Pediatric Psychiatric Emergency Department Utilization and Fine Particulate Matter: A Case-Crossover Study

BACKGROUND: Acute exposure to ambient particulate matter [Formula: see text] in aerodynamic diameter ([Formula: see text]) has been associated with adult psychiatric exacerbations but has not been studied in children. OBJECTIVES: Our objectives were to estimate the association between acute exposures to ambient [Formula: see text] and psychiatric emergency department (ED) utilization and to determine if it is modified by community deprivation. METHODS: We used a time-stratified case-crossover design to analyze all pediatric, psychiatric ED encounters at Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio, from 2011 to 2015 ([Formula: see text]). Conditional logistic regression models adjusted for temperature, humidity, and holiday effects were used to estimate the odds ratio (OR) for a psychiatric ED visit 0–3 d after ambient [Formula: see text] exposures, estimated at residential addresses using a spatiotemporal model. RESULTS: A [Formula: see text] increase in [Formula: see text] was associated with a significant increase in any psychiatric ED utilization 1 [[Formula: see text] 1.07 (95% CI: 1.02, 1.12)] and 2 [[Formula: see text] 1.05 (95% CI: 1.00, 1.10)] d later. When stratified by visit reason, associations were significant for ED visits related to adjustment disorder {e.g., 1-d lag [[Formula: see text] 1.24 (95% CI: 1.02, 1.52)] and suicidality 1-d lag [[Formula: see text] 1.44 (95% CI: 1.03, 2.02)]}. There were significant differences according to community deprivation, with some lags showing stronger associations among children in high versus low deprivation areas for ED visits for anxiety {1-d lag [[Formula: see text] 1.39 (95% CI: 0.96, 2.01) vs. 0.85 (95% CI: 0.62, 1.17)] and suicidality same day [[Formula: see text] 1.98 (95% CI: 1.22, 3.23) vs. 0.93 (95% CI: 0.60, 1.45)]}. In contrast, for some lags, associations with ED visits for adjustment disorder were weaker for children in high-deprivation areas {1-d lag [[Formula: see text] 1.00 (95% CI: 0.76, 1.33) vs. 1.50 (95% CI: 1.16, 1.93)]}. DISCUSSION: These findings warrant additional research to confirm the associations in other populations. https://doi.org/10.1289/EHP4815