A comparison of particle mass spectrometers during the 1999 Atlanta Supersite Project

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Read Full Article (file size: 481496 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D7, 8424, doi:10.1029/2001JD000660, 2003 A comparison of particle mass spectrometers during the 1999 Atlanta Supersite Project Ann M. Middlebrook NOAA Aeronomy Laboratory, Boulder, Colorado, USA Daniel M. Murphy NOAA Aeronomy Laboratory, Boulder, Colorado, USA Shan-Hu Lee NOAA Aeronomy Laboratory, Boulder, Colorado, USA David S. Thomson NOAA Aeronomy Laboratory, Boulder, Colorado, USA Kimberly A. Prather Department of Chemistry, University of California, Riverside, California, USA Ryan J. Wenzel Department of Chemistry, University of California, Riverside, California, USA Don-Yuan Liu Department of Chemistry, University of California, Riverside, California, USA Denis J. Phares Departments of Mechanical Engineering and Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA Kevin P. Rhoads Departments of Mechanical Engineering and Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA Anthony S. Wexler Departments of Mechanical Engineering and Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA Murray V. Johnston Departments of Mechanical Engineering and Chemistry and Biochemistry, University of Delaware, Newark, Delaware, USA José L. Jimenez Aerodyne Research Incorporated, Billerica, Massachusetts, USA John T. Jayne Aerodyne Research Incorporated, Billerica, Massachusetts, USA Douglas R. Worsnop Aerodyne Research Incorporated, Billerica, Massachusetts, USA Ivan Yourshaw Departments of Environmental Engineering Science and Chemical Engineering, California Institute of Technology, Pasadena, California, USA John H. Seinfeld Departments of Environmental Engineering Science and Chemical Engineering, California Institute of Technology, Pasadena, California, USA Richard C. Flagan Departments of Environmental Engineering Science and Chemical Engineering, California Institute of Technology, Pasadena, California, USA Abstract During the Atlanta Supersite Project, four particle mass spectrometers were operated together for the first time: NOAA's Particle Analysis by Laser Mass Spectrometer (PALMS), University of California at Riverside's Aerosol Time-of-Flight Mass Spectrometer (ATOFMS), University of Delaware's Rapid Single-Particle Mass Spectrometer II (RSMS-II), and Aerodyne's Aerosol Mass Spectrometer (AMS). Although these mass spectrometers are generally classified as similar instruments, they clearly have different characteristics due to their unique designs. One primary difference is related to the volatilization/ionization method: PALMS, ATOFMS, and RSMS-II utilize laser desorption/ionization, whereas particles in the AMS instrument are volatilized by impaction onto a heated surface with the resulting components ionized by electron impact. Thus mass spectral data from the AMS are representative of the ensemble of particles sampled, and those from the laser-based instruments are representative of individual particles. In addition, the AMS instrument cannot analyze refractory material such as soot, sodium chloride, and crustal elements, and some sulfate or water-rich particles may not always be analyzed with every laser-based instrument. A main difference among the laser-based mass spectrometers is that the RSMS-II instrument can obtain size-resolved single particle composition information for particles with aerodynamic diameters as small as 15 nm. The minimum sizes analyzed by ATOFMS and PALMS are 0.2 and about 0.35 μm, respectively, in aerodynamic diameter. Furthermore, PALMS, ATOFMS, and RSMS-II use different laser ionization conditions. Despite these differences the laser-based instruments found similar individual particle classifications, and their relative fractions among comparable sized particles from Atlanta were broadly consistent. Finally, the AMS measurements of the nitrate/sulfate mole ratio were highly correlated with composite measurements (r² = 0.93). In contrast, the PALMS nitrate/sulfate ion ratios were only moderately correlated (r² ∼ 0.7). Published 10 April 2003. Index Terms: 0305 Atmospheric Composition and Structure: Aerosols and particles (0345, 4801); 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0394 Atmospheric Composition and Structure: Instruments and techniques. Read Full Article (file size: 481496 bytes) Cited by Citation: Middlebrook, A. M., et al. (2003), A comparison of particle mass spectrometers during the 1999 Atlanta Supersite Project, J. Geophys. Res., 108(D7), 8424, doi:10.1029/2001JD000660. Copyright 2003 by the American Geophysical Union.

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