Research Square (Research Square),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Feb. 16, 2024
Abstract
Chlorine
radical
(Cl·)
profoundly
impacts
atmospheric
oxidation
capacity,
and
therefore
climate
change
air
pollution.
Chloramines,
especially
trichloramine
(NCl3),
is
a
potentially
important
Cl·
source,
while
their
formation
mechanism
remains
elusive.
Here,
we
present
evidence
of
aerosol
aqueous-phase
production
chloramines
with
observations
in
Beijing
develop
comprehensive
box
model
which
incorporates
~40
aqueous
reactions
initiated
by
Cl2
NH3
multiple
phase
transfer
processes.
The
can
well
reproduce
the
diurnal
variation
NCl3.
We
show
that
this
could
be
ubiquitous
globally
co-existence
water,
Cl2,
NH3,
NCl3
mainly
influenced
relative
humidity
as
typically
great
excess.
contribution
(mostly
NCl3)
to
much
higher
clean
periods
(up
85%)
than
polluted
(~5%)
Beijing,
environments
(e.g.,
~64%
Canada)
areas
~1%
India).
Therefore,
play
an
increasingly
role
cleaner
future
may
partially
offset
on-going
efforts
on
pollution
mitigation.
missing
representation
current
models
significantly
underestimate
climate,
health
ecological
Cl·.
Environmental Science & Technology,
Journal Year:
2024,
Volume and Issue:
58(20), P. 8815 - 8824
Published: May 11, 2024
This
study
presents
the
measurement
of
photochemical
precursors
during
lockdown
period
from
January
23,
2020,
to
March
14,
in
Chengdu
response
coronavirus
(COVID-19)
pandemic.
To
derive
impact
on
air
quality,
observations
are
compared
equivalent
periods
last
2
years.
An
observation-based
model
is
used
investigate
atmospheric
oxidation
capacity
change
lockdown.
OH,
HO2,
and
RO2
concentrations
simulated,
which
elevated
by
42,
220,
277%,
respectively,
period,
mainly
due
reduction
nitrogen
oxides
(NOx).
However,
radical
turnover
rates,
i.e.,
OH
rate
L(OH)
local
ozone
production
P(O3),
determine
secondary
intermediates
formation
O3
formation,
only
increase
24
48%,
respectively.
Therefore,
increases
slightly
lockdown,
partly
attributed
unchanged
alkene
concentrations.
During
ozonolysis
seems
be
a
significant
primary
source
unique
data
set
highlights
importance
controlling
emission
mitigate
pollution
may
also
applicable
other
regions
China
given
an
expected
NOx
rapid
transformation
electrified
fleets
future.
Atmospheric chemistry and physics,
Journal Year:
2025,
Volume and Issue:
25(1), P. 73 - 91
Published: Jan. 7, 2025
Abstract.
Reports
on
the
molecular-level
characterization
of
primary
and
secondary
constituents
in
PM2.5
at
high
temporal
resolution,
particularly
during
haze
events,
are
still
limited.
This
study
employed
comprehensive
analytical
methods
to
examine
molecular
composition
source
contributions
PM2.5,
with
samples
collected
approximately
every
2
h
hazy
winter
days.
Results
show
that
organic
matter
was
predominant
species,
followed
by
nitrate
(NO3-).
Radiocarbon
analysis
carbonaceous
fractions
reveals
fossil
fuels
account
for
61
%–82
%
water-soluble
carbon
(WSOC),
likely
resulting
from
increased
fuel
consumption
cold
heating
months.
Interestingly,
contribution
non-fossil
sources
WSOC
enhanced
worsening
pollution,
coinciding
significantly
intensified
biomass
burning
(BB).
BB
identified
as
largest
contributor
(OC)
both
concentration
proportion,
due
intensive
emissions
surrounding
areas,
especially
heavily
polluted
For
sources,
naphthalene-derived
(SOC)
contributed
more
OC
(0.27
%–2.46
%)
compared
biogenic
SOC
(0.05
%–1.10
%),
suggesting
anthropogenic
volatile
compounds
(VOCs),
such
those
combustion,
play
a
major
role
formation
urban
aerosols
winter.
In
addition
promoting
aerosol
formation,
could
also
enhance
other
evidenced
significant
correlations
between
tracers
various
tracers.
These
findings
highlight
contributing
heavy
haze.
Scientific Data,
Journal Year:
2025,
Volume and Issue:
12(1)
Published: Jan. 17, 2025
During
the
COVID-19
pandemic
changes
in
human
activity
became
widespread
through
official
policies
and
organically
response
to
virus's
transmission,
which
turn,
impacted
environment
economy.
