Global and regional atmospheric measurements and modeling can play key roles in discovering and quantifying unexpected nascent emissions of environmentally important substances. We focus here on three hydrochlorofluorocarbons (HCFCs) that are restricted by the Montreal Protocol because of their roles in stratospheric ozone depletion. Based on measurements of archived air samples and on in situ measurements at stations of the Advanced Global Atmospheric Gases Experiment (AGAGE) network, we report global abundances, trends, and regional enhancements for HCFC-132b (CH2ClCClF2), which is newly discovered in the atmosphere, and updated results for HCFC-133a (CH2ClCF3) and HCFC-31 (CH2ClF). No purposeful end-use is known for any of these compounds. We find that HCFC-132b appeared in the atmosphere 20 y ago and that its global emissions increased to 1.1 Gg⋅y⁻¹ by 2019. Regional top-down emission estimates for East Asia, based on high-frequency measurements for 2016–2019, account for ∼95% of the global HCFC-132b emissions and for ∼80% of the global HCFC-133a emissions of 2.3 Gg⋅y⁻¹ during this period. Global emissions of HCFC-31 for the same period are 0.71 Gg⋅y⁻¹. Small European emissions of HCFC-132b and HCFC-133a, found in southeastern France, ceased in early 2017 when a fluorocarbon production facility in that area closed. Although unreported emissive end-uses cannot be ruled out, all three compounds are most likely emitted as intermediate by-products in chemical production pathways. Identification of harmful emissions to the atmosphere at an early stage can guide the effective development of global and regional environmental policy.

全球和区域大气测量和建模可以在发现和量化对环境重要的物质的意外新生排放方面发挥关键作用。我们在此重点关注三种受《蒙特利尔议定书》限制的氢氯氟碳化合物 (HCFC)，因为它们会导致平流层臭氧消耗。根据对存档空气样本的测量以及先进全球大气气体实验 (AGAGE) 网络站的现场测量，我们报告了 HCFC-132b (CH2ClCClF2) 的全球丰度、趋势和区域增强情况，HCFC-132b ( CH2ClCClF2 ) 是在大气，以及 HCFC-133a ( CH2ClCF3 ) 和 HCFC-31 ( CH2 ClF) 的更新结果。这些化合物的最终用途尚不清楚。我们发现 HCFC-132b 20 年前就出现在大气中，到 2019 年其全球排放量增加到 1.1 Gg⋅y ^−1。东亚区域自上而下的排放量估算基于 2016-2019 年的高频测量，在此期间，HCFC-132b 排放量占全球 HCFC-132b 排放量的 95%，占全球 HCFC-133a 排放量 2.3 Gg⋅y ⁻¹的 80%。同期 HCFC-31 的全球排放量为 0.71 Gg⋅y ⁻¹ 。欧洲在法国东南部发现的少量 HCFC-132b 和 HCFC-133a 排放量于 2017 年初停止，当时该地区的一家碳氟化合物生产设施关闭。尽管不能排除未报告的排放最终用途，但所有三种化合物很可能作为化学品生产途径中的中间副产品排放。 尽早识别大气中的有害排放物可以指导全球和区域环境政策的有效制定。