Atmospheric chemistry and physics,
Год журнала:
2023,
Номер
23(23), С. 15077 - 15096
Опубликована: Дек. 7, 2023
Abstract.
Secondary
organic
aerosols
(SOAs)
formed
by
oxidation
of
typical
precursors
largely
emitted
biomass
burning,
such
as
polycyclic
aromatic
hydrocarbons
(PAHs)
and
furans,
are
still
poorly
characterized.
We
evaluated
compared
the
formation
yields,
effective
density
(ρeff),
absorption
Ångström
exponent
(α),
mass
coefficient
(MAC)
laboratory-generated
SOAs
from
three
furan
compounds
four
PAHs.
were
generated
in
an
flow
reactor
under
day-
(OH
radicals)
or
nighttime
(NO3
conditions.
The
ρeff,
α,
MAC
varied
depending
on
precursor
oxidant
considered.
ρeff
with
OH
NO3
tended
to
increase
particle
size
before
reaching
a
“plateau”,
highlighting
potential
differences
SOA
chemical
composition
and/or
morphology,
according
size.
Three
times
lower
yields
obtained
OH.
PAH
(18
%–76
%)
five
six
higher
than
those
for
furans
(3
%–12
%).
While
showed
low
negligible
light
properties,
had
significant
impact
UV–visible
region,
implying
contribution
atmospheric
brown
carbon.
No
values
was
observed
processes,
probably
due
nitrogen-containing
chromophores
only
(without
NOx).
results
demonstrated
that
PAHs
through
both,
have
substantial
aerosol
properties.
Chemical Society Reviews,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 1, 2025
The
light-absorbing
chemical
components
of
atmospheric
organic
aerosols
are
commonly
referred
to
as
Brown
Carbon
(BrC),
reflecting
the
characteristic
yellowish
brown
appearance
aerosol.
Environmental Science & Technology,
Год журнала:
2022,
Номер
56(8), С. 4816 - 4827
Опубликована: Апрель 6, 2022
Secondary
organic
aerosols
(SOAs)
affect
incoming
solar
radiation
by
interacting
with
light
at
ultraviolet
and
visible
wavelength
ranges.
However,
the
relationship
between
chemical
composition
optical
properties
of
SOA
is
still
not
well
understood.
In
this
study,
complex
refractive
index
(RI)
produced
from
OH
oxidation
naphthalene
in
presence
nitrogen
oxides
(NOx)
was
retrieved
online
range
315–650
nm
bulk
characterized
an
high-resolution
time-of-flight
mass
spectrometer.
addition,
molecular-level
brown
carbon
chromophores
determined
using
high-performance
liquid
chromatography
coupled
to
a
photodiode
array
detector
The
real
part
RI
increases
both
NOx/naphthalene
ratio
aging
time,
likely
due
increased
mean
polarizability
decreased
molecular
weight
fragmentation.
Highly
absorbing
nitroaromatics
(e.g.,
C6H5NO4,
C7H7NO4,
C7H5NO5,
C8H5NO5)
under
higher
NOx
conditions
contribute
significantly
absorption
SOA.
imaginary
linearly
NOx/VOCs
formation
nitroaromatic
compounds.
As
function
aging,
O/C
(slope
=
0.024),
mainly
attributed
achieved
ratio,
which
favors
light-absorbing
nitroaromatics.
enhancement
as
significant
extensive
it
lower
time
opening
aromatic
rings
reactions.
Environmental Science & Technology,
Год журнала:
2024,
Номер
58(2), С. 1236 - 1243
Опубликована: Янв. 3, 2024
Aqueous-phase
reactions
of
α-dicarbonyls
with
amines
or
ammonium
have
been
identified
as
important
sources
secondary
brown
carbon
(BrC).
However,
the
kinetics
BrC
formation
and
effects
pH
are
still
not
very
clear.
In
this
study,
by
aqueous
(glyoxal
methylglyoxal)
ammonium,
amino
acids,
alkylamines
in
bulk
solution
at
different
values
investigated.
Our
results
reveal
pH-parameterized
production
rate
constants,
kBrCII
(m–1
[M]−2
s–1),
based
on
light
absorption
between
300
500
nm:
log10(kBrCII)
=
(1.0
±
0.1)
×
–
(7.4
1.0)
for
glyoxal
(6.3
0.9)
methylglyoxal.
The
linear
slopes
closing
to
1.0
indicate
that
is
governed
nitrogen
nucleophilic
addition
pathway.
Consequently,
absorptivities
produced
increase
exponentially
pH.
from
methylglyoxal
higher
(≥6.5)
exhibits
optical
properties
comparable
biomass
burning
coal
combustion,
categorized
"weakly"
absorbing
BrC,
while
lower
(<6.0)
(pH
5.0–7.0)
falls
into
"very
weakly"
BrC.
pH-dependent
feature
significantly
affects
solar
ability
thus
atmospheric
photochemical
processes,
e.g.,
7.0
absorbs
14–16
times
more
power
compared
5.0,
which
turn
could
lead
a
decrease
1
order
magnitude
photolysis
constants
O3
NO2.
Environment International,
Год журнала:
2024,
Номер
187, С. 108724 - 108724
Опубликована: Май 1, 2024
The
mass
concentration
of
atmospheric
particulate
matter
(PM)
has
been
continuously
decreasing
in
the
Beijing-Tianjin-Hebei
region.
