| Purpose. To measure the full workshift and activity-specific air contaminant exposures of specialty-area pig barn workers (Dry Sow/Breeding, Farrowing, and Nursery/Grower-Finisher).;Methods. From 20 large confinement pig barns throughout Alberta, Canada, which met inclusion criteria, 10 were randomly selected. Forty-three volunteer specialty workers (winter) and 37 (summer) were randomly recruited (16, 12, 15 in winter, and 13, 10 and 14 in summer, for Dry Sow/Breeding, Farrowing, and Nursery/Grower-Finisher workers, respectively). The mean age of study participants was 33.6 ± 9.5 years, and 64% were male. Personal air contaminant exposures were continuously monitored over three consecutive shifts using a custom-made, study-specific, Personal Environmental Sampling Backpack (PESB II) strapped to the worker's back. The PESB II was portable, met stringent biosecurity requirements dictated by the study barns a priori, and captured personal exposures to respirable dust, endotoxin, CO2, NH3, and H2S simultaneously in the worker's breathing zone. Investigators followed workers to record workplace tasks conducted.;Results. Over 25% of all specialty-area workers had respirable dust mass exposures exceeding a proposed guideline of 0.28 mg/m 3. Nursery/Grower-Finisher workers had the highest respirable dust mass and endotoxin exposures, compared to Farrowing workers, and the highest respirable dust count exposures during dry feeding and barn checking tasks. Farrowing workers were 3 times more likely to be exposed to high dust counts when conducting general workplace activities. There was a trend to higher respirable dust exposures during pig moving activities. Peak H2S exposures (≥15 ppm) occurred during pit work activities. Workers conducting these tasks were 21 times more likely to be exposed to H2S concentrations exceeding the Government of Alberta's proposed 15 ppm ceiling limit.;Conclusions. Personal monitoring allowed for the continuous capture of actual worker exposures throughout multiple areas of modern pig barns. Full workshift and activity-specific air contaminant exposures differed by specialty, indicating that pig barn workers should be enrolled in studies on the basis of area-specialty. The presence of solid flooring was found to be predictive of higher endotoxin and lower H2S exposures. Observer-recorded time activity diaries are essential to reliably and accurately link to real-time continuous workplace air contaminant exposures. |
