Document ID: EPA-HQ-OAR-2003-0090-0265
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2004-04-07T04:00Z

M­
1
APPENDIX
M
IMPACT
OF
TRANSPORT
SAN
ANTONIO
EAC
REGION
ATTAINMENT
DEMONSTRATION
MARCH
2004
M­
2
Appendix
M
Table
of
Contents
Transport
into
the
San
Antonio
Region:
Introduction            
M­
3
Analysis
of
Meteorological
Data:
Regional
Haze/
Smoke
Events       
M­
3
Air
Parcels
Paths:
HYSPLIT
model             .      .
M­
7
Analysis
of
Local
Ozone
Levels
and
Selected
Regional
Precursor
Sources  
M­
9
Modeling:
Removing
Anthropogenic
pollution
from
the
Emission
Inventory  .
M­
12
Graphical
Display
of
Data             .          .
M­
19
Ozone
Source
Apportionment
Technology
(
OSAT)
Analysis        ..
M­
23
Conclusion             .             .   .
M­
34
Addendum:
the
State
of
Texas             .        
M­
35
References             .             .   .
M­
36
M­
3
Transport
into
the
San
Antonio
Region:
Introduction
Wind
allows
for
transport
of
air
pollution
over
great
distances.
Through
this
pollution
transport,
even
areas
that
do
not
generate
significant
air
pollution
can
be
affected
by
air
from
other
areas
of
high
pollution
production.
Evidence
for
transport
and
its
effects
on
the
local
San
Antonio
area
are
based
on
two
sources:
archived
meteorological
and
special
event
data
(
which
may
be
local,
state,
national
or
international
in
scope,
and
is
limited
in
time
only
by
the
availability
of
data
archives)
and
local
photochemical
modeling
analysis
(
and
so
is
restricted
to
the
time
and
domain
of
the
specific
modeling
episode).

An
analysis
of
regional
and
national
patterns
helps
provide
an
understanding
of
events
which
may
affect
local
ozone
levels.
Such
patterns
include
meteorological
patterns,
reoccurring
regional
or
distant
events,
and/
or
pollution
patterns
due
to
placement
and
impact
of
regional
pollutant
generators.
Historical
meteorological
data
in
the
San
Antonio
area,
information
on
transport,
wind
speed
and
direction,
air
movement
identified
through
HYSPLIT
back
trajectories,
and
other
important
meteorological
variables
affecting
ozone
concentrations
in
the
San
Antonio
region
are
discussed
in
detail
in
Appendix
A.
Some
of
these
materials
will
be
used
in
the
current
appendix
in
order
to
characterize
the
relationship
between
pollution
transport
into
the
San
Antonio
region
and
high
ozone
readings
locally.

The
other
source
of
analysis
for
this
topic
rests
with
the
1999
CAMx
photochemical
model
used
for
the
attainment
demonstration
in
this
document
set.
While
this
data
set
is
more
limited
in
spatial
extent
and
time
period,
hence
with
restraints
in
generalizability,
it
provides
a
far
richer
context
because
of
the
analytical
tools
available
within
the
CAMx
modeling
tool
chest.

Analysis
of
Meteorological
Data:
Regional
Haze/
Smoke
Events
Significant
regional
haze/
smoke
events
may
affect
the
ozone
levels
in
San
Antonio
from
time
to
time.
In
instances
such
as
these,
fine
particulate
matter
(
PM
2.5)
is
transported
into
the
area.
Transported
PM
2.5
may
impact
local
ozone
readings,
even
if
PM
concentrations
are
well
below
the
NAAQS
for
fine
particulate
matter.
The
Naval
Research
Laboratory's
NAAPS
(
Navy
Aerosol
Analysis
and
Prediction
System)
has
archived
model
results
for
several
pollutants
(
figures
1,
3,
&
4),
displaying
smoke,
dust,
PM
2.5,
and
sulfate
patterns
across
North
America,
aiding
in
pattern
recognition.
(
NAAPS,
2003)

San
Antonio
experienced
high
levels
of
ozone
at
the
same
time
that
heavy
smoke
was
present
during
the
May
1998
Mexico/
Central
America
smoke
event.
This
case
has
been
well
documented
as
a
transport
incident
and
will
be
discussed
for
the
sake
of
comparison
to
a
haze
event
in
September
2002,
during
which
high
levels
of
ozone
were
generated
locally
also.
During
both
events,
San
Antonio
experienced
high
levels
of
PM
2.5
and
had
several
ozone
exceedances.
During
yet
another
smoke
episode
in
May
2002,
lighter
PM
and
smoke
were
accompanied
by
moderate
ozone
readings.

In
May
1998,
a
large
mass
of
smoke
from
agriculture
fires
in
Mexico
and
Central
America
traveled
across
the
state
of
Texas
and
as
far
north
as
the
Dakotas.
EPA
received
requests
from
nine
states
to
exclude
certain
days
of
ozone
data
during
this
episode
from
compliance
calculations.
EPA
reviewed
the
various
requests
in
consultation
with
experts
outside
of
the
EPA,
including
those
from
the
National
Oceanic
and
Atmospheric
Administration
and
the
National
Aeronautics
and
Space
Administration.
The
EPA
did
concur
with
most
of
the
requests
from
those
nine
states.
(
Seitz,
2000)
M­
4
Every
year
the
potential
exists
for
San
Antonio
to
experience
similar
air
quality
events
due
to
agricultural
burning.
In
May
of
2002,
smoke
traveled
from
agricultural
fires
into
Texas.
Figure
M­
1
shows
the
concentration
of
smoke
during
the
May
2002
event.
On
May
9,
Continuous
Air
Monitoring
Station
(
CAMS)
678
in
eastern
San
Antonio
recorded
levels
of
PM
2.5
at
34.62
µ
g/
m
³
and
an
ozone
8­
hour
maximum
of
46
ppb,
neither
of
which
are
considered
high
values.

Figure
M­
1:
Surface
Smoke
Concentration
Levels
for
May
9
&
10,
2002
Source:
The
Naval
Research
Laboratory's
NAAPS,
Navy
Aerosol
Analysis
and
Prediction
System.

The
September
2002
haze
event
was
caused
by
sulfates
transported
from
the
Midwest
(
Ohio
&
Mississippi
Valleys).
(
TCEQ,
2003)
The
San
Antonio
region
experienced
elevated
peak
8­
hr
average
ozone
levels
of
111,
97,
and
92
ppb
on
September
12th,
13th,
and
14th
respectively.
In
addition,
the
regional
background
levels
of
ozone
were
also
elevated
during
these
days.
The
TCEQ
described
the
area's
lowest
peak
eight­
hour
measurement
of
75
ppb
as
a
"
conservative
estimate
of
the
regional
ozone
background
levels,"
based
on
the
September
12,
2002,
CAMS
503
(
Bulverde,
Texas)
readings.
(
TCEQ,
2003b)
The
highest
ozone
reading
on
September
12
was
111
ppb
in
San
Antonio,
measured
at
CAMS
23,
and
was
the
highest
eight­
hour
ozone
average
for
the
region
in
2002.
According
to
TCEQ,
the
"
difference
of
36
ppb
between
the
measured
eight­
hour
area
maximum
of
111
ppb
and
the
estimated
regional
background
level
of
75
ppb
was
likely
caused
by
local
air
pollution
sources
in
the
San
Antonio
area.
The
estimated
36
ppb
local
contribution
was
32
percent
of
the
111
ppb
area
eight­
hour
peak."
(
TCEQ,
2003)
Figure
M­
3
and
Figure
M­
4,
which
follow,
show
the
ground
level
sulfate
concentrations
for
this
event.
M­
5
Figure
M­
2:
Hourly
PM
2.5
and
8­
hr
Average
Ozone
for
San
Antonio,
2002
Ozone
Season
Figure
M­
2
displays
a
comparison
between
PM
2.5
and
ozone
readings
for
the
2002
ozone
season.
The
May
Mexico/
Central
America
smoke
and
September
Ohio
Valley
haze
periods
are
marked
for
reference.
The
highest
eight­
hour
average
ozone
reading
for
2002
was
recorded
at
CAMS
23
on
September
12,
coincident
with
high
PM
2.5
and
sulfate
readings.
The
second,
third
and
fourth
highest
2002
readings
at
CAMS
23
occurred
between
June
17­
24,
when
PM
2.5
readings
were
markedly
lower.

