Analysis of Pediatric Acute Upper Airway Pathology During Local Wildfires and Increased PM 2.5 Burden

As wildfires worldwide increase in severity and frequency, fine particulate matter (PM 2.5), generated as a component of wildfire smoke, increasingly impacts air quality. Children are particularly vulnerable to poor air quality in numerous ways, including inhalation of more air in proportion to their body size than adults. Though its adverse impacts on the lower airway are well demonstrated, the clinical effects of PM 2.5 on the pediatric upper airway are poorly understood and warrant investigation.

Retrospective cohort study.

Tertiary academic medical center.

From 2014 to 2023, patient presentations to a pediatric emergency department in Northern California during exposure periods of elevated PM 2.5 burden associated with nearby wildfires were identified. Patient diagnoses, presenting symptoms, and management were analyzed. Comparison group patients were evaluated during date-matched control periods with confirmed normal air quality. Chi-squared analyses determined significance.

During periods of increased wildfire-generated PM 2.5 burden, a significantly greater proportion of pediatric patients presented to the emergency department with upper airway pathology compared to matched control periods of healthy air quality. Further, a significantly greater proportion of patients were diagnosed with croup during wildfires. Of patients presenting with upper airway pathology, a significantly greater proportion experienced dysphonia during wildfires and had a negative strep test.

Wildfire-generated PM 2.5 may contribute to increased rates of croup presentations, and PM 2.5 may disproportionately affect the larynx in the pediatric upper airway. Larger population-based studies and preclinical models may clarify these clinical manifestations of a growing public health threat.