Determining the Outdoor Air Ventilation with Carbon Dioxide (CO2) as a Tracer Gas

Abstract

Insufficient ventilation can lead to occupant complaints of discomfort and reduced productivity as human and building generated pollutants build up. Some combinations of these elevated pollutants may have short or long-term detrimental health effects. Carbon Dioxide (CO2) is very rarely a pollutant of direct health concern itself. Rather a tracer gas, because building occupants exhale CO2 and is used as a tracer gas that is an excellent indicator of adequate (or inadequate) ventilation. Keeping in view this fact we measured CO2 as a marker, or tracer gas, to determine the outdoor air ventilation (dilution air) rate in an occupied space. Low CO2 concentration, when measured during periods of average and higher occupancy, implies that human generated pollutants are being properly diluted. And in the absence of a specific pollutant source, it is a rough estimator that the thousands of potential building generated pollutants are being dispersed. This makes it a key indoor air quality indicator.