Evaluation of industrial air pollution contribution by type of industry in Pasir Gudang using AERMOD

In industrialized areas, air pollution is a recurring problem, especially in areas with high manufacturing and energy-intensive businesses. The challenge lies in the tension between industrial growth and environmental protection, as these sectors significantly contribute to pollution, resource depletion, and climate change. The objectives of the study were (1) to assess the contribution of each industrial group to the air quality in and around the Pasir Gudang industrial area, Malaysia, and (2) to evaluate the Air Pollution Index (API). Industrial emission sources were grouped into 10 specific groups, namely (1) biomass energy plants, (2) ceramic and mineral, (3) chemical, (4) electrical, (5) food and beverage, (6) metal industries, (7) paint, (8) rubber product, (9) waste recovery, and (10) wood respectively. For this, hourly, daily, and annual modelling of pollutant gases and particulate matter (SO₂, NO₂, and PM₁₀) for 3 years (2019 to 2021) were conducted using the AERMOD dispersion model. The maximum hourly, daily, and annual average ground level concentrations of SO₂ and PM₁₀ were mainly contributed by Wood industry group emissions, while NO₂ was dominated by metal industry group emissions. It was observed that the average hourly and daily NO₂ levels exceeded Malaysia's standard limits. The API during the study period was 146.97, contributed by NO₂, which indicates unhealthy conditions for sensitive groups. Therefore, NO₂ pollutant control measures from the Metal industry group should be prioritized in this industrial area.