The rate of ozone uptake on carpets: Experimental studies

Ozone can react with surfaces, reducing indoor concentrations. Carpets may be important ozone sinks because of their high surface area. We conducted laboratory experiments to measure ozone uptake on four samples of whole carpet and on the corresponding carpet fibers and carpet backing. Results were parametrized in terms of reaction probability, defined as the rate of ozone loss on a surface normalized by the rate of ozone-surface collisions. For whole carpet and carpet-backing samples, we found the apparent reaction probability to be of magnitude 10(-5) to 10(-4). These results are referenced to the floor area that would be covered by the carpet, rather than to the total surface area of the carpet and its fibers. Reaction probabilities of the order of 10(-7) to 10(-6) were measured on carpet fibers, referenced to total estimated fi ber are a. The results indicate that carpet is of comparable significance to painted walls in scavenging ozone from indoor air. All samples tested exhibited aging, such that the rate of ozone uptake diminished with in creasing cumulative exposure. Although reactions on carpeting can reduce human exposure to ozone, we caution that the reaction products may include volatile carbonyls that have low odor or irritation thresholds.