Journal cover Journal topic
Atmospheric Measurement Techniques An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.248 IF 3.248
  • IF 5-year value: 3.650 IF 5-year 3.650
  • CiteScore value: 3.37 CiteScore 3.37
  • SNIP value: 1.253 SNIP 1.253
  • SJR value: 1.869 SJR 1.869
  • IPP value: 3.29 IPP 3.29
  • h5-index value: 47 h5-index 47
  • Scimago H index value: 60 Scimago H index 60
Volume 10, issue 8 | Copyright
Atmos. Meas. Tech., 10, 2897-2921, 2017
https://doi.org/10.5194/amt-10-2897-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 15 Aug 2017

Research article | 15 Aug 2017

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

Weiwei Hu1,2, Pedro Campuzano-Jost1,2, Douglas A. Day1,2, Philip Croteau3, Manjula R. Canagaratna3, John T. Jayne3, Douglas R. Worsnop3, and Jose L. Jimenez1,2 Weiwei Hu et al.
  • 1Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado at Boulder, 216 UCB, Boulder, CO 80309, USA
  • 2Department of Chemistry & Biochemistry, University of Colorado at Boulder, 216 UCB, Boulder, CO 80309, USA
  • 3Aerodyne Research, Inc., Billerica, Massachusetts, USA

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. 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 (Tv ∼ 200–800°C) on the detected fragments, CE and size distributions are investigated. A Tv 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 species 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 NaNO3. . 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.

Publications Copernicus
Download
Short summary
Aerosol mass spectrometers (AMS) from ARI are used widely to measure the non-refractory species in PM1. Recently, a new capture vapourizer (CV) has been designed to reduce the need for a bounce-related CE correction in the commonly used standard vapourizer (SV) installed in AMS. To test the CV, the fragments, CE and size distributions of four pure inorganic species in the CV-AMS are investigated in various laboratory experiments. Results from the co-located SV-AMS are also shown as a comparison.
Aerosol mass spectrometers (AMS) from ARI are used widely to measure the non-refractory species...
Citation
Share