Dispersion of NO2 pollutant in a gas refinery with AERMOD model: A case study in the Middle East

Introduction: Air pollution from industrial sources is a growing problem increasing the amount of air pollution by emitting various gaseous pollutants such as Nitrogen Oxides (NOx). This study analyzed Nitrogen dioxide (NO2) emissions using American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) from the stacks and flares of a gas refinery in the Middle East. Materials and methods: The NO2 emissions were measured from the stacks and flare of the refinery (231 samples). The distribution of emissions was investigated over a statistical period of 1 year for an average time of 1 h using the AERMOD dispersion model in an area of 25×25 km2. The predicted concentrations were compared with national and international standards and are plotted for the desired zones. Results: Comparison of simulation results with national and international clean air standards showed that NO2 emission modeled in all periods of 4 seasons is higher than the standard. Examination of NO2 emission and distribution maps also showed that the maximum concentration of NO2 pollutants occurred in the central parts and the area close to the refinery. The highest maximum concentration of 1-h NO2 was 3744.3716 μg/m3 in summer in the west and south of the refinery. Validation results also showed a high correlation between the predicted and actual results. Conclusion: The power of resources in emission and distribution, topographic conditions, and meteorological characteristics of the region are three important and influential factors in the distribution of NO2 pollutants. So pollution reduction strategies are needed due to the different types of use, surrounding residential areas, personnel, and people involved in the gas refining company.