Spatially resolved photochemistry impacts emissions estimates in fresh wildfire plumes
Document Type: Journal Article
Author(s): Brett B. Palm; Qiaoyun Peng; Samuel R. Hall; Kirk Ullmann; Teresa L. Campos; Andrew J. Weinheimer; Denise D. Montzka; Geoffrey S. Tyndall; Wade Permar; Lu Hu; Frank Flocke; Emily V. Fischer; Joel A. Thornton
Publication Year: 2021

Cataloging Information

  • air quality
  • biomass burning
  • chemistry
  • fire plume evolution
  • hydroxyl radical
  • O3 - ozone
  • plume
  • wildfire
Record Maintained By:
Record Last Modified: November 22, 2021
FRAMES Record Number: 64771


Wildfire emissions affect downwind air quality and human health. Predictions of these impacts using models are limited by uncertainties in emissions and chemical evolution of smoke plumes. Using high-time-resolution aircraft measurements, we illustrate spatial variations that can exist within a plume due to differences in the photochemical environment. Horizontal and vertical crosswind gradients of dilution-corrected mixing ratios were observed in midday plumes for reactive compounds and their oxidation products, such as nitrous acid, catechol, and ozone, likely due to faster photochemistry in optically-thinner plume edges relative to darker plume cores. Gradients in plumes emitted close to sunset are characterized by titration of O3 in the plume and reduced or no gradient formation. We show how crosswind gradients can lead to underestimated emission ratios for reactive compounds and overestimated emission ratios for oxidation products. These observations will lead to improved predictions of wildfire emissions, evolution, and impacts across daytime and nighttime.

Online Link(s):
Palm, Brett B.; Peng, Qiaoyun; Hall, Samuel R.; Ullmann, Kirk; Campos, Teresa L.; Weinheimer, Andrew; Montzka, Deedee; Tyndall, Geoffrey; Permar, Wade; Hu, Lu; Flocke, Frank; Fischer, Emily V.; Thornton, Joel A. 2021. Spatially resolved photochemistry impacts emissions estimates in fresh wildfire plumes. Geophysical Research Letters online early.