[ C-based Sources Partitioning of Atmospheric CO During Youth Olympic Games, Nanjing].

Observations of urban atmospheric CO molar fraction and its C isotope composition (δ C) is of great importance to interpret the effect of anthropogenic and biologic sources on local or regional carbon cycle. High-frequency in-situ observation on atmospheric in urban airsheds was performed during Youth Olympic Games (YOG) in Nanjing. The hourly, diurnal and daily differences of CO concentration and its δ C between the period with and without temporary CO emission controls were compared. The results showed that short-term emission reduction measures could cause 21×10 decrease in atmospheric CO concentration in a regional and short-term scale. The reduction of coal combustion during YOG in YRD was about 5%. The overall isotopic signature of local surface sources δ C in Yangtze River Delta (YRD) was determined by Miller-Tans, and the isotopic signatures of anthropogenic and natural sources in YRD were also determined based on literature investigation. According to the above results, the surface net CO flux, plant flux and anthropogenic flux in YRD were quantified using mass-balance equation. The CO emission from cement production (non-energy industrial process) was the key human factor of high atmospheric δ C of CO in YRD during summer (2.36‰). The plant effect could offset 23% to 39% anthropogenic CO emission in YRD during summer. In this study, we tried to provide new solution to partition carbon sources in urban areas by combining top-down atmospheric observation and traditional IPCC's emission inventory.