沈阳地区一次重污染沙尘天气过程成因分析

Analysis of the Causes of a Heavy Polluted Sand and Dust Weather Process in Shenyang Area

以2023年4月11~14日沈阳地区一次重污染沙尘天气为例,利用常规污染物监测数据、气象数据、激光雷达数据及在线源解析数据,从气象条件和污染源传输等方面分析了此次污染过程的成因。结果表明:集中在近地面800 m以下,受弱冷空气南下影响,气团所携带污染物传输至沈阳地区造成可吸入颗粒物浓度迅速增加,随着高空冷空气减弱,PM_(10)浓度有所下降,午后转为西南风导致沙尘回流,可吸入颗粒物浓度加速升高并持续,而西南方向暖湿气流使沈阳地区湿度增加,空气中的大量水汽包裹颗粒物下沉,造成颗粒物吸湿增长,污染加剧。监测数据结果显示,此次污染主要受浮尘和扬沙影响较大。

Taking a heavily polluted sandstorm weather in Shenyang area from April 11-14,2023 as an example,conventional pollutant monitoring data,meteorological data,LiDAR data,and online source analysis data are used.The causes of this pollution process were analyzed from the perspectives of meteorological conditions and pollution source transmission.The results indicate that the concentration of pollutants carried by the air mass was below 800m near the ground,and due to the influence of weak cold air moving south,the concentration of inhalable particulate matter was transferred to Shenyang,which resulted in a rapid increase in the concentration of inhalable particulate matter.As the cold air at high altitude weakens,the concentration of PM_(10)decreases,and in the afternoon,it shifts to a southwest wind,causing sand and dust to flow back.The concentration of inhalable particulate matter accelerates and continues to rise.The warm and humid air flow in the southwest direction increases humidity in the Shenyang area,causing a large amount of water vapor in the air to envelop particles and sink,resulting in an increase in particle moisture absorption and intensified pollution.The monitoring data results show that the pollution is mainly affected by floating dust and blowing sand.