Health risk assessment and Sobol' sensitivity analysis of power plant air pollution (SO2 and NOX): the effect of power plant fuel change.

Abstract

This study aimed to evaluate the concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOX) around the Qom (a province in Iran) combined cycle power plant in relation to seasonal variations and fuel type from December 2014 to May 2015. Passive sampling was used in three monitoring sites around the power plant to assess noncarcinogenic health risks associated with exposure to SO2 and NOX. Results showed the higher concentrations of NOX and SO2 in winter than in spring. The highest concentrations of NOX in winter (when power plants used gasoil) and spring (when power plants used gas fuel) were 52.70 ± 21.70/52.70 ± 13.20 and 22.10 ± 7.00 µg/m3. Similarly, the highest concentrations of SO2 in winter and spring were 5.00 ± 0.20 and 3.90 ± 0.70 µg/m3. There was a moderately significant correlation between NOx and SO2 concentrations when the power plant consumed gasoil (Spearman rho coefficient, 0.68, p < .05). A significant difference was observed between gas concentration and fuel type (p < .05). The hazard quotient values for SO2 exposure were below 1 for all age groups, whereas those for NOx were above 1 for infants and children. The hazard index for NOX was above 1, indicating an unacceptable risk to human health. Sobol' sensitivity analysis identified the inhalation rate and NOX concentration as the most significant factors determining the noncarcinogenic risks across age groups. In conclusion, the use of gasoil by power plants increases the emission of pollutants, thereby raising the health risks for residents in these regions, particularly vulnerable demographics like children. Therefore, prioritizing air quality management such as using cleaner fuels and emission control technologies in power plants as well as continuous air quality monitoring are of utmost importance.