Effects of room ozonation on air quality and pig performance

Reducing odor emissions from swine farms to avoid complaints about odor nuisance is a major issue. Ozonation has been used to reduce odor in swine buildings, but little research exists on its benefits. A swine-finishing building was divided into two identical rooms and two treatments, ozonation and the control, were applied in a cross-over design. The treatments were switched between rooms every three weeks. The overall experimental period was 12 weeks, during which there were four trials. Pig growth performance, dust mass and size concentration, odor intensity, total sulfur compounds, hydrogen sulfide concentration, ammonia concentration, and total heterotrophic bacterial counts were measured and analyzed during the test period. Sulfur-containing compounds detected included dimethyldisulfide, dimethyl sulfide (methanethiol), and dimethyltrisulfide. Ozone application to a swine building at the maximum safe concentration of 0.1 ppm did not have any statistically significant effects on dust mass concentration, odor concentration and emission rate, sulfur compound concentrations, and bacteria counts. However, it did increase ammonia concentration and decrease pig average daily gain. The ozonation effects on hydrogen sulfide concentration could not be evaluated by the gas tube method used during this study.