(24-130408-A) Recommendations for the Interpretation of "Black Carbon" Measurements
J.A. Ogren1, A. Petzold2, M. Fiebig3, P. Laj4, S. Li5, U. Baltensperger6, T. Holzer-Popp7, S. Kinne8, G. Pappalardo9, N. Sugimoto10, C. Wehrli11, A. Wiedensohler12 and X. Zhang13
1NOAA Earth System Research Laboratory, 325 Broadway, Boulder, CO 80305; 303-497-6210, E-mail: John.A.Ogren@noaa.gov
2Forschungszentrum Jülich GmbH, Jülich, Germany
3Norwegian Institute for Air Research, Kjeller, Norway
4Laboratoire de Glaciologie et Géophysique de lEnvironement, University of Grenoble, Grenoble, France
5Environment Canada, Toronto, Ontario M3H 5T4, Canada
6Paul Scherrer Institute, Laboratory of Atmospheric Chemistry, Villigen CH-5232, Switzerland
7Deutsches Fernerkundungsdatenzentrum, DLR, Oberpfaffenhofen, Germany
8Max Planck Institute for Meteorology, Hamburg, Germany
9Istituto di Metodologie per l'Analisi Ambientale CNR-IMAA, Potenza, Italy
10National Institute for Environmental Studies, Tsukuba-City, Ibaraki, Japan
11Physikalisch-Meteorologisches Observatorium, Davos, Switzerland
12Leibniz Institute for Tropospheric Research, Leipzig, Germany
13China Meteorological Administration, Chinese Academy of Meteorological Sciences, Beijing, China
Although Black Carbon (BC) is one of the key atmospheric particulate components driving climate change and air quality, there is no agreement on the terminology that considers all aspects of specific properties, definitions, measurement methods, and related uncertainties. As a result, there is much ambiguity in the scientific literature of measurements and numerical models that refer to BC with different names and based on different properties of the particles, with no clear definition of the terms. A recommended terminology is presented to clarify the terms used for BC in atmospheric research, with the goal of establishing unambiguous links between terms, targeted material properties and associated measurement techniques. Briefly, the recommendations are:
- Black Carbon (BC) is a useful qualitative description when referring to light-absorbing carbonaceous substances in atmospheric aerosol; however, for quantitative applications the term requires clarification of the underlying determination.
- Equivalent Black Carbon (EBC) should be used instead of black carbon for data derived from optical absorption methods, together with a suitable mass absorption coefficient for the conversion of light absorption coefficient into mass concentration.
- Elemental Carbon (EC) should be used instead of black carbon for data derived from methods that are specific to the carbon content of carbonaceous matter.
- refractory Black Carbon (rBC) should be used instead of black carbon for measurements derived from incandescence methods.
- Soot is a useful qualitative description when referring to carbonaceous particles formed from incomplete combustion.
Figure 1. Confusion over black carbon terminology: The parable of the blind men and the elephant.