Updated global warming potentials of inhaled halogenated anesthetics, isoflurane and sevoflurane from new temperature dependent OH-kinetics

Abstract

Despite the use of scavenging systems in anesthesia machines, inhaled halogenated anesthetic gases (HAGs), such as isoflurane (CF3CHClOCHF2) and sevoflurane ((CF3)2CHOCH2F), are still emitted directly into the atmosphere. In 2014, their atmospheric concentrations were 0.097 ppt (isoflurane) and 0.13 pptv (sevoflurane). As halogenated species, their impact on global warming has to be known. Notably, the global warming potential at a time horizon of 100 years (GWP100 years) for sevoflurane differs between IPCC and WMO sources, creating regulatory uncertainty. For that reason, in this work GWP100 years for isoflurane and sevoflurane was reevaluated from the atmospheric chemical lifetimes, τOHHAG, derived from the kinetic study of the gas-phase reactions of hydroxyl (OH) radicals with the HAGs and the radiative efficiencies (REs) derived from the (IR) absorption cross sections in the atmospheric window (1500–500 cm−1). The temperature dependence of the OH-rate coefficients (k1(T) for isoflurane and k2(T) for sevoflurane) between 263 and 353 K was determined at 100 Torr by using the pulsed laser photolysis/laser-induced fluorescence technique. The obtained Arrhenius expressions are k1(T) = (1.1 ± 0.5) × 10−13 exp{−(1234 ± 144)/T} and k2(T) = (1.6 ± 0.7) × 10−12 exp{−(1065 ± 138)/T} cm3 molecule−1 s−1. At 272 K, a τOHHAG of 3.0 years for isoflurane and 1.2 years for sevoflurane were estimated relative to CH3CCl3 from k1 and k2. Moreover, the ultraviolet (UV) absorption cross sections were determined between 190 and 400 nm at 298 K, and the absorption was found to be negligible above 290 nm, indicating minimal photolysis by sunlight. In contrast, the IR absorption in the atmospheric window is significant and the IR absorption cross sections (4000–500 cm−1) were determined by Fourier Transform infrared spectroscopy. The lifetime-corrected radiative efficiencies (REs) were 0.44 and 0.30 W m−2 ppbv−1 for isoflurane and sevoflurane, respectively. From lifetime-corrected REs and τOHHAG, GWP100 years was estimated to be 508 for isoflurane (5% lower than IPCC/WMO values) and 125 for sevoflurane (36% lower than IPCC and 11% lower than WMO). These findings confirm isoflurane to be a high-GWP gas (above 150) according to the EU 2024 regulation, while sevoflurane does not meet the high-GWP threshold. A reassessment of the IPCC and WMO values is recommended.

Graphical abstract: Updated global warming potentials of inhaled halogenated anesthetics, isoflurane and sevoflurane from new temperature dependent OH-kinetics

Supplementary files

Article information

Article type
Paper
Submitted
24 Jan 2025
Accepted
04 Jun 2025
First published
13 Jun 2025
This article is Open Access
Creative Commons BY-NC license

Environ. Sci.: Processes Impacts, 2025, Advance Article

Updated global warming potentials of inhaled halogenated anesthetics, isoflurane and sevoflurane from new temperature dependent OH-kinetics

S. Espinosa, F. Martínez, M. Antiñolo, O. J. Nielsen and E. Jiménez, Environ. Sci.: Processes Impacts, 2025, Advance Article , DOI: 10.1039/D5EM00061K

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements