Heliyon,
Год журнала:
2024,
Номер
10(22), С. e40085 - e40085
Опубликована: Ноя. 1, 2024
In
this
study,
34
volatile
organic
compounds
(VOCs)
were
analyzed
using
an
online
VOCs
instrument
at
30-min
intervals
from
November
16
to
23,
2023,
in
Ulaanbaatar
(UB),
the
capital
of
Mongolia
for
first
time.
The
average
concentration
was
13.0
±
11.1
ppb,
with
top
10
compounds,
such
as
benzene,
toluene,
ethylbenzene,
and
xylenes
(BTEX),
constituting
80
%
total.
concentrations
n-hexane,
n-heptane,
undecane
tended
increase
significantly
during
high-concentration
episode
period
(HEP).
Compared
other
studies,
BTEX
levels
UB
higher
than
those
Seoul
Beijing,
but
lower
Southeast
Asian
cities.
Positive
matrix
factorization
(PMF)
identified
four
sources:
vehicle
exhaust
(33.8
%),
industrial/coal
combustion
(25.3
secondary
formation
precursors
(21.3
solvent
usage
(19.6
%).
Vehicle
sources
increased
rush
hours
strongly
correlated
nitrogen
oxides.
During
HEP,
stagnant
air
mass
led
contributions
sources,
indicating
a
significant
local
impact.
Solvent
appeared
be
influenced
by
building
materials
exterior
painting
which
high
relative
humidity.
Secondary
daytime
highly
ozone.
Among
measured
benzene
assessed
lifetime
health
risk,
showing
that
adults
prolonged
exposure
exhibited
risk
infants
children.
However,
children
also
despite
their
shorter
duration.
Based
on
associated
risks,
results
highlight
need
policy
ambient
management
UB,
particular
focus
source
management.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(5), С. 3233 - 3252
Опубликована: Март 17, 2025
Abstract.
Air
pollutant
emissions
in
South
Korea
have
been
changing
rapidly
over
the
past
decade.
Here
we
analyze
resulting
2015–2023
trends
air
quality
and
regimes
using
surface
(AirKorea),
aircraft
(KORUS-AQ),
satellite
(low
Earth
orbit,
geostationary)
measurements.
Surface
concentrations
of
primary
pollutants
decreased
at
rates
(CO:
−2.6
±
0.7
%
a−1,
SO2:
−6.4
0.8
NO2:
−4.4
a−1)
consistent
with
national
Clean
Policy
Support
System
(CAPSS)
inventory
observations.
CAPSS
indicates
no
trend
volatile
organic
compound
(VOC)
emissions,
observations
formaldehyde
(HCHO)
glyoxal
(CHOCHO),
but
aromatic
show
a
5.0
3.9
a−1
decrease.
Peak
season
(May–June)
maximum
8
h
daily
average
(MDA8)
ozone
(O3)
exceeds
60
ppbv
standard
everywhere
AirKorea
sites,
an
increase
0.9
90th
percentile
averaged
across
all
sites
indicating
VOC-limited
conditions
for
O3
production.
However,
HCHO/NO2
ratios
indicate
shift
from
VOC-
to
NOx-limited
as
NOx
Most
are
Seoul
Metropolitan
Area
(SMA),
where
vestiges
persist;
find
increases
rest
Korea.
Fine
particulate
matter
(PM2.5)
has
decreasing
1.6
nitrate
(NO3-)
component
not.
Satellite
NH3/NO2
that
PM2.5
NO3-
formation
was
NH3-sensitive
before
2019
is
now
becoming
NOx-sensitive
Our
results
further
emission
decreases
will
reap
benefits
both
their
production
dominantly
NOx-sensitive.
Abstract
In
this
study,
the
modified
activated
carbon
(AC)
that
can
be
used
for
adsorption
of
acrylate
volatile
organic
compounds
(VOCs)
from
3D
printing,
is
produced
using
dual
modifiers
(H
2
O
and
KOH).
The
modification
strategy
exhibits
a
number
benefits
such
as
simple
operation,
mild
conditions,
low‐cost
process.
