Atmosphere,
Journal Year:
2021,
Volume and Issue:
12(8), P. 946 - 946
Published: July 23, 2021
China
was
the
first
country
to
undergo
large-scale
lockdowns
in
response
pandemic
early
2020
and
a
progressive
return
normalization
after
April
2020.
Spaceborne
observations
of
atmospheric
nitrogen
dioxide
(NO2)
oxygenated
volatile
organic
compounds
(OVOCs),
including
formaldehyde
(HCHO),
glyoxal
(CHOCHO),
peroxyacetyl
nitrate
(PAN),
reveal
important
changes
over
2020,
relative
2019,
pandemic-induced
shutdown
subsequent
drop
pollutant
emissions.
In
February,
at
peak
shutdown,
observed
declines
OVOC
levels
were
generally
weaker
(less
than
20%)
compared
NO2
reductions
(−40%).
May
moderate
decreases
(−15%)
PAN
(−21%),
small
CHOCHO
(−3%)
HCHO
(6%).
Model
simulations
using
regional
model
MAGRITTEv1.1
with
anthropogenic
emissions
accounting
for
due
explain
large
extent
lockdown-affected
regions.
The
results
suggest
that
meteorological
variability
accounts
minor
but
non-negligible
part
(~−5%)
NO2,
whereas
it
is
negligible
plays
more
substantial
role
PAN,
especially
May.
interannual
biogenic
biomass
burning
also
contribute
variations,
explaining
e.g.,
column
increases
OVOCs
February
2019.
These
are
well
captured
by
simulations.
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.
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.
Earth system science data,
Journal Year:
2021,
Volume and Issue:
13(8), P. 4191 - 4206
Published: Aug. 26, 2021
Abstract.
In
order
to
fight
the
spread
of
global
COVID-19
pandemic,
most
world's
countries
have
taken
control
measures
such
as
lockdowns
during
a
few
weeks
months.
These
had
significant
impacts
on
economic
and
personal
activities
in
many
countries.
Several
studies
using
satellite
surface
observations
reported
important
changes
spatial
temporal
distributions
atmospheric
pollutants
greenhouse
gases.
Global
regional
chemistry-transport
model
are
being
performed
analyze
impact
these
distribution
compounds.
modeling
aim
at
evaluating
scale.
provide
input
for
simulations,
dataset
providing
adjustment
factors
(AFs)
that
can
easily
be
applied
current
emission
inventories
has
been
developed.
This
provides,
January–August
2020
period,
gridded
AFs
0.1×0.1
latitude–longitude
degree
resolution
daily
or
monthly
basis
transportation
(road,
air
ship
traffic),
power
generation,
industry
residential
sectors.
The
quantification
is
based
activity
data
collected
from
different
databases
previously
published
studies.
A
range
provided
each
grid
point
sensitivity
developed
this
study
CAMS
inventory
(CAMS-GLOB-ANT_v4.2_R1.1),
emissions
main
discussed
regions
world
first
6
months
2020.
Maximum
decreases
total
found
February
eastern
China,
with
an
average
reduction
20
%–30
%
NOx,
NMVOCs
(non-methane
volatile
organic
compounds)
SO2
relative
reference
emissions.
other
regions,
maximum
occur
April,
reductions
CO
Europe
North
America
larger
(30
%–50
%)
South
America.
India
African
NOx
NMVOC
reduced
by
15
%.
For
species,
generally
less
than
%,
except
America,
where
large
BC
(black
carbon)
estimated.
As
paper,
vary
highly
across
sectors
due
differences
duration
before
partial
complete
recovery.
(average
±
standard
deviation)
called
CONFORM
(COvid-19
adjustmeNt
Factors
fOR
eMissions)
(https://doi.org/10.25326/88;
Doumbia
et
al.,
2020).
It
distributed
Emissions
Compounds
Compilation
Ancillary
Data
(ECCAD)
database
(https://eccad.aeris-data.fr/,
last
access:
23
August
2021).
Atmospheric chemistry and physics,
Journal Year:
2022,
Volume and Issue:
22(1), P. 641 - 674
Published: Jan. 17, 2022
Aerosol-cloud
interactions
(ACIs)
are
considered
to
be
the
most
uncertain
driver
of
present-day
radiative
forcing
due
human
activities.
The
nonlinearity
cloud-state
changes
aerosol
perturbations
make
it
challenging
attribute
causality
in
observed
relationships
forcing.
Using
correlations
infer
can
when
meteorological
variability
also
drives
both
and
cloud
independently.
Natural
anthropogenic
from
well-defined
sources
provide
"opportunistic
experiments"
(also
known
as
natural
experiments)
investigate
ACI
cases
where
may
more
confidently
inferred.
These
cover
a
wide
range
locations
spatiotemporal
scales,
including
point
such
volcanic
eruptions
or
industrial
sources,
plumes
biomass
burning
forest
fires,
tracks
individual
ships
shipping
corridors.
We
review
different
experimental
conditions
conduct
synthesis
available
satellite
datasets
field
campaigns
place
these
opportunistic
experiments
on
common
footing,
facilitating
new
insights
clearer
understanding
key
uncertainties
Cloud
albedo
strongly
sensitive
background
conditions.
