EPA-910/9-82-090
c/EFW
United States
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
November 1982
Recommendations on a
SHORTZ/LONGZ S02
Air Quality
Model Methodology
for the
Tacoma Tidef lots
Area
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EPA-910/9-82-090
November 1982
RECOMMENDATIONS OK A SHORTZ/LONGZ SO AIR
QUALITY MODEL METHODOLOGY FOR THE
TACOMA TIDEFLATS AREA
Prepared by
J. F. Bowers, VI. R. Hargraves and A. J. Anderson
EPA Contract No. 68-02-2547
Task Order No. 4
Modification No. 4
Project Officer
Robert B. Wilson
U. S. Environmental Protection Agency, Region 10
1200 Sixth Avenue
Seattle, Washington 98101
H. E. Cramer company, inc.
UNIVERSITY OF UTAH RESEARCH PARK
POST OFFICE BOX 8049
SALT LAKE CITY, UTAH 84108
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This document has not been peer and administratively reviewed
within EPA and does not necessarily reflect the policies or views or tne
U. S. Environmental Protection Agency.
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TABLE OF CONTENTS
Section
Title
Page
INTRODUCTION
1.1 Background and Purpose
1.2 Description of the Site
1.3 Ambient Air Quality Standards and Class II
PSD Increments Applicable to the Tideflats
Sources
1.4 Report Organization
SHORTZ/LONGZ EMISSIONS INVENTORY FOR THE EXISTING
AND PROPOSED SO SOURCES
REVIEW OF THE AVAILABLE METEOROLOGICAL AND SO AIR
QUALITY DATA
3.1 Review of the Available Meteorological Data
3.2 Review of the Available SO Air Quality Data
3.3 Examination of Selected Short-Term Periods
21
21
47
65
STATISTICAL EVALUATION OF PREVIOUS APPLICATIONS OF
SHORTZ AND LONGZ IX THE TACOMA AREA 99
PRELIMINARY SHORTZ/LONGZ DISPERSION MODEL METHODOLOGY 111
5.1 SHORTZ Dispersion Model Methodology 111
5.2 LONGZ Dispersion Model Methodology 126
5.3 Assessment of the Preliminary SHORTZ/LONGZ Dis-
persion Model Methodology 128
SUGGESTIONS FOR FUTURE WORK 133
REFERENCES 141
Appendix
A
B
C
MATHEMATICAL MODELS USED TO CALCULATE GROUND-LEVEL
CONCENTRATIONS A-l
RECEPTOR INPUTS FOR THE TACOMA TIDEFLATS AREA B-l
PRELIMINARY SHORTZ AND LONGZ METEOROLOGICAL INPUTS C-l
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SECTION 1
INTRODUCTION
1.1 BACKGROUND AND PURPOSE
The industrialized Tacoma, Washington tideflats area is one of
the most pressing and challenging air quality modeling problems facing the
U. S. Environmental Protection Agency (EPA) Region 10, the Washington State
Department of Ecology (DOE) and the Puget Sound Air Pollution Control Agency
(PSAPCA). The problem is pressing because the air quality impacts of a
proposed new source and a proposed plant modification must be evaluated for
compliance with the Prevention of Significant Deterioration (PSD)
Regulations and the National, Washington State and Puget Sound Ambient Air
Quality Standards. The problem is challenging because of the complexity of
the topography and meteorology of the tideflats area and the wide variety
of emissions characteristics for the sources located in the area. The only
previous dispersion model analysis of the area that included a detailed
model verification effort (Cramer, et al., 1976) considered all of the
existing sources of sulfur dioxide (SO ) emissions, but focused attention
on the most significant SO source—the ASARCO-Tacoma copper smelter.
Based on the performance in the 1976 study of the SHORTZ/LONGZ dispersion
models, EPA Region 10 considers the SHORTZ/LONGZ models to be the most
appropriate of the generally available dispersion models for application to
the Tacoma tideflats area. Modification No. 4 of Task No. 4 of EPA
Contract No. 68-02-2547 directed the H. E. Cramer Company. Inc. to use the
funds and time available under the contract in a continuation of the 1976
study with the focus on the tideflats sources.
The primary purpose of the study described in this report was to
develop a SHORTZ/LONGZ dispersion model methodology for application to the
existing and proposed SO- sources in the Tacoma tideflats area. The three
major subtasks of the study were defined as follows:
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1. Review the available air quality and meteorological
data from the Tacoma area, analyze these data to
determine the various meteorological conditions which
lead to high measured ambient SO concentrations and
analyze the meteorological data to determine other
possible meteorological conditions which may lead to
high SO levels.
2. Evaluate the performance of the SHORTZ/LONGZ computer
models for periods determined in Subtask 1, using the
August 1981 draft EPA report "Interim Procedures for
Evaluation of Air Quality Models" as a guideline.
3. Prepare a report which details a modeling methodology
using the SHORTZ/LONGZ air quality dispersion models.
The purpose of the methodology is to estimate maximum
SO impacts in the industrial area of Tacoma,
Washington. The document shall specify a procedure for
use of the models which includes model inputs (sources,
receptors, meteorology), model options, and an example
of model output. The document shall also include the
justification for the recommended procedure and results
of the model performance evaluation. It is important
that the worst-case meteorological conditions recom-
mended by the contractor are adequate to estimate
maximum SO impacts for averaging periods of 24 hours,
3 hours, one hour, and 5 minutes. An averaging period
of one year may also be of concern.
Because of the time and level-of-effort constraints for the completion of
the work under Modification No. 4 to Task Order No. 4 of EPA Contract No.
68-02-2547, it was not possible fully to complete all of Subtasks 2 and 3.
However, recommendations for future work to accomplish these objectives are
presented in this report, and an interim SHORTZ/LONGZ model methodology is
suggested.
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1.2 DESCRIPTION OF THE SITE
Figure 1-1 is a topographic map of the Tacoma tideflats and ad-
jacent areas. The tideflats comprise the area of flat terrain in the
Puyallup River valley bounded on the west by the elevated terrain of the
Tacoma peninsula, on the northwest by Commencement Bay, and on the north
and east by the elevated terrain of Brown's Point. Terrain elevations
above mean sea level range from about 3 meters in the tideflats to over 180
meters on Brown's Point and to over 120 meters on the Tacoma peninsula.
The combination of elevated terrain surrounding the tideflats and the
presence of the land-water interface tends to produce complex mesoscale
meteorological circulations. Thus, the development of an appropriate
dispersion model methodology for the existing and proposed S07 sources in
the tideflats area is a challenging task.
The ASARCO copper smelter, which is located near the tip of the
Tacoma peninsula, is the principal source of SO emissions in the region.
The location of the 172-meter ASARCO Main Stack is shown by the ® symbol
in Figure 1-1. The ASARCO smelter currently uses a Meteorological
Curtailment Program (MCP) to maintain the applicable ambient air quality
standards for SO , which are discussed below in Section 1.3. (The MCP
curtails S0? emissions whenever meteorological conditions conducive to the
occurrence of high short-term ground-level concentrations occur or are
anticipated.) Based on the results of our previous study of the ASARCO
smelter (Cramer, et^ _al_. , 1976) as well as the results of this study, the
ASARCO smelter is primarily responsible for the SO,, ambient air quality on
the Tacoma peninsula. ASARCO emissions also affect S09 ambient air quality
on Brown's Point and occasionally affect ambient air quality within the
tideflats.
The existing SO,, sources located within the tideflats are the St.
Regis kraft mill, the U. S. Oil & Refining plant, the Kaiser aluminum
plant, the Pennwalt plant and the Hooker Chemicals (Hooker Division of
Occidental Chemical Corporation) plant. (Figure 1-1 does not show all of
the buildings at the Kaiser plant because the most recent USGS map available
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T A C 0 M A
Figure 1-1. Topographic map of the Tacoma tideflats and adjacent areas. Elevations are in feet
above mean sea level and the contour interval is 100 feet (30.5 meters). The ©
symbol shows the location of the ASARCO Main Stack.
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for the area was updated in 1961.) The SO emissions from the existing SC>2
sources in the tideflats are discharged from stacks which range in height
from 12 meters (U. S. Oil & Refining flare stacks) to 81 meters (St. Regis
Recovery Boiler No. 3). Additionally, SO,, is contained in the slightly
buoyant roof monitor emissions from the potlines at the Kaiser plant.
Tacoma City Light proposes to build a cogeneration plant with a single
108-meter stack and it is our understanding that Kaiser is considering the
use of an existing, but currently unused, 152-meter stack. Thus, the stack
heights of potential concern for the sources within the tideflats range
from 12 to 152 meters. These variations in emission heights and source
types further complicate the development of an appropriate dispersion model
methodology for the tideflats area.
1.3 AMBIENT AIR QUALITY STANDARDS AND CLASS II PSD INCREMENTS
APPLICABLE TO THE TIDEFLATS SOURCES
The combined emissions from the existing and proposed SO sources
located in and adjacent to the Tacoma tideflats area must comply with the
National Ambient Air Quality Standards (NAAQS), the Washington State ambient
air quality standards and the Puget Sound ambient air quality standards.
Additionally, the combined emissions from sources subject to the Prevention
of Significant Deterioration (PSD) Regulations (for example, the Tacoma
City Light cogeneration plant) must comply with the Class II PSD
Increments. Table 1-1 gives the National, Washington State and Puget Sound
SO- ambient air quality standards as well as the SO Class II PSD
Increments. All of the ambient air quality standards and PSD Increments in
Table 1-1 are given in units of parts per million (ppm) because these are
the units used to define the Washington State and Puget Sound air quality
standards. The NAAQS for SO are defined in units of either ppm or
micrograms per cubic meter, while the PSD Increments for SO are defined in
units of micrograms per cubic meter. One ppm of SO is equal to 2,620
micrograms per cubic meter. For example, the 3-hour, 24-hour and annual
Class II PSD Increments of 0.195, 0.035 and 0.008 ppm are respectively
equal to 512, 91 and 20 micrograms per cubic meter.
5
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TABLE 1-1
AMBIENT AIR QUALITY STANDARDS AND CLASS II PSD INCREMENTS
FOR SO APPLICABLE TO THE TIDEFLATS SOURCES
Time
Period
5 minutes
1 hour
1 hour
3 hours
24 hours
30 days
Annual
National Standards (ppm)
Primary
—
—
—
—
0.143
—
0.03b
Secondary
—
—
—
0.50a
—
—
—
Washington
State Standards
(ppm)
—
0.403
0.25°
—
o.ioa
—
0.02b
Puget Sound
Standards
(ppm)
i.ood
0.40b
0.25°
—
o.iob
0.04b
0.02b
Class II PSD
Increment
(ppm)
—
—
—
0.1953
0.0353
—
0.008b
Not to be exceeded at any given point more than once per year.
Never to be exeeded.
Not to be exceeded at any given point more than two times in any 7 consecutive
days.
Not to be exceeded at any given point more than once in any 8 consecutive hours.
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Inspection of the footnotes at the bottom of Table 1-1 shows that
the National, Washington State and Puget Sound annual ambient air quality
standards may never be exceeded. Also, the Puget Sound 30-day and 24-hour
ambient air quality standards and one of the two Puget Sound 1-hour standards
may never be exceeded. The remaining ambient air quality standards may be
exceeded at any given point (receptor) one or more times per year, depending
on the standard. For example, a short-term NAAQS or PSD Increment is violated
at a given point during the second short-term period in a year with a short-
term concentration above the corresponding NAAQS or PSD Increment. In
general, the same definition of a violation of a short-term NAAQS or PSD
Increment is applied to the results of dispersion model calculations. That
is, the second-highest short-term concentration calculated for a receptor
during a year normally is used to assess the compliance of the receptor
with the corresponding NAAQS or PSD Increment. However, as noted in the
current Guideline on Air Quality Models (EPA, 1978), air pollution control
agencies may specify that the highest rather than the highest of the second-
highest short-term concentrations calculated for all receptors be used to
evaluate compliance with the short-term NAAQS and PSD Increments if there
are uncertainties about the representativeness of the data available for
input to the dispersion model. We recommend that the dispersion model
methodology for the Tacoma tideflats area use the highest rather than the
highest of the second-highest calculated short-term concentrations to assess
compliance with all of the short-term ambient air quality standards and PSD
Increments listed in Table 1-1 for two reasons. First, the most restrictive
short-term air quality standards are the Puget Sound standards which may
never be exceeded. Second, there are uncertainties about the applicability
of the available meteorological data under all meteorological conditions
because of the complexity of the terrain in the tideflats area. Our recommen-
dation does not apply to the Puget Sound 5-minute standard of 1 ppm (not to
be exceeded at any given point more than once in any 8 consecutive hours)
nor to the Puget Sound and Washington State 1-hour standards of 0.25 ppm
(not to be exceeded at any given point more than two times in any 7
consecutive days). These two standards are virtually impossible to address
with any of the currently available dispersion modeling techniques. For
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consistency with the Puget Sound ambient air quality standards, we
recommend that maximum running mean 3-hour and 24-hour average
concentrations be used to assess compliance with the 3-hour and 24-hour
ambient air quality standards and PSD Increments.
1.4 REPORT ORGANIZATION
In addition to the Introduction, this report contains five major
sections and three appendices. Section 2 gives the SHORTZ/LONGZ S02 emissions
inventory for the existing and proposed sources in the Tacoma tideflats
area. Section 3 summarizes our analysis of the available meteorological
and air quality data and also includes a discussion of several model calcula-
tions which were made to evaluate possible modeling approaches. In Section
4, statistical procedures suggested in the August 1981 draft EPA report
"Interim Procedures for Evaluation of Air Quality Models" are applied to
the results of the SHORTZ/LONGZ concentration calculations for the Tacoma
area that are given in Appendix E of the report by Cramer; et_ al. (1976).
Section 5 outlines a preliminary SHORTZ/LONGZ dispersion model methodology
for the tideflats area and Section 6 contains suggestions for future work
to refine this methodology. The mathematical equations implemented by the
SHORTZ/LONGZ computer codes are discussed in Appendix A. More detailed
documentation and user's instructions for the SHORTZ/LONGZ models are con-
tained in the report by Bjorklund and Bowers (1982). Appendix B lists the
receptor inputs suggested for the tideflats and adjacent areas. Hourly
SHORTZ inputs for selected "worst-case" short-term periods and an annual
wind summary for input to LONGZ are listed in Appendix C.
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SECTION 2
SHORTZ/LONGZ EMISSIONS INVENTORY FOR THE EXISTING
AND PROPOSED SO SOURCES
The SO. emissions inventory for the major existing and proposed
sources in and adjacent to the Tacoma, Washington tideflats area was de-
veloped from information provided by:
• The Puget Sound Air Pollution Control Agency (PSAPCA,
1982)
• The U. S. Environmental Protection Agency, Region 10
(Wilson, 1982a and 1982c)
• Kaiser Aluminum & Chemical Corporation (Schmeil, 1982)
Additionally, a layout of the ASARCO smelter, acquired by the H. E. Cramer
Company during a previous study of the smelter (Cramer, et^ al., 1976), was
used to develop source inputs for fugitive emissions from the ASARCO smelter.
Table 2-1 identifies by source number the existing and proposed
SO sources located in and adjacent to the tideflats. The source parameters
in the format required for input to the SHORTZ/LONGZ dispersion models are
listed in Table 2-2. Source Type 0 is a stack source and Source Type 1 is
a building source. The SHORTZ/LONGZ building source option is applied to
the fugitive emissions from the ASARCO smelter and to the roof monitor
emissions from the Kaiser aluminum plant. It is important to note that the
stack radius should be entered as zero in the SHORTZ/LONGZ calculations for
each stack with a radius enclosed by parentheses in Table 2-2. A zero
stack radius deletes the Cramer, et_ a^. (1975) stack-tip downwash correction
in SHORTZ/LONGZ calculations. Based on the stack's Froude number and our
previous experience (See Appendix G of Bjorklund and Bowers, 1982), we do
not believe that the Cramer, et^ al_. stack-tip downwash correction is appli-
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TABLE 2-1
IDENTIFICATION BY SOURCE NUMBER OF EXISTING AND PROPOSED SO SOURCES
IN AND ADJACENT TO THE TACOMA TIDEFLATS AREA
Source No.
101
102
201
202
203
204
205
206
301 & 302
303 - 308
309 - 316
317 - 320
321 - 324
325
326
401
402
403
501
502
503
504
505
601
701
Source Name
ASARCO Main Stack
ASARCO Fugitive Emissions
St. Regis Boiler No. 1
St. Regis Boilers No. 3 - No. 5
St. Regis Boiler No. 6
St. Regis Lime Kiln No. 1
St. Regis Recovery Boiler No. 3
St. Regis Recovery Boiler No. 4
Kaiser Potlines 1 and 2
Kaiser Potline 4
Kaiser Potline 5
Kaiser Lines 1 and 2 Dry Scrubber Stacks
Kaiser Line 4 Dry Scrubber Stacks
Kaiser Bake Oven Stack
Kaiser Line 5 Dry Scrubber Stack
Pennwalt Boiler/Pots
Pennwalt B & W Boiler
Pennwalt G & S Boiler
U. S. Oil & Refining Flare Stacks
U. S. Oil & Refining Power Boilers 1-3
U. S. Oil & Refining Heater H-3
U. S. Oil & Refining Heater H-8
U. S. Oil & Refining H-ll, 801 & 901
Occidental Chemical Corp. Hooker
Division Boilers
Tacoma City Light Cogneration Plant
Existing
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Proposed
X
X
X
X
10
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TABLE 2-2
SHORTZ/LONGZ SOURCE INPUT PARAMETERS FOR THE EXISTING AND PROPOSED S02 SOURCES
IN THE TACOMA TIDEFLATS AREA
Source
No.
101
102
201
202
203
204
205
206
301
302
303
304
305
306
307
308
309
310
311
312
313
314
Type
0
1
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Of)
2
Emission
Rate
(g/sec)
2540.00
62.00
6.00
1.00
27.00
1.00
5.00
10.00
2.10
2.10
0.48
0.48
0.48
0.48
0.48
0.48
0.26
0.26
0.26
0.26
0.26
0.26
UTM X
(m)
537,350
537,400
543,450
543,450
543,450
543,500
543,400
543,400
547,875
547,875
547,715
547,715
547,715
547,715
547,715
547,715
547,525
547,525
547,525
547,525
547,525
547,525
UTM Y
(m)
5,238,080
5,238,400
5,234,700
5,234,700
5,234,700
5,234,650
5,234,750
5,234,750
5,234,054
5,233,947
5,234,210
5,234,150
5,234,090
5,234,030
5,233,970
5,233,910
5,234,330
5,234,270
5,234,210
5,234,150
5,234,090
5,234,030
Stack Height (m)
for Type 0
or Effective
Emission Height
(m) for Type 1
172
30
25
41
30
30
81
77
15.2
15.2
15.2
15.2
15.2
15.2
15.2
15.2
16.8
16.8
16.8
16.8
16.8
16.8
Stack or
Building
Base
Elevation
(m MSL)
43
9
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Exit Temperature
(°K) for Type 0
or Length of
Short Side (m)
for Type 1
366
38
419
333
447
348
341
460
91
91
60
60
60
60
60
60
60
60
60
60
60
60
Exit Volume
(m /sec) for
Type 0 or Length
of Long Side (m)
for Type 1
376.7
30.0
16.3
64.8
39.6
17.5
48.2
161.2
107
107
60
60
60
60
60
60
60
60
60
60
60
60
Stack Radius (m)
for Type 0* or
Angle (deg) to
Long Side for
Type 1
(3.65)
135
0.70
1.15
1.00
0.70
1.45
2.15
0
0
0
0
0
0
0
0
0
0
0
0
0
0
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TABLE 2-2 (Continued)
Source
No.
315
316
317
318
319
320
321
322
323
324
325
326
401
402
403
501
502
503
504
505
Type
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
so2
Emission
Rate
(g/sec)
0.26
0.26
6.60
5.28
6.60
5.28
7.20
7.20
5.76
5.76
1.56
51.54
9.00
9.00
9.00
2.00
3.00
1.00
1.00
5.00
UTM X
On)
547,525
547,525
548,325
548,615
548,325
548,615
547,574
547,595
547,574
547,595
547,458
547,608
547,350
547,350
547,350
545,700
545,900
545,700
545,700
545,700
UTM Y
On)
5,233,970
5,233,910
5,234,175
5,234,175
5,234,152
5,234,152
5,233,958
5,233,958
5,233,931
5,233,931
5,234,116
5,233,990
5,234,950
5,234,950
5,234,950
5,233,500
5,233,500
5,233,500
5,233,500
5,233,500
Stack Height (m)
for Type 0
or Effective
Emission Height
(m) for Type 1
16.8
16.8
15.8
15.8
15.8
15.8
15.8
15.8
15.8
15.8
15.2
152.4
46
18
18
12
49
43
24
29
Stack or
Building
Base
Elevation
(m MSL)
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Exit Temperature
(°K) for Type 0
or Length of
Short Side (m)
for Type 1
60
60
344
344
344
344
344
344
344
344
388
344
450
533
533
811
627
711
783
672
Exit Volume
(m /sec) for
Type 0 or Length
of Long Side (m)
for Type 1
60
60
69.7
69.7
69.7
69.7
68.2
68.2
68.2
68.2
34.0
234.0
3.5
12.3
11.3
0.14
16.40
23.10
3.50
6.40
Stack Radius (m)
for Type 0* or
Angle (deg) to
Long Side for
Type 1
0
0
1.74
1.74
1.74
1.74
1.74
1.74
1.74
1.74
0.71
(3.96)
(1.05)
0.60
(0.75)
(0.10)
0.75
0.70
(0.45)
0.45
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TABLE 2 (Continued)
Source
No.
601
701
Type
0
0
so2
Emission
Rate
(g/sec)
12.00
46.20
UTM X
(m)
545,200
545,900
UTM Y
(m)
5,236,200
5,235,900
Stack Height (m)
for Type 0
or Effective
Emission Height
(m) for Type 1
58
108
Stack or
Building
Base
Elevation
(m MSL)
3
3
Exit Temperature
(°K) for Type 0
or Length of
Short Side (m)
for Type 1
427
413
Exit Volume
(m /sec) for
Type 0 or Length
of Long Side (m)
for Type 1
14.9
194.0
Stack Radius (m)
for Type 0* or
Angle (deg) to
Long Side for
Type 1
(1.35)
2.1
A stack radius enclosed by parentheses should be entered as zero to delete the Cramer, et al. (1975) stack-tip
downwash correction which is not applicable because of the stack's Froude number (see Appendix G of Bjorklund
and Bowers, 1982).
u>
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cable to a stack if the radius is enclosed by parentheses in Table 2-2.
The possible exception is the ASARCO Main Stack. On the basis of
comparisons of calculated and observed SO. concentrations, we previously
concluded that the stack-tip downwash correction should not be applied to
the ASARCO Main Stack (see Appendix D of Cramer, et_ al. 1976). However,
subsequent changes in the stack's Froude number increase the possibility
that stack-tip downwash may occur. For the purpose of dispersion model
calculations in the tideflats area, the applicability of the stack-tip
downwash correction to the ASARCO Main Stack is unlikely to be a critical
issue. Consequently, our current emissions inventory assumes no stack-tip
downwash for the ASARCO plume.
