Zhu Yifang, Eiguren-Fernandez Arantzazu, Hinds William C, Miguel Antonio H
Department of Environmental Engineering, Texas A&M University-Kingsville, 700 University Boulevard, MSC 213, Kingsville, Texas 78363, USA.
Environ Sci Technol. 2007 Apr 1;41(7):2138-45. doi: 10.1021/es0618797.
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 (approximately 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 approximately 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.
在世界各地，人们在各种情况下都会接触到有毒的超细颗粒（UFP，直径（dp）小于100纳米）和纳米颗粒（NP，dp < 50纳米）。迄今为止，关于人们在主要道路和高速公路上行驶时接触新排放的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车内和车外颗粒物数量浓度及粒径分布的测量结果。在不同的车辆通风设置下测量了颗粒物数量浓度和粒径分布。当循环风扇设置为开启状态且有大量外部进气时，车外颗粒物数量的变化会在大约30 - 60秒后引起车内相应的变化，这表明最大空气交换率约为120 - 60 h⁻¹。当风扇和再循环都开启时，可获得最大的车内防护效果（约85%）。观察到车内和车外7.9 - 217纳米范围内的粒径分布大多为双峰分布，主峰出现在10 - 30纳米，次峰出现在50 - 70纳米。车辆出厂时安装的颗粒过滤器对7 - 40纳米粒径范围内的颗粒提供约50%的车内防护，对40至约200纳米粒径范围内的颗粒提供20 - 30%的防护。对于每天一小时的通勤暴露，车内微环境对人们日常交通UFP暴露的贡献约为10 - 50%。
