HCFC‐133a (CF₃CH₂Cl): OH rate coefficient, UV and infrared absorption spectra, and atmospheric implications

Abstract

HCFC‐133a (CF3CH2Cl), an ozone‐depleting substance, is primarily removed from the atmosphere by gas‐phase reaction with OH radicals and by UV photolysis. The rate coefficient, k, for the OH + HCFC‐133a reaction was measured between 233 and 379 K and is given by k(T) = (9.32 ± 0.8) × 10−13 exp(−(1296 ± 28)/T), where k(296 K) was measured to be (1.10 ± 0.02) × 10−14 (cm3 molecule−1 s−1) (2σ precision uncertainty). The HCFC‐133a UV absorption spectrum was measured between 184.95 and 240 nm at 213–323 K, and a spectrum parameterization is presented. The HCFC‐133a atmospheric loss processes, lifetime, ozone depletion potential, and uncertainties were evaluated using a 2‐D atmospheric model. The global annually averaged steady state lifetime and ozone depletion potential (ODP) were determined to be 4.45 (4.04–4.90) years and 0.017 (±0.001), respectively, where the ranges are based solely on the 2σ uncertainty in the kinetic and photochemical parameters. The infrared absorption spectrum of HCFC‐133a was measured, and its global warming potential was determined to be 380 on the 100 year time horizon.

Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF3 CH2 Cl)

“…A radiative efficiency of 0.15 W m −2 ppb −1 (with a 23% uncertainty based on a 5%–95% confidence interval) was recently computed for HCFC‐133a based on measurements of its absorption cross section [ Etminan et al , ]. In the same study, the Global Warming Potential (GWP) for a 100 years time horizon was computed as 340, in reasonable agreement with the study by McGillen et al [], in which a GWP of 380 was calculated.…”

“…Its tropospheric sink is dominated by the reaction with the hydroxyl radical (OH) [ Sander et al , , and references therein]. Recent laboratory and modeling studies by McGillen et al [] revealed good agreement with these earlier studies and yielded a tropospheric lifetime of 4.65 years, which is also in good agreement with that proposed by Carpenter et al []. However, the recent study by McGillen et al [], which included new measurements of UV photolysis rates, yielded a stratospheric lifetime of 103 years and is in disagreement with those reported by Laube et al [] and Carpenter et al [].…”

Global warming potential estimates for the C<sub>1</sub>–C<sub>3</sub> hydrochlorofluorocarbons (HCFCs) included in the Kigali Amendment to the Montreal Protocol

“…b Rate coefficients taken from NASA evaluation unless noted otherwise. c Rate coefficient and metrics taken from McGillen et al (2015) with RE lifetime adjusted and a factor of +1.1 for stratospheric temperature correction applied. (Table 1) with rate coefficients recommended in Burkholder et al (2015).…”

“…Presently, there is no simple means to determine stratospheric lifetimes without the use of atmospheric models. Here, we have estimated stratospheric OH loss lifetimes, τ OH Strat , following a methodology similar to that used in the WMO (2014) ozone assessment, where results from 2-D atmospheric model calculations are used to establish a correlation between tropospheric (McGillen et al, 2015) and the PNNL database (Sharpe et al, 2004) were used in the analysis. b Rate coefficients taken from NASA evaluation unless noted otherwise.…”

Continued increase of CFC-113a (CCl<sub>3</sub>CF<sub>3</sub>) mixing ratios in the global atmosphere: emissions, occurrence and potential sources

“…In contrast, HCFC-133a strongly correlates with CFC-113a in the first 3 years ( Table 2). The tropospheric lifetime of HCFC-133a is 4-5 years (McGillen et al, 2015), and its mixing ratios have varied in recent years. They increased in 2012/2013 and decreased in 2014/2015 (Vollmer et al, 2015).…”