The Influence of Chemical Interactions At the Human Surface on Breathing Zone Levels of Reactants and Products
Using computational fluid dynamics simulations of an occupant in a ventilated room, we find that breathing zone ozone levels can be substantially lower and ozone reaction products associated with human surfaces (ORPHS) levels considerably higher than room levels. For air exchange rates <3/h, the ratio of the breathing zone to the ozone concentration 1 m from the body (bulk air), rozone, ranges from 0.59 to 0.75 for floor or ceiling air supply. ORPHS are enriched in the breathing zone, with concentrations for these conditions ranging from 1.2 to 2.5 greater than bulk air concentrations. at high air exchange rates (>8/h), the breathing zone concentrations approach bulk air concentrations (rozone > 0.9) with a floor supply, whereas large concentration gradients occur between breathing zone and bulk air with a ceiling supply. at these high air exchange rates, ORPHS levels are 1.6-2.0 and 2.9-6.0 times the bulk air concentrations for floor and ceiling supply, respectively. the extent of depletion of ozone or enrichment of ORPHS is large enough that reliance on micro-environmental measurements alone, to assess the intake of ozone or ORPHS, is undesirable.
D. Rim et al., "The Influence of Chemical Interactions At the Human Surface on Breathing Zone Levels of Reactants and Products," Indoor Air, Wiley-Blackwell, Jan 2009.
The definitive version is available at http://dx.doi.org/10.1111/j.1600-0668.2009.00595.x
Civil, Architectural and Environmental Engineering
National Science Foundation (U.S.)
University of Texas at Austin
Keywords and Phrases
CFD; Breathing Zone Concentration; Exposure; Human Surface; Ozone Reaction Products
Article - Journal
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