1. How Does the Sample Affect the Measurement of Different Carbon Fractions? Judith C. Chow Desert Research Institute Reno, NV presented at the International Workshop for the Development of Research Strategies for the Sampling and Analysis of Organic and Elemental Carbon Fractions in Atmospheric Aerosols Durango, Colorado March 4, 2003

2. Types of Sample Effects Filter samples Carbon particle composition Chemical and physical interactions between carbon and other constituents

3. Filter Sample Biases Non-uniform filter deposit biases scaling from punch to whole filter Non-uniform filter punch deposit biases optical monitoring and charring Too light or too dark particle deposits make pyrolysis correction uncertain More heavily loaded samples require longer combustion time at each temperature step Organic vapor adsorption and volatilization in filter biases OC and pyrolysis correction

4. Non-Uniform Sample Deposits (Chow, 1995)

5. Carbon Particle Composition Ambient mixtures, source mixtures, and pure carbon substances do not respond to heating in the same way Thermal evolution protocols are poorly documented and characterized Thermal evolution temperatures are not optimized to bracket compositions Carbonates are not present in most ambient PM 2.5 samples, and CaCO 3 evolves at >800 °C if they are present Samples do not respond the same as calibration standards

6. At Least 15 International Thermal Combustion Carbon Methods Oregon Graduate Institute thermal optical reflectance (TOR)(Huntzicker et al., 1982) IMPROVE TOR and thermal optical transmittance (TOT) (Chow et al., 1993, 2001) NIOSH TOT (NIOSH, 1999) ACE-Asia TOT(Mader et al., 2001) Hong Kong University of Science and Technology UST-3 TOT (Yang and Yu, 2002)

7. At Least 15 International Thermal Combustion Carbon Methods (continued) Meteorological Service of Canada MSC1 TOT(Sharma et al., 2002) U.S. Speciation Trends Network (STN) TOT General Motors Research Laboratory two temperature (Cadle et al., 1980) Brookhaven National Laboratory two temperature (Tanner et al., 1982) Japanese two temperature (Mizohata and Ito, 1985)

8. At Least 15 International Thermal Combustion Carbon Methods (continued) Two-temperature thermal manganese oxidation(Fung, 1990) R&P two temperature (Rupprecht et al., 1995) French two-temperature pure oxygen combustion(Cachier, 1989a, 1989b) Lawrence Berkeley Laboratory continuous temperature ramp (Novakov, 1982) German VDI extraction/combustion (Verein Deutcher Ingenieure, 1999)

9. Differences among Operating Parameters Combustion atmospheres Temperature ramping rates Temperature plateaus Residence time at each plateau Optical monitoring configuration and wavelength Standardization Sample aliquot and size Oxidation (C to CO 2 ) catalyst Evolved carbon detection method Carrier gas flow through or across the sample Location of the temperature monitor relative to the sample

10. Laboratory intercomparisons are not consistent (Schmid et al., 2001) 11TOT10TOT 11bTOT 12TOT 11TOT10TOT 11bTOT 13TOR

11. Same method intercomparisons show differences (Schauer et al., 2003)

12. Comparison of EC Concentrations between TMO and TOR Methods (Fung et al., 2002)

13. IMPROVE carbon thermogram STN carbon thermogram Sample from Hong Kong urban site on 04/17/01 with 9.9 ± 0.8 ug/m 3 OC and 7.8 ± 0.8 ug/m 3 EC

14. Carbon Source Profiles (Watson et al., 1994) Diesel-fueled vehiclesGasoline-fueled vehicles

15. Hong Kong Vehicle Exhaust Profiles (Cao et al., 2003) Source Differences in Carbon Fractions

16. BRAVO Source Profiles (Chow et al., 2003) Source Differences in Carbon Fractions

17. No relationship between EC and carbonate by acidification (Chow and Watson, 2002) IMPROVE samples and IMPROVE protocol

18. Carbon Standards Should be Similar to Samples Water-soluble organics (e.g., sucrose, KHP, organic acids) Carbon dioxide and methane Nebulized charcoal resuspension Carbon blacks Graphite powders Organic dyes (e.g., nigrosin, C 48 N 9 H 51 ) Carbon arc emissions Simulated source emissions Neutral density filters

19. Some Organic Compounds Absorb Light (Justus et al., 1993) Transmission through nigrosin (C 48 N 9 H 51 ) dye

20. Chemical Composition of Carbon Black and Fresh Soot (Watson and Valberg, 2001)

21. Chemical and Physical Interactions of Carbon with Other Constituents Oxidation interactions Catalytic reactions Optical interactions

