Investigation of the absorption Ångström exponent and its relation to physicochemical properties for mini-CAST soot
(2018) In Aerosol Science and Technology 52(7). p.757-767- Abstract
In this work, a mini-CAST soot generator was used to produce soot with different optical and physicochemical characteristics. Absorption Ångström exponents (AAE) expressing the absorption wavelength dependence were assessed by multiwavelength in-situ and filter-based (aethalometer) laser extinction. The two optical techniques showed good agreement. For the chosen mini-CAST operating conditions, AAEs between 1 and 3.5 were found. Soot with high mass-fractions of organic carbon (OC) and pyrolytic carbon (PC) determined with thermal optical analysis were associated with AAEs significantly higher than 1. Heating to 250 and 500°C removed the majority of polycyclic aromatic hydrocarbons. However, the thermal-optical analysis revealed that OC... (More)
In this work, a mini-CAST soot generator was used to produce soot with different optical and physicochemical characteristics. Absorption Ångström exponents (AAE) expressing the absorption wavelength dependence were assessed by multiwavelength in-situ and filter-based (aethalometer) laser extinction. The two optical techniques showed good agreement. For the chosen mini-CAST operating conditions, AAEs between 1 and 3.5 were found. Soot with high mass-fractions of organic carbon (OC) and pyrolytic carbon (PC) determined with thermal optical analysis were associated with AAEs significantly higher than 1. Heating to 250 and 500°C removed the majority of polycyclic aromatic hydrocarbons. However, the thermal-optical analysis revealed that OC and PC were abundant in the soot with AAE > 2 also after heating the aerosol. Analysis of mass absorption cross section ratios for elemental carbon and OC indicated that elevated AAEs also after heating to 500°C could be related to persistent OC and PC components and/or the refractory soot. By comparing the mini-CAST soot optical properties with soot properties derived from in-situ extinction measurements in a premixed flame, mini-CAST soot with a higher AAE could be identified as less mature soot.
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- author
- Török, Sandra LU ; Malmborg, Vilhelm B. LU ; Simonsson, Johan LU ; Eriksson, Axel LU ; Martinsson, Johan LU ; Mannazhi, Manu LU ; Pagels, Joakim LU and Bengtsson, Per Erik LU
- organization
- publishing date
- 2018-04-16
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Aerosol Science and Technology
- volume
- 52
- issue
- 7
- pages
- 757 - 767
- publisher
- Taylor & Francis
- external identifiers
-
- scopus:85045834020
- ISSN
- 0278-6826
- DOI
- 10.1080/02786826.2018.1457767
- language
- English
- LU publication?
- yes
- id
- d53b849c-713c-48fd-8bae-02cc9db4329e
- date added to LUP
- 2018-05-04 10:00:33
- date last changed
- 2024-01-14 19:44:26
@article{d53b849c-713c-48fd-8bae-02cc9db4329e, abstract = {{<p>In this work, a mini-CAST soot generator was used to produce soot with different optical and physicochemical characteristics. Absorption Ångström exponents (AAE) expressing the absorption wavelength dependence were assessed by multiwavelength in-situ and filter-based (aethalometer) laser extinction. The two optical techniques showed good agreement. For the chosen mini-CAST operating conditions, AAEs between 1 and 3.5 were found. Soot with high mass-fractions of organic carbon (OC) and pyrolytic carbon (PC) determined with thermal optical analysis were associated with AAEs significantly higher than 1. Heating to 250 and 500°C removed the majority of polycyclic aromatic hydrocarbons. However, the thermal-optical analysis revealed that OC and PC were abundant in the soot with AAE > 2 also after heating the aerosol. Analysis of mass absorption cross section ratios for elemental carbon and OC indicated that elevated AAEs also after heating to 500°C could be related to persistent OC and PC components and/or the refractory soot. By comparing the mini-CAST soot optical properties with soot properties derived from in-situ extinction measurements in a premixed flame, mini-CAST soot with a higher AAE could be identified as less mature soot.</p>}}, author = {{Török, Sandra and Malmborg, Vilhelm B. and Simonsson, Johan and Eriksson, Axel and Martinsson, Johan and Mannazhi, Manu and Pagels, Joakim and Bengtsson, Per Erik}}, issn = {{0278-6826}}, language = {{eng}}, month = {{04}}, number = {{7}}, pages = {{757--767}}, publisher = {{Taylor & Francis}}, series = {{Aerosol Science and Technology}}, title = {{Investigation of the absorption Ångström exponent and its relation to physicochemical properties for mini-CAST soot}}, url = {{http://dx.doi.org/10.1080/02786826.2018.1457767}}, doi = {{10.1080/02786826.2018.1457767}}, volume = {{52}}, year = {{2018}}, }