Estimates of major anthropogenic halocarbon emissions from China based on interspecies correlations

Halocarbon emissions from China are of great interest to both policy makers and academia. To estimate halocarbon emissions with interspecies correlation methods, previous studies adopted CO, HCFC-22 or other species as reference tracers. However, few of these studies compared the results using different reference tracers. In this study, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and carbon monoxide (CO) concentrations were measured at a monitoring site in northern China in 2009/2010, and halocarbon emissions were estimated using an interspecies correlation method. A comparison was performed of the correlations between estimated halocarbon emissions and two reference tracers, CO and HCFC-22. The results show that both species are significantly correlated with most of the target species (P < 0.01), whereas HCFC-22 shows better correlations than does CO. Our estimated halocarbon emissions for 2009 agree within uncertainties with results obtained with other approaches, including inverse modeling and interspecies correlation methods. The emissions for 2001–2009 estimated in different studies (all using top–down approaches) show a clear decrease in the emissions of CFC-11 and CFC-12 and an increase in the emissions of HCFC-22, HCFC-141b and HCFC-142b in China. Moreover, the combined Ozone Depletion Potential weighted emissions of CFCs are much greater than the reported consumption, whereas the emissions of HCFC counterparts are not more than one-half of the reported consumption. This result suggests that HCFCs are being accumulated in banks and that these banks will sustain elevated in China.