About the study: Is exposure to wildfire-sourced fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM 2.5) associated with emergency department (ED) visits for migraine and other primary headache syndromes? In this case-crossover study of 997 701 ED visits in Alberta and Ontario, Canada, between 2010 and 2023, wildfire-sourced PM 2.5 was significantly associated with a 6% increase in ED visits for migraine and other primary headache syndromes. Associations were attenuated in the least materially and socially deprived areas, and no significant association was observed for PM 2.5 on nonwildfire days. These findings suggest that wildfire-sourced PM 2.5 may precede severe headache episodes requiring ED care.
Corresponding Author: Sabit Cakmak, PhD, Health Canada, Environmental Health Science sabit.cakmak@hc-sc.gc.ca .
10.1001/jamanetworkopen.2026.25015
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