22. Increasing rate of graphite oxidation by MnO 2 (Fung, 1990) 1000 °K 900 °K 833 °K 800 °K

23. Catalytic reactions with glass-fiber filter (525 °C) (Lin and Friedlander, 1988a, 1988b, 1988c) Na, K, Pb, Mn, Fe, Ca, V, Cu, Ni, Co, and Cr compounds are known catalysts

24. Carbon Fractions are Probably Different for Different Applications Visibility and radiation balance –Visible light absorption and scattering by particles in the atmosphere Source attribution –Consistently define fractions in source and receptor samples Health effects –Absorption of toxic substances on EC Chemical and physical models –Reaction surfaces, catalytic properties

25. Research Needs Critically summarize and review non- atmospheric carbon literature Document methods (combustion temperatures, ramping rates, residence times, optical pyrolysis corrections) Prepare different standards representing different black carbon sources Perform optical modeling to verify changes in absorption and scattering properties

26. Research Needs (continued) Optimize carbon fractions for source identification Quantify effects of pyrolysis on and within a filter to resolve reflectance/transmittance differences Quantify effects of non-absorbing particles, optical monitoring wavelengths, initial darkness, carbonate deposits, and oxygen- supplying minerals Calibrate reflectance and transmittance measurements and report with carbon fractions at beginning, minimum, oxygen introduction, and end of analysis

27. References Cachier, H.; Bremond, M.P.; and Buat-Ménard, P. (1989a). Thermal separation of soot carbon. Aerosol Sci. Technol., 10(2):358-364. Cachier, H.; Bremond, M.P.; and Buat-Ménard, P. (1989b). Determination of atmospheric soot carbon with a simple thermal method. Tellus, 41B(3):379-390. Cadle, S.H.; Groblicki, P.J.; and Stroup, D.P. (1980). An automated carbon analyzer for particulate samples. Anal. Chem., 52(13):2201-2206. Cao, J.J.; Ho, K.F.; Lee, S.C.; Fung, K.; Zhang, X.Y.; Chow, J.C.; and Watson, J.G. (2003). Characterization of roadside fine particulate carbon and its 8 fractions in Hong Kong. Sci. Total Environ., submitted. Chow, J.C.; Watson, J.G.; Pritchett, L.C.; Pierson, W.R.; Frazier, C.A.; and Purcell, R.G. (1993). The DRI Thermal/Optical Reflectance carbon analysis system: Description, evaluation and applications in U.S. air quality studies. Atmos. Environ., 27A(8):1185-1201.

28. References (continued) Chow,J.C. (1995). Summary of the 1995 A&WMA critical review: Measurement methods to determine compliance with ambient air quality standards for suspended particles. EM 1, 12-15. Chow, J.C.; Watson, J.G.; Crow, D.; Lowenthal, D.H.; and Merrifield, T. (2001). Comparison of IMPROVE and NIOSH carbon measurements. Aerosol Sci. Technol., 34(1):23-34. Chow, J.C.; and Watson, J.G. (2002). PM 2.5 carbonate concentrations at regionally representative Interagency Monitoring of Protected Visual Environment sites. J. Geophys. Res., 107(D21):ICC 6-1-ICC 6-9. doi: 10.1029/2001JD000574. Chow, J.C.; Watson, J.G.; Kuhns, H.D.; Etyemezian, V.; Lowenthal, D.H.; Crow, D.J.; Kohl, S.D.; Engelbrecht, J.P.; and Green, M.C. (2003). Source profiles for industrial, mobile, and area sources in the Big Bend Regional Aerosol Visibility and Observational (BRAVO) Study. Chemosphere, submitted. Fung, K.K. (1990). Particulate carbon speciation by MnO 2 oxidation. Aerosol Sci. Technol., 12(1):122-127. Fung, K.K.; Chow, J.C.; and Watson, J.G. (2002). Evaluation of OC/EC speciation by thermal manganese dioxide oxidation and the IMPROVE method. J. Air & Waste Manage. Assoc., 52(11):1333-1341.

