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Understanding the evolution of reactive organic carbon in wildfire plumes (CMAS 2023).
Citation:
Pye, H., L. Xu, B. Henderson, D. Pagonis, P. Campuzano-Jost, J. Jimenez, C. Allen, T. Skipper, F. Wiser, V. McNeill, B. Murphy, E. D'Ambro, P. Wennberg, E. Apel, D. Blake, M. Coggon, J. Gilman, T. Hanisco, G. Huey, J. Peischl, J. St. Clair, C. Warneke, G. Wolfe, AND C. Womack. Understanding the evolution of reactive organic carbon in wildfire plumes (CMAS 2023). CMAS Conference, Chapel Hill, NC, October 16 - 18, 2023.
Impact/Purpose:
This work will result in an improved representation of wildland fires in CMAQ-CRACMM. Since wildland fires contribute to ozone, particulate matter, and hazardous air pollutants, this information will improve the representation of risk in future AirToxScreen and other CMAQ applications.
Description:
Wildfires are an increasingly prominent source of emissions to air including particulate matter and hazardous air pollutants. Understanding the health implications of wildfire smoke is complicated by the fact that the composition of smoke emissions as well as their transformation products are incompletely characterized. In this work, we aim to build a relatively complete description of reactive organic carbon (ROC) emissions and their secondary products in wildland fires using a combination of observations and model predictions. Specifically, we gather observations from the DC-8 aircraft for western U.S. wildfires during the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field campaign and compare to predictions from the Community Multiscale Air Quality (CMAQ) model. Within CMAQ, we use the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) with AMORE isoprene chemistry which has expanded secondary organic aerosol precursors including phenols, cresols, furans, semivolatile organic compounds, and intermediate volatility organic compounds relevant for wildland fires. We find the base model captures 77 % by mole of measured gas-phase ROC emissions. However, underestimates in emissions result in organic aerosol being underestimated by a factor of 6 near the source. After updating the emission inputs and chemical evolution of wildfire smoke, species concentrations will be extended to cancer and non-cancer estimates of toxicity.