南京地区大气颗粒物影响近地面臭氧的个例研究

通过对2008年4月2～7日南京地区地面气象观测数据以及两个站点空气质量(O₃、NO_x、PM10)监测资料的分析, 发现O₃和PM10之间存在一定程度的反相关。利用一个光化学箱模式对该个例中大气颗粒物影响近地面臭氧的过程进行模拟, 结果发现大气颗粒物浓度的升高使得气溶胶光学厚度增加20％～40%, 导致NO₂和O₃近地面光解率下降20%～30%, OH和HO₂自由基浓度分别减少20%～50%, 造成O₃净生成率下降30%～40%。研究表明, 颗粒物对光化学过程的抑制造成了大气氧化能力的降低, 是近地面臭氧浓度减少的可能原因。

Impacts of Atmospheric Particles on Surface Ozone in Nanjing

By analyzing surface meteorological observations and air quality monitoring data (O₃, NO_x, and PM10) at two stations from 2 April to 7 April 2008, in Nanjing, eastern China, the inverse correlation between O₃ and particulate matter is determined. A photochemical box model is employed to interpret the possible mechanism. The simulation shows that elevated concentration of particulate matter can increase the aerosol optical depth by 20%-40% and reduce averaged photolysis rates of NO₂ and O₃ and concentration of OH and HO₂ by 20%-30% and 20%-50%, respectively, which leads to a 30%-40% decrease in the net photochemical production rate of O₃. The results indicate that the effects of atmospheric particles on photochemistry and the oxidation ability of the atmosphere are responsible for the reduction of the observed surface O₃ concentration.