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Preliminary Study Links 2023 Wildfire Smoke to Increased Stroke Incidence in New Jersey

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Canadian Wildfires Linked to Increased Stroke Rates and Severity in New Jersey, Preliminary Study Finds

A preliminary study indicates an association between elevated air pollution levels stemming from the 2023 Canadian wildfires and an increased rate and severity of stroke in New Jersey. The research suggests that short-term exposure to pollutants, specifically ozone and fine particulate matter, may impact neurological health.

Study Methodology

Researchers examined stroke cases identified through a stroke registry during June and July 2023, comparing them to the same period in 2022. Air quality data was collected from U.S. Environmental Protection Agency (EPA) monitors in Camden, New Jersey, focusing on daily average exposures to ozone and fine particulate matter (PM2.5). The analysis also considered pollutant levels from the one to two days preceding a stroke event. The study's findings are scheduled for presentation at the American Academy of Neurology's 78th Annual Meeting in April 2026.

Air Quality During 2023 Wildfire Period

During the 2023 wildfire period, air pollutant levels in Camden, New Jersey, were recorded as significantly higher than median concentrations:

  • Ozone: Levels peaked at 136 parts per billion (ppb), compared to a median concentration of 36 ppb. The World Health Organization (WHO) guideline for ozone is 50 ppb. Approximately 28% of the study days experienced ozone levels above this 50 ppb guideline.
  • Particulate Matter (PM2.5): Levels reached 211 micrograms per cubic meter (µg/m³), exceeding a median concentration of 48.5 µg/m³. About 38% of the days during the study period had above-average particulate matter levels.

Key Findings

The study reported specific associations between elevated pollutant levels and stroke metrics:

  • Ozone Exposure:
    • On days with ozone levels exceeding the 50 ppb WHO guideline, the incidence of stroke was 1.25 strokes per day, compared to 0.93 strokes per day on days with lower ozone levels.
    • After adjusting for factors including age, sex, race, and stroke cause, higher average ozone days were associated with a 0.32 higher incidence of stroke per day.
    • Strokes occurring on days with elevated ozone levels showed a higher proportion of bleeding strokes and an increased occurrence of large artery atherosclerosis.

"Higher average ozone days were associated with a 0.32 higher incidence of stroke per day."

  • Particulate Matter (PM2.5) Exposure:
    • Days with above-average particulate matter levels were associated with longer hospital stays for stroke patients.
    • These days also corresponded to higher scores on scales measuring stroke severity.

Context and Limitations

Elizabeth Cerceo, MD, of Cooper Medical School of Rowan University and one of the study authors, noted that while long-term air pollution is a recognized stroke risk factor, less is known about the neurological impact of short-term exposure to wildfire smoke. The study authors suggest these findings may offer information for stroke prevention strategies and public health interventions during wildfire events.

The study has several limitations, including:

  • Its focus on a short wildfire period.
  • The use of daily average pollutant levels, which may not fully capture hourly variations.
  • The exclusion of other environmental factors such as humidity and barometric pressure from the analysis.

Researchers plan to investigate longer periods in future studies to provide a more comprehensive understanding of this association.