BNL Home

Arthur J. Sedlacek


Dr. Arthur J. Sedlacek is an atmospheric chemist within the Environmental & Climate Sciences Department where he also serves at technical manager for the Aerosol Direct Effects group. He received his Ph.D. in physical chemistry from the University of Utah where his thesis research focused on the use of infrared and Raman spectroscopies to follow reaction dynamics in both amorphous solids and in the gas phase. His post-doctoral research centered on understanding the complex energy transfer mechanisms and reaction dynamics associated with highly-vibrationally excited molecules. After joining the BNL scientific staff in 1992, he helped establish the first-ever remote sensing program at BNL and in 1999, Dr. Sedlacek’s group designed the first ever Raman lidar system specifically for the short-range, in situ, non-contact detection and identification of ground contamination. This groundbreaking work, developed to support civilian First Responders and Haz/Mat professionals, was awarded a patent in 2003.

Since joining the Environmental & Climate Sciences Department in 2004, Dr. Sedlacek’s research has focused on elucidating the contribution black carbon has to aerosol direct radiative forcing. This work resulted in the development of a new instrument, based on photothermal interferometry, for the in situ measurement of black carbon. More recently, he has expanded his research interests to examine how atmospheric aging affects both the optical and microphysica properties of black carbon. Dr. Sedlacek has organized several symposia on the application of lidar and vibrational spectroscopy for chemical and biological sensing. He has presented the results of his research at numerous national and international forums, through invited talks and in peer-reviewed publications.


  • University of Utah, Ph.D., Chemical Dynamics
    Dissertation topic: "Photochemistry of Amorphous Solids"
  •  University of Wyoming, Laramie, B.S., Chemistry


  • U.S. Patent 6,606,677: Mini-Raman Sensor for the Remote, Standoff Sensing of Chemical/Biological Substances and Method for Sensing Same, Ray, Mark D., and Arthur J. Sedlacek, III,  granted 6/22/04


  • DOE Certificate of Appreciation 1998
  • Distinguished BNL Research and Development Award – 1998

Areas of Interest

  • Understanding the atmospheric aging on the optical and microphysical properties of soot and related aerosols
  • Development of model aerosol systems to elucidate the effects of encapsulation on aerosol optical properties
  • Aerosol radiative forcing and how it relates to global climate change
  • Development of novel optical-based instrumentation for aerosol, chemical and biological species detection
  • Measurement of fundamental spectroscopic properties


  • American Chemical Society (ACS)
  • Optical Society of America, (OSA)
  • American Geophysical Union (AGU)
  • American Association for Aerosol Research (AAAR)


  • Research Chemist, Brookhaven National Laboratory; Jan 1992 - present
  • Postdoctoral Research Associate, Brookhaven National Laboratory; Jan 1989-Sept 1992

External Service

  • Session chairs for AGU and AAAR conferences
  • Organized symposia on the application of optical sensors for Homeland Security for the International Society for Optical Engineering (1996, 1997, 1999, 2001, 2001, 2002, 2003, 2004, 2005) as well as serving on the Executive Program committee (2001, 2003, and 2004)
  • Guest Editor: IEEE Sensors Journal; Special Issue on Sensors for the Prevention of Terrorists Acts (2004)
  • Participation in Department of Energy/National Security and Nonproliferation Congressional Hill EXPO (1998 and 1999)

Publications (since 2003)

Adachi, K., Oshima, N., Gong, Z., de Sá, S., Bateman, A. P., Martin, S. T., de Brito, J. F., Artaxo, P., Cirino, G. G., Sedlacek Iii, A. J., and Buseck, P. R.  Mixing states of Amazon-basin aerosol particles transported over long distances using transmission electron microscopy.  Atmos. Chem. Phys. Discuss., accepted, doi:10.5194/acp-2020-452 (2020).

