2007—11-15—2007—12-31期间在南京北郊南京信息工程大学设立采样点,对出现的6次浓雾过程进行了分时段雾水样品采集,并使用ICS·2000离子色谱仪和IRIS IntrepidⅡ等离子体发射光谱仪测定了雾水中5种水溶性阴离子和14种金属元素浓度.结果表明,南京6次浓雾过程雾水pH值在4.64~6.88之间;水溶性阴离子平均浓度以SO4^2-最高(2864.9μmol·L^-1),其次是Cl^-(1584.4μmol·L^-1)和NO3-(736.0μmol·L^-1);含量较高的金属元素有Ca、K、Na、Mg、Al和Zn;雾水重金属元素Cu、Ni、Pb、Cd和Cr的平均浓度分别为2.30、1.46、0.42、0.41和0.37μmol·L^-1;雾水金属元素浓度在雾的初始时段表现较高,随着雾的持续发展出现不同程度降低,但日出后的上班早高峰时段又出现很明显的升高;雾水NO2-浓度值表现为夜间浓度较高而日出后浓度很低或消失,夜、昼变化非常大;通过对比雾水和雨水pH平均值发现,雾水pH平均值是6.20,雨水pH平均值为4.91,小于酸雨指标值5.6,酸度较强;雾水电导率是雨水的10.5倍,雾水的重金属元素Cd、Cr、Nj、Cu、Pb以及强致酸水溶性阴离子SO4^2-、NO3-、Cl-的浓度均远远高于雨水,说明雾区大气环境的污染程度比降雨天气更高.
Fog water samples during six heavy fog events were collected at Nanjing University of Information Science and Technology (NUIST) from 15 November 2007 to 31 December 2007. Concentrations of five water-soluble anions and fourteen metal elements were detected by ion chromatography and plasma emission spectrometry. The results showed that the pH values ranged from 4.64 to 6.88 among these fog water samples. The average SO4^2- anion concentration (2864.9μmol·L^-1 ) was the highest, followed by Cl- (1584.41μmol·L^-1 ) and NO3- (736.0μmol·L^-1). The average concentration of heavy metal elements Cu, Ni, Pb, Cd and Cr were 2.30, 1.46, 0.42, 0.41 and 0.37 μmol·L^-1respectively while the Ca, K, Na, Mg, AI and Zn concentrations were much higher. The concentration of metal elements in fog water was high at the initial fog stage, then decreased with the fog development, but increased significantly after sunrise during the peak traffic period. Obvious diurnal variation of NO2- was manifested as higher values at night, but very low or undetectable levels after sunrise. The average pH of fog water (6.20) was higher than rain water (4.91), but the conductivity of fog water was 10.5 times higher than that of rain water. The concentration of heavy metal elements ( Cd, Cr, Ni, Cu and Pb) and water-soluble anions (SO4^2-、NO3-、Cl-) in fog water was far higher than rain water. Therefore the air pollution in fog areas was higher than on rainy days.