Yan Yongxin, Nie Yan, Gao Xiaoshuai, Yan Xiaoyu, Ji Yuanyuan, Li Junling, Li Hong
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Department of Environmental Science and Engineering, Beijing University of Technology, Beijing 100124, China.
Toxics. 2025 Apr 19;13(4):318. doi: 10.3390/toxics13040318.
Atmospheric intermediate volatile organic compounds (IVOCs) are important precursors of secondary organic aerosols (SOAs), and in-depth research on them is crucial for atmospheric pollution control. This review systematically synthesizes global advancements in understanding IVOC sources, emissions characterization, compositional characteristics, ambient concentrations, SOA contributions, and health risk assessments. IVOCs include long-chain alkanes (C~C), sesquiterpenes, polycyclic aromatic hydrocarbons, monocyclic aromatic hydrocarbons, phenolic compounds, ketones, esters, organic acids, and heterocyclic compounds, which originate from primary emissions and secondary formation. Primary emissions include direct emissions from anthropogenic and biogenic sources, while secondary formation mainly results from radical reactions or particulate surface reactions. Recently, the total IVOC emissions have decreased in some countries, while emissions from certain sources, such as volatile chemical products, have increased. Ambient IVOC concentrations are generally higher in urban rather than in rural areas, higher indoors than outdoors, and on land rather than over oceans. IVOCs primarily generate SOAs via oxidation reactions with hydroxyl radicals, nitrate radicals, the ozone, and chlorine atoms, which contribute more to SOAs than traditional VOCs, with higher SOA yields. SOA tracers for IVOC species like naphthalene and β-caryophyllene have been identified. Integrating IVOC emissions into regional air quality models could significantly improve SOA simulation accuracy. The carcinogenic risk posed by naphthalene should be prioritized, while benzo[a]pyrene requires a combined risk assessment and hierarchical management. Future research should focus on developing high-resolution online detection technologies for IVOCs, clarifying the multiphase reaction mechanisms involved and SOA tracers, and conducting comprehensive human health risk assessments.
大气中的中等挥发性有机化合物（IVOCs）是二次有机气溶胶（SOAs）的重要前体物，对其进行深入研究对于大气污染控制至关重要。本综述系统地综合了全球在理解IVOCs来源、排放特征、组成特征、环境浓度、对SOAs的贡献以及健康风险评估等方面的进展。IVOCs包括长链烷烃（C~C）、倍半萜、多环芳烃、单环芳烃、酚类化合物、酮类、酯类、有机酸和杂环化合物，它们来源于一次排放和二次生成。一次排放包括人为源和生物源的直接排放，而二次生成主要源于自由基反应或颗粒物表面反应。最近，一些国家的IVOCs总排放量有所下降，而某些来源（如挥发性化学产品）的排放量有所增加。环境IVOC浓度一般在城市高于农村，室内高于室外，陆地高于海洋。IVOCs主要通过与羟基自由基、硝酸根自由基、臭氧和氯原子的氧化反应生成SOAs，其对SOAs的贡献比传统挥发性有机化合物更大，SOA产率更高。已确定了萘和β-石竹烯等IVOC物种的SOA示踪剂。将IVOC排放纳入区域空气质量模型可显著提高SOA模拟精度。应优先考虑萘带来的致癌风险，而苯并[a]芘需要进行综合风险评估和分级管理。未来的研究应侧重于开发IVOCs的高分辨率在线检测技术，阐明相关的多相反应机制和SOA示踪剂，并进行全面的人体健康风险评估。
