上海大气氮湿沉降的污染特征

为探讨上海大气氮湿沉降的污染特征,采集了2007年11月至2008年10月上海雨水样品,分析了大气氮湿沉降浓度,探讨了上海大气湿沉降氮通量及上海市区,市郊和远郊大气氮湿沉降的时空污染特征.结果表明:(1)上海市区、市郊和远郊大气氮湿沉降质量浓度平均值分别为2.96、2.31、2.21 mg/L.从上海大气湿沉降总体来看,大气氮湿沉降劣V类、V类的超标率分别达到51.09%和13.87%.推断大气氮湿沉降的主要来源是机动车辆所排放的大量氮氧化物.(2)除冬季外,其余季节上海市区大气氮湿沉降浓度均大于市郊和远郊;市区和远郊大气氮湿沉降浓度均在秋季最大,市郊大气氮湿沉降浓度在春季最大.(3)上海大气年氮湿沉降通量为78.42 kg/hm~2,同其他区域相比较,属于世界上高氮沉降区域.(4)上海大气月氮沉降通量与月平均降雨量呈显著的线性正相关(p<0.05),说明上海大气氮湿沉降通量主要受降雨量的影响.

Contamination characteristics of nitrogen in rainwater of Shanghai

For exploring the contamination characteristics of nitrogen (N) in rainwater of Shanghai, nitrogen concentrations in rainwater samples collected in Shanghai from 2007.11 to 2008. 10 were determined. The fluxes of atmospheric nitrogen wet deposition and the spatio-temporal variations of nitrogen in rainwater were studied. The re-sults showed that rainwater in Shanghai was high contaminated by nitrogen;the rainwater could graded by V or inferi-or V grades of surface water quality compared to the national standard. From the spatial variations of nitrogen con-tents,urban rainwater nitrogen contents were higher than those of suburban as well as rural rainwater. Exhaust gas of vehicles was the main source of nitrogen in rainwater. Nitrogen wet deposition fluxes in autumn were relatively higher than other seasons. The nitrogen flux by wet deposition was 78.42 kg/hm~2 annually in Shanghai. The correlation a-nalysis indicated that nitrogen fluxes were mainly controlled by precipitation.