Research Square (Research Square),
Год журнала:
2023,
Номер
unknown
Опубликована: Ноя. 16, 2023
Abstract
The
outbreak
of
COVID-19
(novel
coronavirus
2019)
led
to
a
significant
decrease
in
human
activities,
providing
unique
window
explore
the
potential
for
emission
control
and
subsequent
response
air
quality.
In
this
study,
we
investigated
concentration
trends
six
standard
pollutants
(PM
2.5
,
PM
10
SO
2
NO
CO,
O
3
)
Shenyang
during
pre-lockdown
period
(January
1
January
25,
2020),
lockdown
26
March
23,
post-lockdown
(March
24
May
20,
2020).
Additionally,
examined
relationships
between
atmospheric
these
three
periods
backward
trajectories
every
6
hours
hours.
results
showed
that
period,
reduction
pollution
was
closely
related
restriction
mobile
sources.
difference
AQI
(Air
Quality
Index)
northern
southern
regions
decreased
spatially.
Compared
mean
concentrations
CO
by
46.96%,
40.28%,
46.87%,
38.95%,
44.03%,
respectively.
However,
when
compared
same
2019
2021,
found
measures
did
not
significantly
Air
Index.
Only
SO2
decreases
2019,
while
variation
O3
minimally
affected
reduced
industrial
emissions
pandemic.
Furthermore,
using
composite
index
analysis,
combustion
main
source
pollutants.
We
speculated
increased
from
due
higher
demand
residential
heating
hindered
improvement
correlation
analysis
indicated
highly
positive
trace
gases
(SO2,
NO2,
CO)
all
periods,
suggesting
similar
sources
Long-range
regional
transport
mainly
originated
Mongolia
Russia
northwest
direction
Shenyang.
Therefore,
study
contributes
better
understanding
impact
different
on
pollution.
It
highlights
need
regionally
coordinated
balanced
strategies
controlling
multiple
future.
Journal of Geophysical Research Atmospheres,
Год журнала:
2022,
Номер
127(13)
Опубликована: Июнь 26, 2022
Abstract
Nitryl
chloride
(ClNO
2
)
is
an
important
chlorine
reservoir
in
the
atmosphere
that
affects
oxidation
capacity
by
producing
first‐
and
second‐generation
radicals,
but
it
has
been
rarely
observed
world.
Here,
online
measurements
of
both
N
O
5
ClNO
at
a
coastal
background
site
Pearl
River
Delta
(PRD)
southern
China,
region
with
high
atmospheric
daytime,
are
presented.
We
continuous
accumulation
elevated
night,
while
was
generally
low.
The
maximum
concentrations
were
1.4
1.7
ppbv,
respectively,
associated
transported
urban
plume
levels
3
NO
.
average
product
uptake
coefficient
yield
(γ
×
f
=
0.02,
γ
0.027
0.71)
roughly
twice
those
areas
indicating
active
heterogenous
chemistry
effective
formation
atmosphere.
production
rate
Cl
radicals
(
p
Cl)
from
photolysis
estimated
to
be
order
magnitude
higher
than
rural
sites
literature.
Such
radical
could
have
considerable
contribution
after
sunrise.
In
addition,
produced
morning
accounted
for
approximately
10%
increase
within
several
hours
Thus,
nocturnal
its
following
daytime
photochemistry
should
considered
seriously
regional
air
quality
modeling
PRD
regions
similar
conditions.
Environmental Research Letters,
Год журнала:
2024,
Номер
19(5), С. 054006 - 054006
Опубликована: Март 25, 2024
Abstract
As
the
concentration
of
fine
particles
(PM
2.5
)
is
declining,
ozone
(O
3
has
been
increasing
in
China
recent
years.
To
collaboratively
control
PM
and
O
,
it
critical
to
understand
relationship
between
two
identify
major
controlling
factors.
We
use
a
convergent
cross-mapping
method
detect
causal
daily
maximum
8
h
average
(MDA8)
concentrations
Beijing,
Taizhou,
Shenzhen
Chengdu,
China,
four
seasons
2015–2021.
In
addition,
we
also
examined
effects
atmospheric
oxidation
capacity,
precursors
meteorological
elements
on
MDA8
cities.
are
strongly
positively
correlated
show
bidirectional
relationships
during
Beijing
Taizhou
summer
Shenzhen,
due
mainly
strong
photochemical
reactions
daytime.
During
winter,
relationships,
but
significantly
negatively
correlated,
driven
by
NO
2
relative
humidity.
Weak
bidirectional,
unidirectional
no
detected
other
these
cities,
top
three
factors
differ
from
those
.
Season-,
city-
pollutant-specific
measures
required.
