Dispersion of Air Pollutants in Low Wind Conditions at Hisar city

Dispersion of air pollutants in low wind condition assumes importance due to poor diffusion and transportation. To assess the atmospheric pollution potential with respect to SPM in low wind conditions, average meteorological data of 9 year (1990 to 1998) of Hisar city, India has been analyzed for four season's viz. winter, summer monsoon and post monsoon. It has been observed that the ground level concentration depends upon stability class, temperature and wind speed. In Hisar city, winter is the worst season, as the temperature inversions dominate during this season. However, the horizontal mixing and fog formation leading to the worst pollution condition in winter. On the other hand, in summer season dispersion of pollutants in Hisar city is excellent, as the higher plume rises result in the lower ground level concentration (GLC) at any given distance from the plume source.