Pitfalls with the use of enhancement ratios or normalized excess mixing ratios measured in plumes to characterize pollution sources and aging
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Abstract
Abstract. Normalized excess mixing ratios (NEMRs), also known as enhancement ratios, are a common way to characterize plumes of pollution in atmospheric research. As single-source pollutant plumes disperse in the atmosphere, they are diluted by mixing with the adjacent background air. Changes in the composition of this background air can cause large changes to the NEMR that is subsequently measured by remote-sensing, airborne, or ground-based instruments. This scenario is common when boundary layer plumes enter the free troposphere and could also impact long-range transport or plumes near the top of the troposphere. We provide a context for these issues and an example showing that neglect of this effect could lead to serious errors in data interpretation.
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When an enhancement ratio does not change with dilution and mixing with background air, it equals the emission ratio of a source.
“When an enhancement ratio does not change with dilution and mixing with background air, then the enhancement ratio is equal to the emission ratio (ER) of a source (Yokelson et al., 2013).”
From Ground solar absorption observations of total column CO, CO <sub>2</sub> , CH <sub>4</sub> , and aerosol optical depth from California's Sequoia Lightning Complex Fire: emission factors and modified combustion efficiency at regional scales (2023) · cites this paper as Yokelson et al., 2013
The Discussion and conclusions states that an enhancement ratio remains equal to the source emission ratio despite dilution when the source emission ratio and background composition are fixed and neither measured species is produced or lost. The citing sentence omits these conditions, so an unchanged ratio under dilution alone does not establish the stated equality. (LLM, conf=0.86)
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Research works printed but not linked: 8
- Akagi, S. K., Yokelson, R. J., Wiedinmyer, C., Alvarado, M. J., Reid, J. S., Karl, T., Crounse, J. D., and Wennberg, P. O.: Emis- sion factors for open and domestic biomass burning for use in atmospheric models, Atmos. Chem. Phys., 11, 4039-4072, doi:10.5194/acp-11-4039-2011, 2011. · DOI · Paper page
- Akagi, S. K., Craven, J. S., Taylor, J. W., McMeeking, G. R., Yokel- son, R. J., Burling, I. R., Urbanski, S. P., Wold, C. E., Seinfeld, J. H., Coe, H., Alvarado, M. J., and Weise, D. R.: Evolution of trace gases and particles emitted by a chaparral fire in California, Atmos. Chem. Phys., 12, 1397-1421, doi:10.5194/acp-12-1397- 2012, 2012. · DOI
- Andreae, M. O. and Merlet, P.: Emission of trace gases and aerosols from biomass burning, Global Biogeochem. Cy., 15, 955-966, doi:10.1029/2000GB001382, 2001. · DOI
- Andreae, M. O., Artaxo, P., Beck, V., Bela, M., Freitas, S., Gerbig, C., Longo, K., Munger, J. W., Wiedemann, K. T., and Wofsy, S. C.: Carbon monoxide and related trace gases and aerosols over the Amazon Basin during the wet and dry seasons, Atmos. Chem. Phys., 12, 6041-6065, doi:10.5194/acp-12-6041-2012, 2012. · DOI
- Guyon, P., Frank, G. P., Welling, M., Chand, D., Artaxo, P., Rizzo, L., Nishioka, G., Kolle, O., Fritsch, H., Silva Dias, M. A. F, Gatti, L. V., Cordova, A. M., and Andreae, M. O.: Airborne measurements of trace gas and aerosol particle emissions from biomass burning in Amazonia, Atmos. Chem. Phys., 5, 2989- 3002, doi:10.5194/acp-5-2989-2005, 2005. · DOI
- Hobbs, P. V., Sinha, P., Yokelson, R. J., Christian, T. J., Blake, D. R., Gao, S., Kirchstetter, T. W., Novakov, T., and Pilewskie, P.: Evo- lution of gases and particles from a savanna fire in South Africa, J. Geophys. Res., 108, 8485, doi:10.1029/2002JD002352, 2003. · DOI
- Nowak, J. B., Parrish, D. D., Neuman, J. A., Holloway, J. S., Cooper, O. R., Ryerson, T. B., Nicks Jr., D. K., Flocke, F., Roberts, J. M., Atlas, E., de Gouw, J. A., Donnelly, S., Dun- lea, E., Hübler, G., Huey, L. G., Schauffler, S., Tanner, D. J., Warneke, C., and Fehsenfeld, F. C.: Gas-phase chemical charac- teristics of Asian emission plumes observed during ITCT 2K2 over the eastern North Pacific Ocean, J. Geophys. Res., 109, D23S19, doi:10.1029/2003JD004488, 2004. · DOI
- Parrish, D. D., Stohl, A., Forster, C., Atlas, E. L., Blake, D. R., Goldan, P. D., Kuster, W. C., and de Gouw, J. A.: Effects of mix- ing on evolution of hydrocarbon ratios in the troposphere, J. Geo- phys. Res., 112, D10S34, doi:10.1029/2006JD007583, 2007. · DOI
Cited by
Sorted by citations
Frausto-Vicencio, I., Heerah, S., Meyer, A. G., Parker, H. A., Dubey, M., & Hopkins, F. M. (2023) · Atmospheric Chemistry and Physics · doi:10.5194/acp-23-4521-2023 · Cited by 10 · see citing works
“When an enhancement ratio does not change with dilution and mixing with background air, then the enhancement ratio is equal to the emission ratio (ER) of a source (Yokelson et al., 2013).”
Background
- Authors
- Yokelson, R. J., Andreae, M. O., & Akagi, S. K.
- Affiliations
- University of Montana (US)
- Scripps Institution of Oceanography (US)
- Corresponding author
- Yokelson, R. J.
- Andreae, M. O.
- Venue
- Atmospheric Measurement Techniques
- Publisher
- Copernicus GmbH
- Published
- 2013-08-28
- Volume
- 6
- Issue
- 8
- Pages
- 2155-2158
- ISSN
- 1867-1381 (ISSN-L)
- 1867-8548
- OpenAlex
- W2123080673
- Cited by
- 93
- References
- 0
- Citations by year
- 2026: 3 · 2025: 9 · 2024: 12 · 2023: 4 · 2022: 3 · 2021: 8 · 2020: 15 · 2019: 7 · 2018: 4 · 2017: 8 · 2016: 9 · 2015: 2 · 2014: 7 · 2013: 2
- FWCI
- 4.34
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Atmospheric measurement techniques (publishedVersion, cc-by)
- The Mathematics Enthusiast (submittedVersion, cc-by)
- DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
- Max Planck Institute for Plasma Physics (submittedVersion)
- MPG.PuRe (Max Planck Society) (submittedVersion)
- Topics
- Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Atmospheric chemistry and aerosols
- Physical Sciences › Environmental Science › Global and Planetary Change › Atmospheric and Environmental Gas Dynamics
- Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Atmospheric Ozone and Climate
- Keywords
- enhancement ratio, pollutant plume, free troposphere, long-range transport
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