Transcript Holden, A.S., A. P. Sullivan, S. Kreidenweis, J. L. Collett, Jr., B. A. Schichtel, W. C. Malm, and G. Bench. Application of Anion Exchange Chromatography with Pulsed Amperometric Detection for Measurement of Levoglucosan in Ambient Aerosol Samples, Presented at the AAAR Annual Conference, September, 2007 in Reno, NV.

Application of Anion Exchange Chromatography with Pulsed Amperometric Detection
for Measurement of Levoglucosan in Ambient Aerosol Samples
Amanda S. Holden, Amy P. Sullivan, Sonia Kreidenweis, Jeffrey L. Collett, Jr., Colorado State University, Department of Atmospheric Science, Fort Collins, Colorado 80523
Bret Schichtel, William Malm, National Park Service/CIRA, Colorado State University, Fort Collins, Colorado 80523; Graham Bench, Lawrence Livermore National Laboratory, Livermore, California 94551
Results
• Biomass carbon not a big contributor to PM2.5 in
Phoenix
Source Profiles
• 6-day samples taken during winter and summer at 12 IMPROVE sites
• 4 locations analyzed for summer 2005
• 2 remote: Grand Canyon, AZ (HANC) and Rocky Mountain National Park, CO
(ROMO)
• 1 urban: Phoenix, AZ (PHOE)
• 1 “near-urban”: Tonto National Forest, AZ (TONT)
• Samples collected using Hi-vol sampler
• Levoglucosan/TC (total carbon) ratios from source filters
• FLAME study: various fuels burned at the USDA-USFS Fire Science Lab
• Sampled using Hi-vol samplers with 2.5μm size cut
• Split into geographical regions: Southwest and North/Central U.S.
• Within regions, split into fuel types
• Compared individual fuel types to all fuel types for each region
• Regional average ratio applied to IMPROVE samples
0.032
Levoglucosan/TC (ugC/ugC)
0.028
Tree
Complexes
0.024
Duff
Needles/
Branches
0.02
0.016
Leaves
0.012
0.008
3
• Significant fossil carbon in Tonto National Forest as
well
• Possible transport from Phoenix
• Rocky Mountain shows highest biomass burning
influence
• Some weeks show biomass carbon concentrations
higher than total carbon
• Possibly due to sampling error- biomass carbon
calculated from different data than fossil +
contemporary carbon
• Source profile used possibly not appropriate for
this site
Contemporary Carbon
Biomass Carbon
7/6
7/12
7/20
7/27
8/3
8/10
8/17
8/24 Average
6/29
• Some smoke plumes too small to be seen by satellite
• Possible false negatives
• For the most part, smoke plume presence
corresponded with higher biomass carbon
contributions
• These calculations only include primary aerosol
contributions
7/6
7/13
7/6
7/13
Fossil Carbon
7/20
7/27
8/3
Start Date of Sampling
7/20
7/27
8/3
8/10
8/17
Average
ROMO Site: Rocky Mountain Nat'l Park, CO
Biomass Carbon
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
6/29
Biomass Carbon
Start Date of Sampling
HANC Site: Grand Canyon, AZ
Contemporary Carbon
Fossil Carbon
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
Start Date of Sampling
• Smoke plume images did not show all biomass
contributions
• Do not include secondary organic aerosol (SOA)
contributions from reactions within aged smoke plumes
• Additional “smoke SOA” might contribute to additional
contemporary carbon not attributed to primary biomass
burning aerosol using this method
Fossil Carbon
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
6/22
Carbon concentration (ugC/m3)
Figure 1. Organic carbon shown as % PM2.5
mass according to IMPROVE measurements.
