OT31: Fighting Fire With Fire - The Hidden Health Cost of Preventing Wildfires

Welcome back to Air Quality Matters and One Take, where we unpack the latest research shaping our understanding of indoor air and the built environment. This week, we're diving into one of the most complex and urgent environmental dilemmas of our time: the smoke from fires we set on purpose. The paper, Associations between PM2.5 from Prescribed Burning and Emergency Department Visits in 11 Southeastern US States by a team of researchers from Boston University, Georgia Tech, and other institutions, tackles a critical question: In our effort to prevent catastrophic wildfires through prescribed burning, are we creating a different, more chronic health problem from the smoke of these "good fires"? The Environmental Dilemma: Prescribed burning—intentionally setting smaller, controlled fires to clear underbrush—is one of our primary tools to fight the catastrophic wildfires made worse by climate change. But this tool has side effects: smoke containing fine particulate matter (PM2.5). The question is whether we're trading one health disaster for another. The Study: Researchers analyzed over 30 million emergency department visits from 11 southeastern US states over nearly a decade—a region where prescribed burning is common practice. Using sophisticated chemical transport models, they "tagged" PM2.5 in the air to identify which portions came specifically from prescribed fires, allowing them to isolate the health signal of just these controlled burns. The Surprising Findings: Yes, there is a link. On days with high levels of PM2.5 from prescribed fires, there was a statistically significant increase in emergency department visits for upper respiratory infections and, most notably, ischemic heart disease, which went up by about 6%. But here's the counter-intuitive part: For the classic signatures of smoke exposure—overall respiratory admissions, asthma, and COPD—they didn't find a statistically significant increase. This is what makes smoke from prescribed fires different from wildfire smoke. Why the Difference? The nature of the fires themselves. Wildfires are hot, intense, and chaotic, burning everything from the forest floor to the canopy. Prescribed burns are cooler and slower, designed to smolder through underbrush, grass, and leaf litter. This difference in what's burning and how it's burning creates a different chemical cocktail of smoke. Prescribed fire smoke tends to have lower concentrations of pollutants like carbon monoxide and polycyclic aromatic hydrocarbons (PAHs) compared to wildfire smoke. The Big Takeaway: Not all smoke is created equal. The health impact of PM2.5 is not just about the mass of particles in the air—it's about what those particles are made of, and it depends profoundly on the source. This research doesn't give us an easy answer. It doesn't say prescribed burning is safe or unsafe. Instead, it gives us a much more nuanced picture. It's a powerful reminder that there are no easy wins in environmental management—it's all a game of trade-offs. We're using a tool to reduce the risk of catastrophic wildfires, but that tool has its own health risks, and those risks are different. This kind of research is absolutely vital for land managers and public health officials because it helps them understand the specific health impacts of their decisions, allowing for more targeted warnings and a better, more honest conversation about the risks we're actually choosing to manage. Associations between PM2.5 from prescribed burning and emergency department visits in 11 Southeastern US states https://doi.org/10.1016/j.envint.2025.109770 The One Take Podcast in Partnership with SafeTraces and Inbiot Do check them out in the links and on the Air Quality Matters Website Chapters 00:00:00 Introduction: The Prescribed Burning Paradox 00:01:48 The Study Design: Tagging Smoke from Good Fires 00:02:54 The Findings: A Surprising Health Signal 00:04:02 Not All Smoke is Equal: The Chemistry Matters 00:05:32 The Big Takeaway: Environmental Trade-Offs and Honest Conversations 00:06:40 Closing: Thanks and Next Week