The tracer gas technique--a useful tool for industrial hygiene

The tracer gas technique was applied in industrial hygiene surveys. Carbon dioxide, nitrous oxide, and sulfur hexafluoride were used to elicit ventilation rates and determine spreading routes of dilution air in the work environment. The continuous monitoring of nitrous oxide with an infrared spectrophotometer was found to be the most practicable choice for ventilation testing, whereas plastic bag sampling of nitrous oxide or sulfur hexafluoride with subsequent analysis by gas chromatography appeared to be a good method for emission spreading studies. The local flow rates of dilution air and the percentages of make-up air present were the most important information gained in the ventilation studies.