[A systematic review of association between fine particle exposure and children's behavior]

Objective: To systematically analyze the impact of PM_2.5 exposure on children's behavior. Methods: Use air pollution, fine particulate matter, children, students, child behavior, neurobehavior, attention, autism, autism spectrum disorder, attention deficit hyperactivity disorder, hyperactivity, and bad behavior as Chinese keywords. Use air pollution, fine particulate matter, particulate matter, PM_2.5, children, student, behavior, autism, attention, intention, neurobehavior, attention deficit hyperactivity disorder, ADHD, ASD as English keywords. Journal papers and grey literature were searched from CNKI, Wanfang Data Knowledge Service Platform, PubMed and Web of Science database from their inception to Nov 2019, which are related to PM_2.5 and children behavior problems. The search period is as of November 2019, and the languages are limited to Chinese and English. The inclusion criteria included the exposure factor of the study as PM_2.5; the results of the study included behavioral disorders and related diseases; the languages of the included literature were Chinese and English; original research papers; case-control, cohort or cross-sectional studies. Exclusion criteria include animal experiments; repeated reports; review articles; research exposure factors do not include PM_2.5; children self-harm and illegal behaviors. Finally, 25 articles were included. Results: Among the 25 included articles, 12 studies discussed the relationship between PM_2.5 exposure and childhood behavioral disorders, 13 discussed the relationship between PM_2.5 exposure and abnormal behaviors in children, and 5 studies based on the Chinese population. According to the research design, it is divided into birth cohort studies (15), cross-sectional studies (5), and case-control studies (5). China mainly uses cross-sectional studies and case-control studies. The results of the study suggest that PM_2.5 exposure will increase the risk of children's behavioral problems, with both short-term and long-term effects. Short-term exposure to PM_2.5 can easily cause mild abnormal behaviors in children, and long-term exposure may increase the risk of children's behavioral disorders. The fetal period and the infant period may be the key exposure window for the occurrence of children's behavior problems. Conclusion: There may be a certain correlation between PM_2.5 exposure and children's behavioral problems. In future studies, longitudinal cohort studies should be carried out to enhance the causal relationship between fine particulate matter pollution and children's behavioral problems.