Global health care contributes approximately 5% of total global greenhouse gas emissions (CO₂ equivalents) to the atmosphere. For large health care systems in high income countries, direct emissions of inhaled anesthetics account for approximately 3% of their climate footprint and can make up more than half of carbon emissions from medical perioperative services.(1) In particular, sevoflurane ((CF₃)₂CHOCH₂F) has emerged as the most commonly used volatile gas in anesthetic care. Accurate and reliable parameters describing the atmospheric behavior and fate are key to understanding the impact of sevoflurane on climate and calculating its global warming potential (GWP). The GWP is a metric that scientific and regulatory communities rely upon when conducting environmental life cycle assessments and carbon footprint estimates. The periodic assessment reports by the Intergovernmental Panel on Climate Change (IPCC) and World Meteorological Organization (WMO) are often used as the primary references for GWP values to facilitate those estimates. It is therefore imperative that these reports reflect the most accurate and reliable parameters generated by the scientific research community. We recognize and applaud the ongoing efforts of the IPCC and WMO authors in reviewing and distilling large and continuously evolving streams of climate related data. With this present communication we would like to bring the issue outlined in the title to the attention of (a) the health care sustainability research community and (b) the authors of the soon to be completed (2022) WMO and IPCC assessment reports. As the healthcare sector addresses its impact on climate through technology and clinical practice choices, interest in the climate impact of halogenated inhaled anesthetic gases has expanded significantly over the past decade. In the early 2010s new experimental data to refine the atmospheric lifetime estimates and radiative efficiencies of general anesthetic gases halothane, isoflurane, desflurane, enflurane, and sevoflurane were available.(2,3) By 2012, the atmospheric fate of most of these compounds was well established,(4) with OH radical reaction kinetics parameters available for sevoflurane and later adopted by the JPL Data Evaluation Number 18 in 2015.(5) However, the sevoflurane GWP values presented in the IPPC AR5 (2013)(6) and WMO (2014)(7) reports did not reflect this most up-to-date information, instead using a lifetime of 2.2 years based on reaction kinetics reported in the older paper by Langbein et al.,(8) and reporting a GWP for the 100 year time horizon (GWP₁₀₀) of 216. Despite that the kinetic parameters of Langbein et al.(9) had been shown to be in error,(4) subsequent reports by the IPCC and WMO (2013, 2014, and 2018)(5,7,9) appear to have duplicated this error. This erroneous atmospheric lifetime translates into a significant overestimation of sevoflurane’s GWP, directly through the integration of the chemical decay rate, and indirectly through estimation of the radiative efficiency parameter, as the vertical mixing for such short-lived chemical species in the atmosphere is strongly moderated by actual lifetime. Table 1 gives a brief history of GWP literature values and a corrected value based on the current JPL kinetics recommendation and the updated Hodnebrog et al.(10) GWP calculation method. Using the temperature dependence for the reaction provided in the latest JPL Data Evaluation,(11) scaling relative to the OH kinetics/atmospheric lifetime of methyl chloroform (k_OH(272 K) = 6.14 × 10^–15 cm³ molecule^–1 s^–1, τ = 6.1 years),(2) and accounting for stratospheric lifetime (∼47 years), the atmospheric lifetime for sevoflurane is 1.4 years. In addition to a faster chemical decay rate in the GWP integration for a pulse of sevoflurane, the shorter lifetime decreases the calculated radiative efficiency from 0.367 (constant vertical profile) to 0.292 W m² ppb^–1 (lifetime-based atmospheric profile correction). Using an absolute GWP₁₀₀ for CO₂ of AGWP₁₀₀(CO₂) = 9.17 × 10^–14 W m^–2 yr (kg CO₂)⁻¹ (IPCC AR5 2013),(6) this translates into a GWP of 127 for a 100 year time horizon, which is 31–41% smaller than the GWP values recommended by the IPCC/WMO during the past decade. Hodnebrog et al.(6) is the most recent entry in the literature in 2020 that reports a GWP value for sevoflurane. They employ a revised AGWP₁₀₀(CO₂) of 8.064 × 10^–14 W m^–2 yr (kg CO₂)⁻¹, a revised Pinnock curve, and present updated GWPs for approximately 250 compounds. The impulse response function for CO₂ needs updating periodically, and the resulting change in AGWP₁₀₀(CO₂) impacts all GWP values upward. As a result, Hodnebrog et al.(5) report the GWP(100) for sevoflurane as 205 (up from 185, based on a lifetime of 1.9 years). Using the updated AGWP(CO₂) as employed by Hodnebrog et al.,(6) but a lifetime of 1.4 years, results in a GWP₁₀₀ of 144, and GWP₂₀ and GWP₅₀₀ of 508 and 43, respectively. This value of GWP₁₀₀ is 30% smaller than those employed by WMO and IPPC over the past decade. This is a significant difference and has a substantial impact on the calculations associated with life cycle assessments in anesthesia and the health care sector. Mads Sulbaek Andersen received his Ph.D. in atmospheric chemistry from the University of Copenhagen in 2006. He was then a Comer Research Foundation Postdoctoral Fellow at University of California, Irvine. In 2010 he joined the Laboratory Studies and Modeling Group at the Jet Propulsion Laboratory (JPL) as a NASA postdoctoral research fellow and in 2014 he accepted a faculty position at California State University, Northridge, where he currently holds the title of associate professor of chemistry. He is also an associate professor (adjunct) at University of Copenhagen, Denmark. In his research he employs advanced laboratory techniques to investigate kinetics and mechanisms of chemical reactions relevant to our atmosphere and the environment. He has published more than 70 scientific research articles in the field of environmental science. This article references 12 other publications.

