Abstract.
Secondary
organic
aerosol
(SOA)
plays
an
important
role
in
particulate
air
pollution,
but
its
formation
mechanism
is
still
not
fully
understood.
The
chemical
composition
of
non-refractory
matter
with
a
diameter
≤2.5
class="inline-formula">µm
(NR-PM2.5),
OA
sources,
and
SOA
mechanisms
were
investigated
urban
Xi'an
during
winter
2018.
fractional
contribution
to
total
mass
(58
%)
was
larger
than
primary
(POA,
42
%).
Biomass-burning-influenced
oxygenated
(OOA-BB)
resolved
formed
from
the
photochemical
oxidation
aging
biomass
burning
(BBOA).
OOA-BB
more
favorable
on
days
fraction
higher
BBOA
concentration.
In
comparison,
aqueous-phase
processed
(aq-OOA)
dependent
secondary
inorganic
(SIA)
content
liquid
water
(ALWC),
it
showed
large
increase
(to
50
%
OA)
SIA-enhanced
periods.
Further
van
Krevelen
(VK)
diagram
analysis
suggests
that
addition
carboxylic
acid
groups
fragmentation
dominated
reference
days,
while
increased
aq-OOA
contributions
periods
likely
reflect
evolution
due
alcohol
or
peroxide
groups.
ACS Earth and Space Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 12, 2025
Excited
triplet
states
of
organic
molecules
(3C*)
present
in
aerosols
have
been
investigated
for
their
ability
as
oxidants
the
aqueous
phase.
Aerosols
were
collected
Grenoble
(France),
winter
and
summer
times
during
period
December
2021
through
June
2022,
steady-state
concentrations
quantum
yields
3C*,
1O2,
•OH
determined
under
solar-simulated
conditions
using
various
specific
chemical
probes.
For
comparison
purposes,
these
three
at
sample
10
mg
C
L–1.
The
resulting
all
larger
samples
than
ones
ranked
follows
[1O2]ss
>
[3C*]ss
[OH]ss
agreement
with
previous
reports.
However,
those
do
exhibit
different
reactivities
classes
compounds,
which
can
be
a
generic
way
kOH,ORG
k3C*,ORG
k1O2,ORG.
If
we
combine
reactivity
oxidants,
it
appears
that
matter
are
main
most
compounds.
This
study
emphasizes
relevance
excited
compared
to
singlet
oxygen
OH
radicals
need
additional
studies
conditions.
Atmospheric chemistry and physics,
Journal Year:
2023,
Volume and Issue:
23(2), P. 963 - 979
Published: Jan. 20, 2023
Abstract.
Water-soluble
humic-like
substances
(HULIS)
absorb
light
in
near-UV
and
visible
wavelengths
exert
significant
influence
on
the
atmospheric
environment
climate.
However,
knowledge
HULIS
evolution
during
haze
bloom-decay
process
is
limited.
Herein,
PM2.5
samples
were
obtained
a
winter
event
Guangzhou,
China,
absorption
molecular
composition
of
investigated
by
UV–Vis
spectrophotometry
ultrahigh-resolution
mass
spectrometry.
Compared
with
clean
days,
coefficients
(Abs365)
days
significantly
higher
but
efficiencies
(MAE365)
relatively
low,
suggesting
diverse
dynamic
properties
episodes.
The
CHO
CHON
compounds
most
abundant
components
HULIS,
followed
CHOS,
CHONS,
CHN.
Haze
presented
comparatively
high
weight;
lower
aromaticity
index
(AImod);
O/Cw,
O/Nw,
O/Sw
ratios,
indicating
that
fractions
undergo
oxidation
compared
to
days.
Moreover,
AImod
major
potential
chromophores
contributed
absorption.
It
worth
noting
proportions
these
decreased
events,
mainly
owing
their
Besides,
accumulated
contribution
organic
emitted
from
vehicles
formed
reactions
biogenic
volatile
(bio-VOCs)
also
diluted
light-absorbing
HULIS.
These
findings
help
us
understand
processes
subtropic
region
China.
Atmospheric chemistry and physics,
Journal Year:
2022,
Volume and Issue:
22(15), P. 10139 - 10153
Published: Aug. 9, 2022
Abstract.
Secondary
organic
aerosol
(SOA)
plays
an
important
role
in
particulate
air
pollution,
but
its
formation
mechanism
is
still
not
fully
understood.
The
chemical
composition
of
non-refractory
matter
with
a
diameter
≤2.5
µm
(NR-PM2.5),
OA
sources,
and
SOA
mechanisms
were
investigated
urban
Xi'an
during
winter
2018.
fractional
contribution
to
total
mass
(58
%)
was
larger
than
primary
(POA,
42
%).
Biomass-burning-influenced
oxygenated
(OOA-BB)
resolved
formed
from
the
photochemical
oxidation
aging
biomass
burning
(BBOA).
OOA-BB
more
favorable
on
days
fraction
higher
BBOA
concentration.
In
comparison,
aqueous-phase
processed
(aq-OOA)
dependent
secondary
inorganic
(SIA)
content
liquid
water
(ALWC),
it
showed
large
increase
(to
50
%
OA)
SIA-enhanced
periods.
Further
van
Krevelen
(VK)
diagram
analysis
suggests
that
addition
carboxylic
acid
groups
fragmentation
dominated
reference
days,
while
increased
aq-OOA
contributions
periods
likely
reflect
evolution
due
alcohol
or
peroxide
groups.
Environmental Science & Technology,
Journal Year:
2024,
Volume and Issue:
58(46), P. 20588 - 20597
Published: Nov. 7, 2024
The
linkages
between
BrC
optical
properties
and
chemical
composition
remain
inadequately
understood,
with
quantified
chromophores
explaining
less
than
25%
of
ambient
aerosol
light
absorption.
This
study
characterized
38
typical
in
aerosols
collected
Xi'an,
absorption
contributions
to
ranging
from
1.6
±
0.3
5.8
2.6%
at
365
nm.
Based
on
these
chromophores,
an
interpretable
machine
learning
model
the
Shapley
Additive
Explanation
(SHAP)
method
were
employed
explore
relationships
composition.
attained
high
accuracy
Pearson
correlation
coefficients
(
Abstract
This
study
characterizes
vehicular
PAHs
using
roadway
tunnel
measurements
on
Mumbai-Pune
Expressway,
a
crucial
route
in
Western
India.
Dominated
by
four-
to
six-ring
(75%-89%),
concentrations
were
influenced
diesel,
heavy-duty
vehicles
(HDVs),
and
super-emitters.
The
total
PAH
emission
factor
was
52.7(±4.5)
μg
veh⁻¹
km⁻¹.
An
inverse
relationship
observed
between
molecular
weight
volatility
of
organic
carbon
(OC).
Molecular
also
strongly
correlated
with
mass
absorption
coefficient
(MAC)
brown
(BrC),
significantly
enhancing
light
absorption.
Methanol-soluble
BrC
exhibited
stronger
correlation
higher
(ΣHMW
).
Carcinogenic
accounted
for
98.9%
toxicity,
incremental
lifetime
cancer
risk
(ILCR)
values
~5
~2
per
million
adults
children,
respectively.
These
findings
highlight
the
significant
contribution
emissions
urban
air
quality
health
risks,
emphasizing
urgent
need
mitigation
strategies
while
providing
insights
improve
representation
climate
models.
