Abstract.
Despite
significant
improvements
in
air
quality
recent
years,
the
Sichuan
Basin
(SCB)
is
still
facing
frequent
haze
pollution
winter.
In
this
study,
chemical
components
of
PM2.5
a
typical
period
at
beginning
2023
Chengdu,
megacity
SCB,
were
characterized
by
bulk-chemical
and
single-particle
analysis,
sources
formation
mechanism
analyzed.
The
average
mass
concentration
during
study
was
95.4±29.7
μg
m-3.
Organic
matter
(OM)
most
abundant
component
(35.3
%),
followed
nitrate
(22.0
sulfate
(9.2
%)
ammonium
(7.8
%).
aerosol
particles
classified
into
five
categories:
mineral,
OM,
S-rich,
soot
fly
ash/metal
particles,
them
state
internal
mixing.
entire
observation
could
be
divided
two
non-pollution
periods
(NP-1
NP-2)
(Haze-1
Haze-2).
With
evolution
pollution,
analysis
exhibited
similar
characteristics,
suggesting
that
Haze-1
mainly
caused
pollutants
related
to
fossil
fuel
combustion,
especially
mobile
sources,
while
Haze-2
triggered
rapidly
increasing
secondary
pollutants.
included
dust
(8.5
biomass
burning
(3.5
coal
combustion
(15.5
industrial
processes
(6.5
vehicular
emissions
(25.6
(40.5
Analysis
WRF-Chem
model
results
showed
contributions
local
regional
transmission
Chengdu
same
(50
%
vs
50
addition,
source
composition
simulation
different
confirmed
our
mechanisms
events.
This
confirms
that,
despite
reduction
experienced
past
decade,
further
reductions
are
needed,
with
particular
emphasis
on
sources.
High
intensity
or
large
amounts
may
cause
serious
events,
more
effective
policies
for
joint
prevention
control
necessary
future.
Atmospheric chemistry and physics,
Journal Year:
2022,
Volume and Issue:
22(5), P. 3275 - 3302
Published: March 11, 2022
Abstract.
Co-occurrences
of
high
concentrations
PM2.5
and
ozone
(O3)
have
been
frequently
observed
in
haze-aggravating
processes
the
North
China
Plain
(NCP)
over
past
few
years.
Higher
O3
on
hazy
days
were
hypothesized
to
be
related
nitrous
acid
(HONO),
but
key
sources
HONO
enhancing
during
remain
unclear.
We
added
six
potential
sources,
i.e.,
four
ground-based
(traffic,
soil,
indoor
emissions,
NO2
heterogeneous
reaction
ground
surface
(Hetground))
two
aerosol-related
(the
aerosol
surfaces
(Hetaerosol)
nitrate
photolysis
(Photnitrate))
into
WRF-Chem
model
designed
23
simulation
scenarios
explore
unclear
sources.
The
results
indicate
that
producing
enhancements
showed
a
rapid
decrease
with
height,
while
NO
+
OH
decreased
slowly
height.
Photnitrate
contributions
enhanced
aggravated
pollution
levels.
enhancement
due
was
about
10
times
greater
than
clean
dominated
daytime
(∼
30
%–70
%
when
ratio
frequency
(Jnitrate)
gas
nitric
(JHNO3)
equals
30)
at
higher
layers
(>800
m).
Compared
days,
contribution
daily
maximum
8
h
averaged
(DMA8)
increased
by
1
magnitude
process.
contributed
only
∼
5
Jnitrate/JHNO3
%–50
near
NCP
days.
Surface
volatile
organic
compound-sensitive
chemistry,
altitudes
m)
NOx-sensitive
chemistry.
had
limited
impact
(<15
%)
even
120.
These
suggest
significant
formation,
more
comprehensive
studies
atmosphere
are
still
needed.
Atmospheric chemistry and physics,
Journal Year:
2024,
Volume and Issue:
24(5), P. 2803 - 2820
Published: March 4, 2024
Abstract.
Despite
significant
improvements
in
air
quality
recent
years,
the
Sichuan
Basin
(SCB)
is
still
facing
frequent
haze
pollution
winter,
and
causes
of
severe
formation
have
not
yet
been
fully
investigated.
In
this
study,
chemical
components
PM2.5
(i.e.,
particulate
matter
with
an
aerodynamic
diameter
less
than
2.5
µm)
a
typical
period
at
beginning
2023
Chengdu,
megacity
SCB,
were
characterized
by
bulk-chemical
single-particle
analysis,
sources
mechanism
analyzed.
The
average
mass
concentration
during
study
was
95.6
±
28.7
µg
m−3.
Organic
(OM)
most
abundant
component
(35.3
%),
followed
nitrate
(22.0
sulfate
(9.2
%)
ammonium
(7.8
%).
individual
aerosol
particles
classified
into
five
categories,
i.e.,
mineral,
OM,
secondary
inorganic
(SIA),
soot
fly
ash/metal
particles,
them
state
being
internally
mixed.
entire
observation
could
be
divided
two
non-pollution
periods
(NP-1
NP-2)
(Haze-1
Haze-2).
With
evolution
pollution,
analysis
exhibited
similar
characteristics,
suggesting
that
Haze-1
mainly
caused
pollutants
related
to
fossil
fuel
combustion,
especially
local
mobile
sources,
while
Haze-2
triggered
rapidly
increasing
pollutants,
which
came
from
regional
transmission.
included
dust
(8.5
biomass
burning
(3.5
coal
combustion
(15.4
industrial
processes
(6.5
vehicular
emissions
(25.6
(40.5
Analysis
Weather
Research
Forecasting
model
Chemistry
(WRF-Chem)
results
showed
contributions
transmission
Chengdu
same
(50
%
vs.
50
addition,
source
composition
WRF-Chem
simulation
different
confirmed
our
mechanisms
events.
This
confirms
further
reductions
are
needed,
more
effective
policies
for
emission
reduction
or
joint
prevention
control
will
necessary
future.
Frontiers in Environmental Science,
Journal Year:
2022,
Volume and Issue:
10
Published: Feb. 18, 2022
Surface
ozone
(O
3
)
increased
by
∼20%
in
the
Yangtze
River
Delta
(YRD)
region
of
China
during
2014–2020,
but
aggravating
trend
is
highly
variable
on
interannual
time
and
city-level
space
scales.
Here,
we
employed
multiple
air
quality
observations
numerical
simulation
to
describe
increasing
O
reveal
main
driving
factors
behind
it.
In
2014–2017,
governmental
pollution
control
action
plan
was
mostly
against
PM
2.5
(mainly
emissions
SO
2
,
NO
x
primary
effectively
reduced
concentration
18%–45%.
However,
worsened
same
period
with
an
rate
4.9
μg
m
−3
yr
−1
especially
Anhui
province,
where
growth
even
reached
14.7
.
After
2018,
owing
coordinated
prevention
both
volatile
organic
compound
(VOC)
YRD
has
also
been
controlled
a
great
concern,
obviously
alleviated
(1.1
).
We
further
combined
precursor
corresponding
formation
regime
explain
observed
2014–2020.
The
leading
2014–2017
diagnosed
as
VOC-limited
(21%)
or
mix-limited
(58%),
help
simulated
indicator
HCHO/NO
y
Under
such
condition,
decreasing
(2.8%
VOCs
(3.6%
led
rapid
increment
With
continuous
reduction
emission
ambient
/VOCs,
production
along
shifting
from
mix-limited,
after
become
dominant
for
55%
cities.
Consequently,
decreases
(3.3%
(7.7%
2018–2020
slowed
down
Our
study
argues
that
implementation
regional
VOCs,
effective
emerging
region.
