Long-range transport of sulfur dioxide emissions from external sources to Tehran

Large-scale emissions of sulfur dioxide (SO2) from the combustion heavy fuel oils are deteriorating air quality in Tehran. Our analysis long-term SO2 emission data Tehran showed that magnitude local sources is inadequate to reach current levels. Bivariate polar plots, k-mean cluster, pairwise correlation, and potential source contribution function provided evidence impact large-scale transport external locations west/northwest, north/northeast, south/southwestern areas Further observations these hotspots were observed analyses conducted on TROPOMI satellite confirming significant consumption thermal power plants oil/gas refineries. These results also strongly agreed with NASA global catalog showing location major region. All approaches confirmed predominantly affected by regional further away located Iraq, Saudi Arabia, adjacent provinces neighboring Approximately 80% total concentration was have impacts outside While only contribute around 20% concentration.