School of Forestry, Northeast Forestry University, Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Harbin, 150040, China.
School of Forestry, Northeast Forestry University, Key Laboratory of Sustainable Forest Ecosystem Management, Ministry of Education, Harbin, 150040, China.
Environ Pollut. 2021 Oct 15;287:117282. doi: 10.1016/j.envpol.2021.117282. Epub 2021 May 7.
High concentration particulate matter 2.5 released from forest fires, in addition to direct burns and asphyxia, PM is one of the main pollutants which threaten the safety of forest fire fighter. Therefore, to assess spatial distribution of PM, a simulation study was conducted. Fuel beds with different moisture contents and loads were constructed. 144 times burning experiments were carried out under different wind speeds by using wind tunnel device. PM particles at different spatial points were collected and calculated. The results show that, in the two of three variables interaction between wind speed, fuel load, and, except fuel moisture content, wind speed and fuel load are positively correlated with the PM concentrations. From PM concentration which collected at each point in the horizontal and vertical directions, the overall trend is that PM concentration increases along the horizontal downwind direction (C and D higer than A and B) and the vertical upward direction (A and C higer than B and D) Based on BP neural network, the spatial distribution model of PM concentration with single hidden layer was established. The prediction accuracy of modeling samples and validation samples is balanced when hidden layer node is 5. This study will help to make reference for PM occupational exposure standards, forest fire smoke management and forest fire management in China.
森林火灾产生的高浓度颗粒物 2.5 除了直接烧伤和窒息外，颗粒物也是威胁森林消防人员安全的主要污染物之一。因此，为了评估颗粒物的空间分布，进行了模拟研究。构建了具有不同水分含量和负荷的燃料床。使用风洞装置在不同风速下进行了 144 次燃烧实验。在不同的空间点收集和计算了 PM 颗粒。结果表明，在风速、燃料负荷和除燃料水分含量之外的三个变量的两个交互作用中，风速和燃料负荷与 PM 浓度呈正相关。从水平和垂直方向上每个点收集的 PM 浓度来看，整体趋势是 PM 浓度沿顺风方向（C 和 D 高于 A 和 B）和垂直向上方向（A 和 C 高于 B 和 D）增加。基于 BP 神经网络，建立了具有单隐藏层的 PM 浓度空间分布模型。当隐藏层节点为 5 时，建模样本和验证样本的预测精度平衡。本研究将有助于为中国的 PM 职业暴露标准、森林火灾烟雾管理和森林火灾管理提供参考。