Figure
M­
3.
Ground
Level
Sulfate
Concentrations
on
September
11
&
12,
2002
Source:
The
Naval
Research
Laboratory's
NAAPS,
Navy
Aerosol
Analysis
and
Prediction
System.
0
20
40
60
80
100
120
4/
1/
02
4/
9/
02
4/
17/
02
4/
25/
02
5/
3/
02
5/
11/
02
5/
19/
02
5/
27/
02
6
/
4/
02
6/
12/
02
6/
20/
02
6/
28/
02
7/
6/
02
7/
14/
02
7/
22/
02
7/
30/
02
8/
7/
02
8/
15/
02
8/
23/
02
8/
31/
02
9/
8/
02
9/
16/
02
9/
24/
02
10/
2/
02
10/
10/
02
10/
18/
02
10/
26/
02
Ozone
Season
Days
for
2002
Ozone
(
ppb)

0
5
10
15
20
25
30
35
40
45
PM
2.5
ug/
m3
8­
hr
Ozone
Maximums
PM
2.5
Hourly
Maximums
May
Mex./
Cen.
Amer.
Fires
September
Haze
Event
M­
6
Figure
M­
4.
Ground
Level
Sulfate
Concentrations
on
September
13
&
14,
2002
Source:
The
Naval
Research
Laboratory's
NAAPS,
Navy
Aerosol
Analysis
and
Prediction
System.

The
transport
of
sulfates
from
the
Ohio
Valley
to
Texas
can
be
traced
by
following
the
weather
patterns
at
that
time.
In
the
Northern
Hemisphere,
winds
move
in
a
clockwise
rotation
around
high­
pressure
areas;
thus,
the
position
of
the
high
effects
wind
direction.
The
arrows
show
the
approximate
direction
of
the
winds
with
respect
to
the
high­
pressure
cell
in
Figure
M­
5.
(
TCEQ,
2003c)
The
presence
of
this
cell
moving
across
the
country
from
west
to
east,
driven
by
the
jet
stream,
is
the
most
likely
cause
of
the
pollutant
migration.
Figure
M­
6,
displays
a
progression
of
high
ground­
level
ozone
mass
from
the
Midwest
down
into
Texas
during
the
same
episode.
(
EPA,
2003)

F
igure
M­
5.
High
Pressure
Cell
on
Sept.
7,
2002
and
Same
Cell
on
Sept.
12,
2002
H
H
M­
7
Figure
M­
6.
Regional
Ozone
Concentrations
from
Sep.
7
to
Sep.
14,
2002
Air
Parcels
Paths:
HYSPLIT
model
The
HYSPLIT1
model
provided
an
approximate
path
of
the
air
coming
into
San
Antonio
for
the
September
2002
haze
event
as
shown
in
figures
M­
7
through
M­
9.
Each
back
trajectory2
path
was
computed
for
a
144
hour
(
6
day)
period.

1
The
HYSPLIT
model
runs
described
here
are
based
on
historical
meteorological
data
sets
archived
by
the
National
Centers
for
Environmental
Prediction
within
the
National
Oceanic
and
Atmospheric
Administration.
The
HYSPLIT
model
allows
the
user
to
access
this
archived
data
as
model
input
specific
to
place
and
time.
2
Given
a
geographic
destination
for
an
air
parcel,
back
trajectories
show
the
path
followed
by
the
parcel
before
reaching
the
destination
M­
8
Figure
M­
7.
Back
Trajectories:
Sept.
12,
2002
Figure
M­
8.
Back
Trajectories:
Sept.
13,
2002
Figure
M­
9.
Back
Trajectories:
Sept.
14,
2002
In
conclusion,
the
ozone
levels
recorded
in
San
Antonio
during
mid­
September
2002
coincided
with
high
PM
levels.
There
is
strong
evidence
that
both
the
ozone
and
PM
measured
across
the
local
area
were
part
of
a
wide
pattern
of
transport
across
the
entire
eastern
half
of
the
United
States.
The
May
1998
Mexican
smoke
event
was
considered
M­
9
an
exceptional
event
such
that
the
EPA
excused
local
area
ozone
levels
from
consideration
for
regulatory
purposes,
and
by
definition
was
due
to
transport.
There
is
strong
coincidence
of
HYSPLIT
wind
patterns,
appearance
of
shifting
elevated
ozone
concentrations
archived
by
EPA,
sulfate
concentrations
archived
by
NAAPS,
and
wind
patterns
documented
by
TCEQ
during
the
September
2002
event.
Evidence
of
transport
during
the
September
2002
event,
including
an
analysis
concluding
that
background
levels
in
San
Antonio
reached
as
high
as
75
ppb,
has
been
presented
here.

Analysis
of
Local
Ozone
Levels
and
Selected
Regional
Precursor
Sources
The
HYSPLIT
model
was
also
used
to
estimate
air
parcel
paths
typical
to
ozone
exceedance
days
in
the
San
Antonio
region3
over
a
1997­
2002
period.
By
running
back
trajectories
for
the
forty­
two
exceedance
days
in
the
San
Antonio
region
that
occurred
from
1997
to
2003,
AACOG
staff
identified
wind
patterns
for
exceedance
days.

Figure
M­
104
shows
the
pattern
of
air
parcels
positions
on
their
path
to
the
San
Antonio
International
Airport.
A
total
of
33
hours
for
each
exceedance
day
have
been
backtracked
in
order
to
cover
the
regional
air
quality
modeling
area.
Figure
M­
10
shows
that,
on
high
ozone
days,
it
is
rare
that
air
arriving
in
San
Antonio
will
have
traveled
west,
northwest,
south
or
the
southwest
over
the
six­
year
period
investigated.

Figure
M­
10.
1997­
2002
Pattern
of
Air
Parcels
Paths
Arriving
in
San
Antonio
3
The
HYSPLIT
model
is
used
in
development
of
the
Conceptual
Model;
see
Appendix
A.
4
Because
the
HYSPLIT
model
outputs
both
graphical
and
ASCII­
text
latitude/
longitude/
altitude
coordinate
sets
by
hour,
the
output
is
both
display­
ready
and
suitable
for
further
analysis,
as
performed
to
typify
wind
patterns
associated
with
high
ozone
days.
M­
10
As
mentioned,
the
HYSPLIT
model
back
trajectory
output
provides
hourly
latitude
/
longitude
/
altitude
locations
of
air
parcels.
These
individual
data
points
are
plotted
in
figure
M­
10.
Figure
M­
11
provides
the
percentage
of
air
parcels
allocated
within
each
region
on
the
map.
The
total
for
each
octant
is
located
just
outside
the
250­
mile
circle.

Figure
M­
11.
Back
Trajectories;
Percentages
by
Direction
The
image
shows
that
within
50
miles
of
the
destination
of
the
air
parcels
in
the
back
trajectories,
the
San
Antonio
International
Airport
(
SAIA),
8.5
%
of
the
air
parcels
swept
through
the
northeast,
18.5%
of
the
air
parcels
came
from
the
east,
and
14.2
%
came
from
the
southeast
direction.
It
is
worth
noting
that
the
entire
San
Antonio
Early
Action
Compact
region,
i.
e.,
Bexar,
Comal,
Guadalupe
and
Wilson
Counties,
lies
within
the
50­
mile
radius
shown.

