GIS-Based Spatial Risk Zoning of Ambient Air Pollution Using the Air Pollution Standard Index (ISPU) Around the Celukan Bawang Coal-Fired Power Plant

Abstract

Air pollution emitted from coal-fired power plants may influence ambient air quality and its spatial distribution in surrounding residential areas. This study aimed to analyze the spatial distribution of ambient air pollutants using the Air Pollution Standard Index (ISPU) integrated with Geographic Information System (GIS) analysis around the Celukan Bawang Coal-Fired Power Plant, Bali, Indonesia. Ambient air quality measurements were conducted at 20 monitoring locations within a 1-km radius of the power plant for SO₂, NO₂, PM₂.₅, and PM₁₀. ISPU values were calculated following the Indonesian Ministry of Environment and Forestry Regulation No. 14 of 2020 and spatially interpolated using the Co-Kriging method in ArcGIS. The resulting spatial distribution maps were interpreted together with wind direction, wind speed, topography, and land-use characteristics. All measured pollutant concentrations complied with the Indonesian ambient air quality standards, and the calculated ISPU values were predominantly classified as Good, with PM₂.₅ showing the highest relative ISPU values. Spatial analysis revealed relatively higher pollutant concentrations near the industrial complex and along the dominant wind pathway while remaining within acceptable air quality conditions. The integration of GIS, ISPU, and Co-Kriging provides a practical framework for visualizing spatial variations in ambient air quality and supports environmental monitoring, land-use planning, and evidence-based environmental management in industrial areas