Noyes, K. T. J., Kahn, R. A., Sedlacek III, A. J., Kleinman, L. I., Limbacher, J. A., and Li, Z.  Wildfire Smoke Particle Properties and Evolution, from Space-Based Multi-Angle Imaging.  Remote Sensing 12, 769, doi:10.3390/rs12050769 (2020).

Presser, C., Nazarian, A., Chand, D., Conny, J. M., Sedlacek, A., and Hubbe, J. M.  Simultaneous transmission/absorption photometry of particle-laden filters from wildland fires during the Biomass Burning Observation Project (BBOP) field campaign.  Journal of Aerosol Science 150, 105614, doi:10.1016/j.jaerosci.2020.105614 (2020).

Fierce, L., T. B. Onasch, C. Cappa, C. Mazzoleni, S. China, J. Bhandari, P. Davidovits, D. Al Fischer, T. Helgestad, A. Lambe, A. J. Sedlacek III, Geoffrey D. Smith, and L. Wolff.  Radiative absorption enhancements by black carbon controlled by particle-to-particle heterogeneity in composition.  Proc. National Acad. Sci., accepted (2020).

Laing, J. R., Jaffe, D. A., and Sedlacek III, A. J.  Comparison of Filter-Based Absorption Measurements of Biomass Burning Aerosol and Background Aerosol at the Mt. Bachelor Observatory.  Aerosol and Air Quality Research 20, 663-678, doi:10.4209/aaqr.2019.06.0298 (2020).

Zheng, G., A. J. Sedlacek, A. Aiken, Y. Feng, T. Watson, S. Raveh-Rubin, J. Uin, E. Lewis, and J. Wang, Long-range transported North American wildfire aerosols observed in marine boundary layer of eastern North Atlantic.  Environ. International, accepted (2020).

Shou, C., Riemer, N., Onasch, T. B., Sedlacek, A. J., Lambe, A. T., Lewis, E. R., Davidovits, P., and West, M. Mixing state evolution of agglomerating particles in an aerosol chamber: Comparison of measurements and particle-resolved simulations. Aerosol Sci. Tech., accepted, doi:10.1080/02786826.2019.1661959 (2019).

Adachi, K., A. J. Sedlacek III, L. Kleinman, S. R. Springston, J. Wang, D. Chand, J. M. Hubbe, J. E. Shilling, T. B. Onasch, T. Kinase, K. Sakata, Y. Takahashi, and P. R. Buseck.  Formation of tarballs though the aging of liquid organic particles from biomass burning. Proc. Natl Acad. Sci., online, doi:10.1073/pnas.1900129116 (2019).

de Sá, S. S., L. V. Rizzo, B. B. Palm, P. Campuzano-Jost, D. A. Day, L. D. Yee, R. Wernis, G. Isaacman-VanWertz, J. F. Brito, S. Carbone, Y. J. Liu, A. Sedlacek, S. Springston, A. H. Goldstein, H. M. J. Barbosa, M. L. Alexander, P. Artaxo, J. L. Jimenez, and S. T. Martin.   Contributions of biomass-burning, urban, and biogenic emissions to the concentrations and light-absorbing properties of particulate matter in central Amazonia during the dry season.  Atmos. Chem. Phys. 19, 7973-8001, doi:10.5194/acp-19-7973-2019 (2019).

Sedlacek III, A. J., Onasch, T. B., Nichman, L., Lewis, E. R., Davidovits, P., Freedman, A., and Williams, L. Formation of Refractory Black Carbon by SP2-Induced Charring of Organic Aerosol. Aerosol Sci. Technol., online, doi:10.1080/02786826.2018.1531107 (2018).

