西安新颗粒物生成事件与PM_(2.5)污染形成关系  

Relationship Between New Particle Formation Events and PM_(2.5) Pollution in Xi’an

作　　者：赵奎锋[1,3] 彭艳 ZHAO Kuifeng;PENG Yan(Shaanxi Meteorological Observatory,Xi’an 710014,China;Meteorological Institute of Shaanxi Province,Xi’an 710016,China;Key Laboratory of Eco-Environment and Meteorology for The Qinling Mountains and Loess Plateau,Shaanxi Meteorological Bureau,Xi’an 710014,China)

机构地区：[1]陕西省气象台,陕西西安710014 [2]陕西省气象科学研究所,陕西西安710016 [3]秦岭和黄土高原生态环境气象重点实验室,陕西西安710014

出　　处：《干旱气象》2021年第4期593-602,共10页Journal of Arid Meteorology

基　　金：陕西省自然科学基础研究计划“西安地区不同污染天气条件下大气颗粒物分布特征及污染成因研究”(2018JM4024);陕西省重点研发计划“关中地区霾气象条件指数的构建及其在气象服务中的应用”(2019SF-269);秦岭和黄土高原生态环境气象重点实验室面上课题“西安地区秋冬季节大气颗粒物粒径演变特征及气象条件对污染生消的影响”(2019M-9)共同资助。

摘　　要：利用中国气象局秦岭气溶胶与云微物理野外科学试验基地扫描电迁移率粒径谱仪(SMPS,scanning mobility particle sizer,Model 3034)观测的2017年11月1—30日颗粒物粒径谱数据,给出西安9次新颗粒物生成(new particle formation,NPF)事件的统计特征,并结合3次PM_(2.5)污染过程,讨论NPF事件与西安PM_(2.5)污染的可能关系。结果表明:(1)NPF事件一般发生在中午到下午,新颗粒物生成后峰值粒径增长速率平均值为5.1±1.8 nm·h^(-1),凝结核模态颗粒物数浓度的最大净增长量(net maximum increase in nucleation mode particles number concentration,NMINP)平均值为0.63×10^(4)cm^(-3),NPF事件不仅增加了大气中凝结核模态颗粒物数浓度,还增加了爱根核模态和积聚模态颗粒物数浓度;NPF事件有67%存在粒径的持续增长,其中3次事件峰值粒径增长最为显著,最大值增长至175 nm附近。(2)NPF事件发生后,大气中PM_(2.5)质量浓度随颗粒物峰值粒径增大呈增高趋势。(3)3次NPF事件到PM_(2.5)污染过程中PM_(2.5)质量浓度与峰值粒径、积聚模态颗粒物数浓度和凝结汇均呈现指数正相关关系,当峰值粒径为100~120 nm时,PM_(2.5)质量浓度高于75μg·m^(-3),积聚模态颗粒物数浓度持续高于其他两个模态颗粒物数浓度,出现PM_(2.5)污染。Based on the particle size distribution data measured by scanning mobility particle sizer model 3034(SMPS-3034)from the field experiment station of aerosol and cloud microphysics for Qinling moutains,China Meteorological Administration during November 1-30 of 2017,the statistics characteristics of nine new particle formation(NPF)events were analyzed in Xi’an and the relationship between NPF and PM_(2.5)pollution was also discussed combining with three PM_(2.5)pollution cases.The results are as follows:(1)The NPF events started at noon or in the afternoon.The average value of growth rate of the mode particle diameter after NPF and net maximum increase in nucleation mode particles number concentration(NMINP)was 5.1±1.8 nm·h^(-1)and 0.63×10^(4)cm^(-3),respectively.The NPF events contributed not only to the increase of nucleation mode particles number concentration,but also to the increase of Aitken mode and accumulation mode particles number concentrations.The 67 percent of the NPF events had a continuous growth in particle size,three of them had significant increasing in the mode particle diameter,the maximum value of which could reach to 175 nm.(2)There was an obvious increase of PM_(2.5)mass concentration with the growth of the mode particle diameter of the particles after NPF events.(3)The increase of PM_(2.5)mass concentration was positively correlated with the increase of mode particle diameter of the particles,the number concentrations of accumulation mode particles and the condensation sink during three processes from the NPF events to the PM_(2.5)pollution.When the mode particle diameter of the particles increased to 100-120 nm,the number concentration of accumulation mode particles continued higher than that of other two modes,the PM_(2.5)mass concentration was higher than 75μg·m^(-3),and the PM_(2.5)pollution occurred.

关 键 词：NPF事件 PM_(2.5)污染 峰值粒径 积聚模态颗粒物数浓度 凝结汇 

分 类 号：P481[天文地球—大气科学及气象学]