Laboratory for Air Pollution and Environmental Technology, Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland;
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093.
Proc Natl Acad Sci U S A. 2021 Feb 2;118(5). doi: 10.1073/pnas.2010914118.
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 ([Formula: see text]), which is newly discovered in the atmosphere, and updated results for HCFC-133a ([Formula: see text]) and HCFC-31 ([Formula: see text]ClF). 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 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 during this period. Global emissions of HCFC-31 for the same period are 0.71 Gg⋅y 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环境重要物质新生排放方面发挥关键作用。我们这里重点关注三种因在平流层臭氧消耗中起作用而受《蒙特利尔议定书》限制的含氯氟烃（HCFCs）。基于对存档空气样本的测量和大气综合全球观测站（AGAGE）网络站点的现场测量，我们报告了新发现于大气中的 HCFC-132b([Formula: see text])的全球丰度、趋势和区域增强，以及 HCFC-133a([Formula: see text])和 HCFC-31([Formula: see text]ClF)的更新结果。这些化合物均没有已知的特定用途。我们发现，HCFC-132b 大约 20 年前出现在大气中，其全球排放量到 2019 年增加到 1.1 Gg⋅y。基于 2016-2019 年高频测量的东亚区域自上而下排放估算，占全球 HCFC-132b 排放的约 95%，占同期全球 HCFC-133a 排放量（2.3 Gg⋅y）的约 80%。同期全球 HCFC-31 排放量为 0.71 Gg⋅y。法国东南部发现的小量欧洲 HCFC-132b 和 HCFC-133a 排放于 2017 年初停止，当时该地区的一个氟碳化合物生产设施关闭。虽然不能排除无报告排放源，但所有这三种化合物很可能是作为化学生产途径中的中间副产物排放的。早期识别对大气有害的排放物可以为制定有效的全球和区域环境政策提供指导。
