Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Guangdong Provincial Observation and Research Station for Coastal Atmosphere and Climate of the Greater Bay Area, Shenzhen 518055, China.
Environ Sci Technol. 2024 Sep 17;58(37):16507-16516. doi: 10.1021/acs.est.4c03279. Epub 2024 Sep 2.
Ultrafine particles (UFPs) dominate the atmospheric particles in number concentration, impacting human health and climate change. However, existing studies primarily rely on mass-based approaches, leading to a restricted understanding of the number-based and chemically resolved health effects of atmospheric UFPs. In this study, we utilized a high-mass-resolution single-particle aerosol mass spectrometer to investigate the online chemical composition and number size distribution of ultrafine, fine, and coarse particles during the summertime in urban Shenzhen, China. Human respiratory deposition dose assessments of particles with varying chemical compositions were further conducted by a respiratory deposition model. The results showed that during our observation, particles containing elemental carbon (EC) were the dominant components in UFPs (0.05-0.1 μm). Compared to fine and coarse particles, UFPs can deposit more deeply into the respiratory tract with a daily dose of ∼2.08 ± 0.67 billion particles. Among the deposited UFPs, EC-cluster particles constituted ∼85.7% in number fraction, accounting for a daily number dose of ∼1.78 billion particles, which poses a greater impact on human health. Simultaneously, we found discrepancies in the chemically resolved particle depositions among number-, surface area-, and mass-based approaches, emphasizing the importance of an appropriate metric for particle health-risk evaluation.
超细颗粒（UFPs）在数量浓度上主导着大气颗粒，对人类健康和气候变化都有影响。然而，现有的研究主要依赖于基于质量的方法，这导致对大气 UFPs 的基于数量和化学解析的健康影响的理解受到限制。在这项研究中，我们利用高质量分辨率的单颗粒气溶胶质谱仪，在中国城市深圳的夏季，在线研究了超细、细和粗颗粒的化学组成和数量大小分布。我们还通过呼吸沉积模型进一步评估了具有不同化学成分的颗粒的人体呼吸沉积剂量。结果表明，在我们的观测期间，含有元素碳 (EC) 的颗粒是 UFPs（0.05-0.1μm）的主要成分。与细颗粒和粗颗粒相比，UFPs 可以更深地沉积到呼吸道中，每天的剂量约为 20.8±0.67 亿个颗粒。在沉积的 UFPs 中，EC 团簇颗粒在数量分数中占约 85.7%，每天的数量剂量约为 17.8 亿个颗粒，对人体健康的影响更大。同时，我们发现基于数量、表面积和质量的方法在化学解析的颗粒沉积方面存在差异，这强调了为颗粒健康风险评估选择适当指标的重要性。
