title: Atmospheric Fossil Fuel CO2 Traced by Δ(14)C in Beijing and Xiamen, China: Temporal Variations, Inland/Coastal Differences and Influencing Factors.
abstract: One year of atmospheric Δ(14)CO2 were observed in 2014 in the inland city of Beijing and coastal city of Xiamen, China, to trace temporal CO2ff variations and to determine the factors influencing them. The average CO2ff concentrations at the sampling sites in Beijing and Xiamen were 39.7 ± 36.1 ppm and 13.6 ± 12.3 ppm, respectively. These contributed 75.2 ± 14.6% and 59.1 ± 26.8% to their respective annual ΔCO2 offsets over background CO2 concentrations. Significantly (p < 0.05) high CO2ff values were observed in winter in Beijing. We did not find any significant differences in CO2ff values between weekdays and weekends. Diurnal CO2ff variations were plainly evident, with high values between midnight and 4:00, and during morning and afternoon rush hours. The sampling site in the inland city of Beijing displayed much higher CO2ff inputs and overall temporal variations than the site in the coastal city of Xiamen. The variations of CO2ff at both sites were controlled by a combination of emission sources, topography, and atmospheric dispersion. In particular, diurnal observations at the urban site in Beijing showed that CO2ff was easily accumulated under the southeast wind conditions.
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Zhenchuan
authors.initials: Z
authors.lastname: Niu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.|Xi'an Jiaotong University , Xi'an, China.
authors.forename: Weijian
authors.initials: W
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Shugang
authors.initials: S
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Xiaohu
authors.initials: X
authors.lastname: Xiong
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Du
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.|Shaanxi Provincial Key Laboratory of Accelerator Mass Spectrometry Technology and Application, Xi'an AMS Center , Xi'an, China.
authors.forename: Yunchong
authors.initials: Y
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an, China.
authors.forename: Gehui
authors.initials: G
authors.lastname: Wang
mesh_terms: D000393:Air Pollutants; D000068476:Beijing; D002681:China; D004784:Environmental Monitoring; D005579:Fossil Fuels
chemical_list: D000393:Air Pollutants; D005579:Fossil Fuels