ABSTRACT

This study used fine and coarse PM concentrator technology in a Mobile Particle Concentrator Platform (MPCP) designed and built to allow the collection of large amounts of ambient PM, enabling time-resolved speciation analysis, which would not be feasible using conventional methods. One hour of sampling yielded sufficient sample loading for trace elemental analysis using X-Ray Fluorescence (XRF). In addition, we developed a novel Road Dust Aerosolizer (RDA) sampler in order to collect PM_2.5 and PM₁₀ surface road dust in situ. This sampler aerosolizes dust from the road surface, simulating ambient road dust resuspension, resulting in measured PM composition and size more appropriately (and less labor-intensive) than those obtained from studies using bulk road dust sieved and re-suspended in the laboratory. Overall, our modified fine and coarse particle concentrators yielded good reproducibility between co-located samples and sufficient loading for trace elemental analysis. For particle mass concentration, we observed a relative error of 3% and 4% among pairs of filters for fine and coarse concentrators, respectively; confirming that the mass collected on an unweighted quartz filter in parallel with a Teflon filter will have the same PM mass as the weighed Teflon filter. For samples with elements that are well above the LOD, relative uncertainty values were between 5% and 10% for the fine and 3% and 10% for the coarse. Our results show that the RDA system has an excellent precision for mass and elements as well. The relative error for mass is 7% for PM₁₀ and 3% for PM_2.5 within pairs and ranged from 2 to10% for elements. In conclusion, we developed a method for collecting PM₁₀ and PM_2.5 near-road air and surface road dust for short durations, which allows investigation of the composition of direct (airborne) and indirect (re-suspended road dust) non-tailpipe vehicular emissions.

Implications: The methods we developed in this study allow the collection of one-hour PM10-2.5 and PM2.5–0.2 samples from near-road ambient air at several distances from the same roadway in 1 day, and collection of road dust directly from the road surface, with sufficient loading for trace elemental analysis. This will allow investigation of the composition of direct (airborne) and indirect (re-suspended road dust) vehicular emissions.

摘要

本研究在设计和建造的移动颗粒浓缩器平台 (MPCP) 中使用了细颗粒和粗颗粒浓缩器技术，以允许收集大量环境颗粒物，从而实现时间分辨的形态分析，这在使用传统方法时是不可行的。一小时的采样产生了足够的样品负载，用于使用 X 射线荧光 (XRF) 进行痕量元素分析。此外，我们开发了一种新型道路粉尘雾化器 (RDA) 采样器，以原位收集 PM _2.5和 PM ₁₀表面道路粉尘. 该采样器将道路表面的灰尘雾化，模拟周围道路灰尘的再悬浮，与使用在实验室中筛分和再悬浮的散装道路灰尘的研究中获得的测量结果相比，测量的 PM 成分和尺寸更合适（并且劳动强度更低）。总体而言，我们改进的细颗粒和粗颗粒浓缩器在同一位置的样品和足够的痕量元素分析负载之间产生了良好的重现性。对于颗粒质量浓度，我们观察到细和粗浓缩器的成对过滤器之间的相对误差分别为 3% 和 4%；确认在与特氟龙过滤器平行的未加权石英过滤器上收集的质量将与称重的特氟龙过滤器具有相同的 PM 质量。对于元素远高于 LOD 的样本，细粒的相对不确定度值介于 5% 和 10% 之间，粗粒的相对不确定度值介于 3% 和 10% 之间。我们的结果表明，RDA 系统对质量和元素也具有出色的精度。PM 的质量相对误差为 7%PM _2.5成对为₁₀ % 和 3 %，元素为 2% 至 10%。总之，我们开发了一种短期收集 PM ₁₀和 PM _2.5附近道路空气和地面道路灰尘的方法，可以调查直接（空气传播）和间接（重新悬浮的道路灰尘）非尾气排放的车辆的成分排放。

影响：我们在本研究中开发的方法允许在 1 天内从同一条道路不同距离的近路环境空气中收集一小时 PM10-2.5 和 PM2.5-0.2 样本，并直接从路面，有足够的负载进行微量元素分析。这将允许调查直接（空气传播）和间接（重新悬浮的道路灰尘）车辆排放物的成分。