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Title: A fast integrated mobility spectrometer for rapid measurement of sub-micrometer aerosol size distribution, Part II: Experimental characterization

Abstract

A Fast Integrated Mobility Spectrometer (FIMS) with a wide dynamic size range has been developed for rapid aerosol size distribution measurements. The design and model evaluation of the FIMS are presented in the preceding paper (Paper I), and this paper focuses on the experimental characterization of the FIMS. Monodisperse aerosol with diameter ranging from 8 to 600 nm was generated using Differential Mobility Analyzer (DMA), and was measured by the FIMS in parallel with a Condensation Particle Counter (CPC). The mean particle diameter measured by the FIMS is in good agreement with the DMA centroid diameter. Comparison of the particle concentrations measured by the FIMS and CPC indicates the FIMS detection efficiency is essentially 100% for particles with diameters of 8 nm or larger. For particles smaller than 20 nm or larger than 200 nm, FIMS transfer function and resolution can be well represented by the calculated ones based on simulated particle trajectories in the FIMS. For particles between 20 and 200 nm, the FIMS transfer function is boarder than the calculated, likely due to non-ideality of the electric field, including edge effects near the end of the electrode, which are not represented by the 2-D electric field used tomore » simulate particle trajectories.« less

Authors:
 [1];  [1];  [1];  [2];  [3];  [1];  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Environmental and Climate Sciences Dept.
  2. Aerosol Dynamics Inc., Berkeley, CA (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Instrumentation Division
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1362164
Report Number(s):
BNL-113921-2017-JA
Journal ID: ISSN 0021-8502; R&D Project: 2016-BNL-EE630EECA-Budg; KP1701000
Grant/Contract Number:
SC0012704
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Aerosol Science
Additional Journal Information:
Journal Volume: 113; Journal ID: ISSN 0021-8502
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Fast Integrated Mobility Spectrometer; Aerosol size distribution; High time resolution; Electrical mobility; Transfer function; Mobility resolution

Citation Formats

Wang, Jian, Pikridas, Michael, Pinterich, Tamara, Spielman, Steven R., Tsang, Thomas, McMahon, Andrew, and Smith, Scott. A fast integrated mobility spectrometer for rapid measurement of sub-micrometer aerosol size distribution, Part II: Experimental characterization. United States: N. p., 2017. Web. doi:10.1016/j.jaerosci.2017.05.001.
Wang, Jian, Pikridas, Michael, Pinterich, Tamara, Spielman, Steven R., Tsang, Thomas, McMahon, Andrew, & Smith, Scott. A fast integrated mobility spectrometer for rapid measurement of sub-micrometer aerosol size distribution, Part II: Experimental characterization. United States. doi:10.1016/j.jaerosci.2017.05.001.
Wang, Jian, Pikridas, Michael, Pinterich, Tamara, Spielman, Steven R., Tsang, Thomas, McMahon, Andrew, and Smith, Scott. Thu . "A fast integrated mobility spectrometer for rapid measurement of sub-micrometer aerosol size distribution, Part II: Experimental characterization". United States. doi:10.1016/j.jaerosci.2017.05.001.
@article{osti_1362164,
title = {A fast integrated mobility spectrometer for rapid measurement of sub-micrometer aerosol size distribution, Part II: Experimental characterization},
author = {Wang, Jian and Pikridas, Michael and Pinterich, Tamara and Spielman, Steven R. and Tsang, Thomas and McMahon, Andrew and Smith, Scott},
abstractNote = {A Fast Integrated Mobility Spectrometer (FIMS) with a wide dynamic size range has been developed for rapid aerosol size distribution measurements. The design and model evaluation of the FIMS are presented in the preceding paper (Paper I), and this paper focuses on the experimental characterization of the FIMS. Monodisperse aerosol with diameter ranging from 8 to 600 nm was generated using Differential Mobility Analyzer (DMA), and was measured by the FIMS in parallel with a Condensation Particle Counter (CPC). The mean particle diameter measured by the FIMS is in good agreement with the DMA centroid diameter. Comparison of the particle concentrations measured by the FIMS and CPC indicates the FIMS detection efficiency is essentially 100% for particles with diameters of 8 nm or larger. For particles smaller than 20 nm or larger than 200 nm, FIMS transfer function and resolution can be well represented by the calculated ones based on simulated particle trajectories in the FIMS. For particles between 20 and 200 nm, the FIMS transfer function is boarder than the calculated, likely due to non-ideality of the electric field, including edge effects near the end of the electrode, which are not represented by the 2-D electric field used to simulate particle trajectories.},
doi = {10.1016/j.jaerosci.2017.05.001},
journal = {Journal of Aerosol Science},
number = ,
volume = 113,
place = {United States},
year = {Thu Jun 08 00:00:00 EDT 2017},
month = {Thu Jun 08 00:00:00 EDT 2017}
}

