Dose-response relationships between occupational aerosol exposures and cross-shift declines of lung function in poultry workers: Recommendations for exposure limits

Numerous articles have been published regarding the adverse respiratory hea lth consequences of working in intensive livestock and poultry housing. Thr eshold limit exposure guidelines are not currently applied to this environm ent, but they are essential to implement and monitor effective environmenta l controls. Previous dose-response research work with swine workers has res ulted in exposure limit recommendations of 2.5 mg/m(3) total dust, 0.23 mg/ m(3) respirable dust, 100 EU/m(3) endotoxin, and 7 ppm ammonia. No similar recommendations have been reported previously for poultry workers. Therefor e, an industry-wide study was conducted to examine dose-response relationsh ips of bioaerosol exposures and worker respiratory health. A total of 257 p oultry workers were studied for respiratory symptoms, pulmonary function, a nd exposure to dust (total and respirable), endotoxin (respirable and total ), and ammonia. Details of the sampling plan and environmental assessment a re described elsewhere. Relationships between exposures and response were s tudied by correlation and multiple regressions. Significant dose-response r elationships were observed between exposures and pulmonary function decreme nts over a work shift. Exposure concentrations associated with significant pulmonary function decrements were as follows: 2.4 mg/m(3) total dust, 0.16 mg/m(3) respirable dust, 614 EU/m(3) endotoxin, and 12 ppm ammonia.