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Preliminary report: Analyses of tCFP’s potential impact on 

atmospheric ozone

Dong Wang, Seth Olsen, and Donald Wuebbles

Department of Atmospheric Sciences

University of Illinois, Urbana, IL 61801

Abstract 

Trans-1-chloro-3,3,3-trifluoropropylene (tCFP, CHCl=CHCF3) is a chemical compound 

proposed to substitute for currently used blowing agents due to tCFP possessing advantages for

fire safety, air quality, and climate properties. As a molecule containing a chlorine atom, tCFP 

might be of concern because of its potential to affect the amount of ozone in the global 

atmosphere. This study uses a state-of-the-art 3-D global atmosphere chemistry-climate model to 

evaluate such potential impacts. Our analyses indicate that that there is statistically zero (less 

than 0.01%) impact on global atmospheric (tropospheric and stratospheric) ozone abundance if 

tCFP were substituted for all compounds it might replace and assuming all of the tCFP used is

released into the atmosphere. We also found that a tCFP source strength of 21.72Tg/yr would be 

necessary to result in a decrease of annually-averaged global atmospheric ozone of 0.1%, a small 

but statistically significant impact. We also derived that the ODP of tCFP is 0.00024 assuming 

emissions occurring in the major parts of the world that are heavy users of the blowing agents 

tCFP might replace.

Introduction

Trans-1-chloro-3,3,3-trifluoropropylene (tCFP, chemical formula CHCl=CHCF3) has been

proposed as a potential substitute compound for currently used blowing agents with potential 

climate issues (the hydrofluorocarbons (HFCs) HFC-254a, -365mfc, -134a, -227ea and the 

hydrochlorofluorocarbons (HCFCs) HCFC-141b, -142b, -22) or with flammability and air 

quality concerns (the hydrocarbons (HC) c-Pentane, n-Pentane). However, tCFP contains 

chlorine, and possible stratospheric ozone loss from its release of chlorine to the atmosphere is of 

concern. We carry out this study in order to assess tCFP’s impact on ozone in the atmosphere 

with a state-of-the-art numerical model that simulates the chemistry and physics of the 

atmosphere. In particular, we are interested in how much the impact on atmospheric ozone would 

be if all blowing agents were substituted by tCFP and all tCFP used were released into the 

atmosphere. In addition, we are interested in how much tCFP would be necessary to result in 

0.1% loss in global ozone. We develop two emission cases to address these two questions. This 

is a brief report of our preliminary findings.
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Model description

For this study, we use the Whole Atmosphere Community Climate Model (WACCM) version 

3.5.48, an atmosphere chemistry-climate model developed by the National Center for 

Atmospheric Research (NCAR). The model has been evaluated and used in a number of 

scientific studies, for example, in the Stratospheric Processes and their Role in Climate (SPARC) 

2010 Report (Eyring et al., 2010). WACCM 3.5.48 numerically simulates the atmosphere from 

the surface up to 4.5 ×10-4Pa (~145km). The horizontal resolution is 2.5° longitude ×1.9° 

latitude. The model is run in offline mode, which means that the meteorological fields are 

provided by a previous run of WACCM 3.5 representing the year 2000 atmosphere (Garcia, 

private communication, 2007). The model simulates 125 chemical species and uses the JPL06 

recommendations (Sander et al., 2006) including extensions for non-methane hydrocarbon 

chemistry, which is key to good representation of tropospheric oxidative capacity. The model has 

good performance in simulating the stratosphere and the upper troposphere and lower 

stratosphere as shown in e.g., the Chemistry-Climate Model Validation Activity (CCMVal) 

(Eyring et al., 2010; Gettelman et al., 2010).

The tCFP decomposition in the atmosphere is primarily initiated by its reaction with hydroxyl 

radical (OH) in the troposphere. Here we adopt the most recent estimate of the reaction rate of 

4.4 × 10-13 cm3 molec-1s

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(Anderson et al., 2008), assuming no temperature dependence.

