We estimate the total concentration [ClX> versus altitude of Cl-containing molecules, principally, HCl, Cl and Cl0. The predicted present stratospheric concentrations appear to be due to photolysis near 30 km of man-made CF2Cl2 and CFCl3, and CCl4 from a ground-level source, man-made or natural. Based on preliminary measurements of CH3Cl at ground we estimate its contribution to stratospheric ClX through the major known loss mechanism for CH3Cl, abstraction by OH. Ground-level sources of HCl and Cl2 are large but tropospheric processes preclude significant impact on the stratosphere. Our computed profiles are consistent with first HCl concentrations measured by Lazrus et al. [1974, 1975> in the 15-27 km region. |