However,
health
endpoints
do
not
exhibit
a
linear
correlation
with
PM
concentrations.
Thus,
it
is
urgent
to
clarify
prior
toxicological
components
further
improve
air
quality.
In
this
study,
we
analyzed
long-term
oxidative
potential
(OP)
water-soluble
PM2.5,
which
generally
considered
more
effective
assessing
hazardous
exposure
Beijing
from
2018
2022
based
on
dithiothreitol
assay
and
identified
crucial
drivers
OP
PM2.5
online
monitoring
pollutants,
receptor
model,
random
forest
(RF)
model.
Our
results
indicate
that
dust,
traffic,
biomass
combustion
are
main
sources
Beijing.
complex
interactions
dust
particles,
black
carbon,
gaseous
pollutants
(nitrogen
dioxide
sulfur
dioxide)
factors
driving
evolution,
particular,
leading
abnormal
rise
2022.
data
shows
higher
observed
winter
spring
compared
summer
autumn.
diurnal
variation
characterized
by
declining
trend
0:00
14:00
an
increasing
23:00.
spatial
was
as
lower
than
Shijiazhuang,
while
Zhenjiang
Haikou,
primarily
influenced
distribution
carbon.
significance
identifying
key
influencing
provide
new
insights
for
advancing
quality
improvement
efforts
focus
safeguarding
human
Environmental Science & Technology,
Год журнала:
2024,
Номер
58(17), С. 7493 - 7504
Опубликована: Апрель 18, 2024
Samples
of
brown
carbon
(BrC)
material
were
collected
from
smoke
emissions
originating
wood
pyrolysis
experiments,
serving
as
a
proxy
for
BrC
representative
biomass
burning
emissions.
The
acquired
samples,
referred
to
"pyrolysis
oil
(PO
Environmental Science & Technology,
Год журнала:
2024,
Номер
unknown
Опубликована: Фев. 23, 2024
Sub-Saharan
Africa
is
a
hotspot
for
biomass
burning
(BB)-derived
carbonaceous
aerosols,
including
light-absorbing
organic
(brown)
carbon
(BrC).
However,
the
chemically
complex
nature
of
BrC
in
BB
aerosols
from
this
region
not
fully
understood.
We
generated
smoke
chamber
through
smoldering
combustion
common
sub-Saharan
African
fuels
(hardwoods,
cow
dung,
savanna
grass,
and
leaves).
quantified
aethalometer-based,
real-time
light-absorption
properties
BrC-containing
organic-rich
accounting
variations
wavelength,
fuel
type,
relative
humidity,
photochemical
aging
conditions.
In
filter
samples
collected
Botswana
winter,
we
identified
182
species,
classified
into
lignin
pyrolysis
products,
nitroaromatics,
coumarins,
stilbenes,
flavonoids.
Using
an
extensive
set
standards,
determined
species-specific
mass
emission
factors.
Our
analysis
revealed
linear
relationship
between
combined
species
contribution
to
chamber-measured
aerosol
(0.4–14%)
mass-absorption
cross-section
at
370
nm
(0.2–2.2
m2
g–1).
Hierarchical
clustering
resolved
key
molecular-level
components
matrix,
with
photochemically
aged
emissions
leaf
cow-dung
showing
fingerprints
similar
those
found
aerosols.
These
quantitative
findings
could
potentially
help
refine
climate
model
predictions,
aid
source
apportionment,
inform
effective
air
quality
management
policies
human
health
global
climate.
Environmental Science Atmospheres,
Год журнала:
2023,
Номер
3(6), С. 991 - 1007
Опубликована: Янв. 1, 2023
Relative
humidity,
NO
x
,
and
NH
3
can
all
alter
the
molecular,
optical,
hygroscopic
properties
of
naphthalene
SOAs,
with
a
complex
synergy
between
these
factors.
Environmental Science & Technology,
Год журнала:
2023,
Номер
57(48), С. 20085 - 20096
Опубликована: Ноя. 20, 2023
The
light
absorption
properties
of
brown
carbon
(BrC),
which
are
linked
to
molecular
chromophores,
may
play
a
significant
role
in
the
Earth's
energy
budget.
While
nitroaromatic
compounds
have
been
identified
as
strong
chromophores
wildfire-driven
BrC,
other
types
remain
be
investigated.
Given
electron-withdrawing
nature
carbonyls
ubiquitous
atmosphere,
we
characterized
carbonyl
BrC
samples
from
nighttime
oxidation
furan
and
pyrrole
derivatives,
important
but
understudied
precursors
secondary
organic
aerosols
primarily
found
wildfire
emissions.
Various
were
quantified
samples,
their
ultraviolet-visible
spectra
simulated
by
using
time-dependent
density
functional
theory.
Our
findings
suggest
that
with
bonded
nitrogen
(i.e.,
imides
amides)
derived
N-containing
heterocyclic
substantially
contribute
absorption.
contributed
over
40%
total
at
wavelengths
below
350
nm
above
430
BrC.
contributions
differed
significantly
wavelength,
highlighting
divergent
importance
different
wavelength
ranges.
Overall,
our
highlight
significance
underscore
need
for
further
investigation.
