Atmospheric chemistry and physics,
Год журнала:
2024,
Номер
24(24), С. 14177 - 14190
Опубликована: Дек. 19, 2024
Abstract.
Secondary
organic
aerosols
(SOAs)
from
highly
volatile
compounds
(VOCs)
are
currently
not
well
represented
in
numerical
models
as
their
heterogeneous
formation
mechanisms
the
atmosphere
remain
unclear.
Based
on
smog
chamber
experiments,
here
we
investigated
yield
and
pathway
of
SOA
acetone
photochemical
reactions
under
low-NOx
conditions
presence
preexisting
haze
particles
((NH4)2SO4
NH4HSO4)
saline
mineral
(Na2SO4)
ammonia-rich
conditions.
Our
results
showed
that
acetone-derived
is
remarkably
enhanced
via
multiphase
these
seeds,
especially
for
particles.
We
found
aerosol
acidity
a
key
factor
controlling
pathways
SOA,
which
acids,
alcohol,
carbonyls
produced
dissolve
into
aqueous
phase
seeds
subsequently
esterify
and/or
oligomerize
SOAs
consist
larger
molecules
acidic
but
smaller
neutral
aerosols.
Moreover,
light
absorption
ability
formed
(NH4)2SO4
stronger
than
Na2SO4
particles,
ammonia,
due
to
N-containing
organics.
Through
comparison
with
methylglyoxal
(MGly),
total
2.8–8.2
times
irreversible
uptake
MGly,
suggesting
only
considering
MGly
precursor
will
probably
underestimate
role
global
production
since
abundantly
exists
troposphere.
Environment International,
Год журнала:
2025,
Номер
195, С. 109251 - 109251
Опубликована: Янв. 1, 2025
The
rapid
urbanization
in
China
has
brought
about
serious
air
pollution
problems,
which
are
likely
to
persist
for
a
considerable
period
as
the
process
continues.
In
urban
areas,
spatial
distribution
of
pollutants
represented
by
PM
Journal of Geophysical Research Atmospheres,
Год журнала:
2025,
Номер
130(3)
Опубликована: Фев. 6, 2025
Abstract
Brown
carbon
(BrC)
is
known
to
have
a
great
impact
on
atmospheric
radiative
forcing,
but
its
absorption
characteristics
at
the
molecular
level
not
well
understood.
This
study
investigated
seasonal
variations
of
light
and
composition
BrC
in
Xi'an,
China.
Results
showed
that
exhibited
higher
capacity
cold
(autumn
winter)
than
warm
seasons
(spring
summer).
Nitrogen‐containing
organic
compounds
were
identified
as
important
chromophores.
Oxidized‐N
originated
from
biomass
burning
emissions
NO
x
/NO
3
−
mediated
oxidation
reactions
predominant
seasons,
whereas
reduced‐N
mainly
formed
NH
/NH
4
+
abundant
seasons.
These
results
contribute
better
understanding
formation
mechanisms
nitrogen‐containing
chromophores
PM
2.5
.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(3), С. 1917 - 1930
Опубликована: Фев. 12, 2025
Abstract.
Brown
carbon
aerosol
(BrC)
is
a
major
contributor
to
atmospheric
air
pollution
in
Europe,
especially
winter.
Therefore,
we
studied
the
chemical
composition,
diurnal
variation,
and
sources
of
BrC
from
17
February
16
March
2021
at
rural
location
southwest
Germany.
In
total,
178
potential
molecules
(including
7
nitro
aromatic
compounds,
NACs)
were
identified
particle
phase
comprising
on
average
83
±
44
ng
m−3,
31
4
gas
contributing
8.5
6.7
m−3
during
whole
campaign.
The
light
absorption
seven
NACs
was
0.2
Mm−1,
2.2
2.1
%
total
370
nm.
addition,
variations
show
that
gas-phase
higher
daytime
lower
night.
It
mainly
controlled
by
secondary
formation
(e.g.
photooxidation)
particle-to-gas
partitioning.
Correspondingly,
particle-phase
Secondary
dominates
with
61
21
%,
while
39
originated
biomass
burning.
Furthermore,
showed
decreasing
due
photochemical
ageing.
This
study
extends
current
understanding
real-time
behaviours
brown
characteristic
central
Europe.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(5), С. 2763 - 2780
Опубликована: Март 4, 2025
Abstract.
Nitrogen-containing
organic
compounds
(NOCs)
impact
air
quality
and
human
health.
Here,
the
abundance,
potential
precursors,
main
formation
mechanisms
of
NOCs
in
PM2.5
during
winter
were
compared
for
first
time
among
Haerbin
(dependent
on
coal
heating),
Beijing
(natural
gas
as
heating
energy),
Hangzhou
(no
centralized
policy).
