Respiratory symptoms in primary schoolchildren living near a freeway in Taiwan.

A cross-sectional epidemiological study was conducted in an effort to investigate the effects of automobile exhaust on respiratory symptoms of school children in Kaohsiung, Taiwan. One school (Yang-Ming primary school) was located in the vicinity of 150 m from the highway and designated as a heavy-traffic area. The control school (Zhuang-Jing primary school) was situated in the same district but the distance of the school address to the freeway was 1500 m and designated as a low-traffic area. All of the primary school children in those schools were used in the study. In total, 3221 children were from the heavy-traffic school and 2969 from the low-traffic area. The respiratory health was assessed by an evaluation of the child's respiratory symptoms and illnesses using a parent-completed questionnaire. Data on traffic flow on the freeway were obtained from the Department of Transportation. Road traffic flows in front of the study schools were also measured with a portable counter. This study showed that a freeway surrounding a child's school may not be associated with an increased risk of respiratory symptoms. This may be due to insufficiently large contrasts in traffic pollution levels between these areas.