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| Titel |
Global modeling of SOA formation from dicarbonyls, epoxides, organic nitrates and peroxides |
| VerfasserIn |
G. Lin, J. E. Penner, S. Sillman, D. Taraborrelli, J. Lelieveld  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 10 ; Nr. 12, no. 10 (2012-05-31), S.4743-4774 |
| Datensatznummer |
250011178
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| Publikation (Nr.) |
 copernicus.org/acp-12-4743-2012.pdf |
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| Zusammenfassung |
| Recent experimental findings indicate that secondary organic aerosol (SOA)
represents an important and, under many circumstances, the major fraction of
the organic aerosol burden. Here, we use a global 3-D model (IMPACT) to test
the results of different mechanisms for the production of SOA. The basic
mechanism includes SOA formation from organic nitrates and peroxides
produced from an explicit chemical formulation, using partition coefficients
based on thermodynamic principles together with assumptions for the rate of
formation of low-volatility oligomers. We also include the formation of
low-volatility SOA from the reaction of glyoxal and methylglyoxal on aqueous
aerosols and cloud droplets as well as from the reaction of epoxides on
aqueous aerosols. A model simulation including these SOA formation
mechanisms gives an annual global SOA production of 120.5 Tg. The global
production of SOA is decreased substantially to 90.8 Tg yr−1 if the HOx
regeneration mechanism proposed by Peeters et al. (2009) is used. Model
predictions with and without this HOx (OH and HO2 regeneration scheme are compared
with multiple surface observation datasets, namely: the Interagency
Monitoring of Protected Visual Environments (IMPROVE) for the United States,
the European Monitoring and Evaluation Programme (EMEP), and aerosol mass
spectrometry (AMS) data measured in both the Northern Hemisphere and
tropical forest regions. All model simulations show reasonable agreement
with the organic carbon mass observed in the IMPROVE network and the AMS
dataset, however observations in Europe are significantly underestimated,
which may be caused by an underestimation of primary organic aerosol
emissions (POA) in winter and of emissions and/or SOA production in the
summer. The modeled organic aerosol concentrations tend to be higher by
roughly a factor of three when compared with measurements at three tropical
forest sites. This overestimate suggests that more measurements and model
studies are needed to examine the formation of organic aerosols in the
tropics. The modeled organic carbon (OC) in the free troposphere is in agreement with
measurements in the ITCT-2K4 aircraft campaign over North America and in
pollution layers off Asia during the INTEX-B campaign, although the model
underestimates OC in the free troposphere in comparison with the ACE-Asia
campaign off the coast of Japan. |
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