Estimate of Hydrochlorofluorocarbons (HCFCs) Emission Variations During 2011-2018 in the Yangtze River Delta, China

Hydrochlorofluorocarbons (HCFCs) with reduced ozone depletion potentials (ODPs) and high global warming potentials (GWPs) are used as temporal substitutes of chlorofluorocarbons, and were regulated by the Montreal Protocol and its adjustment with the 2013 cap and until a complete phase-out by 2030 in Article 5 (developing) countries. Weekly flask measurements for four HCFCs (HCFC-22, HCFC-141b, HCFC-142b, and HCFC-124) were conducted at Lin’an regional background station in the Yangtze River Delta (YRD) over the period of 2011-2018 and the measurements of HCFC-132b and HCFC-133a were started in 2018. The HCFCs emissions in YRD were estimated based on the tracer ratio method using CO and HFC-134a as multi-tracers and the estimated emissions of HCFCs based on CO and HFC-134a agreed well within the uncertainties of each other. The YRD’s HCFC emissions based on CO tracer were 28.8 ± 14.1 kt yr-1 for HCFC-22, 5.8 ± 3.4 kt yr-1 for HCFC-141b, 1.3 ± 0.6 kt yr-1 for HCFC-142b, 0.14 ± 0.11 kt yr-1 for HCFC-124, 0.025 ± 0.022 kt yr-1 for HCFC-132b, and 0.40 ± 0.35 kt yr-1 for HCFC-133a in 2018. HCFC-141b, HCFC-142b, and HCFC-124 emissions have reached peaks during the period of freezing consumption (2013-2014) or the period without emission control (2011-2012) and have all recently undergone substantial declines of 18%, 45%, and 30% in 2018 compared with those for 2011-2012. HCFC-22 emissions showed steadily increased during 2011-2018, but the rate of increase in 2018 was obviously slower than the two previous periods. The YRD’s cumulative emissions, ODP-weighted and CO2-equivalent emissions of the four HCFCs accounted for 20%, 23%, and 18% of the national totals, respectively, for 2011-2017, and the HCFC-133a emissions in the YRD provided 70% to the eastern China emissions and 18% to the global emissions in 2018, thus are important contribution to China’s total emissions and even worldwide.