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Centre for Atmospheric Science

Aerosol Mass Spectrometry

The Aerodyne AMS

The Aerodyne Aerosol Mass Spectrometer (AMS) is a research instrument for the online quantitative measurement of aerosol composition. This has numerous applications the lab and field, providing measurements needed to study the relationship between aerosols and atmospheric chemistry, emissions sources, human exposure to pollutants, radiative transfer and cloud microphysics.

Aerosols are drawn into a vacuum chamber through an aerodynamic lens, which focuses particles between 30 and 800 nm into a tightly collimated beam. The particles impact on a tungsten surface, heated to 600 °C, which causes them to flash vaporise. The vapours are then ionised by 70 eV electrons and then analysed by mass spectrometry. A number of different types of mass spectrometer have been employed, using either Balzers/Pfeiffer quadrupole (Q-AMS) or Tofwerk orthogonal extraction time-of-flight (TOF-AMS) technology.

There are currently in excess of 80 AMSs worldwide and CAS has three; two compact time-of-flight (C-TOF) and one high resolution time-of-flight (HR-TOF). These have been used in the field and laboratory and one of the C-TOF instruments is regularly deployed on the Facility for Airborne Atmospheric Measurements (FAAM) BAe-146.

Because it uses thermal vaporisation, the instrument can only provide data on the nonrefractory fraction. In practice, it provides mass concentrations (in µg m-3) of particulate nitrate, sulphate, ammonium, organic matter and nonseasalt chloride, while not being able to detect elemental carbon, sea salt or dust. This is performed at a much higher time resolution (seconds to minutes) than can be achieved with traditional methods such as offline analysis of filter samples. In addition, a chopper wheel can be used to modulate the particle beam to provide data on the size of the particles under investigation. By inspecting the relative sizes of the organic peaks in the mass spectra, information can be gleaned regarding the functionality of the organic matter, which can in turn be used to infer potential sources and details of atmospheric chemical processing. This is further enhanced in the HR-AMS, which is capable of delivering data on elemental composition (e.g. ratio of carbon to oxygen).

More information on the AMS can be found at the following locations.
Aerodyne (http://www.aerodyne.com/products/aerosol_mass_spectrometer.htm)
Jimenez group:
General aerosol mass spectrometry information page (http://cires.colorado.edu/jimenez/ams.html)
AMS review paper (http://cires.colorado.edu/jimenez/Papers/Canagaratna_Review_Published.pdf)
Other scientific publications (http://cires.colorado.edu/jimenez/ams-papers.html)
TOF-AMS resources (http://cires.colorado.edu/jimenez-group/wiki/index.php?title=ToF-AMS_Main)
Q-AMS resources (http://cires.colorado.edu/jimenez-group/QAMSResources/)

AMS development activities at CAS

Since 1999, in partnership with Aerodyne Research Inc. and other groups worldwide, we have been actively involved in the ongoing hardware and software developments of the Aerodyne Aerosol Mass Spectrometer. These have improved the quality and the range of data that can be collected and facilitated the production of rich and quality-assured datasets by many groups worldwide (Canagaratna et al., 2007). Highlights of past developments include:


A development we are currently involved in is the development and application of the new soot particle (SP-) AMS. This is a new variant that uses a near infra red laser to selectively vaporise black carbon particles (as is used in the SP2). This is used to selectively study the composition of black carbon particles and their coatings. We performed the first field deployment of this instrument in Italy in 2009 and initial results have been promising (Allan et al., 2009).
Used in conjunction with conventional AMS and SP2 instruments, this instrument will be used to study the emission of BC particles and their transformation in the atmosphere, particularly with reference to their size distribution and mixing state. This is currently a major area of uncertainty in the study of the effects of pollution on climate and human health.



