中文摘要：

要有效地减少城市碳排放和正确地判断城市现有减排措施的有效性就必须准确地确定城市大气CO2的来源.由于碳同位素比从污染源到受体的传输过程中同位素分馏现象不明显,本研究建立了一套基于碳同位素比技术定量估算城市大气CO2来源的方法,并用该方法初步定量分析了上海市嘉定区大气CO2中来自燃煤、机动车尾气和生物质贡献的时空分布.上海市嘉定区大气CO2的上述3种来源中,生物质的贡献最大.燃煤的贡献在夜间（00：00、04：00和20：00）多于白天（08：00、12：00和16：00）,且随高度的升高而增大;机动车尾气的贡献则随高度的升高而降低.大气CO2浓度时空分布特征体现了上海市郊嘉定区大气CO2的排放特征和各来源的传输特性.

英文摘要：

To effectively reduce urban carbon emissions and verify the effectiveness of currently project for urban carbon emission reduction,quantitative estimation sources of urban atmospheric CO2 correctly is necessary.Since little fractionation of carbon isotope exists in the transportation from pollution sources to the receptor,the carbon isotope composition can be used for source apportionment.In the present study,a method was established to quantitatively estimate the source of urban atmospheric CO2 by the carbon isotope composition.Both diurnal and height variations of concentrations of CO2 derived from biomass,vehicle exhaust and coal burning were further determined for atmospheric CO2 in Jiading district of Shanghai.Biomass-derived CO2 accounts for the largest portion of atmospheric CO2.The concentrations of CO2 derived from the coal burning are larger in the night-time（00：00,04：00 and 20：00） than in the daytime（08：00,12：00 and 16：00）,and increase with the increase of height.Those derived from the vehicle exhaust decrease with the height increase.The diurnal and height variations of sources reflect the emission and transport characteristics of atmospheric CO2 in Jiading district of Shanghai.