Department of Environmental Science and Engineering, Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary, Fudan University, Shanghai 200433, China.
School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266520, China.
Environ Sci Technol. 2024 Apr 16;58(15):6736-6743. doi: 10.1021/acs.est.4c00929. Epub 2024 Apr 2.
Acidity is an important property of particulate matter (PM) in the atmosphere, but its association with PM toxicity remains unclear. Here, this study quantitively reports the effect of the acidity level on PM toxicity via pH-control experiments and cellular analysis. Oxidative stress and cytotoxicity potencies of acidified PM samples at pH of 1-2 were up to 2.8-5.2 and 2.1-13.2 times higher than those at pH of 8-11, respectively. The toxic potencies of PM samples from real-world smoke plumes at the pH of 2.3 were 9.1-18.2 times greater than those at the pH of 5.6, demonstrating a trend similar to that of acidified PM samples. Furthermore, the impact of acidity on PM toxicity was manifested by promoting metal dissolution. The dramatic increase by 2-3 orders of magnitude in water-soluble metal content dominated the variation in PM toxicity. The significant correlation between sulfate, the pH value, water-soluble Fe, IC, and EC ( < 0.05) suggested that acidic sulfate could enhance toxic potencies by dissolving insoluble metals. The findings uncover the superficial association between sulfate and adverse health outcomes in epidemiological research and highlight the control of wet smoke plume emissions to mitigate the toxicity effects of acidity.
酸度是大气颗粒物（PM）的一个重要特性，但它与 PM 毒性的关系仍不清楚。在本研究中，通过 pH 控制实验和细胞分析，定量报告了酸度水平对 PM 毒性的影响。酸化 PM 样品在 pH 1-2 时的氧化应激和细胞毒性效价分别比 pH 8-11 时高 2.8-5.2 倍和 2.1-13.2 倍。实际烟尘中 PM 样品在 pH 2.3 时的毒性效价比 pH 5.6 时高 9.1-18.2 倍，表明与酸化 PM 样品的趋势相似。此外，酸度对 PM 毒性的影响表现为促进金属溶解。水溶性金属含量增加 2-3 个数量级，主导了 PM 毒性的变化。硫酸盐、pH 值、水溶性 Fe、IC 和 EC 之间存在显著相关性（<0.05），表明酸性硫酸盐可通过溶解不溶性金属来提高毒性效价。这些发现揭示了流行病学研究中硫酸盐与不良健康结果之间的表面关联，并强调了控制湿烟羽排放以减轻酸度毒性效应的重要性。
