Journal of Geophysical Research Atmospheres,
Год журнала:
2024,
Номер
129(17)
Опубликована: Авг. 28, 2024
Abstract
Nighttime
oxidation
of
monoterpenes
(MT)
via
the
nitrate
radical
(NO
3
)
and
ozone
(O
contributes
to
formation
secondary
organic
aerosol
(SOA).
This
study
uses
observations
in
Atlanta,
Georgia
from
2011
2022
quantify
trends
nighttime
production
NO
(PNO
O
concentrations
compare
model
outputs
EPA's
Air
QUAlity
TimE
Series
Project
(EQUATES).
We
present
urban‐suburban
gradients
their
fractional
importance
(F)
for
MT
oxidation.
Both
EQUATES
show
a
decline
PNO
,
with
modeled
declining
faster
than
observations.
Despite
decreasing
we
find
that
continues
dominate
nocturnal
boundary
layer
(NBL)
(F
NO3
=
60%)
2017,
2021,
2022,
which
is
consistent
80%)
2013
2019.
contrasts
an
anticipated
F
based
on
prior
residual
layer,
where
dominant
oxidant.
Using
two
case
studies
heatwaves
summer
extreme
heat
events
can
increase
leading
short
lifetimes
(<1
hr)
high
gas‐phase
production.
Regardless
presence
heatwaves,
our
findings
suggest
sustained
urban
SE
US
under
x
emissions,
highlight
need
improved
representation
chemistry‐transport
models
additional
along
rural
gradients.
Environmental Science Atmospheres,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 1, 2025
Photodegradation
alters
secondary
organic
aerosol
(SOA)
chemical
composition
and
physical
properties,
promoting
the
formation
of
oxidation
products
in
both
gas-
particle-phase
by
depleting
high-molecular-weights
species
within
SOA.
Environmental Science & Technology,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 16, 2025
While
biomass
burning
(BB)
is
the
largest
source
of
fine
particles
in
atmosphere,
influence
relative
humidity
(RH)
and
photochemistry
on
BB
secondary
organic
aerosol
(BB-SOA)
formation
aging
remains
poorly
constrained.
These
effects
need
to
be
addressed
better
capture
comprehend
evolution
BB-SOA
atmosphere.
Cresol
(C7H8O)
used
as
a
proxy
investigate
these
effects.
It
emitted
directly
from
has
been
identified
significant
SOA
precursor
residential
wood-burning
emissions.
The
gas-
particle-phase
signal
intensities
are
investigated
using
online
mass
spectrometers.
An
increase
yield
7%
observed
when
RH
rises
0.5–20
70–87%.
At
elevated
RH,
nitrogen-containing
compounds
due
processes.
This
linked
net
decrease
viscosity,
enabling
formed
greater
extent
at
presence
nitrogen
oxides.
results
highlight
importance
particle
water
content
for
molecular
compounds.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(4), С. 2707 - 2724
Опубликована: Март 3, 2025
Abstract.
Solid
fuel
(SF)
combustions,
including
coal
and
biomass,
are
important
sources
of
pollutants
in
the
particle
gas
phase
therefore
have
significant
implications
for
air
quality,
climate,
human
health.
In
this
study,
we
systematically
examined
gas-phase
emissions,
using
Vocus
proton-transfer-reaction
time-of-flight
(PTR-TOF)
mass
spectrometer,
from
a
variety
solid
fuels,
beech
logs,
spruce/pine
branches
needles,
straw,
cow
dung,
coal.
The
average
emission
factors
(EFs)
organic
vapors
ranged
4.8
to
74.2
g
kg−1,
depending
on
combustion
phases
types.
Despite
slight
differences
modified
efficiency
(MCE)
some
experiments,
increasing
EFs
were
observed
with
lower
MCE.
relative
contribution
different
classes
showed
large
similarities
between
logs
stove
burning,
change
observed.
CxHyOz
family
is
most
abundant
group
vapor
emitted
all
SF
combustion.
However,
among
these
greater
nitrogen-containing
species
CxHy
families
(related
polycyclic
aromatic
hydrocarbons)
dung
burning
respectively.
Intermediate-volatility
compounds
(IVOCs)
constituted
fraction
emissions
combustion,
ranging
12.6
%
39.3
%.
This
was
particularly
notable
needles
(39.3
%)
(31.1
%).
