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林业科学 ›› 2019, Vol. 55 ›› Issue (7): 187-196.doi: 10.11707/j.1001-7488.20190721

• 研究简报 • 上一篇    下一篇

杉木枯落物燃烧释放污染物特征及PM2.5成分分析

鞠园华, 马祥庆, 郭林飞, 马远帆, 蔡奇均, 郭福涛   

  1. 福建农林大学林学院 海峡两岸红壤区水土保持协同创新中心 福州 350002
  • 收稿日期:2017-12-26 修回日期:2018-04-12 出版日期:2019-07-25 发布日期:2019-08-16
  • 基金资助:
    国家自然科学基金项目(31770697,31400552);福建农林大学杰出青年基金项目(xjq201613);福建农林大学国际科技与合作交流项目(KXB16008A)。

Characteristics of Pollutants Released by Combustion of Chinese Fir Litterfall and PM2.5 Composition Analysis

Ju Yuanhua, Ma Xiangqing, Guo Linfei, Ma Yuanfan, Cai Qijun, Guo Futao   

  1. College of Forestry, Fujian Agriculture and Forestry University Collaborative Innovation Center of Soil and Water Conservation in Red Soil Region of the Cross-Strait Fuzhou 350002
  • Received:2017-12-26 Revised:2018-04-12 Online:2019-07-25 Published:2019-08-16

摘要: [目的]探究杉木人工林枯落物在不同燃烧状态时的气态及颗粒态污染物排放特征,并提取、测定细颗粒物(PM2.5)污染物的化学成分,揭示林火及林地清理等对杉木枯落物分解、养分循环和大气环境的影响。[方法]分别以杉木人工林枯落物中的叶、枝、皮、干4种主要组分为研究对象,运用自主设计的生物质模拟燃烧系统,采用室内模拟燃烧试验,分析阴燃和明燃2种不同燃烧状态不同枯落物组分释放的气态污染物和PM2.5特征及差异。采用德国Elementar元素分析仪,测定PM2.5中的碳质成分;采用超声提取-离子色谱和ICP/MS技术,测定PM2.5中的水溶性离子和水溶性无机元素。[结果]基于杉木枯落物燃烧时的实时测定,CO2、CO、NOx、CxHy、PM2.5的排放因子(EF,单位质量燃料在燃烧后产生的污染物质量)变化范围在阴燃条件下分别是1001.4~1364.5、202.3~358.8、0.53~3.09、23.17~53.07、5.11~38.37 g·kg-1,而明燃时分别为1092.4~1520.7、115.1~242.6、0.16~1.96、1.21~41.50、2.58~21.07 g·kg-1。此外,提取测定PM2.5成分的结果表明,颗粒物主要由碳质组分、水溶性离子及少量水溶性无机元素等组成。其中碳质组分含量最大,占50%以上,有机碳(OC)和元素碳(EC)平均质量分数分别为43.29%和12.91%;PM2.5中测定出6种阳离子(Li+、Na+、NH4+、K+、Mg2+、Ca2+)和5种阴离子(F-、Cl-、NO2-、SO42-、NO3-),总水溶性离子占10%~33%,阴燃以Cl-、K+、Ca2+、SO42-为主要组分,明燃以K+、Cl-、SO42-、Na+为主;PM2.5中提取测定出16种无机元素,分别为K、Ca、Na、Mg、P、Zn、Al、Cu、As、Ba、Cr、Fe、Mn、Cd、Li、Pb,含量极少,仅占PM2.5的0.04%~0.58%,其中K、Ca、Na、Mg、P、Zn为主要元素成分,占总无机元素的96.8%~98.8%。[结论]在不同燃烧状态下,杉木枯落物释放各污染物的排放因子存在显著差异,除CO2外的其他污染物排放因子在阴燃时显著高于明燃;在同一燃烧状态时,杉木枯落物不同组分的CO、CO2、NOx、CxHy和PM2.5等污染物的排放因子也存在显著差异。杉木枯落物燃烧排放的PM2.5主要由碳质组分、水溶性离子及少量无机元素等成分组成,阴燃时的各成分排放因子整体表现为高于明燃时。

关键词: 杉木, 枯落物, 燃烧状态, 排放特征, PM2.5

Abstract: [Objective] The objective of this study was to investigate the emission characteristics of gaseous and particulate pollutants from litterfall of Chinese fir plantation under different combustion states, and to extract and determine the chemical composition of PM2.5, in order to reveal the impact of forest fire and forest clearing on litterfall decomposition, nutrient cycling, and atmosphere environment.[Method] Four main components of leaves, branches, barks and stems of litterfall in Chinese fir plantation were selected as research materials. With a self-designed biomass simulation combustion system, an indoor simulation combustion experiment was conducted to analyze the characteristic variation of gaseous pollutants and PM2.5 released by different litter components under smoldering and flaming states. The carbonaceous components in PM2.5 were determined by an Elementar elemental analyzer (produced in Germany). The contents of water-soluble ions and water-soluble inorganic elements in PM2.5 were identified by ultrasonic extraction-ion chromatography and ICP/MS techniques.[Result] The result showed that the emission factors of CO2, CO, NOx, CxHy and PM2.5 varied in the range of 1 001.4-1 364.5,202.3-358.8, 0.53-3.09, 23.17-53.07 and 5.11-38.37 g·kg-1 in the smoldering state, respectively and varied in the range of 1 092.4-1 520.7, 115.1-242.6, 0.16-1.961,1.21-41.50, 2.58-21.07 g·kg-1 in the flaming state. In addition, the components of PM2.5 were extracted and determined. The result showed that PM2.5 contained carbonaceous components, water-soluble ions and a small amount of water-soluble inorganic elements. The content of carbonaceous components occupied the largest proportion, accounting for more than 50% of PM2.5. The average mass fractions of organic carbon (OC) and elemental carbon (EC) were 43.29% and 12.91% respectively. Six cations (Li+, Na+, K+, NH4+, Mg2+, and Ca2+) and five anions (F-, Cl-, NO2-, SO42- and NO3-) were identified in PM2.5, and the total water-soluble ions accounted for 10% -33% of PM2.5. Cl-, K+, Ca2+, and SO42- were determined as main water-soluble ions in smoldering state and K+, Cl-, SO42-, and Na+ were main water-soluble ions in flaming stage. Sixteen inorganic elements (K, Ca, Na, Mg, P, Zn, Al, Cu, As, Ba, Cr, Fe, Mn, Cd, Li and Pb) were extracted from PM2.5, but accounting for only 0.04%-0.58% of PM2.5, of which K, Ca, Na, Mg, P and Zn were the main elements, accounting for 96.8% to 98.8% of the total inorganic elements.[Conclusion] The same litterfall type under different combustion states showed significant differences in the emission factors of pollutants. Except CO2, the emissions of other pollutants in smoldering state were significantly higher than those in flaming state. In addition, there existed significant variation exists in the emission factors of CO, CO2, NOx, CxHy and PM2.5 from different components of litterfall of Chinese fir plantation at the same combustion state. PM2.5 was mainly composed of carbonaceous components, water-soluble ions and a small amount of inorganic elements and other ingredients. Generally, the concentration of each component in PM2.5 in the smoldering state was higher than that in the flaming state.

Key words: Chinese fir, litterfall, combustion state, emission characteristics, PM2.5

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