Effects of Sand Dust Weather on the Air Quality of Beijing

Based on meteorological data,special observations of sand dust and environmental monitoring data,the atmospheric structure and the conditions of vertical and horizontal transport were analyzed during the strong dust storm from 19 to 22 March 2010.The changes of meteorological elements near the ground and the air quality in Beijing were also investigated.The results showed: 1) the strong dust storm was caused by cold air moving east quickly,and a cold front near the ground which clearly moved east;2) the reduction of soil moisture in the sand-dust source areas provided good conditions for sand rising;3) the dust from the source area was transported to the lower areas by the high-speed northwest airstream in the lower atmosphere;4) wind speed in the atmospheric layer of 20 m and vertical wind speed gradient both increased quickly,and the atmospheric relative humidity dropped sharply to 20%-30% during sand-dust process;5) TSP concentration over Beijing and PM10 concentration over ten counties increased obviously,and the air pollution reached a high level during the sand storm.