HR: 17:46h
AN: A24C-08 [Abstracts]
TI: Fast airborne aerosol size and composition measurements from the NCAR C-130 during the MIRAGE-Mex 2006 field campaign
AU: * DeCarlo, P F
EM: decarlop@colorado.edu
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: * DeCarlo, P F
EM: decarlop@colorado.edu
AF: Dept of Atmospheric and Oceanic Science, Univ. of Colorado, 318 UCB, Boulder, CO 80309, United States
AU: Dunlea, E
EM: edward.dunlea@colorado.edu
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Kimmel, J
EM: joel.kimmel@colorado.edu
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Ulbrich, I
EM: Ingrid.Ulbrich@Colorado.EDU
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Ulbrich, I
EM: Ingrid.Ulbrich@Colorado.EDU
AF: Dept. of Chemistry, Univ. of Colorado, 215 UCB, Boulder, CO 80309, United States
AU: Aiken, A
EM: allison.aiken@colorado.edu
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Aiken, A
EM: allison.aiken@colorado.edu
AF: Dept. of Chemistry, Univ. of Colorado, 215 UCB, Boulder, CO 80309, United States
AU: Crounse, J
EM: crounjd@caltech.edu
AF: Geology and Planetary Science, California Inst. of Tech., MC 170-25
1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Wennberg, P
EM: wennberg@gps.caltech.edu
AF: Geology and Planetary Science, California Inst. of Tech., MC 170-25
1200 E. California Blvd., Pasadena, CA 91125, United States
AU: Shinozuka, Y
EM: yohei@hawaii.edu
AF: Department of Oceanography, University of Hawaii, 1000 Pope Rd, Honolulu, HI 96822,
United States
AU: Clarke, T
EM: tclarke@soest.hawaii.edu
AF: Department of Oceanography, University of Hawaii, 1000 Pope Rd, Honolulu, HI 96822,
United States
AU: Zhao, J
EM: jczhou@hawaii.edu
AF: Department of Oceanography, University of Hawaii, 1000 Pope Rd, Honolulu, HI 96822,
United States
AU: Tomlinson, J
EM: jason.tomlinson@tamu.edu
AF: Dept. of Atm. Sci., College of Geosciences, Texas A&M Univ., 3150 TAMU, College Station, TX 77843, United States
AU: Collins, D
EM: dcollins@tamu.edu
AF: Dept. of Atm. Sci., College of Geosciences, Texas A&M Univ., 3150 TAMU, College Station, TX 77843, United States
AU: Campos, T
EM: campos@ucar.edu
AF: NCAR, PO Box 3000, Boulder, CO 80307, United States
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: CIRES, University of Colorado, 216 UCB, Boulder, CO 80309, United States
AU: Jimenez, J L
EM: jose.jimenez@colorado.edu
AF: Dept. of Chemistry, Univ. of Colorado, 215 UCB, Boulder, CO 80309, United States
AB:
A high mass resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, DeCarlo et al., 2006) was
deployed for the first time on an airborne platform during the MIRAGE-Mex campaign on the NCAR C-130
research aircraft, for measurements of size-resolved non-refractory sulfate, nitrate, ammonium, chloride, and
organics. Onboard the C-130 the HR-ToF-AMS was operated in a medium resolution mode known as "V-ToF
mode", providing added chemical resolution of the measured aerosol, while still maintaining good spatial (time)
resolution and allowing the measurement of size distributions. Organic aerosol (OA) accounted for approximately
half of the non-refractory submicron aerosol mass and showed strong correlation with gas phase
measurements of CO and HCN. Due to the strong correlations with HCN and CO, the sources of organic aerosol
are thought to be a combination of biomass burning, transportation and other urban combustion sources, and
(pollution-related) secondary OA (SOA).
High-resolution OA mass spectra were also analyzed with the Positive Matrix Factorization algorithm, including
periods with high and low regional biomass burning (BB) as determined by satellite fire counts and tracers. Four
dominant OA components were extracted. Three oxidized organic aerosol components, termed oxygenated OA 1
and 2 (OOA-1, OOA-2) and biomass burning OA (BBOA) were obtained, along with a reduced "hydrocarbon-like"
(HOA) component. OOA-1 is linked to regional airmasses and highly oxidized and aged organic aerosol. Based
on absolute levels and correlations with tracers in high vs. low fire periods, the majority (total to 2/3) attributed to
anthropogenic sources and up to 1/3 estimated to come from BB during periods of high burning activity. OOA-2
appears to be a fresh SOA strongly correlated with ammonium nitrate, and the Mexico City Basin. The similar
correlation with tracers in both flights strongly indicates an urban origin, and during low fires periods it is the
largest OA component in the Mexico City basin. BBOA is identified as biomass burning aerosol due to a strong
correlation with HCN, and the presence of marker ions such as C2H4O2+ and C3H5O2+ (m/z 60 and 73 markers
for Levoglucosan). At times when burning activity is high, BBOA makes a large contribution to OA mass in the
basin and contributes strongly to the mass in the outflow. This component is small (~10%) during periods of low
BB activity. Comparing to measurements in the city basin (T0, Aiken et al., this conference) the BBOA observed in
the C-130 has increased oxidation. This may be due to SOA formation from BB precursors, or to a Robinson-like
evaporation-oxidation-repartitioning mechanism (Robinson et al., Science, 2007), since fresh BBOA in Mexico is
very volatile (Huffman et al., this conference).
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting