AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Evaluating Regional Air Quality Model Impacts during the 2013 Rim Fire
MATTHEW WOODY, Kirk Baker, Benjamin Murphy, Jose-Luis Jimenez, Pedro Campuzano-Jost, United States Environmental Protection Agency
Abstract Number: 195 Working Group: Regional and Global Air Quality and Climate Modeling
Abstract Wildland fires are one of the largest sources of PM2.5 emissions in the U.S. and adversely impact air quality, human health, and visibility. Anthropogenic emissions have trended down in recent years and as that trend continues, the relative importance of wildland fires on air quality will continue to rise. However, the skill in photochemical models (e.g. the Community Multiscale Air Quality (CMAQ) model) to predict air quality impacts from wildland fires remains somewhat uncertain. In this work, we characterize CMAQ wildland fire performance by evaluating predictions for the 2013 Rim Fire, the third largest wildfire in California history, against gas and particle-phase measurements collected onboard NASA’s DC-8 aircraft during the SEAC4RS field campaign.
Results suggest that CMAQ captures the fire’s plume location and CO concentrations well. However, CMAQ significantly under-predicts the PM2.5 concentrations, the majority of which is comprised of organic aerosols (OA), in the vicinity of the fire by up to a factor of 8, likely a result of underrepresented emissions. While the traditional non-volatile primary organic aerosol treatment in CMAQ limits the underestimate of OA emissions and PM concentrations, the recently implemented semivolatile primary organic aerosol treatment more accurately captures the organic aerosol evolution of PM in the plume as it moves downwind of the fire. Finally, results suggest the need for biomass burning-specific model OA species and treatment, including aging, to better represent biomass burning PM in regional air quality models.