Wildfires are a significant threat to human health, in part through degraded air quality. Prescribed burning can reduce wildfire severity but can also lead to an increase in air pollution. The complexities of fires and atmospheric processes lead to uncertainties when predicting the air quality impacts of fire and make it difficult to fully assess the costs and benefits of an expansion of prescribed fire. By modeling differences in emissions, surface conditions, and meteorology between wildfire and prescribed burns, we present a novel comparison of the air quality impacts of these fire types under specific scenarios. One wildfire and two prescribed burn scenarios were considered, with one prescribed burn scenario optimized for potential smoke exposure. We found that PM_2.5 emissions were reduced by 52%, from 0.27 to 0.14 Tg, when fires burned under prescribed burn conditions, considerably reducing PM_2.5 concentrations. Excess short-term mortality from PM_2.5 exposure was 40 deaths for fires under wildfire conditions and 39 and 15 deaths for fires under the default and optimized prescribed burn scenarios, respectively. Our findings suggest prescribed burns, particularly when planned during conditions that minimize smoke exposure, could be a net benefit for the impacts of wildfires on air quality and health.

中文翻译：

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加州野火和规定烧伤案例研究：PM2.5 排放、浓度及其对人类健康的影响

野火对人类健康构成重大威胁，部分原因是空气质量下降。规定的燃烧可以减轻野火的严重程度，但也可能导致空气污染加剧。火灾和大气过程的复杂性导致预测火灾对空气质量影响时存在不确定性，并且难以全面评估规定火灾扩大的成本和效益。通过对野火和规定燃烧之间的排放、地表条件和气象差异进行建模，我们对特定情景下这些火灾类型对空气质量的影响进行了新颖的比较。考虑了一场野火和两种规定的燃烧场景，其中一种规定的燃烧场景针对潜在的烟雾暴露进行了优化。我们发现，当火在规定的燃烧条件下燃烧时，PM _2.5排放量减少了 52%，从 0.27 Tg 降至 0.14 Tg，大大降低了 PM _2.5浓度。在野火条件下，PM _2.5暴露造成的短期超额死亡率分别为 40 人死亡，在默认和优化规定燃烧情景下的火灾分别为 39 人和 15 人死亡。我们的研究结果表明，规定的烧伤，特别是在最大限度地减少烟雾暴露的情况下计划进行的烧伤，可能会对野火对空气质量和健康的影响产生净效益。