Document ID: EPA-HQ-OAR-2001-0017-1032
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2006-03-28T05:00Z

Review
of
the
National
Ambient
Air
Quality
Standards
for
Particulate
Matter
Scientific
and
Technical
Background
Briefing
Office
of
Air
and
Radiation,
USEPA
November
8,
2005
2
Overview

We're
nearing
the
completion
of
the
review
of
the
1997
standards
for
particulate
matter

The
decision
is
an
important
one
for
the
nation,
and
must
be
complete
by
September
2006.

This
briefing
will
provide
background
on
how
we
review
air
standards
and
technical
and
scientific
details
on
particles
and
their
health
and
environmental
effects
3
Overview
of
NAAQS
Review
Process

The
Clean
Air
Act
calls
for
national
ambient
air
quality
standards
(
NAAQS)
for
common
air
pollutants,
based
on
the
latest
scientific
criteria

"
Primary"
standards
are
those
`
requisite'
to
`
protect
public
health'
with
an
`
adequate
margin
of
safety;'

"
Secondary"
standards
protect
public
welfare
and
the
environment
(
visibility,
crops,
vegetation,
wildlife,
buildings
&
national
monuments,
climate)

EPA
has
set
NAAQS
for
six
common
air
pollutants:

ground­
level
ozone
(
smog),
particulate
matter,
carbon
monoxide,
lead,

nitrogen
dioxide,
sulfur
dioxide

EPA
considers
only
human
health
and
environmental
effects
in
setting
the
NAAQS

EPA
considers
costs
and
time
to
attain
cleaner
air
in
achieving
the
standards

The
Act
requires
EPA
to
review
the
scientific
criteria
and
these
standards
at
least
once
every
five
years,
with
advice
from
the
Clean
Air
Scientific
Advisory
Committee
(
CASAC)
4
Scientific
studies
related
to
health
and
environmental
effects
EPA
Criteria
Document:

integrative
assessment
of
scientific
studies
EPA
Staff
Paper:

policyrelevant
assessments
leading
to
staff
recommendations
on
standards
Scientific
peer
review
of
published
studies
Reviews
by
CASAC
and
the
public
Reviews
by
CASAC
and
the
public
Public
hearings
and
comments
on
proposal
EPA
proposed
decision
on
standards
EPA
final
decision
on
standards
Interagency
review
We
are
here
PM
NAAQS
Review
­
Process
5

Final
PM
Air
Quality
Criteria
Document 
October
2004

Final
PM
Staff
Paper
 
June
2005

CASAC
letters
and
recommendations
 
June
and
September
2005

Rulemaking
on
PM
NAAQS:

Federal
Register
proposal
to
be
signed
by
December
20,
2005

Public
comment
period:
90
days

Final
Federal
Register
notice
to
be
signed
by
September
27,
2006

Simultaneous
Rulemakings:

°
PM
NAAQS,
FRM,
&
Data
Handling
(
Part
50)

°
Ambient
Air
Monitoring
Regulations:
Requirements
for
Reference
and
Equivalent
Methods,
Network
Design
Requirements
(
Parts
53
&
58)

°
Exceptional
&
Natural
Events
PM
NAAQS
Review
­
Schedule
Web
address
for
Staff
Papers:

http://
www.
epa.
gov/
ttn/
naaqs/
standards/
pm/
s_
pm_
cr_
sp.
html
6
Anatomy
of
a
NAAQS

Four
major
components
of
standards
that
determine
degree
of
protection:


Indicator:
e.
g.,
PM10,
PM2.5,
O3,
SO2

Averaging
Time:
e.
g.,
1­
hr,
24­
hr,

annual
average

Form:
e.
g.,
number
of
exceedances,

percentile,
mean

Level:
e.
g.,
15
µ
g/
m3
7
History
of
Particulate
Matter
NAAQS

1971
 
EPA
promulgates
NAAQS
for
"
total
suspended
particulate"
(
particles
smaller
than
~
25­
45
µ
m
in
diameter)

1987
 
EPA
revises
PM
NAAQS,
changing
the
indicator
from
TSP
to
PM
10
to
focus
on
"
inhalable"

particles
(<
10
µ
m)

1997
 
EPA
revises
PM
NAAQS
to
focus
separately
on
the
"
fine"
and
"
coarse"
fractions
of
PM
10

New
standards
established
for
"
fine"
particles
<
2.5
µ
m
in
diameter
(
PM2.5)

PM10
standards
retained
to
focus
on
"
coarse
fraction"
(
particles
between
2.5
and
10
µ
m
in
diameter)

A
number
of
events
delayed
the
implementation
of
PM2.5.

