Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

IF value: 5.414
IF 5-year value: 5.958
IF 5-year
CiteScore value: 9.7
SNIP value: 1.517
IPP value: 5.61
SJR value: 2.601
Scimago H <br class='widget-line-break'>index value: 191
Scimago H
h5-index value: 89
Volume 11, issue 7
Atmos. Chem. Phys., 11, 3107–3118, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: The Border Air Quality and Meteorology Study (BAQS-Met)

Atmos. Chem. Phys., 11, 3107–3118, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 04 Apr 2011

Research article | 04 Apr 2011

Impact of model grid spacing on regional- and urban- scale air quality predictions of organic aerosol

C. A. Stroud1, P. A. Makar1, M. D. Moran1, W. Gong1, S. Gong1, J. Zhang1, K. Hayden1, C. Mihele1, J. R. Brook1, J. P. D. Abbatt2, and J. G. Slowik2,* C. A. Stroud et al.
  • 1Air Quality Research Division, Environment Canada, Toronto, Canada
  • 2Department of Chemistry, University of Toronto, Toronto, Canada
  • *now at: Paul Scherrer Institut, Villigen, Switzerland

Abstract. 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.

Publications Copernicus
Final-revised paper