大兴安岭5种乔木树种燃烧释放PM2.5中水溶性元素特性

采用自主设计的生物质燃烧实验装置，在不同燃烧状态（明燃、阴燃）下，对大兴安岭林区5种典型乔木树种的不同部位（枝、叶、皮）燃烧释放PM_2.5中的水溶性元素特性进行研究.结果显示，不同树种间PM_2.5的排放因子差异显著，排放范围为（2.408±0.854）~（9.227±1.172）g/kg.5种乔木树种燃烧释放PM_2.5中主要检测到Mg、Ca、K等16 种元素，其中Ca、K、Zn、Mg 4种元素的排放因子明显大于其它元素.不同树种间元素排放因子差异较大，针叶树的排放因子一般高于阔叶树.除Cd元素外，不同器官间排放的元素总量无明显差异.不同树种不同器官燃烧释放PM_2.5中水溶性元素的占比顺序较为一致，其中Ca、K、Zn和Mg 4种元素的排放因子在枝、叶、皮中均较高.此外，燃烧状态对元素排放特征影响较大，Li、Mg、Ca等7种元素的排放因子均表现为明燃显著高于阴燃.

Characteristics of water-soluble elements in PM2.5 released from the combustion of five tree species in the Greater Xing'an Mountains

A self-designed biomass combustion device was used to analyze the water-soluble elements of PM_2.5 released by the combustion of different organs (branches, leaves and bark) of five typical tree species in the Greater Xing'an Mountains under different combustion conditions (flaming and smoldering). The results showed that the emission factors (EF) of PM_2.5 significantly varied among different tree species, and the emission rate ranged from (2.408±0.854) to (9.227±1.172)g/kg. Mg, Ca, K and 11 other ionic species were detected in the PM_2.5 released by five tree species, of which the EFs of Ca, K, Zn and Mg were significantly higher than other ionic species. The EFs from conifers were higher than hardwood species. Except for Cd, no significant difference was identified in the total emission of ionic species among various organs of five tree species. The proportions of ionic species in PM_2.5 released from different organs was generally consistent among five tree species, of which Ca、K、Zn and Mg were four dominant ionic species in branch, leaf and bark. In addition, emissions of ionic species were significantly influenced by the combustion condition, and the EFs of Li, Mg, Ca and four other ionic species were significantly higher under flaming than smoldering.