Seasonal Measurement of Ammonia Concentration and its Relationship with Ammonium in the Field Areas of Jeollabuk-do

This study investigated the relationships between secondary inorganic aerosols in PM2.5 and precursor gases emitted from active agricultural areas over a period of one year, from June 1, 2022, to May 31, 2023, in Rice (Buan) and Fields (Gochang) in the Jeollabukdo Region simultaneously. In addition, the study examined the particle-phase conversion rates of gaseous precursor compounds to elucidate factors influencing the chemical characteristics of PM2.5. The high NH3 concentration in the early morning, assuming constant soil emission, suggested a significant influence from surrounding environmental conditions. In Buan and Gochang, NO3- predominantly existed in particle form during cold winter temperatures, while in hot summer temperatures, it mainly existed in the gas phase, demonstrating distinct seasonal behavior. Furthermore, NO3- was influenced by localized generation due to regional primary emissions. The study results indicate that the formation of NO3- in Buan and Gochang is primarily governed by NH4+ originating from regional soil-emitted NH3. These findings can serve as crucial foundational data for elucidating the seasonal concentrations of precursor gases, including NH3, emitted to agricultural regions.