Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 7 2 2007 10.5194/acp-7-549-2007 http://www.atmos-chem-phys.net/7/549/2007/ http://www.atmos-chem-phys.net/7/549/2007/acp-7-549-2007.html http://www.atmos-chem-phys.net/7/549/2007/acp-7-549-2007.pdf 549 556 2007-01-30 Technical Note: Use of a beam width probe in an Aerosol Mass Spectrometer to monitor particle collection efficiency in the field D. Salcedo T. B. Onasch M. R. Canagaratna K. Dzepina J. A. Huffman J. T. Jayne D. R. Worsnop C. E. Kolb S. Weimer F. Drewnick J. D. Allan A. E. Delia J. L. Jimenez jose.jimenez@colorado.edu Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado at Boulder, CO, USA Center for Aerosol and Cloud Chemistry, Aerodyne Research Inc., Billerica, MA, USA Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO, USA Atmospheric Sciences Research Center, University at Albany, Albany, NY, USA Particle Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany Department of Physics, University of Manchester Institute of Science and Technology, Manchester, UK Program in Atmospheric and Oceanic Sciences, University of Colorado at Boulder, Boulder, CO, USA now at: EMPA, Duebendorf, Switzerland and Paul Scherrer Institute, Villigen, Switzerland Two Aerodyne Aerosol Mass Spectrometers (Q-AMS) were deployed in Mexico City, during the Mexico City Metropolitan Area field study (MCMA-2003) from 29 March&ndash;4 May 2003 to investigate particle concentrations, sources, and processes. We report the use of a particle beam width probe (BWP) in the field to quantify potential losses of particles due to beam broadening inside the AMS caused by particle shape (nonsphericity) and particle size. Data from this probe show that no significant mass of particles was lost due to excessive beam broadening; i.e. the shape- and size-related collection efficiency (<i>E<sub>s</sub></i>) of the AMS during this campaign was approximately one. Comparison of the BWP data from MCMA-2003 with other campaigns shows that the same conclusion holds for several other urban, rural and remotes sites. This means that the aerodynamic lens in the AMS is capable of efficiently focusing ambient particles into a well defined beam and onto the AMS vaporizer for particles sampled in a wide variety of environments. All the species measured by the AMS during MCMA-2003 have similar attenuation profiles which suggests that the particles that dominate the mass concentration were internally mixed most of the time. Only for the smaller particles (especially below 300 nm), organic and inorganic species show different attenuation versus particle size which is likely due to partial external mixing of these components. Changes observed in the focusing of the particle beam in time can be attributed, in part, to changes in particle shape (i.e. due to relative humidity) and size of the particles sampled. However, the relationships between composition, atmospheric conditions, and particle shape and size appear to be very complex and are not yet completely understood. 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. M., and Worsnop, D. R.: Characterization of Urban and Regional Organic Aerosols In the Lower Fraser Valley Using Two Aerodyne Aerosol Mass Spectrometers, Atmos. Environ., 38, 5745&ndash;5758, 2004. Allan, J. D., Alfarra, M. R., Bower, K. N., Coe, H., Jayne, J. T., Worsnop, D. R., Aalto, P. P., Kulmala, M., Hyötyläinen, 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&ndash;327, 2006a. 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, CA during ITCT 2K2, its relationship with gas phase volatile organic carbon and assessment of instrument performance, J. Geophys. Res., 109, D23S24, doi:10.1029/2003JD004208, 2004. DeCarlo, P. F., Slowik, J. G., Worsnop, D. R., Davidovits, P., and Jimenez, J. L.: Particle Morphology and Density Characterization by Combined Mobility and Aerodynamic Diameter Measurements. Part 1: Theory, Aerosol Sci. Technol., 38, 1185&ndash;1205, doi: 10.1080/027868290903907, 2004. Delia, A. E.: Real-Time Measurements of Non-Refractory Particle Composition and Interactions at Forested Sites, Ph.D. thesis, University of Colorado, Boulder, CO, 2004. Drewnick, F., Jayne, J. T., Canagaratna, M. R., Worsnop, D. R., and Demerjian, K. L.: Measurement of Ambient Aerosol Composition During the PMTACS-NY 2001 Using an Aerosol Mass Spectrometer. Part II: Chemically Speciated Mass Distributions, Aerosol Sci. Technol., 38, 104&ndash;117, 2004a. Drewnick, F., Schwab, J. J., Jayne, J. T., Canagaratna, M. R., Worsnop, D. R., and