Atmospheric chemistry and physics,
Journal Year:
2024,
Volume and Issue:
24(18), P. 10409 - 10424
Published: Sept. 19, 2024
Abstract.
Aviation
soot
surrogates
processed
in
contrails
are
believed
to
become
potent
ice
nuclei
at
cirrus
temperatures.
This
is
not
verified
for
real
aviation
soot,
which
can
have
vastly
different
physico-chemical
properties.
Here,
we
sampled
particles
from
in-use
commercial
aircraft
engines
and
quantified
the
effect
of
contrail
processing
on
their
nucleation
ability
T<
228
K.
We
show
that
becomes
compacted
upon
processing,
but
does
change
contrast
other
types.
The
presence
H2SO4
condensed
pores,
highly
fused
nature
primary
arrangement
what
limit
volume
pores
generated
turn
limiting
sites
nucleation.
Furthermore,
hypothesized
contrail-processed
emitted
alternative
jet
fuel
would
also
be
poor
ice-nucleating
if
emission
sizes
remain
small
(<
150
nm).
ACS Earth and Space Chemistry,
Journal Year:
2021,
Volume and Issue:
5(12), P. 3499 - 3510
Published: Nov. 23, 2021
The
prediction
of
ice
cloud
formation
in
the
atmosphere
remains
challenging.
Free
tropospheric
aerosols
can
act
as
nucleating
particles,
affecting
properties
and
precipitation.
physicochemical
free
particles
are
modified
upon
long-range
transport
by
different
atmospheric
processes.
These
modifications
affect
potential
individual
particles.
We
investigated
collected
at
remote
Pico
Mountain
Observatory
2225
m
a.s.l.
North
Atlantic
Ocean
using
multimodal
micro-spectroscopy
chemical
imaging
techniques.
probed
their
nucleation
(IN)
activity
an
IN
stage
interfaced
with
environmental
scanning
electron
microscope.
Retroplume
analysis,
imaging,
analysis
indicated
that
size-resolved
composition,
mixing
state,
phase
state
similar
aging
times
but
patterns
were
substantially
different.
Relative
humidity-dependent
glass-transition
temperatures
estimated
from
meteorological
conditions
consistent
observed
organic
component
particles'
phase.
More
viscous
(solid
semi-solid-like)
more
active
deposition
mode
ranging
205
to
220
K
than
less
This
study
provides
a
better
understanding
transported
role
formation.
Environmental Science Atmospheres,
Journal Year:
2023,
Volume and Issue:
3(12), P. 1693 - 1740
Published: Jan. 1, 2023
The
effects
of
aviation's
non-CO
2
emissions
on
climate
and
air
quality
are
complex
relatively
poorly
understood.
Mitigation
measures
need
to
be
very
carefully
considered
so
that
perverse
outcomes
do
not
result.
Atmospheric chemistry and physics,
Journal Year:
2024,
Volume and Issue:
24(3), P. 2045 - 2058
Published: Feb. 16, 2024
Abstract.
The
radiative
characteristics
and
lifetimes
of
contrails
are
dependent
on
the
number
concentration
ice-forming
particles
in
engine
exhaust
plume.
Aircraft
gas
turbine
engines
produce
a
variety
particles,
yet
it
is
understood
that
non-volatile
black
carbon
aggregates
dominant
source
with
typical,
fossil-derived
jet
fuel.
However,
cleaner
combustion
technologies
adoption
alternative
fuels
(e.g.
hydrogen
or
synthetic
aviation
fuel),
particle
emissions
expected
to
decrease
even
be
eliminated.
Under
these
conditions,
contrail
properties
will
depend
upon
other
than
carbon.
Ultrafine
(<
100
nm)
lubrication
oil
droplets
constitute
significant
fraction
total
organic
particulate
matter
released
by
aircraft;
however,
their
ability
form
ice
crystals
has
hitherto
been
unexplored.
In
this
work,
we
experimentally
investigate
activation
freezing
behaviour
using
an
expansion
chamber,
assessing
potential
as
particles.
We
generate
geometric
mean
mobility
diameter
(100.9
±
0.6)
nm
show
activate
water
droplets,
which
subsequently
freeze
when
temperature
below
∼
235
K.
find
nucleation
should
considered
future
computational
studies
–
particularly
under
soot-poor
conditions
would
benefit
from
size
distribution
measurements
at
cruise
altitude.
Overall,
taking
steps
reduce
help
climate
impact
cirrus.
Abstract
Fully
accounting
for
the
climate
impact
of
aviation
requires
a
process-level
understanding
aircraft
soot
particle
emissions
on
formation
ice
clouds.
Assessing
this
with
help
global
models
remains
elusive
and
direct
observations
are
lacking.
Here
we
use
high-resolution
cirrus
column
model
to
investigate
how
aircraft-emitted
particles,
released
after
crystals
sublimate
at
end
lifetime
contrails
contrail
cirrus,
perturb
cirrus.
By
allying
cloud
simulations
measurement-based
description
soot-induced
formation,
find
that
only
small
fraction
(<1%)
particles
succeeds
in
forming
alongside
homogeneous
freezing
liquid
aerosol
droplets.