We point out that the majority of the source inputs listed in
Table 2-2 for the existing sources were specified by PSAPCA (1982) for use
in dispersion model calculations to evaluate the Prevention of Significant
Deterioration (PSD) Permit Application for the proposed Tacoma City Light
cogeneration plant. The inputs in several cases combine multiple stacks
with identical or very similar emissions characteristics into a single
model stack. All source inputs for the ASARCO fugitive emissions except
the horizontal dimensions of the ASARCO reverberatory furnace building were
provided by PSAPCA (1982). We estimated these dimensions from the ASARCO
blueprint cited above. The source inputs for the proposed Tacoma City
Light plant were provided by EPA Region 10 (Wilson, 1982a). We developed
the Kaiser source inputs from information provided by Wilson (1982a) and a
Kaiser plant layout (Drawing 753-45-6-5), which was provided to EPA Region
10 by Kaiser (Schmeil, 1982). The development of the Kaiser source inputs
is discussed in the following paragraphs.
The existing Kaiser plant consists of Potlines 1 and 2 and Potline
4. Separate dry scrubber (baghouse) systems serve Potlines 1 and 2 (in
combination) and Potline 4. Kaiser currently plans to add a new Potline 5
and a new Carbon Bake Oven. Emissions from the dry scrubber system for the
new Potline 5 may be discharged from an existing, but currently unused,
152-meter stack. Although the exact locations and emissions parameters for
14
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the proposed new Kaiser sources were not known during the course of our
study, we have used the information available for these sources to develop
source inputs to serve as a guide in the development of future SHORTZ/LONGZ
source inputs.
The Kaiser potline emissions are horizontally discharged from
building roof monitors at a temperature approximately 14 degrees Celsius
above the ambient air temperature. These low-level emissions are rapidly
distributed by the cavity circulation of the aerodynamic wake of the potroom
complex and quickly assume the dimensions of the complex. The SHORTZ/LONGZ
building source option currently cannot address the buoyant rise of the
roof monitor emissions. Because the roof monitor emissions account for
only 12 percent of the total SO emissions from the existing Kaiser plant,
our current emissions inventory uses the SHORTZ/LONGZ building source
option to model the potline emissions with the effective emission height
defined as the actual emission height. The Potroom 1 and 2 complex is
represented in Table 2-2 by two building sources, the Potroom 4 complex is
represented by six building sources and the Potroom 5 complex is
represented by eight building sources. As explained in Section 2.3.2 in
the report by Bjorklund and Bowers (1982), multiple subsources with
approximately equivalent lengths and widths are used to maintain
computational accuracy.
It is important to recognize that the neglect of the buoyant rise
of the emissions from roof monitors at the Kaiser plant will tend to over-
estimate the impact of these emissions within about the first kilometer
downwind, especially under light wind conditions. If the impact of these
emissions becomes of critical concern, the building source option of the
SHORTZ/LONGZ models could be modified to use simplified forms of the line
source plume rise equations utilized by the Aluminum Association's Buoyant
Line and Point Source (BLP) Dispersion Model (Schulman and Scire, 1980).
For winds normal to the potlines, the final rise of the roof monitor emissions
15
-------
under adiabatic or unstable conditions is given by the solution to the
following equation:
Ah
3 . 3L
NL TT
6hbL 3
y, NL TT
3 F x
-
2ir u{h}
3 2
(2-1)
F' = g L W w f 1 -
(2-2)
'\5/8 F' 4,
49 ; f,55m4/sec
,\2/5 ,
— ; — > 55
4, 3
(2-3)
where
Ah
NL
L =
\ =
u{h} =
g =
W =
w =
the line source plume rise under adiabatic or unstable
conditions (m)
the length of the roof monitor (m)
the height of the potline buildings (m)
the adiabatic entrainment coefficient -0.6 (Briggs, 1972)
the mean wind speed at the roof monitor emission height (m/sec)
2
the acceleration due to gravity (m/sec )
the width of the roof monitor (m)
the effective exit velocity of the roof monitor emissions
(m/sec)
the exit temperature of the roof monitor emissions (°K)
the ambient air temperature (°K)
16
-------
For winds normal to the potlines, the final rise of the roof
monitor emissions under stable conditions Ah is given by the solution
O Li
an equation which is identical to Equation (2-1) except that the stable
entrainment coefficient y ~ 0.66 (Briggs, 1972) is substituted for y £
the term at the far right of Equation (2-1) is replaced by
(2-4)
S = T^ S <2'5>
a
where 86/3z is the vertical potential temperature gradient in degrees
Kelvin per ineter. If a stable potential temperature gradient is entered,,
the plume rise used in the model calculations should be the minimum of the
rises given by the adiabatic and stable rise equations. We suggest that
the buoyancy flux F1 for each potroom complex be set equal to the sum of
the fluxes for the two roof monitors. The plume rise calculated for each
potroom complex should be assigned to each subsource used to represent the
complex.
The dry scrubber stacks for Kaiser Potlines 1 and 2 are grouped
in two parallel rows of stack clusters with an east-to-west row orientation.
Each individual stack cluster contains four stacks in a north-to-south
line. The dry scrubber stacks for Potline 4 have the same configuration
except that the parallel rows of stack clusters are rotated 90 degrees and
thus have a north-to-south orientation. Four stacks per cluster, nine
clusters per row and two rows per dry scrubber system yield 72 individual
stacks per dry scrubber system. To preserve the horizontal geometry of
these dry scrubber stacks, we assigned two model stacks per row of stack
clusters. The location of each model stack is at the centroid of the four
17
-------
or five stack clusters which it represents, while the SO emission rate is
equal to the combined emission rate for the four or five stack clusters.
Because of the close proximity of the stacks, some enhancement in buoyant
plume rise can be expected as the result of the merging of individual stack
plumes. To account for this enhancement in plume rise, we assigned to the
model stacks effective volumetric emission rates which are based on a semi-
empirical approach developed by Briggs (1974).
Briggs (1974) gives the enhancement in buoyant plume rise for a
row of n stacks as
E =
Ah
n+S]
i+sj
1/3
(2-6)
S = 6
(n-l)s
3/2
(2-7)
where Ah is the plume rise for the merged plume, Ah is the plume rise for
an individual (isolated) plume and s is the center-to-center stack spacing.
Briggs (1974, p. 27) notes that, "While the empirical enhancement was de-
veloped using line source data, it is suggested that it could be conserva-
tively applied to clusters of sources by replacing (n-l)s with the maximum
diameter of the cluster." We assumed that the "maximum diameter" for each
dry scrubber system is the length of a row of parallel stack clusters.
Also, we assumed that Ah typically is on the order of the stack height h.
The Briggs (1971, 1972) plume rise equations used by SHORTZ/LONGZ assume
that the buoyant plume rise is proportional to the cube root of the
volumetric emission rate. It follows that the effective volumetric
emission rate V ff for use in the model plume rise calculations may be
obtained by solving the expression
18
-------
where V is the volumetric emission rate for a single stack. Under the
above assumptions, the enhancement factor E is 2.60.
In addition to the use of an effective volumetric emission rate
for each of the model dry scrubber stacks, an effective stack radius is
assigned to each dry scrubber stack in Table 2-2 in order to maintain the
actual stack exit velocity for use in the stack-tip downwash calculations.
We believe that the Cramer, et_ ai_. (1975) stack-tip downwash correction
probably is adequate to account for the effects on buoyant plume rise of
the aerodynamic wakes of the plant buildings (see Section 3.4 of Bowers and
Anderson, 1981). However, with moderate or strong winds there is likely to
be an enhancement in the initial rate of dispersion of the emissions from
the dry scrubber stacks that is not accounted for in the model
calculations. The effects of this enhancement on the accuracy of the
ground-level concentrations calculated by SHORTZ or LONGZ at distances more
than about 200 meters from the dry scrubber stacks probably are minimal.
19
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20
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SECTION 3
REVIEW OF THE AVAILABLE METEOROLOGICAL AND S0r
AIR QUALITY DATA
3.1 REVIEW OF THE AVAILABLE METEOROLOGICAL DATA
Figure 3-1 shows the locations of the PSAPCA and ASARCO wind
measurement sites in and adjacent to the Tacoma tideflats area. These
locations may be summarized as follows:
• The ASARCO Meeker Junior High School site is on the
high terrain north of the tideflats (Brown's Point
area)
• The ASARCO Ruston and Reservoir sites are northwest of
the tideflats on the elevated terrain of the Tacoma
peninsula
• Although not shown in Figure 3-1, the ASARCO Benny's
(N26th & Pearl) site and the PSAPCA N26th & Pearl site
are about 660 meters south-southwest of the ASARCO
Reservoir site
• The PSAPCA Federal Way site is on high terrain
northeast of the tideflats (see the upper right-hand
corner of Figure 3-1)
• The PSAPCA Fire Station No. 12 site is near the center
of the tideflats
• The PSAPCA Willard School site is on the rising terrain
at the southwestern edge of the tideflats
21
-------
'MEEKER to. HISH SCHOOL SITE 1 i
Figure 3-1.
Topographic map of the Tacoma tideflats area showing the locations of the existing
and proposed S02 sources and the wind and/or SO2 air quality monitoring sites. Elevations
are in feet at>ove mean sea level, <9nd the contour interval is 1OO feet (3O. 5 meters)
-------
PSAPCA (Knechtel, 1982) provided the H. E. Cramer Company with a
computer tape containing the 1981 hourly wind data from all PSAPCA sites in
and adjacent to the Tacoma tideflats area and ASARCO (Watson, 1982) provided
EPA Region 10 with a computer tape containing the 1981 30-minute average
wind data from the Benny's and Meeker sites. We used our Meteorological
and Air Quality Statistical Analysis Program (MAQSAP) to analyze the wind
data from the PSAPCA Fire Station No. 12, Willard School and N26th & Pearl
sites and the ASARCO Benny's and Meeker sites. Table 3-1 give the locations
and elevations of these sites. The following time-of-day categories were
considered in the MAQSAP analyses:
• Morning - Sunrise plus 1 hour to sunrise plus 5 hours
• Afternoon - Sunrise plus 5 hours to sunset minus 1 hour
• Evening - Sunset minus 1 hour to sunset plus 2 hours
• Night - Sunset plus 2 hours to sunrise plus 1 hour
Highlights of the MAQSAP analyses of the wind data are discussed below.
Average Wind Directions and Speeds
Table 3-2 lists, by season and time-of-day category, the average
wind directions and wind speeds at the PSAPCA Fire Station NO. 12, Willard
School and N26th & Pearl sites and the ASARCO Benny's (N26th & Pearl) and
Meeker sites. With the exception of the Meeker site, the annual average
wind speeds at the various sites differ by 0.2 meters per second or less in
spite of the fact that the elevations above mean sea level of the wind
sensors vary by as much as 112 meters. The Meeker site, which is on
elevated terrain near the tip of Brown's Point, is not as sheltered by
overland fetch as are the two N26th & Pearl sites or by surrounding terrain
as are the Fire Station No. 12 and Willard School sites. Thus, the average
wind speeds at the Meeker site are consistently higher than at the other
23
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TABLE 3-1
UNIVERSAL TRANSVERSE MERCATOR (UTM) COORDINATES AND ELEVATIONS
ABOVE MEAN SEA LEVEL (MSL) OF THE WIND MEASUREMENT SITES
Site
Fire Station No. 12
Willard School
N26th & Pearl
Benny's (N26th & Pearl)
Meeker Jr. High School
Operator
PSAPCA
PSAPCA
PSAPCA
ASARCO
ASARCO
QTM X (km)
544.83
524.81
536.68
536.65
543.60
UTM Y (km)
5,234.75
5,230.87
5,235.15
5,235.12
5,238.75
Ground
Elevation
(m MSL)
3
87
123
122
104
Wind Measurement
Height
(m AGL)
16.8
11.3
9.1
5.5
4.6
24
-------
TABLE 3-2
1981 AVERAGE WIND DIRECTIONS AND WIND SPEEDS BY SEASON
AND TIME-OF-DAY CATEGORIES
Time
of
Day
Average Wind Direction (deg) /Average Wind Speed (m/sec)
Winter
Spring
Summer
Fall
Annual
(a) PSAPCA Fire Station No. 12
Night
Morning
Afternoon
Evening
Average
155/1.6
174/1.8
273/2.3
192/2.0
166/1.8
169/1.7
199/2.0
275/3.4
251/2.7
222/2.5
228/1.4
233/1.6
295/3.1
287/2.4
276/2.3
151/1.6
174/1.9
294/2.8
218/2.1
170/2.0
165/1.6
195/1.8
287/3.0
264/2.3
218/2.1
(b) PSAPCA Willard School
Night
Morning
Afternoon
Evening
Average
200/1.6
203/1.6
281/2.2
221/2.1
207/1.8
202/1.9
208/2.0
258/3.0
232/2.5
223/2.4
219/1.4
220/1.4
294/2.6
267/2.0
255/2.0
(c) PSAPCA N26th & Pearl
Night
Morning
Afternoon
Evening
Average
153/1.8
190/1.9
268/2.3
097/2.0
168/1.9
194/2.0
216/2.2
251/2.9
233/2.3
224/2.4
119/1.6
227/1.8
268/2.6
270/2.0
252/2.1
194/1.6
204/1.8
280/2.6
219/2,1
213/1.9
204/1.6
210/1.7
278/2.6
244/2.2
229/2.0
166/1.8
196/2.1
263/2.1
148/2.0
187/2.1
190/1.8
214/2.0
261/2.6
245/2.1
226/2.1
(d) ASARCO Benny's (N26th & Pearl)
Night
Morning
Afternoon
Evening
Average
153/1.7
204/1.9
287/2.2
122/2.0
168/1.9
200/2.3
224/2.7
256/3.3
237/2.7
229/2.8
235/1.9
231/2.1
270/2.9
272/2.3
255/2.4
168/1.7
192/2.0
262/2.4
141/2.0
190/2.0
192/1.9
220/2.2
265/2.9
244/2.2
229/2.3
25
-------
TABLE 3-2 (Continued)
Time
of
Day
Average Wind Direction (deg) /Average Wind Speed (ra/sec)
Winter
Spring
Summer
Fall
Annual
(d) ASARCO Meeker Junior High School
Night
Morning
Afternoon
Evening
Average
114/3.1
170/3.1
235/3.5
091/3.4
121/3.2
149/2.9
198/2.9
258/3.6
227/3.4
201/3.2
190/2.2
211/2.2
284/3.3
310/2.9
259/2.7
123/3.0
177/3.1
277/3.7
092/3.5
133/3.3
132/2.9
192/2.8
272/3.5
079/3.3
174/3.1
26
-------
sites. It is important to note that PSAPCA computes vector mean wind di-
rections and speeds, whereas ASARCO computes scalar mean wind directions
and speeds. If the same instantaneous wind observations are used to calcu-
late vector and scalar mean wind speeds, the vector mean wind speeds should
be less than or equal to the scalar mean wind speeds. We believe that the
differences in the techniques used by PSAPCA and ASARCO to calculate mean
wind directions and speeds probably account for the fact that the ASARCO
Benny's average wind speeds at 5.5 meters above ground level generally are
slightly higher than the PSAPCA N26th & Pearl average wind speeds at a
height of 9.1 meters above ground level. In our previous dispersion model
study of the Tacoma area (Cramer, £^3^., 1976), we assumed that the wind
speed at the PSAPCA N26th & Pearl site was representative of the wind speed
at all elevations below the height above mean sea level of the wind sensor.
Table 3-2 indicates that, at least on the average, this is a reasonable
assumption for the tideflats sources.
The differences in the average wind directions listed in Table
3-2 in part reflect localized effects and are more significant for dispersion
modeling purposes than are the differences in average wind speeds. For
example, the south-southeast winds found on winter nights at Fire Station
No. 12 and the two N26th & Pearl sites appear to be channeled by adjacent
terrain into south-southwest winds at Willard School and east-southeast
winds at the Meeker site. On the average, there is a close correspondence
between the average wind directions at the two N26th & Pearl sites. The
differences in average wind directions given in Table 3-2 for the two N26th
& Pearl sites probably are primarily attributable to the different techniques
used by PSAPCA and ASARCO to compute mean wind directions and speeds.
Wind-Direction Distributions
Figure 3-2 shows the Fire Station No. 12 annual wind-direction
distributions for the night, morning, afternoon and evening time-of-day
categories. The directions in Figure 3-2 are directions from which the
wind is blowing. Comparison of Figures 3-1 and 3-2 shows that the elevated
27
-------
PSAPCA FIRE STATION No. 12
NIGHT
MORNING
AFTERNOON
EVENING
NW NNW
NNE
NE
WNW
ENE
wsw
Figure 3-2. PSAPCA Fire Station No. 12 1981 annual wind-direction
distributions for the night, morning, afternoon and evening
time-of-day categories. Directions are directions from
which the wind is blowing, and the percentage frequency
scale is shown at the right center of the figure.
28
-------
terrain on either side of the tideflats results in a highly channeled
northwest-to-southeast flow. The predominance of offshore (southeast)
winds during the night and, to a lesser extent, during the morning strongly
suggests that these are low-level drainage winds. Because onshore
(northwest) winds are most frequent during the afternoon and, to a lesser
extent, during the evening, there is some evidence for a low-level
sea-breeze type of circulation. Thus, the Fire Station No. 12 wind
directions may not be representative of transport wind directions for
emissions from many of the tideflats sources.
Figure 3-3 shows the Willard School annual wind-direction distri-
butions for the four time-of-day categories. At first glance, there is
very little correspondence between the wind-direction distributions at
Willard School and Fire Station No. 12. As shown by a comparison of Figures
3-1 and 3-3, the winds at Willard School closely parallel the elevated
terrain west of the site. In general, the winds at Willard School are
either from the north or the south-southwest. Although the elevation above
mean sea level of the Willard School wind sensor is near the typical plume
stabilization height for the plumes from many of the sources in the tideflats
area, the Willard School wind directions are unlikely to be representative
of transport wind directions because of the localized terrain channeling of
the winds.
Figure 3-4 shows the PSAPCA N26th & Pearl annual wind-direction
distributions for the four time-of-day categories. The diurnal variations
in the wind-direction distribution at N26th & Pearl are much less pronounced
than at Willard School and Fire Station No. 12. For each time-of-day category,
the N26th & Pearl wind-direction distribution has an approximate north-northeast
to south-southwest or southwest orientation. If allowance is made for the
localized terrain channeling at Willard School, the annual wind-direction
distributions at N26th & Pearl and Willard School are consistent.
29
-------
PSAPCA WILLARD SCHOOL
NIGHT
MORNING
-AFTERNOON
-EVENING
NW
NNW
N
NNE
NE
WNW
W
WSW
ENE
-10-
•15-
-20 25
-30-
\
ESE
sw
ssw
SSE
SE
Figure 3-3. PSAPCA Willard School 1981 annual wind-direction
distributions for the night, morning, afternoon and evening
time-of-day categories. Directions are directions from
which the wind is blowing, and the percentage frequency
scale is shown at the right center of the figure.
30
-------
PSAPCA N26th & PEARL
NIGHT
MORNING
AFTERNOON
•EVENING
NW
NNW
N
NNE
NE
WNW
W
WSW
ENE
-10-
•15-
-20-
-25 30- I
ESE
SW
SSW
SSE
SE
Figure 3-4. PSAPCA N26th & Pearl 1981 annual wind-direction distributions
for the night, morning, afternoon and evening time-of-day
categories. Directions are directions from which the wind
is blowing, and the percentage frequency scale is shown at the
right center of the figure.
31
-------
Figure 3-5 shows the ASARCO Benny's (N26th & Pearl) annual wind-
direction distributions for the four time-of-day categories. Inspection of
Figures 3-4 and 3-5 shows that the annual wind-direction distributions for
the two N26th & Pearl sites are very similar for each time-of-day category.
To facilitate comparisons of the wind-direction distributions at the two
sites, Figure 3-6 shows the PSAPCA and ASARCO N26th & Pearl annual wind-
direction distributions for all time-of-day categories combined. The PSAPCA
winds differ from the ASARCO winds in that the PSAPCA winds show a slightly
higher frequency of winds from the north-northeast and a slightly lower
frequency of winds from the northeast. With these exceptions, the differ-
ences in the two wind-direction distributions are negligible. An important
feature of Figure 3-6 is the almost complete absence of winds from the east
through east-southeast. Assuming the N26th & Pearl wind directions to be
representative of transport wind directions for emissions from the
tideflats sources as well as for emissions from the ASARCO smelter, Figure
3-6 shows that emissions from the tideflats sources are likely to have a
Figure 3-7 shows the annual wind-direction distributions at Meeker
Junior High School for the four time-of-day categories. The night and
morning Meeker wind-direction distributions are similar to a combination of
the night and morning wind-direction distributions at Fire Station No. 12
and N26th & Pearl. The Meeker afternoon and evening wind-direction distri-
butions are similar to the N26th & Pearl afternoon and evening wind-direction
distributions except that the winds toward the north-northwest which occur
at Meeker during the evening do not occur at N26th & Pearl. Winds toward
the north-northwest at the Meeker site are consistent with channeling by
the elevated terrain east of the site.
Some localized effects on winds such as nighttime draining winds
are associated with light wind speeds. It is therefore of interest to
examine the annual wind-direction distributions for all wind speeds and for
moderate or strong wind speeds. The annual wind-direction distributions at
32
-------
ASARCO N26th a PEARL
—NIGHT
MORNING
AFTERNOON
EVENING
NW
NNW
N
NNE
NE
WNW
W
WSW
ENE
-10-
•15-
-20-
•25 30-
ESE
SW
SSW
SSE
SE
Figure 3-5. ASARCO Benny's (N26th & Pearl) 1,981 annual wind-direction
distributions for the night, morning, afternoon and evening
time-of-day categories. Directions are directions from
which the wind is blowing, and the percentage frequency
scale is shown at the right center of the figure.
33
-------
N26th a PEARL
ASARCO
PSAPCA
WNW
WSW
Figure 3-6. ASARCO and PSAPCA N26th & Pearl sites 1981 annual
wind-direction distributions. Directions are directions
from which the wind is blowing, and the percentage
frequency scale is shown at the right center of the figure.
34
-------
ASARCO MEEKER
NIGHT
MORNING
AFTERNOON
EVENING
NW NNW
WNW
WSW
10 15 20 25 30H
ENE
ESE
Figure 3-7.
ASARCO Meeker 1981 annual wind-direction distributions for
the night, morning, afternoon and evening time-of-day
categories. Directions are directions from which the wind
is blowing, and the percentage frequency scale is shown at
the right center of the figure.
35
-------
the three PSAPCA sites for all wind speeds and for wind speeds above 3.1
meters per second are shown in Figures 3-8 and 3-9. respectively.
Similarly, the annual wind-direction distributions at the two ASARCO sites
for all wind speeds and for wind speeds above 3.1 meters per second are
shown in Figures 3-10 and 3-11, respectively. Although the annual wind-
direction distributions for all wind speeds differ significantly from site
to site, the annual wind-direction distributions for wind speeds above 3.1
meters per second are similar if allowance is made for terrain channeling
at Willard School and Meeker.
