In this study, the ambient concentrations of volatile organic compounds (VOCs) were intensively measured from January 2012 to December 2016 using an evacuated canister and were analyzed using a gas chromatography/mass spectrophotometer (GC/MS) based on the US EPA TO-15 in the community and industrial areas of the largest petroleum refinery and petrochemical industrial complex in Map Ta Phut Thailand. The ternary diagram was used to identify the source of VOCs. Reactivity of VOCs on their ozone formation potential (OFP) were quantified by the maximum incremental reactivity coefficient method (MIR) and propylene-equivalent concentration methods. Results from the study revealed that aromatic hydrocarbon was the dominant group of VOCs greatly contributing to the total concentration of measured VOCs. Among the measured VOCs species, toluene had the highest concentration and contributed as the major precursor to ozone formation. The ternary analysis of benzene:toluene:ethybenzene ratios indicated that VOCs mainly originated from mobile sources and industrial processes. Within the industrial area, measured VOC concentration was dominated by halogenated hydrocarbons, and alkene was the highest contributor to ozone formation. The propylene-equivalent concentration method was also used to evaluate the reactivity of VOCs and their role in ozone formation, and secondly to support findings from the MIR method.

Automotive manufacturing is one of the potential sources of air pollution particularly involving volatile organic compounds (VOCs). This study intensively evaluated VOC emissions and their dispersion from the industry. The measured VOCs were speciated for further evaluation of their odor threats according to the characteristics of each compound. Mathematical emission and air dispersion models were applied to assist in elaborating the source–receptor relationship allowing the determining of existing business-as-usual conditions with proposed mitigation measures to manage the pollution of the factory studied in this paper. Seven VOC species potentially caused odor problems to the surrounding community, including 1-butanol, ethyl benzene, toluene, m,p xylene, o xylene, methyl ethyl ketone, and methyl isobutyl ketone. The results from the AERMOD dispersion model revealed that the smell from these chemicals could reach up to about 800 m from the source. Analysis of mitigation measures indicated that two interesting scenarios should be considered according to their effectiveness. The concentrations of VOCs can decrease by up to 4.7, 14.0 and 24.9% from increasing the physical stack height by +1, +3 and +5 m from its existing height, respectively. Modification of the aeration tank of the wastewater treatment unit to a closed system also helped to reduce about 27.8% of emissions resulting in about a 27.6% decreased ambient air concentration. This study provided useful information on the characteristics of VOCs emitted by the automobile manufacturing industry. It also demonstrated the relevant procedures and highlights the necessity to comprehensively analyze the source–receptor relationship to evaluate the most appropriate measures in managing industrial air pollution.

The automotive industry is a significant source of volatile organic compound (VOC) emissions, particularly from solvent-based painting processes. This study evaluated VOC characteristics and distribution to assess associated health risks for workers and communities at varying distances from automotive painting facilities in Thailand, focusing on stacks and wastewater treatment plants that handle solvent-containing wastewater. The findings revealed aromatic compounds were predominant (66% of the total emissions), followed by oxygenated VOCs (26%). The stacks mainly emitted aromatics such as toluene and ethylbenzene, whereas the wastewater released oxygenated VOCs, particularly methyl isobutyl ketone and methyl ethyl ketone. The exposure concentrations in each area were primarily influenced by wind direction, with higher levels observed by downwind. The hazard index for areas was less than 1, indicating safe noncarcinogenic risk levels. The lifetime cancer risk showed that ethylbenzene posed a probable risk in all areas (maximum 8.15 × 10⁻⁶ μg/m³), whereas 1,2-dichloroethane exhibited a probable risk within 200 meters of the facility (maximum 4.13 × 10⁻⁵ μg/m³). This study supports the development of comprehensive emission standards covering health-related compounds and guides residential planning to avoid potential health impacts.