Between
50
and
100
miles
of
SAIA,
0.8%
of
the
air
parcel
came
from
the
west.
On
the
east
of
SAIA,
outside
the
250­
mile
boundary,
the
figure
in
bold
indicates
that
altogether,
26.3%
of
all
air
parcels
came
from
the
east
of
SAIA
within
the
eastern
octant,
where
the
Houston/
Galveston
area
is
located.

Use
of
back
trajectories
to
identify
wind
patterns
coincident
with
high
local
ozone
levels
is
typically
a
technique
used
by
modelers
to
select
new
modeling
episodes,
as
discussed
in
Appendix
A.
These
calculations
show
the
frequency
with
which
air
parcels
pass
through
a
given
region
before
coming
into
San
Antonio
on
a
high
ozone
day.
This,
in
M­
11
turn,
is
important
in
discussing
the
influence
of
ozone
precursor
sources
along
the
back
trajectories
on
ozone
levels
in
the
San
Antonio
region.

Major
Point
Sources
along
Back
Trajectories
on
days
of
High
Ozone
Figure
M­
12
shows
the
location
of
major
point
sources
in
Texas,
identified
by
distance
and
direction
from
San
Antonio
in
the
same
manner
as
the
back
trajectory
air
patterns.
Given
the
predominant
wind
patterns
for
air
arriving
in
San
Antonio
on
high
ozone
days
and
the
location
of
important
point
sources,
it
is
clear
that
air
typically
passes
over
many
of
these
point
sources
prior
to
arriving
in
San
Antonio,
where
high
ozone
levels
are
then
recorded.
In
conclusion,
there
is
a
strong
correlation
between
the
location
of
point
sources
in
Texas
and
air
pathways
associated
with
historical
high
ozone
readings
in
San
Antonio.
This
correlation
is
supported
by
further
analysis
using
the
photochemical
model,
as
now
follows.

Figure
M­
12.
NOx
Point
Sources
in
the
Eastern
Half
of
Texas
by
their
distance,
magnitude
and
direction
from
San
Antonio.
1998;
TCEQ.
M­
12
Modeling:
Removing
Anthropogenic
pollution
from
the
Emission
Inventory
The
evidence
for
transport
can
be
further
demonstrated
by
conducting
a
series
of
modeling
runs
in
which
all
of
the
anthropogenic
emissions
from
the
adjacent
metropolitan
areas
are
removed
from
the
CAMx
emission
inventory
for
the
modeled
episode.
Sensitivity
runs
were
employed
to
determine
the
impact
of
transport
on
ozone
concentrations
in
the
San
Antonio
region
during
the
1999
episode.
These
runs
required
the
application
of
a
masking
program
to
the
model
to
"
zero
out"
the
anthropogenic
VOC,
NOx,
and
CO
emissions
for
three
urban
Texas
areas:
Austin,
Corpus
Christi,
and
Houston.
Transported
emissions
from
each
of
these
areas
can
impact
ozone
concentrations
in
the
San
Antonio
area.

PAVE
Graphics
After
removing
anthropogenic
emissions
generated
by
Austin,
Corpus
Christi,
and
Houston
from
the
1999
base
case
model,
the
modeling
output
was
processed
through
a
graphics
software
program
(
PAVE)
to
provide
visual
depictions
of
the
resulting
impact
on
regional
ozone
concentrations.
The
following
series
of
figures
compare,
day
by
day
for
September
15­
20,
1999,
the
changes
in
ozone
predicted
by
the
precursor
reductions
in
each
of
these
three
urban
areas.

Different
colors
in
the
plots
distinguish
variations
in
the
amount
of
ozone.
The
red
and
orange
areas
indicate
higher
levels
of
increased
ozone
levels
while
blue
and
green
areas
indicate
levels
of
ozone
reductions
from
the
transport
of
air
mass.
The
predicted
increases
in
ozone
concentrations
(
red
and
yellow
shading)
within
some
areas
of
the
4­
km
subdomain
are
noteworthy.
This
is
particularly
evident
in
the
zero
out
Corpus
Christi
runs,
although
the
zero
out
Austin
runs
for
September
15­
17th
also
depict
relatively
small
areas
of
yellow
shading.

In
general,
according
to
these
graphics,
removing
Houston
anthropogenic
emissions
impacted
ozone
concentrations
in
all
SAER
counties
and
east
Texas.
When
Houston's
emissions
are
removed,
a
blue
plume
usually
appears
which
indicates
an
area
of
maximum
reduced
ozone
levels
stretching
a
considerable
distance
downwind
of
Houston.
Removing
Austin
anthropogenic
emissions
typically
impacted
ozone
concentrations
in
the
northern
SAER
region.
Removing
emissions
from
Corpus
Christi
is
least
likely
to
impact
the
four
SAER
counties.
M­
13
Figure
M­
13.
Results
of
"
zero
out"
model
runs
for
Wednesday,
September
15,
1999.

As
shown,
removing
Austin
and
Houston
anthropogenic
precursor
emissions
reduced
modeled
ozone
concentrations
in
each
SAER
county
(
or
a
portion
of
a
county)
on
September
15th.
However,
removing
Corpus
Christi
anthropogenic
emissions
had
no
projected
impact
on
SAER
ozone
concentrations
on
the
same
day.
The
red
and
orange
areas
near
and
in
the
Corpus
Christi
metropolitan
area
indicate
increased
ozone
levels
due
to
the
reduced
scavenging.
The
blue
and
green
areas
indicate
ozone
reductions
from
the
transport
of
air
mass.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
14
Figure
M­
14.
Results
of
"
zero
out"
model
runs
for
Wednesday,
September
16,
1999.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
15
Figure
M­
15.
Results
of
"
zero
out"
model
runs
for
Wednesday,
September
17,
1999.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
16
Figure
M­
16.
Results
of
"
zero
out"
model
runs
for
Wednesday,
September
18,
1999.

As
noted
earlier,
when
emissions
are
removed
and
a
blue
plume
appears,
the
plume
indicates
an
area
of
reduced
ozone.
Here,
in
Corpus
Christi's
case,
the
plume
stretches
a
considerable
distance
downwind
of
this
area.
The
downwind
plume
is
very
evident
on
September
18,
1999,
with
less
evidence
of
NOx
scavenging
than
on
most
other
days
for
this
region.

The
plot
for
Houston
clearly
shows
the
effect
of
the
reduction
for
two
days,
given
by
the
two
large
distinct
blue
lobes.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
17
Figure
M­
17.
Results
of
"
zero
out"
model
runs
for
Wednesday,
September
19,
1999.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
18
Figure
M­
18.
Results
of
"
zero
out"
model
runs
for
Monday,
September
20,
1999.

Zero
out
Austin
Anthropogenic
Emissions
Zero
out
Corpus
Christi
Anthropogenic
Emissions
Zero
out
Houston
Anthropogenic
Emissions
M­
19
Graphical
Display
of
Data
The
preceding
graphical
representations
of
the
change
in
ozone
due
to
reductions
in
anthropogenic
regional
emissions
are
based
on
photochemical
modeling
output
data.
Predicted
effects
of
these
reductions
at
various
CAMS
in
the
San
Antonio
region
were
analyzed
numerically
as
well.
The
following
graphs
specifically
show
these
impacts
on
the
design
value.
The
calculation
of
design
value,
which
is
an
off­
model
procedure,
was
based
on
instructions
received
from
the
EPA
and
TCEQ.
The
procedure
averages
the
ozone
levels
for
each
day
of
the
episode
run
with
reduces
precursor
levels
and
compares
this
average
with
the
design
value
for
the
episode.
In
this
way,
the
impact
on
the
design
value
of
any
precursor
reduction
scenario
can
be
estimated.
As
figure
M­
19
indicates,
removing
the
Houston/
Galveston
area
anthropogenic
emissions
lowers
the
CAMS
58
design
value
by
about
2.60
parts
per
billion.
This
impact
is
considerably
greater
than
the
impacts
which
are
estimated
by
removing
Austin
and
Corpus
Christi
area
anthropogenic
emissions.
In
figure
M­
20
removing
the
Houston/
Galveston
area
emissions
shows
a
reduction
of
2.72
ppb
at
CAMS
23,
which
is
also
considerably
higher
than
readings
due
to
removing
Austin
and
Corpus
Christi
area
anthropogenic
emissions.
Figures
M­
19
and
M­
20
reflect
averages
over
the
5­
day
modeling
period
of
the
peak
8­
hour
ozone
averages
predicted
by
the
model.