Zhang, Q., Zhou, S., Collier, S., Jaffe, D., Onasch, T., Shilling, J., Kleinman, L., and Sedlacek, A. Understanding Composition, Formation, and Aging of Organic Aerosols in Wildfire Emissions via Combined Mountain Top and Airborne Measurements. In Multiphase Environmental Chemistry in the Atmosphere, accepted, ACS Symposium Series, 2018.

de Sá, S. S., Palm, B. B., Campuzano-Jost, P., Day, D. A., Hu, W., Isaacman-VanWertz, G., Yee, L. D., Brito, J., Carbone, S., Ribeiro, I. O., Cirino, G. G., Liu, Y., Thalman, R., Sedlacek, A., Funk, A., Schumacher, C., Shilling, J. E., Schneider, J., Artaxo, P., Goldstein, A. H., Souza, R. A. F., Wang, J., McKinney, K. A., Barbosa, H., Alexander, M. L., Jimenez, J. L., and Martin, S. T. Urban influence on the concentration and composition of submicron particulate matter in central Amazonia. Atmos. Chem. Phys. 18, 12185-12206, doi:10.5194/acp-18-12185-2018 (2018).

Forestieri, S. D., Helgestad, T. M., Lambe, A., Renbaum-Wolff, L., Lack, D. A., Massoli, P., Cross, E. S., Dubey, M. K., Mazzoleni, C., Olfert, J., Sedlacek, A. J. Freedman, A., Davidovits, P., Onasch, T. B., and Cappa, C. D. Measurement and modeling of the multi-wavelength optical properties of uncoated flame-generated soot. Atmos. Chem. Phys. 18, 12141-12159, doi:10.5194/acp-2018-306 (2018).

Sedlacek III, A. J., Buseck, P. R., Adachi, K., Onasch, T. B., Springston, S. R., and Kleinman, L. Formation and evolution of Tar Balls from Northwestern US wildfires. Atmos. Chem. Phys. 18, 11289-11301, doi:10.5194/acp-18-11289-2018 (2018).

Kassianov, E., Berg, L., Pekour, M., Barnard, J., Chand, D., Comstock, J., Flynn, C., Sedlacek, A., Shilling, J., Telg, H., Tomlinson, J., Zelenyuk, A., and Fast, J. A Closure Study of Total Scattering Using Airborne In Situ Measurements from the Winter Phase of TCAP. Atmosphere 9, 228, doi:10.3390/atmos9060228 (2018).

Zuidema, P., Sedlacek III, A. J., Flynn, C., Springston, S. R., Delgadillo, R., Zhang, J., Aiken, A. C., Koontz, A., and Muradyan, P. The Ascension Island boundary layer in the remote southeast Atlantic is often smoky. Geophy. Res. Lettrs 45, 4456-4465, doi:10.1002/2017GL076926 (2018).

Creamean, J. M., Maahn, M., de Boer, G., McComiskey, A., Sedlacek, A. J., and Feng, Y. The influence of local oil exploration, regional wildfires, and long range transport on summer 2015 aerosol over the North Slope of Alaska. Aerosol Chem. Phys. 18, 555-570, doi:10.5194/acp-18-555-2018 (2018).

Adachi, A., Sedlacek III, A. J., Kleinman, L., Chand, D., Hubbe, J. M., and Buseck, P. R. Volume changes upon heating of aerosol particles from biomass burning using transmission electron microscopy. Aerosol Sci. Technol. 52, 46-56, doi:10.1080/02786826.2017.1373181 (2018).

Bateman, A. P., Z. Gong, T. H. Harder, S. S. de Sá, B. Wang, P. Castillo, S. China, Y. Liu, R. E. O'Brien, B. Palm, H.-W. Shiu, G. da Silva, R. Thalman, K. Adachi, M. L. Alexander, P. Artaxo, A. K. Bertram, P. R. Buseck, M. K. Gilles, J. L. Jimenez, A. Laskin, A. O. Manzi, A. J. Sedlacek, R. A. F. Souza, J. Wang, R. Zaveri, and S. T. Martin.  Anthropogenic influences on the physical state of submicron particulate matter over a tropical forest.  Atmos. Chem. Phys. 17, 1759-1773 doi:10.5194/acp-17-1759-2017 (2017).

