Identifying and Prioritizing the Factors Affecting Air Pollution in Tehran with an Interpretive Structural Modeling Approach

Air pollution is a crisis that many countries around the world are currently facing. The city of Tehran has been facing the problem of air pollution for a long time and its solution has become one of the important social demands and has found international dimensions. The phenomenon of air pollution in Tehran has been affecting Tehran for many years, and in the past several years, with the arrival of the cold and winter season, the residents of the capital face a serious problem, and despite all the measures taken to prevent pollution, we still see days when schools are closed and the plan of even and odd cars also continues; but pollution is strongly standing. The results of previous studies indicate the influence of various factors including geographical factors, natural features of the city, temperature inversion and industrial pollutants in air pollution.The purpose of this study is to provide a model for individuals with air pollution in Tehran.

The current research is applied in terms of the type and purpose of the research, and descriptive-analytical in terms of the data collection method. In this research, after identifying the factors affecting the air pollution of Tehran city, using the opinion of relevant experts, the researcher has used the interpretive structural modeling (ISM) technique to level and interpret the conceptual relationships of the mentioned indicators. By reviewing the research literature and taking the opinion of experts, the issue is identified in the form of six indicators (temperature inversion, geographical-climatic location, pollution of factories and refineries, low quality of vehicles and fuel consumption, low green space per capita, high population density of Tehran) Took; Then, a structured matrix questionnaire was developed to determine the interrelationships of these indicators. The data obtained from the questionnaire were analyzed using interpretive structural modeling and plotted on five levels in an interactive network.

The results of this research showed that both industrial factors and climatic factors can be effective on air pollution in Tehran. According to result of the modeling, "pollution of factories and refineries" index was at the highest level. Therefore, transferring factories in the city and preventing the construction of new factories in the city as a solution can help reduce air pollution in Tehran.

When a temperature inversion occurs, the air becomes stable and particles accumulate in the range of the inversion layer and increase the intensity of air pollution. Regarding the pollution of factories and refineries, most of the processes that produce air pollution in industries, after the heating process, are dedicated to the process of combining materials, and air pollutants in the form of smoke and suspended particles include the most cases. Also, the combustion process in the engine of old and low-quality cars is not done well, and this is the main reason for the production of carbon monoxide. Climate controls the pollution conditions of Tehran city through changing its elements such as temperature, precipitation, pressure and wind. Also, compared to the big cities of the world and their population, Tehran is ranked 120 to 130 in terms of size, but in terms of density per square kilometer, it is ranked between 25 and 30. This means that in this city, the population has accumulated more than the ecological capacity and urban area, which causes crises such as air pollution.