1. Atmospheric Sub-micron Aerosol Organic:  Results from Aerosol Mass Spectrometry
Douglas R. Worsnop, John Jayne, Manjula Canagaratna,
Tim Onasch, Hacene Boudries, Leah Williams
Aerodyne Research, Inc.
Jose Jimenez , Qi Zhang, Peter DeCarlo, Alex Huffman, Alice Delia
University of Colorado
Rami Alfarra, James Allan, Keith Bower, Hugh Coe
UMIST
Ann Middlebrook Jay Slowik, Paul Davidovits
NOAA Boston College
Frank Drewnick, Johannes Schneider Silke Weimer, Ken Demerjian
MPI Mainz SUNY Albany
European Monitoring and Evaluation Program (EMEP)
Workshop on Particulate Matter (PM) Measurement
United Nations Economic Commission for Europe
New Orleans, Wednesday, April 21, 2004

2. Aerodyne Aerosol Mass Spectrometer (AMS)
Particle
Particle Beam
Aerodynamic Sizing
Composition
Generation
Quadrupole
Mass Spectrometer
Chopper
Thermal Vaporization &
Electron Impact Ionization
TOF Region
Aerodynamic Lens
(2 Torr)
Particle Inlet (1 atm)
Turbo Pump
Turbo Pump
Turbo Pump
100% transmission ( nm), aerodynamic sizing, linear mass signal.
Jayne et al., Aerosol Science and Technology 33:1-2(49-70), 2000.
Jimenez et al., Journal of Geophysical Research, 108(D7), 8425, doi: / 2001JD001213, 2003.
The particles enter the AMS and are focused by an aerodynamic lens into a tight beam (<1 mm diameter). In the size range nm we get 100% of the particles transmitted from the inlet to the detector.
The chopper wheel defines the beginning of a time-of-flight period. Smaller particles move faster, so when a packet travels from chopper to detector, the smallest ones arrive first.
The detector consists of a 600 degree C oven that flash vaporizes the particles. The oven is located inside the ionizer region of a quadrupole mass spectrometer. Most of the gas phase molecules are lost in the first chamber of the AMS, so what reaches the ionizer is almost exclusively material that was in the particle phase.
Can use single ion monitoring mode to get quantitative information about single particles, or scan the quadrupole to get complete MS of average particles.

3. AMS: Size Resolved Chemical Composition
of Sub-micron aerosol (PM1)
Non-refractory (NR) composition (thermal vaporization at 600C)
e.g. no black carbon (BC), dust or (typically) seasalt
Electron Impact (EI) Mass Spectrometry – quantitative mass loading
All NR components detected with little uncertainty
direct calibration / chemically unbiased sample
Mass spectrum of inorganics and organics easy to separate
Analysis of organic matter (OM) – primary vs secondary
hydrocarbon (lube oil) vs oxidized (HULIS)
direct measure of OM/OC ratio
Aerodynamic focusing and sizing
collection efficiency  1 for aspherical particles; e.g. (NH4)2SO4
measure CE with beam width probe – particle shape information
aerodynamic (AMS) + mobility (SMPS) sizing
 particle mass, density, shape and fractal dimension + chemistry

4. Mass balance –TEOM, PILS, OC/EC
Organic classification: primary vs oxidized  OM/OC ratio
Sizing – comparison with SMPS ( and Moudi)
small, fractal organic vs mixed organic/sulfate accumulation
dirunal and seasonal patterns
compare to vehicle and dynometer emissions
Future:
ToF-AMS, higher sensitivity (aircraft time response)
and single particle composition
“cheaper, simpler” Q-AMS system
hour time resolution
size binning (<100nm, nm, > 200 nm)

5. Real Time Chemical and Physical Composition of Aerosols
Aerosol Sampling
Sampling frequency - >10Hz
Real-time measurement.
AMS
Nitrate
Sulphate
Ammonium Alkanes
Organics Aromatics
Etc..
Mass distribution
Chemical composition

6. EI Ionization: A + e- ----> A+ ----> ai+
Mass Loading A  (MWA/IEA)  Ion Signal ai
Calibration Factor * (MWNO3/IENO3)
EI Ionization
Cross
Sections

7. Typical ambient aerosol mass spectrum

8. Group Molecule/Species Ion Fragments Mass Fragments
MS Signatures for Aerosol Species Identification
color coded to match spectra
Water H2O H2O+ , HO+ , O+ 18, 17, 16
Ammonium NH3 NH3+, NH2+, NH+ 17, 16, 15
Nitrate HNO HNO3+, NO2+, NO+ 63, 46, 30
Sulfate H2SO H2SO4+, HSO3+, SO3+ 98, 81, 80
SO2+, SO+ 64, 48
Organic CnHmOy H2O+, CO+, CO , 28, 44
(Oxygenated) H3C2O+, HCO2+, Cn’Hm+ 43, 45, ...
Organic CnHm Cn’Hm’+ 27,29,41,43,55,57,69,71...
(hydrocarbon)
Group Molecule/Species Ion Fragments Mass Fragments e-
Standard electron impact 70 eV
Easy to quantify: ca. NIST MS library
Easy to separate inorganic and organic components
Speciation of organic composition is challenging

