Estimation of Assimilative Capacity of the Airshed in Iron Ore Mining Region of Goa

The assimilative potential of the atmosphere entails the capacity of the atmosphere to accept and dissipate the pollutant discharge without exceeding the standard limits. The evaluation of assimilative potential is important because it is a useful tool for the area-based management of air pollution and to mitigate the pollution level. The assimilative potential of the atmosphere can be represented in two ways: one as the ventilation coefficient and the other as the dispersion potential of emission loads discharged into the region. The ventilation coefficient is directly proportional to the assimilation potential of the atmosphere and can be computed using meteorological parameters. In the second approach, the assimilative capacity can be estimated in terms of permissible emission load that is the difference between the permissible and the existing pollutant concentration levels. The existing concentration levels can either be monitored or predicted using an appropriate dispersion model. For this study the assimilated potential of the atmosphere was estimated in terms of potential pollution load by comparing the predicted concentration of PM10 at 14 discrete receptor points using the American Meteorological Society EPA Regulatory Model (AERMOD) dispersion model. The investigation clearly inferred that, the area under consideration has a fair assimilative capacity.