Manifesting the hidden pollutants: Quantifying emissions and environmental impact of petroleum refinery on PM2.5

This research thoroughly examined the emissions of primary fine particle and precursors of secondary particles (VOCs, SO2 and NOx) originating from the petroleum refinery operation. The central aim was to quantify the emission factors of fine particulate matter and analyze their spatial dispersion and source contributions, in order to evaluate their environmental impacts. The VOCs emission measurement appeared that the wastewater treatment plant unit was the most significant source of VOCs emissions, with pentane, cyclopentane, and propane being the dominant VOCs species released. The study employed the secondary organic aerosol potential (SOAP), sulfur oxidation ratio (SOR), and nitrogen oxidation ratio (NOR) methodologies to calculate the emissions of secondary PM2.5. The combustion stacks were the principal contributor to secondary PM2.5 emissions, with SO2 being the predominant secondary PM2.5 precursor species contributing to fine particulate matter, accounting for 82.5% of the total secondary PM2.5 emissions. The overall emission factor for the refinery was determined to be 0.31 g secondary PM2.5 per kg of refined crude oil. Furthermore, the analysis indicated that the combustion stacks were the primary contributors to PM2.5 concentrations at all receptor sites, accounting for 64.4%–80.8% of the total contribution, followed by the wastewater treatment unit and storage tanks. The study underscored the importance of focusing on secondary PM2.5 precursor emissions to effectively reduce emissions and environmental concentrations of PM2.5, highlighting the potential for more effective management and mitigation strategies targeting these precursors.