Environmental persistent free radicals (EPFRs) are new environmental health risk substances in the atmosphere, and their oxidative toxicity (OT) has not been strongly confirmed. In this study, the fugitive characteristics of EPFRs in road dust in a metropolitan city located in northwest China, and their potential oxidative toxicity were investigated. The results showed that the road dust contains Carbon-centered EPFRs with the mean mass concentration of (6.6 ± 5.0) × 10¹⁷ spins/g. EPFRs in road dust are degradable and have a half-life of 4.5 years. The water insoluble (WIS) components contribute 71% to the oxidative toxicity of road dust and show a rapid toxicity generation process, while the oxidative toxicity generation rate of water-soluble dust is more stable. Based on the positive matrix factorization (PMF) model, the contribution of EPFRs-dominated factors to Total-OT and WIS-OT is 17.3% and 33.3%, respectively. The PMF model results indicated that different types of EPFRs contributed differently to the oxidative toxicity of road dust and Carbon-centered EPFRs are more likely to participate in reactive oxygen species generation. Our results highlight that the EPFRs are an important contributor to the oxidative toxicity of atmospheric particulate matter, and their oxidative toxicity is dependent on the types of free radicals. It also provides an important insight into the influence of other potentially toxic substances on the oxidative toxicity of atmospheric PM.

环境持久性自由基（EPFRs）是大气中新的环境健康风险物质，其氧化毒性（OT）尚未得到有力证实。本研究调查了中国西北某大城市道路灰尘中 EPFRs 的逃逸特性及其潜在的氧化毒性。结果表明，道路扬尘中含有以碳为中心的EPFRs，平均质量浓度为（6.6±5.0）×10 ¹⁷旋转/克。道路灰尘中的 EPFR 是可降解的，半衰期为 4.5 年。水不溶性（WIS）成分对道路粉尘氧化毒性的贡献率为71%，并呈现出快速的毒性生成过程，而水溶性粉尘的氧化毒性生成速率更为稳定。基于正矩阵分解（PMF）模型，EPFRs主导因素对Total-OT和WIS-OT的贡献分别为17.3%和33.3%。PMF模型结果表明，不同类型的EPFRs对道路粉尘氧化毒性的贡献不同，以碳为中心的EPFRs更有可能参与活性氧的生成。我们的研究结果强调，EPFR 是大气颗粒物氧化毒性的重要贡献者，它们的氧化毒性取决于自由基的类型。它还为其他潜在有毒物质对大气 PM 氧化毒性的影响提供了重要的见解。