CFCs measurements at high altitudes in northern China during 2017-2018: Concentrations and potential emission source...

Northern China was simulated as the main contributor to global chlorofluorocarbon (CFCs) that slowed down the recovery of stratospheric ozone layer in most recent studies. An atmospheric campaign was carried out from June 2017 to April 2018 to register the concentrations of typical chlorofluorocarbons (CFCs) (i.e., CFC-11, CFC-12, CFC-113, and CFC-114) at the top of Mount Tai, northern China. The mixing ratios of CFC-11 CFC-12, CFC-113, and CFC-114 were 257, 577, 80, and 18 pptv, respectively. These values are similar to the reported data 10 years ago at Mount Tai. CFC concentrations correlated well with those of benzene (an anthropogenic tracer) and were not affected by either humidity, temperature, or solar radiation. However, CFC concentrations were considerably influenced by regional transport: their backward trajectory and the PSCF (potential source contribution function) analysis suggested that higher concentrations (CFC-12, CFC-113 and CFC-114) were detected under the influence of air mass from the industrial regions in mid-eastern China and CFC-11 was through long-range transport from northwestern (i.e., from the higher atmosphere in western China) air masses. Overall, the findings of this study suggested that CFCs still have emissions in China, but no significant increase in recent years. Mid-eastern China might be responsible for the CFC emissions. The conclusions also highlight the need for the enforcement of effective control policies and the management of emissions, in order to avoid increasingly severe scenarios.