biostudies-literatureUnknown8(4)Jung YS<h4>Importance</h4>A growing body of research suggests that exposure to fine particulate matter (PM2.5; particle size 2.5 microns or smaller) may be associated with mental health outcomes. However, the potential impact of wildfire-specific PM2.5 exposure on mental health remains underexplored.<h4>Objective</h4>To investigate whether wildfire-specific PM2.5 exposure may be associated with emergency department (ED) visits for mental health conditions, including all-cause and for psychoactive substance use, nonmood psychotic disorders, anxiety, depression, and other mood-affective disorders during the extensive 2020 California wildfire season.<h4>Design, setting, and participants</h4>This cross-sectional study used data on ED visits from July to December 2020 obtained from the California DepaJAMA network opene253326https://www.ebi.ac.uk/biostudies/studies/S-EPMC11971671biostudies-literatureFine Particulate Matter From 2020 California Wildfires and Mental Health-Related Emergency Department Visits.PMC11971671Heft-Neal SNadeau KCJohnson MMBondy MLJung YSChinthrajah RSCullen MRBurke MNelson LDresser CfalseFine Particulate Matter From 2020 California Wildfires and Mental Health-Related Emergency Department Visits.<h4>Importance</h4>A growing body of research suggests that exposure to fine particulate matter (PM2.5; particle size 2.5 microns or smaller) may be associated with mental health outcomes. However, the potential impact of wildfire-specific PM2.5 exposure on mental health remains underexplored.<h4>Objective</h4>To investigate whether wildfire-specific PM2.5 exposure may be associated with emergency department (ED) visits for mental health conditions, including all-cause and for psychoactive substance use, nonmood psychotic disorders, anxiety, depression, and other mood-affective disorders during the extensive 2020 California wildfire season.<h4>Design, setting, and participants</h4>This cross-sectional study used data on ED visits from July to December 2020 obtained from the California Depa2025-01-01T00:00:00Z2025 Apr2025-07-08T03:13:37.267Z2025-07-08T03:13:37.267ZS-EPMC119716714018406510.1001/jamanetworkopen.2025.3326