Neurobehavioral effects of exposure to traffic-related air pollution and transportation noise in primary schoolchildren

Background: Children living close to roads are exposed to both traffic noise and traffic-related air pollution. There are indications that both exposures affect cognitive functioning. So far, the effects of both exposures have only been investigated separately. Objectives: To investigate the relationship between air pollution and transportation noise on the cognitive performance of primary schoolchildren in both the home and school setting. Methods: Data acquired within RANCH from 553 children (aged 9-11 years) from 24 primary schools were analysed using multilevel modelling with adjustment for a range of socio-economic and life-style factors. Results: Exposure to NO2 (which is in urban areas an indicator for traffic-related air pollution) at school was statistically significantly associated with a decrease in the memory span length measured during DMST (chi(2)=6.8, df=1, p=0.01). This remained after additional adjustment for transportation noise. Statistically significant associations were observed between road and air traffic noise exposure at school and the number of errors made during the 'arrow' (chi(2)=7.5, df=1, p=0.006) and 'switch' (chi(2)=4.8, df=1, p=0.028) conditions of the SAT. This remained after adjustment for NO2. No effects of air pollution exposure or transportation noise exposure at home were observed. Combined exposure of air pollution and road traffic noise had a significant effect on the reaction times measured during the SRTT and the 'block' and the 'arrow' conditions of the SAT. Conclusions: Our results provide some support that prolonged exposure to traffic-related air pollution as well as to noise adversely affects cognitive functioning. (C) 2012 Elsevier Inc. All rights reserved.