Articles | Volume 5, issue 8
Atmos. Meas. Tech., 5, 1869–1887, 2012
Atmos. Meas. Tech., 5, 1869–1887, 2012

Review article 02 Aug 2012

Review article | 02 Aug 2012

Soot reference materials for instrument calibration and intercomparisons: a workshop summary with recommendations

D. Baumgardner1, O. Popovicheva2, J. Allan3, V. Bernardoni4, J. Cao5, F. Cavalli6, J. Cozic7, E. Diapouli8, K. Eleftheriadis8, P. J. Genberg9, C. Gonzalez10, M. Gysel11, A. John12, T. W. Kirchstetter13, T. A. J. Kuhlbusch12,14, M. Laborde11, D. Lack15,16, T. Müller17, R. Niessner18, A. Petzold19, A. Piazzalunga20, J. P. Putaud6, J. Schwarz15,16, P. Sheridan15, R. Subramanian21, E. Swietlicki9, G. Valli4, R. Vecchi4, and M. Viana22 D. Baumgardner et al.
  • 1Centro Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City, Mexico
  • 2Nuclear Physics, Moscow, State University, Moscow, Russia
  • 3University of Manchester, Manchester, UK
  • 4Department of Physics, Università degli Studi di Milano & National Institute of Nuclear Physics, Milan, Italy
  • 5Institute of Earth Environment, Chinese Academy of Sciences, Xian, China
  • 6European Commision – Joint Research Centre – Institute for Environment and Sustainability, Ispra, Italy
  • 7Laboratory of Glaciology and Geophysics of the Environment, St Martin d'Hères Cedex, France
  • 8E.R.L, Institute of Nuclear Technology & Radiation Protection, N.C.S.R. Demokritos, 15310, Attiki, Greece
  • 9Div. of Nuclear Physics, Lund University, P.O. Box 118, 22100, Lund, Sweden
  • 10National Institute of Standards and Technology, Gaithersburg, MD, USA
  • 11Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, Switzerland
  • 12IUTA e.v., Air Quality & Sustainable Nanotechnology Unit, Duisburg, Germany
  • 13Lawrence Berkeley National Laboratory, Berkeley, CA, USA
  • 14King's College London, Environmental Research Group, London, UK
  • 15Earth Systems Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA
  • 16Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA
  • 17Leibniz Institute for Tropospheric Research, Leipzig, Germany
  • 18Technische Universität, München, Germany
  • 19Deutschen Zentrums für Luft- und Raumfahrt, Oberpfaffenhofen, Germany
  • 20Department of Environmental and Territorial Sciences, University of Milan-Bicocca & Department of Inorganic, Metallorganic and Analytical Chemistry, Università degli Studi di Milano, Milan, Italy
  • 21RTI, Research Triangle, NC, USA
  • 22IDAEA-CSIC: Institute for Environmental Assessment and Water Research (IDǼA), Spanish Research Council – CSIC, Barcelona, Spain

Abstract. Soot, which is produced from biomass burning and the incomplete combustion of fossil and biomass fuels, has been linked to regional and global climate change and to negative health problems. Scientists measure the properties of soot using a variety of methods in order to quantify source emissions and understand its atmospheric chemistry, reactivity under emission conditions, interaction with solar radiation, influence on clouds, and health impacts. A major obstacle currently limiting progress is the absence of established standards or reference materials for calibrating the many instruments used to measure the various properties of soot.

The current state of availability and practicability of soot standard reference materials (SRMs) was reviewed by a group of 50 international experts during a workshop in June of 2011. The workshop was convened to summarize the current knowledge on soot measurement techniques, identify the measurement uncertainties and limitations related to the lack of soot SRMs, and identify attributes of SRMs that, if developed, would reduce measurement uncertainties. The workshop established that suitable SRMs are available for calibrating some, but not all, measurement methods. The community of users of the single-particle soot-photometer (SP2), an instrument using laser-induced incandescence, identified a suitable SRM, fullerene soot, but users of instruments that measure light absorption by soot collected on filters did not. Similarly, those who use thermal optical analysis (TOA) to analyze the organic and elemental carbon components of soot were not satisfied with current SRMs. The workshop, and subsequent, interactive discussions, produced a number of recommendations for the development of new SRMs, and their implementation, that would be suitable for the different soot measurement methods.