Alfarra, M. R.: Insights into atmospheric organic aerosols using an aerosol mass spectrometer, PhD Thesis, Department of Chemical Engineering, UMIST, Manchester, UK, 2004.
Alfarra, M. R., Coe, H., Allan, J. D., Bower, K. N., Boudries, H., Canagaratna, M. R., Jimenez, J. L., Jayne, J. T., Garforth, A., Li, S., and Worsnop, D. R.: Characterization of urban and rural organic particulate in the lower fraser valley using two aerodyne aerosol mass spectrometers, Atmos. Environ., 38, 5745-5758, 2004.
Allan, J. D., Jimenez, J. L., Williams, P. I., Alfarra, M. R., Bower, K. N., Jayne, J. T., Coe, H., and Worsnop, D. R.: Quantitative sampling using an aerodyne aerosol mass spectrometer - 1. Techniques of data interpretation and error analysis, J. Geophys. Res.-Atmos., 108, 4090, doi:10.1029/2002JD002358, 2003.
Allan, J. D.: An aerosol mass spectrometer: Instrument development, data analysis techniques and quantitative atmospheric particulate measurements, PhD thesis, Department of Physics, UMIST, Manchester, 2004.
Allan, J. D., Bower, K. N., Coe, H., Boudries, H., Jayne, J. T., Canagaratna, M. R., Millet, D. B., Goldstein, A. H., Quinn, P. K., Weber, R. J., and Worsnop, D. R.: Submicron aerosol composition at trinidad head, california, during itct 2k2: Its relationship with gas phase volatile organic carbon and assessment of instrument performance, J. Geophys. Res.-Atmos., 109, D23S24, doi:10.1029/2003JD004208, 2004a.
Allan, J. D., Coe, H., Bower, K. N., Alfarra, M. R., Delia, A. E., Jimenez, J. L., Middlebrook, A. M., Drewnick, F., Onasch, T. B., Canagaratna, M. R., Jayne, J. T., and Worsnop, D. R.: A generalised method for the extraction of chemically resolved mass spectra from aerodyne aerosol mass spectrometer data, J. Aerosol. Sci., 35, 909-922, 2004b.
Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., Aalto, P. P., Kulmala, M., Hyotylainen, T., Cavalli, F., and Laaksonen, A.: Size and composition measurements of background aerosol and new particle growth in a finnish forest during quest 2 using an aerodyne aerosol mass spectrometer, Atmos. Chem. Phys., 6, 315-327, 2006.
Allan, J. D., Coe, H., Kok, G. L., Baumgardner, D., Decesari, S., Lanconelli, C., Dall'Osto, M., Trimborn, A., Onasch, T., Jayne, J., and Worsnop, D.: Field deployment of a soot particle aerosol mass spectrometer (sp-ams) in the po valley, italy, AAAR 28th Annual Conference, Hyatt Regency Minneapolis, Minneapolis, Minnesota, USA, October 26-30, 2009.
Allen, G., Vaughan, G., Bower, K. N., Williams, P. I., Crosier, J., Flynn, M., Connolly, P., Hamilton, J. F., Lee, J. D., Saxton, J. E., Watson, N. M., Gallagher, M., Coe, H., Allan, J., Choularton, T. W., and Lewis, A. C.: Aerosol and trace-gas measurements in the darwin area during the wet season, J. Geophys. Res.-Atmos., 113, D06306, 10.1029/2007jd008706, 2008.
Canagaratna, M. R., Jayne, J. T., Jimenez, J. L., Allan, J. D., Alfarra, M. R., Zhang, Q., Onasch, T. B., Drewnick, F., Coe, H., Middlebrook, A., Delia, A., Williams, L. R., Trimborn, A. M., Northway, M. J., DeCarlo, P. F., Kolb, C. E., Davidovits, P., and Worsnop, D. R.: Chemical and microphysical characterization of ambient aerosols with the aerodyne aerosol mass spectrometer, Mass Spectrom. Rev., 26, 185-222, 2007.
Crosier, J., Allan, J. D., Coe, H., Bower, K. N., Formenti, P., and Williams, P. I.: Chemical composition of summertime aerosol in the po valley (italy), northern adriatic and black sea, Q. J. Roy. Meteor. Soc., 133, 61-75, DOI: 10.1002/qj.88, 2007a.
Crosier, J., Jimenez, J. L., Allan, J. D., Bower, K. N., Williams, P. I., Alfarra, M. R., Canagaratna, M. R., Jayne, J. T., Worsnop, D. R., and Coe, H.: Technical note: Description and use of the new jump mass spectrum mode of operation for the aerodyne quadrupole aerosol mass spectrometers (q-ams), Aerosol Sci. Technol., 41, 865-872, DOI: 10.1080/02786820701501899, 2007b.
Cross, E. S., Slowik, J. G., Davidovits, P., Allan, J. D., Worsnop, D. R., Jayne, J. T., Lewis, D. K., Canagaratna, M., and Onasch, T. B.: Laboratory and ambient particle density determinations using light scattering in conjunction with aerosol mass spectrometry, Aerosol Sci. Technol., 41, 343-359, 2007.
Matthew, B. M., Middlebrook, A. M., and Onasch, T. B.: Collection efficiencies in an aerodyne aerosol mass spectrometer as a function of particle phase for laboratory generated aerosols, Aerosol Sci. Technol., 42, 884-898, 2008.
Zhang, Q., Alfarra, M. R., Worsnop, D. R., Allan, J. D., Coe, H., Canagaratna, M. R., and Jimenez, J. L.: Deconvolution and quantification of hydrocarbon-like and oxygenated organic aerosols based on aerosol mass spectrometry, Environ. Sci. Technol., 39, 4938-4952, 2005.