| Summary: | Automotive generated ice fog is a form of air pollution that results when exhaust water vapor freezes into minute particles which form a dense fog. The major control technique evaluated was cooling the exhaust gases to well below the dew point, thus condensing water vapor into a liquid stream before final discharge. During the winters of 1974-75 and 1975-76 the Arctic Environmental Research Station evaluated 12 cooler-condensers on nine inservice vehicles. It was found that ice film formation decreased heat transfer efficiency. An ice fog mass emission reduction up to 80 percent was attained with cooler-condensers on motor vehicles. However, the increase in visibility over roads was not proportional because of the many other ice fog sources. The overall impact of automotive ice fog control would be a visibility increase of at least 70 percent in areas where motor vehicles create 50 percent or more of the ice fog. Control of automobile-generated ice fog would also mean cleaner air, but perhaps more ice on the road. Cleaner air would result because sulfur oxides and lead compounds would be absorbed in the condensate. This condensate, if allowed to drip from the cooler-condensers, would freeze onto the road and require a more intense snow removal effort.
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