AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Characterizing Primary Ultrafine Particle Sources in the United States with CMAQ-UF
BENJAMIN MURPHY, Francis Binkowski, Ekbordin Winijkul, Matthew Alvarado, United States Environmental Protection Agency
Abstract Number: 907 Working Group: Remote and Regional Atmospheric Aerosol
Abstract We have updated the Community Multiscale Air Quality (CMAQ) model v5.3 with new algorithms and data to represent the emission, secondary formation, and growth of ultrafine particles. This enhanced model, CMAQ-UF, is evaluated with measurements from several urban and rural sites throughout the US. We then analyze CMAQ results at the continental US level to determine the sensitivity of ultrafine particle exposure to important model parameters governing both primary and secondary introduction of new particles.
We have shown previously that organic compounds and amines can participate with sulfuric acid to form new particles or, when sulfuric acid concentrations are low, generating particles on their own. These processes are an important regional driver of ultrafine particle concentrations whereas primary emissions are the fundamental source for ultrafine particles in urban and industrialized areas. We have incorporated our robust algorithm for new particle formation and growth along with state-of-the-science parameterizations of the size distribution of primary particle emissions from more than 40 source classes (e.g. vehicles, natural gas operations, coal-fired power plants, wildfires, etc.) into a detailed annual simulation of ultrafine particle sources and fate in the United States.
We apply the new model to observations made throughout the US including California (the CalNex and CARES 2010 campaigns), and the Denver DISCOVER-AQ campaign. The qualities of these and other observation sites allow us to constrain the model in urban, suburban, and rural locations, which is critical since the drivers of ultrafine particle concentrations are expected to change dramatically among these receptor types. Characterization of ultrafine particle pollution with CMAQ-UF improves our understanding of the most effective ways to mitigate the highest concentrations in the US.