Similar exposure group (task) based analysis of bioaerosol exposures in dairies

Objectives: The objective of this research was to evaluate variability in bioaerosol exposures among similar exposure groups (SEGs) based on dairy workers’ tasks. This analysis is an important step in a broader effort to develop effective interventions to reduce exposures and health effects. Methods: Bioaerosol samples were collected in workers’ breathing zones (n=116) over entire work shifts (10 – 12 hours) using Button samplers (inhalable) with PVC filters to measure organic dust, endotoxin (recombinant Factor C assay), and 3-hydroxy fatty acids (3-OHFA), ergosterol and muramic acid (GC/MSMS). Ammonia was measured using direct-reading ToxiRae samplers. To our knowledge this is the first study to include combined analysis of 3- OHFA, muramic acid and ergosterol in dairy operations. Results: SEGs were defined based on work tasks including: milking (30% of population), breeding (3%), birthing/rearing (9%), medical care (12%), feeding (4%), moving stock (4%), rebedding stalls (9%), milking parlor maintenance (3%), facility maintenance/repairs (2%), other tasks [administration] (6%) and mixed [two or more tasks] (18%). Participants were predominantly male (88%), Hispanics (91%), 25 to 40 years old. Exposures to endotoxin (p