| 黑炭气溶胶质谱仪(SP-AMS)分析春季PM2.5中水溶性有机气溶胶 |
| 摘要点击 1862 全文点击 692 投稿时间：2019-07-31 修订日期：2019-09-04 |
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| 中文关键词 细颗粒物(PM2.5) 黑炭-气溶胶质谱(SP-AMS) 正定矩阵因子分解法(PMF) 水溶性有机气溶胶(WSOA) 源解析 |
| 英文关键词 fine particle (PM2.5) soot particle aerosol mass spectrometer (SP-AMS) positive matrix factorization (PMF) water-soluble organic aerosol (WSOA) source apportionment |
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| 中文摘要 |
| 为探讨常州春季大气细颗粒物（PM2.5）的化学组成及污染特征，于2017年3月1日~5月30日采集了84个有效样品，对其水溶性离子（WSIIs）、碳质组分（OC和EC）等常规组分进行了测定和分析，并采用黑炭-气溶胶质谱仪（SP-AMS）对水溶性有机气溶胶（WSOA）进行了分析.结果表明，采样期间PM2.5的日均质量浓度为101.97 μg·m-3，超标（环境空气质量标准二级标准）率达73.8%，以轻度、中度和重度污染为主，分别占总天数的39.3%、21.4%和13.1%.WSIIs约占PM2.5的39.86%，其中二次离子（SO42-、NH4+和NO3-）占WSIIs的81.85%，阴阳离子电荷平衡的线性拟合直线的斜率（AE/CE）大于1（1.09），表明PM2.5偏弱酸性.OC/EC比值为2.53，说明受二次转化的影响.SP-AMS分析WSOA组分包含CxHy+（32.1%）、CxHyO+（30.4%）、CxHyO2+（25.4%）和HyO+（4.7%），其平均氧碳比（O/C）、氢碳比（H/C）、氮碳比（N/C）和有机质-有机碳比（OM/OC）分别为0.72、1.53、0.04和2.15，高的O/C表明春季光化学反应导致的二次转化贡献较大.正定矩阵因子分析模型（PMF）对WSOA的质谱进行解析得到：类烃OA（HOA）、半挥发氧化性-生物质燃烧排放OA（SVOOA-BBOA）和低挥发性氧化性OA（LVOOA）3种有机气溶胶，分别占WSOA总量的18.4%、34.1%和47.4%. |
| 英文摘要 |
| To investigate the chemical composition and pollution characteristics of spring fine particles (PM2.5) in Changzhou, a total of 84 PM2.5 samples were collected from March 1st to May 30th, 2017. We measured and analyzed conventional components, such as water-soluble ions (WSIIs) and carbonaceous components (OC and EC). The water-soluble organic aerosol (WSOA) was also analyzed by an aerodyne soot particle aerosol mass spectrometer (SP-AMS). During the sampling period, the average daily PM2.5 concentration was 101.97 μg·m-3, with more than 73.8% sampling days exceeding the Target-2 standard of the national ambient air quality standard of China. The air quality during the sampling period was dominated by light, moderate, and heavy pollution, accounting for 39.3%, 21.4%, and 13.1% of the total days, respectively. The total WSIIs accounted for 39.86% of PM2.5 mass, of which secondary ions (SO42-, NH4+, and NO3-) accounted for 81.85% of the total WSIIs. The slope of the linear fitted line of the anion and cation charge balance (AE/CE) was greater than 1 (1.09), which indicated that PM2.5 was weakly acidic. The average OC/EC ratio was 2.53, indicating that PM2.5 was influenced by the secondary conversion. WSOA included CxHy+(32.1%), CxHyO+(30.4%), CxHyO2+(25.4%), and HyO+(4.7%) identified by SP-AMS. The average oxygen-to-carbon (O/C), hydrogen-to-carbon (H/C), nitrogen-to-carbon (N/C), and organic matter-to-organic carbon (OM/OC) ratios of the WSOA were 0.72, 1.53, 0.04, and 2.15, respectively. Higher O/C indicated higher contributions from secondary photochemical reaction conversion in spring. Positive matrix factorization (PMF) analysis for AMS mass spectra of WSOA identified three sources, namely hydrocarbon-like (HOA), semi-volatile oxygenated OA (SVOOA)-biomass burning OA (BBOA), and low-volatility oxygenated OA (LVOOA), which on average accounted for 18.4%, 34.1%, and 47.4% of the total WSOA, respectively. |
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