Los Angeles wildfires linked to spike in heart, lung emergencies, study shows
A new study found a more than 200% rise in health problems requiring emergency medical attention after the January 2025 fires in Los Angeles County.
Extensive fire damage was seen in the Pacific Palisades neighborhood on Friday, Jan. 10, as the fires continued.
Los Angeles residents saw a spike in serious health problems after the January 2025 wildfires, including lung and heart emergencies, according to a new study published in the Journal of the American College of Cardiology.
Researchers analyzed emergency department encounters at Cedars-Sinai Medical Center, the largest adult acute-care hospital in Los Angeles County, focusing on patients from nearly 40 ZIP codes either directly affected by the fires or adjacent to burn areas. The hospital is about 20 miles from where the Eaton and Palisades fires sparked.
A Pacific Palisades mobile home park burned down from the Palisade Fire in Pacific Palisades, California on January 15, 2025. (Photo by Jon Putman/Anadolu via Getty Images)
The study compared emergency visits during the 90 days after Jan. 7, 2025, with the same periods from 2018 through 2024. During that post-fire window, average concentrations of fine particulate matter, known as PM2.5, increased sharply, a key factor linked to wildfire-related health effects.
Overall emergency department volume did not change significantly. However, the researchers found sharp increases in several serious conditions. Emergency visits for acute pulmonary illness rose 24 percent compared to prior years. Encounters for acute myocardial infarction, commonly known as heart attacks, increased by 46 percent.
The most dramatic increase involved systemic illness identified through abnormal blood chemistry results. Emergency encounters coded for chemistry laboratory abnormalities rose by 218 percent during the three months following the fires. These laboratory abnormalities often appeared with patients who had symptoms including chest pain, shortness of breath, dizziness, abdominal pain, fainting, heart rhythm disorders, hypertension, sepsis and lower respiratory illness.
Fire crews walk as they battle the Kenneth Fire in the West Hills section of Los Angeles, Thursday, Jan. 9, 2025. (AP Photo/Ethan Swope)
Study authors said this pattern suggests wildfire smoke exposure may affect multiple organ systems, not just the lungs. Unlike previous wildfire research, which has focused largely on respiratory impacts, the study points to broader effects, particularly after fires that burn in wildland–urban interface areas.
Wildland–urban interface fires burn a mix of vegetation and human-made materials, producing smoke that contains a more complex mixture of chemicals and toxic metals than smoke from wildland-only fires. Prior research has shown these pollutants can affect immune function and cardiovascular health.
The Los Angeles fires were associated with “major adverse health outcomes,” according to the study, extending beyond respiratory illness, highlighting the need for further research into both short- and long-term health risks from wildfire smoke exposure.
As wildfires continue to grow more frequent and intense, the study adds to mounting evidence that smoke exposure poses risks well beyond the burn zone.
The January wildfires burned from Santa Monica to Malibu and caused an estimated $250 to $275 billion in damages, according to AccuWeather experts.
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