ACS ES&T Air,
Journal Year:
2024,
Volume and Issue:
1(8), P. 767 - 779
Published: May 21, 2024
Indoor
air
quality
is
critical
to
human
health,
as
individuals
spend
an
average
of
90%
their
time
indoors.
However,
indoor
particulate
matter
(PM)
sensor
networks
are
not
deployed
often
outdoor
networks.
In
this
study,
PM2.5
exposure
investigated
via
2
low-cost
in
Pittsburgh.
The
concentrations
reported
by
the
were
fed
into
a
Monte
Carlo
simulation
predict
daily
for
4
demographics
(indoor
workers,
schoolchildren,
and
retirees).
Additionally,
study
compares
effects
different
correction
factors
on
from
PurpleAir
sensors,
including
both
empirical
physics-based
corrections.
results
show
that
mean
varied
1.5
μg/m3
or
less
when
similar.
When
PM
lower
than
outdoor,
increasing
spent
outdoors
increased
up
3
μg/m3.
These
differences
highlight
importance
carefully
selecting
sites
deployment
value
having
robust
network
with
placement.
Building and Environment,
Journal Year:
2022,
Volume and Issue:
222, P. 109359 - 109359
Published: July 9, 2022
Given
that
many
people
typically
spend
the
majority
of
their
time
at
home,
accurate
measurement
and
modelling
home
environment
is
critical
in
estimating
exposure
to
air
pollution.
This
study
investigates
fate
impact
on
human
outdoor
indoor
pollutants
London
homes,
using
a
combination
sensor
measurements,
pollution
estimated
from
CMAQ-urban
model
mass
balance
models.
Averaged
concentrations
PM2.5,
PM10
NO2
were
14.6,
24.7
14.2
μg
m−3
while
14.4,
22.6
21.4
m−3,
respectively.
Mean
infiltration
factors
particles
(0.6–0.7)
higher
than
those
(0.4).
In
contrast,
loss
rates
found
for
(0.5–0.8
h−1)
compared
(0.1–0.3
h−1).
The
average
kitchen
environments
22.0,
33.7
20.8
with
highest
hourly
(437,
644
136
respectively)
during
cooking
times
(6–7
pm).
Indoor
sources
increased
by
an
26–37%
comparison
background
level
without
sources.
Outdoor
exchange
plays
important
role
reducing
indoors
65–86%
42–65%
NO2.
Indoor Air,
Journal Year:
2022,
Volume and Issue:
32(9)
Published: Sept. 1, 2022
Low-cost
monitors
have
made
it
possible
for
the
first
time
to
measure
indoor
PM2.5
concentrations
over
extended
periods
of
(months
years).
Coupled
with
concurrent
outdoor
measurements,
these
measurements
can
be
divided
into
particles
entering
building
from
outdoors
and
generated
activities.
Indoor-generated
are
not
normally
considered
in
epidemiological
studies,
but
they
health
effects
(e.g.,
passive
smoking
high-temperature
cooking).
We
employed
The
Random
Component
Superposition
(RCS)
regression
model
estimate
infiltration
factors
up
790
000
matched
sites.
median
subgroups
3-state
region
ranged
between
0.22
0.24,
an
interquartile
range
(IQR)
0.13–0.40.
These
allowed
calculation
both
indoor-generated
outdoor-infiltrated
PM2.5.
contributed,
on
average,
46%–52%
total
concentrations.
However,
site-specific
fractional
contribution
sources
near-zero
nearly
100%.
influence
potential
exposures
varied
widely
relative
greatest
occurred
at
low-to-moderate
daily
mean
levels
around
6
μg/m3
was
negligible
>20
μg/m3.
Epidemiological
studies
incorporating
only
estimated
due
ambient
origin
may
benefit
newly
available
knowledge
long-term
particle
The Science of The Total Environment,
Journal Year:
2022,
Volume and Issue:
848, P. 157811 - 157811
Published: Aug. 3, 2022
We
evaluated
diurnal
trends
of
size-resolved
indoor
and
outdoor
fluorescent
biological
airborne
particles
(FBAPs)
their
contributions
to
particulate
matter
(PM)
within
0.5-20
μm.
After
a
ten-week
continuous
sampling
via
two
identical
wideband
integrated
bioaerosol
sensors,
we
found
that
both
PM
were
driven
by
its
component.
