4. Discussion
Increased traffic density within 200mof the subject's home and
increases in ambient air pollution were both associated with
increased respiratory symptoms. The odds ratios were higher in the
lowest income and education levels for the majority of cases, and in
select instances these increases were statistically significant. For
example, associations by income level when testing traffic counts
were not significant in any case; however, significant associations
were present due to exposure to NO2 for two respiratory outcomes.
Significant results by education level were present when testing the
odds of respiratory ailments due to both factors of traffic counts and
direct air pollution exposure, where all three air pollutants resulted
in significantly higher odds of chest congestion in households with
parents having less than a high school education.
Although numerous studies have focused on the respiratory
health outcomes in children due to air pollution or traffic exposures
(e.g. Lin et al., 2005; Mazaheri et al., 2014; Vanos, 2014), very few
studies have focused on the modifying effects of socioeconomic
differences on respiratory ailments, specifically in children. Understanding
the modifying effects of factors based on such differences
aids in understanding many related explanatory findings and
hypotheses discussed in the literature such as education (Cakmak