[Characteristics and Source Apportionment of Water-soluble Ions in Dry Deposition in the Summer and Autumn of Nanjing].

A total of 84 effective dry deposition samples were collected from July to October, 2014 in Nanjing, and the chemical composition and source apportionment of water-soluble ions dry deposition in the summer and autumn season were discussed. The results indicated that the average pH was 6.2, and the dry deposition samples usually appeared neutral. Ca and NH were the major cations and their average daily concentrations were 115.7 μeq·L and 31.2 μeq·L,accounting for 68.3% and 18.6% of total cations, respectively. SO, Cl and NO were the main anions, and their average daily concentrations were 30.4, 20.7 and 18.7 μeq·L, a total of 89.2% of the total anions, respectively. High temperature and humidity of meteorological factors and contaminated air mass affected dry deposition. Local air mass had greater impact on dry deposition pollution, which indicated that dry deposition pollution had local property. In summer and autumn seasons in Nanjing, the stationary sources had more contributions to atmospheric dry deposition of water-soluble ions than mobile sources, while the environmental control measures for the Nanjing Youth Olympic Games had greater effect on stationary sources than mobile sources. Studies of the origins of major ions indicated that SO and NO were mostly attributed by the anthropogenic activities, and Cl was mainly from ocean sources, while K and Mg were mostly from the terrestrial input.