Liu, X., Huey, L. G., Yokelson, R. J., Selimovic, V., Simpson, I. J., Müller, M., Jimenez, J. L., Campuzano-Jost, P., Beyersdorf, A. J., Blake, D. R., Butterfield, Z., Choi, Y., Crounse, J. D., Day, D. A., Diskin, G. S., Dubey, M. K., Fortner, E., Hanisco, T. F., Hu, W., King, L. E., Kleinman, L., Meinardi, S., Mikoviny, T., Onasch, T. B., Palm, B. B., Peischl, J., Pollack, I. B., Ryerson, T. B., Sachse, G. W., Sedlacek, A. J., Shilling, J. E., Springston, S., St. Clair, J. M., Tanner, D. J., Teng, A. P., Wennberg, P. O., Wisthaler, A., and Wolfe, G. M. Airborne measurements of western U.S. wildfire emissions: Comparison with prescribed burning and air quality implications. J. Geophys. Res. Atmos. 122, 6108-6129, doi:10.1002/2016JD026315 (2017).

Presser, C., A. Nazarian, J. M. Conny, D. Chand, A. J. Sedlacek, and J. M. Hubbe.   Absorption/Transmission Measurements of PSAP Particle-Laden Filters from the Biomass Burning Observation Project (BBOP) Field Campaign.  Aerosol Sci. Technol. 51, 451-466, doi:10.1080/02786826.2016.126785 (2017).

Thalman, R., de Sá, S. S., Palm, B. B., Barbosa, H. M. J., Pöhlker, M. L., Alexander, M. L., Brito, J., Carbone, S., Castillo, P., Day, D. A., Kuang, C., Manzi, A., Ng, N. L., Sedlacek III, A. J., Souza, R., Springston, S., Watson, T., Pöhlker, C., Pöschl, U., Andreae, M. O., Artaxo, P., Jimenez, J. L., Martin, S. T., and Wang, J. CCN activity and organic hygroscopicity of aerosols downwind of an urban region in central Amazonia: Seasonal and diel variations and impact of anthropogenic emissions. Atmos. Chem. Phys. 17, 11779-11801, doi:10.5194/acp-17-11779-2017 (2017).

Zhou, S., S. Collier, D. A. Jaffe, N. L. Briggs, J. Hee, A. J. Sedlacek III, L. Kleinman, T. B. Onasch, and Q. Zhang.  Regional Influence of Wildfires on Aerosol Chemistry in the Western US and Insights into Atmospheric Aging of Biomass Burning Organic Aerosol.  Atmos. Chem. Phys. 17, 2477-2493, doi:10.5194/acp-17-2477-2017 (2017).

Fast, J. D., Berg, L. K., Zhang, K., Easter, R. C., Ferrare, R. A., Hair, J. W., Hostetler, C. A., Liu, Y., Ortega, I., Sedlacek, A., Shilling, J. E., Shrivastava, M., Springston, S. R., Tomlinson, J. M., Volkamer, R., Wilson, J., Zaveri, R. A., and Zelenyuk, A. Model representations of aerosol layers transported from North America over the Atlantic Ocean during the Two-Column Aerosol Project. J. Geophys. Res. Atmos. 121, 9814-9848, doi:10.1002/2016JD025248 (2016).

Wang, X., C. Heald, A. Sedlacek III, S. de Sá, S. Martin, L. Alexander, T. Watson, A. Aiken, S. Springston, and P. Artaxo.  Deriving Brown Carbon from Multi-Wavelength Absorption Measurements: Method and Application to AERONET and Surface Observations.  Atmos. Chem. Phys. Discuss. 16, 12733-12752doi:10.5194/acp-2016-237 (2016).

Collier, S., Zhou, S., Onasch, T. B., Jaffe, D. A., Kleinman, L., Sedlacek III, A. J., Briggs, N., Hee, J., Fortner, E., Shilling, J. E., Worsnop, D., Yokelson, R. J., Parworth, C., Ge, X., Xu, J., Butterfield, Z., Chand, D., Dubey, M. K., Pekour, M., Springston, S., and Zhang, Q. Regional Influence of Aerosol Emissions from Wildfires Driven by Combustion Efficiency: Insights from the BBOP Campaign. Environ. Sci. Technol. 50, 8613-8622, doi:10.1021/acs.est.6b01617 (2016).