Industry
organizations
and
state
governments
challenged
EPA
in
the
U.
S.
District
Court.

In
2001,
the
U.
S.
Supreme
Court
upheld
EPA's
authority
under
the
Clean
Air
Act
to
set
standards.

Several
unresolved
issues
were
sent
back
to
the
District
Court.

In
2002,
the
District
Court
rejected
all
remaining
legal
challenges
to
EPA's
1997
standards
for
PM2.5.


2004­
EPA
designated
224
counties,
as
well
as
DC,
as
not
meeting
the
standards
for
PM2.5.


2005­
6
 
Complete
review/
revision
of
PM
NAAQS
(
process
underway)
8
Relative
Mass
0.1
0.3
2.5
1.0
10
100
30
Particle
Diameter,
um
PM2.5
PM10
TSP
Typical
Urban
PM
Size
Distribution
PM10­
2.5
Particle
Diameter,
µ
m
PM10­
2.5
Fine
Particles
Combustion,
gases
to
particles
Sulfates/
acids
Nitrate
Ammonium
Organics
Carbon
Metals
Water
Sources
Coal,
oil,
gasoline,
diesel,
wood
combustion
Transformation
of
SOx,
NOx,
organic
gases
including
biogenics
High
temperature
industrial
processes
(
smelters,
steel
mills)

Forest
fires
Exposure/
Lifetime
Lifetime
days
to
weeks,
regional
distribution
over
urban
scale
to
1000s
of
km
Coarse
Particles
Crushing,
grinding,
dust
Resuspended
dusts
(
soil,
street
dust)
Coal/
oil
fly
ash
Aluminum,
silica,
iron­
oxides
Sea
salt
Tire
wear
Biological
Materials
(
Pollen,
mold,

plant/
insect
fragments)

Sources
Resuspension
of
dust
tracked
onto
roads
Suspension
from
disturbed
soil
(
farms,
mines,
unpaved
roads
Construction/
demolition
Industrial
fugitives
Biological
sources,
sea
spray
Exposure/
Lifetime
Coarse
fraction
(
2.5­
10)
lifetime
of
hours
to
days,
distribution
over
smaller
scales
up
to
100s
km
PM
Components:
fine
and
coarse
9
Public
Health
Risks
of
are
significant
1997
review
found
PM
linked
to:

Premature
death
from
heart
and
lung
disease

Aggravation
of
heart
and
lung
diseases

Hospital
admissions

Doctor
and
ER
visits

Medication
use

School
and
work
absences
 .
all
at
levels
permitted
by
the
old
PM10
NAAQS

And
possibly
to

Lung
cancer
deaths

Infant
mortality

Developmental
problems,
such
as
low
birth
weight,

in
children

Fine
particles
(
PM
2.5
)
appeared
to
present
the
most
significant
risks,
including
10s
of
thousands
of
premature
deaths
10
1997
PM
NAAQS
Decision

New
standards
established
for
PM2.5

"
Generally
controlling"
annual
standard
set
at
15
µ
g/
m3
°
Averaged
over
3
years,
with
allowance
for
spatial
averaging
of
monitors
within
certain
constraints

"
Supplemental"
24­
hour
standard
set
at
65
µ
g/
m3,
to
protect
against
peak
concentrations
that
might
occur
due
to
strong
local
or
seasonal
sources
over
limited
areas
and/
or
time
periods
°
Annual
98th
percentile,
averaged
over
3
years

PM10
standards
were
retained
to
focus
on
"
coarse
fraction"

particles
(
between
2.5
and
10
µ
m)


50
µ
g/
m3,
annual
average

150
µ
g/
m3,
24­
hr
average,
but
form
of
standard
changed
to
99th
percentile
11
PM2.5
and
Ozone
Nonattainment
Areas
Designated
Nonattainment
PM2.5
only*

