Indoor chemistry: Ozone and volatile organic compounds found in tobacco smoke

The deliberate generation of ozone in indoor settings has been promoted as a method to reduce the concentration of indoor pollutants. The present study examines the effect of ozone on a subset of volatile organic compounds (VOCs) found in tobacco smoke. The decays of these compounds were measured in a static room-sized chamber: (1) in the absence of ozone, (2) in the presence of moderate ozone concentrations (<0.115 ppm), and (3) in the presence of high ozone concentrations (<1.4 ppm). At moderate ozone concentrations there was little effect on the monitored VOCs. At high ozone concentrations there was a small, unanticipated reduction in the concentration of some of the saturated VOCs, apparently caused by OH radicals produced as a consequence of the ozone/alkene reactions. There was also a much larger reduction in the concentrations of those compounds with unsaturated carbon bonds. However, this reduction was largely matched by an increase in the concentration of a number of aldehydes. Some of these aldehydes are more potent irritants than their precursors. Furthermore, even a relatively small ventilation rate (similar to0.1 h(-1)) would produce a greater reduction in the monitored VOCs than that produced by a moderate amount of ozone.