Measured influence of overhead HVAC on exposure to airborne contaminants from simulated speaking in a meeting and a classroom
Brett C. Singer, Haoran Zhao, Chelsea V. Preble, William W. Delp, Jovan Pantelic, Michael D. Sohn, Thomas W. Kirchstetter
Abstract
was released at the head of one manikin in each experiment to simulate small (<5 µm diameter) respiratory aerosols. The metric of exposure relative to perfectly mixed (ERM) is introduced to quantify impacts, based on measurements at manikin heads and at three heights in the center and corners of the room. Chilled or neutral supply air provided good mixing with ERMs close to one. Thermal stratification during heating produced higher ERMs at most manikins: 25% were ≥2.5 and the highest were >5× perfectly mixed conditions. Operation of two within-zone air cleaners together moving ≥400 cmh vertically in the room provided enough mixing to mitigate elevated exposure variations.