OC/EC Workshop

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An International Workshop
for the
Development of Research Strategies for the Sampling and Analysis of Organic and Elemental Carbon Fractions in Atmospheric Aerosols

March 3-5, 2003
Durango, Colorado USA

Hosted by:
· Community Services, Fort Lewis College (host and coordination)
· Desert Research Institute (facilitator)

Made possible with funding and support from:
· National Science Foundation
· EPA Office of Air Quality Planning & Standards
· EPA National Exposure Research Laboratory
· Environmental Protection Agency, Region 8
· National Park Service Intermountain Region
· Western Regional Air Partnership

Statement of Problem—Elemental carbon, sometimes termed “black carbon” or “soot,” is an important component of suspended particles; however while methods that measure total carbon usually provide equivalent values, those that measure the EC portion of the total are widely variable. Since the EC is subtracted from the total to obtain organic carbon, OC is equivalently different. Periodic interlaboratory comparisons that have been conducted reveal differences, but they do little to understand and resolve the causes of discrepancies. A more fundamental approach is needed to understand the reasons why these discrepancies exist and how EC should be quantified for different purposes.



9 a.m. -
4 p.m.

— Exclusively for lead presenters, facilitators, and scribes to discuss topics, prepare for presentations, and begin outlining and formatting workshop outcomes into a Research Strategy —
6:30 p.m. Registration Begins
7:00 p.m. Reception
7:45 p.m. Welcome by Dr. Stephen Roderick, Vice President of Academic Affairs, Ft. Lewis College (Introduced by Tim Richard)
7:50 p.m. Workshop Overview, background, context, purpose & process— Dr. John Watson, DRI
8:00 p.m.

Keynote Speaker: John Bachmann (Science Director, EPA OAQPS)
“The importance of measurements of particulate carbon and organic particle fractions for regulation and environmental assessment on a local, regional, and global scale. Unifying PM health/NAAQS, visibility/haze, and regional/global climate themes.”

8:30 p.m. ADJOURN
7:30 Registration Continues
8:00 WELCOME by John Ninnemann, Dean of Arts and Sciences, Fort Lewis College
~Questions & Floor Discussions~

I. What is elemental carbon and how do definitions differ for different applications? What are the OC and EC properties that are of importance to human health, visibility, climate, and source attribution? To what extent can a single analytical method or protocol meet these different needs?

TOPIC LEADER: Robert Cary, President, Sunset Laboratory


II. What options exist for fundamental and traceable OC and EC standards? What standards have been used in the past? How well do these represent properties of user communities? What other standards might be added? How can these be created, maintained, and disseminated?

TOPIC LEADER: Lloyd Currie, Emeritus Fellow, National Inst. of Standards & Technology

Follow Up Presentation—"On the Distribution of the Blank." L.A. Currie and J.M. Conny (NIST)

10:15 Brief Break

III. How does the sample affect the measurement of different carbon fractions? How do properties of particles on a filter differ from those in ambient air? How do different compounds react with heat and among themselves to create pyrolized carbon? How do different filter loadings affect optical measures of pyrolysis? Under what conditions might other carbon-containing components (e.g., carbonates) be detected as OC or EC? What additional information should be reported with OC and EC values to evaluate the precision and validity of an OC/EC split?

TOPIC LEADER: Judith Chow, Desert Research Institute

Follow Up Presentation 1—"Effects of iron oxides on the determination of organic and elemental carbon using thermal optical techniques." Kochy Fung, AtmAA, Calabasas, CA

Follow Up Presentation 2— “Measurement of Carbonate Minerals in Aerosol Samples.” Johann Engelbrecht, Desert Research Institute, Reno, Nevada

11:30 Poster Viewing Time

LUNCH and Poster Viewing


IV. What are the important parameters that need to be defined for a carbonaceous aerosol analysis and how should these be documented for different analysis protocols? How do temperature plateaus, analysis times, combustion atmospheres, heating rates, and optical pyrolysis monitoring affect the definition of carbon fractions? What differences in analysis protocols should be reported with OC and EC concentrations?

TOPIC LEADER: Hélène Cachier, LSCE/CFR, laboratoire mixte CEA-CNRS, France


V. What specific compounds are likely to evolve during different temperature fractions of thermal evolution methods used to analyze carbonaceous aerosols? To what extent do similar compounds evaporate within definable temperature groupings? How well do current temperature-defined fractions defined useful groupings? How might temperature fractions or the detection of thermally-evolved products be optimized for applications such as source attribution?