Figure
M­
19.
Design
Value
Reduction
due
to
the
Removal
of
Houston,
Austin,
and
Corpus
Christi
Anthropogenic
Emissions,
CAMS
58,
Sept.
1999
2.61
parts
per
billion
0.57
parts
per
billion
0.40
parts
per
billion
0.0%
0.3%
0.6%
0.9%
1.2%
1.5%
1.8%
2.1%
2.4%
2.7%
3.0%

Percent
Reduction
in
Ozone
Houston
Removed
Corpus
Christi
Removed
Austin
Removed
M­
20
Figure
M­
20.
Design
Value
Reduction
due
to
the
Removal
of
Houston,
Austin,
and
Corpus
Christi
Anthropogenic
Emissions,
CAMS
23,
Sept.
1999
2.72
parts
per
billion
0.64
parts
per
billion
0.27
parts
per
billion
0.0%
0.5%
1.0%
1.5%
2.0%
2.5%
3.0%
3.5%

Percent
Reduction
in
Ozone
Houston
Removed
Corpus
Removed
Austin
Removed
Figure
M­
21.
Design
Value
Reduction
due
to
the
Removal
of
Bexar
County
and
San
Antonio
Region
Anthropogenic
Emissions,
CAMS
23,
Sept.
1999
and
2007
18.76
parts
per
billion
21.44
parts
per
billion
21.41
parts
per
billion
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%

Percent
Reduction
in
Ozone
Bexar
County
Removed
2007
San
Antonio
Removed
(
4­
County
Area)
2007
San
Antonio
Removed
(
4­
County
Area)
1999
M­
21
Further
analysis
of
the
emission
inventory
for
the
Sept.
1999
episode
revealed
that
removal
of
local
(
i.
e.,
Bexar,
Comal,
Guadalupe
and
Wilson
Counties)
anthropogenic
emissions
cause
an
average
reduction
of
about
25%
of
the
peak
ozone
predicted
around
CAMS
23
during
this
episode.
Figure
M­
21
shows
the
results
of
this
additional
analysis.
The
figure
indicates
that
the
proportion
of
emissions
attributed
to
and
originating
in
the
local
San
Antonio
region
is
predicted
to
increase
from
1999
to
2007.
Hence,
the
region's
contribution
to
the
design
value
for
the
Sept.
1999
episode
was
around
24.09%
of
the
total
design
value,
or
21.44
parts
per
billion
of
ozone;
the
estimated
2007
contribution
is
around
25.36%,
or
21.41
ppb.

In
addition,
the
analysis
further
indicates
that,
due
to
the
implementation
of
air
quality
control
strategies
in
the
Houston/
Galveston
area
by
the
year
2007,
the
amount
of
pollution
transport
from
this
area
will
noticeably
decrease.
However,
this
region
still
remains
the
largest
emissions
contributor
to
San
Antonio
as
compared
to
the
other
contributing
regions
in
Texas.
This
can
be
seen
in
Figure
M­
22.
Contributions
from
other
regions
affecting
the
air
quality
in
San
Antonio
region
are
also
shown
for
comparison
purposes.

Figure
M­
22.
Design
Value
Reduction
due
to
the
Removal
of
Emissions
from
Various
Contributing
Areas
at
CAMS
23,
Sept.
2007
0.14
parts
per
billion
0.64
parts
per
billion
0.09
parts
per
billion
0.24
parts
per
billion
2.25
parts
per
billion
0.55
parts
per
billion
0.0%
0.3%
0.6%
0.9%
1.2%
1.5%
1.8%
2.1%
2.4%
2.7%
3.0%

Percent
Reduction
in
Ozone
Houston
Removed
Corpus
Christi
Removed
Austin
Removed
Wilson
County
Removed
Guadalupe
County
Removed
Comal
County
Removed
Comparing
the
results
of
zero
out
runs
for
Austin,
Corpus
Christi,
Houston
and
San
Antonio,
it
is
predicted
that
removing
the
SAER
anthropogenic
emissions
has,
by
far,
the
greatest
impact
on
local
ozone
concentrations.
Therefore,
it
is
clear
the
San
Antonio
region
contributes
to
its
own
air
quality
problem.
The
1999
base
simulation
predicts
that
without
the
SAER
anthropogenic
precursor
emissions,
ozone
concentrations
within
the
San
Antonio
region
would
be
reduced
by
as
much
as
~
24%.
Although
this
provides
an
indication
of
the
significance
of
SAER­
generated
anthropogenic
emissions,
it
also
indicates
that
approximately
three­
quarters
of
the
ground­
level
ozone
in
the
SAER
is
a
M­
22
product
of
natural
and
transported
emission
sources
 
emissions
over
which
the
SAER
has
no
control.

Removing
Houston's
anthropogenic
emissions
had
the
greatest
impact
on
San
Antonio
area
ozone
levels.
Without
the
reductions
credited
to
the
Houston
area
for
2007
(
attributed
to
reductions
achieved
through
the
Houston
SIP),
for
example,
the
San
Antonio
region
would
likely
fail
to
show
attainment
as
it
currently
does.

Tables
M­
1
through
M­
3
provide
the
projected
reduction
in
ozone
concentrations
(
percent
difference
between
Base
Case
F
and
the
sensitivity
run)
within
the
7x7
grids
surrounding
three
San
Antonio
monitors
after
removing
anthropogenic
emissions
for
Austin,
Corpus
Christi,
or
Houston.
For
comparison
purposes,
anthropogenic
VOC,
NOx,
and
CO
emissions
generated
in
the
4­
county
San
Antonio
region
were
also
removed
from
the
model
during
one
of
the
sensitivity
runs.
Results
of
removing
or
zeroing
out
precursor
emissions
are
provided
for
both
the
base
year
and
attainment
year
simulations.

The
highest
predicted
ozone
concentrations,
in
parts
per
billion,
for
each
day
of
the
September
13
 
20
episode
were
averaged
for
the
areas
near
the
three
monitors
listed
in
the
columns
labeled
"
Predicted
Average
O3"
in
the
tables
below.
These
modeled
results
indicate
that,
under
the
meteorological
conditions
experienced
during
the
September
1999
episode,
removing
the
anthropogenic
emissions
from
Houston
had
the
greatest
impact
on
SAER
ozone
concentrations
when
compared
to
other
sources
of
transport.

The
most
significant
reductions
in
predicted
ozone
concentrations
were
associated
with
removing
anthropogenic
precursor
emissions
generated
in
the
4­
county
San
Antonio
region.
While
transport
contributes
to
ground­
level
ozone
buildup
in
Central
Texas,
a
significant
portion
of
the
ozone
problem
is
created
locally.
This
is
particularly
evident
in
figure
M­
21
which
illustrates
the
importance
of
local
precursor
production
on
local
ozone
concentrations.

