Request to Use an Alternate GWP for

Vinylidene Fluoride (CAS Number: 75-38-7)

Summary:

EPA recently promulgated a mandatory reporting regulation for Fluorinated Greenhouse 

Gases (F-GHG). The regulation requires facilities to monitor and report CO2-equivalent 

F-GHG process vent emissions, if those emissions exceed a threshold of 10,000 metric 

tons CO2-equivalent per year. [1] Estimated CO2-equivalent emissions are obtained by 

multiplying the F-GHG mass emissions by the Global Warming Potential for the 

individual fluorinated gases that comprise the flow. EPA has provided a table of 100-

year time horizon GWP values for about 70 individual F-GHG, and specifies that these 

values are to be used for the purpose of computing CO2-equivalent emissions. [2] A 

default GWP value of 2,000 is to be used for any F-GHG not listed in Table A-1. The 

regulation allows a facility to request a lower provisional GWP when clear scientific 

evidence exists to support such a lower value.

Table A–1 does not list a GWP for vinylidene fluoride. Vinylidene fluoride is a shortlived fluorinated alkene. The default GWP value of 2,000 is inappropriate for such gases 

and a substantial body of evidence in the peer-reviewed scientific literature has 

established that the GWPs of fluorinated alkenes are modest. Kinetic rate constants for 

the atmospheric degradation of vinylidene fluoride have been measured in an 

environmental chamber; the atmospheric lifetime of vinylidene fluoride has been 

estimated as 4 days; the infrared spectrum of vinylidene fluoride has been accurately 

measured and the GWP of vinylidene fluoride has been estimated as 0.9 relative to CO2

with a 100-year integration time horizon. DuPont is requesting a provisional GWP of 

0.9 be assigned for vinylidene fluoride.

Evidence Supporting Request:

F-GHG Identity: Vinylidene fluoride

Chemical Formula: C2H2F2

CAS Number: 75-38-7

Estimated GWP: 0.9 relative to CO2 with a 100-year integration time horizon

Data and analysis: Baasandorj et al. have measured kinetic rate constants for the 

vapor phase reaction of vinylidene fluoride with OH. [3] The global and yearly averaged 

lifetime of vinylidene fluoride was calculated as 4 days. Quantitative infrared crosssections of vinylidene fluoride were obtained at 298 K in the region 500-4000 cm-1

, and 

radiative forcing calculations were performed using the approximation method developed 

by Pinnock et al. [4] A GWP of 0.9 relative to CO2 with a 100-year integration time 

horizon was established. 

The methods used in determining this GWP value are essentially identical to those used 

for the values obtained for the gases listed in Table A-1: (1) the kinetic rate constants for 
reaction with critical atmospheric oxidants were measured and an atmospheric lifetime 

was determined; (2) the infrared absorption spectrum of the substance was measured; and 

(3) the atmospheric lifetime and infrared absorption spectrum were incorporated into a 

radiative transfer model to estimate the contribution of the substance to greenhouse 

forcing. 

Based on this publication in the peer-reviewed literature, DuPont requests that a 

provisional GWP of 0.9 be assigned for vinylidene fluoride.

1. "Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated 

GHGs; Final Rule", Federal Register 75:230 (December 1, 2010) p.74774.

2. "Table A-1 to Subpart A of Part 98—Global Warming Potentials": Table A-1 in 

40 CFR part 98, subpart A.

3. Baasandorj, M., et al., Rate Coefficients for the Gas-Phase Reaction of the 

Hydroxyl Radical with CH2═CHF and CH2═CF2. The Journal of Physical 

Chemistry A, 2010. 114(13): p. 4619-4633.

4. Pinnock, S., et al., Radiative forcing of climate by hydrochlorofluorocarbons and 

hydrofluorocarbons. Journal of Geophysical Research, 1995. 100(D11): p. 23227-

23238.