[Pollution Characteristics and Sources of Water-soluble Organic Nitrogen in PM in Jiangbei New Area, Nanjing].

The seasonal variation characteristics of water-soluble organic nitrogen (WSON) in PM were analyzed in the Nanjing Jiangbei new area. The relationship between WSON and water-soluble inorganic nitrogen (WSIN) was also discussed. The results showed that the variation range of WSON in PM was 0.446 to 4.200 μg·m, with an average value of 2.04 μg·m. This value was slightly higher than the observed results in Beijing, Shanghai, and Changzhou. The average value of WSON was the highest in autumn[(2.967±0.643) μg·m], which was approximately 1.7 times that of the other three seasons. The average contribution ratio of WSON to water-soluble total nitrogen (WSTN) in fine particles of Nanjing accounted for 25%, with high ratios in summer-autumn and low ratios in winter-spring. For example, the proportion of WSON/WSTN in winter was only approximately 50% of that in summer and autumn. WSON had the highest correlation with NO-N and the lowest correlation with NO-N in WSIN, which may be related to the volatilization of NO-N caused by high temperatures in summer. Principal component analysis (PCA) showed that WSON of PM in Nanjing was mainly derived from secondary transformation, sea salt, dust, and biomass combustion.