• 关键词：重庆  PM_2.5  含碳气溶胶  PMF源解析  污染事件

• 基金项目：国家自然科学基金（No.42077319）；国家重点研发计划重点专项（No.2018YFC0214003）；重庆市研究生科研创新项目（No.CYS20035）；重庆市技术创新与应用示范专项重点示范项目（No.cstc2019jscx-gksb0241）

• 冯婷
• 1. 重庆大学煤矿灾害动力学与控制国家重点实验室, 重庆 400044;2. 重庆大学环境科学系, 重庆 400044

• 蔡一鸣
• 1. 重庆大学煤矿灾害动力学与控制国家重点实验室, 重庆 400044;2. 重庆大学环境科学系, 重庆 400044

• 李振亮
• 重庆市生态环境科学研究院, 重庆 401147

• 杨复沫
• 四川大学环境科学与工程系, 成都 610065

• 王锋文
• 1. 重庆大学煤矿灾害动力学与控制国家重点实验室, 重庆 400044;2. 重庆大学环境科学系, 重庆 400044

• 摘要：于2015年10月、12月和2016年3月、8月在重庆大学A区采集秋、冬、春、夏4个季节PM_2.5样品，观察其微观形貌，分析含碳气溶胶及其碳组分的浓度水平，并探讨其季节变化及进行来源解析.结果表明，重庆沙坪坝区PM_2.5中有机碳（OC）、元素碳（EC）、烟灰（char）和烟炱（soot）的年均质量浓度分别为20.66、6.16、5.42和0.74 μg·m^-3.OC季节变化显著，冬季最高，夏季最低；EC秋季最高，冬季最低，但与其它季节相差不大；char表现为秋季 > 春季 > 冬季 > 夏季；soot表现为秋季 > 夏季 > 春季 > 冬季.正定矩阵因子（PMF）解析出3个因子，分别代表生物质/煤燃烧和道路扬尘的混合源（52.7%）、汽油机动车排放源（22.9%）和柴油机动车排放源（24.4%）.机动车尾气是秋、春和夏3个季节含碳气溶胶的主要来源，冬季主要受煤炭/生物质燃烧和道路扬尘混合源的影响.秋季污染事件可能是因为本地及周边城市汽油车通行量增加，冬季污染事件可能是本地煤炭/生物质燃烧排放增加和周边农村地区输入的共同作用，春季污染事件可能与来自西北方向的沙尘长距离传输有关.

• Abstract：Eighty-three PM_2.5 samples covering four seasons were collected at Chongqing University Campus A in October 2015 (autumn), December 2015 (winter), March 2016 (spring) and August 2016 (summer). The morphologies and elemental compositions of particles were detected by electron microscope coupled with Energy Dispersive Spectrometer. These samples were analyzed for carbonaceous pollutants, including OC, EC, char and soot, to understand their seasonal variation and source apportionment. The results showed that annual average concentrations of OC, EC, char, and soot were 20.66 μg·m^-3, 6.16 μg·m^-3, 5.42 μg·m^-3, and 0.74 μg·m^-3, respectively. The seasonal trend of OC was significant, highest in winter and lowest in summer; while EC was the highest in autumn, lowest in winter. Seasonal trend of char was ranked by the order of autumn> spring> winter> summer. Soot was ranked as: autumn>summer>spring>winter. The positive definite matrix factor (PMF) apportioned three sources, namely biomass/coal combustion and road dust (52.7%), source of gasoline motor vehicle emission (22.9%) and source of diesel motor vehicle emission (24.4%). Motor vehicle exhaust was the main source in autumn. While winter was mainly affected by the mixed sources of coal/biomass combustion and road dust. The episode in autumn might be caused by the increase of gasoline vehicles in the local and surrounding cities. The episode in winter might be due to the combination of increased local coal/biomass combustion emissions and input from surrounding rural areas. The episode in spring might be related to the long-distance transportation of dust from the northwest China.

• Key words：Chongqing  PM_2.5  carbonaceous aerosol  PMF source apportionment  pollution episodes

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