29. References (continued) Huntzicker, J.J.; Johnson, R.L.; Shah, J.J.; and Cary, R.A. (1982). Analysis of organic and elemental carbon in ambient aerosols by a thermal- optical method. In Particulate Carbon: Atmospheric Life Cycle, G.T. Wolff and R.L. Klimisch, Eds. Plenum Press, New York, NY, pp. 79-88. Justus, B.L.; Huston, A.L.; and Campillo, A.J. (1993). Broadband thermal optical limiter. Appl. Phys. Lett., 63(11):1483-1485. Lin, C.; and Friedlander, S.K. (1988a). Soot oxidation in fibrous filters. 1. Deposit structure and reaction mechanisms. Langmuir, 4(4):891-898. Lin, C.; and Friedlander, S.K. (1988b). Soot oxidation in fibrous filters. 2. Effects of temperature, oxygen partial pressure, and sodium additives. Langmuir, 4(4):898-903. Lin, C.I.; and Friedlander, S.K. (1988c). A note on the use of glass fiber filters in the thermal analysis of carbon containing aerosols. Atmos. Environ., 22(3):605-607.

30. References (continued) Mader, B.T.; Flagan, R.C.; and Seinfield, J.H. (2001). Sampling atmospheric carbonaceous aerosols using a particle trap impactor/denuder sampler. Environ. Sci. Technol., 35(24), 4857- 4867. Mizohata, A.; and Ito, N. (1985). Analysis of organic and elemental carbon in atmospheric aerosols by thermal method. Annual Report of the Radiation Center of Osaka Prefecture, 26(0):51-55. NIOSH (1999). Method 5040 Issue 3 (Interim): Elemental carbon (diesel exhaust). In NIOSH Manual of Analytical Methods, 4th ed. National Institute of Occupational Safety and Health, Cincinnati, OH. Novakov, T. (1982). Soot in the atmosphere. In Particulate Carbon: Atmospheric Life Cycle, G.T. Wolff and R.L. Klimisch, Eds. Plenum Press, New York, NY, pp. 19-41.

31. References (continued) Rupprecht, E.G.; Patashnick, H.; Beeson, D.E.; Green, R.E.; and Meyer, M.B. (1995). A new automated monitor for the measurement of particulate carbon in the atmosphere. In Proceedings, Particulate Matter: Health and Regulatory Issues, J.A. Cooper and L.D. Grant, Eds. Air and Waste Management Association, Pittsburgh, PA, pp. 262- 267. Schmid, H.P.; Laskus, L.; Abraham, H.J.; Baltensperger, U.; Lavanchy, V.M.H.; Bizjak, M.; Burba, P.; Cachier, H.; Crow, D.J.; Chow, J.C.; Gnauk, T.; Even, A.; ten Brink, H.M.; Giesen, K.P.; Hitzenberger, R.; Hueglin, C.; Maenhaut, W.; Pio, C.A.; Puttock, J.; Putaud, J.P.; Toom- Sauntry, D.; and Puxbaum, H. (2001). Results of the "Carbon Conference" international aerosol carbon round robin test: Stage 1. Atmos. Environ., 35(12):2111-2121. Sharma, S.; Brook, J.; Cachier, H.; Chow, J.C.; Gaudenzi, A.; and Lu, G. (2002). Light absorption and thermal measurements of black carbon in different regions of Canada. J. Geophys. Res., 107(D24):AAC 11-1- AAC 11-11. doi:10.1029/2002JD002496.

32. References (continued) Tanner, R.L.; Gaffney, J.S.; and Phillips, M.F. (1982). Determination of organic and elemental carbon in atmospheric aerosol samples by thermal evolution. Anal. Chem., 54(9):1627-1630. Verein Deutcher Ingenieure (1999). Method 2465 Part 2: Measurement of soot (ambient air)-Thermographic determination of elemental carbon after thermal desorption of organic carbon. Prepared by Verein Deutcher Ingenieure, Beuth, Berlin, FRG. Watson, A.Y.; and Valberg, P.A. (2001). Carbon black and soot: Two different substances. Am. Industrial Hygiene Assoc. J., 62(Mar/Apr):218-228. Watson, J.G.; Chow, J.C.; Lowenthal, D.H.; Pritchett, L.C.; Frazier, C.A.; Neuroth, G.R.; and Robbins, R. (1994). Differences in the carbon composition of source profiles for diesel- and gasoline-powered vehicles. Atmos. Environ., 28(15):2493-2505. Yang, H.; and Yu, J.Z. (2002). Uncertainties in charring correction in the analysis of elemental and organic carbon in atmospheric particles by thermal/optical methods. Environ. Sci. Technol., 36(23):5199-5204.