Development of the area-based assimilative capacity for sustainability management of air toxic emission from petroleum and petrochemical industrial complex

This study explored benzene and 1,3-butadiene emissions from a petroleum and petrochemical industrial estate in Rayong, Thailand, using a comprehensive, multi-step approach. The research combined detailed emission inventories, air dispersion modeling with AERMOD which is appropriate for assessing primary, non-reactive pollutants at near-field distances from industrial sources, and evaluations of the area's capacity to absorb pollutants. The objective was to identify emission patterns, assess environmental impacts, and pinpoint the main sources influencing pollutant levels. Results showed that storage tanks were the primary driver of benzene emissions (54%) and wastewater treatment systems were the main source of 1,3-butadiene emissions (63%), with source analysis confirming that benzene levels were dominated by storage tanks while 1,3-butadiene concentrations were closely tied to wastewater treatment facilities. Although most predicted ground-level concentrations complied with national ambient air quality standards, elevated levels were detected near emission sources. The assimilative capacity assessment indicated that most monitoring sites could accommodate additional emissions without exceeding regulatory limits; however, one site located beside a busy road showed a negative capacity for both pollutants, highlighting the significant impact of vehicle emissions in areas with dense industrial and traffic activities. By integrating emission inventories, dispersion modeling, and environmental thresholds, this study offers valuable insights relevant locally and transferable to other industrial regions. It stresses the importance of emission control strategies targeting both industrial processes and traffic sources. The combined methodology provides practical guidance for environmental planners and policymakers seeking to implement effective, site-specific air quality management aligned with sustainable development goals. • Storage tanks and wastewater treatment systems were identified as the primary sources of benzene and 1,3-butadiene emissions. • AERMOD modeling showed VOC hotspots near industries, exposing nearby communities despite overall regulatory compliance. • Traffic emissions alone exceeded limits at one site, emphasizing the need to control vehicular pollution.