Water-based condensation particle counters for environmental monitoring of ultrafine particles
Water-based condensation particle counters for environmental monitoring of ultrafine particles
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DOI：
10.1080/10473289.2006.10464520
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发表时间：
2006-04-01
影响因子：
2.7
通讯作者：
Oberreit, DR
中科院分区：
文献类型：
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作者：
Liu, W;Kaufman, SL;Oberreit, DR
TSI Inc. （Shoreview， MN）推出了三种新型水基冷凝颗粒计数器（WCPCS），设计用于检测空气中大于2.5 nm（型号3786），5 nm（型号3785）和10或20 nm（型号3782）的颗粒。这些wcpc非常适合于空气中超细颗粒数量浓度的实时环境监测。他们独特的设计包括使用水作为工作流体而不是酒精。水无气味，随时可用，并消除了在潮湿环境中操作时水凝结和吸收到酒精工作液中的问题。在这项研究中，表征了三种TSI WCPCs对几种气溶胶成分的性能，包括蔗糖、盐（NaCl）、癸二酸二辛酯（DOS）、邻苯二甲酸二辛酯（DOP）、砂油（聚α -烯烃）、银、杂质残留颗粒和环境气溶胶颗粒。使用纳米差分迁移率分析仪（nano- dma；型号3085，TSI Inc.）选择所有颗粒的大小，以创建单分散的挑战气溶胶。将挑战气溶胶与干净的化妆流混合均匀，并分为WCPC和参考仪器，以确定WCPC的计数效率。对于3785 WCPC模型，确定了D-50（即计数效率为50%的颗粒直径），盐颗粒为3.1 nm，蔗糖和环境颗粒为4.7 nm，银颗粒为5.6 nm，超纯油颗粒为> 50 nm。当油被轻微污染时，对油滴的敏感性显著增加（D-50 < 10 nm）。3786型超细水基CPC （UWCPC）对杂质残留颗粒的D-50为2.4 nm。型号3782 WCPC的D50为10.8（标称设置为10 nm）或19.8 nm（标称设置为20 nm）的蔗糖颗粒。所有三个wcpc的响应时间都小于2或3秒，因此能够检测快速变化的事件。
TSI Inc. (Shoreview, MN) has introduced three new waterbased condensation particle counters (WCPCS) that were designed, to detect airborne particles larger than 2.5 nm (model 3786), 5 nm (model 3785), and either 10 or 20 nm (model 3782). These WCPCs are well suited for real-time, environmental monitoring of number concentration of airborne ultrafine particles. Their unique design incorporates the use of water as the working fluid instead of alcohol. Water is odor free, readily available, and eliminates the problem of water condensation and absorption into alcohol working fluids during operation in humid environments. In this study, the performance of three TSI WCPCs was characterized for several aerosol compositions, including sucrose, salt (NaCl), dioctyl sebacate (DOS), dioctyl phthalate (DOP), emery oil (poly-alpha-olefin), silver, impurity residue particles, and ambient aerosol particles. All particles were size selected using a nano differential mobility analyzer (nano-DMA; model 3085, TSI Inc.) to create monodisperse challenge aerosols. The challenge aerosol was mixed uniformly With clean makeup flow and split into a WCPC and a reference instrument to determine the counting efficiency of the WCPC. For the model 3785 WCPC, the D-50 (i.e., the particle diameter with 50% counting efficiency) was de-, termined to be 3.1 nm for salt particles, 4.7 nm for sucrose and ambient particles, 5.6 nm for silver particles, and > 50 nm for ultrapure oil particles. The sensitivity to oil droplets increased dramatically (D-50 < 10 nm) when the oil was slightly contaminated. The D-50 of model 3786 ultrafine water-based CPC (UWCPC) was 2.4 nm for impurity residue particles. The D50 of the model 3782 WCPC was 10.8 (with a nominal setting of 10 nm) or 19.8 nm (with a nominal setting of 20 nm) for sucrose particles. All three WCPCs have response times of less than 2 or 3 sec and are therefore able to detect fast-changing events.