Volatile organic compounds near livestock farms and croplands: implications for secondary organic aerosol formation potential

Volatile organic compounds (VOCs) are key precursors of ozone and secondary organic aerosols (SOA), yet emissions from agricultural and livestock activities remain largely unrecognized in emission inventories. This study conducted field measurements of 34 VOC species near livestock facilities and adjacent croplands in Chuncheon, South Korea, during April, December, and February to characterize their composition, temporal variation, and secondary organic aerosol formation potential (SOAFP). Sum of the measured VOCs concentrations were highest in February, with alkanes comprising about 60% of the mass. However, aromatics—particularly multi-substituted compounds—dominated the SOAFP, contributing over 99% of the total. Distinct afternoon peaks (14:00–15:00) coincided with higher temperature, solar radiation, and facility operations such as feed handling and disinfection. The major SOA precursors were toluene and 1,2,3-trimethylbenzene in April, and BTEX compounds during the cold months. Despite their omission from South Korea’s official inventory, livestock-related VOCs were found to be chemically reactive and significant SOA precursors. These results highlight the need to include agricultural VOC emissions—especially aromatic species—into national emission inventories and control strategies to better predict and mitigate SOA formation in rural environments.