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Improving Simulations of Fine Dust Surface Concentrations Over The Western United States By Optimizing The Particle Size Distribution


To improve estimates of remote contributions of dust to fine particulate matter (PM2.5) in the western United States, new dust particle size distributions (PSDs) based upon scale-invariant fragmentation theory (Kok_PSD) with constraints from in situ measurements (IMP_PSD) are implemented in a chemical transport model (GEOS-Chem). Compared to initial simulations, this leads to reductions in the mass of emitted dust particles with radii <1.8?µm by 40%–60%. Consequently, the root-mean-square error in simulated fine dust concentrations compared to springtime surface observations in the western United States is reduced by 67%–81%. The ratio of simulated fine to coarse PM mass is also improved, which is not achievable by reductions in total dust emissions. The IMP_PSD best represents the PSD of dust transported from remote sources and reduces modeled PM2.5 concentrations up to 5?µg/m3 over the western United States, which is important when considering sources contributing to nonattainment of air quality standards.

Article / Publication Data
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Accepted On
May 27, 2013
Fiscal Year
Publication Name
Geophysical Research Letters
Published On
June 01, 2013
Print Volume
Print Number
Page Range
Submitted On
March 21, 2013


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