In summary, our review of the annual wind-direction distributions
from the PSAPCA Fire Station No. 12, Willard School and N26th & Pearl sites
and the ASARCO Benny's (N26th & Pearl) and Meeker sites indicates that the
N26th & Pearl wind directions are the only wind directions unaffected by
localized influences. The Willard School and Meeker wind directions are
influenced by terrain channeling and thus may not be representative of
transport wind directions for emissions from the tideflats sources. During
hours of moderate or strong winds, the Fire Station No. 12 wind directions
are similar to the N26th & Pearl wind directions. However, during hours
with light winds, the Fire Station No. 12 wind directions reflect a channeled
nighttime offshore flow and daytime onshore flow that probably does not
extend to the plume stabilization heights for many of the plumes from the
tideflats sources. If wind data from a single site are to be used in disper-
sion model calculations for all of the existing and proposed SO sources in
the tideflats area, we conclude that winds from one of the two N26th &
Pearl sites are most likely to be representative of transport winds.
Wind Persistence
Our previous study of the air quality impact of SO emissions
from the ASARCO smelter (Cramer, _et_ jrl. , 1976) identified the "critical
wind-speed condition" (persistent raoderate-to-strong winds in combination
with neutral stability) as one of the meteorological conditions conducive
36
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PSAPCA SITES (All Wind Speeds)
FIRE STATION No. 12
WILLARD SCHOOL
N26th ft PEARL
NW NNW
N
NNE
NE
WNW
W
WSW
ENE
•10-
-15-
-20 25-
-30-
ESE
SW
SSW
SSE
SE
Figure 3-8. PSAPCA Fire Station No. 12, Willard School and N26th & Pearl
1981 annual wind-direction distributions for all wind
speeds. Directions are directions from which the wind is
blowing, and the percentage frequency scale is shown at the
right center of the figure.
37
-------
PSAPCA SITES (Wind Speeds Above 3.1 m/sec)
FIRE STATION No. 12
WILLARD SCHOOL
N26th 8 PEARL
NW NNW N
NNE
NE
WNW
W
ENE
//r
-10-
-15-
-20 25-
-30-
wsw
ESE
SW
SSW
SSE
SE
Figure 3-9. PSAPCA Fire Station No. 12, Willard School and N26th & Pearl
1981 annual wind-direction distributions for wind speeds
above 3.1 meters per second. Directions are directions
from which the wind is blowing, and the percentage
frequency scale is shown at the right center of the figure
38
-------
ASARCO SITES (All Wind Speeds)
: BENNY'S
MEEKER
NW NNW
N
NNE
NE
WNW
W
WSW
ENE
-10-
-15-
-20 25-
-30-
ESE
SW
SSW
SSE
SE
Figure 3-10.
ASARCO Benny's (N26th & Pearl) and Meeker 1981 annual
wind-direction distributions for all wind speeds.
Directions are directions from which the wind is blowing,
and the percentage frequency scale is shown at the right
center of the figure.
39
-------
ASARCO SITES (Wind Speeds Above 3.1 m/sec)
BENNY'S
MEEKER
NW NNW N
NNE
NE
WNW
W
WSW
ENE
-10-
•15-
-20 25 30-H
ESt
SW
SSW
S
SSE
SE
Figure 3-11,
ASARCO Benny's (N26th & Pearl) and Meeker 1981 annual
wind-direction distributions for wind speeds above 3.1
meters per second. Directions are directions from which
the wind is blowing, and the percentage frequency scale is
shown at the right center of the figure.
-------
to the occurrence of relatively high 24-hour average ground-level concentra-
tions attributable to buoyant stack emissions. Although it is often diffi-
cult to measure the maximum ground-level concentrations caused by the
critical wind-speed condition because the areas within which the relatively
high concentrations occur have narrow angular dimensions (as measured from
the stack), the importance of this meteorological regime follows from simple
theoretical considerations (Pasquill, 1974 and others) and is supported by
SO- air quality data (Cramer, et^ aJ., 1975; Gorr and Dunlap, 1977; Bowers,
et_ al., 1980; and others). Consequently, our MAQSAP analyses of the PSAPCA
wind data included a search for persistent moderate-to-strong winds.
Table 3-3 lists, for each of the three PSAPCA and two ASARCO wind
measurement sites considered in the MAQSAP analyses, the number of cases
during 1981 when winds above 3.1 meters per second persisted within one of
the sixteen standard 22.5-degree wind-direction sectors for 10 or more
hours. We point out that Table 3-3 underestimates actual wind persistence
within a narrow angular sector because the table does not consider cases
with mean wind directions near the boundary between two standard wind-
direction sectors. However, Table 3-3 provides a relative indication of
the most persistent wind directions. As shown by the table, moderate-to-
strong winds that persist within a narrow angular sector are most common at
Willard School and Meeker Junior High School, the two sites where localized
terrain channeling is most evident. The wind-direction sector with the
largest number of persistent moderate-to-strong wind events is south-
southwest or southwest at each site. Thus, the wind data from all of the
sites indicate that an important meteorological regime for buoyant emissions
from the stacks of the tideflats sources is the critical wind-speed condition
with south-southwest or southwest winds. Because emissions from the proposed
Kaiser and Tacoma City Light tall stacks will not mix to the surface before
they reach the bluff area with south-southwest or southwest winds, relatively
high 24-hour average concentrations attributable to emissions from these
stacks can be expected on the bluff during periods with persistent
moderate-to-strong south-southwest or southwest winds.
41
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TABLE 3-3
NUMBER OF OCCURRENCES DURING 1981 OF WIND SPEEDS ABOVE 3.1
METERS PER SECOND PERSISTING WITHIN ANY STANDARD
22.5-DEGREE SECTOR FOR 10 OR MORE HOURS
Season
Number of Occurrences
N
NNE
E
SSE
s
ssw
sw
WSW
Total
(a) PSAPCA Fire Station No. 12
Winter
Spring
Summer
Fall
Annual
0
0
0
0
0
1
0
0
0
1
0
1
0
0
1
0
0
0
0
0
1
0
0
0
1
1
1
0
1
3
0
1
0
0
1
0
2
0
0
2
3
5
0
1
9
(b) PSAPCA Willard School
Winter
Spring
Summer
Fall
Annual
0
5
2
1
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
1
7
6
1
1
15
0
1
0
0
1
0
0
0
0
0
8
12
3
2
25
(c) PSAPCA N26th & Pearl
Winter
Spring
Summe r
Fall
Annual
0
0
0
0
0
0
0
0
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
2
0
0
5
1
2
1
1
5
1
0
0
0
1
5
A
1
2
12
(d) ASARCO Benny's (N26th & Pearl)
Winter
Spring
Summer
Fall
Annual
0
0
0
0
0
1
0
0
1
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
3
2
0
6
0
0
0
0
0
2
3
2
1
8
-------
TABLE 3-3 (Continued)
Number of Occurrences
N
NNE
E
SSE
S
ssw
SW
wsw
Total
(e) ASARCO Meeker Junior High School
Winter
Spring
Summer
Fall
Annual
0
0
1
2
3
1
2
1
3
7
0
1
0
0
1
4
1
0
3
8
0
0
0
0
0
2
1
0
1
4
1
3
3
1
8
0
0
0
0
0
8
8
5
10
31
Only the wind-direction sectors which satisfy the persistence criteria are
shown.
43
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Mixing Depths
The SHORTZ/LONGZ models define the top of the surface mixing
layer as the height at which the vertical intensity of turbulence is of the
order of 0.01 or smaller. That is, the depth of the surface mixing layer
is a function of the vertical profile of the intensity of turbulence rather
of the thermal stratification. The mixing depth is determined by a combination
of solar heating (the convective component) and mechanical turbulence (the
mechanical component). Because measurements of the vertical profile of the
intensity of turbulence are not generally available, we normally estimate
the depth of the surface mixing layer from vertical wind and temperature
profiles or from acoustic sounder data. In the simplest case, the base of
an elevated inversion layer is taken to be the top of the surface mixing
layer. It is important to recognize that, if a surface-based inversion
exists, the depth of the surface mixing layer is greater than zero because
of the presence of surface roughness elements and, in industrial or urban
areas, the presence of heat sources.
A major deficiency in the meteorological data available to develop
inputs to the SHORTZ/LONGZ models for application to the Tacoma area is the
almost complete absence of information on the depth of the surface mixing
layer. The Washington DOE takes 0700 PST or PDT soundings on week days at
Portage Bay in Seattle, approximately 45 kilometers north of the Tacoma
tideflats area. These soundings provide useful information about
conditions during the early morning hours, but caution must be exercised in
extrapolating these soundings to the remainder of the day. It is our
understanding that the Washington DOE also operates an acoustic sounder on
a continuous basis at Portage Bay, but that the acoustic sounder data are
not reduced. We believe that the acoustic sounder data could be used to
estimate hourly mixing depths which would be very useful for dispersion
model analyses.
44
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Cramer, et_ al. (1976) analyzed the twice daily Holzworth (1972)
mixing depths computed for the Seattle-Tacoma Airport during the period
1959 through 1961 to determine seasonal median early morning and afternoon
mixing depths for each combination of wind-speed and time-of-day categories.
The resulting median mixing depths are listed in Table 3-4. Cramers et al.
(1976) then estimated median mixing depths for the various combinations of
wind-speed and Pasquill stability categories (as defined by Turner, 1964)
as follows:
• The seasonal median afternoon mixing depths were
averaged and assigned to the unstable A, B and C
categories
• The seasonal median early morning mixing depths were
averaged and assigned to the combined stable E and F
categories
• The seasonal median early morning and afternoon mixing
depths were averaged and assigned to the neutral D
category
The resulting mixing depths, which are reproduced in Table 3-5, probably
are representative of average conditions in the Tacoma area and are suitable
for use in LONGZ calculations. Because of time constraints, we also used
the mixing depths in Table 3-5 to develop SHORTZ hourly meteorological
inputs for selected "worst-case" short-term periods (see Appendix C).
However, we recommend that any mixing depths that can be estimated for
these "worst-case" short-term periods from the Portage Bay soundings be
substituted for the mixing depths taken from Table 3-5.
Our examination of the 0700 PST or 0700 PDT Portage Bay vertical
temperature and wind profiles provided by PSAPCA (Anderson, 1982) for the
four air stagnation episodes during 1981 showed that they were generally
45
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TABLE 3-4
MEDIAN MIXING DEPTHS MEASURED AT THE SEATTLE-TACOMA
AIRPORT DURING THE PERIOD 1959 THROUGH 1961*
Wind Speed
(m/sec)
0 - 1.5
1.6 - 3.0
3.1 - 5.1
5.2 - 8.2
8.3 - 10.8
> 10.8
Median Mixing Depth (m)
Winter
Night
125
125
375
625
625
625
Afternoon
375
375
375
625
625
625
Spring
Night
125
375
675
875
1250
1250
Afternoon
1250
1250
1250
1250
1250
1250
Summer
Night
125
375
375
625
1250
1250
Afternoon
1250
1250
1250
1250
1250
1250
Fall
Night
125
125
375
875
875
875
Afternoon
625
875
875
875
875
875
* From Table 3-6 of the report by Cramer, et al. (1976).
TABLE 3-5
MIXING DEPTHS IN METERS*
Pasquill
Stability -
Category
A
B
C
D
E
Wind Speed (m/sec)
0.0 - 1.5
875
875
875
500
125
1.6 - 3.1
940
940
940
595
250
3.2 - 5.1
940
940
690
440
5.2 - 8.2
1000
875
8.3 - 10.8
1000
1000
>10.8
1000
1000
From Table 3-9 of the report by Cramer, et_ al. (1976)
46
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characterized by strong surface-based inversions with no clear indication
of the top of the surface mixing layer. One objective technique for calcu-
lating the mechanical component of the mixing depth that we consider to be
suitable for use with SHORTZ is given by the Benkley and Schulman (1979)
expression
H (m) Kt 100 u (m/sec) (3-1)
m
where u is the 3-hour average wind speed for the 3-hour period centered on
the hour for which the mixing depth is calculated. The measurement height
of u is at or near 10 meters above ground level.
3.2 REVIEW OF THE AVAILABLE S02 AIR QUALITY DATA
Hourly (PSAPCA) or 30-minute average (ASARCO) SO air quality
measurements are made at all of the wind measurement sites shown in Figure
3-1 except the PSAPCA Fire Station No. 12 and Willard School sites. Addi-
tionally, Kaiser measured hourly SO concentrations at its plant during the
period 4 June through 13 December 1981 and on the bluff north-northeast of
the plant during all of 1981. The locations of the Kaiser Bluff site and
Plant site S0_ monitors are shown in Figure 3-1, and Table 3-6 gives the
UTM coordinates and elevations of the two Kaiser monitoring sites, The
only 1981 SO air quality data made available to the H. E. Cramer Company
on computer tape for use in this study were the PSAPCA data and the Kaiser
data. The PSAPCA data were provided by PSAPCA (Knechtel, 1982) and the
Kaiser data were provided by Kaiser's consultant, CH2M Hill (Caniparoli,
1982). We first used MAQSAP with the N26th & Pearl hourly wind and SO
concentration data as a check on our previous conclusion (Cramers et alo,
1976) that the N26th & Pearl winds are the best available indicator of
transport winds for emissions from the ASARCO Main Stack. We then used
MAQSAP with several combinations of wind data and Kaiser SO concentra-
tion data to gain insight into the winds that are most representative of
transport winds for emissions from the tideflats sources.
47
-------
TABLE 3-6
UNIVERSAL TRANSVERSE MERCATOR (UTM) COORDINATES AND ELEVATIONS
ABOVE MEAN SEA LEVEL (MSL) OF THE KAISER BLUFF AND
PLANT SITE SO AIR QUALITY MONITORS
Site
Kaiser Bluff Site
Kaiser Plant Site
Coordinates
UTM X (km)
548.400
547.575
UTM Y (km)
5,235.410
5,234.190
Ground Elevation
(m MSL)
125
3
48
-------
Annual Average S00 Concentrations
MAQSAP uses hourly wind and SO concentration measurements to
determine the annual average SO concentration for each combination of
wind-direction and time-of-day categories. For our first set of MAQSAP
analyses, we merged the hourly SO concentration measurements from the
PSAPCA N26th& Pearl site with the concurrent hourly wind data from: (1)
the PSAPCA N26th & Pearl site, and (2) the ASARCO Benny's (N26th & Pearl)
site. The 1981 annual average SO concentrations at the PSAPCA N26th &
Pearl site are given by PSAPCA N26th & Pearl and ASARCO Benny's (N26th &
Pearl) wind directions in Tables 3-7 and 3-8, respectively. The two tables
consider only the hours with valid SO concentration measurements and do
not attempt to account for the 660 hours of missing concentration data. As
shown by the average concentrations at the bottom of each table, the highest
1981 average concentration at N26th & Pearl occurred during the afternoon
and the lowest average concentration occurred at night. The average concen-
tration for each wind direction varies, depending on the wind data used in
the MAQSAP analysis. This variation is illustrated in Figure 3-12, which
shows the annual pollution roses (annual average concentrations in parts
per billion (ppb) for each wind-direction sector). North-northeast winds
are required for the straight-line transport of ASARCO emissions to N26th &
Pearl, while east and east-southeast winds are required for the straight-
line transport of emissions from the tideflats sources to N26th & Pearl.
As shown by Figure 3-12, the ASARCO Benny's wind directions appear to be
more representative of these source-receptor relationships than the PSAPCA
N26th & Pearl wind directions. However, it is important to note that the
wind direction required for the straight-line transport of ASARCO emissions
to N26th and Pearl is near the boundary between the standard 22.5-degree
sectors for north and north-northeast winds, Consequently, an alternate
interpretation of the almost identical average concentrations with north
and north-northeast winds at the PSAPCA N26th & Pearl site is that the
PSAPCA N26th & Pearl wind directions are more representative of transport
wind directions for ASARCO emissions than are the Benny's wind directions
49
-------
TABLE 3-7
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE PSAPCA N26TH & PEARL
SITE BY PSAPCA N26TH & PEARL WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Average
Annual Average SO Concentration (ppm)
Night
0.0210
0.0225
0.0099
0.0098
0.0102
0.0088
0.0067
0.0036
0.0019
0.0013
0.0011
0.0011
0.0023
0.0050
0.0033
0.0111
0.0071
Morning
0.0348
0.0212
0.0103
0.0138
0.0115
0.0125
0.0029
0.0029
0.0024
0.0009
0.0018
0.0028
0.0040
0.0037
0.0200
0.0280
0.0084
Afternoon
0.0340
0.0319
0.0212
0.0138
0.0060
0.0071
0.0010
0.0031
0.0025
0.0012
0.0011
0.0015
0.0032
0.0158
0.0261
0.0265
0.0120
Evening
0.0211
0.0313
0.0095
0.0117
0.0207
0.0073
0.0087
0.0054
0.0021
0.0022
0.0007
0.0010
0.0017
0.0044
0.0080
0.0050
0.0106
Average
0.0287
0.0273
0.0130
0.0114
0.0112
0.0088
0.0055
0.0036
0.0021
0.0013
0.0011
0.0015
0.0028
0.0124
0.0190
0.0187
0.0092
50
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TABLE 3-8
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE PSAPCA N26TH & PEARL
SITE BY ASARCO BENNY'S (N26TH & PEARL) WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
w
WNW
NW
NNW
Average
Annual Average SO- Concentration (ppm)
Night
0.0199
0.0258
0.0125
0.0109
0.0121
0.0083
0.0074
0.0045
0.0024
0.0019
0.0009
0.0016
0.0028
0.0043
0.0067
0.0092
0.0071
Morning
0.0239
0.0361
0.0148
0.0154
0.0139
0.0489
0.0085
0.0046
0.0034
0.0016
0.0013
0.0024
0.0046
0.0067
0.0150
0.0233
0.0084
Afternoon
0.0315
0.0355
0.0253
0.0243
0.0073
0.0083
0.0076
0.0031
0.0026
0.0018
0.0012
0.0016
0.0069
0.0113
0.0275
0.0195
0.0120
Evening
0.0173
0.0331
0.0182
0.0152
0.0185
0.0062
0.0080
0.0092
0.0030
0.0026
0.0013
0,0015
0,0013
0,0083
0.0037
0.0114
0.0106
Average
0.0253
0.0318
0.0172
0.0142
0.0127
0.0116
0.0077
0.0048
0.0026
0.0019
0.0011
0.0017
0,0048
0.0088
0.0185
0.0150
0.0092
51
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PSAPCA N26th a PEARL SITE AVERAGE S02 CONCENTRATION (ppb) BY =
PSAPCA N26th & PEARL WIND DIRECTION
ASARCO BENNY'S (N26th a PEARL) WIND DIRECTION
NNW N NNE
NE
WNW
W
WSW
-10:
ENE
-30-
ESE
SW
SSW
SSE
SE
Figure 3-12. PSAPCA N26th & Pearl site 1981 average SO concentrations in
parts per billion (ppb) by PSAPCA N26th & Pearl and ASARCO
Benny's (N26th & Pearl) wind directions. Directions are
directions from which the wind is blowing, and the
concentration scale in ppb is shown at the right center of
the figure.
52
-------
(Carson, 1982). An unexpected result shown in Figure 3-12 is that the
average of the hourly concentrations measured at N26th & Pearl during the
hours when northwest winds were measured by either of the two N26th & Pearl
wind sensors exceeds the average concentrations when east and eastsoutheast
winds were measured. Because we know of no significant SCL source
northwest of N26th & Pearl, we do not have any simple explanation for the
occurrence of a high average concentration with northwest winds.
It is important to note that the differences in the two N26th &
Pearl site pollution roses developed using the PSAPCA N26th & Pearl and
ASARCO Benny's (N26th & Pearl) wind data (see Figure 3-12) are much larger
than the differences in the annual wind-direction distributions shown in
Figure 3-6. We conclude from this result that, although there is a close
average correspondence between the two N26th & Pearl wind-direction measure-
ments, there often are appreciable differences between the concurrent hourly
wind directions.
To evaluate the representativeness of the ASARCO Benny's (N26Lh &
Pearl) and Meeker winds of transport winds in the tideflats area, we merged
these winds with the concurrent Kaiser Bluff site hourly S0_ concentrations
for use in our second set of MAQSAP analyses. The 1981 annual average
SO concentrations at the Kaiser Bluff site are given by ASARCO Benny's
(N26th & Pearl) and ASARCO Meeker wind directions in Tables 3-9 and 3-10,
respectively. Unlike the average concentrations by time-of-day category at
N26th & Pearl, the average concentrations at the bottoms of Tables 3-9 and
3-10 show that there is essentially no diurnal variation in average concen-
tration at the Bluff site. The Bluff site pollution roses shown in Figure
3-13 also reveal unexpected features. West-northwest winds are required
for the straight-line transport to the Bluff site of ASARCO emissions,
while south-southwest through west-southwest winds are required for the
straight-line transport to the Bluff site of emissions from the tideflats
sources. The pollution roses developed using the ASARCO Benny's and Meeker
wind data both show the expected influence of ASARCO emissions during hours
with west-northwest winds. Also, the pollution rose based on the Meeker
53
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TABLE 3-9
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE KAISER BLUFF
SITE BY ASARCO BENNY'S (N26TH & PEARL) WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Average
Annual Average SO Concentration (ppm)
Night
0.0093
0.0055
0.0059
0.0044
0.0043
0.0060
0.0063
0.0056
0.0058
0.0059
0.0097
0.0102
0.0160
0.0171
0.0091
0.0109
0.0086
Morning
0.0149
0.0108
0.0076
0.0074
0.0093
0.0155
0.0016
0.0067
0.0057
0.0067
0.0094
0.0147
0.0187
0.0160
0.0157
0.0182
0.0102
Afternoon
0.0066
0.0051
0.0056
0.0086
0.0048
0.0085
0.0070
0.0055
0.0070
0.0072
0.0083
0.0088
0.0159
0.0205
0.0175
0.0097
0.0091
Evening
0.0046
0.0052
0.0055
0.0110
0.0067
0.0076
0.0101
0.0094
0.0060
0.0076
0.0082
0.0083
0.0106
0.0112
0.0163
0.0108
0.0086
Average
0.0079
0.0058
0.0061
0.0064
0.0053
0.0067
0.0064
0.0060
0.0060
0.0065
0.0090
0.0096
0.0158
0.0182
0.0154
0.0115
0.0090
54
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TABLE 3-10
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE KAISER BLUFF
SITE BY ASARCO MEEKER WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Average
Annual Average S0? Concentration (ppm)
Night
0.0074
0.0664
0.0094
0.0121
0.0132
0.0157
0.0086
0.0055
0.0065
0.0092
0.0084
0.0081
0.0060
0.0122
0.0099
0.0082
0.0086
Morning
0.0093
0.0062
0.0070
0.0085
0.0101
0.0101
0.0100
0.0095
0.0105
0.0112
0.0099
0.0131
0.0156
0.0142
0.0128
0.0133
0.0102
Afternoon
0.0055
0.0052
0.0092
0.0057
0.0061
0.0065
0.0107
0.0075
0.0096
0.0106
0.0070
0.0077
0.0128
0.0192
0.0159
0.0099
0.0091
Evening
0.0094
0.0056
0.0106
0.0188
0.0091
0.0118
0.0142
0.0061
0.0067
0.0102
0.0054
0.0079
0..0059
0.0060
0.0179
0.0062
0.0086
Average
0.0070
0.0058
0.0094
0.0127
0.0119
0.0146
0.0094
0.0066
0.0083
0.0101
0.0075
0.0085
0.0114
0.0171
0.0149
0.0096
0.0090
55
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KAISER BLUFF SITE AVERAGE S02 CONCENTRATION (ppb) BY'
ASARCO BENNY'S (N26th a PEARL) WIND DIRECTION
ASARCO MEEKER WIND DIRECTION
NNWN NNE
NE
WNW
W
WSW
ENE
-30-
ESE
SW
SSW
SSE
SE
Figure 3-13. Kaiser Bluff site 1981 average SO concentrations in parts
per billion (ppb) by ASARCO Benny^s (N26th & Pearl) and
Meeker wind directions. Directions are directions from
which the wind is blowing, and the concentration scale in
ppb is shown at the right center of the figure.
