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@ARTICLE{Decker:904139,
author = {Decker, Zachary C. J. and Robinson, Michael A. and
Barsanti, Kelley C. and Bourgeois, Ilann and Coggon, Matthew
M. and DiGangi, Joshua P. and Diskin, Glenn S. and Flocke,
Frank M. and Franchin, Alessandro and Fredrickson, Carley D.
and Gkatzelis, Georgios and Hall, Samuel R. and Halliday,
Hannah and Holmes, Christopher D. and Huey, L. Gregory and
Lee, Young Ro and Lindaas, Jakob and Middlebrook, Ann M. and
Montzka, Denise D. and Moore, Richard and Neuman, J. Andrew
and Nowak, John B. and Palm, Brett B. and Peischl, Jeff and
Piel, Felix and Rickly, Pamela S. and Rollins, Andrew W. and
Ryerson, Thomas B. and Schwantes, Rebecca H. and Sekimoto,
Kanako and Thornhill, Lee and Thornton, Joel A. and Tyndall,
Geoffrey S. and Ullmann, Kirk and Van Rooy, Paul and Veres,
Patrick R. and Warneke, Carsten and Washenfelder, Rebecca A.
and Weinheimer, Andrew J. and Wiggins, Elizabeth and
Winstead, Edward and Wisthaler, Armin and Womack, Caroline
and Brown, Steven S.},
title = {{N}ighttime and daytime dark oxidation chemistry in
wildfire plumes: an observation and model analysis of
{FIREX}-{AQ} aircraft data},
journal = {Atmospheric chemistry and physics},
volume = {21},
number = {21},
issn = {1680-7316},
address = {Katlenburg-Lindau},
publisher = {EGU},
reportid = {FZJ-2021-05709},
pages = {16293 - 16317},
year = {2021},
abstract = {Wildfires are increasing in size across the western US,
leading to increases in human smoke exposure and associated
negative health impacts. The impact of biomass burning (BB)
smoke, including wildfires, on regional air quality depends
on emissions, transport, and chemistry, including oxidation
of emitted BB volatile organic compounds (BBVOCs) by the
hydroxyl radical (OH), nitrate radical (NO3), and ozone
(O3). During the daytime, when light penetrates the plumes,
BBVOCs are oxidized mainly by O3 and OH. In contrast, at
night or in optically dense plumes, BBVOCs are oxidized
mainly by O3 and NO3. This work focuses on the transition
between daytime and nighttime oxidation, which has
significant implications for the formation of secondary
pollutants and loss of nitrogen oxides (NOx=NO+NO2) and has
been understudied. We present wildfire plume observations
made during FIREX-AQ (Fire Influence on Regional to Global
Environments and Air Quality), a field campaign involving
multiple aircraft, ground, satellite, and mobile platforms
that took place in the United States in the summer of 2019
to study both wildfire and agricultural burning emissions
and atmospheric chemistry. We use observations from two
research aircraft, the NASA DC-8 and the NOAA Twin Otter,
with a detailed chemical box model, including updated
phenolic mechanisms, to analyze smoke sampled during midday,
sunset, and nighttime. Aircraft observations suggest a range
of NO3 production rates (0.1–1.5 ppbv h−1) in plumes
transported during both midday and after dark. Modeled
initial instantaneous reactivity toward BBVOCs for NO3, OH,
and O3 is $80.1 \%,$ $87.7 \%,$ and $99.6 \%,$
respectively. Initial NO3 reactivity is 10–104 times
greater than typical values in forested or urban
environments, and reactions with BBVOCs account for
$>97 \%$ of NO3 loss in sunlit plumes (jNO2 up to
4×10−3s−1), while conventional photochemical NO3 loss
through reaction with NO and photolysis are minor pathways.
Alkenes and furans are mostly oxidized by OH and O3
$(11 \%–43 \%,$ $54 \%–88 \%$ for alkenes;
$18 \%–55 \%,$ $39 \%–76 \%,$ for furans,
respectively), but phenolic oxidation is split between NO3,
O3, and OH $(26 \%–52 \%,$ $22 \%–43 \%,$
$16 \%–33 \%,$ respectively). Nitrate radical
oxidation accounts for $26 \%–52 \%$ of phenolic
chemical loss in sunset plumes and in an optically thick
plume. Nitrocatechol yields varied between $33 \%$ and
$45 \%,$ and NO3 chemistry in BB plumes emitted late in
the day is responsible for $72 \%–92 \%$ $(84 \%$ in
an optically thick midday plume) of nitrocatechol formation
and controls nitrophenolic formation overall. As a result,
overnight nitrophenolic formation pathways account for
$56 \%±2 \%$ of NOx loss by sunrise the following day.
In all but one overnight plume we modeled, there was
remaining NOx $(13 \%–57 \%)$ and BBVOCs
$(8 \%–72 \%)$ at sunrise.},
cin = {IEK-8},
ddc = {550},
cid = {I:(DE-Juel1)IEK-8-20101013},
pnm = {2111 - Air Quality (POF4-211)},
pid = {G:(DE-HGF)POF4-2111},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000716444700001},
doi = {10.5194/acp-21-16293-2021},
url = {https://juser.fz-juelich.de/record/904139},
}