Description
Traffic related pollution has been studied in the past decades as the causal agent of numerous adverse health outcomes, including respiratory and cardiovascular diseases, cancer and recently adverse pregnancy outcomes. Air pollutants produced by traffic sources are of particular interest due to their toxicity. These include carbon monoxide (CO), particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5), and polycyclic aromatic hydrocarbons (PAHs). Studies indicate strong spatial gradients in concentrations of traffic-related pollutants with peaks near roadways. Since measurement for traffic exhaust constituents are very costly and ambient air monitors do not reflect the exact personal exposure in a study, a number of surrogate exposure measures have been utilized in large population-based epidemiologic studies. These measures have included residential or school distance to roadways, traffic counts on roadways or highways near homes, and self-reported traffic density and type on the street of residence. Most studies have been performed in developed countries with substantial traffic data and using birth records. Due to high levels of traffic in the border city of Tijuana, BC, studies on the reproductive outcomes of pregnant women residing in Tijuana are needed. However, birth records often contain incomplete or incorrect addresses and traffic data for the city is limited. In this situation, a validated questionnaire for traffic exposure is particularly needed for this population. Self report of traffic near the home has been validated for epidemiologic studies in Europe and elsewhere, but has not been assessed for this area. This study attempted to validate a traffic questionnaire used for relating traffic exposure to respiratory symptoms in studies in Europe for pregnant women in this border city. Pregnant women (n = 107) living in Tijuana, BC, and working in a maquiladora were given a questionnaire for respiratory symptoms/diseases during pregnancy and self perception of traffic in roads near residence. Traffic counts were made at each location visually on site and a video was also recorded. Self-perception of traffic was related to semi truck counts near residence but not to other measures of auto traffic and large vehicle traffic. Self-report of rhinitis during pregnancy was significantly associated with self report of continuous truck traffic near the home. Subjects also identified other sources of air pollution, including the burning of material such as trash and tires near residences. Based on the vehicle mix recorded on city streets near residences of pregnant women in the city of Tijuana, modifications to the questionnaire are suggested, such as adding more categories regarding buses, small informal buses, and motorcycles. High traffic near the home documented for many subjects emphasizes the need for health related studies regarding the exposure of Tijuana residents to high traffic.
