Volcanic Contribution of Chlorine to the Stratosphere: More Significant to Ozone Than Previously Estimated?

Abstract

Earlier estimates of the chlorine emission from volcanoes, based upon evaluations of the preeruption magmatic chlorine content, are too low for some explosive volcanoes by a factor of 20 to 40 or more. Degassing of ash erupted during 1976 by Augustine Volcano in Alaska released 525 x 10⁶ kilograms of chlorine (± 40 percent), of which 82 x 10⁶ to 175 x 10⁶ kilograms may have been ejected into the stratosphere as hydrogen chloride. This stratospheric contribution is equivalent to 17 to 36 percent of the 1975 world industrial production of chlorine in fluorocarbons.