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Atmospheric sulfur deposition in East China was studied using the Regional Acid Deposition Modeling System (RegADMS) with a horizontal resolution of 75 km. A one-year run was performed for the year 2000. As a result, the annually averaged Vd for SO2 and SO42- are 0.34 and 0.27 cm s-1, respectively. The calculated Vd for SO2 and SO42- at Yingtan agreed well with the semi-measurements. And the modeled Vd over different land-use types were generally in agreement with those reported from the references. The sub-grid scale (25 x 25 km) method (SSM) was proven to better describe the dry deposition process and save computational time when estimating dry deposition velocity (Vd) than the coarse grid scale (75 x 75 km) method. The estimated total deposition of sulfur in East China is 2.22 x 106 ton yr-1. Dry deposition accounts for almost 55% of the total deposition and more than 90% of sulfur was deposited on the soil-plant ecosystem. There was evident regional distribution of sulfur depositions in the provinces of the studied area, with most values more than 3 ~ 5 g m-2 yr-1. [ABSTRACT FROM AUTHOR]

Air quality data from city clusters in the fast developing Yangtze River Delta (YRD) region of China during 1996 - 2003 were analyzed, with a cross-border transport study using the Regional Acid Deposition Model System (RegADMS). Investigations show that the annual average concentrations of SO2, NO2, PM10 are 12 ~ 64, 13 ~ 57, and 79 ~ 184 µg m-3, respectively. As the primary air pollutants in the target area, surface NO2 levels increased by 13% while PM10 levels decreased by 39% from 1996 to 2003. The surface SO2 concentration showed fluctuations during the study period, reaching a minimum in 1999 and rising again in 2003. Acid rain still remains an important atmospheric environmental issue. The frequency of acid rain was about 23.5 ~ 36.7%, and the pH value of precipitation ranged from 5.09 to 5.48, with little change in these years. Modeling studies indicated that sulfur deposition and nitrogen deposition were in the ranges 0.5 ~ 10 and 0.2 ~ 5 g m-2 yr-1, respectively; these levels exceed the critical load in some regions. The trans-boundary transport of sulfur deposition and nitrogen deposition due to SO2 and NOx emission among city clusters (Shanghai and the other 8 cities in Jiangsu Province, including Nanjing, Wuxi, Changzhou, Suzhou, Nantong, Yangzhou, Zhenjiang, and Taizhou) in the YRD region was significant. The emission from Shanghai contributes 5% ~ 29% of sulfur deposition and 3% ~ 30% of nitrogen deposition in the 8 cities, while the 8 cities contribute 27.5% of sulfur deposition and 20.2% of nitrogen deposition in Shanghai. [ABSTRACT FROM AUTHOR]