Relative importance of school bus-related microenvironments to children's pollutant exposure
Relative importance of school bus-related microenvironments to children's pollutant exposure
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DOI：
10.1080/10473289.2005.10464739
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发表时间：
2005-10-01
影响因子：
2.7
通讯作者：
Fruin, SA
中科院分区：
文献类型：
--
作者：
Behrentz, E;Sabin, LD;Fruin, SA
在洛杉矶联合学区公交路线上、沿途公交站点、选定学校门前的公交上下车区以及附近城市“背景”站点，测量了长时间通勤期间校车内黑碳、颗粒结合多环芳烃、二氧化氮和细颗粒物的实时浓度，以及综合和实时细颗粒物（PM,.,）质量浓度。在所有污染物中，公交通勤期间的平均浓度高于任何其他微环境。根据污染物的不同，公交通勤的平均暴露量（在特定微环境中花费的平均浓度乘以时间）是上下车微环境的50至200倍，是公交车站的20至40倍。虽然所分析的校车通勤只占孩子一天工作时间的10%，但平均而言，校车通勤占孩子一天24小时黑碳暴露总量的三分之一。对于与车辆废气密切相关的物种，当车窗打开时，车内暴露通常受周围交通的影响，而当车窗关闭时，受公交车自身废气的影响。一般来说，低排放的公交车只有在跟在柴油车后面行驶时才会出现高浓度，而高排放的公交车在跟在其他柴油车后面以及在没有其他柴油车的情况下空转时都会出现高浓度。为了减少校车通勤暴露，我们建议尽量减少通勤时间，避免与其他校车一起使用大篷车，在最长的公交路线上使用最清洁的公交车，保持传统的柴油公交车以消除可见排放，并尽快过渡到更清洁的燃料和先进的微粒控制技术。
Real-time concentrations of black carbon, particle-bound polycyclic aromatic hydrocarbons, nitrogen dioxide, and fine particulate counts, as well as integrated and real-time fine particulate matter (PM,.,) mass concentrations were measured inside school buses during long commutes on Los Angeles Unified School District bus routes, at bus stops along the routes, at the bus loading/unloading zone in front of the selected school, and at nearby urban "background" sites. Across all of the pollutants, mean concentrations during bus commutes were higher than in any other microenvironment. Mean exposures (mean concentration times time spent in a particular microenvironment) in bus commutes were between 50 and 200 times greater than those for the loading/unloading microenvironment, and 20-40 times higher than those for the bus stops, depending on the pollutant. Although the analyzed school bus commutes represented only 10% of a child's day, on average they contributed one-third of a child's 24-hr overall black carbon exposure during a school day. For species closely related to vehicle exhaust, the within-cabin exposures were generally dominated by the effect of surrounding traffic when windows were open and by the bus's own exhaust when windows were closed. Low-emitting buses generally exhibited high concentrations only when traveling behind a diesel vehicle, whereas high-emitting buses exhibited high concentrations both when following other diesel vehicles and when idling without another diesel vehicle in front of the bus. To reduce school bus commute exposures, we recommend minimizing commute times, avoiding caravanning with other school buses, using the cleanest buses for the longest bus routes,, maintaining conventional diesel buses to eliminate visible emissions, and transitioning to cleaner fuels and advanced particulate control technologies as soon as possible.