INTRODUCTION
Ozone is an air pollutant produced in the lower atmosphere by photochemical reactions.
Higher outdoor ozone concentrations have been linked to asthma exacerbation, respiratory
symptoms, reduced lung function in children, hospital visits, heart attacks, and premature
death (EPA, 2008). Recently, increases in sick building syndrome symptoms among office
workers were also associated with higher outdoor ozone concentrations (Apte et al., 2008;
Buchanan et al., 2008). In buildings, the outdoor air is normally the dominant source. In
addition to the direct health risks of ozone, pollutants created as ozone reacts chemically
indoors (Weschler, 2006) may pose risks.