Concentrations and chemical compositions of fine particles (PM2.5) during haze and non-haze days in Beijing
Concentrations and chemical compositions of fine particles (PM2.5) during haze and non-haze days in Beijing
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北京雾霾天和非雾霾天细颗粒物（PM2.5）浓度及化学成分
DOI：
10.1016/j.atmosres.2016.02.003
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发表时间：
2016-06-15
影响因子：
5.5
通讯作者：
Zhang, Yuanxun
中科院分区：
文献类型：
--
作者：
Zhang, Yang;Huang, Wei;Zhang, Yuanxun
为研究PM2. 5的化学特性，提出合理的控制措施，于2012年8月4日至9月3日在北京市某城区采集了PM2. 5的日采样数据。对8种水溶性无机离子（WSII，包括Na+、NH 4+、K+、Mg 2+、Ca 2+、Cl-和SO 4-）、有机碳（OC）和元素碳（EC）进行了化学分析。PM2.5的浓度介乎8.8至218.6 μ g m（-3），平均浓度为80.6 +/- 573 μ g m（-3）。WSII是PM2.5最主要的成分，占其质量的60 +/- 18%，浓度介乎3.1至172.2 μ m m（-3）。SO 42-、NO3-和NH 4+占WSII的90 +/- 28%，其浓度分别为1.3-105.7 μ g m（-3）、0.5-52.7 μ g m（-3）和0.3-33.5 μ g m（-3）。OC和EC的浓度分别为3.0-28.8 μ gCm（-3）和0.8-7.4 μ gCm（-3），分别占PM2.5的17.6%和4.9%。活动期间发生了三次严重污染事件（雾霾天）。PM2.5及其化学物质在雾霾期间大幅增加。灰霾天气中SO 42-（4.5）、NO3-（4.0）和NH 4+（4.2）的增强因子均大于非灰霾天气，说明这些二次无机离子在灰霾的形成中起着重要作用。NO3-/SO 42-的平均比值为0.52。离子平衡计算表明，PM2.5样品在雾霾期间呈酸性，在非雾霾天接近中性。对主要离子进行了相关性分析，结果表明，NH 4+的主要存在形式为（NH 4）（2）SO 4。此外，还讨论了灰霾日与非灰霾日OC、EC及OC/EC比值的变化规律。(C)© 2016 Elsevier B. V.版权所有。
To investigate the chemical properties of PM2.5 and put forward reasonable control measures, daily samples of PM2.5 were collected at an urban site in Beijing from August 4 to September 3 of 2012 using two 2-channel samplers. Chemical analysis was conducted for eight water soluble inorganic ions (WSII, including Na+, NH4+, K+, Mg2+, Ca2+, Cl-, and SO4-), organic carbon (OC) and elementary carbon (EC). PM2.5 concentrations ranged from 8.8 to 218.6 mu g m(-3), with an average concentration of 80.6 +/- 573 mu g m(-3).WSII, the most dominant PM2.5 constituents contributing 60 +/- 18% of its mass, ranged from 3.1 to 172.2 mu m m(-3). SO42-, NO3-, and NH4+ dominated WSII (90 +/- 28%) and their concentrations were 1.3-105.7 mu g m(-3), 0.5-52.7 mu g m(-3) and 0.3-33.5 mu g m(-3), respectively. The concentrations of OC and EC were 3.0-28.8 mu gC m(-3) and 0.8-7.4 mu gC m(-3) constituting 17.6% and 4.9% of PM2.5, respectively. Three serious pollution episodes (haze days) occurred during the campaign. PM2.5 and its chemical species showed substantial increases during haze episodes. The greater enhancement factors for SO42- (4.5), NO3- (4.0), and NH4+ (4.2) during haze days compared to non-haze days were obtained, suggesting that these secondary inorganic ions play important roles in the formation of haze. The average ratio of NO3-/SO42- was 0.52. Ion balance calculations showed that PM2.5 samples were acidic during haze periods and close to neutral during non-haze days. Correlation analysis between the major ions was conducted and the results suggested that the main forms of NH4+ might be (NH4)(2)SO4. In addition, the variations between haze days and non-haze days for OC, EC, and the ratio of OC/EC were discussed. (C) 2016 Elsevier B.V. All rights reserved.