Journal Article:
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  • This study discusses, a fast integrated mobility spectrometer (FIMS) was previously developed to characterize submicron aerosol size distributions at a frequency of 1 Hz and with high size resolution and counting statistics. However, the dynamic size range of the FIMS was limited to one decade in particle electrical mobility. It was proposed that the FIMS dynamic size range can be greatly increased by using a spatially varying electric field. This electric field creates regions with drastically different field strengths in the separator, such that particles of a wide diameter range can be simultaneously classified and subsequently measured. A FIMS incorporatingmore » this spatially varying electric field is developed. This paper describes the theoretical frame work and numerical simulations of the FIMS with extended dynamic size range, including the spatially varying electric field, particle trajectories, activation of separated particles in the condenser, and the transfer function, transmission efficiency, and mobility resolution. The influences of the particle Brownian motion on FIMS transfer function and mobility resolution are examined. The simulation results indicate that the FIMS incorporating the spatially varying electric field is capable of measuring aerosol size distribution from 8 to 600 nm with high time resolution. As a result, the experimental characterization of the FIMS is presented in an accompanying paper.« less
  • This study discusses, a fast integrated mobility spectrometer (FIMS) was previously developed to characterize submicron aerosol size distributions at a frequency of 1 Hz and with high size resolution and counting statistics. However, the dynamic size range of the FIMS was limited to one decade in particle electrical mobility. It was proposed that the FIMS dynamic size range can be greatly increased by using a spatially varying electric field. This electric field creates regions with drastically different field strengths in the separator, such that particles of a wide diameter range can be simultaneously classified and subsequently measured. A FIMS incorporatingmore » this spatially varying electric field is developed. This paper describes the theoretical frame work and numerical simulations of the FIMS with extended dynamic size range, including the spatially varying electric field, particle trajectories, activation of separated particles in the condenser, and the transfer function, transmission efficiency, and mobility resolution. The influences of the particle Brownian motion on FIMS transfer function and mobility resolution are examined. The simulation results indicate that the FIMS incorporating the spatially varying electric field is capable of measuring aerosol size distribution from 8 to 600 nm with high time resolution. As a result, the experimental characterization of the FIMS is presented in an accompanying paper.« less
  • We present rapid measurement of submicron particle size distributions enables the characterization of aerosols with fast changing properties, and is often necessary for measurements onboard mobile platforms (e.g., research aircraft). Aerosol mobility size distribution is commonly measured by a scanning mobility particle sizer (SMPS), which relies on voltage scanning or stepping to classify particles of different sizes, and may take up to several minutes to obtain a complete size spectrum of aerosol particles. The recently developed fast integrated mobility spectrometer (FIMS) with enhanced dynamic size range classifies and detects particles from 10 to ~600 nm simultaneously, allowing submicron aerosol mobilitymore » size distributions to be captured at a time resolution of 1 second. In this study, we present a detailed data inversion routine for deriving aerosol size distribution from FIMS measurements. The inversion routine takes into consideration the FIMS transfer function, particle penetration efficiency in the FIMS, and multiple charging of aerosols. The accuracy of the FIMS measurement is demonstrated by comparing parallel FIMS and SMPS measurements of stable aerosols with a wide range of size spectrum shapes, including ambient aerosols and aerosols classified by a differential mobility analyzer (DMA). The FIMS and SMPS-derived size distributions show excellent agreements for all aerosols tested. In addition, total number concentrations of ambient aerosols were integrated from 1 Hz FIMS size distributions, and compared with those directly measured by a condensation particle counter (CPC) operated in parallel. Finally, the integrated and measured total particle concentrations agree well within 5%.« less
