PM_2.5 particles are extremely complicated, containing hundreds of organic, inorganic, and biological pollutants, and the components of PM_2.5 vary with time and region, making it difficult for researchers to determine the exact cause of PM_2.5-induced toxicity. Al³⁺ is a common metal content of PM_2.5. However, no data on the effect of Al³⁺ attributed to the cytotoxicity of PM_2.5 is available until now. Herein, we adopted a reductionism approach to synthesize a PM_2.5 model particle library including 16 materials with the core of carbon nanoparticles loaded with different metals, namely, Cr(VI), Pb²⁺, Zn²⁺, and Al³⁺, to investigate the effects of Al³⁺ on PM_2.5-induced cytotoxicity. Results indicated that the main physicochemical characteristics of the model particles were close to those of real PM_2.5 particles. Then, using this PM_2.5 model particle library, the influence of Al³⁺ on the PM_2.5-induced cytotoxic effect was determined. Cell assay results indicated that the toxic effect of PM_2.5 toward human bronchial epithelial cells (16HBE) varied for different adsorbed pollutants at environmentally relevant levels. It was found that the content of Al³⁺ alleviated the cytotoxic effect of PM_2.5 particles due to the decrease in intracellular reactive oxygen species (ROS) production. This study presents a meaningful method to study the cytotoxicity and mechanisms of specific components in complex PM_2.5 particles and these findings have implications for revealing the enormous deviations of toxicity of PM_2.5 particles in different periods and locations.

PM _2.5颗粒极其复杂，包含数百种有机，无机和生物污染物，PM _2.5的成分随时间和地区而变化，这使研究人员难以确定PM _2.5诱导的毒性的确切原因。Al ³⁺是PM _2.5中常见的金属含量。然而，到目前为止，尚无关于归因于PM _2.5的细胞毒性的Al ³⁺效应的数据。在本文中，我们采用还原论方法来合成PM _2.5模型颗粒库，该模型包含16种材料，其中碳纳米颗粒的核心负载有不同的金属，即Cr（VI），Pb 2 ⁺，Zn²⁺和Al ³⁺，以研究Al ³⁺对PM _2.5诱导的细胞毒性的影响。结果表明，模型颗粒的主要理化特性与真实的PM _2.5颗粒相近。然后，使用该PM _2.5模型粒子库，确定Al ³⁺对PM _2.5诱导的细胞毒性作用的影响。细胞测定结果表明，PM _2.5对人支气管上皮细胞（16HBE）的毒性作用在环境相关水平上因不同的吸附污染物而异。发现Al ³⁺的含量减轻了PM的细胞毒性作用_2.5颗粒是由于细胞内活性氧（ROS）产量减少所致。这项研究提供了一种有意义的方法来研究复杂的PM _2.5颗粒中特定成分的细胞毒性和机理，这些发现对于揭示PM _2.5颗粒在不同时期和位置的毒性的巨大偏差具有启示意义。