56
-------
wind data shows a peak with south-southwest winds that may be attributable
to emissions from the Kaiser plant. However, the pollution rose based on
the Meeker wind data shows unexpected high average concentrations assoc-
iated with winds from the northeast through southeast. We do not know of
any SO- sources in the sector northeast through southeast of the Bluff
site that can account for these relatively high average concentrations. One
hypothesis to explain the occurrence of relatively high average concen-
trations with easterly winds at the Meeker site is that SO previously
emitted by one or more of the sources in or adjacent to the tideflats
area (for example, the ASARCO smelter) are advected back over the Bluff
site following a wind shift.
Our third set of MAQSAP analyses merged the hourly SO concen-
trations from the Kaiser Plant site with the concurrent hourly wind data
from: (1) the PSAPCA Fire Station No. 12 site, and (2) the ASARCO Benny's
(N26th & Pearl) site. The 1981 annual average S0_ concentrations at the
Kaiser Plant site are given by PSAPCA Fire Station No. 12 and ASARCO Benny's
(N26th & Pearl) wind directions in Tables 3-11 and 3-123 respectively,, 4s
shown by the average concentrations at the bottom of each table, there are
no clear diurnal trends. Assuming the average Plant site concentration for
the approximate 6-month period of record to be representative of an annual
average concentration, the Plant site annual average concentration of Oo0186
ppm is approximately double the annual average concentrations at the PSAPCA
N26th & Pearl site and the Kaiser Bluff site. Also, the average concentra-
tion at the Plant site is very near the PSAPCA and Washington State annual
ambient air quality standard of 0.02 ppm. The Plant site pollution roses
based on the Fire Station No. 12 and Benny's wind data are shown in Figure
3-14. (We point out that the scale of Figure 3-14 differs from the scale
used in Figures 3-12 and 3-13 because of the much higher average concentra-
tions at the Plant site.) The dry scrubber system stacks of Kaiser Line 4
are about 200 meters south of the Plant site monitor, and both pollution
roses show the expected high average concentration with south winds. Both
pollution roses also show the expected presence of ASARCO emissions with
west-northwest winds. However, both pollution roses show average
concentrations with winds from the east through south-southeast that are
57
-------
TABLE 3-11
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE KAISER PLANT SITE
BY PSAPCA FIRE STATION NO. 12 WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
A
Annual Average S0? Concentration (ppm)
Night Morning
1
0.0107
0.0097
0.0119
0.0116
I
E
ESE
SE
SSE
S
ssw
sw
wsw
w
WNW
NW
NNW
Average
0.0199
0.0244
0.0200
0.0230
0.0473
0.0341
0.0109
0.0094
0.0072
0.0069
0.0078
0.0075
0.0185
0.0132
0.0091
0.0097
0.0193
0.0210
0.0243
0.0209
0.0199
0.0658
0.0322
0.0112
0.0096
0.0083
0.0261
0.0157
0.0133
0.0224
Afternoon
0.0124
0.0108
0.0105
0.0380
0.0168
0.0158
0.0309
0.0326
0.0474
0.0370
0.0117
0.0073
0.0068
0.0117
0.0176
0.0162
0.0172
Evening
0.0115
0.0098
0.0153
0.0080
0.0246
0.0255
0.0334
0.0331
0.0511
0.0417
0.0090
0.0077
0.0060
0.0100
0.0098
0.0096
0.0188
Average
0.0121
0.0099
0.0120
0.0136
0.0204
0.0237
0.0218
0.0247
0.0513
0.0355
0.0110
0.0082
0.0068
0.0115
0.0142
0.0139
0.0186
The period of record for the SO concentrtation measurements is 1400 PST
on 4 June through 2400 PST on 13 December.
58
-------
TABLE 3-12
1981 ANNUAL AVERAGE SO CONCENTRATION AT THE KAISER PLANT SITE
SITE BY ASARCO BENNY'S (N26TH & PEARL) WIND DIRECTION
Wind Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Average
Annual Average SO Concentration (ppm)
Night
0.0099
0.0122
0.0131
0.0167
0.0185
0.0201
0.0198
0.0225
0.0279
0.0333
0.0168
0.0099
0.0097
0.0118
0.0100
0.0106
0.0185
Morning
0.0194
0.0213
0.0181
0.0201
0.0310
0.0335
0.0267
0.0204
0.0464
0.0403
0.0142
0.0126
0.0144
0.0204
0.0180
0.0200
0.0224
Afternoon
0.0103
0.0106
0.0117
0.0223
0.0252
0.0286
0.0329
0.0280
0.0384
0.0409
0.0142
0.0134
0,0224
0.0250
0.0190
0.0134
0.0172
Evening
0.0087
0.0100
0.0088
0.0142
0.0189
0.0383
0.0222
0.0322
0.0421
0.0468
0.0140
0.0105
0,0133
0.0108
0.0144
0.0098
0.0188
Average
0.0103
0.0118
0.0131
0.0180
0.0207
0.0259
0.0234
0.0240
0.0338
0.0373
0.0151
0.0122
0.0169
0.0204
0.0164
0.0121
0.0186
The period of record for the SO. concentration measurements is 1400 PST
on 4 June through 2400 PST on 13 December.
59
-------
KAISER PLANT SITE AVERAGE S02 CONCENTRATION (ppb) BY:
PSAPCA FIRE STATION No. 12 WIND DIRECTION
ASARCO BENNY'S (N26th a PEARL) WIND DIRECTION
NW NNW N NNE
NE
WNW
W
WSW
ENE
JO 60-
ESE
SW
SSW
SSE
SE
Figure 3-14. Kaiser Plant site 1981 average SO concentrations in parts
per billion (ppb) by PSAPCA Fire Station No. 12 and ASARCO
Benny's (N26th & Pearl) wind directions. Directions are
directions from which the wind is blowing, and the
concentration scale in ppb is shown at the right center of
the figure. Note that the scale of this figure differs from
the scale of Figures 3-12 and 3-13.
60
-------
higher than the average concentrations with winds from the west-northwest.
Roof monitor emissions from Kaiser Line 4 and/or from the dry scrubber
stacks of Lines 1 and 2 may be the cause of the relatively high average
concentrations at the plant site that are associated with hours of easterly
winds over the tideflats area.
Hourly SO Concentrations
Table 3-13 lists the number of 1981 occurrences at the PSAPCA
N26th & Pearl site of hourly S0? concentrations above 0.10 ppm, classified
by time of day and PSAPCA N26th & Pearl and ASARCO Benny's (N26th & Pearl)
wind directions. Approximately 60 percent of the 92 cases occurred during
the afternoon time-of-day category, 18 percent occurred during the night
time-of-day category and 11 percent occurred during each of the transition
(morning and evening) time-of-day categories. Also, over 70 percent of the
cases occurred during hours when the PSAPCA N26th & Pearl and ASARCO Benny's
wind directions were north to northeast. These results strongly suggest
that emissions from the ASARCO smelter are principally responsible for the
occurrence of the highest hourly SO concentrations in the residential area
of the Tacoma peninsula. If the PSAPCA N26th & Pearl wind directions are
assumed to be representative of transport wind directions, only one of the
92 cases can be attributed to emissions from the tideflats sources, which
are located to the east and east-southeast. Similarly, if the ASARCO Benny's
wind directions are assumed to be representative of transport wind directions,
only two of the cases can be attributed to emissions from the tideflats
sources. However, the wind speeds for these easterly wind cases were so
low (on the order of 1 meter per second) that the reported PSAPCA and ASARCO
wind directions are not necessarily representative of the transport wind
directions. It is of interest to note that the peak in the N26th & Pearl
pollution rose with northwest winds (see Figure 3-12) is also reflected by
the number of hourly concentrations above 0.10 ppm.
We conclude from the almost complete absence of hourly concentrations
above 0.10 ppm associated with the wind directions required to transport
emissions from the tideflats sources to the N26th & Pearl site that these
61
-------
TABLE 3-13
NUMBER OF 1981 OCCURRENCES AT THE PSAPCA N26TH & PEARL SITE OF HOURLY
SO CONCENTRATIONS ABOVE 0.10 PPM BY PSAPCA N26TH & PEARL AND
ASARCO BENNY'S (N26TH & PEARL) WIND DIRECTIONS
Wind
Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
SSW
SW
WSW
W
WNW
NW
NNW
Calm or
Msg Winds
Total
No. of Hourly Concentrations Above 0.10 ppm
Night
PSAPCA
N26th &
Pearl
4
7
1
0
0
0
0
0
0
0
0
0
0
0
0
0
5
17
ASARCO
Benny' s
2
5
2
2
0
0
0
0
0
1
0
0
0
0
0
0
5
17
Morning
PSAPCA
N26th &
Pearl
2
2
1
0
0
0
0
0
0
0
0
0
0
0
1
0
4
10
ASARCO
Benny' s
0
5
2
1
0
1
0
0
0
0
0
0
0
0
0
1
0
10
Afternoon
PSAPCA
N26th &
Pearl
15
18
6
0
0
0
0
0
0
0
0
0
0
3
4
1
8
55
ASARCO
Benny' s
12
20
10
2
0
0
0
0
0
0
0
0
3
2
6
0
0
55
Evening
PSAPCA
N26th &
Pearl
1
8
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
10
ASARCO
Benny' s
0
7
2
0
1
0
0
0
0
0
0
0
0
0
0
0
0
10
Total
PSACPA
N26th &
Pearl
22
35
8
0
1
0
0
0
0
0
0
0
0
3
5
1
17
92
ASARCO
Benny1 s
14
37
16
5
1
1
0
0
0
1
0
0
3
2
6
1
5
92
-------
emissions rarely- if ever, cause relatively high short-term SO. concentrations
on the elevated terrain of the Tacoma peninsula. This conclusion is supported
by the PSAPCA air quality measurements made during the period 1 July through
23 November 1980 when the ASARCO smelter was closed by a strike. PSAPCA
reviewed the air quality data from the PSAPCA monitors at N26th & Pearl,
N37th & Vassault (southwest of the ASARCO smelter), Maury Island (north-
northeast of the ASARCO smelter) and Federal Way and found that (Knechtel,
1982):
During the period ASARCO was not in operation, only 1
hour exceeding 0.05 ppm at any of the four stations was
located. This was a value of 0.06 ppm at North 26th
and Pearl accompanied by easterly winds.
Table 3-14 lists the number of 1981 occurrences at the Kaiser
Bluff site of hourly S0? concentrations above 0.10 ppm, classified by time
of day and ASARCO Benny's (N26th & Pearl) and Meeker wind directions.
During our examination of the Kaiser Bluff site concentration data, we
noted that an hourly concentration of 0.16 ppm was reported at 2100 PST on
each day of the period 3 through 9 March 1981. These seven concentrations
above 0.10 ppm are not included in Table 3-14 because we believe they reflect
calibration checks which were inadvertently included as valid data. In
contrast to the N26th & Pearl results, Table 3-14 shows that 61 percent of
the 28 cases remaining after the deletion of the invalid cases occurred
during the night time-of-day category, 21 percent of the cases occurred
during the evening time-of-day category and 18 percent of the cases occurred
during the afternoon time-of-day category. According to Table 3-14, hourly
concentrations above 0.10 ppm at the Bluff site are most frequently associated
with calm, missing or variable winds at the ASARCO Benny's site and with
light winds from the east through east-southeast at the ASARCO Meeker site.
Table 3-14 does not provide any indication that the highest short-term
concentrations at the Bluff site are caused by the approximate straight-line
transport of emissions from ASARCO, Kaiser or any of the other tideflats
sources if the ASARCO Meeker winds are assumed to be representative of
transport winds. However, all but one of the cases without calm or missing
63
-------
TABLE 3-14
NUMBER OF 1981 OCCURRENCES AT THE KAISER BLUFF SITE OF HOURLY
SO CONCENTRATIONS ABOVE 0.10 PPM BY ASARCO BENNY'S
(N26TH & PEARL) AND MEEKER WIND DIRECTIONS
Wind
Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
ssw
sw
wsw
w
WNW
NW
NNW
Calm or
Msg Winds
Total
No. of Hourly Concentrations Above 0.10 ppm
Night
ASARCO
Benny' s
0
0
0
0
0
0
0
0
0
0
2
2
2
0
0
0
11
17
ASARCO
Meeker
0
1
0
2
3
8
2
0
0
0
0
0
0
0
0
1
0
17
Morning
ASARCO
Benny ' s
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
ASARCO
Meeker
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Afternoon
ASARCO
Benny ' s
0
0
0
0
0
0
0
0
0
0
0
0
2
2
1
0
0
5
ASARCO
Meeker
0
0
0
0
0
0
0
0
0
0
0
0
0
3
2
0
0
5
Evening
ASARCO
Benny ' s
0
0
0
1
0
0
0
0
0
0
0
1
0
0
1
1
2
6
ASARCO
Meeker
2
0
2
1
0
0
1
0
0
0
0
0
0
0
0
0
0
0
Total
ASARCO j ASARCO
Benny' s
0
0
0
1
0
0
0
0
0
0
2
3
4
2
2
1
13
28
vleeker
2
1
2
3
3
8
3
0
0
0
0
0
0
3
2
1
0
28
-------
winds at the ASARCO Benny's site are associated with very light westerly
winds, and these cases are possibly attributable to emissions from ASARCO
and the sources within the tideflats.
Table 3-15 lists the number of 1981 occurrences at the Kaiser
Plant site of hourly SO concentrations above 0.10 ppm, classified by time
of day and PSAPCA Fire Station No. 12 and ASARCO Benny's (N26th & Pearl)
wind directions. The 43 cases are equally distributed among the four time-
of-day categories. Approximately 84 percent of the cases are associated
with south or south-southwest winds at Fire Station No. 12 and Benny's.
The Kaiser Plant site SO. monitor is located on the plant property due
north of the dry scrubber stacks for Kaiser Line 4. Assuming the majority
of the hourly concentrations above 0.10 ppm at the Plant site to be attri-
butable to emissions from these stacks, the results presented in Table 3-15
suggest that the Fire Station No. 12 wind directions may be more represen-
tative of the winds in the vicinity of the Kaiser plant during periods of
southerly flow than are the Benny's winds. Only four of the 43 cases
occurred with Benny's winds from the west through northwest, the directions
required for the straight-line transport of emissions from ASARCO and the
sources within the tideflats to the Plant site monitor. Although the hours
with east-southeast winds at Fire Station No. 12 and Benny's are associated
with a relatively high annual average concentration at the Kaiser Plant
site, Table 3-15 shows that the concentrations during these hours are all
less than 0.10 ppm.
3.3 EXAMINATION OF SELECTED SHORT-TERM PERIODS
The focus of our evaluation of concurrent meteorological, emissions
and SO air quality data was placed on cases when emissions from sources
within the tideflats (rather than emissions from the ASARCO smelter) are
most likely to have affected the observed SO concentrations. The air
quality monitors most likely to measure SO concentrations attributable to
emissions from the sources within the tideflats are the Kaiser Plant and
65
-------
TABLE 3-15
NUMBER OF 1981 OCCURRENCES AT THE KAISER PLANT SITE OF HOURLY
SO CONCENTRATIONS ABOVE 0.10 PPM BY PSAPCA FIRE STATION NO.
AND ASARCO BENNY'S (N26TH & PEARL) WIND DIRECTIONS
12
Wind
Direction
(Sector)
N
NNE
NE
ENE
E
ESE
SE
SSE
S
ssw
sw
wsw
w
WNW
NW
NNW
Calm or
Msg Winds
Total
*
No. of Hourly Concentrations Above 0.10 ppm
Night
PSAPCA
Fire
Stn. 12
0
0
0
0
0
0
0
0
9
1
0
1
0
0
0
0
0
11
ASARCO
Benny1 s
0
0
0
0
0
0
0
0
3
7
1
0
0
0
0
0
0
11
Morning
PSAPCA
Fire
Stn. 12
0
0
0
0
0
0
0
0
10
1
0
0
0
0
0
0
0
11
ASARCO
Benny' s
0
0
0
0
0
0
0
0
6
5
0
0
0
0
0
0
0
11
Afternoon
PSAPCA
Fire
Stn. 12
0
0
0
0
0
0
0
0
2
5
0
0
0
0
1
2
1
11
ASARCO
Benny' s
0
0
0
0
0
0
0
0
1
5
1
0
2
1
1
0
0
11
Evening
PSAPCA
Fire
Stn. 12
0
0
0
0
0
0
0
0
6
2
0
0
0
0
0
0
2
10
ASARCO
Jenny' s
0
0
0
0
0
0
0
0
3
6
0
1
0
0
0
0
0
10
Total
1
PSACPA
Fire
Stn. 12
0
0
0
0
0
0
0
0
27
9
0
1
0
0
1
2
3
43
ASARCO
Benny ' s
0
0
0
0
0
0
0
0
13
23
2
1
2
1
1
0
0
43
The period of record for the SO. concentration measurements is 1400 PST on 4 June through 2400 PST
on 13 December.
-------
Bluff sites and, to a lesser extent, the ASARCO Meeker site. Although time
constraints prevented the completion of this task, our analysis partially
answered the following questions:
1. For the existing sources, are the SO concentrations
calculated by SHORTZ at the Kaiser Bluff site during
hours of moderate or strong south-southwest winds con-
sistent with the observed concentrations?
2. For the existing sources, are the SO concentrations
calculated by SHORTZ at the Kaiser Plant site during
hours of moderate or strong south and south-southwest
winds consistent with the observed concentrations?
Additionally, at the specific request of PSAPCA, we reviewed the meteorolo-
gical, emissions and air quality data available for each 1981 "air stagnation
episode" (each period during 1981 for which the National Weather Service
issued an Air Stagnation Advisory). Our review of the air stagnation epi-
sodes included trial SHORTZ calculations as well as a trial calculation
with LONGZ as an air stagnation fumigation model (see Section 4.1 of Cramer,
_et__al. , 1976).
Kaiser Bluff Site
As noted in Section 3.2, the highest hourly SO concentrations
measured at the Kaiser Bluff site occur during the night, evening or after-
noon time-of-day categories with very light winds. The ASARCO Meeker wind
directions during these hours are almost always from the northeast through
the southeast, while the ASARCO Benny's (N26th & Pearl) winds do not show
any clear trends. The wind speeds during and before these hours are so
light that the available wind directions generally cannot be expected to be
reliable indicators of transport wind directions within the surface mixing
layer. We hypothesize that these isolated 1-hour to 4-hour periods of
relatively high hourly SO concentrations (concentrations greater than or
equal to 0.15 ppm) are attributable to previously emitted emissions which
67
-------
are advected back over the area following a wind shift. These emissions
could come from any source or combination of sources, but the magnitude of
the ASARCO stack emissions in comparison with the magnitude of the emissions
from the other sources suggests that the ASARCO stack emissions are the
most probable cause. Because of the light wind speeds during the hours
before the hours with the highest hourly concentrations at the Bluff site,
we point out that the emissions which cause these concentrations may have
been emitted 12 or more hours before the onset of the high observed concen-
trations.
Our analysis of the meteorological data discussed in Section 3.1
suggests that the highest 24-hour average SO^ concentrations attributable
to Kaiser's potential emissions from the currently unused 152-meter stack
are likely to occur on the bluff during periods of persistent moderate-to-
strong south-southwest or southwest winds. However, because of the short
heights of the Kaiser stacks in current use, we would expect relatively low
hourly concentrations at the Bluff site under these meteorological conditions.
We used our persistence search (PRSIST) data analysis program with the 1981
ASARCO Benny's (N26th & Pearl) wind data to isolate all periods when winds
above 3.1 meters per second persisted within any 25-degree sector for 6 or
more hours. We then examined the Kaiser Bluff site SO concentration data
for the south-southwest and southwest wind cases and found that the observed
hourly concentrations varied from zero to about 0.03 ppm. Finally, we used
SHORTZ with the 1981 average emissions parameters given in Section 2 and
with hourly meteorological inputs developed following the procedures outlined
in Section 5 to calculate hourly SO concentrations at the Bluff site for
30 March 1981.
Table 3-16 compares the calculated and observed hourly SO concen-
trations at the Kaiser Bluff site on 30 March 1981. The hour-to-hour
correspondence between the observed and calculated concentrations is poor,
a result that is expected because of the extreme sensitivity of hourly
concentrations calculated at fixed locations to slight uncertainties in the
transport wind direction (see Appendix E of Cramer, _££ _a.l. , 1976). However,
68
-------
TABLE 3-16
COMPARISON OF OBSERVED AND CALCULATED SO CONCENTRATIONS
AT THE KAISER BLUFF SITE ON 30 MARCH 1981
Hour
(PST)
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Average
SO Concentration (ppm)
^*
Observed Calculated
0.01
0.01
0.03
0.03
0.02
0.01
0.03
0.02
0.02
0.01
0.01
0.00
0.01
0.02
0.02
0.01
0.00
0.00
MSG
MSG
MSG
0.00
0.00
0.00
0.012
0.00
0.00
0.00
0.00
0.00
0.00
0.03
0.00
0.07
0.07
0.05
0.10
0.06
0.00
0.06
0.04
0.00
0.03
0.02
0.11
0.03
0.03
0.05
0.00
0.031
Ratio of Calculated
and Observed
Concentrations
0.00
0.00
0.00
0.00
0.00
0.00
1.00
0.00
3.50
7.00
5.00
oo
6.00
0.00
3.00
4.00
0.00
OO
—
—
—
oo
oo
0.00
2.58
Difference Between
Observed and Calculated
Concentrations (ppm)
0.01
0.01
0.03
0.03
0.02
0.01
0.00
0.02
-0.05
-0.06
-0.04
-0.10
-0.05
0.02
-0.04
-0.03
0.00
0.00
—
' —
—
0.03
0.05
0.00
0.019
69
-------
it should be noted that the observed and calculated hourly SO concentra-
tions are also relatively small. For example, the maximum difference
between observed and calculated hourly concentrations paired in space and
time is only 0.10 ppm. It is also important to note that the observed
24-hour average concentration on 30 March of 0.012 ppm is a factor of 7.3
lower than the highest 24-hour running mean concentration of 0.082 ppm
(24-hour period ending at 0100 PST on 3 November 1981). We conclude that:
(1) The ASARCO Benny's winds are not necessarily representative of the
winds affecting the initial transport and dispersion of emissions from the
existing Kaiser sources during periods of persistent moderate-to-strong
south-southwest winds; and, (2) The hourly and 24-hour average concentra-
tions calculated for the Bluff site during periods of persistent moderate-
to-strong south-southwest winds are lower than the hourly and 24-hour
average concentrations that occur at these sites under other meteorological
conditions. For these reasons, we believe that caution should be exercised
in interpreting the concentrations calculated on the elevated terrain of
the bluff for emissions from the tideflats sources with short stacks.
