Characteristics of hydrogen sulphide concentrations in mechanically ventilated swine buildings

摘要

Hydrogen sulphide (H_2S) concentrations in two mechanically ventilated swine buildings (3B and 4B) were continuously measured with fluorescence-based analyzers for six months. Air containing H_2S was automatically sampled 24 and 16 times daily from three locations: pit headspaces, pit ventilation fans, and wall ventilation fans, A total of 219 d of complete and validated data were selected to study temporal and spatial variations of H_2S concentrations in the buildings. Average daily mean H_2S concentrations were 180+-16 (mean +- 2 standard errors of the mean) and 232+-39 ppb in buildings 3B and 4B, respectively. Seasonal variations occurred as daily mean concentrations ranged from 18 to 1107 ppb. Expected saddle-shaped seasonal patterns from Aprilto September, inversely correlated to the ventilation pattern, were observed. Four distinct diurnal pattems of H_2S concentrations were also identified. The maximum, and minimum concentrations during fair weather occurred between 3:00-6:00 and 12:00-18:00, respectively. Spatial concentration variations were also observed as the daily mean concentration differences between any two sampling locations ranged from 2G+-6 to 132+-17 ppb.