Geophysical Research Letters,
Journal Year:
2022,
Volume and Issue:
49(21)
Published: Oct. 21, 2022
Abstract
Large‐scale
human
activity
changes
in
megacities
during
Chinese
New
Year
(CNY)
are
believed
to
significantly
affect
urban
heat
islands
(UHIs).
However,
the
urban‐rural
gradient
UHI
variations
responsive
cities
remains
largely
unclear.
Using
in‐situ
surface
air
temperature
obtained
from
a
meteorological
network
that
includes
3000‐plus
stations,
we
show
mean
intensity
(UHII)
31
capitals
is
0.52
±
0.23
K
CNY
holiday
and
0.77
0.29
reference
period,
indicating
UHII
reduction
of
0.25
0.20
holiday.
The
reduced
decreased
more
city
core
(0.54
K)
periphery
(0.071
K).
We
find
these
reductions
were
larger
at
night
than
day
northern
subtropical
warm
temperate
climates
other
climates.
These
mainly
attributable
decline
anthropogenic
release.
GeoHealth,
Journal Year:
2025,
Volume and Issue:
9(2)
Published: Feb. 1, 2025
Abstract
Extensive
lockdowns
during
the
COVID‐19
pandemic
caused
a
remarkable
decline
in
human
activities
that
have
influenced
urban
climate,
especially
air
quality
and
heat
islands.
However,
impact
of
such
changes
on
local
climate
based
long
term
ground‐level
observations
has
hitherto
not
been
investigated.
Using
pollution
measurements
for
four
major
Canadian
metropolitan
areas
(Toronto,
Montreal,
Vancouver,
Calgary),
we
find
PM
2.5
markedly
decreased
after
with
peak
reduction
ranging
between
42%
53%
relative
to
2000–2019
reference
period.
Moreover,
show
substantial
canopy
island
intensity
lockdown
post
periods
0.7°C
1.6°C
comparison
20‐year
preceding
The
results
this
study
may
provide
insights
policymakers
define
regulation
strategies
facilitate
improvement
areas.
Toxics,
Journal Year:
2025,
Volume and Issue:
13(5), P. 334 - 334
Published: April 24, 2025
The
impact
of
reduced
human
activity
on
air
quality
in
seven
major
Chinese
cities
was
investigated
by
utilizing
datasets
pollutants
and
meteorological
conditions
from
2016
to
2021.
A
Generalized
Additive
Model
(GAM)
developed
predict
during
reduced-activity
periods
rigorously
validated
against
ground
station
measurements,
achieving
an
R2
0.85–0.93.
Predictions
were
compared
the
observed
pollutant
reductions
(e.g.,
NO2
declined
34%
2020
vs.
2019),
confirming
model
reliability.
Transfer
learning
further
refined
accuracy,
reducing
RMSE
32–44%
across
when
benchmarked
real-world
data.
Notable
declines
Beijing
(42%),
Changchun
(38%),
Wuhan
(36%),
primarily
due
decreased
vehicular
traffic
industrial
activity.
Despite
occasional
anomalies
caused
localized
events
such
as
fireworks
(Beijing,
February
2020)
agricultural
burning
(Changchun,
April
2020),
our
findings
highlight
strong
influence
urban
quality.
These
results
offer
valuable
insights
for
designing
long-term
pollution
mitigation
strategies
policies.
npj Climate and Atmospheric Science,
Journal Year:
2022,
Volume and Issue:
5(1)
Published: June 2, 2022
Abstract
The
changes
in
human
behaviour
associated
with
the
spread
of
COVID-19
infections
have
changed
urban
environment.
However,
little
is
known
about
extent
to
which
they
climate,
especially
air
temperature
(
T
),
anthropogenic
heat
emission
Q
F
)
and
electricity
consumption
EC
).
We
quantitatively
evaluated
these
effects
using
a
unique
method
that
integrates
real-time
population
data
(social
big
data)
an
climate
model.
results
showed
office
district
city
centre
Tokyo,
biggest
metropolis
world,
under
significantly
reduced
population,
(CO
2
emissions)
would
be
30%
33%
pre-COVID
levels
(without
stay-at-home
advisories).
This
resulted
decrease
0.2
°C,
representing
20%
past
greenhouse
gas-induced
warming
(about
1.0
°C)
Tokyo.
can
benchmarked
then
applied
worldwide.
suggest
represent
adaptation
decarbonising
strategies
change
cities.
Energy Strategy Reviews,
Journal Year:
2022,
Volume and Issue:
44, P. 100963 - 100963
Published: Sept. 8, 2022
The
COVID-19
pandemic
has
threatened
city
economies
and
residents'
public
health
quality
of
life.
Similar
to
most
cities,
Melbourne
imposed
extreme
preventive
lockdown
measures
address
this
situation.
It
would
be
reasonable
assume
that
during
the
two
phases
lockdowns,
in
autumn
(March)
winter
(June
August)
2020,
air
parameters,
temperature,
Surface
Urban
Heat
Island
(SUHI),
lighting
energy
consumption
likely
increased.
As
such,
test
assumption,
Sentinel
5,
ERA-5
LAND,
1
2,
NASA
SRTM,
MODIS
Aqua
Terra,
VIIRS
satellite
imageries
are
utilized
investigate
alterations
NO₂,
SO₂,
CO,
UV
Aerosol
Index
(UAI),
SUHI,
factors
City
Melbourne.
Furthermore,
SentiThe
results
indicate
change
rates
NO₂
(1.17
mol/m2)
CO
(1.64
were
positive.
Further,
nighttime
SUHI
values
increased
by
approximately
0.417
°C
phase
lockdown,
while
summer
largest
negative
rate
was
(−100.40
mol/m2).
By
contrast,
positive
SO₂
at
night.
from
very
low
330
μm
mol/m2,
4.8
°C.
From
spatial
point
view,
study
also
shows
how
effects
on
such
parameters
shifted
based
urban
form
land
types
across
using
data
as
a
significant
resource
analyze
coverage
these
factors.
findings
demonstrate
factors,
changed
pre-lockdown
(2019)
(2020),
offering
valuable
insights
regarding
practices
for
managing
consumption,
pollution.
