Journal of Geophysical Research Atmospheres,
Год журнала:
2022,
Номер
127(16)
Опубликована: Авг. 9, 2022
Abstract
Brown
carbon
(BrC)
has
been
recognized
as
an
important
contributor
to
global
warming
due
its
absorption
of
solar
radiation
with
strong
wavelength
dependence.
While
early
studies
mostly
consider
biomass
burning
a
major
emission
source,
few
recent
have
suggested
coal
combustion
and
vehicle
exhaust
contributors
BrC
emissions.
Considering
dominant
consumption,
large
residential
biofuel
usage,
the
increasing
number
vehicles,
pollution
could
result
in
remarkable
regional
climate
effects
China.
This
study
gives
overview
sources,
chemical
composition
properties
BrC,
focusing
on
categorization
measurement
techniques.
The
basic
features
China,
including
surface
concentrations,
column
burden,
sources
associated
absorbing
are
then
summarized
compared
other
countries.
emissions
well
optical
at
365
nm
from
primary
China
also
provide
more
straightforward
understanding
light‐absorbing
With
detailed
comparison
existing
publications,
deeper
insight
into
uncertainties
measurements
will
improve
effect
BrC.
review
recommends
key
research
areas
for
further
investigation
future.
Environment International,
Год журнала:
2022,
Номер
165, С. 107344 - 107344
Опубликована: Июнь 11, 2022
Atmospheric
PAHs
(polycyclic
aromatic
hydrocarbons)
and
their
derivatives
are
a
global
concern
that
influences
environments
threatens
human
health.
Concentrations
of
52
the
main
in
six
Chinese
megacities
were
measured
winter
2019.
The
concentrations
∑PAHs
(sum
PAHs)
ranged
from
19.42
±
7.68
to
65.40
29.84
ng
m-3,
with
significantly
higher
levels
northern
cities
(Harbin
[HB],
Beijing
[BJ],
Xi'an
[XA])
than
southern
ones
(Wuhan
[WH],
Chengdu
[CD]
Guangzhou
[GZ]).
Source
apportionment
was
conducted
by
PMF
model
results
showed
coal
combustion
traffic
emissions
two
dominant
sources,
which
dominated
cities,
respectively.
Biomass
burning
also
characterized
as
crucial
source
extremely
high
contributions
XA
(42.5%).
Assisted
individual
PAH
results,
source-depend
TEQ
(total
BaP
equivalent)
incremental
lifetime
cancer
risk
(ILCR)
firstly
reported
these
cities.
highlighted
biomass
both
ILCR,
underestimated
apportionment.
Secondary
organic
aerosol-derived
demonstrated
increase
compared
fresh
three
parameters,
namely
temperature,
relative
humidity,
O3
multiple
linear
regression
principal
factors
influencing
secondary
reactions
winter.
This
study
provides
accurate
health-orientated
potential
control
measures
mitigate
toxicity
formed
PAHs,
decrease
uncertainty
level
traditional
methods.
revealed
great
progress
air
pollution
government
past
20
years,
but
still
long
way
go
formulate
strict
emission
strategies
environmental
health-protective
perspectives.
Environmental Science & Technology,
Год журнала:
2024,
Номер
unknown
Опубликована: Фев. 23, 2024
Particulate
brown
carbon
(BrC)
plays
a
crucial
role
in
the
global
radiative
balance
due
to
its
ability
absorb
light.
However,
effect
of
molecular
formation
on
light
absorption
properties
BrC
remains
poorly
understood.
In
this
study,
atmospheric
samples
collected
from
six
Chinese
megacities
winter
and
summer
were
characterized
through
ultrahigh-performance
liquid
chromatography
coupled
with
Orbitrap
mass
spectrometry
(UHPLC-Orbitrap
MS)
measurements.
The
average
values
coefficient
at
wavelength
365
nm
(babs365)
approximately
4.0
times
higher
than
those
summer.
Nitrogen-containing
organic
molecules
(CHNO)
identified
as
critical
components
light-absorbing
substances
both
seasons,
underscoring
importance
N-addition
BrC.
These
nitrogen-containing
chromophores
more
closely
related
nitro-containing
compounds
originating
biomass
burning
nitrogen
oxides
(NOx)/nitrate
(NO3–)
reactions
winter.
summer,
they
reduced
N-containing
formed
ammonia
(NH3)/ammonium
(NH4+)
reactions.
NH3/NH4+-mediated
contributed
secondary
winter,
particularly
southern
cities.
Compared
O/Cw,
lower
molecule
conjugation
indicator
(double
bond
equivalent,
DBE),
babs365
suggest
possible
bleaching
mechanism
during
oxidation
process.
findings
strengthen
connection
between
composition
BrC,
providing
insights
into
mechanisms
across
northern
cities
different
seasons.
