On the formation of radiation fogs under heavily polluted conditions

[摘要] We have studied the effect of gaseous pollutants on fog droplet growthin heavily polluted air using a model that describes time-dependent sulfate production in the liquid phase and thermodynamical equilibrium betweenthe droplets and the gas phase. Our research indicates that the oxidation ofSO₂ to sulfate has a significant effect on fog droplet growth especially when hygroscopic trace gases,for example HNO₃ and NH₃ are present. The increased sulfate production by dissolution of hygroscopicgases results from increased pH (caused by absorption of ammonia) and from the increased size of the fog/smog droplets. Our resultsindicate that unactivated fogs may become optically very thick when the droplet concentrations are on the order of several thousand percubic centimeter of air.

[学科分类] 大气科学