昆明市臭氧污染特征及气象条件影响分析

Analysis of ozone pollution characteristics and meteorological conditions in Kunming

利用2014—2019年昆明市臭氧(O_(3))监测数据及气象资料,分析昆明市O_(3)污染特征及气象条件对其的影响,归纳总结了昆明地区出现O_(3)污染的天气形势、污染物的水平和垂直外源输送情况.结果表明:(1)O_(3)浓度逐年增加,污染主要发生于春、夏季,O_(3)与温度、风速呈显著正相关,与相对湿度呈负相关;(2)昆明地区出现O_(3)污染时主要有5种天气类型,其中以低槽东移型、两高辐合型、东风波型出现的频次较多;在天气系统的作用下,利于将上游区域的高浓度O_(3)向昆明上空水平输送,HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory)后向轨迹也进一步验证,气团的移动路径与污染物浓度及天气系统配合较好;(3)垂直方向上,污染过程发生前1~2 d,平流层下层高浓度O_(3)向对流层及近地层垂直输送明显.在有利的气象条件下,加之O_(3)的水平和垂直外源输送,利于污染物的积累和生成,最终造成昆明地区O_(3)质量浓度超标.

Based on the ozone monitoring data and meteorological data from 2014 to 2019 in Kunming,the characteristics of ozone pollution and the influence of meteorological conditions on ozone pollution were analyzed;meanwhile,the weather situation,and the horizontal and vertical external transports of ozone pollutants were generalized and summed up in Kunming.The results showed that:Firstly,O_(3)concentration was increasing year by year,and pollution mainly occurred in spring and summer.Ozone was significantly positively correlated with temperature and wind speed,and negatively correlated with relative humidity.Secondly,the ozone pollution events of Kunming were classified into five synoptic types,among which the most frequent were low trough eastward-moving type,two-high-convergence type and easterly wave type.The effect of weather systems was conducive to the horizontal transportation of high concentration O_(3)from upstream regions to Kunming.Hybrid Single Particle Lagrangian Integrated Trajectory(HYSPLIT)backward trajectory further verified that the air mass movement path was consistent with the pollutant concentration and weather system.Lastly,in the vertical direction,1−2 days before the pollution process occurred,the high concentration O_(3)air in the lower stratosphere was transported vertically to the troposphere and the near ground.Therefore,favorable meteorological conditions,combined with the horizontal and vertical external transports of O_(3),were conducive to the accumulation and generation of pollutants,hence resulting in O_(3)exceeding the standard in Kunming.