Ozone-Real Indoor Surfaces Reactions in Four Residences
Field experiments were conducted in four residential homes during summer to quantify ozone-induced secondary emission rates (SERs) of aldehydes on indoor surfaces. Four surfaces in each house were examined: living room carpet, living room wall, kitchen floor, and kitchen counter. Upon exposure to ozone for 3 hours, formaldehyde and C3- C10 saturated aldehydes, especially nonanal, were emitted as products of ozone-surface reactions. Carpet in newer homes had higher SERs than carpet in older homes. For example, the nonanal SER from the living room carpet was 80µg m-2 h-1 in a 1 year old home, but only 8-20 µg m-2 h-1 in two homes that were greater than 10 years old. All kitchen countertops were very reactive and high SERs were observed, especially for nonanal. Product yields from countertops were consistent with the products of ozone reactions with oleic and linoleic esters, common in cooking oils. These findings suggest that carpet surfaces become depleted of reactants as they become oxidized over time. However, countertop surfaces, that are cleaned frequently or become covered in cooking oils, are continuously replenished with reactants. Over time, countertops may become the dominant contributor to indoor concentrations of secondary aldehydes. However, when total surface area is taken into account for the homes assessed, carpet is predicted to be the primary source of secondary emissions, even for older homes.
H. Wang and G. Morrison, "Ozone-Real Indoor Surfaces Reactions in Four Residences," Indoor Environmental Quality: Problems, Research and Solutions, Air and Waste Management Association, Jul 2006.
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Secondary Emission Rates (SERs); Aldehydes; Indoor air quality; Ozone
Article - Conference proceedings
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01 Jul 2006