Organic molecular compositions and size distributions of chinese summer and autumn aerosols from nanjing: characteristic haze event caused by wheat straw burning.
Organic molecular compositions and size distributions of chinese summer and autumn aerosols from nanjing: characteristic haze event caused by wheat straw burning.
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DOI：
10.1021/es803086g
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发表时间：
2009-08
影响因子：
11.4
通讯作者：
Gehui Wang;K. Kawamura;M. Xie;Shuyuan Hu;Junji Cao;Z. An;J. Waston;J. Chow
中科院分区：
文献类型：
--
作者：
Gehui Wang;K. Kawamura;M. Xie;Shuyuan Hu;Junji Cao;Z. An;J. Waston;J. Chow
在2007年夏秋季节，包括6月1日至5日的一段雾霾天，在中国南京市区收集了不同大小的气溶胶样品。在灰霾事件中的有机气溶胶的特点是左旋葡聚糖，高分子量（HMW）正构烷烃，高分子量脂肪酸的浓度升高，由于现场燃烧的小麦秸秆的排放。相比之下，有机气溶胶在nonhazy天的特点是占主导地位的化石燃料燃烧产物。灰霾样品中左旋葡聚糖（4030 ng m（-3））、正构烷烃（1520 ng m（-3））、脂肪酸（2629 ng m（-3））和多环芳烃（57 ng m（-3））的含量是非事件样品的3-40倍。灰霾期有机物的30-90%可归因于秸秆焚烧。颗粒物（PM）质量，正构烷烃和低分子量（LMW）多环芳烃的浓度呈单峰分布，在有雾的日子里，峰值在0.7-1.1微米，和双峰分布，在非有雾的日子里，峰值在0.7-1.1微米和4.7-5.8微米。有机气溶胶的几何平均直径（GMDs）在霾天的精细模式下（<2.1 microm）较大，表明秸秆燃烧排放的气溶胶比化石燃料燃烧排放的气溶胶大，并且细颗粒物的凝聚和有机化合物的再分配增强。
Size-segregated aerosol samples were collected in urban Nanjing, China during summer and autumn of 2007 including a period of hazy days during June 1-5. Organic aerosols in the haze event were characterized by elevated concentrations of levoglucosan, high molecular weight (HMW) n-alkanes, and HMW fatty acids due to the emissions from field burning of wheat straw. In contrast, organic aerosols on nonhazy days were characterized by a predominance of fossil fuel combustion products. Levoglucosan (4030 n g m(-3)), n-alkanes (1520 ng m(-3)), fatty acids (2629 ng m(-3)), and PAHs (57 ng m(-3)) in the haze samples were 3-40 times more abundant than those in nonevent samples. Approximately 30-90% ofthe organics during the haze period can be attributed to wheat straw burning. Concentrations of particulate material (PM) mass, n-alkanes, and low molecular weight (LMW) PAHs showed a unimodal size distribution, peaking at 0.7-1.1 microm during the hazy days, and a bimodal distribution, peaking at 0.7-1.1 microm and 4.7-5.8 microm during nonhazy days. The geometric mean diameters (GMDs) of organic aerosols are larger in the fine mode (<2.1 microm) during the hazy days, suggesting aerosols emitted from the wheat straw burning are larger than those from fossil fuel combustion, and fine particle coagulation and organic compound repartitioning were enhanced.