Nasiri, S., Williamson, A., Cappa, C. D., Kotamarthi, R., Sedlacek, A. J., Flynn, C., Lewis, E., McComiskey, A., and Riemer, N. Absorbing Aerosols Workshop, January 20-21, 2016. Prepared for U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research, Germantown, Formal Report, BNL-112462-2016, July 2016.

Kleinman, L., C. Kuang, A. J., Sedlacek, G. Senum, S. R. Springston, J. Wang, Q. Zhang, J. Jayne, J., Fast, J. Hubbe, J. E Shilling, and R. Zaveri, R.  What do Correlations tell us about Anthropogenic-Biogenic Interactions and SOA Formation in the Sacramento Plume during CARES.  Atmos. Chem. Phys. 16, 1729-1746 (2016).

Berg, L. K., Fast, J. D., Barnard, J. C., Burton, S. P., Cairns, B., Chand, D., Comstock, J. M., Dunagan, S., Ferrare, R. A., Flynn, C. J., Hair, J. W., Hostetler, C. A., Hubbe, J., Jefferson, A., Johnson, R., Kassianov, E. I., Kluzek, C. D., Kollias, P., Lamer, K., Lantz, K., Mei, F., Miller, M. A., Michalsky, J., Ortega, I., Pekour, M., Rogers, R. R., Russell, P. B., Redemann, J., Sedlacek, A. J., Segal-Rosenheimer, M., Schmid, B., Shilling, J. E., Shinozuka, Y., Springston, S. R., Tomlinson, J. M., Tyrrell, M., Wilson, J. M., Volkamer, R., Zelenyuk, A., and Berkowitz, C. M. The Two-Column Aerosol Project: Phase I Overview and impact of elevated aerosol layers on aerosol optical depth. J. Geophys. Res. Atmos. 121, 336-361, doi:10.1002/2015JD023848 (2016).

Kassianov, E., Berg, L. K., Pekour, M., Barnard, J., Chand, D., Flynn, C., Ovchinnikov, M., Sedlacek, A., Schmid, B., Shilling, J., Tomlinson, J., and Fast, J.  Airborne Aerosol In situ Measurements during TCAP: A Closure Study of Total Scattering.  Atmosphere 6(8), 1069-1101, doi:10.3390/atmos6081069 (2015).

Sedlacek, III, A., E. R. Lewis, T. B. Onasch, A. T. Lambe, and P. Davidovits.  Investigation of Refractory Black Carbon-Containing Particle Morphologies Using the Single-Particle Soot Photometer (SP2).  Aerosol Sci. Technol. 49, 872-885 (2015).

Yu, H., Hallar, A. G., You, Y., Sedlacek, A., Springston, S., Kanawade, V. P., Lee, Y.-N., Wang, J., Kuang, C., McGraw, R. L., McCubbin, I., Mikkila, J., and Lee, S.-H. Sub-3 nm particles observed at the coastal and continental sites in the United States.  J. Geophys. Res. Atmos. 119, 860-879, doi:10.1002/ 2013JD020841 (2014).

Shilling, J. E., R. A. Zaveri, J. D. Fast, L. Kleinman, M. L. Alexander, M. R. Canagaratna, E. Fortner, J. M. Hubbe, J. T. Jayne, A. J. Sedlacek III, A. Setyan, S. Springston, D. R. Worsnop, and Q. Zhang.  Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign.  Atmos. Chem. Phys. 13, 2091-2113, doi:10.5194/acp-13-2091-2013 (2013).

Zaveri, R. A., plus 88 co-authors.  Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES).  Atmos. Chem. Phys. 12, 7647-7687 (2012).

