ACUTE RESPIRATORY RESPONSES OF HUMAN-SUBJECTS TO AIR-QUALITY IN A SWINE BUILDING

The purpose of this study was to test the following hypotheses: (1) an air quality control strategy can be directly evaluated by measuring r espiratory responses of a human subject; and (2) improved air quality can improve human respiratory responses in swine building environments . Twenty human subjects, between 18 and 35 yr of age, who had never be en exposed to an enclosed swine environment before, were exposed to ai r qualities in a treatment room and a control room, in a swine buildin g. The treatment room was sprinkled with crude canola oil, which reduc ed the dust, endotoxin, ammonia and hydrogen sulphide by 93% (from 2.4 1 to 0.15 mg/m(3)), 89% (from 3984 to 452 EU/m(3)), 30% (from 26 to 18 .3 p.p.m.) and 27% (from 0.38 to 0.27 p.p.m.), respectively, compared with the control room. The control room was identical to the treatment room but had no oil sprinkling treatment. Each subject spent 5 h in e ach room. They were scheduled to do a bicycle exercise that was intend ed to simulate the barn workers' workload. Shift changes in forced exp iratory volume in 1 s (FEV1), forced vital capacity (FVC) and white bl ood count (WBC) of the subjects between the treatment and the control were all significantly different (p < 0.03). Shift changes of FEV1 wer e -1.94% for the treatment and -9.93% for the control. Shift changes o f WBC were 6.35 count/mu l for the treatment and 8.78 count/mu l for t he control. Means (+/- SE) of methacholine challenge (MC) were 181 +/- 108 and 140 +/- 113 mg/ml for the treatment and the control, respecti vely, but they were not significantly different (p = 0.18) due to the large variation in values. This study demonstrated that (1) an air qua lity control strategy could be directly evaluated by measuring human r espiratory responses; and (2) improved air quality (e.g. oil sprinklin g) resulted in improved acute respiratory responses of human subjects. (C) 1998 Silsoe Research Institute.