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| Titel |
Impact of model grid spacing on regional- and urban- scale air quality predictions of organic aerosol |
| VerfasserIn |
C. A. Stroud, P. A. Makar, M. D. Moran, W. Gong, S. Gong, J. Zhang, K. Hayden, C. Mihele, J. R. Brook, J. P. D. Abbatt, J. G. Slowik |
| 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 ; 11, no. 7 ; Nr. 11, no. 7 (2011-04-04), S.3107-3118 |
| Datensatznummer |
250009582
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| Publikation (Nr.) |
 copernicus.org/acp-11-3107-2011.pdf |
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| Zusammenfassung |
| Regional-scale chemical transport model predictions of urban organic aerosol
to date tend to be biased low relative to observations, a limitation with
important implications for applying such models to human exposure health
studies. We used a nested version of Environment Canada's AURAMS model
(42- to- 15- to- 2.5-km nested grid spacing) to predict organic aerosol
concentrations for a temporal and spatial domain corresponding to the Border
Air Quality and Meteorology Study (BAQS-Met), an air-quality field study
that took place in the southern Great Lakes region in the summer of 2007.
The use of three different horizontal grid spacings allowed the influence of
this parameter to be examined. A domain-wide average for the 2.5-km domain
and a matching 15-km subdomain yielded very similar organic aerosol averages
(4.8 vs. 4.3 μg m−3, respectively). On regional scales, secondary
organic aerosol dominated the organic aerosol composition and was adequately
resolved by the 15-km model simulation. However, the shape of the organic
aerosol concentration histogram for the Windsor urban station improved for
the 2.5-km simulation relative to those from the 42- and 15-km simulations.
The model histograms for the Bear Creek and Harrow rural stations were also
improved in the high concentration "tail" region. As well the
highest-resolution model results captured the midday 4 July organic-aerosol
plume at Bear Creek with very good temporal correlation. These results
suggest that accurate simulation of urban and large industrial plumes in the
Great Lakes region requires the use of a high-resolution model in order to
represent urban primary organic aerosol emissions, urban VOC emissions, and
the secondary organic aerosol production rates properly. The positive
feedback between the secondary organic aerosol production rate and existing
organic mass concentration is also represented more accurately with the
highest-resolution model. Not being able to capture these finer-scale
features may partly explain the consistent negative bias reported in the
literature when urban-scale organic aerosol evaluations are made using
coarser-scale chemical transport models. |
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