Systematic Review of Sulfur Oxides Levels in Industrial and Urban Settings in Iran

Abstract

The Sulfur dioxide (SO2) is a prevalent pollutant in urban atmospheres. At a concentration level exceeding 9 ppm, it emits a potent and unpleasant odor and can prove fatal. The most harmful effects of air pollution are often due to a combination of sulfur oxides, particulate matter, and humidity. Given the importance of this pollutant in determining overall air quality, an investigation into its presence in Iranian cities can offer significant insights into the distribution patterns and influencing factors of its concentration levels. Such knowledge is crucial for improving our understanding of air quality and devising effective management strategies. This research was conducted through a systematic review of three databases: Magiran, SID, and Google Scholar. The review focused on articles reporting on the concentration of SO2. A total of 123 articles relevant to the study were initially identified. After a thorough examination, duplicate and irrelevant articles were excluded, leaving 25 articles that fulfilled the inclusion criteria. The analysis shows that the average concentration of SO2 in industrial areas (226.1 ± 218.2 µg/m³) is significantly higher than that in urban areas (92.6 ± 125.4 µg/m³). Furthermore, the concentration of SO2 in outdoor environments (144.2 ± 178.9 µg/m³) exceeds that in indoor environments (74.9 ± 66.9 µg/m³). Notably, the concentration of SOx in central urban areas **surpasses** that in peripheral areas, with an average value of (190.1 ± 144.1µg/m³). The study also found that these concentrations are considerably higher during the summer months, averaging (224 ± 334 µg/m³). The results demonstrate that the levels of sulfur oxides, particularly in industrial settings, are elevated during the warmer seasons in comparison to other periods.