Ground-fixed and on-board measurements of nanoparticles in the wake of a moving vehicle
Ground-fixed and on-board measurements of nanoparticles in the wake of a moving vehicle
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移动车辆尾随地面固定和车载测量纳米粒子
DOI：
10.1016/j.atmosenv.2011.06.079
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发表时间：
2011
影响因子：
5
通讯作者：
Carpentieri M
中科院分区：
文献类型：
--
作者：
Carpentieri M
一个集成的实验方法已被应用到测量的颗粒的数量和尺寸分布在5-560 nm的尺寸范围内的柴油车运行在不同的速度后。使用采样频率高达10 Hz的快速响应差分迁移率光谱仪（Cameroon DMS 50），在地面固定（地面以上0.10和0.25 m）和车载（移动汽车后面的12个不同采样位置）测量配置下进行测量。分析了两个实验活动的结果，以了解移动车辆后纳米颗粒排放的动力学，分散和运输。结果的时间变化分为三个主要阶段（前演变，演变和后演变）后，从排气管排放的废气释放。演化阶段是颗粒数量和粒度分布发生变化的阶段。多达四个演变的子阶段进行了观察，每个显示不同的粒径分布的演变模式，这取决于特定的实验运行。与以前的研究一致，稀释被认为是整个演化阶段的主导过程。第一个演变子阶段是共同的所有的测量，并包括初始颗粒数浓度和分布的变化，由于快速（小于1秒）的成核，然后由一个快速增加的积累模式的颗粒数浓度。在这第一个子阶段之后，带有再循环颗粒的飞行器尾流的存在以及其他转化过程的可能影响导致复杂的相互作用。来自两个实验数据集的结果清楚地证实了两组单独的颗粒的存在：（i）新颗粒，其新鲜排放并直接来自排气管;以及（ii）相对老化的颗粒，其被夹带在车辆尾流的再循环涡流中并在那里停留较长时间。这两个群体具有不同的特点，并相互影响。这种相互作用往往被忽略了在过去的研究中，从移动车辆的纳米粒子的局部尺度分散。
An integrated experimental methodology has been applied to measure number and size distributions of particles in the 5–560 nm size range in the wake of a diesel car running at different speeds. Measurements were made at both ground-fixed (0.10 and 0.25 m above the ground level) and on-board (in 12 different sampling locations behind the moving car) measurement configurations using a fast response differential mobility spectrometer (Cambustion DMS50) with a sampling frequency up to 10 Hz. Results from both the experimental campaigns were analysed to understand the dynamics, dispersion and transport of nanoparticle emissions in the wake of a moving vehicle. Temporal changes in results were divided into three main stages (pre-evolution, evolution and post-evolution) after the release of exhaust emissions from the tailpipe. Evolution stage is of most interest where all the changes to particle number and size distribution occurred. Up to four evolution sub-stages were observed, each showing distinct evolution patterns of particle size distributions, depending on the particular experimental run. In agreement with previous studies, dilution was found to be the dominant process throughout all the evolution stages. The first evolution sub-stage was common to all the measurements, and consisted of an initial particle number concentrations and distributions change due to rapid (less than 1 s) nucleation followed by a rapid increase of accumulation mode particle number concentrations. After this first sub-stage the presence of vehicle wake with recirculating particles and the possible influence of other transformation processes lead to complex interactions. Results from the two experimental datasets clearly confirm the presence of two separate groups of particles: (i) new particles, which are freshly emitted and come directly from the tailpipe and (ii) relatively aged particles, which are entrained within the recirculation vortices of the vehicle wake and reside there for a longer time. The two groups have different characteristics and interact with each other. This interaction has often been overlooked in past studies about local scale dispersion of nanoparticle from moving vehicles.
剑桥街峡谷中街道与屋顶水平的细颗粒浓度
影响因子：
4.3
作者：
Prashant Kumar;P. Fennell;A. Hayhurst;R. Britter
通讯作者：
R. Britter
测定直径小于100 nm气溶胶颗粒干沉积速度的测量技术分析
影响因子：
4.5
作者：
G. Buzorius;Ü. Rannik;E. Nilsson;T. Vesala;M. Kulmala
通讯作者：
M. Kulmala