The Modeling Studies

Two different types of analyses are done in this study towards understanding the potential effects 

of tCFP on ozone. The first case, Perturbation 1, is designed to determine the maximum impact 

tCFP emissions, assuming tCFP use as a blowing agent, could possibly have on atmospheric 

ozone. We assume in this scenario the currently used blowing agents, as listed for different 

regions in Table 1 (Rajiv Singh, private communication, 2011), are completely substituted by 

tCFP. The estimated release rate into the atmosphere is around 20%; however, here we assume

that 100% of the tCFP used is released into the atmosphere, to study the maximum possible 

impact. Thus a global tCFP emission rate of 0.171 Tg/yr is derived. Based on the data in Table 1,

we calculate tCFP emissions for European Union, Japan, China, India, Turkey, Middle East and 

North Africa, Latin America and North America, assuming that within each region tCFP is 

uniformly emitted both spatially and temporally. Figure 1 depicts tCFP emissions distribution in 

perturbation 1 scenario.

The second case, Perturbation 2, examines how much tCFP would cause a 0.1% loss in global 

column ozone. A previous study by Patten and Wuebbles (2010) found that a 50.0 Tg/yr tCFP 

emission resulted in 0.321% decrease in global column ozone. Thus in the second scenario we 

assume globally 15.57 Tg tCFP is emitted into the atmosphere per year. The geographic pattern 

of this emission is the same as that in Figure 1, except that the emission rate is 91 times larger 

than that in Figure 1. It is expected to cause nearly 0.1% loss in total atmospheric ozone in this 
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scenario. In this study the model result can be different from being exactly 0.1% loss. In this 

case, we can scale the emission so as to achieve 0.1% ozone loss. This is justified because

previous studies have shown that within this still small magnitude of perturbation ozone changes 

linearly with emissions.

In addition to the two tCFP perturbation scenarios, we run a reference scenario which is identical 

to the perturbation scenarios except that no tCFP is emitted. The emissions and lower boundary 

concentrations of the major source gases correspond to year 2004 background atmosphere. NOx

source from lightning is 5.0 TgN, according to Schumann and Huntrieser (2007). The model setup is described in Patten et al. (2011).

Results

To ensure that the model is run to chemical steady state, we carry out seven years of simulation 

for each of the above stated scenarios. The year-to-year variation is less than 0.02% for ozone 

and less than 0.03% for tCFP. Only the seventh year’s result is shown here. 

The steady state global atmospheric burdens of tCFP derived for the two scenarios are 0.014 and 

1.313 Tg (Table 2) for Perturbations 1 and 2, respectively. These correspond to the assumed 

tCFP emissions of 0.171 and 15.57 Tg/yr, respectively. Based on these simulations, the firstorder estimate of tCFP’s lifetime is ~29.9 and ~30.8 days based on the first and second 

perturbation scenarios, respectively. These are lower than the ~ 40 day lifetime estimate of 

Patten and Wuebbles (2010). The difference may arise both from differences in the assumed 

emission distribution and from this study using an updated version of the atmospheric model. 

Simulated tCFP mixing ratios are highest near the surface in the Northern Hemisphere and 

decrease quickly with altitude, with extremely little tCFP reaching the Southern Hemisphere 

(Figures 2 and 3). Peak zonal mean mixing ratios are ~ 3.4 ppt for the Perturbation 1 scenario, 

the maximum possible real world emissions. In Perturbation 2, peak mixing ratios are as high as 

400 pptv. These features, mixing ratio decreases with altitude and decreases southward, are to be 

expected given tCFP’s short lifetime and its predominant emissions in the Northern Hemisphere.

In the first perturbation scenario the Cly (= Cl + 2×Cl + ClO + OClO + 2×Cl2O2 + HCl + HOCl + 

ClONO2 + BrCl) mixing ratio increased by no more than 10% in the troposphere, with more 

increase in the lower troposphere at northern mid- and high-latitudes (Figure 4). In the second 

perturbation scenario, the Cly mixing ratio increases to more than 6 times of that in the reference 

atmosphere in the lower northern troposphere (Figure 5). 

