Present and future trends in the atmospheric burden of ozone-depleting halogens

摘要: The burden of ozone-depleting chemicals in the lower atmosphere has been decreasing since 1994 as a result Montreal Protocol1,3. Here we show how individual have influenced this decline, order to estimate could change near future. Our measurements atmospheric concentrations persistent, anthropogenic that account for most halogens today's stratosphere decline stems predominantly from decrease load trichloroethane (CH3CCl3), previously common cleaning solvent. influence chemical on now peaked, however, and will become much smaller over next five ten years. As lessens, theburden halogen be sustained only if emissions other halocarbons fall. Although gases regulated by Protocol decreased substantially past years (refs 4), potent gas CBrClF2 (halon-1211) remained fairly constant during period12,29, despite stringent limits production developed countries 1994. consequent accumulation halon is retarding more than any persistent gas.