南京市江北工业区降水酸性及化学成分分析

The Analysis of Precipitation Acidity and Chemical Composition in the Industrial Estate Located on North Bank of the Yangtze River,Nanjing

于2005年9月─2006年8月在南京市江北地区南京信息工程大学校园内采集降水样品共59个,测定pH和电导率,用离子色谱仪检测样品的阴、阳离子浓度.结果表明：pH为4.17～8.34,酸雨频率为49.2%,电导率为1.1～42.5 mS/m;阴离子为F^-,Cl^-,NO2^-和NO3^-,SO4^2-,阳离子为Na^＋,K^＋,Mg^2＋,Ca^2＋和NH4^＋;主要阴、阳离子分别为SO4^2-,NO3^-,NH4^＋和Ca^2＋,并存在季节性变化.ρ（SO42-）/ρ（NO3-）的年均值为4.21,表明酸雨仍为硫酸型.南京市工业区的大气污染物主要是燃煤过程中排放的SO2等气体.

A total of 59 precipitation samples were collected on an event basis from September 2005 to August 2006 at Nanjing University of Information Science ＆ Technology, which is in the north part of Nanjing. The pH and electric conductivity were measured. Concentration of ions and cations were determined by ion chromatography. The conclusions were as follows： The pH ranged from 4.17 to 8.34; the frequency of acid rain was 49.2% ; the electric conductivity changed in a range of 1.1 ～ 42.5 mS/m. Anions in the rain contained F^- , Cl^- , NO2^ - , NO3^- and SO4^2- , and especially SO4^2- and NO3^- were primary; cations were Na^＋ , K^＋ , Mg^2＋ , Ca^2＋ , NH4^＋ , and NH4^＋ and Ca^2＋ took the most part. They all varied with season time. The annually averaged ratio of p （SO4^2- ）/p （NO3^-） was 4.21, so the acid rain here belonged to sulphate-dominated type. The dominant atmospheric pollutant in this industrial estate was SO2 , discharging form the process of burning coal.