Warning message

Member access has been temporarily disabled. Please try again later.
The AVE Houston website is undergoing a major upgrade that began Friday, October 11th at 5:00 PM PDT. The new upgraded site will be available no later than Monday, October 21st. Until that time, the current site will be visible but logins are disabled.

 

Disclaimer: This material is being kept online for historical purposes. Though accurate at the time of publication, it is no longer being updated. The page may contain broken links or outdated information, and parts may not function in current web browsers. Visit https://espo.nasa.gov for information about our current projects.

 

Comparative Analysis of Urban Atmospheric Aerosol by Particle-Induced X-ray...

Johnson, K. S., A. Laskin, J. Jimenez-Palacios, V. Shutthanandan, L. T. Molina, D. Salcedo, K. Dzepina, and M. J. Molina (2008), Comparative Analysis of Urban Atmospheric Aerosol by Particle-Induced X-ray Emission (PIXE), Proton Elastic Scattering Analysis (PESA), and Aerosol Mass Spectrometry (AMS), Environ. Sci. Technol., 42, 6619-6624, doi:10.1021/es800393e.
Abstract: 

A multifaceted approach to atmospheric aerosol analysis is often desirable in field studies where an understanding of technical comparability among different measurement techniques is essential. Herein, we report quantitative intercomparisons of particle-inducedX-rayemission(PIXE)andprotonelasticscattering analysis (PESA), performed offline under a vacuum, with analysis by aerosol mass spectrometry (AMS) carried out in realtime 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 separatedintosulfateHandorganicHmassfractions,assuming the only major contributions were (NH4)2SO4 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 ∼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.

PDF of Publication: 
Download from publisher's website.
Research Program: 
Tropospheric Composition Program (TCP)