Particulate matter (PM) concentrations in underground and ground-level rail systems of the Los Angeles Metro
Particulate matter (PM) concentrations in underground and ground-level rail systems of the Los Angeles Metro
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DOI：
10.1016/j.atmosenv.2010.12.049
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发表时间：
2011-03-01
影响因子：
5
通讯作者：
Sioutas, Constantinos
中科院分区：
文献类型：
--
作者：
Kam, Winnie;Cheung, Kalam;Sioutas, Constantinos
在全球许多地下交通系统中发现颗粒物 (PM) 浓度升高，这对通勤者接触颗粒物及其相关健康影响产生重大影响。 2010 年 5 月至 8 月进行了一次广泛的采样活动，测量洛杉矶地铁系统两条线路——地下地铁线（地铁红线）和地面轻轨线（地铁金线）的 PM 浓度。该活动的目标是：1) 确定两条线路通勤者的个人 PM 暴露量，2) 测量和比较车站站台和列车内部的 PM 浓度。考虑到乘客通常 75% 的时间在火车内，25% 的时间在车站等待，地铁乘客平均接触到的 PM10 和 PM2.5 浓度分别是轻轨乘客的 1.9 和 1.8 倍。地铁线路车站站台和车内PM10平均浓度分别为78.0μg·m(-3)和31.5μg·m(-3)；轻轨线对应的PM10浓度分别为38.2μg·m(-3)和16.2μg·m(-3)。回归分析表明，轻轨线的个人暴露浓度与环境PM水平密切相关（R-2 = 0.61），而地铁线的PM浓度受环境条件影响较小（R-2 = 0.38），背景水平相对稳定，约为21 μg m(-3)。我们的研究结果表明，当地排放（即车辆交通、道路灰尘）是轻轨线路空气中颗粒物的主要来源。另一方面，地铁线路有一个额外的颗粒物来源，很可能是由列车的日常运行产生的。列车和车站微环境之间 PM10 的强相关性表明，车站空气中的 PM 是两条线路列车内 PM10 的主要来源（地铁和轻轨线路的 R-2 分别为 0.91 和 0.81）。此外，地铁线路（R-2 = 0.89）和轻轨线路（R-2 = 0.52-0.92）的PM2.5和粗颗粒物（PM10-2.5）也具有很强的相关性，表明PM2.5和粗颗粒物有共同的来源。最后，与全球地铁系统相比，洛杉矶。地铁系统相对“干净”。由于该系统相对较新（自 1993 年开始运营），其通风系统和制动技术可能比旧地铁系统更高效、更先进。 (C) 2010 Elsevier Ltd. 保留所有权利。
Elevated concentrations of particulate matter (PM) have been found in a number of worldwide underground transit systems, with major implications regarding exposure of commuters to PM and its associated health effects. An extensive sampling campaign was conducted in May-August 2010 to measure PM concentrations in two lines of the Los Angeles Metro system - an underground subway line (Metro red line) and a ground-level light-rail line (Metro gold line). The campaign goals were to: 1) determine personal PM exposure of commuters of both lines, and 2) measure and compare PM concentrations at station platforms and inside the train. Considering that a commuter typically spent 75% of time inside the train and 25% of time waiting at a station, subway commuters were exposed on average to PM10 and PM2.5 concentrations that were 1.9 and 1.8 times greater than the light-rail commuters. The average PM10 concentrations for the subway line at station platforms and inside the train were 78.0 mu g m(-3) and 31.5 mu g m(-3), respectively; for the light-rail line, corresponding PM10 concentrations were 38.2 mu g m(-3) and 16.2 mu g m(-3). Regression analysis demonstrated that personal exposure concentrations for the light-rail line are strongly associated with ambient PM levels (R-2 = 0.61), while PM concentrations for the subway line are less influenced by ambient conditions (R-2 = 0.38) and have a relatively stable background level of about 21 mu g m(-3). Our findings suggest that local emissions (i.e., vehicular traffic, road dust) are the main source of airborne PM for the light-rail line. The subway line, on the other hand, has an additional source of PM, most likely generated from the daily operation of trains. Strong inter-correlation of PM10 between the train and station microenvironments shows that airborne PM at stations are the main source of PM inside the trains for both lines (R-2 = 0.91 and 0.81 for subway and light-rail line, respectively). In addition, PM2.5 and coarse PM (PM10-2.5) are also strongly correlated for the subway line (R-2 = 0.89) and the light-rail line (R-2 = 0.52-0.92), suggesting that PM2.5 and coarse PM originate from a common source. Finally, in comparison to worldwide subway systems, the LA. Metro system is relatively 'clean'. Since the system is comparatively new (in operation since 1993), its ventilation system and braking technology are probably more efficient and more advanced than older subway systems. (C) 2010 Elsevier Ltd. All rights reserved.