Positive human health effects of dust suppression with canola oil in swine barns

A crossover trial was conducted to evaluate the acute human health effects of a dust control technology in a swine confinement facility. Twenty lifetime nonsmoking male subjects, with no evidence of allergy or asthma and no previous swine barn exposure, participated in the study, which included a laboratory session (baseline), 5-h exposure in a swine room sprinkled with canola oil (treatment) and 5-h exposure in a traditional swine room (control). Mean values of inhalable dust concentrations and endotoxin levels in the control room were significantly greater than those observed in the treatment room. Mean shift changes in FEV1 from preexposure to end of exposure were 1.1% (standard error, 0.63%) on baseline day, -1.9% (0.63%) on treatment day, and -9.9% (1.12%) on control day; the differences in the shift changes were statistically significant. Mean value of methacholine concentration that reduced the FEV1 by 20% (PC20) in bronchoprovocation tests on baseline day was significantly different from that on treatment day (p = 0.04) and that on control day (p < 0.001). Significant increases were also observed in white blood cell counts and nasal lavage cell counts on the control day in comparison with the other two days. Blood neutrophil counts after control room exposure were twice those observed on baseline and after exposure to the treatment room. Significant differences were also observed in IL-1 beta, IL-6, and IL-8 nasal lavage cytokines and in IL-6 serum cytokine. These results suggest that the canola oil dust control method is effective in improving indoor air quality in swine barns and reducing acute health effects in naive healthy subjects.