Radiative effects of elevated pollutant layers

Abstract

A one-dimensional transport model was developed to study the effects of radiative participation of elevated pollutant layers. Special features of the model include a turbulent kinetic energy model and a two-stream solar radiation model. Pollutants were assumed to consist of aerosols and pollutant gases. Aerosols were allowed to scatter and absorb energy in the solar spectrum while pollutant gases were assumed to interact only with thermal radiation. The results of the simulations conducted with the model showed that elevated layers of pollutants could control mixed-layer expansion by modifying the stability of the capping stable layer. Cooling associated with gaseous pollutants generally helped the growth of the mixed layer, while solar heating induced by pollutants hindered mixed-layer growth by creating sharp inversions. By affecting mixed layer growth, radiative participation by pollutants also modified pollutant dispersal from the elevated pollutant layer. These results have important implications from the point of air pollution meteorology (especially fumigation) in which it is generally assumed that pollutants are passive.