INTERACTION OF COMBUSTION WITH THE ATMOSPHERE

摘要

The goal of this paper is to provide the combustion community with some chemical insight into why control of effluents from combustion processes is important. An overview of atmospheric chemistry in the troposphere and stratosphere is presented with emphasis on anthropogenic effects. These effects have large contributions from applications of combustion of fossil fuels. An overview of the makeup of atmospheric regions and some of the background chemistry is followed by consideration of the chemical consequences of release to the atmosphere of chemicals related to combustion processes. A chemical mechanistic explanation for specific atmospheric effects is discussed. These include: photochemical smog―an urban effect; acid rain―a regional problem; stratospheric ozone depletion―a global problem; polar ozone depletion―a corollary to global depletion; and possible climate change―an effect whose dimensions are still being questioned. The chemistry of the "clean" troposphere is a balance between the production and loss of ozone in the process of oxidizing CO to CO_2. The balance is controlled by the NO_x concentration. The addition of hydrocarbons into urban atmospheres starts a chemical process that resembles low-temperature, photo-chemically driven combustion. Stratospheric ozone depletion is discussed in terms of the chemistry of HO, NO, and Cl, all of which take part in chain processes that catalyze the ozone destruction process represented by the reaction: O + O_3→ 2O_2. The effects of reactions on particulates manifesting in phenomena such as the "antarctic ozone hole" are detailed. The "natural greenhouse effect" is discussed, and the potential for anthropogenic enhancement is considered.