乌鲁木齐大气细颗粒物PM2.5水溶性离子浓度特征及其来源分析

Analysis the Effect and Source on Water-Soluble Ions of Fine Particulate Matter(PM_(2.5)) in Urumqi

大气细颗粒物PM_(2.5)是危害人体健康和环境最主要的空气污染物之一,对其水溶性离子的研究是一项非常必要而迫切的工作。文章对乌鲁木齐市中心区域树木年轮实验室和黑山头2013年1月-2014年2月期间采集的大气细颗粒物样品,利用离子色谱仪分析了其中的水溶性离子分布特征,采用硫转化率(SOR)、离子相关性分析等分析其可能来源,结果表明:年轮室和黑山头PM_(2.5)中总离子浓度平均值分别为88.03和65.11μg·m^(-3),分别占PM_(2.5)质量浓度的51.21%和33.8%。年轮室各种离子的季节变化明显:SO_4^(2-)、NO_3^-、Cl^-和NH_4^+表现为冬季>秋季>春季>夏季,Na^+表现为冬季>秋季>夏季>春季,Ca^(2+)表现为秋季>夏季>春季>冬季。SO_4^(2-)、NO_3^-和NH_4^+是PM_(2.5)中主要的离子,(NH_4)_2SO_4、NH_4HSO_4和NH_4NO_3是乌鲁木齐PM_(2.5)中水溶性组分的可能结合方式。Cl^-和K^+主要来源于化石燃料和生物质的燃烧排放,Ca^(2+)和Mg^(2+)主要来自土壤、二次扬尘和燃煤。乌鲁木齐大气PM_(2.5)中ρ(NO_3^-)/ρ(SO_4^(2-))为0.40,说明目前固定排放源仍然是乌鲁木齐大气污染物的主要来源。本研究为更深入了解乌鲁木齐市颗粒物污染现状提供参考,同时为确定乌鲁木齐市大气污染治理重点、制定大气污染防治规划提供依据。

Based on the data of atmospheric aerosol(PM_(2.5)) form Jan.2013 to Feb.2014 at Meteorological Administration Tree-ring Laboratory(TRL) and Meteorological Satellite Station(MSS) in the center of Urumqi,and water-soluble ions were analyzed by ion chromatogram(IC).Based on the sulfur oxidation ratio(SOR) and the correlation of ions,the possible emission sources were discussed.The results showed that,The total water-soluble ions of PM_(2.5) at TRL and MSS sites were 88.03 μg·m^(-3) and 65.11 μg·m^(-3),and accounted for 81.99%and 86.24%of PM_(2.5) mass concentrations,respectively.Seasonal variations of water-soluble ions were:SO_4^(2-),NO_3^-,Cl^- and NH_4^+ showed winter > autumn> spring > summer;Na^+ showed winter > autumn > summer > spring;Ca^(2+)showed autumn > summer > spring > winter.SO_4^(2-),NO_3^- and NH_4^+ were the major species in water-soluble ions,and they were mainly in the form of(NH_4)_2SO_4、NH_4HSO_4 and NH_4NO_3 in PM_(2.5).Cl^- and K^+ were mainly from the burning of fossil fuels and emissions of biomass;Ca^(2+) and Mg^(2+) were mainly from soil,secondary dust and burning of coal.NO_3^- and SO_4^(2-) concentration ratio was 0.40,and it showed that stationary source emissions were still the main pollution in Urumqi.Based on the data of atmospheric aerosol(PM2.5) form Jan. 2013 to Feb. 2014 at Meteorological Administration Tree-ring Laboratory(TRL) and Meteorological Satellite Station(MSS) in the center of Urumqi, and water-soluble ions were analyzed by ion chromatogram(IC). Based on the sulfur oxidation ratio(SOR) and the correlation of ions, the possible emission sources were discussed. The results showed that, The total water-soluble ions of PM2.5 at TRL and MSS sites were 88.03 μg·m^(-3) and 65.11μg·m^(-3), and accounted for 81.99% and 86.24% of PM2.5 mass concentrations, respectively. Seasonal variations of water-soluble ions were: SO_4^(2-), NO_3^-, Cl^- and NH_4^+ showed winter > autumn> spring > summer; Na+ showed winter > autumn > summer > spring; Ca^(2+) showed autumn > summer > spring > winter. SO_4^(2-), NO_3^- and NH_4^+ were the major species in water-soluble ions, and they were mainly in the form of(NH4)2SO4、NH4HSO4 and NH4NO3 in PM2.5. Cl- and K+ were mainly from the burning of fossil fuels and emissions of biomass; Ca^(2+) and Mg^(2+) were mainly from soil, secondary dust and burning of coal. NO_3^- and SO_4^(2-) concentration ratio was 0.40, and it showed that stationary source emissions were still the main pollution in Urumqi.