The concentrations and sources of fluoride in atmospheric depositions in Beijing, China

This study was carried out from June 1995 to December 1998 to explore the current status of fluoride pollution, fluoride deposition, and sources of fluoride in Beijing. The mean fluoride concentration of ambient aerosols in Beijing was 0.61 mug m(-3), with a range of 0.08 to 1.61 mug m(-3). The highest concentration (1.61 mug m(-3)) occurred in winter and was 20 times higher than in summer. This maximum concentration is to compare with annual volume-weighted average fluoride concentration in Chongqing, Sichuan Province, an area seriously polluted with fluoride. Fluoride pollution occurred in winter in Beijing, because of the increased consumption of coal for heating, which resulted also in the highest dry deposition during winter and lowest in summer. The seasonal variations in total fluoride were different from those of dry deposition. The highest total deposition was observed in summer, when 75% of the annual precipitation falls. Soil dust and coal combustion were considered the main sources of fluoride in Beijing.