T
able
M­
1.
CAMS
23
Sensitivity
Run
Year
Design
Value
%
Reduction
Base
Case
F
1999
89.00
­­­
Zero
Austin
1999
88.73
0.31%
Zero
Corpus
Christi
1999
88.36
0.72%
Zero
Houston
1999
86.28
3.06%
Zero
San
Antonio
(
4­
county
area)
1999
1999
67.56
24.09%

Base
Case
F
2007
84.42
­­­
Zero
Austin
2007
84.11
0.29%
Zero
Corpus
Christi
2007
83.81
0.65%
Zero
Houston
2007
82.11
2.67%
Zero
San
Antonio
(
4­
county
area)
2007
2007
63.13
25.35%
M­
23
Table
M­
2.
CAMS
58
Sensitivity
Run
Year
Design
Value
%
Reduction
Base
Case
F
1999
87.00
­­­
Zero
Austin
1999
86.60
0.46%
Zero
Corpus
Christi
1999
86.43
0.66%
Zero
Houston
1999
84.39
3.00%
Zero
San
Antonio
(
4­
county
area)
1999
1999
67.47
22.44%

Base
Case
F
2007
82.04
­­­
Zero
Austin
2007
81.68
0.46%
Zero
Corpus
Christi
2007
86.43
0.66%
Zero
Houston
2007
84.39
3.00%
Zero
San
Antonio
(
4­
county
area)
2007
2007
67.47
22.44%

Table
M­
3.
CAMS
678
Sensitivity
Run
Year
Design
Value
%
Reduction
Base
Case
F
1999
77.00
­­­
Zero
Austin
1999
76.84
0.21
Zero
Corpus
Christi
1999
76.23
1.00
Zero
Houston
1999
73.97
3.93
Zero
San
Antonio
(
4­
county
area)
1999
1999
66.18
14.06
Base
Case
F
2007
74.61
­­­
Zero
Austin
2007
74.27
0.33
Zero
Corpus
Christi
2007
73.97
0.77
Zero
Houston
2007
72.31
2.95
Zero
San
Antonio
(
4­
county
area)
2007
2007
62.51
16.33
Ozone
Source
Apportionment
Technology
(
OSAT)
Analysis
Finally,
the
photochemical
model
can
help
demonstrate
the
relationship
between
sources
of
ozone
precursor
in
the
emissions
inventory,
their
rates
of
precursor
production,
and
the
contribution
these
sources
make
to
the
total
ambient
ozone
contribution
within
a
given
grid
cell
of
the
model.
The
specific
limitations
of
this
Ozone
Source
Apportionment
Technology
(
OSAT)
include:
1.
the
limits
to
regional
source
identification,
which
regions
are
distinguished
by
a
userdesigned
surface
area
restricted
to
modeling
grid
cells
as
surface
area
units;
2.
the
limits
to
categorization
of
precursors,
which
is
by
the
four
major
emission
groups
of
Area/
Non­
Road,
Mobile,
Elevated
Point,
and
Biogenic;
3.
the
limits
to
determination
of
sources
or
areas
beyond
the
grid
in
space
and
time,
which
the
model
sees
as
Boundary
Conditions
and
Initial
Conditions,
respectively,
and;
4.
the
increased
time
required
for
pre­
processing,
the
model
OSAT
runs
themselves,
and
data
post­
processing
and
analysis.
M­
24
Nevertheless,
the
OSAT
tech
does
allow
a
clearer
determination
of
the
sources
of
ambient
ozone
in
the
model.
And,
even
given
the
limits
listed
above,
the
number
of
variables
does
allow
for
an
analysis
containing
extensive
detail
and
variability.
This
additional
tool
is
explained
as
follows.

The
OSAT
module
in
the
CAMx
photochemical
model
allows
for
the
identification
of
sources
in
specific
areas
and
for
the
subsequent
tracking
of
their
impacts
on
different
areas.
This
module
was
used
to
show
the
impact
of
other
regions
on
air
quality
in
San
Antonio
area
for
the
model
run
referred
to
as
"
run18.
sos".
The
Anthropogenic
Precursor
Culpability
Assessment
(
APCA)
option
within
this
module
was
used
to
identify
ozone
formation
attributed
to
the
anthropogenic
NOx
sources
and
less
ozone
formation
attributed
to
biogenic
sources.

The
outputs
from
OSAT
analysis,
presented
in
the
following
pages,
identify
contributors
to
the
peak
levels
of
ozone
recorded
at
CAMS
23,
during
the
1999
episode,
by
source
regions,
by
source
categories
or
emission
groups,
and
by
type
of
precursor
(
e.
g.,
NOx).

As
mentioned,
the
regions
by
which
sources
are
identified
and
distinguished
are
limited
in
number.
The
modeler
designs
them;
the
regions
are
mapped
according
to
the
modeling
grid
domain,
using
grid
cells
as
the
smallest
units
to
build
the
final
rectangular
source
region
or
subdomain.
The
names
of
the
regions
for
this
run
(
Gulf
of
Mexico,
etc.)
are
listed
above.

The
precursors
are
categorized
as
one
of
the
four
major
emission
groups:
Area/
Non­
Road,
Mobile,
Elevated
Point,
or
Biogenic
sources.
The
numbers
in
each
list
above
identify
the
Names
and
Precursor
type
in
the
following
charts.

In
reading
the
charts
and
graphs
on
the
following
pages,
notice
that
the
pie
charts
are
labeled
with
a
one
or
two
digit
number
corresponding
with
the
Source
Area
ID
number
(
or
IC
or
BC
for
Initial
or
Boundary
Conditions).
This
is
followed
by
a
comma,
which
is
followed
by
a
three
digit
number
corresponding
to
the
Source
Category
ID
number.
The
percentage
contribution
accompanies
this
number
pair.

The
tables
accompanying
each
graph
lists,
in
descending
order
by
percentage
contribution,
the
twelve
greatest
contributions
to
ozone
at
the
"
receptor,"
or
grid
cell
in
the
model.
The
grid
cell
chosen
here
contains
the
CAMS
23
monitor,
so
the
"
receptor"
designated
carries
that
name.
Notice
also
that
each
rows
of
the
table
identifies
both
a
Source
Area
and
an
Emissions
Group;
the
same
row
will
have
a
percentage
in
the
far
right
hand
column.
This
percentage
correlates
the
contribution
to
ozone
at
the
receptor
due
to
precursor
production
from
that
area
and
that
source
type.
For
example,
the
September
15,
1999
table
lists
that
Austin's
Mobile
source
NOx
made
up
3.6%
of
the
ozone
and
Austin's
Mobile
source
VOC
contributed
0.1%
of
the
ozone
predicted
by
the
model
at
the
receptor
cell,
i.
e.,
at
CAMS
23.
M­
25
OSAT/
APCA
Regions
Plot
Date:
March
12,
2004

Compilation
Date.
March
3,
2004
NORTH
Source
Regions
used
in
The
CAMx
APCA
Application
Source
Categories
used
in
the
CAMx
APCA
Application
ID
Name
ID
Category
1
Gulf
of
Mexico
001
Biogenic
2
South
Texas
002
Elevated
Point
3
Corpus
Christi
003
Mobile
5
San
Antonio
004
Area/
Non­
Road
6
Victoria
7
Houston
8
Louisiana
9
Other
States
10
Beaumont
11
Austin
12
North
Texas
13
Central
Texas
14
East
Texas
15
Dallas
IC
Initial
Conditions
BC
Boundary
Conditions
M­
26
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
13
To
14
Date
=
9/
15/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
70
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
22.3%
Boundary
Conditions
BC
25.6%
San
Antonio
5
Elevated
Point
002
5.5%
0.0%
5.5%
Other
States
9
Area/
Non­
Road
004
3.3%
0.5%
3.8%
Austin
11
Mobile
003
3.6%
0.1%
3.7%
Louisiana
8
Area/
Non­
Road
004
3.4%
0.1%
3.5%
North
Texas
12
Mobile
003
2.7%
0.1%
2.8%
Austin
11
Area/
Non­
Road
004
2.6%
0.1%
2.7%
Other
States
9
Elevated
Point
002
2.7%
0.0%
2.7%
Houston
7
Elevated
Point
002
2.6%
0.0%
2.7%
Other
States
9
Mobile
003
1.9%
0.2%
2.2%
Central
Texas
13
002
2.1%
0.0%
2.1%
All
Others
20.3%

