Effects of tropical wildfire behavior on fire emissions and subsequent impacts on PM2.5 and O3 levels
摘要
This study aims to explore the associations between wildfire behavior parameters and various emissions, analyze the impacts of these emissions on environmental PM2.5 and O3, and reveal the complex causal relationships between fire behavior and PM2.5 and O3 through emissions. The research focuses on three key regions: tropical America, tropical Africa, and tropical Asia. Using multi-output random forest and structural equation modeling, we analyzed the relationships between fire behavior parameters, emissions, and air quality indicators. The results show that: 1) there is a significant spatial correlation between fire behavior parameters and the aforementioned emissions, and this correlation exhibits different patterns in different tropical regions; 2) various pollutants emitted by fires have a significant impact on the formation of PM2.5 and O3, among which: in tropical Asia, the role of emissions such as NMVOCs, NOx, NH3, CH4, and SO2 is particularly prominent. In tropical America and Africa, NH3, N2O, and NMVOCs are the main influencing factors. The RF-MTL model demonstrated high predictive performance in these analyses, achieving R2 values of up to 0.87 for O3 in tropical Asia and 0.83 for PM2.5 in tropical America.; 3) the study not only confirms the role of fire behavior in the synergistic effect between PM2.5 and O3 but also reveals the key role of mediating factors such as N2O, NOx, and SO2 in the path of fire behavior affecting pollutants, where Fire Radiative Power (FRP) exerted a total positive effect of 0.366 on PM2.5 in tropical America and a total negative effect of − 0.594 in tropical Africa. The conclusions of this study provide important insights for understanding the impact of wildfire behavior on air quality and have significant reference value for formulating air quality management and wildfire control policies in different tropical regions.