嘉兴市春季一次持续雾霾过程中气象条件与污染物变化特征分析  

Observation Analysis on the Characteristics of Meteorological Elements and Pollutants During a Continuous Fog and Haze Episode in Spring in Jiaxing City

作　　者：沈利娟[1,2] 王红磊[3] 李莉[2] 吕升[2] 袁婧[2] 张孝寒 章国骏 王翡[2] 

机构地区：[1]南京信息工程大学环境科学与工程学院,江苏省大气环境监测与污染控制高技术研究重点实验室,南京210044 [2]嘉兴市环境保护监测站,嘉兴314000 [3]南京信息工程大学气象灾害教育部重点实验室,气候与环境变化国际合作联合实验室,气象灾害预报预警与评估协同创新中心,中国气象局气溶胶与云降水重点开放实验室,南京210044

出　　处：《环境科学》2016年第8期2871-2880,共10页Environmental Science

基　　金：江苏省大气环境监测与污染控制高技术研究重点实验室开放基金项目(KHK1408);嘉兴市大气细颗粒物(PM2.5)来源解析及控制技术研究项目(2014AY21012);中国科学院战略性先导科技专项(B类)(XDB05020206);国家自然科学基金项目(41275143;41305135);江苏高校优势学科建设工程资助项目(PAPD)

摘　　要：2015年5月17~20日嘉兴市发生了一次持续性雾霾过程,本研究根据5月17~22日污染气体(O_3、SO_2、NO_2和CO)、PM_(10)、PM_(2.5)、10 nm^10μm气溶胶数浓度、气象要素及边界层探空数据,分析了这次过程的成因及其不同污染物的变化特征.结果表明,副高位置北抬、均压场结构、地面静小风和边界层中逆温层为这次雾霾过程的发生和维持提供了水汽、动力和热力条件.这次雾霾过程包含1次降雨和2次雾过程(雨雾和辐射-平流雾).雾霾过程中NO_2、CO、PM_(10)和PM_(2.5)的浓度较高,SO_2和O_3的浓度较低.强降雨对PM_(10)、PM_(2.5)和SO_2清除作用较大,弱降雨会加重污染过程.雨雾的发展过程中,PM的浓度持续积聚;辐射-平流雾过程中,PM浓度先快速下降然后再增加.不同过程中气溶胶数浓度谱均为单峰型分布,但是谱型差异较大,干净天、降雨、雾霾过程、雨雾和辐射-平流雾过程中气溶胶数浓度谱峰值分别位于20~30 nm、100 nm、30~60nm、120 nm和90 nm.表面积浓度谱在干净天、降雨、雾霾和雨雾过程中均为三峰型分布,辐射-平流雾为四峰型分布.A continuous fog and haze episode occurred on 17-20 May,2015 in Jiaxing. Trace gases（ O3,CO,SO2 and NO2,PM10,PM2.5）,aerosol number concentration in the range of 10 nm-10 μm,meteorological elements,and radiosonde data from the 17 st to the22 st of May were used to analyze the formation mechanism and pollutant characteristics during this episode. The results showed that subtropical high pressure lifted northward,a field pressure was dominant over Jiaxing leading to a weak ground wind speed,and a strong inversion layer occurred,this supplied moisture,power and thermal conditions for the occurrence and maintenance of the event.The episode included one precipitation process and two fog processes（ rainy fog and radiation-advection fog）. During the fog and haze process,the concentrations of NO2,CO,PM10 and PM2.5were high and the levels of SO2 and O3 were low. Strong precipitation had greater scavenge effects on PM（10）,PM2.5and SO2,while weak precipitation aggravated the pollution degree. The PM concentrations increased continuously during the rainy fog process,while it decreased firstly and then increased during the radiation-advection fog process. The spectral distributions of aerosol number concentration were unimodal and differed significantly under different types of weather conditions. The peaks of number concentration were located at 20-30 nm,100 nm,30-60 nm,120 nm,90 nm under clean,precipitation,fog and haze,rainy fog,radiation-advection fog conditions,respectively. The spectra of surface area concentration were trimodal under clean,precipitation,fog and haze,rainy fog conditions,and had four peaks under radiation-advection fog condition.

关 键 词：气溶胶 雾霾 PM2.5 粒径分布 污染气体 

分 类 号：X511[环境科学与工程—环境工程]