TOPIC LEADER: Joellen Lewtas, Senior Research Scientist, US EPA/Office of Research & Dev’t/Nat’l Exposure Research Lab

Follow Up Presentation 1—"Organic Carbon Concentration and Composition in Fine Particulate Matter Collected During ARIES Study." Barbara Zielinska, Desert Research Institute, Reno, Nevada

Follow Up Presentation 2—"Insights from Thermal Analysis of Individual Organic Compounds, Mixtures, Black Carbon Surrogates, Airborne Particulate Matter and
Extracts." L. A. Gundel, Environmental Energy Technologies Division, Lawrence Berkeley National Lab


VI. How does carbonaceous particle composition, shape, and size affect optical properties in the air and when sampled on a filter? How might optical properties of particles in the air differ from those collected on a filter? How might filter transmittance and reflectance change during heating as particle morphology and composition change? Why might optical transmission and reflectance give different pyrolysis corrections?

TOPIC LEADER: Kirk Fuller, Research Scientist, National Space Science and Technology Center, Univ. of Alabama

4:00 Brief Break

VII. How might current analysis methods be enhanced or combined to obtain more information about the nature of OC, EC, and other carbon fractions in filter samples? What can be done with existing analysis methods and samples? What might be provided by collocated measurements? What hardware and software changes would permit more of the commonly applied protocols to be applied with the same analytical instruments?

TOPIC LEADER: Hans Hansson, Air Pollution Laboratory, Institute of Applied Environmental Research and Department of Meteorology, Stockholm University, Sweden


VIII. What new and innovative sampling, analytical, and interpretive techniques are needed to determine the properties and sources of carbonaceous aerosol in the atmosphere? What is the role of in situ and laboratory analysis now and in the future? How can multiple measurements in space and time assist in the interpretation of and validation of OC/EC fractions? How might new technologies satisfy the needs of multiple users? How might they better quantify OC and EC sources for emissions reduction strategies?

TOPIC LEADER: Hans Moosmüller, Research Professor, Desert Research Institute

Follow Up Presentation"Source Apportionment Using Semi-Continuous Measurement of OC, EC, and Other Markers of Combustion Emissions." Delbert J. Eatough, Brigham Young University, Provo, Utah

6:15 Closing and Poster Viewing
Tuesday Evening Topic Leaders and Breakout Group Leaders meet to design Breakout Group Interaction, Identify Specific Outcomes, Compose Questions to be Addressed. Continue early morning Wed. if necessary.
8:30 KEYNOTE — Dr. Bruce Doddridge, National Science Foundation“The importance of OC and EC for health, climate and visibility from the point of view of the NSF”

Updates of Current Projects (Strictly limited to five minutes each)

1. Sylvia Edgerton, Pacific Northwest National Laboratory: "Coordination of OCEC research between the air quality and climate science community, particularly the possibility that exist through DOE's Atmospheric Radiation Measurement (ARM) Program"

2. Paul Solomon, EPA: “A brief overview of EPA/ORD ambient PM methods research program.”

3. Peter Hyde, Arizona Dept. of Environmental Quality: "OC/EC Considerations in Phoenix and Downwind Class I Areas"

4. Philip Hopke, Clarkson University: "Continuous Characterization of Carbon in Fine Particulate Matter"5. Antony Chen, DRI: "Measuring Elemental Carbon Absorption Using a Dual Thermal Optical Reflectance/Transmittance Analyzer"

5. Antony Chen, DRI: "Measuring elemental carbon absorption using a dual thermal optical reflectance/transmittance analyzer."

6. Jianzhen Yu, Hong Kong University: “Charring Minimization in Thermal Analysis of Aerosol Carbon” & “Uncertainties in Optical Charring Correction Schemes.”

7. William Malm, Natl Park Service/CIRA: "Implications of using OC/EC to estimate fire and SOA contributions to carbonaceous material"

8. Rich Scheffe, EPA: "Reconciling Carbon Measurements Between the EPA Speciation Trends and IMPROVE Networks."

9. John Watson: "Secondary Organic Aerosol Research Strategy Update"

10. Joellen Lewtas/Barbara Zielinska announce the next workshop on —“Organic Speciation”

10:00 Focus Group Sessions (John Watson will describe structure & selection process)
1:30 Breakout Group Reports
2:30 Brainstorming Consensus Session
Thursday & Friday, March 6-7, 2003 ~ (Exclusively for preselected lead presenters, facilitators, sponsors, and scribes to draft of the OCEC Research Strategy.)

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