After
modification,
specific
surface
area
average
pore
diameter
AC
have
been
altered.
Energy
dispersive
spectroscopy
X‐ray
photoelectron
indicate
compared
to
pristine
AC,
C
element
content
decreases,
whereas
increases.
Fourier
transform
infrared
Boehm
titration
method
further
suggest
significant
increase
oxygen‐containing
groups
on
AC.
dynamic
experiments
breakthrough
tests
with
KOH)
significantly
improve
performance
toward
VOCs,
which
promising
use
in
VOCs
during
printing
Asian Journal of Atmospheric Environment,
Год журнала:
2024,
Номер
18(1)
Опубликована: Ноя. 5, 2024
Abstract
Seosan
is
a
concentrated
industrial
complex
in
the
midwestern
region
of
Korea.
A
study
was
conducted
from
December
2020
to
January
2021,
measuring
PM2.5
and
chemical
components
using
online
instruments
every
hour.
The
concentration
during
winter
season
31.4±17.8
μg/m
3
,
exceeding
national
ambient
air
quality
standard
mass
fraction
organic
matter,
elemental
carbon,
three
major
ions,
five
minor
crustal
elements,
trace
elements
accounted
for
24.5%,
4.36%,
32.0%,
2.82%,
4.11%,
5.17%
total
concentration,
respectively.
Source
identification
positive
matrix
factorization
modeling,
revealing
eight
sources
PM2.5:
Secondary
inorganic
aerosol
(SIA),
vehicle
exhaust,
industry,
coal
combustion,
biomass
burning/incinerator,
oil
soil,
aged
sea
salt.
contributions
varied
high
pollution
episodes
(HPE),
with
SIA
dominating
HPE1
soil
salt
HPE2.
potential
source
contribution
function
conditional
probability
were
utilized
estimate
local
regional
emission
areas
identified
sources.
In
Seosan,
exhaust
burning/incinerator
primarily
influenced
by
SIA,
combustion
significantly
affected
short-range
transport
eastern
China.
Soil
salt,
which
exhibited
HPE2,
associated
long-range
Inner
Mongolia.
Coal
attributed
both
sources,
particularly
large
complexes
near
Northeast
China
Graphical
Aerosol and Air Quality Research,
Год журнала:
2024,
Номер
24(8), С. 240031 - 240031
Опубликована: Янв. 1, 2024
PM2.5
mass
and
its
constituent
species
were
analyzed
in
two
coastal
cities
(Ulsan,
South
Korea,
Dalian,
China)
between
July
13,
2018,
September
20,
2019.
Ten
nine
sources
identified
Ulsan
respectively,
using
positive
matrix
factorization
(PMF).
In
Ulsan,
three
(secondary
nitrate
[SN],
secondary
sulfate
[SS],
traffic)
contributed
~83.0%
of
the
concentration
(23.7
µg
m-3)
during
heating
period.
four
(SN,
SS,
traffic,
residential
burning)
accounted
for
~84.3%
total
(47.8
m-3).
Higher
contributions
burning
Dalian
(11.7
than
biomass
(0.22
resolved
period
as
was
a
higher
proportion
SS
(6.28
m-3,
41.6%)
(6.42
21.2%)
non-heating
Squared
correlation
coefficients
(r2)
common
to
examined
lag
times
from
-2
days
+4
Ulsan.
The
largest
r2
concentrations
0.34
on
Lag
day
1.
same
day,
0.14
indicating,
stronger,
lagged
correlations
SN,
soil,
oil
combustion
sources,
with
values
0.25,
0.20,
0.41,
show
fair
these
Probable
source
locations
by
simplified
quantitative
transport
bias
analysis
(SQTBA)
potential
contribution
function
(PSCF)
multiple
site
approach
single
approach,
respectively.
Weaker
SN
(r2
=
0.15)
<
0.1)
supported
different
probable
locations.
This
study
requiring
individual
national
and/or
joint
international
efforts
reduce
ambient
neighboring
countries.
