Karim Anjum Shahina, Malone Maeve, Bruno Alex, Eggler Aimee L, Posner Michael A, Shakya Kabindra M
Department of Geography and the Environment, Villanova University, Villanova, PA, USA.
Department of Chemistry, Villanova University, Villanova, PA, USA.
J Expo Sci Environ Epidemiol. 2025 Apr;35(2):196-204. doi: 10.1038/s41370-024-00711-9. Epub 2024 Aug 14.
Subways are popular and efficient modes of transportation in cities. However, people are exposed to high levels of particulate matter (PM) in subways. Subway air quality in the United States has been investigated in a few cities, but data is lacking on simultaneous measurement of several pollutants, especially ultrafine particles (UFP) and black carbon (BC), in combination with different size fractions of PM.
The goals of this study are to assess air quality in a belowground subway and compare it with outdoor ambient levels, to examine temporal variability of PM in the subway, and to analyze the correlation between PM and BC.
Particulate matter of varying sizes (PM, PM, PM), UFP, and BC were measured using DustTrak, nanoparticle detector, and micro aethalometer, respectively. Measurements were made at the belowground subway platform and the aboveground street level at 15th Street subway station in Philadelphia during summer 2022.
Belowground mean PM, PM, and PM were 112.2 ± 61.3 µg/m, 120 ± 65.5 µg/m, and 182.1 ± 132 µg/m, respectively, which were 5.4, 5.7, and 7.6 times higher than the respective aboveground street levels. The UFP lung deposited surface area (LDSA) (59.4 ± 36.2 µm/cm) and BC (9.5 ± 5.4 μg/m) belowground were 1.7 times and 10.7 times higher than the aboveground. The pollutant concentration varied from day-to-day on both the locations. A higher positive correlation was found between the belowground BC and PM (r = 0.51, p < 0.05) compared to the aboveground (r = 0.16, p < 0.05).
This study showed high levels of particulate matter exposure at a belowground subway station in Philadelphia. Particulate matter levels were about 5 to 8 times higher at belowground subway station than the corresponding aboveground street level. Higher levels were also observed for UFP lung deposited surface area (LDSA), while black carbon levels showed the highest concentration at the belowground level by a factor of ten compared to the aboveground level. The study shows the need for air quality management at belowground subways to reduce particulate matter exposure for the commuters.
地铁是城市中受欢迎且高效的交通方式。然而，人们在地铁中会接触到高浓度的颗粒物（PM）。美国已在一些城市对地铁空气质量进行了调查，但缺乏关于几种污染物同时测量的数据，特别是超细颗粒物（UFP）和黑碳（BC），以及不同粒径分数的PM的相关数据。
本研究的目标是评估地下地铁站的空气质量，并将其与室外环境水平进行比较，研究地铁中PM的时间变化，并分析PM与BC之间的相关性。
分别使用粉尘仪、纳米颗粒探测器和微型黑碳仪测量不同粒径的颗粒物（PM、PM、PM）、UFP和BC。2022年夏季，在费城第15街地铁站的地下站台和地面街道进行了测量。
地下PM、PM和PM的平均浓度分别为112.2±61.3μg/m、120±65.5μg/m和182.1±132μg/m，分别是相应地面街道水平的5.4倍、5.7倍和7.6倍。地下UFP的肺部沉积表面积（LDSA）（59.4±36.2μm/cm）和BC（9.5±5.4μg/m）分别是地面的1.7倍和10.7倍。两个地点的污染物浓度每天都有所变化。与地面相比，地下BC与PM之间的正相关性更高（r = 0.51，p < 0.05）（地面r = 0.16，p < 0.05）。
本研究表明，费城一个地下地铁站的颗粒物暴露水平很高。地下地铁站的颗粒物水平比相应的地面街道水平高约5至8倍。UFP肺部沉积表面积（LDSA）也观察到较高水平，而黑碳水平在地下显示出比地面高十倍的最高浓度。该研究表明需要对地下地铁的空气质量进行管理，以减少通勤者的颗粒物暴露。
