Model study of atmospheric particulates during dust storm period in March 2010 over East Asia

Abstract

A Regional Air Quality Model System (RAQMS) is utilized to investigate the spatial and temporal distributions of PM10 concentrations and soil dust aerosol over East Asia in March 2010, when a severe dust storm occurred on 19-23 March. Dust aerosols were primarily generated in Gobi Deserts on 19 March and then swept across vast areas of East Asia. Model results are verified by in-situ observations from 17 Chinese cities, satellite retrievals, as well as lidar measurements in Japan. Validations demonstrate a good skill of RAQMS in representing the distribution and variation of PM10 concentrations and the major features of dust storm evolution. In general, the model performs better in the eastern parts of China than that in the western parts of China. Monthly mean surface PM10 concentrations were above 400 μg m-3 in west China, about 200-400 μg m-3 in north and central China, and below 100 μg m-3 in the remaining parts of China and East Asia. Dust aerosol was the major contributor to PM10 mass concentration during the study period, accounting for more than 80% in west China, 30%-60% in north and central China, and about 20%-40% in south China and the western Pacific regions. The dust storm in March 2010 was unique in its influential extent and transport pathway because it impacted as far as the Pearl River Delta of China, such as Hong Kong. Interannual variability of dust budget is analyzed, showing the dust emission, deposition and atmospheric loading in March 2010 are all larger than those in 2002 and 2006. Of the total dust emission (110.4 Mt), about 68% was redeposited onto the underlying surface by dry and wet deposition processes, and the remaining 32% was suspended in the atmosphere or subject to long-range transport. © 2011 Elsevier Ltd.