BACKGROUND PM2.5 pollution waves (PPWs) are severe air pollution events with extremely high-level concentration of ambient PM2.5. PPWs, such as haze days, were suggested to be associated with increased cardiopulmonary mortality and morbidity. However, the biological mechanism response to ambient PM2.5 during PPWs is still unclear. METHODS A randomized crossover trial was conducted on 29 healthy young adults. Repeated health measurements were performed before, during and after two typical PPWs under filtered and sham indoor air purification, with a washout interval of at least 2 weeks. Health parameters including blood pressure (BP), pulmonary function, fractional exhaled nitric oxide (FeNO) and circulating biomarkers which reflect platelet activation, blood coagulation and systematic oxidative stress were measured. RESULTS Ambient PM2.5 levels elevated apparently during PPWs. Under sham purification, significant increase in FeNO and soluble P-selectin (sP-selectin) and decreases in pulmonary function were observed from pre-PPWs period to during-PPWs period. The changes in health biomarkers as mentioned above became attenuated and insignificant under filtered condition. For instance, sP-selectin increased by 12.0% (95% CI: 3.8%, 20.8%) during-PPWs periods compared with pre-PPWs periods under sham purification, while non-significant change was observed under filtered condition. Significant associations between time-weighted personal PM2.5 exposure and increased levels of health biomarkers including FeNO, sP-selectin, oxidized low-density lipoprotein (ox-LDL) and 8-isoprostane (8-isoPGF2α) were found. CONCLUSION PPWs could affect cardiopulmonary health through systematic oxidative stress, platelet activation and respiratory inflammation in healthy adults, and short-term indoor air purification could alleviate the adverse cardiopulmonary effects.

中文翻译：

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环境 PM2.5 污染波期间对细颗粒的心肺反应：一项针对年轻健康成人的随机交叉试验的结果。

背景 PM2.5 污染波 (PPW) 是环境 PM2.5 浓度极高的严重空气污染事件。PPW，例如雾霾天，被认为与心肺死亡率和发病率增加有关。然而，PPWs 期间对环境 PM2.5 的生物机制响应仍不清楚。方法 对 29 名健康的年轻人进行了一项随机交叉试验。在过滤和假室内空气净化下的两个典型 PPW 之前、期间和之后进行了重复的健康测量，清洗间隔至少为 2 周。测量了包括血压 (BP)、肺功能、呼出气一氧化氮 (FeNO) 和反映血小板活化、血液凝固和系统性氧化应激的循环生物标志物在内的健康参数。结果 环境 PM2. 5 级在 PPW 期间明显升高。在假纯化下，从 PPW 前到 PPW 期间，FeNO 和可溶性 P-选择素 (sP-选择素) 显着增加，肺功能下降。上述健康生物标志物的变化在过滤条件下变得减弱且不显着。例如，与假纯化下的预 PPW 时期相比，在 PPW 期间，sP-选择素增加了 12.0%（95% CI：3.8%，20.8%），而在过滤条件下观察到不显着的变化。发现时间加权个人 PM2.5 暴露与包括 FeNO、sP-选择素、氧化低密度脂蛋白 (ox-LDL) 和 8-异前列腺素 (8-isoPGF2α) 在内的健康生物标志物水平升高之间存在显着关联。