福建省4种主要乔木枝叶燃烧含碳物质排放特性分析

森林可燃物燃烧释放的大量含碳物质对大气环境和生态系统碳平衡具有重要影响，揭示森林可燃物燃烧的含碳物质排放特性具有重要的科学意义.运用自主设计的生物质燃烧系统，模拟福建省4种主要乔木树种——马尾松、杉木、樟树、桉树的枝、叶燃烧，分析其在不同燃烧状态（阴燃、明燃）下含碳气体（CO、CO₂、C_xH_y）和PM_2.5的排放因子（分别以EF_CO2、EF_CO、EF_CxHy、EF_PM2.5表示）及PM_2.5中的碳质组分之间的差异性.结果表明，马尾松、杉木、樟树、桉树燃烧排放的含碳气体、PM_2.5的排放因子及PM_2.5的碳质组分在不同燃烧状态下差异较大，阴燃时EF_CO2、EF_CO、EF_CxHy、EF_PM2.5平均值在分别为（1 400.7±76.5）（297.6±16.2）（25.2±3.9）（23.9±4.3）g/kg，明燃时分别为（1 582.8±73.2）（253.6±16.1）（17.2±3.7）（8.4±2.8）g/kg，除CO₂外其他多为阴燃显著高于明燃.针叶树种（杉木、马尾松）枝、叶在阴燃时EF_PM2.5高于阔叶树种（樟树、桉树），而明燃时差异相对较小.PM_2.5中OC（有机碳）、EC（元素碳）、TC（OC+EC）的质量分数阴燃时分别为45.6%、12.0%、57.6%，明燃时分别为42.9%、17.6%、60.5%.EF_OC/EF_PM2.5、EF_EC/EF_PM2.5、EF_OC/EF_EC在两种燃烧状态下具有不同的特征，其特征值可作为区分不同燃烧源或不同燃烧状态的指标；EF_OC/EF_PM2.5在明燃和阴燃时差异不大，平均值分别为0.49、0.46；EF_EC/EF_PM2.5明燃显著高于阴燃，平均值分别为0.18、0.12；4种乔木的枝、叶燃烧的EF_OC/EF_EC明燃低于阴燃，平均值分别为2.59和4.01.在两种燃烧状态下OC与PM_2.5的排放因子均呈显著相关.研究显示，不同燃烧条件以及不同燃料燃烧对排放含碳物质具有显著影响. 

Carbon Emission Characteristics of Branch and Leaf of Four Tree Species in Fujian Province

Forest fuel combustion releases a large amount of carbonaceous components, significantly impacting atmospheric environment, carbon balance of ecosystem. It is important to reveal the emission characteristics of carbonaceous components from forest fuel combustion. The branches and leaves of four dominant tree species, Masson pine, Chinese fir, camphor, eucalyptus, were burned based on independent-designed biomass combustion system for analyzing the variation of emission factor of carbonaceous and fine particulate matters (PM_2.5) between tree species under different combustion conditions. The results showed that the emission factors of carbonaceous and PM_2.5 and the carbon content within PM_2.5 significantly varied among four tree species under different combustion status. The average emission factor of CO₂, CO, C_xH_y and PM_2.5 from four tree species are (1400.7±76.5), (297.6±16.2), (25.2±3.9) and (23.9±4.3)g/kg, respectively during smoldering combustion; correspondingly, the values are (1582.8±73.2), (253.6±16.1), (17.2±3.7) and (8.4±2.8)g/kg during flaming burning status. Except for CO₂, the emission factors of all other pollutants from smoldering burning are higher than that of flaming burning. The branch and leaf of coniferous trees emitted more PM_2.5 than broadleaf trees in the smoldering status; however, the difference is relatively small during flaming burning. The average mass fraction of organic carbon (OC), elemental carbon (EC) and the total carbon (TC, TC=OC+EC) of PM_2.5 during smoldering combustion were 45.6%, 12.0%, 57.6%, respectively and were 42.9%, 17.6% and 60.5% correspondingly during flaming combustion. The values of EF_OC/EF_PM2.5, EF_EC/EF_PM2.5 and EF_OC/EF_EC significantly varied between two different combustion condition, which can be used to differentiate the different combustion sources or different combustion condition. There is no significant difference in the ratio of EF_OC to EF_PM2.5 (EF_OC/EF_PM2.5) between smoldering (0.49) and flaming burning (0.46); However, the EF_EC/EF_PM2.5 in flaming burning (0.18) is significant higher than that of smoldering burning (0.12); EF_OC/EF_EC in flaming burning (2.59) is significant lower than that of smoldering burning (4.01). In addition, the emission factors of OC and PM_2.5 were significantly correlated between two combustion status. The study shows that different fuel combustion and different combustion conditions have significant effects on carbon containing substances.