Both
8­
hour
Ozone
and
PM2.5*

8­
hour
Ozone
Only
*
For
PM2.5,
the
designated
partial
county
areas
are
shown
as
actual
boundaries
designated.
OAQPS,
AQSSD
April
28,
2005
12

Hundreds
of
new
short­
term
exposure
studies

New
outcomes:
physician
visits,
cardiovascular
effects
(
myocardial
infarction,
biomarkers),
and
possibly
developmental
effects

New
multi­
city
and
source
apportionment
studies

Extensive
reanalyses/
validation
and
extended
analyses
of
key
longterm
exposure
studies

New
evidence
of
association
with
lung
cancer
mortality

Intervention
studies
reporting
health
improvement
with
reduction
in
PM
and
gaseous
pollutants

Controlled
human
exposure
studies
and
toxicologic
studies
provide
insights
into
potential
mechanisms

Exposure
studies

Greatly
expanded
risk
assessment

Based
on
data
from
extensive
PM
2.5
monitoring
network
and
results
from
new
health
studies
What's
new
since
1997?
.
.
.
an
unprecedented
number
of
new
studies
13
Staff
recommendations
­
indicator
and
averaging
times

Current
indicator
based
on
mass,
using
size
cutpoint
at
2.5
µ
m

Staff
concludes
that
mass­
based
indicator
remains
appropriate
°
Health
studies
implicate
various
PM
components
(
sulfates,
nitrates,

elemental
carbon,
organic
compounds,
metals)
are
linked
with
adverse
effects
°
Likely
that
different
components
more
closely
linked
with
different
effects
°
No
basis
to
exclude
any
components
°
Staff
emphasizes
need
for
continued
research
on
effects
from
different
PM
components,
PM
from
various
sources,
or
different
size
classes
(
e.
g.,
ultrafine
particles)


Staff
concludes
that
size
cut
of
2.5
µ
m
remains
appropriate

More
completely
captures
fine
particles
under
all
conditions
in
U.
S.,
particularly
under
high
humidity
conditions,
while
recognizing
that
some
small
coarse
particles
may
be
captured

Staff
concludes
that
annual
and
24­
hour
averaging
times
remain
appropriate
14
Staff
recommendations
on
primary
PM2.5
standards

Consideration
should
be
given
to
alternative
suites
of
PM2.5
standards:

An
annual
standard
at
the
current
level
of
15
µ
g/
m3
together
with
a
revised
24­
hour
PM
2.5
standard
in
the
range
of
35
to
25
µ
g/
m3,
based
on
a
98th
percentile
form
for
a
standard
set
at
the
middle
to
lower
end
of
this
range,
or
a
99th
percentile
form
for
a
standard
set
at
the
upper
end
of
this
range
OR

A
revised
annual
PM
2.5
standard,
within
the
range
of
14
to
12
µ
g/
m3,
together
with
a
revised
24­
hour
PM
2.5
standard
in
the
range
of
40
to
30
µ
g/
m3.
Staff
judges
that
a
suite
of
standards
that
includes
either
the
annual
or
24­
hour
standard,
or
both,
set
at
the
middle
to
lower
end
of
these
ranges
could
provide
an
appropriate
degree
of
health
protection
15
CASAC
recommendations
on
primary
PM2.5
standards

CASAC
found
staff
recommendations
"
scientifically
well­
reasoned"

and
advised
that
primary
PM2.5
standards
should
be
revised
"
to
provide
increased
public
health
protection"

Consensus
in
agreement
with
staff
recommendations
that
focused
primarily
on
lowering
the
24­
hr
PM
2.5
standard
°
In
addition,
Panel
"
did
not
endorse
the
option
of
keeping
the
annual
standard
at
its
present
level"

Most
Panel
members
favored
a
24­
hr
standard
in
the
range
of
35
to
30
µ
g/
m3
together
with
a
revised
annual
standard
in
the
range
of
14
to
13
µ
g/
m3

Most
Panel
members
favored
continued
use
of
98th
percentile
form,

along
with
continued
use
of
annual
and
24­
hour
averaging
times
16
Staff/
CASAC
recommendations
for
secondary
PM
NAAQS
to
address
visibility
impairment

