Title: Evaluation of the new capture vapourizer for aerosol mass spectrometers (AMS) through laboratory studies of inorganic species

Abstract

Aerosol mass spectrometers (AMSs) and Aerosol Chemical Speciation Monitors (ACSMs) commercialized by Aerodyne are widely used to measure the non-refractory species in submicron particles. With the standard vapourizer (SV) that is installed in all commercial instruments to date, the quantification of ambient aerosol mass concentration requires the use of the collection efficiency (CE) to correct for the loss of particles due to bounce. Thus, a new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction. Two high-resolution AMS instruments, one with a SV and one with a CV, were operated side by side in the laboratory. Four standard species, NH₄NO₃, NaNO₃, (NH₄)₂SO₄ and NH₄Cl, which typically constitute the majority of the mass of ambient submicron inorganic species, are studied. The effect of vapourizer temperature (T_v ∼ 200–800 °C) on the detected fragments, CE and size distributions are investigated. A T_v of 500–550 °C for the CV is recommended. In the CV, CE was identical (around unity) for more volatile species (e.g. NH₄NO₃) and comparable to or higher than the SV for less-volatile species (e.g. (NH₄)₂SO₄), demonstrating an improvement in CE for laboratory inorganic species in the CV. The detected relative intensities of fragments of NO₃ and SO₄ speciesmore » observed with the CV are different from those observed with the SV, and are consistent with additional thermal decomposition arising from the increased residence time and multiple collisions. Increased residence times with the CV also lead to broader particle size distribution measurements than with the SV. A method for estimating whether pure species will be detected in AMS sizing mode is proposed. Production of CO₂(g) from sampled nitrate on the vapourizer surface, which has been reported for the SV, is negligible for the CV for NH₄NO₃ and comparable to the SV for NaNO_3.. We observe an extremely consistent fragmentation for ammonium compared to very large changes for the associated anions. Together with other evidence, this indicates that it is unlikely that a major fraction of inorganic species vapourizes as intact salts in the AMS.« less

Authors:

Hu, Weiwei ^[1]; Campuzano-Jost, Pedro  ^[1];

• Search DOE PAGES for author "Campuzano-Jost, Pedro"
• Search DOE PAGES for ORCID "0000-0003-3930-010X"

Day, Douglas A. ^[1]; Croteau, Philip ^[2]; Canagaratna, Manjula R. ^[2]; Jayne, John T. ^[2]; Worsnop, Douglas R. ^[2]; Jimenez, Jose L.  ^[1]

• Search DOE PAGES for author "Jimenez, Jose L."
• Search DOE PAGES for ORCID "0000-0001-6203-1847"

---

+ Show Author Affiliations

1. Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in the Environmental Sciences (CIRES) and Dept. of Chemistry and Biochemistry
2. Aerodyne Research Inc., Billerica, MA (United States)

Publication Date:

Tue Aug 15 00:00:00 EDT 2017

Research Org.:

Univ. of Colorado, Boulder, CO (United States)

Sponsoring Org.:

Office of Science (SC), Biological and Environmental Research (BER). Earth and Environmental Systems Science Division; USDOE Office of Energy Efficiency and Renewable Energy (EERE); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA); National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States)

OSTI Identifier:

1375063

Alternate Identifier(s):

OSTI ID: 1425371

Grant/Contract Number:  

sc0011095; AGS-1360834; AGS-1243354; NNX15AT96G; SC0011105; SC0016559; NA13OAR4310063; SC0001673

Resource Type:

Published Article

Journal Name:

Atmospheric Measurement Techniques (Online)

Additional Journal Information:

Journal Name: Atmospheric Measurement Techniques (Online) Journal Volume: 10 Journal Issue: 8; Journal ID: ISSN 1867-8548

Publisher:

Copernicus Publications, EGU

Country of Publication:

Germany

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES