Using 14C of tree rings to study CO2 emissions from fossil sources at the sampling point of the Meteorological Tower in Beijing.

Atmospheric fossil fuel CO 2 information is an important reference for local government to formulate energy-saving and emission reduction in Beijing. We present a reconstruction of the fossil fuel CO 2 mole fraction from 2007 to 2014 near the Beijing meteorological tower using AMS to measure 14C of cedar tree rings. The results show that the mole fraction of fossil fuel CO 2 at the sampling point first decreased from 22.3 ± 0.7 ppm (2007) to 21.0 ± 0.9 ppm (2008), then increased to 22.5 ± 0.9 ppm (2010), and finally decreased to 18.7 ± 0.7 ppm (2014). This trend correlates (r = 0.958, p < 0.01) well with one third (May-August) of fossil source consumption of secondary industry in Beijing during 2007–2014. It is attributed to environmental policy programs and control measures at local scope in Beijing during 2007–2014. This study suggests that 14C measurements of tree rings by AMS provide an effective method to evaluate the effect of the environmental policies. [ABSTRACT FROM AUTHOR]