Strong
liquid
water
path
increases
largely
ruled
out
by
averaging
across
experiments.
Opportunistic
have
significantly
improved
process-level
ACI,
but
remains
unclear
how
reliably
found
scaled
global
level,
thus
demonstrating
need
for
deeper
investigation
order
improve
assessments
climate
change.
Atmospheric chemistry and physics,
Journal Year:
2025,
Volume and Issue:
25(5), P. 2937 - 2946
Published: March 11, 2025
Abstract.
Aerosol
interactions
with
clouds
represent
a
significant
uncertainty
in
our
understanding
of
the
Earth
system.
Deep
convective
may
respond
to
aerosol
perturbations
several
ways
that
have
proven
difficult
elucidate
observations.
Here,
we
leverage
two
busiest
maritime
shipping
lanes
world,
which
emit
particles
and
their
precursors
into
an
otherwise
relatively
clean
tropical
marine
boundary
layer,
make
headway
on
influence
deep
clouds.
The
recent
7-fold
change
allowable
fuel
sulfur
by
International
Maritime
Organization
allows
us
test
sensitivity
lightning
changes
ship
plume
number-size
distributions.
We
find
that,
across
range
atmospheric
thermodynamic
conditions,
previously
documented
enhancement
over
has
fallen
40
%.
is
therefore
at
least
partially
aerosol-mediated,
conclusion
supported
observations
droplet
number
cloud
base,
show
similar
decline
lane.
These
results
fundamental
implications
for
aerosol–cloud
interactions,
suggesting
are
impacted
distribution
remote
environment.
Geophysical Research Letters,
Journal Year:
2020,
Volume and Issue:
47(17)
Published: Aug. 25, 2020
Following
the
emergence
of
a
novel
coronavirus
in
Wuhan,
China
instituted
shutdown
measures
starting
late
January
and
continuing
into
February
2020
to
arrest
spread
disease.
This
resulted
sharp
economic
contraction
unparalleled
recent
Chinese
history.
Satellite
retrievals
show
that
nitrogen
dioxide
pollution
declined
by
an
unprecedented
amount
(~50%
regionally)
from
its
expected
unperturbed
value,
but
regional-scale
column
aerosol
loadings
cloud
microphysical
properties
were
not
detectably
affected.
The
disparate
impact
is
tied
differential
impacts
shutdown,
which
transportation,
disproportionate
source
oxide
emissions,
underwent
drastic
declines
(~90%
reductions
passenger
traffic),
whereas
industry
power
generation,
responsible
for
>90%
particulate
relatively
less
affected
(~20%
electricity
thermal
generation).
A
combination
anomalously
warm
humid
meteorological
conditions
complex
chemical
interactions
further
decreased
concentrations
likely
enhanced
secondary
formation.
Geophysical Research Letters,
Journal Year:
2021,
Volume and Issue:
48(8)
Published: March 11, 2021
Abstract
Many
nations
responded
to
the
corona
virus
disease‐2019
(COVID‐19)
pandemic
by
restricting
travel
and
other
activities
during
2020,
resulting
in
temporarily
reduced
emissions
of
CO
2
,
greenhouse
gases
ozone
aerosol
precursors.
We
present
initial
results
from
a
coordinated
Intercomparison,
CovidMIP,
Earth
system
model
simulations
which
assess
impact
on
climate
these
reductions.
12
models
performed
multiple
initial‐condition
ensembles
produce
over
300
spanning
both
condition
structural
uncertainty.
find
consensus
amounts
(particularly
southern
eastern
Asia)
associated
increases
surface
shortwave
radiation
levels.
However,
any
near‐surface
temperature
or
rainfall
2020–2024
is
extremely
small
not
detectable
this
analysis.
Regional
analyses
finer
scale,
closer
attention
extremes
(especially
linked
changes
atmospheric
composition
air
quality)
are
required
test
COVID‐19‐related
emission
reductions
near‐term
climate.
Geophysical Research Letters,
Journal Year:
2020,
Volume and Issue:
48(3)
Published: Dec. 30, 2020
Abstract
The
COVID‐19
pandemic
led
to
dramatic
changes
in
economic
activity
2020.
We
use
estimates
of
emission
for
2020
two
Earth
System
Models
(ESMs)
simulate
the
impacts
changes.
Ensembles
nudged
simulations
are
used
separate
small
signals
from
meteorological
variability.
Reductions
aerosol
and
precursor
emissions,
chiefly
black
carbon
sulfate
(SO
4
),
reductions
total
anthropogenic
cooling
through
aerosol‐cloud
interactions.
average
overall
Effective
Radiative
Forcing
(ERF)
peaks
at
+0.29
±
0.15
Wm
−2
spring
Changes
cloud
properties
smaller
than
observed
during
Impacts
these
on
regional
land
surface
temperature
range
up
+0.3
K.
peak
impact
global
is
very
(+0.03
K).
However,
largest
contribution
radiative
forcing
as
a
result
affected
larger
ozone,
CO
2
contrail
effects.