Total
100%
Source
Area
Emission
Group
0
10
20
30
40
50
60
70
80
Ozone
(
ppb)
NOx
limited
VOC
limited
Boundary
Initial
IC
22%

5,
002
5%
9,
004
4%
11,
003
4%
8,
004
4%
12,
003
3%
11,
004
3%
9,
002
3%
7,
002
3%
9,
003
2%
13,
002
2%
All
Others,
20%

BC
25%
M­
27
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
12
To
13
Date
=
9/
16/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
73
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
1.2%
Boundary
Conditions
BC
47.9%
Other
States
9
Elevated
Point
002
6.7%
0.0%
6.7%
Other
States
9
Area/
Non­
Road
004
4.9%
0.9%
5.8%
Louisiana
8
Area/
Non­
Road
004
4.8%
0.1%
4.9%
Houston
7
Elevated
Point
002
3.8%
0.0%
3.8%
Other
States
9
Mobile
003
3.0%
0.4%
3.4%
San
Antonio
5
Elevated
Point
002
3.2%
0.0%
3.2%
Austin
11
Mobile
003
3.1%
0.0%
3.2%
Austin
11
Area/
Non­
Road
004
2.6%
0.1%
2.6%
Louisiana
8
Elevated
Point
002
2.3%
0.0%
2.3%
Louisiana
8
Mobile
003
1.9%
0.0%
1.9%
All
Others
13.1%

Total
100%
Source
Emission
Area
Group
0
10
20
30
40
50
60
70
80
Ozone
(
ppb)
NOx
lim
ited
VOC
lim
ited
Boundary
Initial
IC
1%

9,
002
7%
9,
004
6%
8,
004
5%
7,
002
4%
9,
003
3%
5,
002
3%
11,
003
3%
11,
004
3%
8,
002
2%
8,
003
2%
All
Others,
13%

BC
48%
M­
28
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
12
to
13
Date
=
9/
17/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
70
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
2.4%
Boundary
Conditions
BC
48.9%
Other
States
9
Elevated
Point
002
5.7%
0.0%
5.8%
Louisiana
8
Area/
Non­
Road
004
5.2%
0.2%
5.4%
Other
States
9
Area/
Non­
Road
004
4.0%
1.3%
5.3%
Other
States
9
Mobile
003
2.9%
0.6%
3.5%
San
Antonio
5
Elevated
Point
002
3.4%
0.0%
3.4%
Louisiana
8
Elevated
Point
002
2.7%
0.0%
2.7%
Austin
11
Mobile
003
2.0%
0.1%
2.1%
Austin
11
Area/
Non­
Road
004
1.9%
0.2%
2.1%
Louisiana
8
Mobile
003
1.8%
0.1%
1.9%
Other
States
9
Biogenics
001
0.8%
0.8%
1.6%
All
Others
14.8%

Total
100%
Source
Emission
Area
Group
0
10
20
30
40
50
60
70
80
Ozone
(
ppb)
NOx
limited
VOC
limited
Boundary
Initial
IC
2%

9,
002
6%
8,
004
5%
9,
004
5%
9,
003
3%
5,
002
3%
8,
002
3%
11,
003
2%
11,
004
2%
8,
003
2%
9,
001
2%
All
Others,
15%

BC
50%
M­
29
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
13
To
14
Date
=
9/
18/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
72
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
1.8%
Boundary
Conditions
BC
44.1%
San
Antonio
5
Elevated
Point
002
6.9%
0.0%
7.0%
Other
States
9
Area/
Non­
Road
004
3.7%
0.9%
4.7%
Other
States
9
Elevated
Point
002
3.3%
0.0%
3.3%
Other
States
9
Mobile
003
2.9%
0.4%
3.3%
Houston
7
Elevated
Point
002
3.0%
0.1%
3.1%
Houston
7
Area/
Non­
Road
004
1.7%
0.7%
2.4%
Houston
7
Mobile
003
2.0%
0.3%
2.4%
North
Texas
12
Mobile
003
1.9%
0.2%
2.1%
Austin
11
Area/
Non­
Road
004
1.6%
0.1%
1.7%
Louisiana
8
Area/
Non­
Road
004
1.5%
0.1%
1.7%
All
Others
22.4%

Total
100%
Source
Emission
Area
Group
0
10
20
30
40
50
60
70
80
Ozone
(
ppb)
NOx
limited
VOC
limited
Boundary
Initial
IC
2%

5,
002
7%
9,
004
5%
9,
002
3%
9,
003
3%
7,
002
3%
7,
004
2%
7,
003
2%
12,
003
2%
11,
004
2%
8,
004
2%
All
Others,
22%

BC
45%
M­
30
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
13
To
14
Date
=
9/
19/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
84
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
0.7%
Boundary
Conditions
BC
42.4%
Houston
7
Elevated
Point
002
7.0%
0.2%
7.2%
San
Antonio
5
Elevated
Point
002
5.7%
0.1%
5.8%
Houston
7
Area/
Non­
Road
004
3.2%
1.1%
4.2%
Other
States
9
Area/
Non­
Road
004
2.8%
0.8%
3.6%
Louisiana
8
Area/
Non­
Road
004
2.8%
0.3%
3.0%
Houston
7
Mobile
003
2.5%
0.3%
2.8%
Other
States
9
Elevated
Point
002
2.6%
0.0%
2.7%
Victoria
6
Area/
Non­
Road
004
1.8%
0.6%
2.4%
Other
States
9
Mobile
003
1.8%
0.3%
2.1%
San
Antonio
5
Area/
Non­
Road
004
1.3%
0.6%
1.9%
All
Others
21.1%

Total
100%
Source
Emission
Area
Group
0
10
20
30
40
50
60
70
80
90
Ozone
(
ppb)
NOx
limited
VOC
limited
Boundary
Initial
IC
1%

7,
002
7%
5,
002
6%
7,
004
4%
9,
004
4%
8,
004
3%
7,
003
3%
9,
002
3%
6,
004
2%
9,
003
2%
5,
004
2%
All
Others,
21%

BC
42%
M­
31
Contributions
By
Type
Contributions
By
Source
Area
Receptor
=
San
Antonio
CAMS
23
Time
=
14
To
15
Date
=
9/
20/
1999
Scenario
=
CAMx
v3.10
run18.
sos.
apca
Sep
13­
20
1999
Total
Ozone
=
87
ppb
Detailed
Ozone
Apportionment
Percent
Ozone
from
NOx
VOC
Total
Initial
Conditions
IC
0.3%
Boundary
Conditions
BC
43.4%
San
Antonio
5
Elevated
Point
002
7.9%
0.1%
8.1%
San
Antonio
4,
5
Mobile
003
4.6%
2.5%
7.1%
Victoria
6
Area/
Non­
Road
004
1.8%
3.2%
5.1%
North
Texas
12
Mobile
003
3.1%
1.7%
4.7%
San
Antonio
4,
5
Area/
Non­
Road
004
1.5%
2.2%
3.7%
North
Texas
12
Area/
Non­
Road
004
1.3%
1.6%
2.9%
Other
States
9
Area/
Non­
Road
004
1.7%
0.7%
2.4%
Houston
7
Elevated
Point
002
2.2%
0.1%
2.3%
Houston
7
Area/
Non­
Road
004
1.1%
0.6%
1.7%
Other
States
9
Elevated
Point
002
1.6%
0.0%
1.6%
All
Others
16.6%
Total
100%
Source
Emission
Area
Group
0
10
20
30
40
50
60
70
80
90
100
Ozone
(
ppb)
NOx
limited
VOC
limited
Boundary
Initial
IC
0%

5,
002
8%
6,
004
5%
12,
003
5%
4,
003
4%
5,
003
3%
12,
004
3%
9,
004
2%
7,
002
2%
4,
004
2%
5,
004
2%
All
Others,
20%

BC
44%
M­
32
Note
that
the
contributions
due
to
the
Initial
Conditions
drop
quickly
from
22%
to
approximately
zero
percent
by
the
end
of
the
run.
This
is
anticipated,
given
the
nature
and
definition
of
Initial
Conditions.
The
Boundary
Conditions
quickly
assume
a
greater
importance
than
the
25%
contribution
on
the
first
modeling
day,
September
15,
1999.

