Atmospheric chemistry and physics,
Journal Year:
2020,
Volume and Issue:
20(5), P. 2839 - 2863
Published: March 6, 2020
Abstract.
Diurnal
variation
of
surface
PM2.5
concentration
(diurnal
PM2.5)
could
dramatically
affect
aerosol
radiative
and
health
impacts
can
also
well
reflect
the
physical
chemical
mechanisms
air
pollution
formation
evolution.
So
far,
diurnal
its
modeling
capability
over
East
China
have
not
been
investigated
therefore
are
examined
in
this
study.
Based
on
observations,
normalized
amplitude
concentrations
averaged
is
weakest
(∼1.2)
winter
reaches
∼1.5
other
seasons.
The
shows
peak
during
night
spring
fall
daytime
summer.
simulated
with
WRF-Chem
contributions
from
multiple
processes
four
primarily
controlled
by
planetary
boundary
layer
(PBL)
mixing
emission
variations
significantly
overestimated
against
observation
night.
This
bias
likely
due
to
inefficient
PBL
primary
sensitive
schemes
vertical-layer
configurations
WRF-Chem.
Besides
height,
coefficient
found
be
critical
factor
determining
pollutants
With
reasonable
increase
lower
limit
reduce
biases
mean
concentrations,
particularly
major
cities
China.
It
sensitivity
configurations.
injection
height
anthropogenic
emissions
play
roles
simulating
PM2.5,
but
impact
relatively
smaller
than
that
mixing.
study
underscores
more
efforts
needed
improve
process
models
observations
structure
fluxes
addition
order
simulate
reasonably
must
included
Environmental Science & Technology Letters,
Journal Year:
2019,
Volume and Issue:
6(12), P. 752 - 760
Published: Nov. 4, 2019
During
recent
years,
aggressive
air
pollution
mitigation
measures
in
northern
China
have
resulted
considerable
changes
gas
and
aerosol
chemical
composition.
But
it
is
unclear
whether
water
content
acidity
respond
to
these
changes.
The
two
parameters
been
shown
affect
heterogeneous
production
of
winter
haze
aerosols.
Here,
we
performed
thermodynamic
equilibrium
modeling
using
meteorological
data
observed
urban
Beijing
for
four
seasons
quantified
the
mass
growth
factor
pH
inorganic
We
focused
on
high
relative
humidity
(>60%)
conditions
when
submicron
particles
be
liquid
state.
From
2014/2015
2018/2019,
modeled
decreased
by
about
9%–17%
due
compositions
(more
nitrate
less
sulfate
chloride),
increased
0.3–0.4
unit
mainly
rising
ammonia.
A
buffer
equation
derived
from
semivolatile
ammonia
partitioning,
which
helps
understand
sensitivity
variables.
findings
provide
implications
evaluating
potential
feedback
secondary
effectiveness
control
as
a
measure
alleviate
haze.
Environment International,
Journal Year:
2020,
Volume and Issue:
137, P. 105592 - 105592
Published: Feb. 27, 2020
In
China,
nitrate
(NO3−)
becomes
the
main
contributor
to
fine
particles
(PM2.5)
because
emissions
of
its
precursor,
nitrogen
oxides
(NOx),
were
not
recognized
and
controlled
well
in
recent
years.
this
work,
sources,
conversion,
geographical
origin
NOx
interpreted
combining
isotopic
information
(δ15N
δ18O)
NO3−
dual
modelling
at
five
Chinese
megacities
(Beijing,
Shanghai,
Guangzhou,
Wuhan
Chengdu)
during
2013–2014.
Results
showed
that
δ15N-NO3−
values
(n
=
512)
ranged
from
−12.3‰
+22.9‰,
average
δ18O-NO3−
value
was
+83.4‰
±
17.2‰.
The
compositions
both
had
a
rising
tendency
as
ambient
temperature
dropped,
attributing
largely
source
changes.
Bayesian
model
indicated
percentage
for
OH
pathway
conversion
clear
seasonal
variation
with
higher
summer
(58.0%
9.82%)
lower
winter
(11.1%
3.99%);
it
also
significantly
correlated
latitude
(p
<
0.01).
