摘要
运用激光雷达和大气污染监测网络观测了2007年2月北京地区2次平流雾大气污染过程.通过分析雾生消过程中大气颗粒物消光性的垂直结构、地面大气污染物质量浓度的水平分布及其演变,研究了北京市雾日大气污染的空间结构特征.结果表明:雾生成前及持续阶段大气扩散条件较差,污染积累明显,但高湿度雾能加速污染物的湿沉降,雾生成后污染会略有回落.雾生成前后大气污染垂直分布变化显著,但静稳气象条件下,大气污染的水平分布受雾的影响较小.相对湿度是影响雾日大气污染变化的重要因素,决定了污染物湿沉降量的大小.在2007年2月21—22日的平流雾过程中,SO2和NO2浓度与雾生成前相比分别下降了56%与47%,湿沉降量分别为48.0和30.8 g/km2;而在25—27日的平流雾过程中,SO2和NO2湿沉降量分别为16.3和14.3 g/km2.
The spatial structures of atmospheric pollution during two advection fog processes were observed in Beijing in February 2007 using laser radar and an atmospheric pollution monitoring web.The processes were studied by analyzing the vertical structure of light extinction properties of atmospheric aerosol in the course of fog formation and dispersion and analyzing the horizontal distribution and evolution of the concentration of surface atmospheric pollutants.The results were as follows： air diffusive conditions worsened and the accumulation effect of air pollutants became obvious before fog formation.However,the increase of humidity could accelerate the wet deposition rate after the formation of fog,which lessened air pollution.The difference of thermodynamic and dynamical character before and after fog formation can strongly influence pollution vertical distribution,but not the horizontal distribution,which was subject to the transportation convergence around Beijing.Humidity played an important role in atmospheric pollution on the foggy days.Wet depositions（fog scavenging） of SO2 and NO2 were 48.0 and 30.8（g/km2）,respectively,which were reduced by 56% and 47% during the February 21-22 fog event,and 16.3 and 14.3（g/km2）,respectively,during the February 25-27 fog event.
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2009年第9期1032-1038,共7页
Research of Environmental Sciences
基金
中央民族大学"985"工程(CUN985-3-3)
关键词
平流雾
湿度
大气污染
空间分布
advection fog
humidity
atmospheric pollution
spatial distribution
