10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Regional-scale Impacts of Primary Ultrafine Particle Emissions in the United States
BENJAMIN MURPHY, Francis Binkowski, Ekbordin Winijkul, Matthew Alvarado, United States Environmental Protection Agency
Abstract Number: 1199 Working Group: Aerosol Modeling
Abstract Direct particle emissions substantially increase ultrafine particle (UFP) concentrations near emission sources and have impacts on aerosol properties like bulk surface area. However, standard emission inventories like the National Emission Inventory (NEI) report only bulk coarse and fine particle mass emission factors and so most chemical transport models do not explicitly account for the impacts of the large magnitude of UFP number emissions. This gap has important implications for understanding and managing air quality in the U.S. with respect to particulate pollution.
We have updated the Community Multiscale Air Quality (CMAQ) model with new algorithms and data to investigate the contributions of specific emissions sectors to UFP concentrations throughout the US. This research version of the model, called CMAQ-UFP, includes improved parameterizations of aerosol emissions from a single-distribution approach to a rich dataset of multiple distributions with dependencies on emission source, technology, and fuel. The new model gives a more complete representation of the complexity of UFP sources, sinks, and potential impacts.
We apply the new model to specific observations made throughout the U.S. including California and the mountain west. This combination of sites allows us to evaluate the model against detailed in situ and remotely-sensed particle properties. It further allows us to characterize the model in urban/suburban regimes with dramatically varying contributions from individual sources. Finally, we use this platform to quantify the spatio-temporal variation in the contribution of primary/secondary sources to particle number and surface area, two metrics thought to be important for connecting particulate pollution to human health impacts. This exercise improves our understanding of the most effective ways to mitigate the highest UFP concentrations in the US.