Predictors of indoor BTEX concentrations in Canadian residences

Background: Benzene, toluene, ethylbenzene and m-, p-xylenesand o-xylene (BTEX) are a group of volatile organic compounds that originate from similar sources. Given the potentially negative health implications of BTEX exposure and their prevalence in residential indoor air, it is important to understand typical residential concentrations and identify predictors.

Data and methods: The 2009 to 2011 Canadian Health Measures Survey included an indoor air component. Questionnaires were administered, and respondents were asked to deploy an air sampler in their home for 7 consecutive days. This analysis is based on BTEX data from 5,191 respondents. Mean BTEX concentrations were examined overall, and by dwelling type and garage configuration. Stepwise regression models were used to examine potential sources of BTEX components.

Results: Means were 1.95 μg/m³ (benzene), 19.17 μg/m³ (toluene), 4.09 μg/m³ (ethylbenzene), 14.42 μg/m³ (m-, p-xylenes), and 4.16 μg/m³ (o-xylene). Significant predictors of the presence of BTEX included a garage on the property, regular smoking in the home, renovations in the past month, number of occupants, use of paint remover, and use of fragrance.

Interpretation: Results of this nationally representative study found that BTEX concentrations are relatively low among Canadian residences, and identified several different indoor sources.