MODELING OZONE DEPOSITION ONTO INDOOR RESIDENTIAL SURFACES

Modeling the deposition of pollutants onto surfaces requires the inclusion of two separate components: (1) the transport of the pollutant to the surface and (2) the subsequent uptake of the pollutant onto the surface. The relationship of these two components to the deposition velocity can be written in the form of two resistances corresponding to the two components (i.e., the boundary layer resistance and the surface uptake resistance). In order to calculate the surface uptake resistance, the mass accommodation (or ''sticking'') coefficient is required. We present an experimental method for determining accurately the mass accommodation coefficient and report the results of measurements on several common indoor surfaces. For ozone deposition onto glass, latex paint, and vinyl and paper wallpaper, the mass accommodation coefficients were in the range of 10(-5)-10(-7). It Was found that for the surfaces tested, the deposition was governed by one of three conditions, depending on the airflow conditions: (1) surface uptake is rate limiting, (2) boundary layer transport is rate limiting, or (3) both boundary layer transport and surface uptake are important.