Staff
recommends
revising
current
standards
to
provide
increased
and
more
targeted
protection
primarily
in
urban
areas
from
visibility
impairment
related
to
fine
particles

Staff
recommends
that
a
revised
secondary
standard
consider:

An
averaging
time
of
4
to
8
daylight
hours

A
level
in
the
range
of
30
to
20
µ
g/
m3,
depending
in
part
on
the
form
of
the
standard

A
percentile­
based
form,
focusing
on
a
range
from
the
92nd
to
the
98th
percentile
of
the
annual
distribution
of
daily
short­
term
PM
2.5
concentrations,
averaged
over
3
years

CASAC
panel
members
recommended
considering
a
92nd
to
98th
percentile
form,
combined
with
a
level
toward
the
upperend
of
the
proposed
range
of
30
to
20
µ
g/
m3

Decision
on
secondary
linked
to
decision
on
health
based
NAAQS
17
Basis
for
1997
decisions
on
PM10
standards
.

.
.
built
upon
earlier
PM
NAAQS
reviews

1971:
set
NAAQS
for
"
total
suspended
particulate"
(
particles
smaller
than
~
25­
45
µ
m
in
diameter)

1987:
revised
PM
NAAQS,
changing
the
indicator
from
TSP
to
PM10
to
focus
on
"
inhalable"
or
"
thoracic"
particles
(<
10
µ
m)

Crustal
materials,

road
dust,
dirt,

biologicals
Sulfates,
nitrates,
ammonium,

elemental
carbon,
organics,

metal
compounds
Extra­
thoracic
Combustion,

atmospheric
reactions
thoracic
Sulfates,
nitrates,
ammonium,

elemental
carbon,
organics,

metal
compounds
Crustal
materials,

road
dust,
biological
materials
Fine
Particles
Coarse
Particles
"
Bimodal"
Distribution
of
Ambient
PM:
Particle
Deposition
in
Humans:
18
Concentration
ug/
m3
Meets
Does
Not
Meet
Note:
Based
on
AQS
data
as
of
July
8,
2005.
Excludes
Regionally­
concurred
flagged
values.

County­
level
status
for
PM10
NAAQS,
2002­
2004
based
on
24­
hour
standard
only
(
150
ug/
m3,
1
expected
exceedence)

Preliminary
draft
19

In
conjunction
with
new
PM2.5
standards,
generally
strong
public
and
CASAC
support
for
retaining
standards
to
protect
against
the
effects
of
coarse
fraction
particles
(
PM10­
2.5)


Dosimetry
evidence
shows
deposition
in
lower
respiratory
tract

Limited
PM10
short­
term
exposure
studies
linked
coarse
fraction
particles
to
respiratory
effects

Possible
long­
term
exposure
effects
considered
based
on
potential
build­
up
in
the
lung

PM10
retained
as
indicator

Only
health
studies
of
clear
relevance
used
PM10
in
areas
where
coarse
fraction
was
dominant

Very
limited
PM10­
2.5
air
quality
data;
but
extensive
PM10
data

Both
24­
hr
and
annual
PM10
standards
retained
at
same
levels

Only
evidence
from
2
studies
in
areas
that
exceeded
current
standards

Form
of
24­
hr
standard
revised
to
a
concentration­
based
form
(
99th
percentile),
to
retain
generally
equivalent
level
of
protection

Court
found
"
ample
support"
for
decision
to
regulate
coarse
particles,
but
.
.
.


Vacated
revision,
finding
PM10
to
be
a
poorly
matched
indicator
for
coarse
fraction
particles
because
it
includes
fine
particles
1997
Decision
on
PM10
NAAQS
20
Current
review:

approach
based
on
new
information

Focus
on
new
information
indexed
by
PM
10­
2.5

Growing,
but
still
limited,
body
of
PM10­
2.5
epidemiologic
evidence

Much
more
PM10­
2.5
air
quality
data

New
studies
report
statistically
significant
associations
between
short­
term
exposure
to
PM
10­
2.5
and
morbidity,

including
hospitalization
and
respiratory
symptoms

Magnitudes
of
associations
similar
to
those
for
PM2.5,
but
generally
less
precise
estimates,
likely
due
to
increased
exposure
measurement
error
21
Results
of
US
and
Canadian
time­
series
epidemiologic
studies,
in
order
of
high
to
low
precision
from
left
to
right
in
each
health
outcome
group.
(
PM
Staff
Paper
Figure
3­
2)