Based on our previous experience in testing SHORTZ (for example, Bowers, et
al. , 1980), we believe that the concentrations calculated on the bluff for
emissions from the Kaiser and Tacoma City Light tall stacks are more likely
to be representative of actual concentrations than the concentrations
calculated for emissions from the short stacks.
Kaiser Plant Site
The analysis of meteorological and air quality data discussed in
Section 3.2 indicates that the highest hourly concentrations at the Kaiser
Plant site occur with winds from the south or south-southwest. We selected
10 December 1981 to test SHORTZ at the plant site for two reasons. First,
hourly concentrations above 0.10 ppm were measured at the Plant site during
6 of the 22 hours for which concentration measurements are available.
Second, moderate-to-strong south to south-southwest winds persisted through-
out the day at the ASARCO Benny's (N26th & Pearl) and PSAPCA Fire Station
No. 12 sites. These wind directions suggest that the hourly SO concentra-
70
-------
tions measured at the Kaiser Plant and Bluff sites probably are attributable
to emissions from the Kaiser Plant, while the hourly concentrations measured
at the ASARCO Meeker site probably are attributable to emissions from the
St. Regis Mill.
We used SHORTZ with the 1981 average emissions parameters given
in Section 2 for the Kaiser and St. Regis plants to calculate hourly and
24-hour average SO concentrations at the Kaiser Plant and Bluff sites and
the ASARCO Meeker site. To evaluate the representativeness of the Benny's
and Fire Station No. 12 winds, we used both sets of wind observations in
the SHORTZ calculations for 10 December. Because the hourly wind speeds at
Fire Station No. 12 generally exceeded the corresponding wind speeds at
Benny's on 10 December, we assumed the wind speed to be independent of
height in both sets of SHORTZ calculations. From the Portage Bay 0700 PST
sounding provided by PSAPCA (Anderson, 1982), we estimated the top of the
surface mixing layer to be about 500 meters above mean sea level with a
vertical potential temperature gradient within the mixing layer of about
0.003 degrees Kelvin per meter. These values were assumed to exist through-
out the day because of the moderate-to-strong wind speeds. Following the
Turner (1964) definitions of the Pasquill stability categories, the neutral
D category existed at McChord Air Force Base during all hours except 0300
and 0400 PST when E and F stability existed. We used the SHORTZ default
rural turbulent intensities for these stability categories except that F
stability was redefined as E stability for the reasons given by Cramer, ej_
al. (1976).
The SO concentrations observed at the Kaiser Bluff and Plant
sites and the ASARCO Meeker site on 10 December 1981 are compared with the
hourly S09 concentrations calculated by SHORTZ using Benny's and Fire
Station No. 12 winds in Tables 3-17 and 3-18, respectively. As expected,
both tables show a poor hour-to-hour correspondence between observed and
calculated concentrations. If the Benny's winds are used in the model
calculations, the relatively low 24-hour average concentration measured at
the Kaiser Bluff site is overprecited by a factor of 6.83, while the
71
-------
TABLE 3-17
COMPARISON OF THE OBSERVED HOURLY SO CONCENTRATIONS ON
10 DECEMBER 1981 WITH THE CONCENTRATIONS CALCULATED
USING ASARCO BENNY'S (N26TH & PEARL) WINDS
Hour
(PST)
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Average
Observed
Concentration
(ppni)
Kaiser
Bluff
0.02
0.00
0.00
0.00
0.00
MSG
MSG
0.00
0.00
0.00
0.01
0.00
0.00
0.01
0.02
0.00
0.00
0.01
0.01
0.01
0.01
0.00
0.01
0.01
0.006
Kaiser
Plant
0.04
0.11
0.02
0.15
0.10
0.10
0.01
0.15
MSG
MSG
0.07
0.15
0.11
0.06
0.04
0.11
0.08
0.07
0.07
0.07
0.05
0.05
0.04
0.04
0.077
ASARCO
Meeker
0.00
0.01
0.00
0.00
0.01
0.00
0.01
0.01
0.00
0.01
0.01
0.00
0.01
0.00
0.00
0.00
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.003
Calculated
Concentration
(ppm)
Kaiser
Bluff
0.06
0.00
0.00
0.00
0.03
0.00
0.00
0.00
0.03
0.13
0.01
0.00
0.02
0.03
0.10
0.12
0.08
0.01
0.06
0.13
0.04
0.01
0.08
0.03
0.041
Kaiser
Plant
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.000
ASARCO
Meeker
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.01
0.00
0.000
Ratio of Calculated
and Observed
Concentrations
Kaiser
Bluff
3.00
—
—
—
CO
MSG
MSG
—
00
CO
1.00
—
CO
3.00
5.00
oo
CO
1.00
6.00
13.00
4.00
OO
8.00
3.00
6.83
Kaiser
Plant
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
MSG
MSG
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
ASARCO
Meeker
__
0.00
—
—
0.00
—
0.00
0.00
—
0.00
0.00
—
0.00
—
—
—
0.00
—
__
—
—
CO
0.00
0.00
72
-------
TABLE 3-18
COMPARISON OF THE OBSERVED HOURLY SO CONCENTRATIONS ON
10 DECEMBER 1981 WITH THE CONCENTRATIONS CALCULATED
USING PSAPCA FIRE STATION NO. 12 WINDS
Hour
(PST)
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Average
Observed
Concentration
(ppm)
Kaiser
Bluff
0.02
0.00
0.00
0.00
0.00
MSG
MSG
0.00
0.00
0.00
0.01
0.00
0.00
0.01
0.02
0.00
0.00
0.01
0.01
0.01
0.01
0.00
0.01
0.01
0.006
Kaiser
Plant
0.04
0.11
0.02
0.15
0.10
0.10
0.01
0.15
MSG
MSG
0.07
0.15
0.11
0.06
0.04
0.11
0.08
0.07
0.07
0.07
0.05
0.05
0.04
0.04
0.077
ASARCO
Meeker
0.00
0.01
0.00
0.00
0.01
0.00
0.01
0.01
0.00
0.01
0.01
0.00
0.01
0.00
0.00
0.00
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.003
Calculated
Concentration
(ppm)
Kaiser
Bluff
0.01
0.02
0.00
0.10
0.04
0.01
0.01
0.01
0.03
0.06
0.06
0.06
0.06
0.02
0.08
0.00
0.01
0.01
0.13
0.09
0.00
0.11
0.14
0.04
0.048
Kaiser
Plant
0.00
0.01
0.00
0.09
0.01
0.01
0.01
0.26
0.07
0.00
0.00
0.20
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.028
ASARCO
Meeker
0.00
0.00
0.00
0.02
0.02
0.00
0.00
0.01
0.01
0.01
0.00
0.02
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.005
Ratio of Calculated
and Observed
Concentrations
Kaiser
Bluff
0.50
OO
OO
OO
MSG
MSG
OO
OO
OO
6.00
CO
CO
2.00
4.00
—
OO
1.00
13.00
9. .00
0.00
OO
14.00
4.00
8.00
Kaiser
Plant
0.00
0.09
0.00
0.60
0.10
0.10
1.00
1.73
MSG
MSG
0.00
1.33
0.09
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.36
ASARCO
Meeker
__
0.00
—
OO
2.00
—
0.00
1.00
00
1.00
0.00
OO
1.00
—
—
—
0.00
—
—
—
—
—
—
0.00
1.67
73
-------
24-hour average concentrations predicted at the Kaiser Plant site and the
ASARCO Meeker site are zero. If the Fire Station No. 12 winds are used in
the model calculations, the relatively high 24-hour average concentration
measured at the Kaiser Plant site is underpredicted by a factor of 2.78,
while the relatively low 24-hour average concentrations measured at the
Kaiser Bluff site and the ASARCO Meeker site are overpredicted by factors
of 8.00 and 1.67, respectively. Thus, neither set of wind inputs yields a
good correspondence between calculated and observed 24-hour average concen-
trations on 10 December 1982.
Table 3-19 compares the maximum observed and calculated 1-hour
and 3-hour average SO concentrations paired in space only on 10 December
1982. The calculated concentrations given in Table 3-19 for the Kaiser
Bluff and Plant sites are entirely determined by Kaiser emissions, while
the calculated concentrations given in the table for the ASARCO Meeker site
are entirely determined by St. Regis emissions. For both sets of SHORTZ
wind inputs, the calculated maximum 1-hour and 3-hour average concentrations
are within a factor of 2 of the observed concentrations at the ASARCO Meeker
site and are significantly higher than the observed concentrations at the
Kaiser Bluff site. If the Benny's winds are used in the model calculations,
no impact is predicted at the Kaiser Plant site. However, if the Fire
Station No. 12 winds are used in the model calculations, the maximum 1-hour
and 3-hour average concentrations calculated at the Kaiser Plant site are
within a factor of 2 of the maximum observed concentrations.
We conclude from the results of the SHORTZ calculations for 10
December 1981 that, during periods of moderate-to-strong south or south-
southwest winds at the ASARCO Benny's (N26th & Pearl) and the PSAPCA Fire
Station No. 12 sites, the wind directions at the two sites are not very
good indicators of the initial transport wind directions for the low-level
emissions from the Kaiser plant. With both sets of wind inputs, the
relatively low 1-hour, 3-hour and 24-hour average SO- concentrations
measured at the Kaiser Bluff site are overpredicted, the same result as
74
-------
TABLE 3-19
COMPARISON OF MAXIMUM OBSERVED AND CALCULATED 1-HOUR AND 3-HOUR
AVERAGE SO CONCENTRATIONS UNPAIRED IN TIME ON 10 DECEMBER 1981
Site
Observed
Concentration
(ppm)
Calculated
Concentration
(ppm)
Benny' s
Winds
Fire Station
No. 12 Winds
Ratio of Calculated
and Observed
Concentrations
Benny1 s
Winds
Fire Station
No. 12 Winds
(a) 1-Hour Average Concentrations
i
Kaiser Bluff
Kaiser Plant
ASARCO Meeker
0.02
0.15
0.02
0.13
0.00
0.01
0.14
0.26
0.02
6.50
0.00
0.50
7.00
1.73
1.00
(b) 3-Hour Average Concentrations
Kaiser Bluff
Kaiser Plant
ASARCO Meeker
0.01
0.11
<0.01
0.10
0.00
<0.01
0.10
0.11
0.01
10.00
0.00
-1.00
10.00
1,00
>1.00
75
-------
obtained above for the 30 March 1981 case using Benny's winds. The best
correspondence between the maximum observed and calculated 1-hour and
3-hour average concentraitons unpaired in time at the Kaiser Plant site is
obtained using the Fire Station No. 12 winds. However, both sets of wind
inputs yield equivalent results at the Kaiser Bluff site and the ASARCO
Meeker site if maximum observed and calculated 1-hour and 3-hour average
concentrations unpaired in time are compared. One of the possible
explanations for the results summarized in Tables 3-17 through 3-19 is that
the low-level winds in the vicinity of the Kaiser plant are channeled by
the terrain toward the northwest during periods of moderate-to-strong
south-southwest winds at Benny's and Fire Station No. 12. It is also
important to recognize that the Kaiser Plant site monitor is on Kaiser
property only about 200 meters north of the dry scrubber stacks for the
existing Line 4. As discussed in Section 2, these stack emissions present
a challenging modeling problem due to the uncertainties about the
appropriate enhancement in buoyant plume rise for 72 stacks in close
proximity and the uncertainties about the effects of aerodynamic building
wakes on plume rise and initial dispersion. Thus, another possible
explanation for the tendency to underpredict concentrations at the Kaiser
Plant site is that the current modeling approach for the Kaiser Plant
overestimates the buoyant rise of the dry scrubber stack emissions, at
least during periods of moderate-to-strong winds.
The 12 through 17 January 1981 Air Stagnation Episode
To assist in the discussion of this and the three other air stagnation
episodes during 1981, Figure 3-15 shows the locations of the PSAPCA and
ASARCO wind and SO air quality monitoring sites in the Tacoma area. (Figure
3-15 was provided to the H. E. Cramer Company by PSAPCA.) The three-letter
abbreviations used to define the locations of the various sites are identified
by site operator and name in Table 3-20. Although the PSAPCA hourly wind
76
-------
3255.0
5250.0 --
3245.0 -•
5240.0 - -
5235.0 -•
5230.0 - •
5225.0
330.0
535U)
540.0
545LO
550.0
555.0
Figure 3-15.
Locations of the PSAPCA and ASARCO wind and SO air quality
monitoring sites. (Only winds are measured at the ASARCO
sites indicated by the G> symbol.) The Universal
Transverse Mercator (UTM) X and Y coordinates in kilometers
are shown respectively at the bottom and the left-hand side
of the figure.
77
-------
TABLE 3-20
ABBREVIATIONS USED IN FIGURE 3-15 TO IDENTIFY PSAPCA AND ASARCO
WIND AND SO AIR QUALITY MONITORING SITES
Abbreviation
RTN
RES
BEN
UPL
HIL
MKR
FDW
VHN
GHR
THS
TAV
TWR
PRL
VST
FED
MAU
Monitoring Site
Operator
ASARCO
PSAPCA
Name
Ruston
Reservoir
Benny' s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
Tank House
Tavern (Wind Only)
Tower (Wind Only)
• N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
78
-------
and SO concentration measurements for all of 1981 were provided to the
H. E. Cramer company on computer tape, no ASARCO air quality data were
available to us on tape. For each day of each air stagnation episode, we
extracted from the hard copy listings submitted by ASARCO to PSAPCA the
ASARCO 30-minute average wind and S00 concentration measurements. We then
converted the ASARCO 30-minute average parameters to hourly averages for
consistency with the PSAPCA data.
The 12 through 17 January 1981 air stagnation episode was character-
ized by shallow mixing depths and light winds. The 0700 PST sounding taken
at Portage Bay on 12 January showed a surface-based inversion approximately
800 meters in depth. Similar inversions were measured at 0700 on the mornings
of 13, 14 and 15 January, with the inversion depths ranging from about 600
to 650 meters. The surface-based inversion on the morning of 16 January
was only about 200 meters deep, but was very strong (a vertical potential
temperature gradient of about 0.055 degrees Kelvin per meter). A 200-meter
surface-based inversion was also measured at 0700 PST on 17 January, but
the strength of this inversion was only about half that of 16 January, If
the maximum afternoon temperature at the Kaiser plant is used with the
Holzworth (1972) technique to estimate the maximum afternoon (convective)
mixing depth, the maximum depth never exceeded 200 meters during the 6-day
period. The mechanical components of the mixing depth calculated using the
techniques of Benkley and Schulman (1979) suggest that the mixing depths
probably were in the range of 100 to 200 meters.
The wind speeds throughout the 12 through 17 January 1981 air
stagnation episode were so light that the PSAPCA vector mean wind directions
usually were reported as variable, The ASARCO wind directions on the Tacoma
peninsula (the Tower, Benny's and Reservoir sites) were highly variable and
almost random throughout the 6-day period. However, except for several
hours of winds from the south clockwise through north, the ASARCO Meeker
winds were from the northeast through southeast.
79
-------
The ASARCO smelter reported zero SO emissions from its Main
Stack on 11 January 1981, the day preceding the air stagnation episode.
The 15-minute average Main Stack SO- emission rates reported by ASARCO were
zero during the 6-day episode with the following exceptions:
• Emissions of 781 to 3,326 grams per second during the
period 1000 through 1500 PST on 12 January
• Emissions of 126 to 1,159 grams per second during the
period 1000 through 2400 PST on 13 January
• Emissions of 101 to 1,109 grams per second during the
first 12 hours of 14 January and less than or equal to
25 grams per second during the last 12 hours
• Emissions less than or equal to 25 grams per second
throughout 15 January
• Emissions less than or equal to 50 grams per second
prior to 1430 PST on 16 January, followed by emissions
of 580 to 2,495 grams per second throughout the re-
mainder of the day
• Emissions of 1,613 to 5,216 grams per second throughout
17 January
According to information provided by EPA Region 10 (Wilson, 1982b) , Pennwalt
burned natural gas during this air stagnation episode and Kaiser emissions
were about 91 percent of the 1981 annual average emissions.
80
-------
Table 3-21 summarizes the 24-hour average S09 concentrations
measured during the 12 through 17 January 1981 air stagnation episode.
During the first five days when ASARCO emissions were significantly cur-
tailed, the maximum observed concentrations were measured at the Kaiser
Bluff or ASARCO Meeker sites. Although the winds were too light to define
unambiguous source-receptor relationships, the combination of: (1) minimal
ASARCO emissions, and (2) the close proximity of the tideflats sources to
the Meeker and Bluff sites suggests that the observed concentrations at
these sites are primarily attributable to emissions from the tideflats
sources. After the ASARCO smelter resumed continuous operation on 17
January, the highest observed 24-hour average concentration shifted to the
ASARCO Ruston monitor; this concentration probably reflects the effects of
low-level fugitive emissions from the smelter.
We selected 16 January 1981 to test SHORTZ because the S07 concen-
trations measured at the Kaiser Bluff and ASARCO Meeker sites were probably
caused by emissions from the tideflats sources and because two of the 13
hourly S0« concentrations greater than or equal to 0.15 ppm at the Kaiser
Bluff site occurred on this day. We assumed zero SO emissions from Pennwalt
because of the use of natural gas and zero SO emissions from ASARCO, although
we recognize that the ASARCO emissions during the afternoon of 16 January
may have affected the observed concentrations. Based on the monthly average
emission rates provided by PSAPCA (Anderson, 1982), we increased the annual
average S09 emissions from U. S. Oil & Refining by 28 percent. We used
both ASARCO Benny's (N26th & Pearl) and Meeker wind directions and wind
speeds in the SHORTZ calculations. If the hourly average Benny's wind
speed was less than 1 meter per second, we set the wind speed equal to 1
meter per second. Because the Meeker wind speeds were consistently higher
than the Benny's wind speeds, we assumed the wind speed to be independent
of height below the elevation of the Benny's wind sensor in both sets of
SHORTZ calculations. The vertical potential temperature gradient for all
hours was set equal to 0.040 degrees Kelvin per meter, the average of the
0700 PST Portage Bay potential temperature gradients on 16 and 17 January.
81
-------
TABLE 3-21
24-HOUR AVERAGE SO CONCENTRATIONS DURING THE AIR STAGNATION
EPISODE OF 12 THROUGH 17 JANUARY 1981
Monitoring Site
ASARCO
Ruston
Reservoir
Benny' s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
PSAPCA
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Kaiser
Bluff
Plant
SO Concentration (ppm)
12 Jan
0.017
0.015
0.006
0.007
0.012
MSG
MSG
0.020
0.018
0.004
0.002
MSG
0.030
0.048
MSG
13 Jan
0.018
0.019
0.017
MSG
0.014
0.015
MSG
0.009
0.020
MSG
0.004
MSG
0.014
0.040
MSG
1.4 Jan
0.010
0.007
0.012
MSG
0.012
0.038
MSG
MSG
0.019
MSG
0.003
MSG
0.007
0.021
MSG
15 Jan
0.017
0.011
0.014
MSG
0.016
0.047
MSG
MSG
0.018
MSG
0.008
MSG
0.014
0.069
MSG
16 Jan
0.014
0.011
0.010
MSG
0.017
0.060
0.021
0.004
0.017
0.008
0.011
MSG
0.010
0.064
MSG
17 Jan
0.037
0.019
0.015
MSG
0.021
0.011
0.005
0.004
0.018
0.015
0.025
MSG
0.004
0.031
MSG
82
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The mechanical component of the mixing depth was assumed to be 185 meters
based on the 24-hour average wind speed at the Meeker site and the Benkley
and Schulman (1979) relationship (see Equation 3-1). Following the Turner
(1964) approach, the Pasquill D stability category existed at McChord Air
Force Base during 17 hours of 16 January, the stable E category existed
during 4 hours, the slightly unstable C category existed during 2 hours
and there was a single hour with the unstable B category.
The observed hourly and 24-hour average SO. concentrations at the
Kaiser Bluff and ASARCO Meeker sites on 16 January 1981 are compared with
the concentrations calculated by SHORTZ using Benny's and Meeker winds in
Tables 3-22 and 3-23, respectively. If the Benny's winds are used in the
model calculations, SHORTZ closely matches the observed 24-hour average
concentration at the Bluff site, but predicts no impact at the Meeker site.
If the Meeker winds are used in the model calculations, SHORTZ underestimates
the observed 24-hour average concentrations at both sites by a factor of
about 5. As expected, the hour-to-hour correspondence between observed and
calculated concentrations is poor. However, for both sets of wind inputs,
Table 2-34 shows that the observed and calculated maximum 1-hour and 3-hour
average concentrations paired in space only at the Bluff site are within
the approximate factor of 2 accuracy generally attributed to the results of
short-term dispersion model calculations in the absence of complicating
factors (AMS, 1978).
We conclude from the results presented in Tables 3-22 through
3-24 that emissions from the tideflats sources probably follow curvilinear
trajectories under stable, light wind conditions. The results of the SHORTZ
calculations suggest that the ASARCO Benny's (N26th & Pearl) winds provide
the best representation of the transport of emissions from the tideflats
sources to the Kaiser Bluff site under stable, light wind conditions.
These emissions then appear to be diverted toward the northwest by the
elevated terrain, resulting in relatively high concentrations at the Meeker
site. Because SHORTZ cannot account for this change in trajectory, SHORTZ
cannot account for the observed concentrations at the Meeker site.
