重庆市荣昌区冬季典型霾期大气颗粒物浓度垂直变化特征

Vertical Variation Characteristics of Atmospheric Particulate Matter Concentration during Typical Haze in Winter in Rongchang District,Chongqing

为探究川东平行岭谷大气颗粒物质量浓度垂直变化特征,通过对四川盆地偏东部的重庆市荣昌区典型雾霾期气象条件下大气颗粒物质量浓度(PM_(1),PM_(2.5)和PM_(10))的垂直连续监测,分析温度、风速、相对湿度等气象条件与大气颗粒物浓度垂直分布的关系。结果表明:PM_(1),PM_(2.5),PM_(10)的日变化在各高度范围内均表现为夜间浓度较高。3种粒径段颗粒物的质量浓度均随高度升高而下降,0~300 m内颗粒物质量浓度最高,PM_(1),PM_(2.5),PM_(10)分别为39.61,193.62,338.87μg/m^(3)。不同空气质量状况下,颗粒物浓度纵向分布不同。空气质量为良时,颗粒物随高度升高缓慢下降,600 m处PM_(1),PM_(2.5)和PM_(10)浓度为100 m处的70.49%,69.60%,65.94%;轻度污染期间,600 m高度的颗粒物浓度比空气质量良时低12.13,59.40,102.03μg/m^(3),PM_(1),PM_(2.5)和PM_(10)地面浓度分别是600 m处的3.54,4.34,4.26倍,颗粒物主要在近地面聚集。颗粒物垂直方向浓度分布受相对湿度的影响最明显,其次是风速和温度。本地及周边地区工业企业排放的污染物以及荣昌区自身地势特点导致颗粒物无法充分扩散使得颗粒物浓度随高度升高快速降低。

To explore the vertical variation characteristics of mass concentration of atmospheric particulate matter(PM)in the parallel ridge valley of east Sichuan,the vertical continuous monitoring for the mass concentration of PM(PM_(1),PM_(2.5)and PM_(10))during typical haze period was conducted in Rongchang District of Chongqing at the eastern part of Sichuan Basin,and the relationship between meteorological conditions(temperature,wind speed and relative humidity)and the vertical distribution of PM concentration was analyzed.The results show that the mass concentrations of PM_(1),PM_(2.5)and PM_(10)within various altitude ranges exhibit higher at night during the day.And the mass concentrations of PM_(1),PM_(2.5)and PM_(10)decrease with height,with the highest mass concentration of particles within 0-300 meters,reaching 39.61,193.62 and 338.87μg/m^(3),respectively.However,the longitudinal distribution of PM is various under different air quality conditions.When the air quality is good,the concentration of PM decreases slowly with height.At an altitude of 600 m,the concentrations of PM_(1),PM_(2.5)and PM_(10)are 70.49%,69.60%and 65.94%of those at 100 m,respectively.During mild pollution period,the concentrations of particulate matter at 600 m are 12.13,59.40,102.03μg/m^(3)lower than those during the period of good air quality,and the ground concentrations of PM_(1),PM_(2.5)and PM_(10)are 3.54,4.34,and 4.26 times higher than those at 600 m,respectively,which means the particulate matter mainly clusters near the ground.The vertical concentration distribution of particulate matter is most affected by relative humidity,followed by wind speed and temperature.Pollutants emitted by industrial enterprises in local and surrounding areas,as well as the terrain characteristics of Rongchang District,lead to insufficient diffusion of particulate matter,resulting in the rapid reduction of particulate matter concentration with the increase of height.