Coal
combustion
most
important
(31.1%−41.0%),
which
geographically
derived
North
China
other
south-central
developed
regions
implied
by
Potential
Source
Contribution
Function
(PSCF).
Apart
Chengdu,
mobile
sources
second
largest
NOx.
This
extensive
but
uniformly
distributed
all
around
typical
urban
agglomerations
China.
Biomass
burning
microbial
processes
shared
similar
areas,
mostly
originating
Plain
Sichuan
Basin.
Based
on
features,
we
infer
residential
coal
primary
heavy
PM2.5
pollution
megacities.
Controlling
categories
these
regional
priorities
would
help
mitigate
atmospheric
areas.
Atmospheric chemistry and physics,
Journal Year:
2020,
Volume and Issue:
20(21), P. 12721 - 12740
Published: Nov. 4, 2020
Abstract.
Although
secondary
particulate
matter
is
reported
to
be
the
main
contributor
of
PM2.5
during
haze
in
Chinese
megacities,
primary
particle
emissions
also
affect
concentrations.
In
order
improve
estimates
contribution
sources
number
and
mass
concentrations,
we
performed
source
apportionment
analyses
using
both
chemical
fingerprints
size
distributions
measured
at
same
site
urban
Beijing
from
April
July
2018.
Both
methods
resolved
factors
related
emissions,
including
vehicular
cooking
which
together
make
up
76
%
24
total
organic
aerosol
(OA)
mass,
respectively.
Similar
types,
particles
(1.6±1.1
µg
m−3;
2.4±1.8×103
cm−3
5.5±2.8×103
for
two
traffic-related
components),
(2.6±1.9
m−3
5.5±3.3×103
cm−3)
aerosols
(51±41
4.2±3.0×103
cm−3),
were
by
methods.
Converted
concentrations
components
comparable
with
those
fingerprints.
Size
distribution
separated
into
a
component
mode
diameter
20
nm
(“traffic-ultrafine”)
100
(“traffic-fine”).
Consistent
similar
day-
nighttime
diesel
vehicle
estimated
area,
traffic-fine
particles,
hydrocarbon-like
OA
(HOA,
factor
resulting
fingerprints)
black
carbon
(BC)
showed
diurnal
patterns,
higher
night
morning
than
afternoon
when
boundary
layer
higher.
Traffic-ultrafine
highest
rush-hour
period,
suggesting
prominent
role
local
gasoline
emissions.
absence
new
formation,
our
results
show
that
vehicular-related
(14
30
ultrafine
fine
respectively)
cooking-activity-related
(32
%)
dominate
concentration,
while
(over
80
governs
non-heating
season
Beijing.
Atmospheric chemistry and physics,
Journal Year:
2020,
Volume and Issue:
20(5), P. 2839 - 2863
Published: March 6, 2020
Abstract.
Diurnal
variation
of
surface
PM2.5
concentration
(diurnal
PM2.5)
could
dramatically
affect
aerosol
radiative
and
health
impacts
can
also
well
reflect
the
physical
chemical
mechanisms
air
pollution
formation
evolution.
So
far,
diurnal
its
modeling
capability
over
East
China
have
not
been
investigated
therefore
are
examined
in
this
study.
Based
on
observations,
normalized
amplitude
concentrations
averaged
is
weakest
(∼1.2)
winter
reaches
∼1.5
other
seasons.
The
shows
peak
during
night
spring
fall
daytime
summer.
simulated
with
WRF-Chem
contributions
from
multiple
processes
four
primarily
controlled
by
planetary
boundary
layer
(PBL)
mixing
emission
variations
significantly
overestimated
against
observation
night.
This
bias
likely
due
to
inefficient
PBL
primary
sensitive
schemes
vertical-layer
configurations
WRF-Chem.
Besides
height,
coefficient
found
be
critical
factor
determining
pollutants
With
reasonable
increase
lower
limit
reduce
biases
mean
concentrations,
particularly
major
cities
China.
It
sensitivity
configurations.
injection
height
anthropogenic
emissions
play
roles
simulating
PM2.5,
but
impact
relatively
smaller
than
that
mixing.
study
underscores
more
efforts
needed
improve
process
models
observations
structure
fluxes
addition
order
simulate
reasonably
must
included
