Danger Assessment of Potential Resources of Air Pollution once Natural Disasters Occur

Abstract

Tehran with an area of 780 square kilometers and a population over 10 millions is one of the most polluted cities in the world. Concentration and accumulation of the industrial areas and their inappropriate location are the main reasons of pollution. While, concerning Tehran’s topographical and geological status and existence of many active faults, these areas can potentially be considered the main pollutant resources of air pollution once natural disasters occur. Therefore creating a suitable headstock for both optimized management to control air pollution and a management of crisis seems to be necessary.

An Optimum crises management needs identification of risky places before the crises happen. As forecasting and site selection are of the most important functions of Geospatial Information Systems (GIS), in this research GIS is used for modeling and estimation of risk rate. Also for assessment of collected data and classification of urban areas regard to risk rate, we used GIS technology which is able to analyze spatial and attribute data simultaneously.

The first step for this, is defining the risk parameters. In this research, three parameters are defined as main ones: nearness to faults, nearness to potential resources of air pollution and pollutant volume in these resources.

So at first, digital maps of Tehran faults was provided by GIS and saved as an input layer. But inventory of second and third parameters (nearness to potential resources of air pollution and pollutant volume in these resources) would need a time-consuming and costly field work.

For identifying the potential resources of air pollution, we had to gather statistics from industrial centers of Tehran such as chemical stores, fuel storages and position of these resources and volume of pollutants would help us in determining the remained two parameters. The position was determined by GPS and the volume of pollutants was recorded in designed forms.

While defining the combination model in GIS, the gain of emission factors of Inflammable materials was also used for more exact estimation of risk rate. Also for determination of distribution radius (determination of risk radius) and distance which is under effect of pollution, we used estimation of plum rise and meteorology. Using the Gaussian model is the basic of mathematics calculations. After determining the combination model, the model was introduced to software by using overlay functions in GIS environment. Hence, buffering analysis and overlaying of different risk layers were of the most important functions which we used in GIS section of this project.

Therefore, the risky areas around pollutant resources were identified concerning the pollutants’ volume. Then through a weighted overlay, different risk layers and buffers of Tehran’s faults, together with an estimation of probable pollution rates at the time of the incident were found.

On the basis of the conclusion of this research, not only a database for distribution status of potential resources of pollution was provided, but also it was possible for managers and plan designers to make and propose a monitoring plan and security decisions for identified resources.