Demerjian, K. L.: Measurement of Ambient Aerosol Composition During the PMTACS-NY 2001 Using an Aerosol Mass Spectrometer. Part I: Mass concentrations, Aerosol Sci. Technol., 38, 92&ndash;103, doi:10.1080/02786820390229507, 2004b. Hogrefe, O., Schwab, J. J., Drewnick, F., Lala, G. G., Peters, S., Demerjian, K. L., Rhoads, K., Felton, H. D., Rattigan, O. V., Husain, L., and Dutkiewicz, V. A.: Semicontinuous PM$_2.5$ Sulfate and Nitrate Measurements at an Urban and a Rural Location in New York: PMTACS-NY Summer 2001 and 2002 Campaigns, J. Air. Waste Manage., 54, 1040&ndash;1060, 2004. Huffman, J. A., Jayne, J. T., Drewnick, F., Aiken, A. C., Onasch, T., Worsnop, D. R., and Jimenez, J. L.: Design, Modeling, Optimization, and Experimental Tests of a Particle Beam Width Probe for the Aerodyne Aerosol Mass Spectrometer, Aerosol Sci. Technol., 39, 1143&ndash;1163, 2005. Jayne, J. T., Leard, D. C., Zhang, X., Davidovits, P., Smith, K. A., Kolb, C. E., and Worsnop, D. R.: Development of an Aerosol Mass Spectrometer for Size and Composition Analysis of Submicron Particles, Aerosol Sci. Technol., 33, 49&ndash;70, 2000. Jimenez, J. L., Jayne, J. T., Shi, Q., Kolb, C. E., Worsnop, D. R., Yourshaw, I., Seinfeld, J. H., Flagan, R. C., Zhang, X., Smith, K. A., Morris, J., and Davidovits, P.: Ambient aerosol sampling using the Aerodyne Aerosol Mass Spectrometer, J. Geophys. Res., 108, 8425, doi:10.1029/2001JD001213, 2003. Johnson, K. S., Zuberi, B., Molina, L. T., Molina, M. J., Iedema, M. J., Cowin, J. P., Gaspar, D. J., Wang, C., and Laskin, A.: Processing of soot in an urban environment: case study from the Mexico City Metropolitan Area, Atmos. Chem. Phys., 5, 3033&ndash;3043, 2005. Kolb, C. E., Herndon, S. C., McManus, J. B., Shorter, J. H., Zahniser, M. S., Nelson, D. D., Jayne, J. T., Canagaratna, M. R., and Worsnop, D. R.: Mobile Laboratory with Rapid Response Instruments for Real-Time Measurements of Urban and Regional Trace Gas and Particulate Distributions and Emission Source Characteristics, Environ. Sci. Technol., 38, 5694&ndash;5703, 2004. Liu, P., Ziemann, P. J., Kittelson, D. B., and McMurry, P. H.: Generating particle beams of controlled dimensions and divergence. 2. Experimental evaluation of particle motion in aerodynamic lenses and nozzle expansions, Aerosol Sci. Technol., 22, 314&ndash;324, 1995. Salcedo, D., Onasch, T. B., Dzepina, K., Canagaratna, M. R., Zhang, Q., Huffman, J. A., DeCarlo, P. F., Jayne, J. T., Mortimer, P., Worsnop, D. R., Kolb, C. E., Johnson, K. S., Zuberi, B., Marr, L. C., Volkamer, R., Molina, L. T., Molina, M. J., Cardenas, B., Bernabé, R. M., Márquez, C., Gaffney, J. S., Marley, N. A., Laskin, A., Shutthanandan, V., Xie, Y., Brune, W., Lesher, R., Shirley, T., and Jimenez, J. L.: Characterization of ambient aerosols in Mexico City during the MCMA-2003 campaign with Aerosol Mass Spectrometry: results from the CENICA Supersite, Atmos. Chem. Phys., 6, 925&ndash;946, 2006. Schwab, J. J., Felton, H. D., Rattigan, O. V., and Demerian, K. L.: New York State Urban and Rural Measurements of Continuous PM2.5 Mass by FDMS, TEOM, and BAM., J. Air. Waste Manage., 56, 372&ndash;383, 2006. Wang, X., Kruis, F. E., and McMurry, P. H.: Aerodynamic Focusing of Nanoparticles: I. Guidelines for Designing Aerodynamic Lenses for Nanoparticles, Aerosol Sci. Technol., 39, 611&ndash;623, 2005. Weimer, S., Drewnick, F., Hogrefe, O., Schwab, J. J., Rhoads, K., Orsini, D., Canagaratna, M. R., Worsnop, D. R., and Demerjian, K. L.: Size-Selective Non-Refractory Ambient Aerosol Measurements during the PMTACS-NY 2004 Winter Intensive in New York City, J. Geophys. Res., 111, D18305, doi:10.1029/2006JD007215, 2006. 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&ndash;4952, doi:10.1021/es048568l, 2005a. Zhang, Q., Canagaratna, M. R., Jayne, J. T., Worsnop, D. R., and Jimenez, J. L.: Time and Size-Resolved Chemical Composition of Submicron Particles in Pittsburgh. Implications for Aerosol Sources and Processes, J. Geophys. Res., 110, D07S09, doi:10.1029/2004JD004649, 2005b. Zhang, Q., Worsnop, D. R., Canagaratna, M. R., and Jimenez, J. L.: Hydrocarbon-like and Oxygenated Organic Aerosols in Pittsburgh: Insights into Sources and Processes of Organic Aerosols, Atmos. Chem. Phys., 5, 3289&ndash;3311, 2005c. Zhang, X., Smith, K. A., Worsnop, D. R., Jimenez, J. L., Jayne, J. T., Kolb, C. E., Morris, J., and Davidovits, P.: Characterization of Particle Beam Collimation. Part II: Integrated Aerodynamic Lens-Nozzle System, Aerosol Sci. Technol., 38, 619&ndash;638, 2004.