Scholarlink

<p>Elucidating the molecular-level evolution of organic aerosols (OA) is fundamental to understanding atmospheric chemistry and its climatic impacts, yet current analytical techniques are often constrained by thermal decomposition and fragmentation artifacts. In this study, we deployed a novel Vaporization Inlet for Aerosols coupled with a Vocus Proton Transfer Reaction Time-of-Flight Mass Spectrometer (VIA-PTR) during a wintertime field campaign in urban Beijing. The VIA-PTR exhibited high fidelity in molecular characterization, showing minimal thermal decomposition of dicarboxylic acid standards and robust agreement with co-located aerosol mass spectrometry for total OA (<i>R</i><sup>2</sup> = 0.88). On average, the VIA-PTR quantified 35% of the total OA mass, with mass closure reaching up to 60% during polluted episodes. Molecular analysis revealed that the particle-phase OA composition was dominated by low-molecular-weight, moderately oxygenated CHO compounds (~80%), such as small organic acids and ketones primarily driven by photochemical production. The system’s high temporal resolution enabled the detection of a transient, 10-minute biomass burning plume, identifying specific molecular signatures including catechol and guaiacol derivatives. Furthermore, positive matrix factorization (PMF) resolved six molecular-level OA factors, providing superior source insights compared to conventional bulk OA analysis. While the measured particle-phase fraction (<i>F</i><sub>p</sub>) of OA increased concurrently with pollution intensity and molecular oxygen content, traditional equilibrium partitioning models significantly underestimated the <i>F</i><sub>p</sub> of small oxygenated molecules. Our results highlight the VIA-PTR as a robust platform for real-time OA molecular speciation and underscore the need for improved gas-particle partitioning frameworks that incorporate molecular structure and complex pollution regimes in urban environments.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Molecular-level insights into organic aerosol evolution and gas-particle partitioning in Beijing using a vaporization inlet coupled with Vocus PTR-MS

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2026年7月11日

查看全文
  • Wei Zhou,
  • Rujing Yin,
  • Zijun Zhang,
  • Jian Zhao,
  • Siqi Zeng,
  • Hang Liu,
  • Yan Li,
  • Weiqi Xu,
  • Liu Yang,
  • Xi Chen,
  • Yunping Kan,
  • Xiaole Pan,
  • Zifa Wang,
  • Hong-Bin Xie,
  • Yele Sun

摘要

Elucidating the molecular-level evolution of organic aerosols (OA) is fundamental to understanding atmospheric chemistry and its climatic impacts, yet current analytical techniques are often constrained by thermal decomposition and fragmentation artifacts. In this study, we deployed a novel Vaporization Inlet for Aerosols coupled with a Vocus Proton Transfer Reaction Time-of-Flight Mass Spectrometer (VIA-PTR) during a wintertime field campaign in urban Beijing. The VIA-PTR exhibited high fidelity in molecular characterization, showing minimal thermal decomposition of dicarboxylic acid standards and robust agreement with co-located aerosol mass spectrometry for total OA (R2 = 0.88). On average, the VIA-PTR quantified 35% of the total OA mass, with mass closure reaching up to 60% during polluted episodes. Molecular analysis revealed that the particle-phase OA composition was dominated by low-molecular-weight, moderately oxygenated CHO compounds (~80%), such as small organic acids and ketones primarily driven by photochemical production. The system’s high temporal resolution enabled the detection of a transient, 10-minute biomass burning plume, identifying specific molecular signatures including catechol and guaiacol derivatives. Furthermore, positive matrix factorization (PMF) resolved six molecular-level OA factors, providing superior source insights compared to conventional bulk OA analysis. While the measured particle-phase fraction (Fp) of OA increased concurrently with pollution intensity and molecular oxygen content, traditional equilibrium partitioning models significantly underestimated the Fp of small oxygenated molecules. Our results highlight the VIA-PTR as a robust platform for real-time OA molecular speciation and underscore the need for improved gas-particle partitioning frameworks that incorporate molecular structure and complex pollution regimes in urban environments.