Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control (IJRC), Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
Key Joint Laboratory of Environmental Simulation and Pollution Control, International Joint Laboratory for Regional Pollution Control (IJRC), Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; School of Ecology and Environment, Beijing Technology and Business University, Beijing 100048, China.
Sci Total Environ. 2023 Oct 10;894:164528. doi: 10.1016/j.scitotenv.2023.164528. Epub 2023 May 31.
Fine particles (PM) are implicated as an important risk to cardiovascular health. N95 respirators had been widely used to provide protection by filtering particles. Yet the practical effects of wearing respirators have not been fully understood. This study aimed to evaluate the cardiovascular effects of respirator wearing against PM and underpin the understanding of the mechanisms of cardiovascular responses triggered by PM. We conducted a randomized, double-blind crossover trial among 52 healthy adults in Beijing, China. Participants were exposed to outdoor PM for 2 h in alterations wearing true respirators (with membranes) or sham ones (without membranes). We measured ambient PM and tested the filtration efficiency of the respirators. We compared the heart rate variability (HRV), blood pressure and arterial stiffness indicators between the true respirator group and the sham respirator group. Concentrations of ambient PM during the 2-h exposure ranged from 4.9 to 255.0 μg/m. The filtration efficiency of true respirators was 90.1 % and that of sham ones was 18.7 %. Between-group differences varied by pollution levels. On less polluted days (PM< 75 μg/m), participants wearing true respirators showed lower levels of HRV and higher levels of heart rate compared with those wearing sham respirators. These between-group differences were inconspicuous on heavily polluted days (PM≥ 75 μg/m). We found that a 10 μg/m increase in PM was associated with a 2.2 % to 6.4 % decrease in HRV, prominent at 1 h after the start of exposure. N95 respirators have good performance in reducing PM exposure. Short-term exposure to PM can induce very acute responses in autonomic nervous function. However, the overall effects of wearing respirators might be not always favorable to human health in terms of their inherent adverse effects, which seem dependent on the levels of air pollution. Precise individual protection recommendations warrant to be developed.
细颗粒物 (PM) 被认为是对心血管健康的重要危险因素。N95 呼吸器已被广泛用于通过过滤颗粒物来提供保护。然而，佩戴呼吸器的实际效果尚未得到充分理解。本研究旨在评估佩戴呼吸器对 PM 的心血管影响，并为理解 PM 引发的心血管反应机制提供依据。我们在中国北京的 52 名健康成年人中进行了一项随机、双盲交叉试验。参与者在户外 PM 暴露 2 小时，佩戴真实呼吸器（有膜）或假呼吸器（无膜）。我们测量了环境 PM 并测试了呼吸器的过滤效率。我们比较了真实呼吸器组和假呼吸器组之间的心率变异性 (HRV)、血压和动脉僵硬指标。2 小时暴露期间环境 PM 浓度范围为 4.9 至 255.0μg/m。真实呼吸器的过滤效率为 90.1%，假呼吸器的过滤效率为 18.7%。组间差异随污染水平而变化。在污染较轻的日子（PM<75μg/m），与佩戴假呼吸器的参与者相比，佩戴真实呼吸器的参与者 HRV 水平较低，心率较高。在污染较重的日子（PM≥75μg/m），这些组间差异不明显。我们发现，PM 增加 10μg/m 与 HRV 降低 2.2%至 6.4%相关，在暴露开始后 1 小时明显。N95 呼吸器在减少 PM 暴露方面表现良好。短期暴露于 PM 可导致自主神经系统功能出现非常急性的反应。然而，就其固有副作用而言，佩戴呼吸器的总体效果对人类健康可能并不总是有利，这似乎取决于空气污染水平。需要制定精确的个体保护建议。
