Sulfuric odorous compounds emitted from pig-feeding operations

The objective of the study was to quantify the concentration and emission levels of sulfuric odorous compounds emitted from pig-feeding operations. Five types of pig-housing rooms were studied: gestation, farrowing, nursery, growing and fattening rooms. The concentration range of sulfuric odorous compounds in these pig-housing rooms were 30-200 ppb for hydrogen sulfide (H₂S), 2.5-20 ppb for methyl mercaptan (CH₃SH), 1.5-12 ppb for dimethyl sulfide (DMS; CH₃SCH₃) and 0.5-7 ppb for dimethyl disulfide (DMDS; CH₃S₂CH₃), respectively. The emission rates of H₂S, CH₃SH, DMS and DMDS were estimated by multiplying the average concentration (mg m^-3) measured near the air outlet by the mean ventilation rate (m³ h^-1) and expressed either per area (mg m^-2 h^-1) or animal unit (AU; liveweight of the pig, 500 kg) (mg pig^-1 h^-1). As a result, the emission rates of H₂S, CH₃SH, DMS and DMDS in the pig-housing rooms were 14-64, 0.8-7.3, 0.4-3.4 and 0.2-1.9 mg m^-2 h^-1, respectively, based on pig's activity space and 310-723, 18-80, 9-39 and 5-22 mg AU^-1 h^-1, respectively, based on pig's liveweight, which indicates that their emission rates were similar, whether based upon the pig's activity space or liveweight. In conclusion, the concentrations and emission rates of H₂S were highest in the fattening room followed by the growing, nursery, farrowing and gestation rooms whereas those of CH₃SH, DMS and DMDS concentrations were largest in the growing room followed by the nursery, gestation and farrowing rooms.