U.
S.
and
Canadian
studies
of
associations
between
short­
term
PM
exposure
and
mortality
22
U.
S.
and
Canadian
studies
of
associations
between
short­
term
PM
exposure
and
morbidity
Results
of
US
and
Canadian
time­
series
epidemiologic
studies,
in
order
of
high
to
low
precision
from
left
to
right
in
each
health
outcome
group.
(
PM
Staff
Paper
Figure
3­
2)
23
Considerations
in
defining
an
indicator
for
thoracic
coarse
particles

Most
obvious
choice
is
size­
differentiated,
mass­
based
indicator
used
in
epidemiologic
studies,
PM10­
2.5

Upper
size
cut
consistent
with
dosimetric
evidence

Lower
size
cut
consistent
with
choice
of
PM2.5
for
fine
particles

Insufficient
information
available
to
define
an
indicator
solely
in
terms
of
other
metrics,
such
as
specific
components

Available
epidemiologic
evidence
quite
limited
and
with
large
uncertainties,
reflective
of
more
heterogeneous
spatial
distribution
and
chemical
composition

Evidence
for
focus
on
coarse
particles
common
in
urban
environments

Toxicologic
evidence
suggests
effects
with
several
components
of
particles
typical
of
urban
areas
(
e.
g.,
road
dust
particles),
but
not
particles
of
geologic
origin
(
e.
g.,
Mt.
St.
Helens
dust)


Epidemiologic
studies
(
e.
g.,
Spokane)
find
no
association
between
mortality
and
PM10
from
wind
storms
(
when
natural
crustal
particles
predominate)


Lack
of
epidemiologic
evidence
related
to
thoracic
coarse
particles
typical
of
non­
urban
areas
24
Considerations
in
defining
an
indicator
(
cont.)

Also
considered
evidence
related
to
coarse
particles
in
communities
predominantly
influenced
by
agricultural
or
mining
activities

Absence
of
evidence
at
community­
level
exposures
(
in
contrast
to
effects
reported
at
occupational
exposure
levels)


Unlikely
to
be
contributing
to
effects
observed
in
recent
urban
studies

Clear
distinctions
noted
in
the
nature
of
coarse
particles
found
in
urban
and
non­
urban/
rural
areas,
leading
to
consideration
of
more
narrowly
defined
indicator
that
focuses
on
particles
characteristic
of
sources
generally
present
in
urban
areas

Higher
exposures
in
urban
than
in
near­
by
rural
areas,
due
to
local
urban
sources
(
resuspended
dust
from
high
traffic­
density
paved
roads;
industrial
sources)


Urban
coarse
particles
enriched
by
contaminants
(
e.
g.,
metals,
other
air
toxics)
not
commonly
found
in
natural
geologic
crustal
materials
typical
of
rural
particles

Staff
concludes
that,
given
differences
in
composition
and
effects
evidence,
it
is
not
appropriate
to
assume
that
effects
related
to
the
mix
of
coarse
particles
commonly
found
in
urban
environments
would
also
apply
to
particles
characteristic
of
rural
areas
25
Coarse
Particle
Composition
0
5
10
15
20
25
USC
BHM
CTR
ATL
YRK
Concentration,

ug/

m3
unknown
EC
OCM
Crustal
Sulfates
Nitrates
Average
PM
10­
2.5
composition
for
Los
Angeles
and
two
eastern
urban­
rural
pairs.
Based
on
USC
Supersite
data
(
10/
2002
to
9/
2003),
and
Birmingham,
AL
(
BHM,
urban),
Centerville,
AL
(
CTR,
rural),
Atlanta,
GA
(
ATL,
urban)
and
Yorkville,
GA
(
TRK,
rural)
monitoring
sites
in
the
Southeastern
Aerosol
Research
and
Characterization
(
SEARCH)
Study,
4/
2003­
12/
2003.
In
general,
urban
coarse
particles
have
higher
concentrations
and
more
components
from
urban
sources
such
as
combustion
and
industrial
activities
than
rural
sites.
Western
sites
also
show
higher
crustal
contributions.
26
Considerations
in
recommending
ranges
of
levels

