Important but Overlooked Reactive Organic Carbon (ROC) Air Pollution From Permafrost Wildfires in Canada

Canadian permafrost wildfires, characterized by surface flaming and deep organic soil smoldering, emit complex suites of volatile organic compounds (VOCs). These emissions include air toxics that pose substantial public health risks and fuel secondary pollution, yet remain understudied. We quantified VOC emissions from the record‐setting 2023 wildfires using three inventories (GFED, GFAS, QFED) and assessed air quality impacts via GEOS‐Chem simulations and in situ observations. VOC emissions amount to ∼15 ± 8 TgC, just ∼2% of inorganic carbon. Despite this small fraction, their impacts are significant: simulated concentrations increase by 2–5 μg m −3 for benzene and 5–35 μg m −3 for formaldehyde and acetaldehyde during the fire season. Organic aerosols account for ∼60%–80% of the persistent record‐high PM 2.5 during the season. These findings highlight the distinct role of high‐latitude permafrost wildfires in driving regional reactive organic carbon (ROC) pollution and provide a framework to address interdisciplinary Earth science challenges.