Study of the Atmospheric Degradation, Radiative Forcing and Global Warming Potentials of CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH S. R. Sellevåg a, G. Myhre b, J. K. Sundet b and C. J. Nielsen a a Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway b Department of Geophysics, University of Oslo, P.O. Box 1022 Blindern, 0315 Oslo, Norway INTRODUCTION This work is a part of the project “Impact of Alternative Fluorinated Alcohols and Ethers on the Environment (IAFAEE)”, which is a co-operation between Uni- versity of Oslo, University College Dublin, University of Crete and Russian Academy of Science. We have studied the atmospheric degradation, radiative forcing and global warming potentials (GWP) of CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH, which have been suggested as new CFC and HCFC replacements. See also posters AP6 and AP12. RESULTS Rate Constants for the Reactions with OH Radicals Fig. 1. Loss of reactant versus reference in the reaction with OH. Table 1. Rate constants for the OH reactions with CH 2 FCH 2 OH, CHF 2 CH 2 OH, and CF 3 CH 2 OH at 298 K. Absorption Cross Sections Fig. 2. Absorption cross sections (base e) of pure vapors of CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH. Radiative Forcing and Global Warming Potentials Fig. 3. Zonal mean vertical distribution of CF 3 CH 2 OH given in ppt. The abundance decrease much faster with altitude than for well mixed greenhouse gases but to a smaller extent than for the two other compounds in this study. Fig. 4. Geographical distribution of radiative forcing due to CF 3 CH 2 OH. The glo- bal mean radiative forcing is 0.17 W m -2. Similar to the well mixed greenhouse gases the largest radiative forcing is in tropical regions with small cloud amounts, high surface temperature, and a large temperature difference between the surface and the tropopause. Table 2. Atmospheric lifetimes based on the OH reaction rate constants from this work. Table 3. GWP values relative to CO 2 and CFC-11 for three time horizons. CONCLUSIONS The impact of CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH on the Earth's radiative balance is negligible. With a lifetime of 71 days, however, a large part of CF 3 CH 2 OH will enter into droplets and end up as TFA. METHODS The relative rate measurements were performed in synthetic air at 1013  15 hPa and 298  2 K in a 250 L smog chamber with in situ FTIR detection. Hydroxyl radicals were generated by photolysis of ozone/water mixtures. Typical volume fractions were: 5-10 ppm of each organic compound and ca ppm of both water and ozone. The measurements of absolute integrated absorption intensities were carried out at 298  2 K using a Bruker IFS 113v spectrometer and DTGS detectors. A Ge/KBr beamsplitter was used in the MIR region, while 3.5 μm Mylar film was used in the FIR region. Single channel spectra of pure vapours were recorded in the region cm -1 with 1.0 cm -1 resolution and adding 512 scans. The pressures of the samples were in the range between 2 and 20 hPa, and were measured using a MKS Baratron Type 122A pressure gauge. The atmospheric distributions of CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH were cal- culated using the Oslo CTM2 model, which is an off-line chemical transport/tracer model. The model uses pre-calculated transport and physical fields to simulate chemical turnover and dist- ribution in the atmosphere. It is valid for the global troposphere and is three-dimensional with the model domain reaching from the ground up to 10 hPa (see e.g. ref. [4] for a further description). The radiative forcing calculations were carried out using a thermal infrared broad band model (details of the model are given in ref. [5]). CH 2 FCH 2 OH, CHF 2 CH 2 OH and CF 3 CH 2 OH were included with 5, 6 and 8 bands, respectively. [1] Kelly, T., Sidebottom, H., Unpublished. [2] Wallington, T.J., et al. (1988) J. Phys. Chem. 92, [3] Tokuhashi, K., et al. (1999) J. Phys. Chem. 103, [4] Acerboni, G., et al. (2001) Atmos. Environ. 35, [5] Myhre, G., Stordal, F. (1997) J. Geophys. Res. 102,