Evidence
of
effects
associated
with
short­
term
exposure
to
thoracic
coarse
particles:
morbidity

Significant
associations
reported
with
respiratory
or
cardiovascular
hospitalization
in
areas
(
e.
g.,
Detroit,
St.
Louis,

Seattle)
with
98th
percentile
PM
10­
2.5
values
in
the
range
of
30­
40
µ
g/
m3

Uncertainty
in
population
exposure
characterized
by
ambient
PM
10­
2.5
levels
°
Greater
spatial
variation
in
PM
10­
2.5
concentrations
(
than
for
PM
2.5
)

influences
interpretation
of
epidemiologic
study
results
as
a
basis
for
recommending
standard
levels
°
Detroit
example
°
Time­
series
study
used
PM
10­
2.5
concentrations
obtained
from
Windsor
monitors
°
PM
data
well­
correlated
with
other
Detroit
monitors,
but
analysis
suggests
that
Windsor
levels
are
generally
less
than
half
the
levels
recorded
at
urban­
center
Detroit
monitors,

though
more
similar
to
suburban
areas
well
outside
the
city
27
Considerations
in
recommending
ranges
of
levels
(
cont.)

Evidence
of
effects
associated
with
short­
term
exposure
to
thoracic
coarse
particles:
mortality

Associations
with
mortality
less
consistent
than
with
morbidity;

reported
only
in
areas
with
relatively
high
concentrations
°
Significant
or
nearly­
significant
associations
reported
in
several
areas
(
Steubenville,
Phoenix,
Coachella
Valley)
where
98th
percentile
PM
10­

2.5
values
ranged
from
53
to
107
µ
g/
m3
°
No
significant
associations
reported
in
a
number
of
areas
where
98th
percentile
PM
10­
2.5
values
were
generally
below
50
µ
g/
m3

Uncertainty
in
interpreting
PM
10­
2.5
levels
in
epidemiologic
studies
remains,
as
in
morbidity
studies
°
Coachella
Valley
example
°
Monitor
in
one
community
with
highest
levels
was
used
in
study,

although
a
portion
of
study
population
likely
experienced
appreciably
lower
exposure
levels
°
PM
10­
2.5
measurements
used
in
epidemiologic
study
appear
to
represent
concentrations
at
the
high
end
of
levels
for
communities
in
the
Coachella
Valley
28
Considerations
in
recommending
ranges
of
levels
(
cont.)

Based
on
close
look
at
epidemiologic
studies,
evidence
suggests
consideration
down
to
at
least
50
µ
g/
m3

Recognizes
that
exposure
measurement
error
is
potentially
quite
large

Consideration
of
lower
levels,
to
provide
a
margin
of
safety
against
morbidity
effects
that
may
possibly
occur
at
such
low
levels,
may
not
be
warranted

An
even
more
cautious
or
restrained
approach
to
interpreting
epidemiologic
evidence
led
to
staff
consideration
of
a
standard
that
would
provide
generally
"
equivalent"
protection
to
that
afforded
by
current
standards

A
PM10­
2.5
level
of
approximately
60
µ
g/
m3
(
98th
percentile
value)
would
be
roughly
equivalent
on
average
to
a
PM10
level
of
150
µ
g/
m3
(

oneexpected
exceedence
form)


Comparison
of
areas
that
would
likely
not
meet
possible
alternative
standards
indicates
that
a
PM10­
2.5
standard
of
about
65­
70
µ
g/
m3
(
98th
percentile
form)
would
likely
provide
protection
for
approximately
the
same
number
of
counties
or
number
of
people
as
the
current
PM10
standards
29
Staff
recommendations
based
on
initial
CASAC
advice

Replace
PM10
indicator
with
a
more
narrowly­
defined
indicator
of
urban
thoracic
coarse
particles,
UPM10­
2.5

Primarily
based
on
particle
size,
but
also
on
recognition
that
coarse
particles
from
urban­
type
sources
have
been
associated
with
health
effects

Would
not
include
particles
generally
present
in
rural
areas
typically
characterized
by
high
proportions
of
natural
geologic
materials
(
e.
g.,

windblown
dust;
coarse
particles
from
mining
or
agricultural
operations)

