Supersonic transport SST

The following figures were obtained from a brochure produced by the Boeing Company. From these figures determine whether it would have been a good deal for the American taxpayer to support the building of the Supersonic Transport (SST) in the winter of 1971. What other factors should be considered ... 

This report deals primarily with the origins and effects of ozone and other photochemical oxidants. It is limited, more or less, to the problem of urban pollution and to such closely related topics as natural background in the earth s boundary layer. No consideration is given to the stratospheric ozone layer and the effects produced by supersonic transport (sst) emission or halocarbons. 

In 1971, Johnston suggested that anthropogenic emissions of NOx from a proposed fleet of supersonic transports (SSTs) could cause a reduction in ozone due to the set of chain reactions (10) and (11). At the time, a fleet of 500 SSTs flying seven hours a day in the stratosphere by 1985 was projected, and based on that, Johnston (1971) showed that the emissions would be expected to lead to significant ozone depletion. This was never realized because of the much smaller use of SSTs than projected. However, a subsequent proposal for the development of a high-speed civil transport (HSCT) raised some of the same issues, as discussed in the following section. 

Photochemical air pollution in the troposphere results from a complex interplay between sunlight and primary air pollutants emitted in ambient air that leads to the formation of ozone and other oxidizing and cye-irritaling agents. On the other hand, pollutants injected into the stratosphere by such human activities as supersonic transports (SST s) and release ofchlorofiuoro-methancs in air by their use as aerosol propellants and refrigerants may eventually reduce the protective layer of ozone from harsh solar ultraviolet radiation. Although the full impact of injected air pollutants in the stratosphere is not apparent at present, various model calculations show conclusively that the continuous future release of chlorofluoromethanes and NO (NO and N02) would result in substantial reduction of ozone in the stratosphere. 

If hydrogen makes subsonic planes look good, its use in a future supersonic transport (SST) glows with economic promise and environmental health, although studies are still needed to determine whether and how increased water vapor (in itself harmless) might change weather dynamics in the high stratosphere. 

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