Abstract
Field indicator tubes were combined witli a flame ionization meter into an inexpensive sampling system for evaluating the entry of vehicle exhaust gases into the air supply of a building. The system yields recorder tracings of hydrocarbon levels and exposure times and automatically samples carbon monoxide, aldehydes, and other toxicants when the hydrocarbon content of the air exceeds predetermined levels. The system was used to monitor the air supply of a building for nine months. Hydrocarbon levels did not correlate with odor intensity. On all occasions concentrations of carbon monoxide were less than 5 ppm, and those of nitrogen dioxide, less than 0.05 ppm. It was concluded that this monitoring system can provide adequate data for objective evaluation of vehicle exhaust gases in the air supply.