Atmospheric evolution of emissions from a boreal forest fire: the formation of highly functionalized oxygen-, nitrogen-, and sulfur-containing organic compounds
Atmospheric evolution of emissions from a boreal forest fire: the formation of highly functionalized oxygen-, nitrogen-, and sulfur-containing organic compounds
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DOI：
10.5194/acp-21-255-2021
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发表时间：
2021-01-14
影响因子：
6.3
通讯作者：
Gentner, Drew R.
中科院分区：
文献类型：
--
作者：
Ditto, Jenna C.;He, Megan;Gentner, Drew R.
森林火灾是大气中活性气相和颗粒相有机化合物的主要贡献者。我们使用离线高分辨率串联质谱进行分子水平的气体和颗粒相化合物的物种形成，通过飞机从不断发展的北方森林火灾烟羽在加拿大萨斯喀彻温省。我们观察到了多种含有氧、氮和硫的多功能化合物（CHONS），其结构、形成和影响尚未得到充分研究。稀释校正的绝对离子丰度的颗粒相CHONS化合物增加羽年龄的一个因素为6.4在第一个4小时的顺风运输，和他们的相对贡献所观察到的功能化有机气溶胶（OA）混合物从19%增加到40%。稀释校正的绝对离子丰度的颗粒相化合物与硫化物官能团的羽年龄增加了13倍，其相对贡献观察到OA从4%增加到40%。硫化物存在于高达75%的CHONS化合物中，硫化物的增加伴随着环结合氮的增加;两者都随着CHONS患病率的增加而增加。一个复杂的混合物的中间和半挥发性的气相有机硫物种观察到的排放量从火灾和耗尽顺风，代表潜在的前体颗粒相CHONS化合物。这些结果表明，在还原硫物质存在下，由含氮和含氧生物质燃烧排放物形成CHONS。此外，它们强调了化学途径，这些途径也可能与住宅生物质燃烧和化石燃料使用导致的含氮和含硫有机化合物排放量增加的情况有关（例如，煤）。
Forest fires are major contributors of reactive gas- and particle-phase organic compounds to the atmosphere. We used offline high-resolution tandem mass spectrometry to perform a molecular-level speciation of gas- and particle-phase compounds sampled via aircraft from an evolving boreal forest fire smoke plume in Saskatchewan, Canada. We observed diverse multifunctional compounds containing oxygen, nitrogen, and sulfur (CHONS), whose structures, formation, and impacts are understudied. The dilution-corrected absolute ion abundance of particle-phase CHONS compounds increased with plume age by a factor of 6.4 over the first 4 h of downwind transport, and their relative contribution to the observed functionalized organic aerosol (OA) mixture increased from 19% to 40 %. The dilution-corrected absolute ion abundance of particle-phase compounds with sulfide functional groups increased by a factor of 13 with plume age, and their relative contribution to observed OA increased from 4% to 40 %. Sulfides were present in up to 75% of CHONS compounds and the increases in sulfides were accompanied by increases in ring-bound nitrogen; both increased together with CHONS prevalence. A complex mixture of intermediate- and semi-volatile gas-phase organic sulfur species was observed in emissions from the fire and depleted downwind, representing potential precursors to particle-phase CHONS compounds. These results demonstrate CHONS formation from nitrogen- and oxygen-containing biomass burning emissions in the presence of re-duced sulfur species. In addition, they highlight chemical pathways that may also be relevant in situations with elevated emissions of nitrogen- and sulfur-containing organic compounds from residential biomass burning and fossil fuel use (e.g., coal), respectively.