Figures 6 and 7 show the relative change (%) of annual, zonal mean ozone mixing ratios in the 

perturbation cases compared with those in the reference scenario. As shown in Figure 6, there is 

no systematic shift of ozone mixing ratios in the perturbation 1 scenario. These emissions result 

in a 0.0073% change in global ozone burden (Table 3). Changes of this magnitude are not 
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statistically significant from the model variability, and thus are not statistically different from 

zero. 

In Perturbation scenario 2, with the 15.57 Tg tCFP emission (designed specifically to achieve a 

statistically significant change), there is 0.072% total atmospheric ozone loss much of which 

occurs in the troposphere. As shown in Figure 6, there is 0.2%~0.8% ozone loss in troposphere 

in the northern hemisphere, with largest relative loss at high-latitudes. Overall tropospheric 

ozone decreases by 0.29%. Scaling this result we estimate that a 21.72 Tg per year tCFP 

emission would lead to a 0.1% loss in global ozone. Thus, in order for tCFP to have caused an 

ozone loss of 0.1% it would need to be emitted at a rate nearly two orders of magnitude greater 

than the worst case real world estimates used in Perturbation scenario 1. Also from this 

simulation we calculate the ODP of tCFP using an approach akin to that used in Patten and 

Wuebbles (2010). The derived ODP for this assumed distribution of emissions was found to be 

0.00024. Although this is slightly lower than the ODP of 0.00034 determined in Patten and 

Wuebbles (2010), it is similar in magnitude. As with the difference in lifetime this difference 

may arise both from differences in the assumed emission distribution and from this study using 

an updated version of the atmospheric model.

Conclusions

Our modeling study suggests that the potential impact of tCFP on ozone in the atmosphere is 

likely to be extremely small, essentially immeasurable. If currently used blowing agents were to 

be entirely replaced by tCFP and all of the tCFP used were released to the atmosphere, the 

impact on atmospheric ozone will be statistically zero (less than 0.01% change in total column 

ozone). To cause a statistically significant level of 0.1% loss in total column atmospheric ozone, 

tCFP emission must reach 21.72 Tg/yr, which is nearly 130 times above the current emissions of 

all blowing agents usage in 2010. The ODP for tCFP using the regionally assumed emissions in 

this study is 0.00024, an extremely small value.

References:

Andersen, M. P. S., Nilsson, E. J. K., Nielsen, O. J., Johnson, M. S., Hurley, M. D. and 

Wallington, T. J.: Atmospheric chemistry of trans-CF3CH=CHCl: Kinetics of the gas-phase 

reactions with Cl atoms, OH radicals, and O3. J. Photochem. Photobiol. A-Chem., 199, 92-97, 

2008. 

Eyring, V., T. G. Shepherd, and D. W. Waugh (Eds.): Stratospheric Processes And Their Role in 

Climate Report on the Evaluation of Chemistry-Climate Models (SPARC CCMVal). SPARC 

Report No. 5, WCRP-132, WMO/TD-No. 1526, accessed at 

http://www.atmosp.physics.utoronto.ca/SPARC, 2010.
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Gettelman, A., M. I. Hegglin, S. W. Son, M. Fujiwara, S. Tilmes, L. Pan, P. Hoor, H. Lee, G. L. 

Manney, T. Birner, G. Stiller, M. Rex, S. Kremser, D. Wuebbles, K. A. Walker, and J. A. Anel:

Upper Troposphere and Lower Stratosphere, in Stratospheric Processes And Their Role in 

Climate Report on the Evaluation of Chemistry-Climate Models (SPARC CCMVal), edited by 

V. Eyring, T. G. Shepherd, and D. W. Waugh, pp. 253-304, World Meteorological Organization, 

SPARC Report No. 5, WCRP-132, WMO/TD-No. 1526, World Climate Research Programme, 

accessed through http://www.atmosp.physics.utoronto.ca/SPARC, 2010.

