contaminant uniformity

Air and airborne contaminant mixing in building spaces is important to ventilation system design and performance, tracer gas measurements of ventilation rates, and occupant exposure to indoor pollutants. The physics of air and contaminant mixing have been studied for decades and are fairly well understood. Nevertheless, many discussions of building ventilation, air movement and indoor air quality use the term “perfect mixing” without a clear discussion of what it means or how it applies to the situation being considered.