Short-term exposure to PM_2.5 and high pollution events on depressive symptoms among adolescents

Association between short-term exposure to fine particulate matter (PM_2.5) and adolescent depressive symptoms is an under-investigated area and is worthy of further research. Based on a government surveillance data for 195,687 Chinese adolescents, the mixed-effects logistic regression combined with a distributed lag nonlinear model was used to assess the cumulative effect of PM_2.5 exposure on depressive symptoms. In addition, high pollution events were defined according to World Health Organization (WHO) air quality guidelines (AQGs) and the Chinese ambient air quality standards, and the associations of increased high pollution events with depressive symptoms and the associated excess risk were estimated. Our results showed that association between short-term exposure to PM_2.5 and depressive symptoms was most significant at lag 0 weeks, with each 10 μg/m³ increase in PM_2.5 concentration associated with a 3.11 % (95 % CI: 0.70 %, 5.58 %) change in ORs for depressive symptoms. High pollution events were found to contribute to a maximum 3.12 % (95 % CI: 0.52 %, 5.74 %) excess risk of depressive symptoms when defined as 24-hour average PM_2.5 concentration exceeding 37.5 μg/m³, WHO AQG interim target 3. Our results highlight the importance of air quality improvement for adolescent depression prevention, and recommend increased psychological support during high pollution events.