Ozone Initiated Secondary Emissions of Aldehydes from Indoor Surfaces

Surfaces in the presence of ozone may contribute significantly to indoor air pollution. Ozone-induced formation of aldehydes was studied to determine how daily use consumer products contribute to secondary emissions. A field ready method was developed to quantify secondary emission rates on existing surfaces. Four different products, canola cooking oil, a spray cooking oil, bath soap, and a liquid detergent, were evaluated after being coated on a laminated countertop. Upon exposure to 100 ppb O3, nonanal and hexanal were emitted at rates similar to secondary emission rates from carpet. Total aldehyde emission rates from canola oil, soap, and spray cooking oil were respectively 180, 110, 125 µg m-2 h-1. The liquid detergent released small amounts of hexanal, octanal, and nonanal. The aldehyde emission pattern from these products roughly correspond to the anticipated relative aldehyde emission rates due to the proportion of unsaturated fatty acids in vegetable oils and animal fats. If a substantial area of indoor surfaces are coated with these products, secondary emission rates of aldehydes (especially nonanal) may result in concentrations approaching or exceeding odor thresholds