Ozone Loss: A Surrogate for the Indoor Concentration of Ozone-Derived Products

Ozone concentrations tend to be substantially lower indoors than outdoors, largely because of ozone reactions with indoor surfaces. When there are no indoor sources of ozone, a common condition, the net concentration of gaseous products derived from indoor ozone chemistry scales linearly with the difference between outdoor and indoor ozone concentrations, termed ozone loss. As such, ozone loss is a metric that might be used by epidemiologists to disentangle the adverse health effects of ozone's oxidation products from those of exposure to ozone itself. The present paper examines the characteristics, potential utility, and limitations of the ozone loss concept. We show that for commonly occurring indoor conditions, the ozone loss concentration is directly proportional to the total rate constant for ozone removal on surfaces (k(sum)) and inversely proportional to the net removal of ozone by air exchange (?) plus surface reactions (k(sum)). It follows that the ratio of indoor ozone to ozone loss is equal to the ratio of ? to k(sum). Ozone loss is a promising metric for probing potential adverse health effects resulting from exposures to products of indoor ozone chemistry. Notwithstanding its virtues, practitioners using it should be mindful of the limitations discussed in this paper.

Automated summary

Indoor ozone concentrations are generally lower than outdoor concentrations due to ozone reactions with indoor surfaces. The concept of ozone loss, which represents the net concentration of gaseous products derived from indoor ozone chemistry, can be used to differentiate the health effects of ozone's oxidation products from direct exposure to ozone itself. The ozone loss concentration is directly related to the rate of ozone removal on surfaces and inversely related to the net removal of ozone by air exchange and surface reactions. Ozone loss shows promise as a metric for studying the potential adverse health effects of indoor ozone chemistry, but its limitations should be considered.