depletion of ozone layer

             and monatomic oxygen into molecular oxygen (O2).
             In volcanic eruptions, the sulfate aerosols released are a .
             natural cause of ozone depletion. The hydrolysis of N2O5 on .
             sulfate aerosols, coupled with the reaction with chlorine in HCl, .
             ClO, ClONO2 and bromine compounds, causes the breakdown of ozone. .
             The sulfate aerosols cause chemical reactions in addition to .
             chlorine and bromine reactions on stratospheric clouds that .
             destroy the ozone.8.
             Some ozone depletion is due to volcanic eruptions. Analysis .
             of the El Chichon volcanic eruption in 1983 found ozone .
             destruction in areas of higher aerosol concentration (Hofmann and .
             Solomon, "Ozone Destruction through Heterogeneous Chemistry .
             Following the Eruption of El Chichon"). They deduced that the .
             "aerosol particles act as a base for multiphase reactions leading .
             to ozone loss."9 Chlorine and bromine cooperates with .
             stratospheric particles such as ice, nitrate, and sulfate to .
             speed the reaction. Sulfuric acid produced by eruptions enhances .
             the destructiveness of the chlorine chemicals that attack ozone. .
             Volcanically perturbed conditions increase chlorine's breakdown .
             of ozone. Also, chlorine and bromine react well under cold .
             temperatures 15-20 kilometers up in the stratosphere where mos.
             of the ozone is lost. This helps explain why there is less ozone .
             in the Antarctic and Arctic polar regions.10, 11.
             The Antarctic ozone hole is the largest. A 1985 study .
             reported the loss of large amounts of ozone over Halley Bay, .
             Antarctica. The suspected cause was the catalytic cycles .
             involving chlorine and nitrogen.12.
             Halons, an especially potent source of ozone depleting .
             molecules, are used in fire extinguishers, refrigerants, chemical .
             processing. They are composed of bromine, chlorine, and carbon. .
             Most of the bromine in the atmosphere originally came from .
             halons. Bromine is estimated to be 50 times more effective than .
             chlorine in destroying ozone.13 .
             Insect fumigation, burning biomass, and gasoline usage all .