The
has
been
described
as
a
natural
experiment
that
tested
how
social
economic
disruptions
different
components
of
global
Earth
System.
To
move
this
beyond
hypotheses,
locally-resolved,
globally-available
measures
how,
where,
when
changed
are
critically
needed.
Here
we
use
satellite-derived
nighttime
lights
quantify
map
daily
atypical
for
each
urban
area
globally
two
years
after
onset
using
machine
learning
anomaly
detectors.
Metrics
characterizing
from
pre-COVID
baseline
settlements
quality
assurance
reported.
This
dataset,
TRacking
Anomalous
induced
changEs
NTL
(TRACE-NTL),
is
first
resolve
all
metropolitan
regions
globally,
daily.
It
suitable
support
variety
post-pandemic
studies
assess
impact
environmental
systems.
Photolysis
of
nitrate
(NO3-)
in
the
presence
photosensitizers
is
thought
to
promote
release
atmospherically
important
reactive
nitrogen
species
(NOy),
such
as
HONO,
via
mechanisms
that
are
poorly
understood.
To
address
this
knowledge
gap,
we
conducted
photochemistry
studies
on
mixtures
NO3-,
a
model
photosensitizer
[4-benzoylbenzoic
acid
(4-BBA)],
and
various
aliphatic
organic
matter
proxies.
We
found
enhances
production
NOy
superoxide
(O2-)
from
bulk
aqueous
photolysis,
while
addition
4-BBA
decreases
O2-
yields
most
cases.
This
effect
was
not
observed
heterogeneous
systems,
where
enhanced
photochemical
when
coadsorbed
with
NO3-
silica
surfaces.
demonstrates
act
both
oxidants
reductants,
regulating
oxygen
photochemistry.
Given
sufficient
residence
time
phase,
photoproducts
can
be
scavenged
secondary
reactions
photosensitizers.
In
aerosol
systems
high
surface
area-to-volume
ratios,
however,
volatilization
favored,
less
affected
by
chromophoric
sinks
phase.
work
intricate
role
moieties
natural
conversion
(i.e.,
renoxification)
atmosphere.
The
photochemical
loss
of
VOCs
induced
by
OH
radicals
has
been
proven
to
be
important
for
diagnosing
ozone
formation
chemistry,
while
chlorine
chemistry
is
becoming
increasingly
critical
in
the
atmosphere
oxidizing
primary
pollutants
and
accelerating
secondary
pollutants.
However,
role
consumed
caused
not
clear.
Here,
observations
combined
with
model
simulations
suggest
that
depletion
oxidized
would
only
promote
oxygenated
organic
molecules
(OOMs)
but
also
help
explain
nonlinear
between
(O3
OOMs)
precursors
(VOCs
NOx).
This
enhancement
O3
OOMs
nonlinearly
dependent
on
ratio
NOx,
connection
aerosol
VOCs/NOx
provides
insight
into
understanding
oxidation
processes
intermediates
from
emission,
reaction,
products.
Catalysts,
Journal Year:
2025,
Volume and Issue:
15(4), P. 342 - 342
Published: April 1, 2025
The
synthesis
of
nitrate
(NO3−)
via
electrocatalytic
nitric
oxide
oxidation
reaction
(NOOR)
is
a
green
and
efficient
strategy
for
nitrogen
fixation,
which
has
great
advantages
over
conventional
synthesis.
Notably,
it
also
presents
promising
solution
the
remediation
NO
pollutants.
In
this
study,
structure–performance
correlations
α-,
β-,
δ-MnO2
catalysts
were
investigated.
These
three
polymorphs
MnO2
exhibited
disparate
surface
chemistries,
adsorption
capabilities,
NOOR
catalytic
activities.
1.0
M
KOH
electrolyte,
α-MnO2,
characterized
by
its
large-sized
(2
×
2)
one-dimensional
tunnel
structure,
demonstrated
most
outstanding
performance,
achieved
remarkable
NO3−
yield
665.2
mg·h−1·mgcat−1
at
potential
1.9
V,
along
with
excellent
stability
durability.
Furthermore,
Zn-NO
system
was
constructed,
employing
α-MnO2
as
anode
Zn
plate
cathode.
This
innovative
setup
integrated
an
energy
storage
electrochemical
capture,
yielding
production
rate
265.5
mg·h−1·mgcat−1.
density
functional
theory
calculations
confirm
performance
activity
different
crystal
forms
MnO2.