83
-------
TABLE 3-22
COMPARISON OF THE OBSERVED HOURLY SO CONCENTRATIONS ON 16 JANUARY
1981 WITH THE CONCENTRATIONS CALCULATED USING ASARCO
BENNY'S (N26TH & PEARL) WINDS
Hour
(PST)
0100
0200
0300
0400
0500
! 0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Average
Observed
Concentration
(ppm)
Kaiser
Bluff
0.07
0.09
0.02
0.16
0.09
0.15
MSG
MSG
MSG
0.05
0.08
0.09
0.05
0.07
0.07
0.05
0.06
0.04
0.04
0.04
0.06
0.04
0.04
0.03
0.064
ASARCO
Meeker
Calculated
Concentration
(ppm)
Kaiser
Bluff
0.14 1 0.02
0.16
0.13
0.17
0.15
0.12
0.10
0.09
0.06
0.06
0.04
0.04
0.04
MSG
0.02
0.02
0.01
0.02
0.01
0.01
0.02
0.02
0.02
0.02
0.060
0.24
0.00
0.02
0.00
0.00
0.53
0.22
0.01
0.07
0.05
0.04
0.01
0.00
0.00
0.03
0.03
0.00
0.00
0.02
0.00
0.00
0.00
0.00
0.053
ASARCO
Meeker
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Ratio of Calculated
and Observed
Concentrations
Kaiser
Bluff
0.29
2.67
0.00
0.13
0.00
0.00
MSG
MSG
MSG
1.40
0.63
0.44
0.20
0.00
0.00
0.60
0.50
0.00
0.00
0.50
0.00
0.00
0.00
0.00
0.83
ASARCO
Meeker
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
MSG
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
84
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TABLE 3-23
COMPARISON OF THE OBSERVED HOURLY SO CONCENTRATIONS ON 16 JANUARY
1981 WITH THE CONCENTRATIONS CALCULATED USING
ASARCO MEEKER WINDS
Hour
0100
0200
0300
0400
0500
0600
0700
0800
0900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
Average
Observed
Concentration
(ppm)
Kaiser
Bluff
0.07
0.09
0.02
0.16
0.09
0.15
MSG
MSG
MSG
0.05
0.08
0.09
0.05
0.07
0.07
0.05
0.06
0.04
0.04
0.04
0.06
0.04
0.04
0.03
0.064
ASARCO
Meeker
0.14
0.16
0.13
0.17
0.15
0.12
0.10
0.09
0.06
0.06
0.04
0.04
0.04
MSG
0.02
0.02
0.01
0.02
0.01
0.01
0.02
0.02
0.02
0.02
0.060
Calculated
Concentration
(ppm)
Kaiser
Bluff
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.02
0.05
0.00
0.21
0.00
0.05
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.014
ASARCO
Meeker
0.04
0.04
0.03
0.04
0.00
0.03
0.04
0.00
0.00
0.00
0.01
0.02
0.00
0.00
0.00
0.00
0.04
0.04
0.00
0.00
0.00
0.00
0.00
0.00
0.014
Ratio of Calculated
and Observed
Concentrations
Kaiser
Bluff
0.00
0.00
0.00
0.00
0.00
0.00
MSG
MSG
MSG
0.00
0.25
0.56
0.00
3.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.22
ASARCO
Meeker
0.29
0.25
0.23
0.24
0.00
0.25
0.40
0.00
0.00
0.00
0.25
0.50
0.00
MSG
0.00
0.00
4.00
2.00
0.00
0.00
0.00
0.00
0.00
0.00
0.23
85
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TABLE 3-24
COMPARISON OF MAXIMUM OBSERVED AND CALCULATED 1-HOUR AND 3-HOUR AVERAGE
SO CONCENTRATIONS UNPAIRED IN TIME ON 16 JANUARY 1981
Site
Observed
Concentration
(ppm)
Calculated
Concentration
(ppm)
Benny' s
Winds
Meeker
Winds
Ratio of Calculated
and Observed
Concentrations
Benny ' s
Winds
Meeker
Winds
(a) 1-Hour Average Concentrations
Kaiser Bluff
ASARCO Meeker
0.16
0.17
0.53 (0.24)*
0.00
0.21
0.04
3.31 (1.50)*
0.00
1.31
0.24
(b) 3-Hour Average Concentrations
Kaiser Bluff
ASARCO Meeker
0.13
0.15
0.25 (0.09)*
0.00
0.09
0.04
1.92 (0.69)*
0.00
0.69
0.27
The numbers enclosed by parentheses consider only the 21 hours with
concentration measurements at the Kaiser Bluff site.
86
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The 14 through 20 October 1981 Air Stagnation Episode
The 14 through 20 October 1981 air stagnation episode was charac-
terized by light winds and shallow to relatively deep surface mixing
layers. The 0600 PST upper-air soundings taken at Portage Bay on 14 and 15
October both show mixing depths of about 150 meters with an adiabatic or
moist-adiabatic vertical potential temperature gradient within the surface
mixing layer. The 0600 PST Portage Bay soundings for 16 and 17 October
show early morning mixing depths of 300 to 400 meters with an adiabatic
lapse rate within the surface mixing layer. No Portage Bay sounding was
made on the morning of 18 October. The 0600 PST Portage Bay soundings on
the mornings of 19 and 20 October indicate early morning mixing depths
between 600 and 1,000 meters with a moist-adiabatic vertical potential
temperature gradient.
The ASARCO reports of stack SO emissions, which were provided by
PSAPCA (Anderson, 1982), indicate that there were no SO emissions from the
ASARCO Main Stack during most of the period 14 through 20 October 1981.
The exceptions are:
• Emissions of 655 to 8,215 grams per second during the
period 0315 through 0715 PST on 14 October
• Emissions of 277 to 1,336 grams per second on 15 October
• Emissions of 252 to 832 grams per second prior to 1330
PST on 16 October
However, according to PSAPCA (Carson, 1982), ASARCO was in operation on 20
October 1981 in spite of the fact that the in-stack SO monitor showed zero
emissions. Although PSAPCA believes that ASARCO curtailment reports can be
used to estimate emissions during periods when ASARCO is in operation and
the in-stack monitor shows zero emissions, time constraints for the
completion of this study precluded the use of emissions estimated from the
curtailment reports.
87
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The winds were so light during the period 14 through 20 October
1981 that the majority of the PSAPCA vector mean wind directions were
recorded as variable. The scalar mean wind speeds at the ASARCO Benny's
(N26th & Pearl) site were so light that the scalar wind directions may also
be unreliable. For the hours during the period 14 through 20 October with
Benny's wind speeds above 1 meter per second, the wind directions were from
the northwest through east, while the ASARCO Meeker wind directions tended
to be from the north through east-southeast. These winds suggest that:
(1) The curtailed ASARCO stack and fugitive emissions may have affected SO
air quality on the Tacoma peninsula as well as at the Kaiser Bluff and
Plant sites; and, (2) Emissions from some of the tideflats sources such as
the St. Regis mill may have briefly affected SO air quality at the Kaiser
Bluff and Plant sites, but not at the ASARCO Meeker site.
Table 3-25 lists the observed 24-hour average SO- concentrations
for each day during the period 14 through 20 October 1981. As expected on
the basis of the ASARCO Benny's (N26th & Pearl) winds, negligible concentra-
tions were measured at the monitoring sites north of ASARCO and the tideflats
sources (Meeker, Vashon Island and Maury Island). After the reported complete
curtailment of ASARCO emissions on 17 October, the 24-hour average concentra-
tions at all sites tended to decrease. This result is probably explained
by a combination of the near-zero ASARCO emissions and the absence of wind
directions required for the direct transport of emissions from the tideflats
sources to the air quality monitoring sites.
The 23 through 25 October 1981 Air Stagnation Episode
The 0600 PST upper-air soundings taken at Portage Bay on 23 and
24 October 1981 show mixing depths of about 150 meters with a slightly
stable lapse rate within the surface mixing layer. (No sounding was made
on 25 October.) Based on the maximum afternoon ambient air temperatures at
the Kaiser Plant and the light wind speeds, relatively shallow mixing depths
should have persisted throughout both days. According to PSAPCA (Anderson,
1982), ASARCO reported zero stack emissions beginning at 1315 PST on 16
October and continuing through 25 October. The wind speeds were so light
that the PSAPCA vector mean hourly wind directions generally were recorded
-------
TABLE 3-25
24-HOUR AVERAGE SO CONCENTRATIONS DURING THE AIR STAGNATION
EPISODE OF 14 THROUGH 20 OCTOBER 1980
Monitoring
Site
ASARCO
Ruston
Reservoir
Benny1 s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
PSAPCA
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Kaiser
Bluff
Plant
S0? Concentration (ppm)
14 Oct
0.014
0.013
MSG
MSG
MSG
0.011
0.009
0.002
MSG
0.013
0.011
0.004
0.007
0.017
0.020
15 Oct
0.010
MSG
MSG
MSG
MSG
MSG
0.018
0.003
MSG
0.007
0.014
0.003
0.004
0.016
0.017
16 Oct
MSG
MSG
MSG
MSG
MSG
0.000
0.016
0.001
MSG
0.018
0.012
0.003
0.001
0.011
0.017
17 Oct
MSG
MSG
0.001
MSG
0.004
0.000
0.004
MSG
0.001
0.002
0.010
0.001
0.000
0.008
0.008
18 Oct
MSG
MSG
0.006
MSG
0.010
0.000
0.003
0.000
0.000
0.008
0.008
0.005
0.000
0.008
0.008
19 Oct
MSG
MSG
0.003
MSG
0.004
0.000
0.007
0.000
0.000
0.005
0.003
0.002
0.000
0.006
0.008
20 Oct
MSG
0.004
0.005
0.009
0.006
MSG
MSG
0.000 1
0.001
0.004
0.017
0.006
0.002
0.006
0.012
89
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as variable. During the hours on 23 October with scalar mean wind speeds
above 1 meter per second, the ASARCO Benny's (N26th & Pearl) winds tended
to be from the northwest through northeast, while the ASARCO Meeker winds
tended to be from the northwest through the southeast. In general, the
Benny's winds were from the west through the northwest on 24 October and
the Meeker winds were highly variable. A general southerly flow was indi-
cated by the Benny's and Meeker winds on 25 October.
Table 3-26 lists the 24-hour average SO concentrations measured
during the period 23 through 25 October 1981. Although no stack SO emissions
were reported for the ASARCO smelter, the smelter was in operation (Carson,
1982), and the highest hourly SO concentrations on 23 October at the
Ruston, Reservoir, Benny's (N26th & Pearl), University Place and Highlands
sites occurred during hours when the Benny's wind directions suggest that
ASARCO was the most probable source of the SO.. On the other hand, the
highest hourly concentrations at these sites on 24 October occurred during
hours with light westerly winds at Benny's. Because of the circumstantial
evidence that ASARCO emissions directly affected the observed concentrations
on 23 October 1981, it would be of considerable interest to determine what
stack and fugitive emissions can occur when the in-stack S0_ monitor
indicates zero emissions.
One of the meteorological regimes identified in our previous
study of the Tacoma area (Cramer, et^ aJ., 1976) as being conducive to the
occurrence of relatively high short-term SO concentrations was termed "air
stagnation fumigation." When a stack plume is contained in an elevated
stable layer above the top of the surface mixing layer, the plume remains
aloft and does not mix to the ground until the top of the surface mixing
layer reaches the height of the plume. At this time, the plume is rapidly
mixed to the surface in a process called fumigation, resulting in relatively
high ground-level concentrations that rarely persist for longer than 1 or 2
hours. Prior to fumigation, the angular width of the plume may be very
narrow or very large, depending on the variability of the winds at plume
height. We previously concluded from the simultaneous occurrence at many
90
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TABLE 3-26
24-HOUR AVERAGE SO CONCENTRATIONS DURING THE AIR STAGNATION
EPISODE OF 23 THROUGH 25 OCTOBER 1981
Monitoring
Site
ASARCO
Ruston
Reservoir
Benny' s
University Place
Highlands
Meeker
Federal Way
Vashon island
Gig Harbor
PSAPCA
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Kaiser
Bluff
Plant
S0? Concentration (ppm)
23 Oct
0.027
0.027
0.020
0.020
0.022
0.019
0.012
0.001
0.005
0.018
0.015
0.010
0.010
MSG
0.021
24 Oct
0.030
0.037
0.044
0.026
0.055
0.039
0.016
0.006
0.020
0.050
0.030
0.016
0.027
MSG
0.028
25 Oct
0.004
0.002
0.001
0.007
0.004
0.024
0.011
0.002
0.000
0.006
0.008
0.007
0.011
MSG
0.015
91
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or all of the monitoring sites in the Tacoma area of relatively high short-
term SO concentrations that the ASARCO plume is spread over a sector as
large as 360 degrees prior to fumigation. Although we found in our 1976
study cases in which the emissions appeared to have been confined within
sectors smaller than 360 degrees, the air stagnation fumigation calcu-
lations described in our 1976 report were restricted to the apparent
360-degree sector cases because we did not have any objective basis for
specifying smaller sectors.
The Cramer, _e_t_ al. (1976) air stagnation fumigation model is
implemented by LONGZ under the following assumptions:
• Plume rise is determined by the stable meteorological
conditions prior to fumigation
• The wind-direction distribution in the stable layer is
circular (i.e., pollutants in the stable layer are
spread about the stack in a circular pattern)
• When the mixing depth reaches the plume stabilization
height, the pollutants are rapidly mixed to the ground
(the rate of vertical mixing is determined by the ver-
tical turbulent intensity in the unstable surface layer)
As discussed in Section 4 of this report, the air stagnation fumigation
model as used by Cramer, et_ jil_. (1976) tended to underestimate the observed
3-hour average SO concentrations by an average of 30 to 40 percent, pro-
bably because the wind-direction distribution at the height of the ASARCO
plume was not circular. However, the sample size was too small to confirm
statistically that there was a bias toward underestimation.
During the period 1400 through 1600 PST ON 24 October 1981,
relatively high SO concentrations were measured throughout the Tacoma
area. We therefore applied LONGZ in its fumigation mode to this period.
92
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We included in the model calculations all of the existing sources discussed
in Section 2 except the ASARCO Main Stack, which we assumed to have zero
emissions based on the emission rates reported by ASARCO to PSAPCA. We
multiplied the 1981 average SCL emission rates for the Pennwalt sources
by 0.90 and the 1981 average emission rates for the U. S. Oil & Refining
Sources by 1.28 to adjust to the monthly average emissions provided by
PSAPCA (Anderson, 1982). The mixing depth of 150 meters and the vertical
potential temperature gradient of 0.003 degrees Kelvin per meter estimated
from the 0600 PST Portage Bay sounding were assumed in the fumigation
calculations. The 3-hour average wind speed at Benny's of 1.2 meters per
second was assumed to be representative for all elevations below the
elevation of the Benny's wind sensor. Following the Turner (1964)
criteria, there were 2 hours of B stability and 1 hour of C stability at
McChord Air Force Base during the period 1400 through 1600 PST PST. We
used the LONGZ (and SHORTZ) default vertical turbulent intensity for B
stability of 0.108 and the McChord 3-hour average surface temperature of
296 degrees Kelvin in the air stagnation fumigation calculations.
Table 3-27 compares the observed and calculated 3-hour average
SO concentrations for the period 1400 through 1600 PST on 24 October
1981. The only monitor at which the correspondence between observed and
calculated concentrations is what we would expect on the basis of our
previous experience with the air stagnation fumigation model is the Kaiser
Plant site (no data are available for the Kaiser Bluff site). The model
underpredicts the observed concentrations on the Tacoma peninsula by an
order of magnitude or more except at the Ruston monitor which is signi-
ficantly impacted by the assumed ASARCO fugitive emissions. Comparison of
Tables 3-26 and 3-27 shows that the calculated 3-hour average concentrations
are also below the observed 24-hour average concentrations at all sites
except the Kaiser Plant site. We are therefore unable to reconcile the
observed S0« concentrations on 24 October 1981 with the reported SO
emissions, and we recommend that the actual emissions during the episode be
further investigated. The good model performance within the tideflats and
the very poor model performance on the Tacoma peninsula provide circum-
93
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TABLE 3-27
COMPARISON OF OBSERVED AND CALCULATED 3-HOUR AVERAGE S0r
CONCENTRATIONS FOR THE PERIOD 1400 THROUGH 1600 ^
PST on 24 OCTOBER 1981
Monitoring
Site
ASARCO
Ruston
Reservoir
Benny' s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
PSAPCA
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Kaiser
Bluff
Plant
SO concentration (ppm)
Observed
0.057
0.103
0.197
0.060
0.256
0.040
0.020
0.010
0.080
0.183
0.123
0.010
0.013
MSG
0.049
Calculated*
0.026
0.011
0.009
0.005
0.007
0.009
0.003
0.004
0.006
0.010
0.012
0.005
0.006
0.025
0.040
Ratio of Calculated
and Observed
Concentrations
0.46
0.11
0.05
0.08
0.03
0.23
0.15
0.40
0.08
0.05
0.10
0.50
0.46
MSG
0.82
LONGZ was used in the form required to implement the Cramer, et al. (1976)
air stagnation fumigation model.
94
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stantial evidence that ASARCO's fugitive emissions may have been higher
than assumed in the model calculations and/or that there may have been
SO emissions from the ASARCO Main Stack.
The 9 through 10 November 1981 Air Stagnation Episode
No upper-air sounding is available for the morning of 9 November
1981 because the DOE specialist who takes the soundings was unable to return
to the Seattle-Tacoma airport, which was closed by fog. However, the 0700
PST Portage Bay sounding on 10 November shows a relatively strong surface-
based inversion (vertical potential temperature gradient of about 0.03
degrees Kelvin per meter) with a depth of about 400 meters. The 15-minute
average ASARCO Main Stack SO emission rates reported to PSAPCA varied from
1,210 to 3,730 grams per second prior to 0930 PST on 9 November. No ASARCO
stack SO. emissions were reported until 0345 PST on 10 November; the 15-
minute average emission rates varied from 25 to 11,012 grams per second
throughout the remainder of 10 November.
The wind speeds on 9 November 1981 were so light that the majority
of the PSAPCA hourly vector mean wind directions were recorded as variable.
The ASARCO Benny's (N26th & Pearl) winds were from the northeast through
east until about 1100 PST on 9 November when the winds shifted to the west.
Hourly SO concentrations above 0.10 ppm occurred at the N26th & Pearl,
Ruston and Reservoir sites during the period 1200 through 1400 PST. When
the Benny's winds shifted to the southeast between 1400 and 1500 PST, the
hourly concentrations at the sites on the Tacoma peninsula decreased and
hourly concentrations above 0.10 ppm were measured at the Gig Harbor site.
One possible explanation for these variations in SO concentrations is that
ASARCO fugitive and/or stack emissions were transported over the Narrows
(the body of water west of the Tacoma peninsula) during the early morning
hours of 9 November, were advected over the Tacoma peninsula following the
shift to west winds and were advected over the Gig Harbor area following
the shift to southeast winds. However, the wind speeds were so light and
95
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the wind directions so variable that this hypothesis is highly speculative.
In contrast to the hourly concentrations at the Gig Harbor, N26th & Pearl,
Ruston and Reservoir sites on 9 November, the hourly concentrations at the
Kaiser Bluff and Plant sites and the Meeker site were all below 0.10 ppm.
The wind speeds on 10 November 1981 were also so light that the
majority of the PSAPCA hourly vector mean wind directions were recorded as
variable. The scalar mean wind directions at the ASARCO Benny's (N26th &
Pearl) and Meeker sites were highly variable throughout the day, with con-
current wind directions differing by as much as 180 degrees. However,
there was a tendency for southeast winds at the Benny's and Meeker sites
during the last third of 10 November. With the exception of the Ruston
site at 0100 PST, no hourly concentration above 0.10 ppm was recorded in
the Tacoma area.
Table 3-28 gives the 24-hour average SO concentrations measured
on 9 and 10 November 1981. As discussed above, the highest 24-hour average
concentrations observed on 9 November, which were measured at the N26th &
Pearl, Benny's, N37th & Vassault and Gig Harbor sites, are attributable to
several relatively high hourly concentrations. Emissions from the ASARCO
smelter appear to be the most probable cause of the relatively high con-
centrations. The hourly and 24-hour average concentrations on 10 November
were lower and more uniform in space and time than on 9 November, a result
that is possibly explained by the highly variable wind directions.
96
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TABLE 3-28
24-HOUR AVERAGE SO CONCENTRATIONS DURING THE AIR STAGNATION
EPISODE OF 9 THROUGH 10 NOVEMBER 1981
Monitoring
Site
ASARCO
Ruston
Reservoir
Benny1 s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
PSAPCA
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Kaiser
Bluff
Plant
SO. Concentration (ppm)
9 Nov
MSG
0.047
0.067
0.019
0.040
0.040
0.009
0.003
0.043
0.058
0.055
0.005
0.023
0.031
0.037
10 Nov
MSG
0.004
0.013
0.019
0.009
0.026
0.016
0.005
0.008
0.009
0.012
0.010
0.013
0.017
0.028
97
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This page intentionally left blank.
98
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SECTION 4
STATISTICAL EVALUATION OF PREVIOUS APPLICATIONS OF
THE SHORTZ/LONGZ MODELS IN THE TACOMA AREA
Time and level-of-effort constraints prevented the completion of
the second subtask of this study, the evaluation of the performance of the
SHORTZ/LONGZ dispersion models following procedures based on the sugges-
tions contained in the August 1981 draft EPA report "Interim Procedures for
Evaluation of Air Quality Models." The only model testing performed as
part of the study described in this report consisted of the application of
SHORTZ and LONGZ (air stagnation fumigation mode) to selected short-term
periods when emissions from the tideflats sources appear to have affected
S00 ambient air quality at the Kaiser Bluff and Plant sites and the ASARCO
*-
Meeker site (see Section 3.3). The purpose of these case-study calculations
was to evaluate the general modeling approach under consideration for the
tideflats sources, including the selection of the most representative
meteorological inputs. (In the ideal situation, the model methodology
developed using a case-study approach with 1981 emissions, meteorological
and air quality data would then be evaluated using an independent data set
such as the 1980 emissions, meteorological and air quality data.) Although
it was not possible to evaluate SHORTZ or LONGZ as part of this study, it
is important to note that the two models were previously tested in the
Tacoma area as part of a study of the ASARCO smelter (Cramer, e_t^ aJ^. , 1976).
The results of the model calculations described in detail in Appendix E of
the Cramer, et al. (1976) report are used in the following paragraphs to
illustrate how we had hoped to be able to evaluate model performance in
this report.
The August 1981 draft EPA report "Interim Procedures for Evaluation
of Air Quality Models" suggests that the evaluation of a dispersion model
begin with an examination of the specific modeling problem to determine if
the current Guideline on Air Quality Models (EPA, 1978) recommends a reference
model for the intended type of application. If so, the reference model is
99
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used as a basis for comparison to determine if the proposed model is better
than, comparable to, or not as good as the reference model. In the absence
of a reference model, the interim procedures for model evaluation consist
of two steps: (1) a technical evaluation of the proposed model, and (2) a
performance evaluation of the proposed model.
When it is not possible to identify an appropriate reference
model, it is suggested in the August 1981 draft EPA report that the proposed
model be technically evaluated on its own merits in order to answer quali-
tatively the following questions:
1. Are the model formulations and internal constructs of
the model well founded in theory?
2. Does the theory fit the practical aspects and constraints
of the problem?
As noted in Section 1.1, EPA Region 10 considers the SHORTZ/LONGZ models to
be the most appropriate dispersion models available for application to the
Tacoma tideflats area, considering data base availability, source types and
the topographic setting. This opinion is based on the Region's review of
the technical documentation of the SHORTZ/LONGZ models (Bjorklund and Bowers,
1979) and the past performance of the models in the Region (Cramer, et al. ,
1976 and Bowers, £t_ _a_l. , 1980). Consequently, we believe that the answer
to each of the above questions is affirmative.
