OZONE REACTIVE CHEMISTRY ON INTERIOR LATEX PAINT

The heterogeneous chemistry of ozone on interior latex paint was inves tigated in a tube flow reactor. The emissions of several polar volatil e organic compounds (VOCs) including organic acids and carbonyls (alde hydes and ketones) were measured while a glass tube coated with latex paint was exposed to clean air and ozone, Four different commercial br ands of latex paint were tested. Formic and acetic acids were not foun d to be generated via ozone reactions; however, both were found to off -gas from the latex paints, and the off-gasing increased with increasi ng relative humidity. The off-gasing rates are large enough, particula rly for acetic acid, to impact residential. concentrations significant ly. Formaldehyde was found to be produced by reactions related to the ozone concentration. There was some evidence that acetaldehyde and ace tone may also be produced by processes related to the ozone concentrat ion. A steady-state model is presented that is used to extrapolate the chamber results to a representative indoor environment. The model is based on an experimentally derived parameter termed the VOC formation factor, which is defined as the number of VOC molecules of a particula r species formed via an ozone reaction divided by the total number of ozone molecules sticking to the surface. Using this model, it was foun d that formaldehyde production via ozone reactions is significant enou gh to impact indoor concentrations of formaldehyde.