Evaluation of the atmospheric lifetime and radiative forcing on climate for 1,2,2,2-Tetrafluoroethyl Trifluoromethyl Ether (CF3OCHFCF3)

The compound 1,2,2,2-Tetrafluoroethyl Trifluoromethyl Ether, CF3OCHFCF3 (HF E-227), is currently being considered as a potential replacement for certai n halocarbons, particularly for perfluorocarbons (PFCs), as a dry etching g as in the semiconductor industry. For this reason, it is important to deter mine the potential environmental effects resulting from the use and emissio ns of this compound. In this paper, the atmospheric lifetime, radiative for cing, and Global Warming Potentials (GWPs), an important measure of the pot ential effects of a gas on climate, are evaluated for this compound using o ur zonally averaged chemical transport and radiative transfer models of the atmosphere. To our knowledge, this is the first time this compound has bee n evaluated with such atmospheric models. In order to calculate the lifetim e and radiative forcing, the rate constants and infrared cross sections of this compound were measured in laboratories at Illinois and Purdue, and res ults are reported here. The model-evaluated atmospheric lifetime is 11.3 ye ars, mainly due to reaction with OH radicals. The model-evaluated instantan eous-clear-sky radiative forcing is 0.38 W m(-2) ppbv(-1), about 45% lower than previously estimated [Imasu et al., 1995]. However, the model-estimate d cloudy-sky adjusted forcing, needed to calculated GWPs, is about 25% lowe r than the model-estimated instantaneous-clear-sky forcing. The GWPs are ca lculated to be 3400, 1200, and 370 for 20, 100, and 500 year time horizons, respectively.