The August 1981 draft EPA report recommends that a model perform-
ance protocol be established before performing the model evaluation effort.
This protocol defines in advance of the model testing the model inputs and
other calculations procedures, the specific statistical measures to be used
in the model evaluation and the relative importance of the various measures
of performance. The Cramer, _et_ a_l. (1976) study compared observed and
calculated SO concentrations paired in space and time, the most rigorous
of the possible pairings. (Other possible comparisons of observed and cal-
100
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culated concentrations include concentrations paired in space only and in
time only.) SHORTZ was used by Cramer, e_t^ _al. (1976) to calculate hourly
SO concentration patterns for hours with the critical wind-speed and limited
mixing conditions when the ASARCO plume was simultaneously detected by two
or more air quality monitors so that the observations could be used to
estimate the effective transport wind direction to the nearest degree.
(The critical wind speed and limited mixing conditions are discussed in
Sections 3 and 5, respectively.) LONGZ, with the modified meteorological
inputs discussed in Section 4.3 of the Cramer, _et_ a.1^ (1976) report, was
used to calculate 3-hour average concentrations for periods when air
stagnation fumigation caused the occurrence of relatively high ground-level
concentrations at all monitoring sites in the Tacoma area. (A discussion of
air stagnation fumigation is given in Section 3.) Although the Cramer, et
al. (1976) study focused attention on the highest observed and calculated
concentrations, all of the observed and calculated concentrations are
presented in Appendix E of their report. We used these results to
calculate four measures of performance which are suggested in the August
1981 draft EPA report, but which were not used by Cramer, et_ _al. (1976),
The first of the four measures of performance is the bias (average
difference between observed and calculated concentrations) which is given
by
i = Xoi - Xci (4~2)
AX = the bias or average difference between observed and calculated
concentrations
N = the number of pairs of observed and calculated concentrations
used to compute AX
101
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= the i observed concentration
= the i calculated concentration
The second measure of performance is a measure of the noise in the results
2
of the model calculations and is provided by the variance a of the differ-
ences
, - AX)
(4-3)
The third measure of performance is a measure of the gross variability of
the differences and is given by the mean square error
MSE = -
(4-4)
1=1
The fourth measure of performance is the linear correlation coefficient
between observed and calculated concentrations, defined as
N
(xoi -
r =
r N
- 2
2
1=1
(4-5)
1/2
(x
ci
(Equation (4-5) is continued)
102
-------
* E
N
Y^
(x X} -
^ ^xoi xci
Xci
(4-5)
1/2
where x is the mean of the observed concentrations and x is the mean of
the calculated concentrations. The correlation coefficient r, which ranges
in absolute magnitude from 0 (no correlation between observed and calculated
concentrations) to 1.0 (perfect correlation), is a measure of the degree to
which the magnitude of the model predictions increases linearly with the
magnitude of the observations. However, the correlation coefficient is
insensitive to the rate of increase and is not a measure of absolute accuracy.
The SHORTZ performance statistics for the hours with the critical
wind-speed condition and the hours with the limited mixing condition are
given in Tables 4-1 and 4-2, respectively. The SHORTZ performance statistics
for the two sets of hours in combination are given in Table 4-3. The perform-
ance statistics for LONGZ as an air stagnation fumigation model are given
in Table 4-4. Because PSAPCA and ASARCO both have SO monitors at N26th
& Pearl (the separation is approximately 42 meters) , separate performance
statistics — based on the SO- concentrations measured by the two nearby
monitors — are listed in Tables 4-1 through 4-4. The 95 percent confidence
limits on the biases in Tables 4-1 through 4-4 were calculated using a one
sample Student's t test, the 95 percent confidence limits on the variances
2
and mean square errors were calculated using a x test and the 95 percent
confidence limits on the linear correlation coefficient were calculated
using the Fisher z transform (see Hoel, 1971).
103
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TABLE 4-1
SHORTZ PERFORMANCE STATISTICS FOR THE
CRITICAL WIND-SPEED CASES
Measure of
Performance
95 Percent Confidence Limits*
Average Observed
Concentration (ppm)
Number of Paired 1-Hour
Concentrations
Bias (ppm)
Variance (ppm )
2
Mean Square Error (ppm )
Linear Correlation
0.290 (0.413)
6 (7)
-4.67xlO~2 ± 4.69X10"1 (-1.43xlO~3 ± 4.02xlO~1)
6.47xlO~2 to 9.99X10"1 (6.73xlO~2 to 7.86xlO~1)
5.48xlO~2 to 8.46X10"1 (5.41xlO~2 to 8.36X10"1)
-0.444 to 0.930 (-0.428 to 0.913)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
nearby PSAPCA monitor.
104
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TABLE 4-2
SHORTZ PERFORMANCE STATISTICS FOR THE
LIMITED MIXING CASES
Measure of
Performance
95 Percent Confidence Limits*
Average Observed
Concentration (ppm)
Number of Paired 1-Hour
Concentrations
Bias (ppm)
2
Variance (ppm )
2
Mean Square Error (ppm )
Linear Correlation
0.187 (0.188)
71 (71)
-1.23xlO~2 ± 3.04xlO~2 (-1.04xlO~2 ± 2.89xlO~2)
1.20xlO~2 to 2.34xlO~2 (1.09xlO~2 to 2.12xlO~2)
1.16xlO~2 to 2.16xlO~2 (1.05xlO~2 to 1.96xlO~2)
0.684 to 0.867 (0.714 to 0.881)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO
nearby PSAPCA monitor.
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
105
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TABLE 4-3
SHORTZ PERFORMANCE STATISTICS FOR THE CRITICAL
WIND-SPEED AND LIMITED MIXING CASES
Measure of
Performance
95 Percent Confidence Limits*
Average Observed
Concentration (ppm)
Number of Paired 1-Hour
Concentrations
Bias (ppm)
Variance (ppm )
2
Mean Square Error (ppm )
Linear Correlation
0.196 (0.208)
77 (78)
-1.40xlO~2 ± 3.68xlO~2 (-9.62xlO~3 ± 3.66xlO~2)
1.89xlO~2 to 3.52xlO~2 (1.87xlO~2 to 3.48xlO~2)
1.86xlO~2 to 3.45xlO~2 (1.85xlO~2 to 3.45xlO~2)
0.557 to 0.798 (0.621 to 0.830)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
nearby PSAPCA monitor.
106
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TABLE 4-4
LONGZ PERFORMANCE STATISTICS FOR THE
AIR STAGNATION FUMIGATION CASES
Measure of
Performance
95 Percent Confidence Limits*
Average Observed
Concentration (ppm)
Number of Paired 1-Hour
Concentrations
Bias (ppm)
2
Variance (ppm )
2
Mean Square Error (ppm )
Linear Correlation
0.158 (0.160)
10 (10)
4.10xlO~2 ± 8.51xlO~2 (4.30xlO~2 ± 8.64xlO~2)
6.00xlO~3 to 4.25xlO~2 (6.21xlO~3 to 4.38xlO~2)
6.22xlO~3 to 4.38xlO~2 (6.47xlO~3 to 4.56xlO~2)
-0.746 to 0.499 (-0.718 to 0.543)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
nearby PSAPCA monitor.
107
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In the absence of a model performance evaluation protocol, the
relative importance of each of the measures of performance listed in Tables
4-1 through 4-4 is a matter of personal judgment. For example, we consider
absence of bias in the results of dispersion model calculations to be of
critical importance. For convenience, Table 4-5 gives the biases and 95
percent confidence limits, normalized by dividing by the corresponding
averages of the observed concentrations. Inspection of Table 4-5 shows
that the hypothesis that SHORTZ and LONGZ are unbiased cannot be rejected
at the 95 percent confidence level. The results also illustrate the sen-
sitivity of apparent model performance to uncertainties in air quality
measurements (see the differences in the biases obtained for the critical
wind-speed cases using the PSAPCA and ASARCO N26th & Pearl concentration
measurements). Another model attribute of concern is the variability of
the model's predictions. To illustrate the variability in the SHORTZ and
LONGZ concentration calculations, Table 4-6 gives the root mean square
(RMS) errors (square roots of the mean square errors) , normalized by
dividing by corresponding averages of the observed concentrations. The
typical RMS error is about 80 percent of the observed concentration, a
result that is consistent with the approximate factor of 2 accuracy
generally attributed to the results of short-term dispersion model
calculations (AMS, 1978).
108
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TABLE 4-5
BIASES AND 95 PERCENT CONFIDENCE LIMITS NORMALIZED BY
DIVIDING BY THE AVERAGE OBSERVED CONCENTRATIONS
Meteorological
Regime
Normalized Bias and 95%
Confidence Limits*
Critical Wind-Speed Condition
Limited Mixing Condition
Critical Wind-Speed and
Limited Mixing Conditions
Air Stagnation Fumigation
-0.16 ± 1.62 (0.00 ± 0.97)
-0.07 ± 0.16 (-0.06 ± 0.15)
-0.07 ± 0.19 (-0.05 ± 0.18)
0.26 ± 0.54 (0.27 ± 0.54)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
nearby PSAPCA monitor.
TABLE 4-6
ROOT MEAN SQUARE (RMS) ERRORS NORMALIZED BY DIVIDING
BY THE AVERAGE OBSERVED CONCENTRATIONS
Meteorological Regime
Normalized RMS Error*
Critical Wind-Speed Condition
Limited Mixing Condition
Critical Wind-Speed and
Limited Mixing Conditions
Air Stagnation Fumigation
1.29 (0.90)
0.68 (0.64)
0.82 (0.77)
0.73 (0.73)
The numbers enclosed by parentheses are based on the concentrations
measured by the ASARCO SO monitor at N26th & Pearl rather than by the
nearby PSAPCA monitor.
109
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110
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SECTION 5
PRELIMINARY SHORTZ/LONGZ DISPERSION MODEL METHODOLOGY
5.1 SHORTZ DISPERSION MODEL METHODOLOGY
Source Inputs
Our preliminary SHORTZ source inputs for the existing and proposed
SO sources in and adjacent to the Tacoma tideflats area are given in Section
2. Because these inputs were developed from information provided by EPA
Region 10 and PSAPCA, we suggest that they be reviewed by these agencies
before they are used in any SHORTZ calculations for regulatory purposes.
For example, the source inputs given in Section 2 for the proposed new SO
sources at the Kaiser Plant are based on the best information available
during the course of our study and are subject to change. Section 2 of
this report and Section 2.1.2 of the report by Bjorklund and Bowers (1982)
provide guidance on how to develop SHORTZ source inputs for new sources in
the tideflats area.
Receptor Inputs
The maximum SO air quality impacts of emissions from the existing
and proposed sources located in and adjacent to the Tacoma tideflats area
can be expected to occur within the area shown in Figure 1-1. The Universal
Transverse Mercator (UTM) X (east-west) coordinates of this area range from
537 to 552 kilometers, while the UTM Y (north-south) coordinates range from
5,230 to 5,242 kilometers. We believe that the minimum receptor spacing
required to detect the maximum short-term concentrations produced by
emissions from the individual and combined sources is 500 meters. Conse-
quently, our suggested receptor array covers the area shown in Figure 1-1
with receptors placed at 500-meter invertals in a Cartesian coordinate
system (UTM coordinates). These SHORTZ receptor inputs in meters, including
receptor elevations in meters above mean sea level (MSL), are contained in
111
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Appendix B. In addition to the regular receptor array in Appendix B, EPA
Region 10, PSAPCA and the Washington DOE may wish to place discrete receptors
at the locations of SO air quality monitors and other points of interest.
Table 5-1 gives the UTM coordinates and elevations of the SO air quality
monitors in and adjacent to the Tacoma tideflats area.
Meteorological Inputs
Table 5-2 lists the hourly meteorological inputs required by the
SHORTZ model. One of the major objectives of the study described in this
report was to determine the most representative wind inputs for use in the
SHORTZ calculations. Our review of the available wind and SO air quality
data (see Section 3) indicates that wind measurements made at a single
point in or adjacent to the tideflats area cannot be expected to be repre-
sentative of the winds affecting the transport and dispersion of emissions
from all of the existing and proposed sources under all meteorological
conditions. If wind data from a single site are selected for modeling
purposes as required by the SHORTZ/LONGZ models, we believe that—of the
wind data available for use in this study—the ASARCO Benny's (N26th &
Pearl) winds are most likely to be representative of the winds affecting
the transport and dispersion of emissions from all of the existing and
proposed SO sources under most meteorological conditions. We consider the
ASARCO Benny's scalar mean winds to be preferable for modeling purposes to
the PSAPCA N26th & Pearl vector mean winds for the reasons given in the
following paragraph. It is important to note that the SHORTZ/LONGZ models
assume that the wind speed below the reference level (above mean sea level)
is equal to the reference level wind speed. If the reference level is
defined as the height above mean sea level of the Benny's wind sensor, this
model assumption is supported by the wind-speed data from the PSAPCA Fire
Station No. 12, Willard School and N26th & Pearl sites (see Section 3.1).
The uncertainty in measured wind directions increases as the wind
speed decreases. For example, with calm winds (zero wind speeds) the
measured "wind direction" has no physical meaning and, in the absence of
112
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instrumentation problems, generally should correspond to the wind direction
from the last instantaneous wind observation with a wind speed above the
instrument threshold wind speed. According to PSAPCA (Carson, 1982),
PSAPCA hourly wind directions are vector averages only if the scalar
average wind speeds are greater than or equal to 1.5 knots (0.77 meters per
second). If the hourly scalar average wind speed is less than 1.5 knots,
PSAPCA records the wind direction as variable because of the uncertainties
in measured wind directions under light wind conditions. ASARCO, on the
other hand, computes scalar average wind speeds and wind directions for all
wind speeds, including very light wind speeds. As indicated in Section 3,
some of the highest concentrations measured in and adjacent to the Tacoma
tideflats area occur with hourly scalar average wind speeds below 1.5
knots. Thus, the ASARCO scalar wind directions provide the only available
information on wind directions during these periods. It has also been our
experience that scalar average wind speeds are more reliable for modeling
purposes than vector average wind speeds when the wind speed is below about
2 meters per second. For these reasons, we recommend the use of the ASARCO
Benny's (N26th & Pearl) winds in preference to the PSAPCA N26th & Pearl
winds.
We suggest that the majority of the SHORTZ hourly meteorological
inputs other than reference level wind direction and wind speed be assigned
on the basis of the Pasquill stability category defined using the Turner
(1964) scheme, which relates cloud cover and surface wind speed to stability.
Because of time constraints, we used McChord Air Force Base cloud-cover and
wind-speed observations to develop hourly meteorological inputs for use in
this study. However, we believe that it would be more appropriate to merge
the McChord Air Force Base cloud-cover observations with the concurrent
Benny's wind-speed observations to assign stability. The SHORTZ default
values for the wind-profile exponent and for the hourly vertical (o') and
lateral (a') turbulent intensities for rural areas are listed in Tables 5-3
A
and 5-4, respectively. We point out that our previous study of the Tacoma
area indicated that hours with F stability, as defined by Turner (1964),
should be redefined as E stability to account for the effects of surface
113
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TABLE 5-1
UNIVERSAL TRANSVERSE MERCATOR (UTM) COORDINATES AND ELEVATIONS
ABOVE MEAN SEA LEVEL (MSL) OF THE SO AIR QUALITY MONITORS
IN AND ADJACENT TO THE TACOMA TIDEFLATS AREA
Monitoring Site
Operator
ASARCO
PSAPCA
Kaiser
Name
Ruston
Reservoir
Benny' s
University Place
Highlands
Meeker
Federal Way
Vashon Island
Gig Harbor
N26th & Pearl
N37th & Vassault
Federal Way
Maury Island
Bluff
Plant
Coordinates
UTM X (m)
537,400
537,090
536,650
534,660
535,950
543,600
553,970
538,100
531,700
536,680
536,290
551,770
540,500
548,400
547,575
UTM Y (m)
5,237,360
5,235,670
5,235,120
5,229,660
5,233,500
5,238,750
5,247,780
5,249,300
5,239,440
5,235,150
5,236,380
5,241,750
5,244,000
5,235,410
5,234,190
Elevation
(m MSL)
76
131
122
117
110
104
130
104
104
123
109
143
119
125
3
114
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TABLE 5-2
HOURLY METEOROLOGICAL INPUTS REQUIRED
BY THE SHORTZ PROGRAM
Parameter
Definition
UR
DD
H
m
li
3z
Mean wind speed (m/sec) at height z
R
Mean wind direction (deg) at height z
Wind-profile exponent
R
Wind azimuth-angle standard deviation (rad) or
lateral turbulent intensity
Wind elevation-angle standard deviation(rad) or
vertical turbulent intensity
Ambient air temperature (°K)
Depth of surface mixing layer (m)
Vertical potential temperature gradient
115
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TABLE 5-3
SHORTZ AND LONGZ DEFAULT VALUES FOR
THE WIND-PROFILE EXPONENT
Pasquill
Stability
Category
A
B
C
D
E
F
Wind Speed (m/sec)
0.0 - 1.5
0.10
0.15
0.20
0.25
0.30*
0.40
1.6 - 3.1
0.10
0.10
0.15
0.20
0.25
0.30
3.2 - 5.1
0.10*
0.10
0.10
0.15
0.20
0.20*
5.2 - 8.2
0.10*
0.10*
0.10
0.10
0.15*
0.15*
8.3 - 10.8
0.10*
0.10*
0.10
0.10
0.10*
0.10*
>10.8
0.10*
0.10*
0.10
0.10
0.10*
0.10*
These combinations of wind-speed and Pasquill stability categories cannot
occur according to the Turner (1964) definitions of the Pasquill stability
categories.
TABLE 5-4
DEFAULT VALUES FOR HOURLY TURBULENT
INTENSITIES IN RURAL AREAS
Pasquill
Stability
Category
A
B
C
D
E
F
Vertical Intensity
a'E (rad)
0.1745
0.1080
0.0735
0.0465
0.0350
0.0235
Lateral Intensity
o-^ (rad)
0.2495
0.1544
0.1051
0.0665
0.0501
0.0336
116
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roughness elements and heat sources. Although we used McChord Air Force
Base ambient air temperatures in the SHORTZ calculations described in this
study, we believe that the temperatures from one of the two N26th & Pearl
sites or from Fire Station No. 12 probably are more suitable. In the absence
of any detailed climatology of thermal stratifications in the Tacoma area,
we recommend the vertical potential temperature gradients suggested by
Bjorklund and Bowers (1982) for use with SHORTZ in humid regions. These
potential temperature gradients are listed in Table 5-5. Because of time
constraints, we used the mixing depths estimated by Cramer, _et_ al_. (1976)
and listed in Table 5-6 to develop hourly meteorological inputs for selected
"worst-case" short-term periods. We believe that more appropriate mixing
depths for these periods could be derived from the Portage Bay upper-air
soundings and acoustic sounder measurements (see Section 3.1).
The Cramer, et_ a^. (1976) study identified three important mete-
orological regimes for emissions from the ASARCO Main Stack. Two of these
regimes, the critical wind-speed condition and fumigation,, are discussed in
Section 3. The third meteorological regime described by Cramer, et al,
(1976), which was defined as "limited mixing", consists of the combination
of light winds with the ASARCO plume contained within the surface mixing
layer, especially with neutral or slightly stable conditions within the
mixing layer. The limited mixing condition usually can be expected to
cause the highest 1-hour to 3-hour average concentrations calculated by
SHORTZ. Cramer, _et_ _al_. (1976) found fumigation to be the least important
of the three meteorological regimes. Although the study described in this
report focused attention on the sources within the tideflats, we have not
found any reasons to change the basic conclusions of the 1976 study.
However, we point out that we neglected the effects of ASARCO fugitive
emissions in our 1976 study because they were unquantified and only a small
fraction of the Main Stack emissions. The air quality measurements at the
ASARCO Ruston and PSAPCA N37th & Vassault sites, which were not in
existence in 1976, indicate that ASARCO fugitive emissions can cause
relatively high S0_ concentrations in the immediate vicinity of the
117
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TABLE 5-5
VERTICAL POTENTIAL TEMPERATURE GRADIENTS
SUGGESTED FOR HUMID REGIONS
Pasquill
Stability
Category
A
B
C
D
E
F
Wind Speed (m/sec)
0.0 - 1.5
0.000
0.000
0.000
0.015
0.030*
0.035
1.6 - 3.1
0.000
0.000
0.000
0.010
0.020
0.025
3.2 - 5.1
0.000*
0.000
0.000
0.005
0.015
0.015*
5.2 - 8.2
0.000*
0.000*
0.000
0.003
0.010*
0.010*
8.3 - 10.8
0.000*
0.000*
0.000
0.003
0.003*
0.003*
>10.8
0.000*
0.000*
0.000
0.003
0.003*
0.003*
These combinations of wind-speed and Pasquill stability categories cannot
occur according to the Turner (1964) definitions of the Pasquill stability
categories.
TABLE 5-6
MIXING DEPTHS IN METERS*
Pasquill
Stability
Category
A
B
C
D
E
Wind Speed (m/sec)
0.0 - 1.5
875
875
875
500
125
1.6 - 3.1
940
940
940
595
250
3.2 - 5.1
940
940
690
440
5.2 - 8.2
1000
875
8.3 - 10.8
1000
1000
>10.8
1000
1000
From Table 3-9 of Cramer, et al. (1976).
118
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smelter. With the possible exception of air stagnation episodes, we have
not found any firm evidence that ASARCO fugitive emissions have a
significant air quality impact at the distances of the other SO air
quality monitoring sites.
The important meteorological regimes for the ASARCO smelter are
also important meteorological regimes for the existing and proposed S0?
sources in the tideflats. To identify 24-hour critical wind-speed cases,
we used our persistence search (PRSIST) data analysis program with the
ASARCO Benny's (N26th & Pearl) wind data and concurrent McChord Air Force
Base Pasquill stability categories (Turner, 1964 method) to isolate all
periods when winds greater than or equal to 4 meters per second persisted
within any 25-degree sector for 20 or more hours and the stability categor-
ies were C, D or the combined E and F categories. Nine periods satisfied
these criteria. Because of the close proximity to elevated terrain of
sources such as St. Regis on the west wide of the tideflats and the pro-
posed Tacoma City Light plant on the east side of the tideflats, we examined
the same data set for persistent limited mixing cases with wind directions
toward elevated terrain. PRSIST identified five cases when winds less
than or equal to 4 meters per second persisted within a 25-degree sector
for 20 or more hours and there were no more than 5 hours with unstable
(A, B, and C categories) conditions. The 25-degree sector was required to
be in the range of 180 to 250 degrees or of 035 to 085 degrees, the wind
directions required to transport emissions from the tideflats sources toward
elevated terrain. Our criteria for the 3-hour critical wind-speed cases
were: (1) wind directions within a 2-degree sector, (2) neutral D stability
during all 3 hours, and (3) mean wind speeds greater than or equal to 4
meters per second. Thirteen 3-hour periods satisfied these criteria.
