广州城区大气颗粒物中典型生物质燃烧示踪物特征分析

在广州城区夏秋两季采集分粒径颗粒物样品，通过分析获得其中多种典型生物质燃烧示踪物（左旋葡聚糖（LG）、甘露聚糖（MN）和水溶性钾离子（K⁺））以及有机碳（OC）等含碳组分资料，进而探讨广州城区生物质燃烧颗粒类型及生物质燃烧源对有机碳的影响。结果表明，大气颗粒物中生物质燃烧示踪物均在0.44~1.00 μm粒径区间占比最高。细颗粒中呈现出高LG/MN和K⁺/LG比值特征，与农作物残余物燃烧源颗粒物的排放特征一致。广州秋季LG/OC比值与国内其他城市在生物质燃烧影响严重季节的水平相当。利用受体模型估算出生物质燃烧源对广州夏季和秋季OC的平均贡献分别为10.8%和28.1%，说明秋收时期周边区域农作物残余物燃烧是广州城区不可忽视的大气污染源。据此，提供相应的防治建议。

Characterization of typical biomass burning tracers among atmospheric particles in urban Guangzhou

Size-resolved particle samples were collected at an urban site of Guangzhou during the summer and autumn.Samples were subjected to chemical analysis for obtaining various typical biomass burning tracers (levoglucosan (LG),mannosan (MN),and water-soluble potassium ion (K⁺)) and carbonaceous species including organic carbon (OC) in order to identify the major biomass burning particle type and quantify the contribution of biomass burning to OC abundance.Results showed that biomass burning tracers had dominant particle sizes of 0.44~1.00μm.High LG/MN and K⁺/LG ratios in the fine particle mode were found,which is consistent with the particle source profile emitted from agricultural residue burning.The LG/OC level during the autumn in urban Guangzhou was comparable to those in other Chinese cities during the biomass burning seasons.Based on a receptor model,the average contributions of biomass burning to OC during the summer and autumn were estimated to be 10.8% and 28.1h%,respectively,which implies that biomass burning sources,especially agricultural residue burning,cannot be ignored in the urban atmosphere in Guangzhou.Furthermore,relevant prevention suggestions were provided.