Sedlacek, III, Arthur, E. R. Lewis, L. I. Kleinman, J. Xu and Q. Zhang.  Determination of and Evidence for Non-core-shell structure of particles containing black carbon using the single particle soot photometer (SP2).  Geophys. Res. Lett. 39, L06802, doi:10.1029/2012GL050905 (2012).

Kleinman, L. I., P. H. Daum, Y.-N. Lee, E. R. Lewis, A. J. Sedlacek III, G. I. Senum, S. R. Springston, J. Wang, J. Hubbe, J. Jayne, Q. Mi4, S.S. Yum, and G. Allen.  Aerosol concentration and size distribution measured below, in, and above cloud from the DOE G-1 during VOCALS-REx.  Atmos. Chem. Phys. 11, 207-223, doi:10.5194/acp-12-207-2012 (2012).

Lewis, E. R. and A. J. Sedlacek, III.  Interactive comment on “Effective density of Aquadag and fullerene soot black carbon reference materials used for SP2 calibration” by M. Gysel et al.  Atmos. Meas. Tech. Discuss. 4, 4937-4955 (2011).

Cross, Eben S., T. B. Onasch, A. Ahern, W. Wrobel, J. G. Slowik, J. Olfert, D. A. Lack, P. Massoli, C. D. Cappa, J. P. Schwarz, J. R. Spackman, D W. Fahey, Arthur J. Sedlacek, III, A. Trimborn, J. T. Jayne, A. Freedman, L. R. Williams, N. L. Ng, C. Mazzoleni, D. Dubey, B. Brem, G. Kok, R. Subramanian, S. Freitag, A. Clarke, D. Thornhill, L. C. Marr, C. E. Kolb, D. R. Worsnop, and P. Davidovits.  Soot Particle Studies – Instrument Intercomparison – Project Overview.  Aerosol Sci. Technol. 44 (8), 592-611 (2010).

Springston, Stephen R. and Arthur J. Sedlacek, III.  Noise Characteristics of an Instrumental Particle Absorbance Technique.  Aerosol Sci. Technol. 41 (12), 1110-1116 (2007).

Sedlacek, III, Arthur J. and Jeonghoon Lee, Photothermal Interferometric Aerosol Absorption Spectrometry.  Aerosol Sci. Technol. 41 (12), 1089-1101 (2007).

Sedlacek, III, Arthur J.  Real-time Detection of Ambient Aerosols using Photothermal Interferometry: Folded Jamin Interferometer.  Rev. Sci. Instrum. 77, 064903 (2006).

Heiser, John H., and Arthur J. Sedlacek, III.  Using Lidar to Measure Perfluorocarbon Tracers for the Verification and Monitoring of Cap and Cover Systems.  Water Air Soil Pollut. 170, 345-357 (2006).

Vig, John, E. Heijne, W. Hunt, R. Lareau, Arthur J. Sedlacek, III, T. Swager, E. Towe,  Guest Editor for Special Issue:  “Sensors for the Prevention of Terrorist Acts”.  IEEE Sensors Journal 5 (4) (2005).

Sedlacek III, Arthur. J., M. D. Ray and M. Wu, Application of UV Raman Scattering to Non- Traditional Stand-off Chemical Detection, Trends in Applied Spectroscopy. 5, 19-38 (2004).

Sedlacek III, Arthur J., Steven D. Christesen, Richard Colton and Tuan VoDinh; Editors SPIE Proceedings: Chemical and Biological Point Sensors for Homeland Defense , October 27- 31, 2003 in Providence, RI, 5269 (2003).

T. H. Chyba, N. S. Higdon, W. T. Armstrong, C.T. Lobb, P. L. Ponsardin, D. A. Richter, B. T. Kelly, Q. Bui, R. Babnick, M. K. Boysworth, Arthur J. Sedlacek, S. D. Christesen, M. P. Sennett, A. A. Johnson, J. A. Nordin, and L. A Silks, Tests of the Laser Interrogation of Surface Agents (LISA) system for on-the-move Standoff Sensing of Chemical Agents, International Symposium on Spectral Sensing Research (ISSSR) 2003 proceedings.