The Trade-offs\nbetween Wildfires and Prescribed Fires:\nA Case Study for 2016 Gatlinburg Wildfires

Prescribed burning is an effective land management tool\nthat provides\na range of benefits, including ecosystem restoration and wildfire\nrisk reduction. However, prescribed fires, just like wildfires, introduce\nsmoke that degrades air quality. Furthermore, while prescribed fires\nhelp manage wildfire risk, they do not eliminate the possibility of\nwildfires. It is therefore important to also evaluate fire and smoke\nimpacts from wildfires that may occur after a prescribed burn. In\nthis study, we developed a framework for understanding the air quality\nand health related trade-offs between wildfires and prescribed fires\nby simulating a set of counterfactual scenarios including wildfires,\nprescribed fires, and postprescribed burn wildfires. We applied this\nframework to the case of the Gatlinburg wildfire and found that emissions\nfrom prescribed burns and subsequent wildfire were slightly lower\nthan those from the wildfire itself. This reduction resulted in lower\ndaily average concentrations and exposures of PM<sub>2.5</sub>, O<sub>3</sub>, and NO<sub>2</sub>. Even considering the possibility of\na postprescribed burn wildfire, prescribed fires reduced population-weighted\ndaily average PM<sub>2.5</sub>, daily maximum 8-h average O<sub>3</sub>, and 1-h maximum NO<sub>2</sub> concentrations. In Sevier County,\nTennessee where the wildfire occurred, these reductions reached 5.28\nμg/m<sup>3</sup>, 0.18 ppb, and 1.68 ppb, respectively. The\nprescribed fires also reduced the person-days smoke exposures from\nthe wildfire. Our results suggest that although prescribed fires cannot\neliminate the air quality impacts of wildfires, they can greatly reduce\nsmoke exposure in downwind areas distant from the burn sites.