临安夏季霾和清洁天气PM_(2.5)化学组成特征比较  

Comparison of Chemical Components Characteristics of PM_(2.5) Between Haze and Clean Periods During Summertime in Lin'an

作　　者：梁林林 孙俊英[1] 张养梅[1] 刘畅[1] 徐婉筠[1] 张根[1] 刘旭艳 马千里 LIANG Lin-lin;SUN Jun-ying;ZHANG Yang-mei;LIU Chang;XU Wan-yun;ZHANG Gen;LIU Xu-yan;MA Qian-li(State Key Laboratory of Severe Weather ＆ Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing 100081, China;National Satellite Meteorological Center, Beijing 100081, China;Lin＇an Regional Atmosphere Background Station, Lin＇an 311307, China)

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室和大气化学重点开放实验室,北京100081 [2]国家卫星气象中心,北京100081 [3]临安大气本底污染监测站,临安311307

出　　处：《环境科学》2018年第7期3042-3050,共9页Environmental Science

基　　金：中国气象科学研究院基本科研业务费专项(2015Y001;2017Z011);国家自然科学基金项目(41305116;41505107)

摘　　要：本研究对长江三角洲背景地区临安大气本底站夏季PM_(2.5)进行连续采集,并对其分别进行OC/EC和水溶性离子测试分析.研究结果发现,临安夏季PM_(2.5)中OC和EC平均质量浓度分别为(14.3±3.95)μg·m-3和(3.33±1.47)μg·m-3.与城市地区相比,本研究临安背景地区夏季气溶胶中OC和EC相关性较弱(R2=0.31,P<0.01).二次无机离子,即SO_4^(2-)、NO_3^-、NH_4^+(SNA),明显高于其它水溶性无机离子,平均浓度分别为(8.70±5.66)、(2.04±1.07)和(3.25±2.29)μg·m-3.基于对临安夏季PM_(2.5)连续加密观测、气团后向轨迹以及火点图研究分析,发现静稳天气条件和区域传输都可以影响临安地区PM_(2.5)的化学组成特征.此外,通过对临安本底站霾天和清洁天PM_(2.5)化学组成特征比较发现,与清洁天相比,霾污染天气POC和EC占PM_(2.5)的质量分数没有明显变化,而SOC占PM_(2.5)的质量分数却呈现了明显的下降趋势.与SOC不同,SO_4^(2-)和NH_4^+占PM_(2.5)的质量分数在霾污染天气均呈现了上升的趋势,说明二次无机离子有另一种明显增强的化学生成路径,即非均相化学反应.PM2.5 samples were collected at a background site of the Yangtze River Delta in China,during summertime,of which the carbonaceous components,i. e.,OC and EC,and water-soluble inorganic ions,including sulfate,nitrate,and ammonium,were quantified. The average concentrations of OC and EC in PM2.5 during summer at Lin＇an were（ 14. 3 ± 3. 95） μg·m^-3 and（ 3. 33 ±1. 47） μg·m^-3,respectively. Compared to an urban site,the correlation between OC and EC during summertime in Lin＇an,which was a rural site,was relatively weak（ R2= 0. 31,P〈0. 01）. The concentrations of secondary inorganic aerosols（ sulfate as SO4^2-,nitrate as NO-3,and ammonium as NH＋4） were much higher than those of other water-soluble inorganic ions,with average values of（ 8. 70 ±5. 66）,（ 2. 04 ± 1. 07）,and（ 3. 25 ± 2. 29） μg·m^-3,respectively. Based on long-term intensive observations,combined with the analysis of back trajectory and fire spots observations,it was revealed that regional transport and stable synoptic conditions both play important roles in controlling the variations in aerosol chemical components. During the transition from clean to hazy days,the EC and POC fractions showed no obvious variation; in contrast,the SOC fraction decreased obviously. Unlike for SOAs,relative contributions of sulfate and ammonia to PM2.5 increased during hazy days,suggesting enhanced chemical production via other pathways for these two secondary inorganic ions,probably through heterogeneous reactions.

关 键 词：PM2.5 霾 有机气溶胶 水溶性无机离子 临安 

分 类 号：X513[环境科学与工程—环境工程]