Characterization of Ambient Aerosols in Mexico City during the MCMA-2003 Campaign using an Aerosol Mass Spectrometer: Overall Trends and the Inorganic Component

HR: 15:16h
AN: A23D-08 [Abstracts]
TI: Characterization of Ambient Aerosols in Mexico City during the MCMA-2003 Campaign using an Aerosol Mass Spectrometer: Overall Trends and the Inorganic Component
AU: * Salcedo, D
EM: dara@ciq.uaem.mx
AF: Universidad Autonoma del Estado de Morelos Centro de Investigaciones Quimcas, Av. Universidad #1001, Cuernavaca, Mor 62210 Mexico
AU: Dzepina, K
EM: katja.dzepina@colorado.edu
AF: University of Colorado-Boulder, UCB 216, Boulder, CO 80309 United States
AU: Huffman, A
EM: alex.huffman@colorado.edu
AF: University of Colorado-Boulder, UCB 216, Boulder, CO 80309 United States
AU: De Carlo, P
EM: peter.decarlo@colorado.edu
AF: University of Colorado-Boulder, UCB 216, Boulder, CO 80309 United States
AU: Onasch, T B
EM: onasch@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Mortimer, P
EM: mortimer@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Jayne, J T
EM: jayne@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Canagaratna, M
EM: mrcana@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Worsnop, D R
EM: worsnop@aerodyne.com
AF: Aerodyne Research, Inc., 45 Manning Road, Billerica, MA 01821 United States
AU: Marr, L
EM: lmarr@vt.edu
AF: Virginia Polytechnic Institute and State University, 411 Durham Hall, Blacksburg, VA 24061 United States
AU: Marr, L
EM: lmarr@vt.edu
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Molina, L T
EM: ltmolina@mit.edu
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Molina, M J
EM: mmolina@mit.edu
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Cardenas, B
EM: bcar@xanum.uam.mx
AF: CENICA, PerifＳico 5000, Mexico, DF 04530 Mexico
AU: Bernabe, R M
EM: rbernabe@ine.gob.mx
AF: CENICA, PerifＳico 5000, Mexico, DF 04530 Mexico
AU: Marquez, C
EM: cmarquez@ine.gob.mx
AF: CENICA, PerifＳico 5000, Mexico, DF 04530 Mexico
AU: Gaffney, J S
EM: Gaffney@anl.gov
AF: Argonne National Laboratory, Bldg. 203/ER, Argonne, IL 60439 United States
AU: Marley, N
EM: marley@anl.gov
AF: Argonne National Laboratory, Bldg. 203/ER, Argonne, IL 60439 United States
AU: Volkamer, R
EM: rainer@MIT.EDU
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Zuberi, B
EM: bzuberi@geo2tech.com
AF: Massachusetts Institute of Technology, 77 Massachusetts Av., Cambridge, MA 02139 United States
AU: Brune, W
EM: brune@essc.psu.edu
AF: Pennsylvania State University, 503 Walker Bldg., University Park, PA 16802 United States
AU: Lesher, R
EM: blesher@psu.edu
AF: Pennsylvania State University, 503 Walker Bldg., University Park, PA 16802 United States
AU: Shirley, T
EM: trs161@psu.edu
AF: Pennsylvania State University, 503 Walker Bldg., University Park, PA 16802 United States
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: University of Colorado-Boulder, UCB 216, Boulder, CO 80309 United States
AB: An Aerodyne Aerosol Mass Spectrometer (AMS) was deployed at the CENICA Supersite during the Mexico City Metropolitan Area (MCMA-2003) field study from March 29 to May 4, 2003. The AMS provides real time information on mass concentration, and composition of the particulate matter (PM) with high time and size resolution. A beam width probe was used to evaluate whether particles were lost due to excessive broadening of the particle beam. Results show that the shape-related particle collection efficiency was approximately 1 during the campaign. The organic fraction of the PM represents two thirds of the mass, while the rest consists of inorganic compounds. The aerosol was neutralized most of the time; however during the periods with the highest sulfate concentration, the aerosol was acidic. All of the species measured with the AMS have diurnal cycles which can be qualitatively interpreted as the interplay of direct emissions; photochemical production in the atmosphere followed by condensation; gas-to-particle partitioning; boundary layer dynamics; and horizontal advection. The species size distributions were found to be mainly bimodal. The smaller mode is dominated by traffic emission particles, and the accumulation mode contains mainly secondary inorganic and organic compounds. We present the size distribution evolution during one day of the campaign as a case study for the formation and transformation of the PM in Mexico City. We compare the AMS results with measurements done using an Optical Particle Counter (LASAIR), an aerosol photometer, and an R&P PM2.5 TEOM that were also deployed during the MCMA-2003 campaign. Finally we compare our data with those from previous campaigns in Mexico City.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0317 Chemical kinetic and photochemical properties
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting