Assessing traffic and polycyclic aromatic hydrocarbon exposure in Montreal, Canada

The International Agency for Research on Cancer classifies specific polycyclic aromatic hydrocarbons (PAHs) as probable carcinogens. This study compares two PAH biomarkers and their relationship with geographic information system (GIS) based traffic density (a proxy of PAH exposure), and explores the determinants of the PAH biomarkers.

A cross-sectional study was conducted in Montreal with 200 volunteers (107 females and 93 males) ages 20 to 53 years. Data were collected by questionnaire, urine samples were used for biomarker analysis, and innovative GIS-based time- and distance-weighted traffic densities (TDWTD) were calculated for all locations of participants during the 48 h prior to urine collection.

Detection rates of the two biomarkers were greater than 95%. Female participants had higher 1-OHP and 1-OHPG levels than males, and no relationship was detected between TDWTD in 48 h and the two PAH biomarkers. Biomarker levels were related to smoking more than one pack of cigarettes in the previous 48 h, and among non-smokers, barbecued meat consumption increased the level of urinary 1-OHP (exp β: 1.45, 95% CI: 1.07 to 1.98).

Both 1-OHP and 1-OHPG can be used to assess the relatively low PAH levels to which the general population is exposed. With the exception of smoking, the impact of PAH exposure factors on the biomarkers is relatively small in this study population.