Equivalence of Elemental Carbon by Thermal/Optical Reflectance and Transmittance with Different Temperature Protocols
Abstract
Charring of organic carbon (OC) during thermal/optical analysis is monitored by the change in a laser signal either reflected from or transmitted through a filter punch. Elemental carbon (EC) in suspended particulate matter collected on quartz-fiber filters is defined as the carbon that evolves after the detected optical signal attains the value it had prior to commencement of heating, with the rest of the carbon classified as organic carbon (OC). Heretofore, operational definitions of EC were believed to be caused by different temperature protocols rather than by the method of monitoring charring. This work demonstrates that thermal/ optical reflectance (TOR) corrections yield equivalent OC/ EC splits for widely divergent temperature protocols. EC results determined by simultaneous thermal/optical transmittance (TOT) corrections are 30% lower than TOR for the same temperature protocol and 70-80% lower than TOR for a protocol with higher heating temperatures and shorter residence times. This is true for 58 urban samples from Fresno, CA, as well as for 30 samples from the nonurban IMPROVE network that are individually dominated by wildfire, vehicle exhaust, secondary organic aerosol, and calcium carbonate contributions. Visual examination of filter darkening at different temperature stages shows that substantial charring takes place within the filter, possibly due to adsorbed organic gases or diffusion of vaporized particles. The filter transmittance is more influenced by the…
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Studies of Fairbanks pollution have only used standard OC/elemental carbon analysis, which has little information about the actual chemical structures of the organic carbon species.
“The studies of Fairbanks pollution, for example, have only used standard OC/elemental carbon analysis (Chow et al., 2004), which has little information about the actual chemical structures of the organic carbon species.”
From Local Arctic Air Pollution: A Neglected but Serious Problem (2018) · cites this paper as Chow et al., 2004
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Mass reconstruction methods for PM2.5: a review
Chow, J. C., Lowenthal, D. H., Chen, L.-W. A., Wang, X., & Watson, J. G. (2015) · Air Quality, Atmosphere & Health · doi:10.1007/s11869-015-0338-3 · Cited by 379 · see citing works
Self-citationLocal Arctic Air Pollution: A Neglected but Serious Problem
Schmale, J., Arnold, S. R., Law, K. S., Thorp, T., Anenberg, S., Simpson, W. R., Mao, J., & Pratt, K. A. (2018) · Earth's Future · doi:10.1029/2018ef000952 · Cited by 219 · see citing works
“The studies of Fairbanks pollution, for example, have only used standard OC/elemental carbon analysis (Chow et al., 2004), which has little information about the actual chemical structures of the organic carbon species.”
Method
- Authors
- Chow, J. C., Watson, J. G., Chen, L.-W. A., Arnott, W. P., Moosmüller, H., & Fung, K.
- Affiliations
- Desert Research Institute (US)
- Atmoslytic Inc., 24801 Alexandra Court, Calabasas, California 91302
- Corresponding author
- Chow, Judith C.
- Venue
- Environmental Science & Technology
- Publisher
- American Chemical Society (ACS)
- Published
- 2004-07-20
- Volume
- 38
- Issue
- 16
- Pages
- 4414-4422
- ISSN
- 0013-936X (ISSN-L)
- 1520-5851
- OpenAlex
- W1998643121
- Cited by
- 652
- References
- 0
- Citations by year
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- FWCI
- 13.07
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Environmental Science & Technology (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Physical Sciences › Earth and Planetary Sciences › Atmospheric Science › Atmospheric chemistry and aerosols
- Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Toxic Organic Pollutants Impact
- Physical Sciences › Environmental Science › Global and Planetary Change › Atmospheric aerosols and clouds
- Keywords
- elemental carbon, organic carbon, particulate matter, suspended particulate matter, primary organic carbon, urban aerosols, IMPROVE network, wildfire aerosols, vehicle emissions, secondary organic aerosol, calcium carbonate
- MeSH terms
- Adsorption, Carbon, Environmental Monitoring, Filtration, Temperature, Optics and Photonics
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