Note
that
the
greatest
contribution
by
total
percentage
from
San
Antonio
sources
listed
for
any
one
day
is
19%,
on
September
20.
All
San
Antonio
anthropogenic
sources
appear
as
contributors
listed
in
the
top
twelve
only
on
September
20.
Also,
Elevated
Point
sources
from
San
Antonio
are
consistently
among
the
top
twelve
sources
for
every
day
of
the
episode.
The
hourly
time
periods
for
each
daily
analysis
were
chosen
for
their
high
hourly
ozone
values.

Both
the
consistent
importance
of
the
Boundary
Conditions
as
a
contribution
source,
as
well
as
the
low
value
of
contribution
from
the
San
Antonio
anthropogenic
emissions
(
never
greater
than
20%)
in
this
run
analysis,
tend
to
correlate
with
the
other
evidence
supporting
transport
as
an
important
component
of
readings
in
the
local
area.

To
further
prove
this
point,
a
ribbon
graph
was
produced
again
by
employing
OSAT
module
to
depict
hourly
ozone
concentrations,
contributed
by
San
Antonio's
neighboring
areas,
during
the
Sept.
1999
episode
in
parts
per
billion
(
ppb).
For
generating
this
graph,
the
CAMS
23
was
specified
in
the
coordinate
of
the
CAMx
grid
as
a
"
Point"
format
for
the
receptor
definition.
Concentrations
at
the
point
are
determined
by
bi­
linear
interpolation
of
the
surrounding
four
coarse
grid
surface
cells
as
described
in
the
ENVIRON
CAMx
User
Guide
version
3.00
pages
5­
17.

In
the
following
graph,
which
looks
like
a
saw
edge
due
to
the
diurnal
variation
of
ozone
during
the
episode,
the
colored
strips
identify
the
amount
of
ozone
generated
from
each
source
category
included
in
the
study
area.
The
San
Antonio
source
category
(
magenta),
for
the
exception
of
eighth
day,
appears
to
have
contributed
a
small
portion
of
the
total
ozone
concentrations
during
this
episode.

The
first
three
strips
at
the
bottom
of
the
graph
represent
the
impacts
of
initial
condition
(
light
blue),
boundary
condition
(
yellow),
and
biogenic
sources.
As
the
graph
reveals,
contributions
from
sources
such
as
other
state
(
dark
blue)
and
Houston
(
red)
at
times
exceed
18
ppb.

Maximum
contribution
levels
for
selected
areas
during
various
days
of
the
episode
are:
Other
States
source
category
18.24
ppb
on
the
fourth
day.
Houston/
Beaumont
and
Port
Arthur
source
category
19.22
ppb
on
the
fourth
day.
San
Antonio
source
category
16.78
ppb
on
the
eighth
day.
M­
33
CAMx
OSAT
Analysis,
1999
CAMS
23
0
10
20
30
40
50
60
70
80
90
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
0:

00
8:

00
16:

00
Sept.
13­
20,
1999,
Hour
Ozone
Concentration
(

ppb)
Initial
Conditions
Boundary
Conditions
Biogenics
Sources
Houston/
BPA
Sources
Victoria/
Corpus
Sources
Other
Texas
Counties
Sources
Other
States
Sources
Austin
Sources
San
Antonio
Sources
M­
34
Conclusion
The
effects
of
transport
on
local
ozone
levels
have
been
verified
across
parts
of
the
United
States,
notably
during
the
May
1998
smoke
episode
and
the
September
2002
haze
event.
The
May
1998
smoke
episode
verification
caused
EPA
to
exclude
certain
days
of
ozone
data
from
compliance
calculations
in
nine
states
due
to
these
May
1998
fires.
Historically,
as
air
arrives
in
San
Antonio
during
a
day
of
local
high
ozone
levels,
the
air
typically
flows
from
the
east
across
a
variety
of
point
sources
throughout
the
state
of
Texas.

An
analysis
of
the
1999
photochemical
model
has
been
used
also
to
demonstrate
evidence
of
transport.
It
is
important
to
keep
in
mind
that
the
results
from
the
model
analysis
do
pertain
to
a
single
episode,
and
so
illustrate
a
result
specific
to
that
particular
episode.
On
the
other
hand,
the
September
13­
20,
1999
period
was
chosen
specifically
because
the
wind
patterns
were
typical
of
ozone
episodes
for
the
region,
as
documented
in
Appendix
A.
Reducing
anthropogenic
emissions
from
selected
Texas
cities
in
the
1999
photochemical
model
also
shows
the
influence
of
transport
from
individual
sources.

Finally,
the
local
2007
design
value
of
84.35
ppb
is
lowered
only
21.97
ppb
by
removing
all
anthropogenic
emissions
in
the
four­
county
Early
Action
Compact
region
of
San
Antonio.
This
indicates
that
the
maximum
ozone
reductions
possible
through
enactment
of
local
strategies
in
the
San
Antonio
EAC
region
is
limited;
any
locally
enacted
strategies
must
in
fact
fall
short
of
this
reduction
level.
Moreover,
this
limited
depth
of
ozone
reductions
through
local
actions
indicates
the
degree
to
which
successful
air
quality
efforts
can
best
be
achieved
through
state
and
federal
efforts
coupled
with
local
actions.
Success
of
the
San
Antonio
Clean
Air
Plan
relies
upon
the
support
of
our
local
planning
effort
by
the
Texas
Commission
on
Environmental
Quality
and
the
US
Environmental
Protection
Agency.
However,
it
also
strongly
relies
on
the
success
of
TCEQ
and
EPA
to
fully
enact
both
the
State
Implementation
Plan
revisions
currently
proposed
by
the
state
of
Texas,
notably
for
Houston,
but
on
continued
support
for
and
enactment
of
further
state
and
federal
air
quality
rules.
M­
35
Addendum:
the
State
of
Texas
The
State
of
Texas
is
also
very
active
in
consideration
of
transport
issues.

The
Sonoma
Technology
study
(
MacDonald
et
al.,
1999)
was
supported
by
TCEQ
and
reported
that,
on
average,
40%
of
San
Antonio's
peak
ozone
was
locally
generated.
Furthermore,
the
study
concluded
that
background
ozone
was
around
70
ppb,
with
local
sources
adding
approximately
45
ppb.
Sonoma
analysts
also
studied
the
impact
of
transport
from
two
high­
ozone
aircraft
flight
days
where
long­
range
trajectories
were
available.
They
surmised
that
high
ozone
episodes
were
associated
with
local
stagnation
and/
or
recirculation
during
night
and
morning
hours.
During
one
case
(
August
28,
1998
flight),
it
was
determined
that
material
was
transported
from
the
south
with
background
ozone
at
69
ppb.
During
the
second
case
(
October
9,
1998
flight),
material
was
transported
from
the
northeast
with
background
ozone
at
78
ppb.

