ATMOSPHERIC LIFETIMES AND OZONE DEPLETION POTENTIALS OF METHYL-BROMIDE (CH3BR) AND DIBROMOMETHANE (CH2BR2)

The rate coefficients for the reactions of OH radical with CH3Br and CH2Br2 were measured as functions of temperature using the laser photolysis - laser induced fluorescence method. This data was incorporated into a semi-empirical model [Solomon et al., 1992] and a 2-D model to calculate the steady - state Ozone Depletion Potentials (ODP) and atmospheric lifetimes, tau, with greatly improved accuracy as compared to earlier studies. The calculated ODPs and tau are 0.65 and 1.7 years and 0.17 and 0.41 years for CH3Br and CH2Br2, respectively, using the semi-empirical model. These lifetimes agree well with those calculated using a 2-D model. This study better quantifies the ODPs and tau of these species which are needed inputs for discussion of possible regulation of human emissions currently under international considerations.