Elementa Science of the Anthropocene,
Journal Year:
2021,
Volume and Issue:
9(1)
Published: Jan. 1, 2021
The
coronavirus-19
(COVID-19)
pandemic
led
to
government
interventions
limit
the
spread
of
disease
which
are
unprecedented
in
recent
history;
for
example,
stay
at
home
orders
sudden
decreases
atmospheric
emissions
from
transportation
sector.
In
this
review
article,
current
understanding
influence
emission
reductions
on
pollutant
concentrations
and
air
quality
is
summarized
nitrogen
dioxide
(NO2),
particulate
matter
(PM2.5),
ozone
(O3),
ammonia,
sulfur
dioxide,
black
carbon,
volatile
organic
compounds,
carbon
monoxide
(CO).
first
7
months
following
onset
pandemic,
more
than
200
papers
were
accepted
by
peer-reviewed
journals
utilizing
observations
ground-based
satellite
instruments.
Only
about
one-third
literature
incorporates
a
specific
method
meteorological
correction
or
normalization
comparing
data
lockdown
period
with
prior
reference
despite
importance
doing
so
interpretation
results.
We
use
stringency
index
(SI)
as
an
indicator
severity
measures
show
how
key
pollutants
change
SI
increases.
observed
decrease
NO2
increasing
general
agreement
inventories
that
account
lockdown.
Other
compounds
such
O3,
PM2.5,
CO
also
broadly
covered.
Due
chemistry
O3
PM2.5
concentrations,
their
responses
may
not
be
linear
respect
primary
pollutants.
At
most
sites,
we
found
increased,
whereas
decreased
slightly,
SI.
Changes
other
understudied.
highlight
future
research
needs
emerging
sets
preview
state
atmosphere
world
targeted
permanent
emissions.
Finally,
emphasize
need
effects
meteorology,
trends,
when
determining
concentrations.
Atmospheric chemistry and physics,
Journal Year:
2021,
Volume and Issue:
21(9), P. 7253 - 7269
Published: May 12, 2021
Abstract.
Ground-level
ozone
(O3)
pollution
has
been
steadily
getting
worse
in
most
parts
of
eastern
China
during
the
past
5
years.
The
non-linearity
O3
formation
with
its
precursors
like
nitrogen
oxides
(NOx=
NO
+
NO2)
and
volatile
organic
compounds
(VOCs)
are
complicating
effective
abatement
plans.
diagnosis
from
space-based
observations,
i.e.
ratio
formaldehyde
(HCHO)
columns
to
tropospheric
NO2
(HCHO
/
NO2),
previously
proved
be
highly
consistent
our
current
understanding
surface
chemistry.
HCHO
thresholds
distinguishing
sensitivity
depend
on
regions
chemistry
interactions
aerosol.
To
shed
more
light
over
China,
we
have
derived
by
directly
connecting
satellite-based
observations
ground-based
measurements
major
Chinese
cities
this
study.
We
find
that
a
VOC-limited
regime
occurs
for
<
2.3,
NOx-limited
>
4.2.
between
2.3
4.2
reflects
transition
two
regimes.
Our
method
shows
tends
urban
areas
rural
remote
China.
there
is
shift
some
transitional
associated
rapid
drop
anthropogenic
NOx
emissions,
owing
widely
applied
rigorous
emission
control
strategies
2016
2019.
This
detected
spatial
expansion
supported
rising
concentrations.
enhanced
concentrations
COVID-19
lockdown
indicate
protocol
simultaneous
emissions
VOC
controls
essential
Geophysical Research Letters,
Journal Year:
2021,
Volume and Issue:
48(5)
Published: Feb. 10, 2021
Abstract
Throughout
spring
and
summer
2020,
ozone
stations
in
the
northern
extratropics
recorded
unusually
low
free
troposphere.
From
April
to
August,
from
1
8
kilometers
altitude,
was
on
average
7%
(≈4
nmol/mol)
below
2000–2020
climatological
mean.
Such
ozone,
over
several
months,
at
so
many
stations,
has
not
been
observed
any
previous
year
since
least
2000.
Atmospheric
composition
analyses
Copernicus
Atmosphere
Monitoring
Service
simulations
NASA
GMI
model
indicate
that
large
2020
springtime
depletion
Arctic
stratosphere
contributed
less
than
one‐quarter
of
tropospheric
anomaly.
The
anomaly
is
consistent
with
recent
chemistry‐climate
simulations,
which
assume
emissions
reductions
similar
those
caused
by
COVID‐19
crisis.
related
appear
be
major
cause
for
reduced
2020.
Journal of Geophysical Research Atmospheres,
Journal Year:
2021,
Volume and Issue:
126(8)
Published: April 15, 2021
Abstract
We
use
the
global
Community
Earth
System
Model
to
investigate
response
of
secondary
pollutants
(ozone
O
3
,
organic
aerosols
SOA)
in
different
parts
world
modified
emissions
primary
during
COVID‐19
pandemic.
quantify
respective
effects
reductions
NOx
and
volatile
carbon
(VOC)
emissions,
which,
most
cases,
affect
oxidants
opposite
ways.
Using
model
simulations,
we
show
that
level
has
been
reduced
by
typically
40%
China
February
2020
similar
amounts
many
areas
Europe
North
America
mid‐March
mid‐April
2020,
good
agreement
with
space
surface
observations.
that,
relative
a
situation
which
emission
are
ignored
despite
calculated
increase
hydroxyl
peroxy
radicals,
ozone
concentration
increased
only
few
NOx‐saturated
regions
(northern
China,
northern
Europe,
US)
winter
months
pandemic
when
titration
this
molecule
was
reduced.
In
other
regions,
where
is
NOx‐controlled,
decreased.
SOA
concentrations
decrease
concurrent
reduction
VOC
emissions.
The
also
shows
atmospheric
meteorological
anomalies
produced
substantial
variations
chemical
species
for
example,
large
fraction
associated
anomalies,
while
Plain,
enhanced
resulted
primarily
from
pollutants.
