In-cabin commuter exposure to ultrafine particles on Los Angeles freeways
In-cabin commuter exposure to ultrafine particles on Los Angeles freeways
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DOI：
10.1021/es0618797
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发表时间：
2007-04-01
影响因子：
11.4
通讯作者：
Miguel, Antonio H.
中科院分区：
文献类型：
--
作者：
Zhu, Yifang;Eiguren-Fernandez, Arantzazu;Miguel, Antonio H.
世界各地的人们在各种情况下接触到有毒的超细颗粒(UFP，直径小于100 nm)和纳米颗粒(NP，DP<；50 nm)。到目前为止，关于人类在主要道路和高速公路上行驶时接触到新排放的UFP和NP的信息非常有限。我们报告了在洛杉矶高速公路上驾驶三辆车时，机舱内和室外对颗粒物数量、浓度和尺寸分布的测量。在不同的车辆通风条件下，测量了颗粒物的数量浓度和粒度分布。当循环风机设置为开时，随着外部进风量的大幅增加，外部颗粒物计数的变化在大约30-60h S后引起舱内相应的变化，表明最大换气率约为120h-60h(-1)。当风扇和再循环都开启时，可获得最大的舱内保护(接近85%)。在7.9-217 nm范围内，室内和室外的粒径分布基本呈双峰分布，第一峰出现在10-30 nm，第二峰出现在50-70 nm。车辆制造安装的颗粒过滤器为7-40 nm尺寸范围内的颗粒提供了约50%的舱内保护，为40-200 nm尺寸范围内的颗粒提供了20-30%的保护。在每天一小时的通勤暴露中，车载微环境约占人们每天从交通中接触到的UFP的10%-50%。
Worldwide people are exposed to toxic ultrafine particles (UFP, with diameters (dp) less than 100 nm) and nanoparticles (NP, dp < 50 nm) under a variety of circumstances. To date, very limited information is available on human exposure to freshly emitted UFP and NP while traveling on major roads and freeways. We report in-cabin and outdoor measurements of particle number concentration and size distributions while driving three vehicles on Los Angeles freeways. Particle number concentrations and size distributions were measured under different vehicle ventilation settings. When the circulation fan was set to on, with substantial external air intake, outside changes in particle counts caused corresponding in-cabin changes approximately 30-60 s later, indicating an maximal air exchange rate of about 120-60 h(-1). Maximum in-cabin protection (similar to 85%) was obtained when both fan and recirculation were on. In-cabin and outdoor particle size distributions in the 7.9-217 nm range were observed to be mostly bimodal, with the primary peak occurring at 10-30 nm and the secondary at 50-70 nm. The vehicle's manufacture-installed particle filter offered an in-cabin protection of about 50% for particles in the 7-40 nm size range and 20-30% for particles in the 40 to similar to 200 nm size range. For an hour daily commute exposure, the in-vehicle microenvironment contributes approximately 10-50% of people's daily exposure to UFP from traffic.