The Stratospheric Photochemistry of Chlorine Compounds and Its Influence on the Ozone Layer
Most gaseous chemical species released at the surface of the earth are removed from the atmosphere rather rapidly, and consequently are not important as stratospheric pollutants. Among the effective tropospheric removal processes or sinks are rainout and washout, especially for water-soluble species; biological interactions; and decomposition by absorption of visible (400–700 nm) or near ultraviolet (300–400 nm) solar radiation. Chemical reaction, either with surface materials or with common tropospheric gaseous species (for example OH radicals), can also be very effective in other cases. However, whenever a molecular species is reasonably inert toward these tropospheric interactions, the molecules can survive long enough to penetrate into the stratosphere and become potential stratospheric pollutants. As such molecules rise higher and higher into the stratosphere, they become exposed to shorter and shorter wavelengths of ultraviolet light, and eventually, at high enough altitudes, all diatomic or polyatomic molecules can be photochemically decomposed by intense solar ultraviolet radiation.
KeywordsMercury Foam Ozone Catalysis Chlorine
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