Gu X, et al. - Via a systematic review and meta-analysis of case-crossover and cohort studies, researchers appraised the overall relationship between PM2.5 (particles with an aerodynamic diameter of 2.5 µm or less) or PM10 (particles with an aerodynamic diameter between 2.5 and 10 µm) exposure and depression/suicide. For the meta-analysis, they included 14 articles (7 for depression and 7 for suicide) with data from 684,859 participants. Outcomes revealed a strong association of an increase in ambient PM2.5 concentration with increased depression risk in the general population. the association appeared stronger at long-term lag and cumulative lag patterns, suggesting a potential cumulative exposure effect over time.