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Measured influence of overhead HVAC on exposure to airborne contaminants from simulated speaking in a meeting and a classroom.
Singer, Brett C; Zhao, Haoran; Preble, Chelsea V; Delp, William W; Pantelic, Jovan; Sohn, Michael D; Kirchstetter, Thomas W.
  • Singer BC; Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
  • Zhao H; Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
  • Preble CV; Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
  • Delp WW; Department of Civil & Environmental Engineering, University of California, Berkeley, California, USA.
  • Pantelic J; Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
  • Sohn MD; Indoor Environment Group, Energy Analysis and Environmental Impacts Division, Building Technologies and Urban Systems Division, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
  • Kirchstetter TW; Center for the Built Environment, University of California, Berkeley, California, USA.
Indoor Air ; 32(1): e12917, 2022 01.
Article in English | MEDLINE | ID: covidwho-1388295
ABSTRACT
Tracer gas experiments were conducted in a 158 m3 room with overhead supply diffusers to study dispersion of contaminants from simulated speaking in physically distanced meeting and classroom configurations. The room was contained within a 237 m3 cell with open plenum return to the HVAC system. Heated manikins at desks and a researcher operating the tracer release apparatus presented 8-9 thermal plumes. Experiments were conducted under conditions of no forced air and neutral, cooled, or heated air supplied at 980-1100 cmh, and with/out 20% outdoor air. CO2 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.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: Ventilation / Air Pollution, Indoor Language: English Journal: Indoor Air Journal subject: Environmental Health Year: 2022 Document Type: Article Affiliation country: Ina.12917

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Full text: Available Collection: International databases Database: MEDLINE Main subject: Ventilation / Air Pollution, Indoor Language: English Journal: Indoor Air Journal subject: Environmental Health Year: 2022 Document Type: Article Affiliation country: Ina.12917