Wet deposition of nitrogen and sulfur in Guangzhou, a subtropical area in South China.

With the aim of understanding the seasonal distribution of deposition fluxes of nitrogen (N) and sulfur (S) in South China, a main acid deposition region in China, precipitation samples were collected and analyzed from Guangzhou area, between March 2005 and February 2006. The estimated wet deposition of N (including ammonium nitrogen (NH(4)-N) and nitrate nitrogen (NO(3)-N)) and S (sulfate sulfur (SO(4)-S)) during the monitoring period were 40.47 kg N ha(-1) and 65.29 kg S ha(-1), respectively. The average deposition of NH(4)-N was ∼1.5 times of the NO(3)-N deposition, suggesting that the reduced and oxidized N depositions were comparable in the study area. The S and N depositions in the rainy season were greater than those in the dry season, showing great seasonal variation, which was consistent with both the distribution of precipitation and the period of fertilizer application for agriculture. The N and S wet deposition fluxes in Guangzhou were greater than those in Beijing and Zhengzhou, located in the northern China, but comparable to the level of Chongqing, located in the southwestern China, another major acid deposition region. The atmospheric N and S depositions in these cities from north to south were affected by both intensive agricultural and industrial activities.