Institute of Surface-Earth Science, School of Earth System Science, Tianjin University, Tianjin 300072, China.
Scientific Research Academy of Guangxi Environment Protection, Nanning, Guangxi Zhuang Autonomous Region 530022, China.
Environ Sci Technol. 2024 Jun 25;58(25):10991-11002. doi: 10.1021/acs.est.3c10125. Epub 2024 Jun 3.
Peatland wildfires contribute significantly to the atmospheric release of light-absorbing organic carbon, often referred to as brown carbon. In this study, we examine the presence of nitrogen-containing organic compounds (NOCs) within marine aerosols across the Western Pacific Ocean, which are influenced by peatland fires from Southeast Asia. Employing ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in electrospray ionization (ESI) positive mode, we discovered that NOCs are predominantly composed of reduced nitrogenous bases, including CHN+ and CHON+ groups. Notably, the count of NOC formulas experiences a marked increase within plumes from peatland wildfires compared to those found in typical marine air masses. These NOCs, often identified as N-heterocyclic alkaloids, serve as potential light-absorbing chromophores. Furthermore, many NOCs demonstrate pyrolytic stability, engage in a variety of substitution reactions, and display enhanced hydrophilic properties, attributed to chemical processes such as methoxylation, hydroxylation, methylation, and hydrogenation that occur during emission and subsequent atmospheric aging. During the daytime atmospheric transport, aging of aromatic N-heterocyclic compounds, particularly in aliphatic amines prone to oxidation and reactions with amine, was observed. The findings underscore the critical role of peatland wildfires in augmenting nitrogen-containing organics in marine aerosols, underscoring the need for in-depth research into their effects on marine ecosystems and regional climatic conditions.
泥炭地野火大量向大气中释放吸收光的有机碳，通常被称为棕色碳。在这项研究中，我们研究了受东南亚泥炭地火灾影响的西太平洋海洋气溶胶中含氮有机化合物（NOC）的存在情况。我们采用电喷雾电离（ESI）正模式下的超高分辨率傅里叶变换离子回旋共振质谱（FT-ICR MS）发现，NOC 主要由含氮碱基组成，包括 CHN+和 CHON+基团。值得注意的是，与典型海洋气团中的 NOC 公式数量相比，泥炭地野火羽流中的 NOC 公式数量明显增加。这些 NOC 通常被鉴定为 N-杂环生物碱，是潜在的光吸收发色团。此外，许多 NOC 表现出热解稳定性，参与各种取代反应，并具有增强的亲水性，这归因于排放和随后的大气老化过程中发生的甲氧基化、羟基化、甲基化和氢化等化学过程。在白天的大气传输过程中，观察到芳香族 N-杂环化合物的老化，特别是在易氧化和与胺反应的脂肪族胺中。这些发现强调了泥炭地野火在增加海洋气溶胶中含氮有机物方面的重要作用，突显了深入研究它们对海洋生态系统和区域气候条件影响的必要性。