Using
Mann–Whitney
U
test
studied
identified
specific
potential
new
markers
fuels
based
measurements.
product
pyrolysis
coniferyl-type
lignin
extract
cedar
pine
needle
as
open
(e.g.,
C10H14O2,
C11H14O2,
C10H10O2).
(C9H12O)
marker
log
burning.
Many
series
homologues
C10H11–21NO,
C12H11–21N,
C11H11–23NO,
C15H15–31N)
acetonitrile,
acrylonitrile,
propanenitrile,
methylpentanenitrile)
specifically
emissions.
Polycyclic
hydrocarbons
(PAHs)
9–12
carbons
significantly
higher
abundance
compared
other
fuels.
composition
reflects
burned
types
can
help
constrain
regional
models.
Mass Spectrometry Reviews,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 19, 2025
ABSTRACT
In
the
1980s,
researchers
discovered
remarkable
ability
of
electrospray
plumes
to
effectively
ionize
gas‐phase
molecules
via
secondary
ionization.
Around
20
years
later—coinciding
with
ambient
mass
spectrometry
revolution—secondary
ionization
(SESI)
and
extractive
(EESI)
coupled
were
revisited
further
developed
analyze
complex
mixtures
gas
aerosol
samples
in
real‐time
yet
high
sensitivity.
During
past
two
decades,
these
spectrometric
techniques
have
been
applied
across
a
broad
range
applications,
such
as
detection
illicit
drugs,
environmental
analysis,
series
metabolomic
studies
through
analysis
volatiles
emitted
from
living
organisms.
This
review
offers
comprehensive
overview
progress
SESI
EESI
applications
since
their
emergence.
Finally,
we
discuss
opportunities,
challenges,
along
future
directions
techniques.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(10), С. 5215 - 5231
Опубликована: Май 21, 2025
Abstract.
Styrene
is
emitted
by
anthropogenic
sources
and
biomass
burning
highly
reactive
towards
atmospheric
oxidants.
While
it
has
the
highest
nitrate
radical
(NO3)
reactivity
among
aromatic
hydrocarbons,
NO3
oxidation
of
styrene
formation
mechanisms
secondary
organic
aerosols
(SOA)
have
not
been
investigated.
In
this
study,
we
conduct
chamber
experiments
with
concentrations
ranging
from
9.5
to
155.2
ppb.
The
resulting
SOA
yields
range
14.0
%
22.1
aerosol
mass
loadings
5.9–147.6
µg
m−3
after
wall
loss
corrections.
chemical
composition
characterized
online
measurements,
revealing
that
dimeric
nitrates
(ONs)
constitute
90.9
total
signal
particle-phase
products.
C16H16N2O8
C8H9NO4
are
identified
as
major
products,
which
88.3
4.1
%,
respectively,
measured
signal.
We
propose
for
ON
including
common
RO2+
RO2
/
HO2
pathway
other
chain
termination
reactions
such
RO
+
R
R.
also
investigate
hydrolysis
particulate
ONs.
lifetime
ONs
determined
be
less
than
30
min.
This
short
can
attributed
stabilization
carbocation
delocalized
π
orbitals
benzene-related
skeleton
work
provides
first
fundamental
laboratory
data
evaluate
production
chemistry.
Additionally,
reported
time,
highlighting
compounds
previously
nitroaromatics
in
ambient
field
campaigns
could
Journal of Geophysical Research Atmospheres,
Год журнала:
2025,
Номер
130(11)
Опубликована: Июнь 3, 2025
Abstract
This
study
investigates
primary
emissions
and
photochemical
aging
evolution
mechanisms
of
PM
2.5
Nitroaromatic
compounds
(NACs)
released
from
solid
fuels
through
conducting
field
combustion
experiments.
The
emission
factors
(EFs)
NACs
are
much
higher
biomass
burning
(BB)
than
coal
(CC).
EFs
measured
species
mostly
increased
during
the
process
except
some
in
CC.
Photochemical
significantly
enhanced
absorbance
∑NACs,
but
different
between
BB
In
BB,
increasing
production
4‐nitrocatechol
(4NC),
4‐nitroguaiacol
(4NG),
4‐methyl‐5‐nitrocatechol
(4M5NC)
nitrogen
addition
reactions
light
absorption.
CC,
4NC
4‐methyl‐2,6‐dinitrophenol
as
well
indirect
photolysis
4NG
4M5NC
with
·OH
to
form
organic
intermediates
both
increase
Furthermore,
oxidation
potential
substantially
auto‐biotoxicity
generation
facilitating
1
O
2
decomposing
into
nitro‐quinones
