典型树种挥发性有机物(VOCs)排放成分谱及排放特征

为研究典型树种的挥发性有机物（VOCs）排放特征，并获得基础排放速率，应用动态封闭式采样系统对毛果杨、北美枫香和马尾松的排放进行了实验室测量.利用热脱附-气相色谱-飞行质谱仪对排放样品进行定性和定量分析，包括异戊二烯、单萜烯、倍半萜烯、烷烃和烯烃，计算获得各树种VOCs排放速率及其排放谱特征.研究表明：毛果杨、北美枫香和马尾松的总VOCs排放速率分别为19.51、17.19和0.67μg/（g·h）.毛果杨的异戊二烯排放最高（18.51μg/（g·h）），占其总排放的94.86%；马尾松排放的异戊二烯仅占4.03%，单萜烯贡献最高，为49.09%；北美枫香的单萜烯排放速率最高，为0.84μg/（g·h）；3个树种排放的倍半萜烯占各自VOCs总排放的比重均较小（<1.5%）；各树种的烷烃排放强度高于倍半萜烯，部分化合物甚至高于异戊二烯和单萜烯的排放强度.反式-β-罗勒烯是毛果杨排放最多的单萜烯化合物，占其单萜烯总排放的99.84%；北美枫香排放的单萜烯主要以香桧烯和β-蒎烯为主；马尾松以α-蒎烯、香桧烯和β-蒎烯为主.石竹烯、葎草烯、δ-杜松烯和β-愈创木烯是主要的倍半萜烯物种.烷烃排放主要为C4和C5的化合物，特别是异丁烷和正丁烷；各树种排放的烯烃中，1-丁烯排放占比最高.

Biogenic emission profile of volatile organic compounds from poplar,sweetgum, and pine trees

In order to study the characteristics of biogenic volatile organic compounds (BVOCs) emission from typical trees and obtain their basic emission rates for each BVOC compound, a dynamic enclosed system was used to conduct laboratory measurements on poplar, sweetgum, and pine trees. BVOC compounds including isoprene, monoterpenes, sesquiterpenes, alkanes, and alkenes were analyzed by TD-GC-TOFMS. The normalized species-specific BVOC emission rates of three tree species were calculated and their emission profiles were investigated. The total BVOC emission rates of Populus trichocarpa, Liquidambar styraciflua, and Pinus massoniana were 19.51, 7.19, and 0.67μg/(g·h) (2086.91, 562.35, and 104.03μg/(m²·h)), respectively. Populus trichocarpa had the highest isoprene emission rate of 18.51μg/(g·h), contributing 94.86% to the total BVOC emissions. Pinus massoniana had a lower isoprene contribution (4.03%), but the highest monoterpenes contribution (49.09%. Liquidambar styraciflua had the highest monoterpenes emission rate of 0.84μg/(g·h). Sesquiterpenes contributed less than 1.5% to the total BVOC emissions for the three plants. The emission rates of alkanes for each tree species were generally higher than those of sesquiterpenes, and some were even higher than those of isoprene and monoterpenes. Trans-β-ocimene was the predominated monoterpene for Populus trichocarpa, accounting for 99.84% of its total monoterpene emissions. The monoterpenes emitted by Liquidambar styraciflua.was mainly composed by Sabinene and β-pinene. α-Pinene, sabinene, and β-pinene were observed as the dominated monoterpenes for Pinus massoniana. Trans-caryophyllene, humulene, δ-cadinene, and β-guaiene were prominent sesquiterpenes. Alkanes emitted from the three plants were mainly C4 and C5 compounds, of which particularly were isobutane and butane. 1-Butene was the most abundant alkene for all plants.