清华大学赵斌教授团队的一项最新研究提出了野火排放物中二次有机气溶胶的形成因长期老化而增强。2024年1月9日出版的《自然—地球科学》发表了这项成果。

研究人员开发了一个氧化模型，在前驱水平上模拟了野火有机排放物在整个挥发范围内的老化，并整合了来自单一物种老化和野火排放老化实验以及现场羽流观测的见解，以限制野火有机气溶胶的长期老化。该模型捕捉到了野火老化实验中有机气溶胶质量(2-8倍)和氧碳比(1-4倍)的增加。

研究模型调和了长期以来对二次有机气溶胶形成幅度的实地观测和实验室观测之间的差异。该模型表明，排放驱动的前体对二次有机气溶胶的贡献有很大的变化，这种变化随着长期老化而进一步演变。估计全球野火二次有机气溶胶产量((每年139±34 Tg)远远高于先前忽略或未充分限制长期老化的研究。

据介绍，野火烟雾主要由有机气溶胶组成，其对空气质量、气候和人类健康有着深远影响。由于二次有机气溶胶的形成和老化，野火有机气溶胶在长时间的光化学氧化过程中发生演变，其大小和性质发生了实质性的变化。然而，由于复杂有机排放物具有明显的老化行为，野火有机气溶胶的长期老化存在较大的不确定性。

附：英文原文

Title: Formation of secondary organic aerosol from wildfire emissions enhanced by long-time ageing

Author: He, Yicong, Zhao, Bin, Wang, Shuxiao, Valorso, Richard, Chang, Xing, Yin, Dejia, Feng, Boyang, Camredon, Marie, Aumont, Bernard, Dearden, Abraham, Jathar, Shantanu H., Shrivastava, Manish, Jiang, Zhe, Cappa, Christopher D., Yee, Lindsay D., Seinfeld, John H., Hao, Jiming, Donahue, Neil M.

Issue&Volume: 2024-01-09

Abstract: Wildfire smoke, consisting primarily of organic aerosols, has profound impacts on air quality, climate and human health. Wildfire organic aerosol evolves over long-time photochemical oxidation due to the formation and ageing of secondary organic aerosol, which substantially changes its magnitude and properties. However, there are large uncertainties in the long-time ageing of wildfire organic aerosol because of the distinct ageing behaviours of the complex organic emissions. Here we developed an oxidation model that simulates the ageing of wildfire organic emissions in the full volatility range on a precursor level and integrated insights from single-species ageing and wildfire emissions ageing experiments and field plume observations to constrain the long-time ageing of wildfire organic aerosol. The model captured the enhancement of organic aerosol mass (2–8 times) and oxygen-to-carbon ratio (1–4 times) in the wildfire ageing experiments. It also reconciled a long-standing discrepancy between field and laboratory observations of the magnitude of secondary organic aerosol formation. The model indicated large emissions-driven variations in precursor contributions to secondary organic aerosol, which further evolve with long-time ageing. The estimated global wildfire secondary organic aerosol production (139±34Tgper year) was much higher than previous studies omitting or under-constraining long-time ageing.

DOI: 10.1038/s41561-023-01355-4

Source: https://www.nature.com/articles/s41561-023-01355-4