Specify
minimum
monitoring
network
design
requirements
and
exceptional/
natural
events
rule
consistent
with
intent
of
new
indicator

Alternative
levels
for
a
24­
hour
standard
of
approximately
50
to
85
µ
g/
m3
(
depending
in
part
on
the
form
of
the
standard)


More
precautionary
approach
would
focus
on
lower
end
of
range
taking
into
account
levels
reported
in
epidemiologic
studies

Placing
more
weight
on
uncertainties
would
focus
on
upper
end
of
range

Little
basis
for
retaining
an
annual
standard
30
Final
CASAC
advice
(
September
15,
2005
letter)

Panel
found
Staff
Paper
to
be
responsive
to
previous
advice

Committee
agrees
with
summary
of
scientific
data

Several
studies
provide
convincing
data
of
associations
with
morbidity
endpoints;
mortality
associations
suggestive

Coarse
particles
in
urban
or
industrial
areas
are
likely
to
be
enriched
by
anthropogenic
pollutants
inherently
more
toxic
than
windblown
crustal
material

Most
concurred
that
scarcity
of
data
on
rural
toxicity
makes
it
necessary
to
base
standard
on
known
toxicity
of
urban­
derived
coarse
particles

While
data
are
limited
"
several
US
and
Canadian
studies
do
provide
convincing
data
that
there
is
an
association
between
short­
term
exposure
to
PM10­
2.5
and
various
morbidity
endpoints.
Associations
with
mortality
endpoints
were
suggestive
but
not
as
convincing"

General
concurrence
among
Panel
members
on
the
need
for
a
standard
for
particles
between
2.5
and
10
µ
m
(
17
of
17
members)


Supports
24­
hour
averaging
time;
agrees
that
annual
standard
not
warranted

Strongly
recommends
use
of
98th
percentile
form

Most
but
not
all
Panel
members
support
an
urban­
oriented
indicator

Considered
as
a
surrogate
for
urban­
type
components
that
differ
in
composition
from
natural
crustal
particles;
research
needed

However,
some
recommended
a
PM10­
2.5
indicator
accompanied
by
monitoring
and
exceptional­
events
guidance
to
emphasis
urban
influences

Agreement
that
staff
presented
reasonable
justification
for
range
of
levels

Most
members
favored
levels
at
upper
end
of
range

Several
supported
lower
end
of
range
31
Potential
Implementation
Schedules
32
Timelines
if
PM2.5
NAAQS
are
revised
Up
to
April
2019
/
April
2020
April
2014
(
based
on
2011­
2013
data)
/
April
2015
(
based
on
2012­

2104
data)

April
2012
/
April
2013
April
2009
/
April
2010
Nov.
2008
/
Nov.
2009
Nov.
2007
2004­
2006
Nov.
2006
2006
PM
2.5
Primary
NAAQS
Up
to
April
2015
Attainment
Date
with
Extension
Jan.
2009
(
Phase
I
NOx)

Jan.
2010
(
Phase
I
SOx)

Jan.
2015
(
Phase
2
­
NOx
and
SOx)

April
2010
(
based
on
2007­
2009
data)

Attainment
Date
Sept.
2006
April
2008
SIPs
Due
April
2005
Effective
Date
of
Designations
Dec.
2004
Final
Designations
Signature
Feb.
2004
State
Recommendations
to
EPA
2001­
2003
Monitoring
Data
Used
for
State
Recommendations
March
2005
July
1997
Promulgation
of
Standard
CAIR
1997
PM
2.5
Primary
NAAQS
Milestone
33
Timeline
if
PM10­
2.5
Standard
is
adopted*

Up
to
July
2022­
23
July
2017­
18
(
based
on
2014­
2016
data)

July
2015­
16
July
2012­
13
May
2012­
13
July
2011­
12
2008/
9­
2011
Nov.
2006
2006
PM10­
2.5
NAAQS
Attainment
Date
with
Extension
Attainment
Date
SIPs
Due
Effective
Date
of
Designations
Final
Designations
Signature
State
Recommendations
to
EPA
Monitoring
Data
Used
for
State
Recommendations
Effective
date
of
Standard
Milestone
*
Schedule
based
on
monitor
deployment
in
2007
or
08