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Measuring Elemental Carbon in Occupational Environments
Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Carbonaceous aerosol particles from combustion, such as diesel exhaust particles (DEP), harm human health and affect the Earth’s radiative system.Elemental carbon (EC) has been proposed to be used as a marker of DEP. The objective of this thesis was to investigate the EC levels in different environments, to compare methods for measuring EC and investigate confounding factors that influence EC. The five papers concluded the following:

  •  A study of asphalt paving work showed levels of respirable EC at 3 µg m-3 and organic carbon (OC) level at 42 µg m-3. The concentration of OC was not high enough to disturb the light absorption of EC in the analysis. The EC/TC ratio 0.067 indicated a large contribution of OC from the asphalt fumes.
  • Water-soluble organic compounds (WSOC) were used to show that samples with wood smoke particles, both single source and ambient, resulted in a positive bias of 10-20 % in EC due to WSOC, but not for samples with DEP.
  • Well-defined single source samples of DEP gave differing EC and even total carbon levels in an intercomparison between three different analysing methods. Bio fuels such as vegetable oils, animal fat and natural gas showed very large difference in the amount of EC.
  • A study of aerosol in the subway shows that iron oxides interfere with the analysis of EC. Analytical result and the oxidation state of iron in samples after analysis differed between NIOSH and IMPROVE. Optical measurements of Black Carbon (BC) in the subway were higher than at street level, which was suspected to be an overestimation of BC due to iron oxides.
  • The apparent attenuation cross section, σATN (m2/g) was compared for different samples, different protocols and varying load during thermo-optical analysis to validate the setting of the OC/EC split point. The results indicating a mixed combustion of pyrolytic carbon with EC and the assumptions forming the basis for setting a proper split time between EC and OC do not seem to be valid.
Place, publisher, year, edition, pages
Stockholm: Department of Applied Environmental Science (ITM), Stockholm University , 2011. , 24 p.
Keyword [en]
Diesel Exhaust Particles, Thermo-Optical Analysis, Black Carbon, Pyrolytic Carbon, Wood Smoke Particles, Water Soluble Organic Compounds, Asphalt Paving Work, Bio Fuels, Subway Aerosol
National Category
Natural Sciences
Research subject
Applied Environmental Science
Identifiers
URN: urn:nbn:se:su:diva-61732ISBN: 978-91-7447-334-6 (print)OAI: oai:DiVA.org:su-61732DiVA: diva2:437286
Public defence
2011-09-30, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 12, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript: Paper 3: Submitted. Paper 5 Submitted.Available from: 2011-09-08 Created: 2011-08-29 Last updated: 2011-08-29Bibliographically approved
List of papers
1. Exposure to Ultrafine Particles in Asphalt Work
Open this publication in new window or tab >>Exposure to Ultrafine Particles in Asphalt Work
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2008 (English)In: Journal of Occupational and Environmental Hygiene, ISSN 1545-9624, E-ISSN 1545-9632, Vol. 5, 771-779 p.Article in journal (Refereed) Published
Keyword
Environmental science
Identifiers
urn:nbn:se:su:diva-19000 (URN)10.1080/15459620802473891 (DOI)000260498300004 ()
Available from: 2009-02-19 Created: 2009-02-19 Last updated: 2017-12-13Bibliographically approved
2. An attempt to differentiate between pyrolysing and elemental carbon in thermo-optical analysis
Open this publication in new window or tab >>An attempt to differentiate between pyrolysing and elemental carbon in thermo-optical analysis
(English)Manuscript (preprint) (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-61728 (URN)
Available from: 2011-08-29 Created: 2011-08-29 Last updated: 2011-08-29Bibliographically approved
3. Intercomparison of three analytical Methods for Elemental Carbon in Filter Samples from Doesel Engine Exhaust and a Test Aerosol Generator
Open this publication in new window or tab >>Intercomparison of three analytical Methods for Elemental Carbon in Filter Samples from Doesel Engine Exhaust and a Test Aerosol Generator
(English)Article in journal (Other academic) Submitted
Identifiers
urn:nbn:se:su:diva-61726 (URN)
Available from: 2011-08-29 Created: 2011-08-29 Last updated: 2011-08-29Bibliographically approved
4. Measured elemental carbon by thermo-optical transmittance analysis in water-soluble extracts from diesel exhaust, woodsmoke, and ambient particulate samples
Open this publication in new window or tab >>Measured elemental carbon by thermo-optical transmittance analysis in water-soluble extracts from diesel exhaust, woodsmoke, and ambient particulate samples
2010 (English)In: Journal of Occupational and Environmental Hygiene, ISSN 1545-9624, E-ISSN 1545-9632, Vol. 7, no 1, 35-45 p.Article in journal (Refereed) Published
Abstract [en]

Elemental carbon has been proposed as a marker of diesel particulate matter. The objective of this study was to investigate if water-soluble carbonaceous compounds could be responsible for positive bias of elemental carbon using NIOSH Method 5040 with a thermo-optical carbon transmittance analyzer. Filter samples from eight different aerosol environments were used: pure diesel exhaust fume with a high content of elemental carbon, pure diesel exhaust fume with a low content of elemental carbon, pure biodiesel exhaust fume, pure woodsmoke, an urban road tunnel, an urban street canyon, an urban background site, and residential woodburning in an urban area. Part of each filter sample was analyzed directly with a thermo-optical carbon analyzer, and another part was extracted with water. This water-soluble extract was filtered to remove particles, spiked onto filter punches, and analyzed with a thermo-optical transmittance carbon analyzer. The ratio of elemental carbon in the water-soluble extract to the particulate sample measurement was 18, 12, and 7%, respectively, for the samples of pure woodsmoke, residential woodburning, and urban background. Samples with diesel particulate matter and ambient samples with motor exhaust detected no elemental carbon in the water-soluble extract. Since no particles were present in the filtered water-soluble extract, part of the water-soluble organic carbon species, existing or created during analysis, are misclassified as elemental carbon with this analysis. The conclusion is that in measuring elemental carbon in particulate aerosol samples with thermo-optical transmittance analysis, woodsmoke, and biomass combustion samples show a positive bias of elemental carbon. The water-soluble EC could be used as a simple method to indicate other sources, such as wood or other biomass combustion aerosol particles.

Place, publisher, year, edition, pages
Philadelphia, PA: Taylor and Francis, 2010
National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-34631 (URN)10.1080/15459620903368859 (DOI)000271650200006 ()19904658 (PubMedID)
Available from: 2010-01-11 Created: 2010-01-11 Last updated: 2017-12-12Bibliographically approved
5. A multi-analytical assessment of nano to micron-sized subway particles
Open this publication in new window or tab >>A multi-analytical assessment of nano to micron-sized subway particles
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(English)Article in journal (Other academic) Submitted
Identifiers
urn:nbn:se:su:diva-61725 (URN)
Available from: 2011-08-29 Created: 2011-08-29 Last updated: 2011-08-29Bibliographically approved

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