Chaney Robert A, Sloan Chantel D, Cooper Victoria C, Robinson Daniel R, Hendrickson Nathan R, McCord Tyler A, Johnston James D
Brigham Young University, Department of Health Science, Provo, Utah, United States of America.
PLoS One. 2017 Nov 9;12(11):e0188053. doi: 10.1371/journal.pone.0188053. eCollection 2017.
Traffic-related air pollution in urban areas contributes significantly to commuters' daily PM2.5 exposures, but varies widely depending on mode of commuting. To date, studies show conflicting results for PM2.5 exposures based on mode of commuting, and few studies compare multiple modes of transportation simultaneously along a common route, making inter-modal comparisons difficult. In this study, we examined breathing zone PM2.5 exposures for six different modes of commuting (bicycle, walking, driving with windows open and closed, bus, and light-rail train) simultaneously on a single 2.7 km (1.68 mile) arterial urban route in Salt Lake City, Utah (USA) during peak "rush hour" times. Using previously published minute ventilation rates, we estimated the inhaled dose and exposure rate for each mode of commuting. Mean PM2.5 concentrations ranged from 5.20 μg/m3 for driving with windows closed to 15.21 μg/m3 for driving with windows open. The estimated inhaled doses over the 2.7 km route were 6.83 μg for walking, 2.78 μg for cycling, 1.28 μg for light-rail train, 1.24 μg for driving with windows open, 1.23 μg for bus, and 0.32 μg for driving with windows closed. Similarly, the exposure rates were highest for cycling (18.0 μg/hr) and walking (16.8 μg/hr), and lowest for driving with windows closed (3.7 μg/hr). Our findings support previous studies showing that active commuters receive a greater PM2.5 dose and have higher rates of exposure than commuters using automobiles or public transportation. Our findings also support previous studies showing that driving with windows closed is protective against traffic-related PM2.5 exposure.
城市地区与交通相关的空气污染对通勤者日常的细颗粒物（PM2.5）暴露有显著影响，但因通勤方式而异。迄今为止，关于基于通勤方式的PM2.5暴露研究结果相互矛盾，很少有研究在同一路线上同时比较多种交通方式，这使得不同交通方式间的比较变得困难。在本研究中，我们在美国犹他州盐湖城一条2.7公里（1.68英里）的城市主干道上，于高峰“通勤时段”同时检测了六种不同通勤方式（自行车、步行、开着车窗和关着车窗驾车、公交车、轻轨列车）时呼吸区域的PM2.5暴露情况。利用先前发表的每分钟通气率，我们估算了每种通勤方式的吸入剂量和暴露率。平均PM2.5浓度范围从关窗驾车时的5.20微克/立方米到开窗驾车时的15.21微克/立方米。在2.7公里的路程中，估算的吸入剂量分别为：步行6.83微克、骑自行车2.78微克、轻轨列车1.28微克、开窗驾车1.24微克、乘坐公交车1.23微克、关窗驾车0.32微克。同样，暴露率最高的是骑自行车（18.0微克/小时）和步行（16.8微克/小时），最低的是关窗驾车（3.7微克/小时）。我们的研究结果支持了先前的研究，即积极通勤者比使用汽车或公共交通的通勤者吸入更多的PM2.5剂量且暴露率更高。我们的研究结果还支持了先前的研究，即关窗驾车可减少与交通相关的PM2.5暴露。
