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

Abstract

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/m³) and NO₂ (14.82 μg/m³) occurred during the
day, whereas AERMOD predicted peak concentrations at night, reaching SO₂ (31.87 μg/m³) and NO₂ (10.56 μg/m³)
at the PLTU PT.X monitoring point, indicating stable atmospheric conditions. Pollutant distribution aligns with the
prevailing north-northeast winds, with concentrations decreasing significantly by distance and remaining within
regulatory limits. Statistical validation for SO₂ and NO₂ yielded RMSE values of 14 μg/m³ and 5.37 μg/m³, MBE
of -10.44 μg/m³ and -4.32 μg/m³, 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.