Laboratory and field evaluation of the Aerosol Dynamics Inc. concentrator (ADIc) for aerosol mass spectrometry

Journal Article · 16 July 2019 · Atmospheric Measurement Techniques (Online)

DOI: https://doi.org/10.5194/amt-12-3907-2019 · OSTI ID:1542678

Saarikoski, Sanna ^[1]; Williams, Leah R. ^[2]; Spielman, Steven R. ^[3]; Lewis, Gregory S. ^[3]; Eiguren-Fernandez, Arantzazu ^[3]; Aurela, Minna  ^[1]; Hering, Susanne V.  ^[3]; Teinilä, Kimmo ^[1]; Croteau, Philip ^[2]; Jayne, John T. ^[2]; Hohaus, Thorsten  ^[2]; Worsnop, Douglas R. ^[2]; Timonen, Hilkka ^[1]

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1. Finnish Meteorological Inst., Helsinki (Finland). Atmospheric Composition Research
2. Aerodyne Research, Inc., Billerica, MA (United States). Center for Aerosol and Cloud Chemistry
3. Aerosol Dynamics Inc., Berkeley, CA (United States)

An air-to-air ultrafine particle concentrator (Aerosol Dynamics Inc.concentrator; ADIc) has been designed to enhance online chemicalcharacterization of ambient aerosols using aerosol mass spectrometry. The ADIcemploys a three-stage, moderated water-based condensation growth tubecoupled to an aerodynamic focusing nozzle to concentrate fine particles intoa portion of the flow. The system can be configured to sample between1.0 and 1.7 L min^-1, with an output concentrated flow between 0.08 and 0.12 L min^-1, resulting in a theoretical concentration factor (sampleflow / output flow) ranging from 8 to 21. Laboratory tests with monodisperseparticles show that the ADIc is effective for particles as small as 10 nm.Laboratory experiments conducted with the Aerosol Mass Spectrometer (AMS)showed no shift in the particle size with the ADIc, as measured by the AMSparticle time-of-flight operation. The ADIc-AMS system was operated unattended over a1-month period near Boston, Massachusetts. Comparison to a parallel AMSwithout the concentrator showed concentration factors of 9.7±0.15and 9.1±0.1 for sulfate and nitrate, respectively, when operatedwith a theoretical concentration factor of 10.5±0.3. Theconcentration factor of organics was lower, possibly due to the presence oflarge particles from nearby road-paving operations and a difference inaerodynamic lens cutoff between the two AMS instruments. Another fielddeployment was carried out in Helsinki, Finland. Two ~10 dmeasurement periods showed good correlation for the concentrations oforganics, sulfate, nitrate and ammonium measured with an Aerosol ChemicalSpeciation Monitor (ACSM) with the ADIc and a parallel AMS without theconcentrator. Additional experiments with an AMS alternating between theADIc and a bypass line demonstrated that the concentrator did notsignificantly change the size distribution or the chemistry of the ambientaerosol particles.

• Research Organization: Aerosol Dynamics, Inc., Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: SC0004698
• OSTI ID: 1542678
• Alternate ID(s): OSTI ID: 1610746
• Journal Information: Atmospheric Measurement Techniques (Online), Vol. 12, Issue 7; ISSN 1867-8548
• Publisher: European Geosciences UnionCopyright Statement
• Country of Publication: United States
• Language: English