ACS Earth and Space Chemistry,
Journal Year:
2024,
Volume and Issue:
8(4), P. 788 - 797
Published: April 2, 2024
In
Northeast
Asia,
the
elevated
levels
of
fine
particulate
matter
(PM2.5)
are
an
environmental
concern,
yet
their
physicochemical
properties
have
been
poorly
characterized.
Herein,
we
determined
phase
states
PM2.5
in
92
filter
samples
collected
from
four
different
cities─Beijing,
Seoul,
Seosan,
and
Ulaanbaatar─during
2020–2022,
within
a
temperature
range
∼290–293
K.
We
noted
distinct
trend
boundary
relative
humidity
(RH)
liquid
semisolid
phases
these
samples.
As
inorganic
fraction
increased,
RH
decreased,
whereas
that
increased.
This
behavior
was
strongly
influenced
by
chemical
composition
PM2.5.
By
incorporating
ambient
data
each
city,
estimated
prevalent
planetary
layer
Asia.
Our
findings
revealed
dominant
urban
areas
were
semisolid.
Additionally,
showed
critical
threshold
based
on
aerosol
water
content
(ALWC)
PM2.5:
primarily
for
ALWC/PM2.5
ratios
≥∼0.5
predominantly
<∼0.5.
These
insights
could
contribute
to
better
understanding
mechanisms
underlying
pollution
Environmental Science & Technology,
Journal Year:
2021,
Volume and Issue:
55(8), P. 4227 - 4242
Published: March 24, 2021
Atmospheric
oxidation
of
sulfur
dioxide
(SO2)
forms
sulfate-containing
aerosol
particles
that
impact
air
quality,
climate,
and
human
ecosystem
health.
It
is
well-known
in-cloud
SO2
frequently
dominates
over
gas-phase
on
regional
global
scales.
Multiphase
involving
particles,
fog,
cloud
droplets
has
been
generally
thought
to
scale
with
liquid
water
content
(LWC)
so
multiphase
would
be
negligible
for
due
their
low
LWC.
However,
recent
field
evidence,
particularly
from
East
Asia,
shows
fast
sulfate
formation
prevails
in
cloud-free
environments
are
characterized
by
high
loadings.
By
assuming
the
kinetics
chemistry
most
atmospheric
models
do
not
capture
this
phenomenon.
Therefore,
blossomed
past
decade,
many
processes
proposed
bridge
difference
between
modeled
observed
mass
This
review
summarizes
advances
fundamental
understanding
SO2,
a
focus
environmental
conditions
affect
rate,
experimental
challenges,
mechanisms
results
individual
reaction
pathways,
future
research
directions.
Compared
dilute
conditions,
paper
highlights
differences
arise
at
molecular
level
extremely
solute
strengths
present
particles.
Proceedings of the National Academy of Sciences,
Journal Year:
2023,
Volume and Issue:
120(15)
Published: April 3, 2023
Hydroxyl
radical
(OH)
is
a
key
oxidant
that
triggers
atmospheric
oxidation
chemistry
in
both
gas
and
aqueous
phases.
The
current
understanding
of
its
sources
mainly
based
on
known
bulk
(photo)chemical
processes,
uptake
from
gaseous
OH,
or
related
to
interfacial
O
Journal of the American Chemical Society,
Journal Year:
2023,
Volume and Issue:
145(5), P. 2800 - 2805
Published: Jan. 27, 2023
Freshman
chemistry
teaches
that
Fe3+
and
Cu2+
ions
are
stable
in
water
solutions,
but
their
reduced
forms,
Fe2+
Cu+,
cannot
exist
as
the
major
oxidation
state
due
to
fast
by
O2
and/or
disproportionation.
Contrary
these
well-known
facts,
significant
fractions
of
dissolved
Fe
Cu
species
states
atmospheric
such
deliquesced
aerosols,
clouds,
fog
droplets.
Current
knowledge
attributes
phenomena
stabilization
lower
complexation
ligands
various
photochemical
or
thermal
pathways
can
reduce
higher
states.
In
this
study,
spraying
solutions
transition
metal
into
microdroplets,
we
show
results
spontaneous
reduction
ligated
Fe(III)
Cu(II)
Fe(II)
Cu(I)
species,
presenting
a
previously
unknown
source
water.
It
is
spontaneously
generated
electrons
microdroplets
responsible
for
reduction.
Control
experiments
atmosphere
glove
box
filled
with
precisely
controlled
gaseous
contents
reveal
O2,
CO2,
NO2
competitors
electrons,
forming
O2-,
HCO2-,
NO2-,
respectively.
Taking
findings
together,
opine
microdroplet
might
play
underestimated
roles
redox
chemistry.
Atmospheric chemistry and physics,
Journal Year:
2020,
Volume and Issue:
20(20), P. 11729 - 11746
Published: Oct. 17, 2020
Abstract.
