Air pollution and attention in Polish schoolchildren with and without ADHD.

Background: Development and functioning of attention-a key component of human cognition-can be affected by environmental factors. We investigated whether long- and short-term exposure to particulate matter with aerodynamic diameter < 10 μm (PM) and nitrogen dioxide (NO) are related to attention in 10- to 13-year-old children living in Polish towns recruited in the NeuroSmog case-control study.

Methods: We investigated associations between air pollution and attention separately in children with attention deficit hyperactivity disorder (ADHD, n = 187), a sensitive, at-risk population with impaired attention and in population-based typically developing children (TD, n = 465). Alerting, orienting, and executive aspects of attention were measured using the attention network test (ANT), while inhibitory control was measured with the continuous performance test (CPT). We assessed long-term exposure to NO and PM using novel hybrid land use regression (LUR) models. Short-term exposures to NO and PM were assigned to each subject using measurements taken at the air pollution monitoring station nearest to their home address. We tested associations for each exposure-outcome pair using adjusted linear and negative binomial regressions.

Results: We found that long-term exposures to both NO and PM were associated with worse visual attention in children with ADHD. Short-term exposure to NO was associated with less efficient executive attention in TD children and more errors in children with ADHD. It was also associated with shorter CPT response times in TD children; however, this effect was accompanied by a trend towards more CPT commission errors, suggestive of more impulsive performance in these subjects. Finally, we found that short-term PM exposure was associated with fewer omission errors in CPT in TD children.

Conclusions: Exposure to air pollution, especially short-term exposure to NO, may have a negative impact on attention in children. In sensitive populations, this impact might be different than in the general population.