Toxic hazards of ammonia release and population vulnerability assessment using geographical information system.

Today, chemical industries manufacture, store and transport evermore hazardous substances and hence the risk of accidental releases of these chemicals can become more and more catastrophic in the context of increasing population and their requirements. The damage potential is proportional to the population characteristics of the location as well as various meteorological factors and geographical features. For the risk assessment of ammonia toxicity, the storage facility at Eloor industrial area is taken as a sample. Pollutant dispersion model - Areal Locations of Hazardous Atmosphere (ALOHA) is utilized to predict the toxicity impacted distance of ammonia. The model estimates the vulnerable areas, which may be affected toxically by an Ammonia release by integrating information about chemical properties of the substance, weather conditions prevalent in the area and release conditions. Risk assessment is done for four different atmospheric conditions, typical to the prevailing seasons and affected area is estimated in each scenario. To determine the affected population, the areal interpolation method in GIS database is also employed in this study, which illustrates the toxically impacted areas and the population in need of immediate help and evacuation. Such studies can serve as an effective tool for decision makers to prepare an emergency plan in case of accidental releases.