ABSTRACT
The impact of the built environment on public health is complex, involving several determinants of health including indoor air quality. People who spend the most time indoors can be exposed to indoor air pollutants for long periods of time. These are often the same people who are most susceptible to adverse effects if exposures are high enough (young children, elderly, and chronically ill, especially those suffering from respiratory diseases). An analysis of data on selected indoor volatile organic compounds (VOCs) from community studies in Alberta, Canada was undertaken. Measures of typical (central tendency) and high end (upper limit) indoor concentrations were estimated from seven studies in Alberta. Best estimates of central tendency indoor concentrations for 12 VOCs—benzene, ethylbenzene, o-xylene, 3-methylhexane, heptane, octane, nonane, decane, 1,1,1-trichloroethane, carbon tetrachloride, tetrachloroethylene, and 1,2,4-trimethylbenzene—were less than 5 μg/m3. Best estimates of central tendency indoor concentrations for three VOCs—toluene, m/p-xylene, and limonene—were greater than 5 μg/m3. In the case of best estimates of upper limit indoor concentrations—benzene, ethylbenzene, o-xylene, hexane, 3-methylhexane, heptane, octane, nonane, carbon tetrachloride, and tetrachloroethylene had upper limit concentrations less than 15 μg/m3. Best estimates of upper limit indoor concentrations for toluene, m/p xylene, decane, limonene, 1,1,1-trichloroethane, and 1,2,4-trimethylbenzene were greater than 15 μg/m3. Upper limit concentrations observed inside Alberta residences were about 4 to 10 times higher than typical concentrations for most of the VOCs observed. Upper limit indoor concentrations for carbon tetrachloride and benzene in Alberta are similar to or greater than levels judged by US EPA to imply a concern for potential cancer effects. This indicates that some homes in Alberta can have levels of carbon tetrachloride and benzene that may be of concern from a public health point-of-view.