Organic dust exposures from work in dairy barns

Area of Science:

• Environmental science
• Occupational health
• Industrial hygiene

Background:

• Dairy barns contain complex mixtures of airborne organic dusts.
• Routine barn work can lead to significant worker exposure to these dusts and their constituents.
• Potential respiratory health effects from these exposures are a concern.

Purpose of the Study:

• To characterize airborne exposures to organic dusts and their constituents in Wisconsin dairy barns.
• To quantify levels of specific analytes including endotoxins, antigens, and irritant gases.
• To assess potential respiratory exposure hazards for workers.

Main Methods:

• Environmental surveys conducted in 85 predominantly dairy barns.
• Measurement of airborne dusts (total, inhalable, respirable), particle size, endotoxins, microbial counts, histamine, antigens, ammonia, CO2, and H2S.
• Analysis of correlations between dust concentrations and constituents.

Main Results:

• Geometric mean concentrations for total, inhalable, and respirable dusts were 0.74, 1.78, and 0.07 mg/m3, respectively.
• Endotoxin levels ranged from 25.4 to 34,800 EU/m3, with a geometric mean of 647 EU/m3, exceeding respiratory health thresholds.
• Ammonia was frequently detected; correlations between dusts and constituents were present but generally weak.

Conclusions:

• Dairy barn environments present complex organic dust exposures with quantifiable levels of toxic and immunogenic constituents.
• Endotoxin and ammonia exposures represent significant potential respiratory hazards for dairy workers.
• Further research into mitigating these occupational exposures is warranted.