San Diego State University Graduate School of Public Health, 5500 Campanile Drive, San Diego, CA 92182-4162, USA.
Millersville University, Department of Applied Engineering, Safety & Technology Occupational Safety & Environmental Health Program, 40 East Frederick Street, Millersville, PA 17551, USA.
Sci Total Environ. 2018 May 1;622-623:236-243. doi: 10.1016/j.scitotenv.2017.11.319. Epub 2017 Dec 13.
At US-Mexico border Ports of Entry, vehicles idle for long times waiting to cross northbound into the US. Long wait times at the border have mainly been studied as an economic issue, however, exposures to emissions from idling vehicles can also present an exposure risk. Here we present the first data on in-vehicle exposures to driver and passengers crossing the US-Mexico border at the San Ysidro, California Port of Entry (SYPOE). Participants were recruited who regularly commuted across the border in either direction and told to drive a scripted route between two border universities, one in the US and one in Mexico. Instruments were placed in participants' cars prior to commute to monitor-1-minute average levels of the traffic pollutants ultrafine particles (UFP), black carbon (BC) and carbon monoxide (CO) in the breathing zone of drivers and passengers. Location was determined by a GPS monitor. Results reported here are for 68 northbound participant trips. The highest median levels of in-vehicle UFP were recorded during the wait to cross at the SYPOE (median 29,692particles/cm) significantly higher than the portion of the commute in the US (median 20,508particles/cm) though not that portion in Mexico (median 22, 191particles/cm). In-vehicle BC levels at the border were significantly lower than in other parts of the commute. Our results indicate that waiting in line at the SYPOE contributes a median 62.5% (range 15.5%-86.0%) of a cross-border commuter's exposure to UFP and a median 44.5% (range (10.6-79.7%) of exposure to BC inside the vehicle while traveling in the northbound direction. Reducing border wait time can significantly reduce in-vehicle exposures to toxic air pollutants such as UFP and BC, and these preventable exposures can be considered an environmental justice issue.
在美国-墨西哥边境入境口岸，车辆长时间等待向北进入美国。边境地区的长时间等待主要被视为一个经济问题，然而，车辆怠速时排放的污染物也会带来暴露风险。在这里，我们首次提供了在加利福尼亚州圣地亚哥入境港（SYPOE）穿越美国-墨西哥边境的司机和乘客车内暴露的数据。研究招募了经常往返于边境的参与者，并要求他们按照脚本路线在两国的两所边境大学之间行驶，一所位于美国，一所位于墨西哥。在通勤前，将仪器放置在参与者的车内，以监测司机和乘客呼吸区的 1 分钟平均水平的交通污染物超细颗粒（UFP）、黑碳（BC）和一氧化碳（CO）。位置由 GPS 监测器确定。这里报告的结果是 68 次向北的出行。在 SYPOE 等待过境时，车内 UFP 的中位数水平最高（中位数 29692 个/立方厘米），明显高于在美国境内通勤的部分（中位数 20508 个/立方厘米），但低于在墨西哥境内通勤的部分（中位数 22191 个/立方厘米）。边境地区车内 BC 水平明显低于通勤的其他部分。我们的研究结果表明，在 SYPOE 排队等候导致过境通勤者车内 UFP 暴露的中位数增加了 62.5%（范围 15.5%-86.0%），而在向北行驶时，车内 BC 暴露的中位数增加了 44.5%（范围 10.6%-79.7%）。减少边境等待时间可以显著降低车内接触有毒空气污染物（如 UFP 和 BC）的风险，这些可预防的暴露可以被视为一个环境正义问题。