Methods
Ambient Sampling
Carbon concentration (ugC/m )
• Mid- to high-contributions of biomass carbon in
Grand Canyon and Tonto National Forest
• Goal: to estimate biomass burning contributions to PM2.5 concentrations in several locations
• Because these samples are from the summer, we can assume that biomass burning is primarily from prescribed
fires, rather than residential wood combustion (e.g. fires in fireplaces)
• Most literature source profiles are from residential wood combustion
Contemporary Carbon
• Urban site: high fossil carbon
• This study uses a new method to measure levoglucosan in ambient samples
TONT Site: Tonto National Forest, AZ
PHOE Site: Phoenix, AZ
Carbon concentration (ugC/m3)
• Fire is an important contributor to regional haze and elevated concentrations of particulate matter,
especially in the western U.S.
• Levoglucosan used as a tracer for biomass burning
Contemporary Carbon
Carbon concentration (ugC/m3)
Background
8/10
8/17
Average
Fossil Carbon
Biomass Carbon
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
6/28
7/5
7/12
7/19
7/26
8/2
8/9
8/16
Average
Start Date of Sampling
Figure 7. Contemporary, fossil, and biomass carbon concentrations (as TC), given for each sampling period and as an overall
average for each site. Contemporary and fossil carbon are stacked to show the total carbon concentration for that sample.
0.004
0
Figure 3. Levoglucosan to TC ratios for FLAME fuels used in
calculating source profiles. Fuels are separated into different
compositions. Striped bars are Southwestern fuels, while solid
bars are North/Central fuels.
Figure 2. Map showing locations of IMPROVE sampling
sites and the origin of FLAME fuels used as source
profiles. Table inset gives fuel name and composition.
• Back trajectories
• From HYSPLIT (HYbrid Single-Particle Lagrangian Integrated
Trajectory) On-line Transport and Dispersion Model
• NOAA and Australia’s Bureau of Meteorology
• Gives advection of a single particle using meteorological data
• Examined 48-hour back trajectories ending each sampling day
• Region where air parcels originated used in determining which
source profile region to use
• Looking at back trajectories with smoke/fire images gives
an estimate of which samples should be influenced by
biomass burning
Figure 4. Images for the ROMO site, 8/16/2005-8/23/2005. (below left) Image from HYSPLIT. Black star
indicates location of IMPROVE sampling site. Colored lines indicate 48-hour back trajectories, corresponding
to the time periods shown on the table below the image. (below right) Image from Satellite Fire Detections
map. Red circle indicates location of IMPROVE sampling site. Grey areas indicate analyzed smoke plumes,
boxes indicate locations of fires (different colored boxes corresponding to different satellite sources).
• Levoglucosan and other sugars measured using High-Performance Anion Exchange
Chromatography with Pulsed Amperometric Detection, with a Dionex CarboPac
column (PA10) and a gradient of H2O/NaOH eluent
• Organic carbon (OC) and elemental carbon (EC) measured using a Sunset Labs
carbon analyzer
• TC = OC + EC
• All concentrations were blank corrected
• Estimation of biomass combustion contributions
Response (nC)
Biomass carbon (μgC/m3) =
200
mannosan
150
100
galactosan
a
50
0
0
1
2
3
4
5
6
7
8
Response time (min)
9
10 11 12
• The two “mystery” peaks (“a” and “b”) in our chromatogram appear to
contain extra information about fuel type (Figure 8)
• Each fuel type dominated by peak “b”
• Branches show the highest dominance of peak “b”
• Different fuel types (grasses, branches, needles, leaves) yield
chromatograms with various ratios of the sizes of the two mystery peaks
• Ambient IMPROVE site data fall along certain fuel type lines
• PHOE and TONT peak ratios agree with grass ratios
• HANC peak ratios are similar with leaf ratios
• ROMO peak ratios look like grass or branch ratios
• Grasses: easterly winds
• Branches: westerly winds
1:1
140
y = 0.25x + 7.06
R2 = 0.88
120
y = 0.10x + 15.92
R2 = 0.67
100
80
60
40
50
100
150
200
250
300
350
Response for peak "b" (nC)
Figure 5. HPAEC-PAD setup
used for analyzing sugars in
FLAME and IMPROVE filters.
