Riss Calvin S, Faulstich Sam D, Reuther Patrick S, Metcalf William J, Darrow Lyndsey A, Holmes Heather A, Strickland Matthew J
School of Public Health, University of Nevada, Reno, United States.
Department of Chemical Engineering, University of Utah, United States.
Environ Int. 2025 Jul;201:109577. doi: 10.1016/j.envint.2025.109577. Epub 2025 Jun 3.
Wildland fire smoke is a significant source of PM pollution in the western United States, with varying chemical composition and toxicity depending on fire characteristics.
We analyzed emergency department and urgent care visits in the Reno/Sparks, Nevada region during fire seasons (July-September) from 2012 to 2019. Wildland fire smoke PM concentrations were determined using a novel approach that combined EPA monitor data, atmospheric dispersion modeling, fire emissions inventories, and Bayesian time-series modeling to estimate daily fire-specific smoke PM concentrations. Distributed lag models were used to estimate associations between total smoke PM concentrations, as well as smoke PM concentrations classified by fire intensity and fuel type, and daily counts of 11 cardiorespiratory visit outcome groups.
We observed positive lag-specific associations between total smoke PM concentrations (per 10 µg/m increase) and visits for asthma exacerbation (Lag 0 RR: 1.040; 95 %CI: 1.006, 1.075), cardiovascular disease (Lag 3 RR: 1.015; 95 % CI: 0.999, 1.032), and cardiac dysrhythmia (Lag 3 RR: 1.029; 95 % CI:1.012, 1.047). Elevated cumulative associations were also observed between total smoke PM and asthma exacerbation (Lag 0-4 RR: 1.066; 95 % CI: 1.005, 1.131), unspecified respiratory disorder (Lag 0-6 RR: 1.046; 95 % CI 0.993, 1.103), and dysrhythmia (Lag 0-5 RR: 1.072; 95 % CI: 1.018, 1.129). Visits for asthma exacerbation and unspecified respiratory disorder were more strongly associated with smoke from high intensity fires, whereas visits for dysrhythmia were more associated with smoke from low intensity fires. By fuel type, forest fire smoke was most strongly associated with increased asthma exacerbation, and visits for dysrhythmia were most strongly associated with smoke from shrub/scrub fires.
This study provides novel evidence that wildland fire intensity and fuel type may influence the relationship between smoke exposure and specific health outcomes, with implications for public health messaging and land management strategies.
在美国西部，野火烟雾是细颗粒物污染的一个重要来源，其化学成分和毒性因火灾特征而异。
我们分析了2012年至2019年火灾季节（7月至9月）内，内华达州里诺/斯帕克斯地区的急诊科和紧急护理就诊情况。采用一种新方法来确定野火烟雾中的细颗粒物浓度，该方法结合了美国环境保护局（EPA）的监测数据、大气扩散模型、火灾排放清单以及贝叶斯时间序列模型，以估算每日特定火灾的烟雾细颗粒物浓度。使用分布滞后模型来估计总烟雾细颗粒物浓度，以及按火灾强度和燃料类型分类的烟雾细颗粒物浓度，与11个心肺就诊结果组的每日就诊次数之间的关联。
我们观察到总烟雾细颗粒物浓度每增加10微克/立方米，与哮喘加重就诊（滞后0相对危险度：1.040；95%置信区间：1.006，1.075）、心血管疾病就诊（滞后3相对危险度：1.015；95%置信区间：0.999，1.032）以及心律失常就诊（滞后3相对危险度：1.029；95%置信区间：1.012，1.047）之间存在特定滞后的正相关。在总烟雾细颗粒物与哮喘加重就诊（滞后0 - 4相对危险度：1.066；95%置信区间：1.005，1.131）、未明确的呼吸系统疾病就诊（滞后0 - 6相对危险度：1.046；95%置信区间：0.993，1.103）以及心律失常就诊（滞后0 - 5相对危险度：1.072；95%置信区间：1.018，1.129）之间也观察到累积关联增强。哮喘加重就诊和未明确的呼吸系统疾病就诊与高强度火灾产生的烟雾关联更强，而心律失常就诊与低强度火灾产生的烟雾关联更强。按燃料类型来看，森林火灾烟雾与哮喘加重就诊增加的关联最为强烈，心律失常就诊与灌木/矮树丛火灾产生的烟雾关联最为强烈。
本研究提供了新的证据，表明野火强度和燃料类型可能会影响烟雾暴露与特定健康结果之间的关系，这对公共卫生信息传递和土地管理策略具有启示意义。
