Pulmonary function and airway inflammation among dairy parlor workers after exposure to inhalable aerosols

Background: Inhalation exposure to organic dust causes lung inflammation among agricultural workers. Due to changes in production and work organization, task-based inhalation exposure data, including novel lung inflammation biomarkers, will inform exposure recommendations for dairy farm workers. Methods: Linear regression was used to estimate the associations of airborne exposure to dust concentration, endotoxin, and muramic acid with pulmonary outcomes (i.e., FEV₁, exhaled nitric oxide). Logistic regression was used to estimate associations with self-reported pulmonary symptoms. Results: Mean exposure concentration to inhalable dust, endotoxin, and muramic acid were 0.55 mg/m³, 118 EU/m³, and 3.6 mg/m³, respectively. We found cross-shift differences for exhaled nitric oxide (P = 0.005) and self-reported pulmonary symptoms (P = 0.008) but no association of exposure with respiratory outcomes. Conclusions: Inhalation exposures during parlor tasks, which were lower than previously reported and were not associated with cross-shift measures of pulmonary health among dairy workers. Modern milking parlor designs may be contributing to lower inhalation exposure. Am. J. Ind. Med. 60:255–263, 2017.