Accession Number : AD0786454

Title :   Air Pollution and Warm Fog Modification.

Descriptive Note : Environmental research papers,

Corporate Author : AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s) : Weinstein,Alan I.

Report Date : 25 JUN 1974

Pagination or Media Count : 17

Abstract : Through a series of simple calculations on monodispersed fogs, it is shown that atmospheric air pollutants in the form of cloud condensation nuclei (CCN) contribute to a lowering of the visibility and, thereby, seriously inhibit the visibility-improving capability of some evaporation techniques of warm fog modification. In extreme pollution, where the CCN counts are in excess of 1000/cc and the initial visibility is, therefore, very low, those techniques that only depress relative humidity a few percent, for example, hygroscopic particle seeding, could be rendered almost powerless in improving visibility to practically useful levels. Those fog dispersal techniques that of practical necessity generally depress the relative humidity by more than five % such as thermal fog dispersal, are not so seriously hampered by atmospheric pollutants. (Modified author abstract)

Descriptors :   *Condensation nuclei, *Air pollution, Drops, Hygroscopicity, Particles, Fog, Visibility, Evaporation, Particle size

Subject Categories : Atmospheric Physics
      Air Pollution and Control

Distribution Statement : APPROVED FOR PUBLIC RELEASE