ATMOSPHERIC FATE OF CF3OH .2. HETEROGENEOUS REACTION

The heterogeneous reactions of CF3OH with bulk liquid water and sulfur ic acid solutions were studied in wetted-wall flow reactors with chemi cal ionization detection of CF3OH. Heterogeneous reaction probabilitie s (gamma) increase strongly with increasing activity of water (e.g., g amma = 4 x 10(-4) On 60 wt% H2SO4 at 206 K and 8 x 10(-2) on 40 wt% at 211 K). The heterogeneous loss of CF3OH was also studied on submicron sulfuric acid aerosol in an atmospheric pressure laminar flow reactor . The aerosol reaction probabilities increase linearly with increasing particle radius (r < 0.5 mu m, 40 and 50 wt% sulfuric acid at 250 K), suggesting that CF3OH uptake is volume limited for stratospheric aero sol. These measurements indicate that CF3OH will have a lifetime of a few days in the troposphere due to its loss on cloud particles, but a much longer lifetime with respect to heterogeneous loss in the stratos phere.