Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition
A variety of tools are used to simulate atmospheric aging, including smog chambers and flow reactors. Traditional, large-scale smog chambers age emissions over the course of hours to days, whereas flow reactors rapidly age emissions using high oxidant concentrations to reach higher degrees of oxygen...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/8/2315/2015/amt-8-2315-2015.pdf |
| _version_ | 1811288571131199488 |
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| author | E. A. Bruns I. El Haddad A. Keller F. Klein N. K. Kumar S. M. Pieber J. C. Corbin J. G. Slowik W. H. Brune U. Baltensperger A. S. H. Prévôt |
| author_facet | E. A. Bruns I. El Haddad A. Keller F. Klein N. K. Kumar S. M. Pieber J. C. Corbin J. G. Slowik W. H. Brune U. Baltensperger A. S. H. Prévôt |
| author_sort | E. A. Bruns |
| collection | DOAJ |
| description | A variety of tools are used to simulate atmospheric aging, including smog
chambers and flow reactors. Traditional, large-scale smog chambers age
emissions over the course of hours to days, whereas flow reactors rapidly
age emissions using high oxidant concentrations to reach higher degrees of
oxygenation than typically attained in smog chamber experiments. The
atmospheric relevance of the products generated under such rapid oxidation
warrants further study. However, no previously published studies have
compared the yields and chemical composition of products generated in flow
reactors and smog chambers from the same starting mixture.
<br><br>
The yields and composition of the organic aerosol formed from the
photo-oxidation of α-pinene and of wood-combustion emissions in a
smog chamber (SC) and two flow reactors: a potential aerosol mass reactor
(PAM) and a micro-smog chamber (MSC), were determined using aerosol mass
spectrometry. Reactants were sampled from the SC and aged in the MSC and the PAM
using a range of hydroxyl radical (OH) concentrations and then
photo-chemically aged in the SC.
<br><br>
The chemical composition, as well as the maximum yields and emission
factors, of the products in both the α-pinene and wood-combustion
systems determined with the PAM and the SC agreed reasonably well. High OH
exposures have been shown previously to lower yields by breaking
carbon–carbon bonds and forming higher volatility species, which reside
largely in the gas phase; however, fragmentation in the PAM was not
observed. The yields determined using the PAM for the α-pinene
system were slightly lower than in the SC, possibly from increased wall
losses of gas phase species due to the higher surface area to volume ratios
in the PAM, even when offset with better isolation of the sampled flow from
the walls. The α-pinene SOA results for the MSC were not directly
comparable, as particles were smaller than the optimal AMS transmission
range. The higher supersaturation in the flow reactors resulted in more
nucleation than in the SC. For the wood-combustion system, emission factors
measured from the MSC were typically lower than those measured from the SC.
Lower emission factors in the MSC may have been due to considerable
nucleation mode particles formed in the MSC which were not detected by the
AMS or due to condensational loss of gases to the walls inside or after the
MSC. More comprehensive coverage of the potential particle size range is
needed in future SOA measurements to improve our understanding of the
differences in yields when comparing the MSC to the SC. The PAM and the SC
agreed within measurement uncertainties in terms of yields and
composition for the systems and conditions studied here and this agreement
supports the continued use of the PAM to study atmospheric aging. |
| first_indexed | 2024-04-13T03:39:14Z |
| format | Article |
| id | doaj.art-e2bdef215ef8476c96caba691611314d |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-13T03:39:14Z |
| publishDate | 2015-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-e2bdef215ef8476c96caba691611314d2022-12-22T03:04:13ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482015-06-01862315233210.5194/amt-8-2315-2015Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and compositionE. A. Bruns0I. El Haddad1A. Keller2F. Klein3N. K. Kumar4S. M. Pieber5J. C. Corbin6J. G. Slowik7W. H. Brune8U. Baltensperger9A. S. H. Prévôt10Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandInstitute for Aerosol and Sensor Technology, University of Applied Sciences, Northwestern Switzerland, Windisch, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandDepartment of Meteorology, Pennsylvania State University, University Park, Pennsylvania, USALaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandLaboratory of Atmospheric Chemistry, Paul Scherrer Institute, Villigen, SwitzerlandA variety of tools are used to simulate atmospheric aging, including smog chambers and flow reactors. Traditional, large-scale smog chambers age emissions over the course of hours to days, whereas flow reactors rapidly age emissions using high oxidant concentrations to reach higher degrees of oxygenation than typically attained in smog chamber experiments. The atmospheric relevance of the products generated under such rapid oxidation warrants further study. However, no previously published studies have compared the yields and chemical composition of products generated in flow reactors and smog chambers from the same starting mixture. <br><br> The yields and composition of the organic aerosol formed from the photo-oxidation of α-pinene and of wood-combustion emissions in a smog chamber (SC) and two flow reactors: a potential aerosol mass reactor (PAM) and a micro-smog chamber (MSC), were determined using aerosol mass spectrometry. Reactants were sampled from the SC and aged in the MSC and the PAM using a range of hydroxyl radical (OH) concentrations and then photo-chemically aged in the SC. <br><br> The chemical composition, as well as the maximum yields and emission factors, of the products in both the α-pinene and wood-combustion systems determined with the PAM and the SC agreed reasonably well. High OH exposures have been shown previously to lower yields by breaking carbon–carbon bonds and forming higher volatility species, which reside largely in the gas phase; however, fragmentation in the PAM was not observed. The yields determined using the PAM for the α-pinene system were slightly lower than in the SC, possibly from increased wall losses of gas phase species due to the higher surface area to volume ratios in the PAM, even when offset with better isolation of the sampled flow from the walls. The α-pinene SOA results for the MSC were not directly comparable, as particles were smaller than the optimal AMS transmission range. The higher supersaturation in the flow reactors resulted in more nucleation than in the SC. For the wood-combustion system, emission factors measured from the MSC were typically lower than those measured from the SC. Lower emission factors in the MSC may have been due to considerable nucleation mode particles formed in the MSC which were not detected by the AMS or due to condensational loss of gases to the walls inside or after the MSC. More comprehensive coverage of the potential particle size range is needed in future SOA measurements to improve our understanding of the differences in yields when comparing the MSC to the SC. The PAM and the SC agreed within measurement uncertainties in terms of yields and composition for the systems and conditions studied here and this agreement supports the continued use of the PAM to study atmospheric aging.http://www.atmos-meas-tech.net/8/2315/2015/amt-8-2315-2015.pdf |
| spellingShingle | E. A. Bruns I. El Haddad A. Keller F. Klein N. K. Kumar S. M. Pieber J. C. Corbin J. G. Slowik W. H. Brune U. Baltensperger A. S. H. Prévôt Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition Atmospheric Measurement Techniques |
| title | Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| title_full | Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| title_fullStr | Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| title_full_unstemmed | Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| title_short | Inter-comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| title_sort | inter comparison of laboratory smog chamber and flow reactor systems on organic aerosol yield and composition |
| url | http://www.atmos-meas-tech.net/8/2315/2015/amt-8-2315-2015.pdf |
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