The
total
signal
intensity
CHON+,
CHN+,
CHON−
was
highest
lowest
Hangzhou.
Anthropogenic
aromatics
accounted
73
%–93
%
all
identified
precursors
Haerbin.
Although
abundance
aromatic-derived
lower
than
Haerbin,
also
contributors
to
NOC
Beijing.
exhibited
levels
aromatic
precursors.
Furthermore,
non-metric
multidimensional
scaling
analysis
indicated
an
overall
reduction
fossil
fuel
combustion
pollution
along
route
from
We
found
that
aqueous-phase
processes
(mainly
condensation,
hydrolysis,
or
dehydration
reduced
mainly
oxidization
hydrolysis
oxidized
NOCs)
can
promote
transformation
produce
NOCs,
leading
most
significant
increase
(particularly
haze
days).
Reduced
precursor
emissions
(the
lowest)
constrained
NOCs.
results
suggest
aerosol
coal-dependent
cities
is
controlled
by
anthropogenic
processes.
Thus,
without
effective
emission
controls,
through
may
still
pose
a
large
threat
quality.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(6), С. 3647 - 3667
Опубликована: Март 27, 2025
Abstract.
To
understand
the
spatial
variation
of
optical
and
structural
properties
water-soluble
brown
carbon
its
influencing
factors
in
China,
light
absorption,
fluorescence,
Fourier
transform
infrared
(FTIR)
spectrum
organic
(WSOC)
different
regions
China
are
measured
following
same
analytical
methods.
The
average
absorption
coefficients
mass
efficiencies
WSOC
at
365
nm
(Abs365
MAE365)
rank
from
high
to
low
as
northwest
>
southwest
north
east
regional
site,
with
higher
values
northern
than
southern
sites
inland
areas
coastal
areas.
resolved
by
spectra-based
positive
matrix
factorization
model
abundance
aromatic
O−H
C=C
functional
groups
determined
FTIR
both
indicate
that
compounds
significant
light-absorbing
substances
have
a
impact
on
fluorophores.
Multiple
linear
regression
analysis
shows
fluorophores
identified
fluorescence
spectra
combined
parallel
factor
(PARAFAC)
contribute
about
62
%–93
%
all
sites,
which
humic-like
substance
(HULIS)
contributes
most,
especially
highly
oxygenated
HULIS
(29
%–50
%)
long
emission
wavelengths.
Combustion
source
emissions
atmospheric
chemical
processes
impacts
some
sites.
Moreover,
relative
humidity
(RH)
can
also
affect
MAE365
WSOC,
decreasing
increase
RH
when
RH<60
remaining
relatively
unchanged
RH>60
%.
Taken
together,
this
study
promotes
better
understanding
heterogeneity
their
China.
Journal of Geophysical Research Atmospheres,
Год журнала:
2025,
Номер
130(11)
Опубликована: Май 28, 2025
Abstract
The
extensive
utilization
of
agricultural
machinery
in
China
has
made
it
a
prominent
contributor
to
particulate
matter
(PM).
However,
there
still
exist
significant
knowledge
gaps
understanding
optical
characteristics
and
molecular
composition
chromophores
brown
carbon
(BrC)
PM
emitted
from
machinery.
Therefore,
BrC
six
typical
machines
were
measured
investigate
the
light
absorption,
chromophore
characteristics,
influencing
factors.
Results
showed
that
average
emission
factors
methanol‐soluble
organic
(MSOC)
water‐soluble
(WSOC)
0.96
0.21
g
(kg
fuel)
−1
,
respectively,
exhibiting
clear
decreasing
trends
with
increasing
engine
power
improving
standards.
Despite
absorption
coefficient
methanol‐extracted
(Abs
365,M
)
being
approximately
2.2
times
higher
than
water
365,W
),
mass
efficiency
water‐extracted
(MAE
exhibited
significantly
greater
values
MAE
.
Among
detected
chromophores,
nitro‐aromatic
compounds
(NACs)
highest
contribution
was
about
14.5
more
total
compared
their
contributions
MSOC
(0.04%),
followed
by
polycyclic
aromatic
hydrocarbons
(PAHs)
oxygenated
PAHs
(OPAHs).
Besides,
integrated
simple
forcing
estimated
be
1.5
W
for
3.7
WSOC,
indicating
radiative
findings
this
study
not
only
provide
fundamental
data
climate
impact
estimation
but
also
propose
effective
strategies
mitigate
emissions,
such
as
enhancing
standards
promoting
adoption
high‐power
