【作者】 钱佳；

【导师】 周家斌；

【作者基本信息】 武汉理工大学 ， 环境工程， 2010， 硕士

【摘要】 大气颗粒物对于全球气候、生态环境和人体健康有着重要影响,随着我国经济的快速发展和城市化进程的加快,大气细粒子污染增多,灰霾天气频发,大气复合污染特征日益凸现。探究颗粒物化学组成,并定量解析颗粒物来源的分担率,成为制定大气污染防治对策的关键问题。本论文以大气PM2.5为研究对象,采集了武汉市东南部地区2009年夏冬两季的PM2.5样品,利用气相色谱一质谱(GC-MS)技术定量分析了饱和烃和多环芳烃化合物组成,旨在探讨城市典型地区大气颗粒有机物的分布特征和主要影响因素,并运用基于有机示踪的化学质量平衡(CMB)模型解析了主要污染源的贡献率。武汉冬季和夏季大气PM2.5的质量浓度分别为78.6～302.4μg·m-3、25.0-137.8μg·m-3,经过化学组分的质量平衡计算,得到的烷烃和多环芳烃质量约占细粒子质量的5.5%。PM2.5中的正构烷烃的浓度在冬季和夏季分别为9.6～123.1ng·m-3、22.9～96.1ng·m-3:CPI值冬季为1.8-3.6、夏季为1.4-2.6,表明武汉市大气细粒子在不同程度上受到高等植物蜡等现代生物来源的影响。普通检测出四种藿烷和甾烷等分子示踪物,在夏季和冬季分别为0.28～1.25ng·m-3、0.78～8.42ng·m-3,证实了大气细粒子明显受到化石燃料残余物的污染,在冬季受影响程度相对大一些。PM2.5中的多环芳烃的浓度在冬季和夏季分别为3.5～28.1ng·m-3、0.7～3.1ng·m-3,冬季明显高于夏季,可能与冬季的逆温天气而导致大气污染物不易扩散有关。基于有机分子示踪技术,建立了化学质量平衡(CMB)受体模型,成功解析出武汉大气颗粒物有机碳和PM2.5的来源。研究表明,冬季食物烹饪源对PM2.5中有机碳的贡献值为1.51～88.99μg·m-3为最高、其次为木质燃烧1.23～12.36μg·m-3、最低为燃煤排放0.02～2.01μg·m-3;武汉夏季食物烹饪源对PM2.5的贡献值为4.58～33.07μg·m-3为最高、其次为木质燃烧1.02～13.45μg·m-3和机动车排放为0.31～2.28μg·m-3、燃煤排放0.02～2.22μg·m-3为最低。在冬季,食物烹饪对武汉PM2.5的贡献率最高为14.15%、其次为木质燃烧(2.39%)和机动车排放(1.57%)；在夏季,主要来自食物烹饪(18.64%)和木质燃烧(5.18%)的贡献。更多还原

【Abstract】 Atmospheric particles have an important influence on global climate, ecological environment and human health. As economic development and urbanization process, air quality is becoming worse in recent years, including haze and mixed air pollution. Investigation of the chemical composition of particles, and source apportion is urgently required for air pollution control strategy. Atmospheric PM2.5 samples were collected from an urban site in summer and winter of 2009. And organics were quantitatively measured by ultrasonic extraction-GC/MS technique. Some organic compounds including 24 n-alkane species,4 hopane/cholestane species and 16 polycyclic aromatic hydrocarbon (PAHs) species were identified and quantified. The primary emission source contributions to fine organic carbon (OC) and fine particulate matter (PM2.5) mass concentrations on a daily basis in Wuhan were apportioned by organic tracers based chemical mass balance (CMB) receptor model.Atmospheric concentration of PM2.5, winter and summer, were 78.6～302.4μg·m-3, and 25.0～137.8μg·m-3, respectively. All quantified hydrocarbons accounts for 5.5% of PM2.5 mass concentration using chemical mass balance obtained the quality of hydrocarbons fine particle mass of 5.5%.The concentration of n-alkanes in winter and summer were 9.6～123.1ng·m-3, 22.9～96.1ng·m-3,respectively. CPI value in winter (1.8～3.6) are much higher than that of summer (1.4～2.6), which indicating that atmospheric fine particles in Wuhan City is affected in varying degrees by higher plant wax input. Four hopanes/steranes and other molecular tracers, in the summer and winter, is 0.28～1.25ng-m-3,0.78～8.42ng·m-3, respectively. It confirmed that the atmospheric fine particles apparently polluted by fossil fuel residues.PAHs of PM2.5 concentration in the winter and summer were 3.5～28.1ng·m-3, 0.7～3.1ng·m-3, respectively. Higher PAHs loads in winter may be caused by inversion weather and sources emissions.Based on organic tracer technology, a chemical mass balance (CMB) receptor model was successfully set up and employed to source apportionment of organic carbon and PM2.5 in Wuhan.The result shows that food cooking source in winter contribute 1.51～88.99μg·m-3, followed by wood burning (1.23～12.36μg·m-3), whereas coal-burning emissions is the lowest (0.02～2.01μg·m-3); It is noted that OC in summer of Wuhan has the similar source strength input characteristics, food cooking (4.58～33.07μg·m-3), wood burning (1.02～13.45μg·m-3), coal-fired emissions is the lowest (0.02～2.22μg·m-3).In winter, the food cooking on the contribution of PM2.5 is highest 14.15%, followed by biomass burning (2.39%) and motor vehicle emissions (1.57%); in the summer, food cooking (18.64%) and biomass burning (5.18%) were the highest.更多还原