Air Exchange

Quantification of an indoor population by means of air exchange rates and carbon dioxide gas concentrations:
A technique is presented to extend the utility of commercially available dataloggers to provide information on the ventilation effectiveness and air exchange rate of a compartment. An electronic aimed sampling valve was used to collect air alternatively from the room exhaust and the breathing zones of occupants. The timed valve provided a data set for each location that was fitted to an exponential one-compartment clearance model. The fitted data were used to calculate air exchange, mean air life, half-life of room air, ventilation effectiveness, and correlation of fit. The technique used ambient carbon dioxide gas concentrations as a natural tracer, or compressed carbon dioxide as a pulse-inject tracer gas