Atmospheric chemistry and physics,
Год журнала:
2024,
Номер
24(23), С. 13793 - 13810
Опубликована: Дек. 12, 2024
Abstract.
Understanding
the
composition
and
evolution
of
atmospheric
organic
vapors
is
crucial
for
exploring
their
impact
on
air
quality.
However,
molecular
seasonal
characteristics
in
urban
areas,
with
complex
anthropogenic
emissions
high
variability,
remain
inadequately
understood.
In
this
study,
we
conducted
measurements
Beijing
during
2021–2022,
covering
four
seasons,
using
improved
proton-transfer-reaction
mass
spectrometry
(Vocus-PTR-MS).
During
measurement
period,
a
total
895
peaks
were
observed,
512
them
can
be
assigned
to
formulas.
The
contribution
CxHyOz
species
most
significant,
composing
up
54
%
number
74
mixing
ratio
organics.
With
enhanced
sensitivity
resolution,
various
multiple
oxygens
(≥
3)
or
at
level
sub-parts
per
trillion
(ppt)
44
measured
sub-ppt
38
containing
three–eight
oxygen
atoms.
Organic
mainly
consist
intermediate/semi-volatile
compounds,
many
formulae
detected
reported
oxidation
products
volatile
precursors.
summer,
fast
photooxidation
process
generated
led
an
increase
both
proportion,
while,
other
variations
closely
correlated
those
1–2
oxygens,
which
could
substantially
influenced
by
primary
emissions.
low
content
(≤
2
oxygens)
are
comparable
results
obtained
traditional
PTR-MS
neighboring
regions.
Atmospheric chemistry and physics,
Год журнала:
2025,
Номер
25(4), С. 2459 - 2472
Опубликована: Фев. 26, 2025
Abstract.
Volatile
organic
compounds
(VOCs)
play
crucial
roles
in
regulating
the
formation
of
tropospheric
ozone.
However,
limited
knowledge
on
interactions
between
vertical
VOC
variations
and
photochemical
ozone
planetary
boundary
layer
(PBL)
has
hindered
effective
control
strategies,
especially
large
cities.
In
this
study,
we
investigated
changes
concentrations,
compositions,
key
driving
factors
a
suite
VOCs
using
online
gradient
measurements
taken
from
325
m
tall
tower
urban
Beijing.
The
impacts
these
were
also
analyzed
box
model
simulations.
Our
results
indicate
that
exhibited
distinct
variation
patterns
due
to
their
differences
sources
chemical
reactivities,
along
with
diurnal
evolution
PBL.
During
daytime,
reactive
(e.g.,
hydrocarbons)
are
rapidly
oxidized
as
they
mix
upward,
accompanied
by
accumulation
oxygenated
(OVOCs)
middle
upper
layers.
addition,
responds
positively
both
NOx
VOCs.
As
result,
production
rate
declines
height
simultaneous
decreases
concentrations
but
remains
high
strong
aloft
is
primarily
driven
presence
OVOC
concentrations.
Therefore,
careful
consideration
should
be
given
rates
regimes
whole
PBL
when
developing
regional
strategies.
