| 太原市冬季不同污染程度下PM2.5的化学组成、消光特征及氧化潜势 |
| 摘要点击 2232 全文点击 697 投稿时间：2021-08-27 修订日期：2021-10-15 |
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| 中文关键词 PM2.5 重污染 消光特征 氧化潜势 太原 |
| 英文关键词 PM2.5 heavy pollution extinction effect oxidative potential Taiyuan |
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| 中文摘要 |
| 为深入探究重污染地区气溶胶的消光特征和健康风险，于2019年冬季开展了太原市PM2.5主要化学成分和氧化潜势的分析.采样期间ρ（PM2.5）为（89.9±33.6）μg ·m-3，其中水溶性离子和碳质气溶胶分别占到43.3%和33.8%，浓度较高的组分依次为：OC>SO42->NO3->EC>NH4+>Cl->Ca2+.随着污染程度的增加，PM2.5中有机物（OM）和矿物尘的占比下降了5.8%和11.2%，而SNA （NO3-、SO42-和NH4+）的质量分数由33.9%显著增加到56.0%.基于IMPROVE公式估算，太原市冬季大气颗粒物的平均消光系数为（453.4±230.0） Mm-1，在清洁天和轻度污染时OM和元素碳（EC）在消光中起主要作用，二者的总贡献率约占55%；而到重度污染时，SNA的贡献率显著上升至70%左右，成为影响大气能见度的主要成分.氧化潜势DTTv的平均值为（2.0±0.9） nmol ·（min ·m3）-1，呈现出随着污染加剧而逐步上升的规律，重度污染下的DTTv是清洁天的2.9倍.从来源上看，二次源（31.7%）及燃煤和生物质燃烧源（26.0%）是太原市冬季PM2.5的主要来源，其次为机动车源（18.1%）、扬尘源（18.0%）和工业源（6.3%）.对比两次重污染事件发现，交通管制对于降低一次源排放的效果明显，而二次源产生的颗粒物其氧化潜势水平可能更高. |
| 英文摘要 |
| In order to deeply explore the extinction characteristics and health risks of aerosols in heavy pollution areas, the main chemical components and oxidative potential of PM2.5 in Taiyuan were analyzed in the winter of 2019. The mass concentration of PM2.5 was (89.9±33.6) μg·m-3 during the sampling period, in which water-soluble ions and carbonaceous aerosol accounted for 43.3% and 33.8%, respectively. The major components of PM2.5 were as follows:OC>SO42->NO3->EC>NH4+>Cl->Ca2+. With the aggravation of pollution, the proportion of organic matter and mineral dust in PM2.5 decreased by 5.8% and 11.2%, respectively, whereas the proportion of secondary inorganic ions-SNA increased from 33.9% to 56.0%. The extinction coefficient of atmospheric particulate matter in Taiyuan in winter calculated by the IMPROVE formula was (453.4±230.0) Mm-1. On the clean and light pollution days, OM and EC played a major role in the light extinction, accounting for approximately 55% of the total contribution, whereas the contribution of SNA increased to approximately 70% with the evolution into heavy pollution and became the main component affecting atmospheric visibility. The mean value of DTTv was (2.0±0.9) nmol·(min·m3)-1, and it showed an increasing trend with the aggravation of haze pollution. The DTTv under heavy pollution was 2.9 times that on clean days. The main sources were secondary sources (31.7%) and coal and biomass combustion sources (26.0%), followed by vehicle sources (18.1%), dust sources (18.0%), and industrial sources (6.3%). Comparing two heavy pollution events, it was found that traffic control had an obvious effect on reducing primary emissions, and the secondary sources may contribute to a higher DTT activity than other sources. |
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