Change characteristic of atmospheric particulate mercury during dust weather of spring in Qingdao, China

Abstract

Atmospheric aerosol samples were collected during dust weather of spring from 2008 to 2011 in Qingdao, in which the concentrations of atmospheric particulate mercury (PHg) were measured to analyze its distribution characteristics and source. PHg concentration during the study ranged from 0.050 ng m−3 to 0.788 ng m−3 with the average 0.292 ng m−3 in dust day, while 0.085 ng m−3 to 0.444 ng m−3 with the average 0.188 ng m−3 in non-dust day. PHg concentration in dust day is far higher than that in some cities of South Korea and Japan and comparable to some cities in China. There was a statistically power function between PHg/TSP and TSP concentrations, which meant that intense dust (high TSP) brought particles with low mercury content. The estimated dry deposition flux of PHg is 0.9–14.2 ng m−2 h−1 with the mean 5.26 ng m−2 h−1 in dust day. The mercury deposition flux in a dust day accounts for almost 1% annual flux, which should be paid attention in the regional and global cycle of mercury. The trajectories are categorized into 4 sectors. Cluster 1 and cluster 4 were the main routes of dust to Qingdao, coming from Kazakhstan and north of Mongolia individually. There is higher TSP, and lower PHg/TSP in dust of cluster 4 compared with cluster 1, because of longer transport distance and faster movement speed. There is highest PHg/TSP in cluster 2 because of passing polluted East China. The slow transport speed, long stay at polluted developed region caused pollutants to accumulate in the aerosols. Differences of transport route, movement speed affects the mercury content significantly.