Temporal distribution characteristics of odorous compounds in swine houses of South Korea

Currently odor problems caused by animal feeding operation play a role in provoking environmental civil petition. The objectives of this study were to investigate the monthly distribution characteristics of 22 offensive odor compounds in swine houses, which are under regulation in Korea, and to compare their levels according to ventilation type and manure treatment mode. During the 1 year survey between July 2021 and June 2022, air samples were collected. In this study, ammonia was observed at the highest levels (the annual mean, 13.9 × 10³ ppb) among other offensive odorous compound regardless of the types of swine house and seasons, followed by fatty acids (139.9 ppb), sulfuric odorous compounds (52.3 ppb), volatile organic compounds (27.5 ppb), and trimethyl amine (24.5 ppb). Furthermore, hydrogen sulfide among sulfur compounds, methyl ethyl ketone among volatile organic compounds, and propionic acid and n-butylic acid among fatty acids were observed to the highest level of several hundreds of ppb. In particular, five aldehydes (acetaldehyde, propionaldehyde, butyraldehyde, n-valeraldehyde, and i-valeraldehyde) among the 22 offensive odor-generating compounds were not detected in any season. The levels of odorous compounds were the highest in winter (Dec.–Feb.) and lowest in summer (June–Aug.). For comparison of overall distribution regarding concentrations of odorous compounds by ventilation type and manure removal mode, relatively lower concentrations were observed in swine houses with forced ventilation or with scrapper type. Our findings indicate that annual monitoring for these odorous compounds would be necessary for establishment of control strategy. Also, installation of active ventilation, as well as the increase of removal frequency of pig manure could contribute to lower concentrations of odorous compounds in swine buildings.