  • We report a new scanning mobility particle spectrometer (SMPS) for measuring number size distributions of particles down to {approx}1 nm mobility diameter. This SMPS includes an aerosol charger, a TSI 3085 nano differential mobility analyzer (nanoDMA), an ultrafine condensation particle counter (UCPC) using diethylene glycol (DEG) as the working fluid, and a conventional butanol CPC (the 'booster') to detect the small droplets leaving the DEG UCPC. The response of the DEG UCPC to negatively charged sodium chloride particles with mobility diameters ranging from 1-6 nm was measured. The sensitivity of the DEG UCPC to particle composition was also studied bymore » comparing its response to positively charged 1.47 and 1.70 nm tetra-alkyl ammonium ions, sodium chloride, and silver particles. A high resolution differential mobility analyzer was used to generate the test particles. These results show that the response of this UCPC to sub-2 nm particles is sensitive to particle composition. The applicability of the new SMPS for atmospheric measurement was demonstrated during the Nucleation and Cloud Condensation Nuclei (NCCN) field campaign (Atlanta, Georgia, summer 2009). We operated the instrument at saturator and condenser temperatures that allowed the efficient detection of sodium chloride particles but not of air ions having the same mobility. We found that particles as small as 1 nm were detected during nucleation events but not at other times. Factors affecting size distribution measurements, including aerosol charging in the 1-10 nm size range, are discussed. For the charger used in this study, bipolar charging was found to be more effective for sub-2 nm particles than unipolar charging. No ion induced nucleation inside the charger was observed during the NCCN campaign.« less
  • We present a Humidity-controlled Fast Integrated Mobility Spectrometer (HFIMS) for rapid particle hygroscopicity measurements. The HFIMS consists of a differential mobility analyzer (DMA), a relative humidity (RH) control unit and a water-based FIMS (WFIMS) coupled in series. The WFIMS (Pinterich et al., 2017) combines the Fast Integrated Mobility Spectrometer (Kulkarni and Wang, 2006a, b) with laminar flow water condensation methodologies (Hering and Stolzenburg, 2005; Spielman et al., 2017). Inside the WFIMS, particles of different electrical mobilities are spatially separated in an electric field, condensationally enlarged and imaged to provide 1-Hz measurements of size distribution spanning a factor of ~ 3more » in particle diameter, sufficient to cover the entire range of growth factor for atmospheric aerosol particles at 90 % RH. By replacing the second DMA of a traditional hygroscopicity tandem DMA (HTDMA) system with the WFIMS, the HFIMS greatly increases the speed of particle growth factor measurement. The performance of the HFIMS was evaluated using NaCl particles with well-known hygroscopic growth behavior, and further through measurements of ambient aerosols. Results show that HFIMS can reproduce, within 2 % the literature values for hygroscopic growth of NaCl particles. NaCl deliquescence was observed between 76 % and 77 % RH in agreement with the theoretical value of 76.5 % (Ming and Russell, 2001), and efflorescence relative humidity (43 %) was found to lie within the RH range of 41 % to 56 % reported in the literature. Ambient data indicate that HFIMS can measure the hygroscopic growth of five standard dry particle sizes ranging from 35 to 165 nm within less than three minutes, which makes it about an order of magnitude faster than traditional HTDMA systems.« less