Understanding
the
mechanism
of
haze
formation
is
crucial
for
development
deliberate
pollution
control
strategies.
Multiphase
chemical
reactions
in
aerosol
water
have
been
suggested
as
an
important
source
particulate
sulfate
during
severe
(Cheng
et
al.,
2016;
Wang
2016).
While
key
role
has
commonly
accepted,
relative
importance
different
oxidation
pathways
aqueous
phase
still
under
debate
mainly
due
to
questions
about
pH.
To
investigate
spatiotemporal
variability
pH
and
winter
North
China
Plain
(NCP),
we
developed
a
new
chemistry
(AWAC)
module
WRF-Chem
model
(Weather
Research
Forecasting
coupled
with
Chemistry).
Using
WRF-Chem-AWAC
model,
performed
comprehensive
survey
atmospheric
conditions
characteristic
wintertime
NCP
focusing
on
January
2013.
We
find
that
exhibited
strong
vertical
gradient
distinct
diurnal
cycle
which
was
closely
associated
variation
abundance
acidic
alkaline
fine
particle
components
their
gaseous
counterparts.
Over
Beijing,
average
at
surface
layer
∼5.4
remained
nearly
constant
around
∼5
up
∼2
km
above
ground
level;
further
aloft,
acidity
rapidly
increased
∼0
∼3
km.
The
pattern
increasing
altitude
persisted
over
NCP,
while
specific
levels
gradients
varied
between
regions.
In
region
north
∼41∘
N,
mean
values
level
were
typically
greater
than
6,
main
pathway
S(IV)
by
ozone.
South
range
4.4
5.7,
regimes
reaction
prevailed
four
regions
depending
reactant
concentrations
conditions.
NO2
megacity
Beijing
large
area
Hebei
Province
south
west
well
part
Shandong
Province.
transition
metal
ion
(TMI)
dominated
inland
coastal
east
H2O2
extending
(Shandong
Henan
provinces).
all
these
regions,
O3
TMI
water,
gas-particle
partitioning
H2SO4
vapor,
became
more
altitude.
Sensitivity
tests
show
rapid
production
can
be
maintained
wide
(e.g.,
=4.2–5.7)
transitions
from
dominant
NO2∕O3
regimes.
Atmospheric chemistry and physics,
Journal Year:
2022,
Volume and Issue:
22(5), P. 3017 - 3044
Published: March 7, 2022
Abstract.
Atmospheric
particles
experience
various
physical
and
chemical
processes
change
their
properties
during
lifetime.
Most
studies
on
atmospheric
particles,
both
in
laboratory
field
measurements,
rely
analyzing
an
ensemble
of
particles.
Because
different
mixing
states
individual
only
average
can
be
obtained
from
using
ensembles
To
better
understand
the
fate
environmental
impacts
investigations
at
a
single-particle
level
are
valuable.
Among
wealth
analytic
techniques,
Raman
spectroscopy
provides
unambiguous
characterization
under
pressure
non-destructive
situ
manner.
This
paper
comprehensively
reviews
application
such
technique
including
particle
hygroscopicity,
phase
transition
separation,
solute–water
interactions,
pH,
multiphase
reactions.
Investigations
enhanced
bioaerosols
basis
also
reviewed.
For
each
application,
we
describe
principle
representative
examples
studies.
Finally,
present
our
views
future
directions
development
further
applications
studying
Environmental Science & Technology,
Journal Year:
2022,
Volume and Issue:
56(15), P. 10608 - 10618
Published: July 5, 2022
Particulate
sulfate
is
one
of
the
most
important
components
in
atmosphere.
The
observation
rapid
aerosol
production
during
haze
events
provoked
scientific
interest
multiphase
oxidation
SO2
aqueous
particles.
Diverse
pathways
can
be
enhanced
or
suppressed
under
different
acidity
levels
and
high
ionic
strength
conditions
atmospheric
aerosol.
importance
to
chemistry
has
been
verified
laboratory
conditions,
though
studies
actual
atmosphere
are
still
limited.
By
utilizing
online
observations
developing
an
improved
solute
strength-dependent
chemical
thermodynamics
kinetics
model
(EF-T&K
model,
EF
enhancement
factor
that
represents
effect
on
aqueous-phase
reaction),
we
provided
quantitative
evidence
H2O2
pathway
was
nearly
100
times
dominated
formation
for
entire
years
(66%)
Tianjin
(a
northern
city
China).
TMI
(oxygen
catalyzed
by
transition-metal
ions)
(14%)
NO2
got
second-highest
contributions.
Machine
learning
supported
result
more
affected
pathway.
collaborative
effects
oxidants
were
further
investigated
using
EF-T&K
model.
Our
findings
highlight
effectiveness
adopting
target
oxidant
control
as
a
new
direction
sustainable
mitigation
sulfate,
given
already
low
concentrations
China.