b
Leaves
ROMO
Linear (Branches)
y = 0.30x + 11.13
2
R = 0.96
160
0
• Analyzing concentrations for FLAME and IMPROVE filters
levoglucosan
Needles
HANC
Linear (Leaves)
0
Sample Analysis and Calculations
250
180
Branches
TONT
Linear (Needles)
Linear (Series9)
20
• Smoke/fire images
• From NOAA NGDC (National Geophysical Data Center)
Satellite Fire Detections map
• Smoke plumes and fire locations from HMS (Hazard Mapping
System) Fire and Smoke Product
• HMS uses images from GOES, AVHRR, and MODIS satellites
200
Response for peak "a" (nC)
Smoke/Fire Presence
Grasses
PHOE
Series9
Linear (Grasses)
y = 0.47x + 12.89
2
R = 0.93
Figure 6. Sample
carbohydrate
chromatogram for a
FLAME burn of longleaf
pine needles. Peaks
corresponding to known
sugars are labeled. Two
“mystery” peaks regularly
appear; these are denoted
“a” and “b” (retention times
3.24 and 3.65 minutes,
respectively).
Figure 8. Response at mystery peaks “a” and “b”, split into fuel type and IMPROVE
sampling site. Linear trendlines, and their corresponding equations and R2 values, are
shown for each fuel type.
Conclusions and Future Work
• HPAEC-PAD provides a simple, cost-effective analytical method for looking at smoke markers in ambient aerosol samples
• Estimates of biomass combustion contributions to ambient aerosol carbon are mostly consistent with 14C contemporary/fossil splits: few instances
of over-prediction (ROMO site)
• It is important to use wild fire source profiles for this type of analysis, as they are very different from residential wood combustion source profiles
• Will look soon at additional IMPROVE sites as well as winter samples
• “Mystery” peaks in HPAEC-PAD chromatograms could be useful as additional biomass burning source markers, especially for providing more
information about types of fuels combusted
• For more about FLAME source profiles, see Amy Sullivan’s platform presentation, 3:50 p.m. Tuesday, #5B.1
levosample
(levo / TC ) source
• Compared biomass combustion carbon to fossil and contemporary carbon
• Fossil and contemporary carbon concentrations calculated from carbon isotope
measurements using accelerated mass spectrometry at the Lawrence Livermore
National Laboratory
• Contemporary carbon: biomass burning, biogenic emissions
• Different from modern carbon, which includes inputs from atomic bomb testing
• Fossil carbon: fossil fuel combustion
Acknowledgements
Funding: Joint Fire Science Program and the National Park Service
Sample collection: Chuck McDade and the IMPROVE team at U.C.
Davis
Support during FLAME: Cyle Wold, Wei Min Hao, and the Fire
Science Lab staff
References
• Bench, G., P. Herckes, 2004. Measurement of Contemporary and Fossil Carbon Contents of PM2.5 Aerosols: Results from
Turtleback Dome, Yosemite National Park. Environ. Sci. Technol. 38: 2424-2427.
• Engling, G., C.M. Carrico, S.M. Kreidenweis, J.L. Collett, Jr., D.E. Day, W.C. Malm, E. Lincoln, W.M. Hao, Y. Iinuma, H.
Herrmann, 2007. Determination of Levoglucosan in Biomass Combustion Aerosol by High Performance Anion Exchange
Chromatography with Pulsed Amperometric Detection. Atmos. Env., in review.
• Gorin, C.A., J.L. Collett, Jr., P. Herckes, 2006. Wood Smoke Contribution to Winter Aerosol in Fresno, CA. J. Air & Waste
Manage. Assoc. 56: 1584-1590.
• Schichtel, B., W. Malm, G. Bench, S. Fallon, C. McDade, J. Chow, 2007. Fossil and Contemporary Fine Carbon Fractions at
12 Rural and Urban Sites in the United States, J. Geophys. Res., in review.