9. Comparison of PMTACS’01 and PMTACS’04
Time Series,
Diurnal Plots,
and Data Diagnostics
Silke Weimer+, Frank Drewnick‡, Doug Worsnop*, Ken Demerjian+
+ Atmospheric Sciences Research Center, Albany/NY, ‡ MPI for Chemistry, Mainz;
*Aerodyne Res. Inc./Billerica/MA

10. Speciated Mass, Queens, NY
Mass Balance AMS vs.TEOM
Speciated Mass, Queens, NY
The “Other” Category
-PM1 vs PM2.5
-elemental carbon
-crustal oxides
Drewnick et al, 2003
F. Drewnick, J. Schwab, K. Demerjian ASRC SUNY Albany

11. Comparison of FDMS and AMS, PMTACS04 PRELIMINARY
WINTER
AMS/FDMS ~ 0.7
for AMS Particle Collection Efficiency: CE = 0.5
FDMS – Dirk Felton, NYSDEC

12. 10 minute data in PMTACS04 PRLIMINARY ESTIMATED Primary organic
Oxidized organic
Plumes of primary organic are clearly observed
- due to vehicles driving by the site
(frequency increased after college re-opened in
last week of study)
Weimer, Drewnick et al

13. CnHmOy ----> H2O+ CO+ CO2+ C2H3O+
Organic Mass Spectra e-
CnHm ----> Cn’Hm’+
27, 29, 41, 43, 55, 57, 69, 71, ...
C4H9+
CnHmOy ----> H2O+ CO+ CO2+ C2H3O+
27, 29, 55, ….
Following flash vaporization at ~600C

14. Diurnal Cycles of OM Classes
Weimer, Drewnick et al
Summer
57 – primary marker
Winter
44 – oxidized marker

15. Aerosol Size-Resolved Composition with the Aerodyne AMS in Pittsburgh Jose-Luis Jimenez*, Qi Zhang, Manjula Canagaratna, John Jayne, Doug Worsnop, Charles Stanier, Spyros Pandis *Dept. Chemistry & CIRES University of Colorado at Boulder EPA Supersite Meeting Feb. 26, 2004

16. Diesel Vehicle Exhaust
Primary Organic
Component in
Pittsburgh
Zhang, Jimenez et al.
Diesel Vehicle Exhaust
Jayne, Canagaratna et al.

17. Oxidized Organic Component in Pittsburgh Fulvic Acid “HULIS” ????
Zhang, Jimenez et al.
Fulvic Acid
“HULIS” ????
Rami Alfarra et al (UMIST)

18. Total Organics Quantitation vs. Sunset Labs OC
Pittsburgh “Super Site”
OM / OC ~ 1.7
Total Organic = C  (all organic ions)
Qi Zhang, Jose Jimenez, CU

19. FUTURE IDEAS  lower cost
“Cheaper” AMS – smaller, no fast electronics, limited size binning
approaching cost and operational equivalent of RGA or GCMS
simple calibration system?
cost equivalent to collection of individual continuous instruments
add thermal denuder to evaluate semivolatile component
Aerosol Collection (with aerodynamic lens)
(Paul Ziemann) – in situ (EI) mass spectrometric analysis
- separation via volatility
aerosol collection (< 1 hour) [ Hacene Boudries ]
for direct injection into speciation detectors
e.g. GCMS, PTRMS

20. Acknowledgments Support: NSF, ONR, DoE EPA, NASA, NOAA, JARI
Aerodyne
Doug Worsnop
John Jayne
Manjula Canagaratna
Hacene Boudries
Tim Onasch
Phil Mortimer
Leah Williams
Boston College
Jay Slowik
Paul Davidovits
Arizona State
Jonathan Allen
Utah State
Phil Silva
JAPAN
Nobu Tagekawa (Tokyo)
Yutake Kondo (Tokyo)
Akinori Takami (NIES)
Akio Shimono (Sanyu)
Ken-ichi Akiyama (JARI)
Boulder
Jose Jimenez (UC)
Alice Delia, Darren Toohey
Ann Middlebrook (NOAA)
Qi Zhang, Peter Decarlo (UC)
Alex Huffman, Katja Dzepina
Caltech
John Seinfeld, Rick Flagan
Roya Bahreini
Environment Canada
Shao Meng Li, Jeff Brook
Kathy Hayden, Gang Lu,
Richard Leaitch
SUNY Albany
Ken Demerjian
Wyoming
Peter Liu
Derek Montague
PNNL / BNL
Carl Berkowitz, Pete Daum
UMIST
Hugh Coe
Keith Bower
Paul Williams
James Allen
Rami Alfarra
MPI Mainz
Frank Drewnick
Johannes Schneider
Stephan Borrmann
Joachim Curtius
CEH (Edinburgh)
Eiko Nemitz
David Anderson
KFA Juelich
Thomas Mentel
Andreas Wahner
MIT
Xuefeng Zhang
Ken Smith
TOFWERK
Marc Gonin
Katrin Fuhrer
Support: NSF, ONR, DoE
EPA, NASA, NOAA, JARI
Environment Canada