Sensor for Detection of Tobacco Smoke Particulates in Inhalation Exposure Systems

A commercially available light emitting diode/phototransistor array was investigated for detection and analysis of tobacco smoke in the Walton Horizontal Smoking Machine (WHSM) animal inhalation exposure system. The diode element of the device emits light into the smoke aerosol, and light back-scattered by the smoke particles is detected by the phototransistor element. The sensor provides a continuous, nearly instantaneous graphicaI visualization of smoke particulates in the immediate vicinity of the array. Experimental studies showed that sensor readout is Iinearly related to smoke particulate concentration of the smoke and is independent of the composition of the smoke. Smoke particle agglomeration associated with aging of smoke causes observable but minor changes in sensor response.