Ozone Concentration, Physical Activity, and Emotional and Behavioral Problems in Children and Adolescents.

Background: No prior study has examined the mutual association of long-term outdoor ozone (O) concentration and physical activity (PA) with emotional and behavioral problems (EBPs) in children and adolescents. This study aims to investigate the association between long-term outdoor O concentration and the risk of EBPs in children and adolescents and further explore whether increased PA levels modify this association.

Methods: Data were obtained from the 2020 wave follow-up examination of an ongoing prospective cohort study (COHERENCE project) in Guangzhou, China. A total of 419,033 children aged 6-17-year-old were included. Annual average outdoor O concentrations were obtained from the China High Air Pollutants (CHAP) dataset based on participants' residential addresses. PA levels were identified using the International Physical Activity Questionnaire Short Form (IPAQ). EBPs were assessed by the Chinese Parent-Report Strengths and Difficulties Questionnaire (SDQ-P).

Results: Each interquartile range (IQR) increase in outdoor O concentration was associated with an increased odds ratio (OR) for abnormal emotional problems (OR: 1.024, 95% CI: 1.010-1.038), conduct problems (OR: 1.015, 95% CI: 1.002-1.029), peer relationship problems (OR: 1.029, 95% CI: 1.006-1.052), prosocial behavior (OR: 1.023, 95% CI: 1.012-1.034), total difficulties (OR: 1.024, 95% CI: 1.010-1.038), and internalizing behavior (OR: 1.039, 95% CI: 1.026-1.053), in fully adjusted models. The highest OR for abnormal EBPs was observed in children with low PA levels, in combination with high O concentration.

Conclusion: This study identified that long-term outdoor O concentration is associated with an increased risk of EBPs in children and adolescents, with higher PA levels attenuating these risks.