Dispersion Modeling of SO₂ and NO₂ Emissions Using AERMOD on Ambient Air Quality at Steam Power Plant PT.X in Southeast Sulawesi, Indonesia

This study aims to analyze SO2 and NO2 concentrations around the PT.X power plant through direct measurements, model their distribution patterns using AERMOD, and evaluate the model’s performance using RMSE, MBE, and R statistical tests. Monitoring was conducted at two monitoring points (PLTU PT.X Area and Nii Tanasa Village) over four 1-hour intervals (morning, afternoon, evening, night) using an Impinger Air Sampler. The results show that the highest field-measured SO2 (39.95 µg m⁻³) and NO2 (14.82 µg m⁻³) occurred during the afternoon, whereas AERMOD predicted peak concentrations at night, reaching SO2 (31.87 µg m⁻³) and NO2 (10.56 µg m⁻³) at the PLTU PT.X monitoring point, indicating stable atmospheric conditions. Pollutant distribution aligns with the prevailing north-northeast winds, with concentrations decreasing with distance and remaining within regulatory limits. Statistical validation for SO2 and NO2 yielded RMSE values of 14 µg m⁻³ and 5.37 µg m⁻³, MBE of -10.44 µg m⁻³ and -4.32 µg m⁻³, and R of 0.36 and 0.12, respectively. These values reflect the inherent challenges of aligning short-term field data with long-term dispersion modeling. It is concluded that spatial proximity to emission sources is the primary factor determining concentration patterns. While acknowledging temporal limitations for full-scale validation, the AERMOD model serves as a valuable preliminary screening tool for these distribution patterns. These findings provide an initial overview to inform decision-making and support the development of effective emission mitigation and environmental management strategies for the surrounding areas.