Contrasting Health Outcomes following a Severe Smoke Episode and Ambient Air Pollution in Early Life: Findings from an Australian Data Linkage Cohort Study of Hospital Utilization

BACKGROUND: Episodic spikes in air pollution due to landscape fires are increasing, and their potential for longer term health impacts is uncertain. OBJECTIVE: Our objective is to evaluate associations between exposure in utero and in infancy to severe pollution from a mine fire, background ambient air pollution, and subsequent hospital care. METHODS: We linked health records of births, emergency department (ED) visits, and hospitalizations of children born in the Latrobe Valley, Australia, 2012–2015, which included a severe pollution episode from a mine fire (9 February 2014 to 25 March 2014). We assigned modeled exposure estimates for fire-related and ambient particulate matter with an aerodynamic diameter of [Formula: see text] ([Formula: see text]) to residential address. We used logistic regression to estimate associations with hospital visits for any cause and groupings of infectious, allergic, and respiratory conditions. Outcomes were assessed for the first year of life in the in utero cohort and the year following the fire in the infant cohort. We estimated exposure-response for both fire-related and ambient [Formula: see text] and also employed inverse probability weighting using the propensity score to compare exposed and not/minimally exposed children. RESULTS: Prenatal exposure to fire-related [Formula: see text] was associated with ED presentations for allergies/skin rash [odds ratio [Formula: see text] , 95% confidence interval (CI): 1.01, 1.76 per [Formula: see text] increase]. Exposure in utero to ambient [Formula: see text] was associated with overall presentations ([Formula: see text] , 95% CI: 1.05, 1.33 per [Formula: see text]) and visits for infections (ED: [Formula: see text] , 95% CI: 0.98, 1.29; hospitalizations: [Formula: see text] , 95% CI: 1.00, 1.52). Exposure in infancy to fire-related [Formula: see text] compared to no/minimal exposure, was associated with ED presentations for respiratory ([Formula: see text] , 95% CI: 1.05, 1.80) and infectious conditions (any: [Formula: see text] , 95% CI: 0.98, 1.49; respiratory-related: [Formula: see text] , 95% CI: 1.05, 1.83). Early life exposure to ambient [Formula: see text] was associated with overall ED visits ([Formula: see text] , 95% CI: 1.05, 1.30 per [Formula: see text] increase). DISCUSSION: Higher episodic and lower ambient concentrations of [Formula: see text] in early life were associated with visits for allergic, respiratory, and infectious conditions. Our findings also indicated differences in associations at the two developmental stages. https://doi.org/10.1289/EHP12238