南京北郊冬季大气S0_2、N0_2和0_3的变化特征

利用差分吸收光谱仪DOAS(differential optical absorption spectroscopy),对2007年11月-2008年1月南京北郊大气SO_2、NO_2和O_3进行了观测.结合Parsivel降水粒子谱仪和自动气象站的资料,对冬季大气污染气体的浓度变化规律及降水和风速风向对其的影响进行了分析.结果表明,南京北郊大气SO_2浓度较高,呈明显双峰特征,分别在12时(北京时,下同)和00时达最大,受附近排放源的影响最大,东风及南风时比静风时SO_2浓度更高.降水对SO_2湿清除效果明显,清除系数平均为0.168h~(-1).NO_2气体呈明显单峰特征,在18时达最高值.南京北郊是NO_2源区之一,主要受附近高速公路汽车尾气排放源的影响.静风时NO_2浓度最高.O_3浓度受NO_2的影响较明显.O_3日变化呈单峰特征,在15时达最大值,静风时O_3浓度最低.降水对O_3的间接影响较明显,在降水时,白天由于太阳辐射较弱,O_3浓度降低;夜晚NO浓度较低,使得O_3浓度升高.

Characteristics of S0_2,NO_2 and O_3 over North Suburb of Nanjing in Winter

Based on the differential optical absorption spectroscopy(DOAS)technology,SO_2,NO_2 and O_3 of the north suburban area of Nanjing from November 2007 to January 2008 were measured.By u-sing the data of Parsivel Disdrometer and automatic weather station,the characteristics of atmospheric pollutant concentrations and the effects of precipitation and wind speed and direction on the concentra-tions were analyzed.The results indicate that the concentration of SO_2 in the north suburban area of Nanjing was high and peaked at 1200 and 0000 BST.SO_2 was mostly influenced by the emission source around the measurement site;and the concentration was higher when the wind direction Was east and south than calm wind.The wet scavenging effect of precipitation on SO_2 was significant and the wet scavenging coefficient was averaged 0.168 h~(-1).The concentration of NO_2 was characteristic of single peak and peaked at 1800 BST.The north suburban site of Nanjing is nearby one of the NO_2 emission sources and largely influenced by the vehicle emission from a highway.The concentration of NO_2 was highest when the wind was calm.O_3 was influenced by NO_2 greatly and its concentration was characmr-istic of the single peak at 1500 BST;it had the lowest concentration when the calm wind condition occurred. Precipitation had greatly impact on O_3;and the O_3 concentration was lower in daytime for less solar radiation and higher in night for lower NO concentration.