School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Department of Building Science, School of Architecture, Tsinghua University, Beijing, 100084, China; Beijing Key Laboratory of Indoor Air Quality Evaluation and Control, Tsinghua University, Beijing, 100084, China.
Environ Res. 2021 Jun;197:111042. doi: 10.1016/j.envres.2021.111042. Epub 2021 Mar 19.
There is limited information on exposure to metallic constituents of fine particulate matter in subway stations. We characterized the concentrations and composition of airborne fine particulate pollution on six subway platforms in Nanjing, China in both summer and winter of 2019. A microenvironment exposure model was used to evaluate the concentrations of elements in fine particulate matter and the contribution of exposure duration (time spent in the subway station) to overall daily exposure of subway workers and commuters with and without the use of N95 respirators, surgical masks, and cotton masks. We found that airborne fine particulate pollution on station platforms was much higher than in an urban reference site of ambient air, and the same was true for metallic constituents of the particles, such as iron, copper, manganese, strontium, and vanadium. Subway workers were exposed to higher levels of these airborne metals than commuters. The average daily exposure concentration of fine particulate matter was 73.5 μg/m for subway workers and 61.8 μg/m for commuters, while the average daily exposure to iron was 15.5 μg/m for subway workers and 2.0 μg/m for commuters. Subway workers were exposed to iron, copper, manganese, and strontium/vanadium at levels approximately eight-fold, four-fold, three-fold, and two-fold greater than the exposure sustained by commuters, respectively. We calculated that wearing N95 respirators or surgical masks can reduce the exposure to these airborne metallic particles significantly for both subway workers and commuters. Overall, we estimate that personal exposure to airborne fine particulate matter on subway platforms can be reduced through the use of N95 respirators or properly fitting masks.
关于地铁站空气中细颗粒物中金属成分的暴露情况，信息有限。我们于 2019 年夏冬两季对中国南京 6 个地铁站台的空气细颗粒物污染浓度和成分进行了研究。采用微环境暴露模型来评估细颗粒物中元素的浓度，以及暴露时间（在地铁站停留的时间）对地铁工作人员和通勤者整体日常暴露的贡献，同时还考虑了是否使用 N95 口罩、医用口罩和棉质口罩。我们发现，站台上的空气细颗粒物污染水平远高于城市环境空气中的参考点，颗粒中的金属成分也是如此，例如铁、铜、锰、锶和钒。与通勤者相比，地铁工作人员接触这些空气中金属的水平更高。地铁工作人员细颗粒物的平均日暴露浓度为 73.5μg/m，通勤者为 61.8μg/m；地铁工作人员铁的平均日暴露浓度为 15.5μg/m，通勤者为 2.0μg/m。地铁工作人员接触铁、铜、锰和锶/钒的水平分别约为通勤者的 8 倍、4 倍、3 倍和 2 倍。我们计算得出，地铁工作人员和通勤者佩戴 N95 口罩或医用口罩可以显著减少这些空气中金属颗粒的暴露。总体而言，我们估计使用 N95 口罩或合适的口罩可以减少地铁站台空气中细颗粒物的个人暴露。
