2016 Yes https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4829987/ Forns, Joan Europe Observational Epidemiology Study Students Elementary (K-5) Nitrogen Dioxide (NO2) Noise Stress/Anxiety Increases in indoor and outdoor EC, BC, and NO2 concentrations were positively associated with SDQ (behavioral development) total difficulties scores (suggesting more frequent
behavioral problems) in adjusted multivariate models, whereas noise was significantly associated with ADHD-DSM-IV scores.