Martins Marco, Lawrence Joy, Ferguson Stephen, Wolfson Jack M, Koutrakis Petros
Department of Environmental Health, Harvard T.H. Chan School of Public Health , Boston, Massachusetts, USA.
J Air Waste Manag Assoc. 2021 Feb;71(2):118-128. doi: 10.1080/10962247.2020.1853626.
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 and PM surface road dust . 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 PM and 3% for PM within pairs and ranged from 2 to10% for elements. In conclusion, we developed a method for collecting PM and PM 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. : 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.
本研究在一个设计并制造的移动颗粒浓缩平台（MPCP）中使用了细颗粒物和粗颗粒物浓缩技术，该平台能够收集大量环境颗粒物，从而实现时间分辨形态分析，而这用传统方法是不可行的。一小时的采样产生了足够的样品负载量，可用于使用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扬尘雾化器（RDA）采样器，以收集颗粒物和颗粒物表面的道路扬尘。该采样器将路面灰尘雾化，模拟环境道路扬尘再悬浮，从而使测得的颗粒物成分和粒径比使用在实验室中筛分并重新悬浮的散装道路灰尘的研究结果更合适（且劳动强度更低）。总体而言，我们改进后的细颗粒物和粗颗粒物浓缩器在共置样品之间产生了良好的重现性，并为痕量元素分析提供了足够的负载量。对于颗粒物质量浓度，我们观察到细颗粒物和粗颗粒物浓缩器的成对滤膜之间的相对误差分别为3%和4%；这证实了与聚四氟乙烯滤膜平行放置的未称重石英滤膜上收集的质量与称重后的聚四氟乙烯滤膜上的颗粒物质量相同。对于元素含量远高于检测限的样品，细颗粒物的相对不确定度值在5%至10%之间，粗颗粒物的相对不确定度值在3%至10%之间。我们的结果表明，RDA系统在质量和元素方面也具有出色的精密度。成对样品中PM的质量相对误差为7%，PM的质量相对误差为3%，元素的相对误差范围为2%至10%。总之，我们开发了一种在短时间内收集道路附近空气中的PM和PM以及路面道路扬尘的方法，这使得对直接（空气传播）和间接（再悬浮道路扬尘）非尾气车辆排放成分的研究成为可能。：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道路附近环境空气中收集一小时的PM10 - 2.5和PM2.5 - 0.2样品，并直接从路面收集道路扬尘，且具有足够的负载量用于痕量元素分析。这将使得对直接（空气传播）和间接（再悬浮道路扬尘）车辆排放成分的研究成为可能。