Outdoors,
the
median
[interquartile
range]
FBAP
mass
concentration
peaked
at
8.2
[5.8-9.9]
μg/m3
around
sunrise
showed
downtrend
from
6:00
18:00
during
daytime
an
uptrend
night.
The
nighttime
level
was
1.8
[1.4-2.2]
times
higher
than
daytime,
FBAPs
accounted
for
45
%
56
nighttime,
respectively.
Indoors,
rise
in
concentrations
smaller
1
μm
coincided
with
starting
operation
heating,
ventilation,
air
conditioning
(HVAC)
system
6:00,
8:00
dropped
daily
average
noontime.
This
indicated
HVAC
dislodged
overnight
settled
accumulated
fine
bioaerosols
into
environment.
For
larger
μm,
variation
occupancy.
Based
on
regression
modeling,
PM,
non-FBAP,
sources
estimated
be
93
%,
67
97
occupied
period.
Sensors,
Journal Year:
2023,
Volume and Issue:
23(9), P. 4387 - 4387
Published: April 29, 2023
Spatial
variation
of
indoor
and
outdoor
PM2.5
within
three
states
for
a
five-year
period
is
studied
using
regulatory
low-cost
PurpleAir
monitors.
Most
these
data
were
collected
in
an
earlier
study
(Wallace
et
al.,
2022
Indoor
Air
32:13105)
investigating
the
relative
contribution
indoor-generated
outdoor-infiltrated
particles
to
exposures.
About
260
monitors
~10,000
~4000
are
included.
Daily
mean
concentrations,
correlations,
coefficients
divergence
(COD)
calculated
pairs
at
distances
ranging
from
0
(collocated)
200
km.
We
use
transparent
reproducible
open
algorithm
that
avoids
proprietary
algorithms
provided
by
manufacturer
sensors
PA-I
PA-II
The
available
on
API
website
under
name
"PM2.5_alt".
This
validated
several
hundred
separated
up
0.5
spatial
outdoors
homogeneous
with
high
correlations
least
10
km,
as
shown
COD
index
0.2.
There
also
steady
improvement
concentrations
increasing
distance
not
even
<
100
m.
good
agreement
between
located
<100
m
apart
collocated
Federal
Equivalent
Methods
(FEM).
Buildings,
Journal Year:
2024,
Volume and Issue:
14(4), P. 1022 - 1022
Published: April 6, 2024
Ambient
particles
contribute
to
occupant
exposure
as
they
infiltrate
indoor
environments
through
building
envelope
cracks,
impacting
air
quality.
This
study
investigates
the
impact
of
humidity
on
infiltration
ambient
particles,
highlighting
humidity’s
crucial
role
in
influencing
particle
dynamics
environments.
Employing
a
controlled
chamber
system,
we
conducted
experiments
quantify
size-resolved
under
varying
relative
(RH)
conditions.
Both
total
number
and
mass
concentration
increased
with
RH
experimental
chamber.
The
smallest
(0.3–0.4
μm)
experienced
reduced
at
higher
levels
due
hygroscopic
growth,
while
intermediate-sized
showed
infiltration,
resulted
from
coagulation
effects.
Large
(>1.0
demonstrated
factors,
caused
by
lower
penetration
deposition
rates,
minimal
changes.
Our
findings
reveal
that
influences
rate,
process,
thereby
affecting
size
distribution
concentration.
Indoor Environments,
Journal Year:
2024,
Volume and Issue:
1(2), P. 100016 - 100016
Published: May 3, 2024
Multiple
studies
have
considered
socioeconomic
or
ethnic
group
inequities
in
outdoor
fine
particle
(PM2.5)
concentrations.
Due
to
the
lack
of
indoor
measurements,
these
are
forced
assume
that
exposures
directly
related
In
general,
this
assumption
may
be
reasonable,
but
it
is
violated
when
indoor-generated
particles
form
a
substantial
contribution
total
potential
exposure.
We
now
for
first
time
access
long-term
(months
years)
exposures,
made
possible
by
development
low-cost
optical
counters.
A
large
database
4.86
million
hourly
PM2.5
and
concentrations
measured
10,000
>4,000
PurpleAir
monitors
over
5-year
period
(2017-2021)
three
West
Coast
states
(Washington,
Oregon,
California)
has
been
used
compare
with
US
Census
2021
estimates
median
household
income,
educational
attainment,
housing
characteristics,
groups.
Clear
evidence
found
using
as
well