Patten, K. O., V. G. Khamaganov, V. L. Orkin, S. L. Baughcum and D. J. Wuebbles: 2-Bromo3,3,3-Trifluoropropene: OH Reaction Rate Constant, IR Absorption Spectrum, Ozone Depletion 

Potentials and Global Warming Potential, in preparation, 2011. 

Patten, K. O. and D. J. Wuebbles: Atmospheric lifetimes and Ozone Depletion Potentials of 

trans-1-chloro-3,3,3-trifluoropropylene and trans-1,2-dichloroethylene in a three-dimensional 

model. Atmospheric Chemistry and Physics, 10, 10867-10874, 2010. 

Sander, S. P., R. R. Friedl, D. M. Golden, M. J. Kurylo, G. K. Moortgat, H. Keller-Rudek, P. H. 

Wine, A. R. Ravishankara, C. E. Kolb, M. J. Molina, B. J. Finlayson-Pitts, R. E. Huie, and V. L. 

Orkin: Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies, Evaluation 

Number 15, JPL Publication 06-2, NASA Panel for Data Evaluation, Jet Propulsion Laboratory, 

California Institute of Technology, Pasadena, California, July 10. Available via 

http://jpldataeval.jpl.nasa.gov, 2006.

Schumann, U. and H. Huntrieser: The global lightning-induced nitrogen oxides source, 

Atmospheric Chemistry and Physics, 7, 3823-3907, 2007. 
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Table 1. HFCs, HCFCs and hydrocarbons (HC) usage (in Mlbs) as blowing agents in 2010 in 

major regions of the world that have heavy users of blowing agents (Rajiv Singh, private 

communication, 2011).

EUaJapan China India Turkey MENAb L.A.c N.A.dtotal

total 83.4 15.0 116.2 22.0 11.5 22.9 39.9 65.8 376.7

 

a

EU: European Union

b MENA: Middle East and North Africa

c

L.A.: Latin America

d

N.A.: North America
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Table 2. Global tCFP emissions (Tg/yr) used in the model, and the derived atmospheric burdens 

(Tg) and lifetimes (days) in the two perturbation cases.

global emission (Tg/yr) atmospheric burden (Tg) lifetime (days)

Perturbation 1 0.171 0.014 29.9

Perturbation 2 15.57 1.313 30.8
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Table 3. Global atmospheric, tropospheric and stratospheric ozone burdens (Tg) derived in the 

model for the scenarios studied, and the determined percentage changes in ozone relative to the 

reference scenario.

global O3

% change 

from ref. trop. O3

% change 

from ref. strat. O3

% change 

from ref.

Reference 3139.86 369.18 2770.68

Perturbation 1 3140.09 +0.0073 369.20 +0.0054 2770.88 +0.0072

Perturbation 2 3137.60 -0.0717 368.12 -0.2881 2769.49 -0.0429
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Figure 1. The assumed tCFP emissions (molecules/cm2s) in the Perturbation 1 scenario.
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Figure 2. Annual, zonal mean tCFP mixing ratio (pptv) derived for Perturbation 1, the scenario in which currently used blowing 

agents have been substituted by tCFP and the used tCFP is completely released to the atmosphere.
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Figure 3. Annual, zonal mean tCFP mixing ratio (pptv) derived for the 15.57 Tg tCFP per year emission scenario. 
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Figure 4. Change (%) in annual, zonal mean Cly mixing ratio derived for Perturbation 1, the scenario in which currently used blowing 

agents have been substituted by tCFP and the used tCFP is completely released to the atmosphere, relative to the reference scenario. 
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Figure 5. Change (%) in annual and zonal mean Cly mixing ratio derived for the 15.57 Tg tCFP per year emission scenario

(Perturbation 2) relative to the reference scenario.
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Figure 6. Change (%) in annual, zonal mean ozone mixing ratio derived for Perturbation 1, the scenario in which currently used 

blowing agents have been substituted by tCFP and the used tCFP is completely released to the atmosphere. 
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Figure 7. Change (%) in annual, zonal mean ozone mixing ratio derived for the 15.57 Tg tCFP per year emission scenario

(Perturbation 2) relative to the reference scenario.