Distribution of SO2 and NO2 Emissions 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 validate the model's accuracy using an RMSE statistical test. The first stage involved taking direct measurements at two monitoring points for 1 hour in four time intervals (morning, afternoon, evening, and night) using an Impinger Air Sampler. The second stage analyzed air dispersion modeling with AERMOD and compared direct measurements with model values using the RMSE statistic. The results show that the maximum concentration patterns from both monitoring points, the highest direct measurements of SO₂ (39.95 μg/m³) and NO₂ (14.82 μg/m³) occurred during the day, while the highest AERMOD predictions occurred at night, reaching SO₂ (385.78 μg/m³) and NO₂ (147.42 μg/m³) at the PLTU PT.X monitoring point. AERMOD's peak prediction at night indicates stable atmospheric conditions. The distribution pattern of pollutants aligns with the prevailing north-northeast wind direction, indicating that pollutant concentrations decrease significantly with distance and have little impact on surrounding residential areas. The RMSE test results for direct measurements and the AERMOD model in the morning, afternoon, evening, and night ranged from 0.99 to 11.79 μg/m³. It can be concluded that the spatial proximity of PLTU PT.X emission sources is the main factor determining the highest concentrations of SO₂ and NO₂, and that the validated AERMOD model has sufficient accuracy in predicting these distribution patterns. These findings provide a critical overview to inform decision-making and develop effective emission mitigation and environmental management strategies for the areas most affected by the power plant.