Characteristics and chemical composition of PM2.5 in agricultural regions: a case study in Jeonbuk-do, South Korea

Fine particulate matter (PM2.5) is a major air pollutant that significantly affects both human health and atmospheric chemistry. Although it has been extensively researched in urban and industrial areas, studies focusing on its characteristics in agricultural regions remain limited. This study aimed to analyze the chemical composition of PM2.5 in the agricultural areas of Jeonbuk-do, South Korea, and assess the seasonal variations in its components. Air quality monitoring stations were established in a paddy field (Buan) and an upland field (Gochang) from June 2022 to May 2024. Continuous measurements of PM2.5, PM10, and gaseous precursors such as NH3, NOx, and SO2 were performed, and the concentrations of organic carbon, elemental carbon, and major ions (Na+, NH4+, K+, Ca2+, Mg2+, Cl−, NO3−, SO42−) in PM2.5 were analyzed in PM2.5 were analyzed. Results indicated that ionic species were the dominant component, accounting for > 40% of the PM2.5 mass. SO42− and NO3− concentrations varied seasonally, with SO42− levels peaking in summer and NO3 − concentrations peaking in winter. NH4+ concentrations were consistently higher in the agricultural areas than in urban and industrial sites, highlighting the contribution of agricultural emissions. These findings underscore the necessity of dedicated air quality monitoring in agricultural regions to elucidate the mechanisms of PM2.5 formation and determine their implications for rural air quality management.