Gas-Phase Tropospheric Chemistry of Organic Compounds
Gas-Phase Tropospheric Chemistry of Organic Compounds
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DOI：
10.1039/9781847552310-00065
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
R. Atkinson
中科院分区：
文献类型：
--
作者：
R. Atkinson
The troposphere is that region of the Earth’s atmosphere into which chemical compounds are generally emitted as a result of human activities (an exception being the exhaust from present and future supersonic transports). As described in the Sections below, the troposphere is a chemical ‘processor’resulting in the partial or complete degradation of almost all organic compounds emitted into the atmosphere, with the exception of the chlorofluorocarbons (CFCs) and several of the bromochlorofluorocarbons (Halons). The CFCs and Halons are therefore transported into the stratosphere and are photolysed by short-wavelength ultraviolet radiation as they rise through the stratospheric ozone layer, to produce C1’or Br’atoms which lead to depletion of stratospheric ozone through the C10,’and BrO,’catalytic cycles.’’2The focus of this chapter is on the gas-phase chemistry of volatile organic compounds in the troposphere. Organic compounds are expected to exist, at least partially, in the gas phase provided that they have liquid-phase (or sub-cooled liquid) vapour pressures of> Pa at the ambient atmospheric temperat~ re,~ and this demarkation between gas-phase and particle-associated organic compounds based on their liquid-phase vapour pressure can be used as a first approximation to assess the gas/particle distribution of chemicals in the atmosphere. No discussion is given here of the physical or chemical loss processes of particle-associated chemicals, gas-to-particle conversion, or dry and wet deposition of gas-phase organic compounds. Because of space limitations, the tropospheric chemistry of several important classes of organic compounds, including the hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs)[potential replacements for the CFCs], organosulfur compounds, and polycyclic aromatic hydrocarbons (PAH), is not dealt with here. The tropospheric chemistry of these compound classes has been discussed el~ ewhere, l.~-~ and