Other
actions
by
the
State
are
equally
proactive.
R.
B.
"
Ralph"
Marquez,
TCEQ
Commissioner,
spoke
before
the
US
House
of
Representatives'
Subcommittee
on
Energy
and
Air
Quality
on
July
22,
2003.
He
gave
the
subcommittee
two
examples
of
transport
as
he
recognized
them.
From
his
remarks:
The
first
example
is
one
of
interstate
transport
which
demonstrates
a
September
2002
haze
episode
in
which
haze
formed
in
the
Midwestern
U.
S.
and
moved
across
the
eastern
U.
S.
and
into
the
southern
states
and
Texas
over
several
days.
Our
analysis
of
satellite
imagery
and
monitor
readings
of
ozone
and
particulate
matter
shows
the
impact
of
pollutant
transport
on
Texas
communities
during
the
September
episode.
For
example,
8­
hour
ozone
values
in
Houston
climbed
from
41
ppb
on
September
9
to144
ppb
on
September
13,
2002.
On
those
same
days,
particulate
matter
climbed
from
7
micrograms/
cubic
meter
to
56
micrograms/
cubic
meter.
Similar
increases
for
these
pollutants
occurred
in
other
major
metropolitan
areas,
Dallas­
Fort
Worth,
San
Antonio,
and
Beaumont­
Port
Arthur.
The
second
case
is
an
example
of
intrastate
transport
on
a
day
(
September
1,
2000)
when
the
Beaumont­
Port
Arthur
(
BPA)
area
exceeds
the
one­
hour
ozone
standard
at
least
partially
due
to
transport
from
the
Houston
area.
In
fact,
when
we
reviewed
all
of
the
1­
hour
ozone
exceedances
between
1998
and
2002,
we
found
that
approximately
one­
half
of
the
exceedances
occurred
on
days
when
there
was
a
contribution
from
Houston.
In
addition,
the
highest
monitored
readings
in
BPA
occurred
on
days
when
there
was
a
contribution
from
Houston.
`
Bump
Up'
(
2003)

The
Air
Improvement
Resources
(
AIR)
Committee
continues
to
support
these
findings
and
the
dedication
to
find
solutions
to
transport
issues.
On
March
3,
2004,
the
AIR
Executive
and
Advisory
Committees
approved
the
following
text,
which
was
subsequently
sent
in
a
letter
to
TCEQ
Chairman
Kathleen
Hartnett
White:
Dear
Chairman
White,
As
you
are
certainly
aware,
transport
of
ozone
and
ozone
precursors
into
the
San
Antonio
region
can
be
a
significant
component
of
our
area's
high
ozone
and
high
PM2.5
levels.
The
effects
of
smoke
from
Mexico
on
our
local
air
pollution
in
1998
were
well
documented
by
the
US
Environmental
Protection
Agency.
Former
TCEQ
Chairman
Huston
reported
to
us
that
evidence
of
haze
as
distant
as
the
Ohio
River
Valley
has
coincided
with
widespread
high
pollution
and
visibility
reductions
here
in
mid­
September
2002.
In
a
letter
to
AIR
Committee
Chairman
Jay
Millikin
dated
April
4,
2003,
Chairman
Huston
wrote,
"
In
every
ozone
exceedance
recorded
to
date
in
the
San
Antonio
area,
we
have
measured
high
background
levels
coming
into
the
area."
While
he
also
cautioned
that
"
each
urban
area
of
the
state,
including
San
M­
36
Antonio,
contributes
significantly
to
its
own
pollution,"
this
fact
in
and
of
itself
does
not
diminish
the
effect
of
transport.
The
Air
Improvement
Resources
Committee
requests
the
Texas
Commission
on
Environmental
Quality
to
develop
an
action
plan
to
deal
with
transport
issues.
We
hope
that
action
by
the
state
of
Texas,
in
coordination
and
collaboration
with
other
states
in
this
country
and
with
our
neighbors
in
Mexico,
as
well
as
any
other
sources
of
pollution
that
come
to
us
from
beyond
our
borders,
can
help
us
meet
our
air
pollution
challenge
effectively.
We
remain
committed
to
improving
local
air
quality
through
our
Early
Action
Compact,
other
local
endeavors
undertaken
by
local
citizens
and
agencies,
and
our
continuing
cooperation
with
the
state
provided
by
legislated
aid.

The
letter
was
signed
by
Chairman
Jay
Millikin,
who
is
also
a
Commissioner
of
Comal
County,
Texas,
and
Vice
Chairman
Nelson
Wolff,
who
is
also
County
Judge
of
Bexar
County,
Texas.

References
MacDonald,
Clinton
P.,
Blumenthal,
Donald
L.,
Roberts,
Paul
T.,
and
Crews,
Jesse
M.
(
November
30,
1999).
Analysis
of
Air
Quality
Data
Collected
by
the
Baylor
University
Aircraft
(
presentation).
Petaluma,
CA:
Sonoma
Technology,
Inc.
Available
online
as
ftp://
ftp.
crwr.
utexas.
edu/
pub/
Baylor_
aq/
PRES.
pdf
The
Naval
Research
Laboratory's
NAAPS,
Navy
Aerosol
Analysis
and
Prediction
system.
Accessed
on
April
2,
2003.
Available
on­
line:
http://
www.
nrlmry.
navy.
mil/
aerosol/
globaer/
ops_
01/
noramer/
200205/
2002050918_
globa
er_
ops_
noramer.
gif
EPA's
John
S.
Seitz
before
the
US
Senate
Subcommittee
On
Clean
Air,
Wetlands,
Private
Property
And
Nuclear
Safety,
November
13,
2000:
http://
www.
senate.
gov/~
epw/
107th/
sei_
1113.
htm
Texas
Commission
on
Environmental
Quality
(
TCEQ),
April
2003.
"
Air
Pollution
Events."
Available
on­
line:
http://
www.
tnrcc.
state.
tx.
us/
updated/
air/
monops/
airpollevents/
2002/
event2002­
09­
12sat.
html.

Texas
Commission
on
Environmental
Quality
(
TCEQ),
April
2003.
"
Air
Pollution
Events­
San
Antonio
High
Ozone
September
12,
2002."
Available
on­
line:
http://
www.
tnrcc.
state.
tx.
us/
updated/
air/
monops/
airpollevents/
2002/
event2002­
09­
12sat.
html.

Environmental
Protection
Agency
(
EPA),
March
2003.
"
AIRNow."
Available
on­
line:
http://
www.
epa.
gov/
airnow/
ozone.
html.

Texas
Commission
on
Environmental
Quality
(
TCEQ).
Technical
Analysis
Division,
"
Continental
Transport
of
Air
Pollution
into
Texas:
Sep.
11­
14,
2002,"
PowerPoint
presentation
made
during
the
March
7,
2003
meeting
of
the
Dallas­
Fort
Worth
Photochemical
Modeling
Technical
Committee.
Available
online:
http://
www.
tnrcc.
state.
tx.
us/
air/
aqp/
sipmod/
dfwaq_
techcom.
html.
Presentation:
M­
37
ftp://
ftp.
tnrcc.
state.
tx.
us/
pub/
OEPAA/
TAD/
Modeling/
DFWAQSE/
Sci_
Tech_
Committees/
P
MTC/
20030307/
Regional_
Haze_
2002Sep­
BrianFoster.
pdf
`
Bump­
Up'
Policy
Under
Title
I
of
the
Clean
Air
Act:
Hearings
before
Subcommittee
on
Energy
and
Air
Quality,
of
the
House
Committee
of
Energy
and
Commerce,
108th
*
Cong.,
1d
Sess.
(
2003)
(
testimony
of
TCEQ
Commissioner
R.
B.
"
Ralph"
Marquez).
Testimony
available
online:
http://
energycommerce.
house.
gov/
108/
Hearings/
07222003hearing1025/
Marquez1615.
ht
m