northern China (NC) and the Sichuan Basin (SCB). In eastern China, the PA values increased by 5.0% between 2005 and 2007 and then decreased by 34.3% in 2016, while the PA values in western China increased by 14.7% between 2005 and 2012 and then decreased by 2.0% in 2016. For the four hotspots, the SO4 2− to NO3 − ratio (S/N) decreased; moreover, the PA decreased in NC, PRD and SCB but slightly increased in the YRD. Highlights: Eastern China has higher PA than Western China. PA in China is mainly contributed from SO4 2− deposition. PA reaches the maximum in 2007 in eastern China, while in 2012 in western China. The PA values in NC, PRD, and SCB decreased, but slightly increased in YRD.