Abstract TP125: Short-Term Increases in Ozone and PM2.5 During the 2023 Canadian Wildfires Linked to Increased Stroke Incidence and Severity in Camden, New Jersey

Introduction: Air pollution is a leading environmental health hazard, and both short- and long-term exposures have been linked to increased rates of stroke. In 2023, the Canadian wildfires caused substantial declines in air quality across the Northeastern United States, including New Jersey. Evaluating the impact of this large-scale air pollution event on cerebrovascular health may provide important insights into the relationship between wildfire smoke exposure and stroke incidence and severity. Hypothesis: We hypothesized that higher short-term PM2.5 and ozone exposure would be associated with increased stroke incidence and severity. Methods: We conducted a retrospective study using the Cooper Observational Acute Stroke and Thrombectomy Registry, including all patients with imaging-confirmed ischemic or hemorrhagic stroke at Cooper University Hospital from June-July 2022 and 2023. Daily mean PM2.5 and ozone levels were obtained from EPA air quality monitors in Camden, NJ. Each stroke was linked to air quality values from the same day and the preceding 1-2 days to account for lag effects. Primary outcomes were stroke incidence and proportion of hospital admissions due to stroke. Secondary outcomes included stroke type, etiology, and severity (length of stay [LOS], NIHSS, and change in mRS). Analyses used Mann-Whitney U, Kruskal-Wallis, and Spearman correlation tests. Results: A total of 122 strokes were analyzed (80 below- vs. 42 above-median ozone days; 83 below- vs. 39 above-median PM2.5 days). Higher ozone levels were associated with greater stroke incidence (p=0.016), an increased proportion of hemorrhagic strokes (p=0.027), and more large artery atherosclerosis etiologies (p=0.028), with a trend toward increased ischemic stroke frequency (p=0.07). Elevated PM2.5 was associated with higher NIHSS scores at presentation (p=0.035) and longer LOS (p=0.032). No significant associations were observed for cardioembolic or small vessel disease etiologies. Conclusion: Acute spikes in ozone and PM2.5 during the 2023 Canadian wildfires were linked to increased stroke incidence, hemorrhagic stroke risk, and greater stroke severity in an urban, underserved population. These findings highlight the cerebrovascular hazards of wildfire-related air pollution and the need for targeted public health measures during such events.