Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure.
Ultrafine particle size distributions near freeways: Effects of differing wind directions on exposure.
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DOI：
10.1016/j.atmosenv.2012.09.045
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发表时间：
2012-12
影响因子：
5
通讯作者：
Fruin, Scott A.
中科院分区：
文献类型：
--
作者：
Kozawa, Kathleen H.;Winer, Arthur M.;Fruin, Scott A.
高环境超细颗粒（UFP）浓度可能在与繁忙道路附近生活相关的不良健康影响中发挥重要作用。然而，UFP大小分布随着车辆排放的稀释和老化而迅速变化。这些颗粒大小的变化会影响UFP肺沉积速率和剂量，因为呼吸系统中的沉积与颗粒大小有很大关系。迄今为止，很少有研究实时测量和描述近路UFP尺寸分布的变化，因此缺少由于风速、方向或粒子动力学的短期波动而导致的尺寸分布的瞬态变化。在这项研究中，我们使用5秒时间分辨率的移动平台测量了风向对高速公路附近UFP大小分布和梯度的重要影响。与更常见的垂直（下风）条件相比，平行风条件似乎促进了颗粒浓度大约一半的更广泛和更大的分布。在更平行的风条件下，颗粒的大小随顺风距离的变化也较小，计算得出肺沉积颗粒数的比例比顺风条件下低15%，合计减少约60%。此外，对几个变量的多变量分析发现，气象学，特别是风向和温度，对于预测高速公路150米范围内UFP浓度很重要（R2 = 0.46, p = 0.014）。
High ambient ultrafine particle (UFP) concentrations may play an important role in the adverse health effects associated with living near busy roadways. However, UFP size distributions change rapidly as vehicle emissions dilute and age. These size changes can influence UFP lung deposition rates and dose because deposition in the respiratory system is a strong function of particle size. Few studies to date have measured and characterized changes in near-road UFP size distributions in real-time, thus missing transient variations in size distribution due to short-term fluctuations in wind speed, direction, or particle dynamics. In this study we measured important wind direction effects on near-freeway UFP size distributions and gradients using a mobile platform with 5-s time resolution. Compared to more commonly measured perpendicular (downwind) conditions, parallel wind conditions appeared to promote formation of broader and larger size distributions of roughly one-half the particle concentration. Particles during more parallel wind conditions also changed less in size with downwind distance and the fraction of lung-deposited particle number was calculated to be 15% lower than for downwind conditions, giving a combined decrease of about 60%. In addition, a multivariate analysis of several variables found meteorology, particularly wind direction and temperature, to be important in predicting UFP concentrations within 150 m of a freeway (R2 = 0.46, p = 0.014).
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影响因子：
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通讯作者：
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