Depression and Anxiety Associated with Exposure to Fine Particulate Matter Constituents: A Cross-Sectional Study in North China

The association between fine particulate matter (PM2.5) exposure and mental disorders is attracting increasing attention, but the roles of specific PM2.5 chemical constituents have yet to be explored. We conducted a multicenter cross-sectional study in nine cities located in the Beijing-Tianjin-Hebei region in China to assess the effects of PM2.5 and chemical constituents on depression and anxiety. The Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder (GAD-7) scale were used to quantify the depression and anxiety status, atmospheric monitoring data from fixed stations was used to calculate exposure concentrations. We performed multiple logistic regression models to assess the associations of PM2.5 chemical constituents exposure over the preceding 2 weeks with depression and anxiety. Overall, anxiety and depression were significantly associated with organic carbon (OC), elemental carbon (EC), copper (Cu), cadmium (Cd), nickel (Ni), and zinc (Zn). Subgroup analysis showed a stronger effect of PM2.5 constituents on depression during the heating period. This study provide evidence for the possible link between PM2.5 constituents and mental disorders among middle-aged and elderly Chinese adults, which requires further validation of the causal correlation. Our findings support the need for a stricter regulation on emissions of certain specific constituents, in addition to targeting control of total PM2.5 emission concentration.