Ji Wenjing, Liu Chenghao, Liu Zhenzhe, Wang Chunwang, Li Xiaofeng
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.
Environ Pollut. 2021 Apr 15;275:116627. doi: 10.1016/j.envpol.2021.116627. Epub 2021 Feb 2.
Concentrations of airborne metal-rich particles are typically higher on subway platforms and in subway tunnels than in ambient air. The subway concourse is an area of direct air exchange with both platforms and the outside environment, but few researchers have measured the concentrations and composition of fine particles on subway concourses. We characterized the concentrations and composition of fine particles on six subway concourses in Nanjing, China in both summer and winter. We used a respiration rate-adjusted microenvironment exposure model to estimate the contribution of a 6-h work period to daily mean exposure to fine particulate matter of subway workers and compared the estimate with those for general indoor and outdoor workers. We found that particle concentrations were typically higher on the station concourses than in ambient air. The most abundant elements composing the particles were Fe, S, Ca, Si, and K in both subway concourses and reference ambient air, but their contents varied greatly between indoor and outdoor air. The indoor/outdoor ratios of Fe, Cu, and Mn were highest, and subway workers were disproportionately exposed to these three metals. The mean daily exposure dose to Fe was 44.8 μg for subway workers, approximately five times the exposure dose of indoor and outdoor workers. Daily exposure doses of Cu, Mn, V, Sr, As, Co, Sn, and Cr were also higher for subway workers. The quality of indoor air at subway stations is therefore of occupational health concern and strategies should be formulated to reduce worker exposure.
地铁站台和地铁隧道中富含金属的空气传播颗粒浓度通常高于室外空气。地铁大厅是与站台和外部环境直接进行空气交换的区域，但很少有研究人员测量过地铁大厅中细颗粒物的浓度和成分。我们对中国南京六个地铁大厅在夏季和冬季的细颗粒物浓度和成分进行了表征。我们使用了一种经呼吸速率调整的微环境暴露模型，来估算地铁工作人员6小时工作日对细颗粒物日均暴露量的贡献，并将该估算值与一般室内和室外工作人员的估算值进行比较。我们发现，车站大厅中的颗粒物浓度通常高于室外空气。构成这些颗粒物的最丰富元素在地铁大厅和参考室外空气中均为铁、硫、钙、硅和钾，但其含量在室内和室外空气中差异很大。铁、铜和锰的室内/室外比值最高，地铁工作人员不成比例地暴露于这三种金属中。地铁工作人员铁的日均暴露剂量为44.8μg，约为室内和室外工作人员暴露剂量的五倍。地铁工作人员铜、锰、钒、锶、砷、钴、锡和铬的日均暴露剂量也更高。因此，地铁站室内空气质量关乎职业健康，应制定相应策略以减少工作人员的暴露。
