A passive tobacco smoke exposure system for laboratory animals.

A simple passive tobacco smoke exposure system was developed for laboratory animals. The system consisted of a tobacco smoke generator and an exposure chamber. Performance testing was conducted using Fischer 344 rats. The rats were exposed to passive tobacco smoke generated by 20 cigarettes per day for 3 months. The concentration of the cigarette smoke aerosol (particle phase) in the chamber can be kept almost constant during exposure. The daily average mass concentration was 10.0 +/- 4.3 mg/m3 and the carbon monoxide was 79 +/- 22 ppm during exposure.