Thus,
soot-perturbed
homogeneously-formed
fundamentally
do
not
differ
optical
depth.
Our
results
imply
estimates
radiative
forcing
from
interactions
between
large-scale
may
be
overestimates.
The
improved
scientific
reported
here
provides
process-based
underpinning
parametrizations
targeted
field
observations.
Atmospheric chemistry and physics,
Journal Year:
2021,
Volume and Issue:
21(23), P. 17267 - 17289
Published: Nov. 30, 2021
Abstract.
A
global
aerosol–climate
model,
including
a
two-moment
cloud
microphysical
scheme
and
parametrization
for
aerosol-induced
ice
formation
in
cirrus
clouds,
is
applied
order
to
quantify
the
impact
of
aviation
soot
on
natural
clouds.
Several
sensitivity
experiments
are
performed
assess
uncertainties
this
effect
related
(i)
assumptions
nucleation
abilities
soot,
(ii)
representation
vertical
updrafts
(iii)
use
reanalysis
data
relax
model
dynamics
(the
so-called
nudging
technique).
Based
results
simulations,
radiative
forcing
from
soot–cirrus
range
−35
13
mW
m−2
quantified,
depending
assumed
critical
saturation
ratio
active
fraction
but
with
confidence
level
below
95
%
several
cases.
Simple
idealized
prescribed
velocities
further
show
that
aspect
investigated
could
potentially
add
factor
about
2
uncertainty
estimates
resulting
forcing.
The
technique
proved
essential
identify
statistically
significant
signal
internal
variability,
while
simulations
free-running
mode
sea-surface
temperatures
sea-ice
concentrations
shown
be
unable
provide
robust
effect.
comparison
analogous
studies
very
large
diversity,
conspicuous
lack
consensus
across
various
estimates,
which
points
need
more
in-depth
analyses
roots
such
discrepancies.
Aerosol Science and Technology,
Journal Year:
2022,
Volume and Issue:
56(8), P. 732 - 743
Published: April 29, 2022
High-throughput,
laboratory
units
for
generation
of
aircraft-like
soot
are
needed
to
quantify
and
understand
the
impact
such
emissions
on
public
health
climate
change
due
high
costs
limited
access
aircraft
engines.
Enclosed
spray
combustion
jet
fuel
is
used
here
generate
concentrations,
up
255
mg/m3,
three
orders
magnitude
higher
than
those
typically
obtained
by
widely
generators
that
use
vapor-fed
flames.
This
attributed
mostly
real
fuels.
The
large
mass
concentrations
enable
routine
characterization
specific
surface
area
(SSA)
pore
size
distribution
(PSD)
N2
adsorption.
geometric
mean
mobility
diameter,
d¯m,
agglomerates
was
systematically
varied
from
15
180
nm
varying
equivalence
ratio
(EQR)
at
constant
feed
rates,
while
organic
total
carbon
(OC/TC)
low
(<20%)
all
conditions.
primary
particle
(PP)
d¯p,
standard
deviation,
σg,p,
mass-mobility
exponent,
Dfm,
were
hardly
altered
in
EQR
range.
These
measured
Dfm
σg,p
indicate
PPs
sinter-bonded
growth,
agreement
with
literature.
Most
importantly,
made
≤
1.34
has
mainly
small
pores
(<2
nm)
similar
morphology
(Dfm
=
2.52
±
0.17),
SSA
(160
−
239
m2/g),
OC/TC
(<
20%),
d¯m
(15
61
d¯p
(14
high-thrust
emissions.
Journal of Geophysical Research Atmospheres,
Journal Year:
2022,
Volume and Issue:
127(22)
Published: Nov. 16, 2022
Abstract
Soot
particles
are
one
of
the
major
aerosol
components
(in
particle
number
concentration)
in
troposphere
and
can
impact
cirrus
formation.
Depending
on
their
physicochemical
properties,
soot
nucleate
ice
regime
via
pore
condensation
freezing
(PCF)
at
a
lower
saturation
threshold
than
that
homogeneous
solution
droplets.
undergoing
multiple
cloud
cycles
change
its
porosity
surface
wettability,
thus
modulating
PCF
ability.
In
this
study,
organic‐rich
‐lean
size‐selected
propane
flame
were
coated
with
different
thicknesses
sulfuric
acid
(H
2
SO
4
)
exposed
to
thermodynamic
conditions
under
228
K
relative
humidity
respect
water
104%
simulate
contrail
Ice‐activated
from
mimicked
sublimated
before
being
tested
for
nucleation
(IN)
T
≤
233
K.
Additionally,
size
mass
distribution
as
well
morphology
characterized.
The
results
demonstrate
increase
mesopore
availability
induced
by
cloud‐processing
plays
key
role
regulating
IN.
All
cloud‐processed
become
more
compacted,
however,
only
if
relevant
mesopores
generated,
compacted
exhibit
promoted
If
H
coating
and/or
enriched
organics
occupy
volume,
inhibition
is
observed
soot.
Notably,
thick
enhances
400
nm
organic‐lean
because
partially
engulfed
but
collapsed
soot‐core
may
have
new
produced
compaction.
Therefore,
abundance
evaluating
aged
IN
