K.S. Johnson (Author), A. Laskin (Author), Jose L. Jimenez (Author), V. Shutthanandan (Author), Luisa T. Molina (Author), Dara Salcedo (Author), Katja Džepina (Author), Mario J. Molina (Author)

Abstract

A multifaceted approach to atmospheric aerosol analysis is often desirable infield studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-induced X-ray emission (PIXE) and proton elastic scattering analysis (PESA), performed offline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in real-time during the MCMA-2003 Field Campaign in the Mexico City Metropolitan Area. Good agreement was observed for mass concentrations of PIXE-measured sulfur (assuming it was dominated by SO42-) and AMS-measured sulfate during most of the campaign. PESA-measured hydrogen mass was separated into sulfate H and organic H mass fractions, assuming the only major contributions were (NH4)(2)SO4 and organic compounds. Comparison of the organic H mass with AMS organic aerosol measurements indicates that about 75% of the mass of these species evaporated under a vacuum. However similar to 25% of the organics does remain under a vacuum, which is only possible with low-vapor-pressure compounds, and which supports the presence of high-molecular-weight or highly oxidized organics consistent with atmospheric aging. Approximately 10% of the chloride detected by AMS was measured by PIXE, possibly in the form of metal-chloride complexes, while the majority of Cl was likely present as more volatile species including NH4Cl. This is the first comparison of PIXE/PESA and AMS and, to our knowledge, also the first report of PESA hydrogen measurements for urban organic aerosols.

Keywords

organic aerosols;secondary organic aerosols;Mexico City;MCMA-2003 field campaign;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UNG - University of Nova Gorica
UDC: 54
COBISS: 59052035 Link will open in a new window
ISSN: 0013-936X
Views: 1452
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Other data

URN: URN:SI:UNG
Pages: str. 6619-6624
Volume: ǂVol. ǂ42
Issue: ǂiss. ǂ17
Chronology: 2008
DOI: 10.1021/es800393e
ID: 12757742