PM_2.5 is one of major pollutants emitted from forest fires. High PM_2.5 concentration not only affects short-term human respiration health, but also poses a long-term threat to human cardiopulmonary functionality. Therefore, it is of great importance to quantitatively assess the PM_2.5 released by forest combustion in forest fire studies. In this study we examine relationships between the PM_2.5 concentration and environment and fuel characteristics laboratory experiments. In the experiments, fuel beds with controlled moisture contents and loads were first built; then 144 ignition experiments were conducted for various combinations of wind speeds using a wind tunnel device. Fire behavior characteristics and PM_2.5 concentrations released from fuel combustion were measured and analyzed. The experimental results show that the relationship between fire characteristics, fire intensity and the influencing factors of wind speed, fuel moisture content, and fuel load can be explained by the fundamental theory of forest combustion. Although PM_2.5 concentration rises with the increase of wind speed, the decrease of fuel moisture content, and the increase of fuel load, there appears to be a fuel load threshold for a given combination of wind speed and fuel moisture content that the increase of PM_2.5 concentration decelerates quickly after the load passes the threshold value. After screening fire behavior characteristics that affect PM_2.5 concentration, we found that fire line intensity and flame width are the ones with the strongest association with the concentration. With flame width as independent variable, we have built two regression models to predict PM_2.5 and fire line intensity which are treated as dependent variable; the models have high accuracy with R² = 0.92 for predicting PM_2.5 and R² = 0.97 for predicting fire line intensity. Study results can be used as reference to protect the health of forest fire fighters, and can be helpful for forest fire smoke management.

PM _2.5是森林火灾排放的主要污染物之一。PM _2.5浓度过高不仅会短期影响人体呼吸健康，还会对人体心肺功能构成长期威胁。_{因此，定量评估森林燃烧释放的PM 2.5}在森林火灾研究中具有重要意义。在本研究中，我们研究了 PM _2.5浓度与环境和燃料特性实验室实验之间的关系。在实验中，首先建造了控制含水量和负载的燃料床；然后利用风洞装置对各种风速组合进行了144次点火实验。测量并分析了火灾行为特征和燃料燃烧释放的 PM _2.5浓度。实验结果表明，火灾特征、火灾强度与风速、可燃物含水量、可燃量影响因素之间的关系可以用森林燃烧的基本理论来解释。尽管 PM _2.5浓度随着风速的增加、燃油水分含量的减少和燃油负载的增加而上升，但对于给定的风速和燃油水分含量的组合，似乎存在一个燃油负载阈值，即 PM 的增加_2.5负载超过阈值后浓度迅速减速。通过筛选影响PM _2.5浓度的火灾行为特征，我们发现火线强度和火焰宽度与浓度的相关性最强。以火焰宽度为自变量，建立两个回归模型来预测PM _2.5和火线强度，并将其作为因变量；该模型具有很高的准确度， 预测 PM _{2.5 的R} ² = 0.92 和 预测火线强度的R ^{2 = 0.97。}研究结果可为保护森林消防人员的健康提供参考，并对森林火灾烟气管理有所帮助。