摘要
为研究本溪市大气PM_(2.5)中水溶性离子污染特征,于2016年1—10月在本溪市开展PM_(2.5)样品采集,使用离子色谱法分析了其中8种水溶性离子(Cl^-、NO_3^-、SO_4^(2-)、NH_4^+、Ca^(2+)、Na^+、Mg^(2+)、K^+),并采用PMF(positive matrix factorization,正矩阵因子分解法)模型对水溶性离子的来源进行分析.结果表明:观测期间,本溪市ρ(PM_(2.5))平均值为(57.6±21.9)μg/m^3,ρ(PM_(2.5))季节性变化特征明显,呈冬季>秋季>春季>夏季趋势;水溶性离子平均质量浓度为19.3μg/m^3,占ρ(PM_(2.5))的33.6%,各离子质量浓度高低顺序为SO_4^(2-)>NO_3^->NH_4^+>Cl^->Ca^(2+)>K^+>Na^+>Mg^(2+);SNA(SO_4^(2-)、NO_3^-和NH_4^+)是PM_(2.5)中主要的3种离子,在春季、夏季、秋季和冬季分别占水溶性离子的73.2%、88.2%、82.5%和73.6%,表明夏季的二次污染较为严重.阴、阳离子电荷平衡分析结果显示,阴离子相对亏损,本溪市PM_(2.5)整体呈弱碱性,NO_3^-、SO_4^(2-)与NH_4^+相关性较高,其在PM_(2.5)中主要以NH_4NO_3和NH_4HSO_4的形式存在.PMF分析结果表明,本溪市PM_(2.5)中水溶性离子的来源主要包括二次转化源、燃煤源和扬尘源.研究显示,本溪市PM_(2.5)中水溶性离子季节性变化特征明显,二次转化源、燃煤源和扬尘源是其主要来源.
PM 2.5 samples were collected in Benxi City from January to October, 2016, and the water-soluble ions Cl^-, NO3^-, SO4 ^2-, NH4 ^+, Ca2^+, Na^+, Mg2^+ and K^+ in the PM 2.5 were determined by ion chromatography. The results showed during sample collection period ρ(PM 2.5 ) was (57.56±21.9)μg m^3, and the seasonal variations of ρ(PM 2.5 ) were obviously in the order of winter>autumn>spring>summer. The average water-soluble ion concentration was 19.3 μg m^3, which accounted for 33.6% of ρ(PM 2.5 ). The ion concentration was in the order of SO4 ^2->NO3^->NH4 ^+> Cl^->Ca 2^+> K ^+>Na ^+>Mg 2^+. SO 4 ^2-, NO 3^- and NH 4 ^+(SNA) were the main ions in PM 2.5 , accounting for 73.2%, 88.2%, 82.5% and 73.6% of the water-soluble ions in spring, summer, autumn and winter, respectively, and showed that the secondary pollution in summer was more serious. The anion-to-cation ratio in each of the four seasons was less than one, which indicated that PM 2. 5 in Benxi City was slightly alkaline. NO 3^-, SO 4 ^2- and NH 4 ^+ were highly correlated, and they were primarily in NH 4NO3 and NH 4HSO4 forms in PM 2.5 . PMF analysis revealed that secondary transformation, coal burning and dust were the main potential sources of the ionic components of PM 2.5 in Benxi City. In conclusion, results showed that the seasonal variation was obvious of water-soluble ions in PM 2.5 in Benxi City, and secondary transformation, coal burning and dust were the main sources.
作者
张敬巧
王涵
胡君
张萌
柴发合
段菁春
王淑兰
ZHANG Jingqiao;WANG Han;HU Jun;ZHANG Meng;CHAI Fahe;DUAN Jingchun;WANG Shulan(Chinese Research Academy of Environmental Sciences, Beijing 100012, China;China Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China)
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2019年第2期246-252,共7页
Research of Environmental Sciences
基金
国家科技支撑计划项目(No.2014BAC23B05)~~