中文翻译：

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麻醉气体七氟醚的全球变暖潜势需要重大修正

全球医疗保健向大气排放的温室气体总量（CO ₂当量）约占全球总排放量的 5% 。对于高收入国家的大型医疗保健系统，吸入麻醉剂的直接排放约占其气候足迹的 3%，可占围手术期医疗服务碳排放的一半以上。(1) 特别是七氟烷 ((CF ₃ ) ₂ CHOCH ₂F) 已成为麻醉护理中最常用的挥发性气体。准确可靠的描述大气行为和归宿的参数是了解七氟醚对气候影响和计算其全球变暖潜能值 (GWP) 的关键。GWP 是科学和监管团体在进行环境生命周期评估和碳足迹估算时所依赖的指标。政府间气候变化专门委员会 (IPCC) 和世界气象组织 (WMO) 的定期评估报告经常被用作 GWP 值的主要参考资料，以促进这些估计。因此，这些报告必须反映科学研究界产生的最准确和可靠的参数。我们认可并赞赏 IPCC 和 WMO 作者在审查和提炼大量不断变化的气候相关数据流方面所做的持续努力。通过本次通讯，我们希望提请 (a) 卫生保健可持续性研究界和 (b) 即将完成的（2022 年）WMO 和 IPCC 评估报告的作者注意标题中概述的问题。随着医疗保健部门通过技术和临床实践选择解决其对气候的影响，在过去十年中，人们对卤化吸入麻醉气体对气候影响的兴趣显着增加。在 2010 年代初期，新的实验数据改进了一般麻醉气体氟烷、异氟烷、地氟烷、安氟烷的大气寿命估计和辐射效率，₁₀₀) 的 216。尽管 Langbein 等人 (9) 的动力学参数已被证明是错误的，(4) IPCC 和 WMO 随后的报告（2013、2014 和 2018）(5,7,9)似乎重复了这个错误。这种错误的大气寿命转化为对七氟醚 GWP 的显着高估，直接通过化学衰变率的积分，间接通过辐射效率参数的估计，因为大气中这种短寿命化学物质的垂直混合受到强烈缓和按实际寿命。表 1 给出了 GWP 文献值的简要历史和基于当前 JPL 动力学建议和更新的 Hodnebrog 等人（10）GWP 计算方法的修正值。使用最新的 JPL 数据评估中提供的反应的温度依赖性，k _OH (272 K) = 6.14 × 10 ^–15 cm ³分子^–1 s ^–1 , τ = 6.1 年),(2) 考虑到平流层寿命（~47 年），七氟醚的大气寿命为 1.4 年。除了七氟醚脉冲的 GWP 积分中更快的化学衰减率之外，更短的寿命将计算出的辐射效率从 0.367（恒定垂直剖面）降低到 0.292 W m ² ppb ^–1（基于寿命的大气剖面校正）。对于AGWP ₁₀₀ (CO ₂ ) = 9.17 × 10 ^–14 W m ^{–2 的}CO ₂使用绝对 GWP ₁₀₀yr (kg CO ₂ ) ^-1 (IPCC AR5 2013),(6) 这意味着 100 年时间范围内的 GWP 为 127，比 IPCC/WMO 建议的 GWP 值小 31-41%上个年代。Hodnebrog 等人 (6) 是 2020 年文献中的最新条目，报告了七氟醚的 GWP 值。他们采用修订后的 AGWP ₁₀₀ (CO ₂ ) 为 8.064 × 10 ^–14 W m ^–2 yr (kg CO ₂ ) ^-1，修订后的 Pinnock 曲线，并提供大约 250 种化合物的更新 GWP。CO ₂的脉冲响应函数需要定期更新，AGWP ₁₀₀ (CO ₂) 向上影响所有 GWP 值。因此，Hodnebrog 等人 (5) 报告七氟醚的 GWP(100) 为 205（高于 185，基于 1.9 年的寿命）。使用Hodnebrog 等人采用的更新 AGWP(CO ₂ )，(6) 但寿命为 1.4 年，导致 GWP ₁₀₀为 144，GWP ₂₀和 GWP ₅₀₀分别为 508 和 43。这个 GWP 值₁₀₀比过去 10 年 WMO 和 IPPC 所采用的规模小 30%。这是一个显着的差异，对与麻醉和医疗保健部门的生命周期评估相关的计算产生重大影响。Mads Sulbaek Andersen 获得了博士学位。2006 年获得哥本哈根大学大气化学博士学位。当时他是加州大学欧文分校的 Comer Research Foundation 博士后研究员。2010 年，他加入喷气推进实验室 (JPL) 的实验室研究和建模小组，担任 NASA 博士后研究员，2014 年，他接受了加州州立大学北岭分校的教职，目前在那里他拥有化学副教授的头衔。 . 他还是丹麦哥本哈根大学的副教授（兼职）。在他的研究中，他采用先进的实验室技术来研究与我们的大气和环境相关的化学反应的动力学和机制。在环境科学领域发表科研论文70余篇。本文引用了 12 篇其他出版物。