杭州秋冬季PM_(2.5)污染特征分析  

Analysis of Pollution Characteristics of PM_(2.5) in Hangzhou in Autumn and Winter

作　　者：严仁嫦 林旭[1] 金嘉佳[1] 许凯儿 叶辉[1] 何曦[1] 沈建东[1] 何纪平[1] 张海洋[1] YAN Renchang;LIN Xu;JIN Jiajia;XU Kaier;YE Hui;HE Xi;SHEN Jiandong;HE Jiping;ZHANG Haiyang(Hangzhou Environmental Monitoring Central Station,Hangzhou 310012,China)

机构地区：[1]杭州市环境监测中心站,浙江杭州310012

出　　处：《中国环境监测》2021年第6期101-110,共10页Environmental Monitoring in China

基　　金：杭州市农业科研自主申报项目(20170533B15)。

摘　　要：为研究杭州PM_(2.5)污染来源特征,利用2013—2019年杭州市PM_(2.5)监测数据和气象观测数据,分析了杭州市2013—2019年PM_(2.5)浓度变化,选取本地积累型和输入型2种PM_(2.5)污染过程,结合单颗粒气溶胶飞行时间质谱仪(SPAMS)和在线离子色谱数据,探讨杭州市PM_(2.5)化学组分和污染来源。结果表明:每年秋冬季(11月至次年3月)杭州以东北风、西北风及偏南风为主,风速低于4 m/s时,大气扩散条件差,受本地污染物积累影响,PM_(2.5)浓度容易出现超标;风速较大且为东北风和西北风时,受上游污染输入影响,易出现PM_(2.5)重度污染。本地积累型和输入型案例中,PM_(2.5)化学组分中占比最大的为NO^(-)_(3)、SO^(2-)_(4)和NH+4;PM_(2.5)浓度上升过程中,二次NO^(-)_(3)和SO^(2-)_(4)转换率明显上升,其中NO^(-)_(3)上升更为显著,二次气溶胶污染严重。2次案例中,PM_(2.5)来源贡献占比前3位均为机动车尾气源、燃煤源和工业工艺源,其中本地积累型PM_(2.5)浓度上升阶段,机动车尾气源占比会明显上升;输入型案例中,输入阶段机动车尾气源占比显著上升,燃煤源贡献也小幅上升。To investigate the pollution characteristics and sources apportionment of PM_(2.5) in Hangzhou,the national environmental monitoring PM_(2.5) data and meteorological data of Hangzhou during 2013-2019 were used to analyze the changes characteristics of PM_(2.5) concentration in the past five years.And two typical PM_(2.5) pollution processes,local origin and external input,were collected and analyzed for PM_(2.5) chemical composition and pollution source by use a single particle aerosol mass spectrometer(SPAMS)and ion chromatography analyzer data.The results showed that high PM_(2.5) episodes usually occurred in autumn and winter,during the period from November to the following March,because of the pollutants accumulation when the wind speed was lower than 4 m/s.If the wind speed was large and the wind direction was northeast or northwest,it was also prone to occur PM_(2.5) heavy pollution due to pollutants transportation.In both of local accumulation and import cases,the largest proportions of PM_(2.5) chemical components were NO^(-)_(3),SO^(2-)_(4) and NH+4.And the conversion rate of secondary NO^(-)_(3) and SO^(2-)_(4) increased significantly during the increase of PM_(2.5) concentration.The increase of NO^(-)_(3) was more remarkable,and the secondary aerosol pollution was serious in Hangzhou.The source characteristics of PM_(2.5) indicated that the top three pollution sources contributed by PM_(2.5) in Hangzhou were vehicle exhaust,coal combustion and industrial process respectively.In the local accumulation case,the proportion of motor vehicle exhaust increased significantly when the PM_(2.5) concentration rose;and in the imported case,the proportion of motor vehicle exhaust increased significantly,and the contribution of coal-fired sources also increased slightly.

关 键 词：PM_(2.5) 污染过程 污染特征 化学组分 污染来源 

分 类 号：X823[环境科学与工程—环境工程]