Finally, the criteria for our 3-hour limited mixing cases were: (1) wind
directions within a 3-degree sector, (2) stable (the combined E and F cate-
gories) conditions during all 3 hours, (3) wind speeds less than or equal
to 2.5 meters per second, and (4) the wind directions required to transport
emissions from the tideflats sources toward elevated terrain (winds in the
119
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sector 180 to 250 degrees or in the sector 035 to 085 degrees) . Ten 3-hour
periods satisfied these criteria. The SHORTZ hourly meteorological inputs
for the "worst-case" 3-hour and 24-hour periods, developed using the pro-
cedures discussed above, are listed in Appendix C. The "worst-case" 3-hour
periods also contain the "worst-case" 1-hour periods. We point out that
the minimum hourly scalar average wind speed during these cases is 1.3
meters per second, which is almost double the wind speed below which PSAPCA
records wind directions as variable.
Maximum 5-minute average SO concentrations may be estimated from
the maximum 1-hour centerline concentrations calculated by SHORTZ using the
t law of Osipov (1972)
concentration is given by
t law of Osipov (1972) and others. Specifically, the 5-minute centerline
l/5
Xc£{5 min} = j- xc£(60 min} = 1.64 xc£ (60 min} (5-1) -1)
It is important to recognize that the ratios of the maximum 5-minute average
to maximum hourly average SO. concentrations measured by PSAPCA generally
exceed the 1.64 ratio given by Equation (5-1). For example, the ratio of
the N26th & Pearl 5-minute average concentration ending at 1432 PST on 17
June 1980 (1.16 ppm) to the hourly average concentration ending at 1455 PST
on 17 June (0.44 ppm) is 2.64. We believe that this result is explained by
the fact that the location of the air quality monitor was approximately one
hourly lateral dispersion coefficient a off the centerline of the plume
from the ASARCO Main Stack. The hourly concentration one o off the plume
y
centerline is reduced by the factor
120
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exp
/ \2~
- --A
2 a
W
= exp
2-
~ "2 ( a )
V y/
= 0.61
(5-2)
Assuming that the N26th & Pearl site was on the centerline of the 5-minute
average plume during 5 minutes of the 60-minute period ending at 1455 PST,
the ratio of the maximum observed 5-minute and 60-minute average concentra-
tions is
1.64 x p{60 min}
_ = 0 Ap
0.61 Xc£{60 min}
(5-3)
Because our regular receptor grid with a 500-meter spacing will not necessarily
detect hourly centerline concentrations for a specific source, the SHORTZ
user may wish to place discrete receptors in polar coordinates along radials
extending from the source in the directions of downwind transport for the
hours used in the SHORTZ calculations.
Program Control Parameters
Section 3 of the report by Bjorklund and Bowers (1982) provides a
detailed discussion of how to execute the SHORTZ computer program. As an
example, Table 5-7 gives the SHORTZ program control parameters for a run
that will calculate the 1-hour, 3-hour and 24-hour average S02 concentrations
produced by emissions from the existing sources (Section 2) at the regular
receptors (Appendix B) and discrete receptors (Table 5-1) discussed above
for each of three 24-hour periods. Although parameters NHOURS and ISW(l)
enable SHORTZ to use 2-hour average, 3-hour average, etc. meteorological
inputs, we recommend that hourly inputs be used with SHORTZ. The parameter
121
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TABLE 5-7
SHORTZ PROGRAM CONTROL PARAMETERS FOR AN EXAMPLE PROBLEM
SHORTZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
NSOURC
NXPNTS
NYPNTS
NHOURS
NDAYS
NGROUP
NXWYPT
ISW(l)
ISW(2)
ISW(3)
ISW(4)
ISW(5)
ISW(6)
No. of Input Sources
No. of Cartesian East-West Receptor Locations
or Polar Radial Receptor Distances
No. of Cartesian North-South Receptor Locations or
Polar Azimuth Bearings
No. of Sets of Meteorological Inputs per Day
Number of Days or Cases
No. of Source Combinations in the Output
No. of Discrete Receptors
Averaging Time in Hours for the Meteorological
Inputs
Define as "1" if Concentrations at Base Rate ISW(l)
are to be Printed
No. of Hours in First Concentration Averaging Time
No. of Hours in Second Concentration Averaging Time
No. of Hours in Third Concentration Averaging Time
Program Control and Source Data are Not Printed ("0"),
only Program Control Data are Printed ("1"), Only
Source Data are Printed ("2") or Both Program Control
Source Data are Printed ("3")
33 (Optional)
31 (Optional)
25 (Optional)
24 (Recommended and Default Value)
3 (Optional)
7 (Optional)
15 (Optional)
1 (Recommended and Default Value)
1 (Optional)
3 (Optional)
24 (Optional)
0 (Optional)
3 (Optional)
-------
TABLE 5-7 (Continued)
SHORTZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
NJ
LO
ISW(7)
ISW(8)
ISW(9)
ISW(IO)
ISW(ll)
ISW(12)
ISW(13)
ISW(14)
ISW(15)
ISW(16)
ISW(17)
TK
ZR
HA
Define as "1" if Terrain Elevations Are Used
Define as "1" to List Meteorological Inputs
Define as "1" if Wind Speed a Function of Height AGL
Rather than Height MSL
Define Print Output Unit Other than Unit "6"
Define as "1" if Concentrations are to be Averaged
Over Days or Cases
Used Ony When Standard Source Input Format Not Used
Cartesian ("0") or Polar ("1") Coordinate Regular
Receptor Array
Cartesian ("0") or Polar ("1") Coordinate Discrete
Receptor Array
Cartesian ("0") or Polar ("1) Source Coordinates
Define as "0" for Same Turbulent Intensities for
All Source Types
Rural ("0") or Urban ("1") Mode
Units Conversion Factor
Wind Speed Measurement Height above HA (m)
Elevation above MSL of Weather Station (m)
381
124
1 (Recommended)
1 (Optional)
0 (Recommended and Default Value)
0 (Default to Unit 6)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Recommended and Default Value)
0 (Recommended and Default Value)
,68 (Concentration in ppm)
,5 (Recommended)
3 (Recommended)
-------
TABLE 5-7 (Continued)
SHORTZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
GAMMA1
GAMMA2
XRY
DECAY
ROTATE
UTMX
UTMY
Adiabatic Plume Rise Entrainment Coefficient
Stable Plume Rise Entrainment Coefficient
Distance Over Which Rectilinear Lateral Expansion
Occurs (m)
Exponential Decay Coefficient for Physical or
Chemical Depletion (sec )
Angular Displacement of Receptor Grid from True
North (deg)
X Origin of Polar Coordinates (m)
Y Origin of Polar Coordinates (m)
0.60 (Recommended and Default Value)
0.66 (Recommended and Default Value)
50 (Recommended and Default Value)
0 (Recommended and Default Value)
0 (Recommended and Default Value)
0 (Optional)
0 (Optional)
-------
NGROUP in our example is set equal to "7" to enable output of the concen-
trations calculated for each of the six source complexes as well as the
concentrations calculated for the combined sources. The value suggested
for the ISW(2) parameter of "1" directs SHORTZ to print the calculated
hourly average concentrations. If the user is interested only in concen-
trations for longer averaging times, the amount of print output can be
considerably reduced by setting ISW(2) equal to the default value ("0" or
not punched). The ISW(7), ISW(9), ISW(16), ISW(17) and XRY parameters
should always be defined as shown in Table 5-7 for application to the
tideflats area. For SO emission rates in grams per second, TK equal to
"381.68" converts the calculated concentrations to units of ppm. Parameter
KUNR (not shown in Table 5-7) should be entered as "parts per million" to
obtain the correct units label on the output tables. Table 5-7 assumes
that mixing depths from Portage Bay are measured from an elevation HA that
is 3 meters above mean sea level. The Benny's wind measurement height is
127.5 meters above mean sea level so that the wind-speed reference level ZR
is 124.5 meters above HA. We recommend the use of the default values of
the entrainment coefficients GAMMA1 and GAMMA2, which are from Briggs
(1972). However, a GAMMA2 of 0.6 might be justified on the basis of the
more recent Briggs (1975) paper. For the time and distance scales of
concern, we doubt that depletion of SO. by chemical transformations and
deposition is likely to be of concern and have therefore set the DECAY
parameter equal to "0" (no depletion). Because we believe that the
uncertainties in the Benny's wind directions are larger than the approxi-
mate 0.5-degree displacement of the UTM coordinate system from true north,
we see no need to use the ROTATE parameter. The parameters UTMX and UTMY
define the origin in UTM coordinates of the regular receptor array and/or
of the discrete receptor array if polar coordinates are used. For example,
the regular receptor array in Cartesian coordinates can be used in combina-
tion with discrete receptors in a polar coordinate system centered on a
stack whose UTM X and Y coordinates are used to define parameters UTMX and
UTMY.
125
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5.2 LONGZ DISPERSION MODEL METHODOLOGY
Source Inputs
See the discussion of SHORTZ in Section 5.1.
Receptor Inputs
See the discussion of SHORTZ in Section 5.1.
Meteorological Inputs
Table 5-8 lists the seasonal and/or annual meteorological
inputs required by the LONGZ model. The principal meteorological input is
a STAR summary (statistical tabulation of the joint frequency of occurrence
of wind-speed and wind-direction categories, classified according to the
Pasquill stability categories). The best annual STAR summary currently
available to the H. E. Cramer Company for the Tacoma area is the 1972 annual
STAR summary developed by Cramer, _e_t _aJL. (1976) using PSAPCA N26th & Pearl
wind data and concurrent McChord Air Force Base cloud-cover data. This
STAR summary is listed in Appendix C. We suggest the use of the mixing
depths contained in Table 5-6 in LONGZ calculations for the tideflats area.
Based on Seattle normal daily maximum, minimum and average temperatures,
Cramer, et al. assumed the average temperatures for the unstable (A, B and
C), the neutral (D) and the stable (combined E and F) Pasquill stability
categories to be 288, 284 and 279 degrees Kelvin, respectively. We recommend
that the vertical potential temperature gradients given in Table 5-5 and
the LONGZ default values for all of the remaining meteorological inputs be
used in the model calculations for the tideflats area.
Program Control Parameters
Section 4 of the report by Bjorklund and Bowers (1982) provides a
detailed discussion of how to execute the LONGZ computer program. As an
126
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TABLE 5-8
TABLES OF METEOROLOGICAL INPUTS REQUIRED
BY THE LONGZ PROGRAM
Parameter/Table
Definition
Pi,k
E;i,k
li
3z
m;i,k,I
Frequency distribution of wind-speed and wind-
direction categories by stability or time-of-day
categories for the
season
Mean wind speed (m/sec) at height z for the
i wind-speed category
Wind-profile exponent for the i wind-speed
category and k stability or time-of-day
category
Standard deviation of the wind-elevation angle
(rad) for the i wind-speed category and
k stability or time-of-day category
Ambient air temperature (°K) for the k stabi-
lity or time-of-day category and £ season
Vertical potential temperature gradient (°K/m)
for the i wind-speed category and k stabi-
lity or time-of-day category
Median surface mixing depth (m) for the i
windspeed category, k stability or time-of-
day category and H season
127
-------
example, Table 5-9 gives the LONGZ program control parameters for a run
that will use the 1972 annual STAR deck (16 wind-direction categories, 6
wind-speed categories and 5 stability categories) to calculate the annual
average concentrations produced by emissions from the existing sources
(Section 2) at the regular receptors (Appendix B) and at the discrete re-
ceptors discussed in Section 5.1. Parameters ISW(8), ISW(9), ISW(16) and
ISW(17) should always be used as defined in Table 5-9 in LONGZ calculations
for the tideflats area. If TK is defined as "381.68" to obtain SO concen-
trations in units of ppm for emission rates in grams per second, parameter
LUNT (not shown in Table 5-9) should be entered as "parts per million" to
obtain the correct units label on the output tables. The difference in ZR
between Tables 5-7 and 5-9 results from the different ASARCO Benny's (N26th
& Pearl) and PSAPCA N26th & Pearl wind measurement heights above mean sea
level. (Table 5-9 assumes that the STAR summary is based on PSAPCA N26th &
Pearl winds.) Most of the remaining LONGZ program control parameters in
Table 5-9 are identical or analogous to the SHORTZ program control para-
meters which are discussed in Section 5.1.
5.3 ASSESSMENT OF THE PRELIMINARY SHORTZ/LONGZ DISPERSION MODEL
METHODOLOGY
The SHORTZ/LONGZ dispersion model methodology suggested in Sections
5.1 and 5.2 is preliminary because it is based on an incomplete analysis of
all of the existing emissions, meteorological and SO air quality data and
an incomplete model evaluation effort. Nevertheless, the suggested methodology
is based on what is perhaps the most comprehensive analysis to date of
meteorological and SO air quality data from the tideflats area. We believe
that the results of this study in combination with the results of our previous
study of the Tacoma area (Cramer, _et_ al., 1976) provide qualitative support
for the interim use of the methodology outlined in Sections 5.1 and 5.2.
However, this methodology should be used with common sense and a
recognition of the uncertainties identified by the trial SHORTZ calculations
described in this report. For example, the air quality impacts on the
128
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TABLE 5-9
LONGZ PROGRAM CONTROL PARAMETERS FOR AN EXAMPLE PROBLEM
LONGZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
ro
NSOURC
NXPNTS
NYPNTS
NSEASN
NSPEED
NSCTOR
NSTBL
NGROUP
NXWYPT
ISW(l)
ISW(2)
ISW(3)
ISW(4)
No. of Input Sources
No. of Cartesian East-West Receptor Locations
or Polar Radial Receptor Distances
No. of Cartesian North-South Receptor Locations or
Polar Azimuth Bearings
No. of Seasons (Annual Assumed if "1")
No. of Wind-Speed Categories
No. of Wind-Direction Categories
No. of Pasquill Stability Categories
No. of Source Combinations in the Output
No. of Discrete Receptors
Tape Input Is Used (>"0") or Is Not Used ("0")
Tape Output Is Used (>"0") or Is Not Used ("0")
Seasonal Concentrations Are Printed ("1") or Are
Not Printed ("0")
Annual Concentrations Are Printed ("1") or Are Not
Printed ("0")
33 (Optional)
31 (Optional)
25 (Optional)
1 (Recommended and Default Value)
6 (Recommended and Default Value)
16 (Recommended and Default Value)
5 (Recommended and Default Value)
7 (Optional)
15 Optional
0 (Optional and Default Value)
0 (Optional and Default Value)
0 (Optional and Default Value)
1 (Recommended)
-------
TABLE 5-9 (Continued)
LONGZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
Co
o
ISW(5)
ISW(6)
ISW(7)
ISWC8)
TSW(9)
ISW(IO)
ISW(ll)
ISW(12)
ISW(13)
ISW(IA)
ISW(15)
ISW(16)
Specifies Which Inputs Other Than Source Inputs
Are Printed
Card Source Inputs Are Not Printed ("0") or Are
Printed ("1")
Tape Source Inputs Are Not Printed ("0") or Are
Printed ("1")
Define as "1" if Terrain Elevations Are Used
Define as "1" if Wind Speed a Function of height AGL
Rather than Height MSL
Define Print Output Unit Other Than Unit "6"
Define as "1" if STAR Format Differs from Standard
Format
Used Only When Standard Source Input Format Not Used
Cartesian ("0") or Polar ("1") Coordinate Regular
Receptor Array
Cartesian ("0") or Polar ("1") Coordinate Discrete
Receptor Array
Cartesian ("0") or Polar ("1) Source Coordinates
Define as "0" for Same Turbulent Intensities for
All Source Types
1 (Optional)
1 (Recommended)
1 (Recommended)
1 (Recommended)
0 (Recommended and Default Value)
0 (Default to Unit 6)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Optional)
0 (Recommended and Default Value)
-------
TABLE 5-9 (Continued)
LONGZ Input
Parameter
Meaning of Parameter
Optional or Recommended Value
of Parameter
ISW(17)
TK
ZR
HA
GAMMA1
GAMMA2
DECAY
ROTATE
UTMX
UTMY
Rural ("0") or Urban ("1") Mode
Units Conversion Factor
Wind Speed Measurement Height above HA (m)
Elevation above MSL of Weather Station (m)
Adiabatic Plume Rise Entrainment Coefficient
Stable Plume Rise Entrainment Coefficient
Exponential Decay Coefficient for Physical or
Chemical Depletion (sec )
Angular Displacement of Receptor Grid from True
North (deg)
X Origin of Polar Coordinates (m)
Y Origin of Polar Coordinates (m)
0 (Recommended and Default Value)
381.68 (Concentration in ppm)
129.1 (Recommended)
3 (Recommended)
0.60 (Recommended and Default Value)
0.66 (Recommended and Default Value)
0 (Recommended and Default Value)
0 (Recommended and Default Value)
0 (Optional)
0 (Optional)
-------
bluff of emissions from the short stacks at the Kaiser plant and other
tideflats sources probably are overestimated by SHORTZ during hours with
moderate or strong winds from the south-southwest or southwest, but are not
necessarily overestimated during hours with light southerly winds. On the
other hand, our experience in very similar modeling situations (see Appendix H
of Bjorklund and Bowers, 1982) suggests that the concentrations calculated
on the bluff for emissions from the Tacoma City Light and Kaiser tall
stacks during hours with moderate or strong winds from the south-southwest
or southwest are likely to be in good agreement with the actual impacts.
132
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SECTION 6
SUGGESTIONS FOR FUTURE WORK
We believe that the interim SHORTZ/LONGZ dispersion model method-
ology outlined in Section 5 can be improved through analyses of existing
data, additional measurements and more detailed model testing. First,
because ASARCO inadvertently provided EPA Region 10 with the Benny's (N26th
& Pearl) wind data rather than the 46-meter Tower (N26th & Pearl) wind
data, the 46-meter Tower wind data were not received in time to be included
in our study. We therefore recommend that the 46-meter Tower wind data be
evaluated in the same manner as the Benny's wind data to determine if the
Tower winds are more representative of transport winds than the Benny's
winds. We also suggest that the 1981 McChord Air Force Base cloud-cover
data be used with the concurrent PSAPCA N26th & Pearl or ASARCO Benny's
wind speeds to assign stability following the Turner (1964) approach because
the appropriate wind measurement height for this stability classification
scheme is at or near 10 meters. Additionally, we recommend that mixing
depths be estimated from the Washington DOE acoustic sounder measurements
at Portage Bay for comparison with mixing depths estimated from the con-
current upper-air soundings. If a close correspondence is found between
the two sets of mixing depths, the acoustic sounder data could be routinely
reduced to obtain valuable information on the depth of the surface mixing
layer throughout the day.
The Kaiser S0? air quality data provided us with the only
indication of the air quality impact within the tideflats and on the bluff
northeast of the tideflats of emissions from the existing sources. Because
it is our understanding that the Kaiser monitoring program has been termin-
ated, we suggest that PSAPCA consider the possibility of locating an SO
air quality monitor north or north-northeast of the Kaiser plant. Also,
because the results of our limited SHORTZ calculations for the Kaiser Plant
site monitor indicate that our interim modeling methodology may underestimate
133
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concentrations near the Kaiser plant due to an overestimation of buoyant
plume rise for the dry scrubber stacks, we recommend that this monitor be
placed as close to the Kaiser plant as is practical. Air quality monitoring
on the bluff following the construction of the Tacoma City Light cogener-
ation plant and/or the Kaiser plant expansion should provide additional
data needed to test model performance. Finally, we are unable to reconcile
the SO emissions reported by ASARCO for some of the days during the 1981
air stagnation episodes with the observed SCL concentrations. As pointed
out by PSAPCA (Carson, 1982), emissions from the ASARCO smelter are
possible when the in-stack SO monitor shows zero emissions. We there-
fore recommend that efforts be made to obtain more detailed information on
S09 emissions from all of the sources in and adjacent to the tideflats
area during the period 23 through 25 October 1981. Special attention
should be given to the question of what stack and/or low-level emissions
can occur at the ASARCO smelter during hours when the emission rate
reported for the Main Stack is zero or very low.
We believe that the above recommendations for future work can
possibly be accomplished with the resources currently available to EPA
Region 10, the Washington DOE and PSAPCA. In our opinion, the implemen-
tation of these recommendations should lead to an improvement in the
accuracy of predictions made using the interim SHORTZ/LONGZ air quality
model methodology outlined in Section 5. However, it should be recognized
that the implementation of the above recommendations will not necessarily
result in the optimum SHORTZ/LONGZ model methodology for use in the Tacoma
tideflats area. Also, models other than the SHORTZ/LONGZ models may be
necessary to address some critical meteorological regimes such as air stag-
nation episodes. Table 6-1 briefly summarizes the advantages and disad-
vantages of several possible approaches that could assist in the development
of an optimum SO air quality model methodology for the Tacoma tideflats
area. Inspection of Table 6-1 indicates that the current major impediment
to the development of a model methodology is the very limited knowledge of
the spatial and temporal variations of meteorologial conditions and SO
air quality within the tideflats area. Thus, all of the possible approaches
134
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TABLE 6-1
ADVANTAGES AND DISADVANTAGES OF POSSIBLE APPROACHES TO AID
IN THE DEVELOPMENT OF AN S02 AIR QUALITY MODEL
METHODOLOGY FOR THE TACOMA TIDEFLATS AREA
Approach
Advantages
Disadvantages
Field Measurement Program
to define empirical
source-receptor relation-
ships. Inject an inert
tracer (for example, SF )
into emissions from eacn
source, one at a time.
Alternately, simultaneous-
ly inject multiple inert
tracers into emissions
from the various sources
so that the impacts of the
various sources can be
distinguished. Compile
detailed records of oper-
ating conditions and emis-
sions parameters for each
source. Make very de-
tailed meteorological and
tracer air quality
measurements in and ad-
jacent to the tideflats
area.
1. Given a sufficient
data base, monitoring
could be used in place of
modeling for the existing
sources.
2. New or modified air
quality modeling tech-
niques uniquely appli-
cable to the tideflats
area could possibly be
developed.
3. The resulting data
base would be a valuable
one for use in model de-
velopment and evaluation
studies.
1. A measurement program
of this type would pro-
bably cost a million
dollars or more.
2. The field measure-
ment program probably
would have to cover a
period of at least 1
year in order to iden-
tify all critical mete-
orological regimes.
3. Current land use and
the topography will make
it very difficult to
place tracer air quality
monitors at all of the
desired locations.
4. The cooperation of
all of the sources in
the tideflats area is
necessary.
5. Empirical source-
receptor relationships
cannot necessarily be
extrapolated to new
sources with different
emissions characteris-
tics.
Numerical Wind Field
Models to define wind
fields and plume tra-
jectories under critical
meteorological conditions
1. This is a relatively
inexpensive approach.
2. This approach may
define areas where addi-
tional monitoring is
needed.
1. Because of the com-
plexity of the terrain
and the desired reso-
lution of the wind field,
it may be difficult to
obtain converged (steady-
state) model solutions.
135
-------
TABLE 6-1 (Continued)
Approach
Advantages
Disadvantages
Numerical Wind Field
Models (Continued)
3. This approach may
provide qualitative in-
sight into source-
receptor relationships
under some meteorologi-
cal conditions.
4. This approach may
assist in optimizing
meteorological inputs
to existing models
such as the SHORTZ/
LONGZ models.
2. Wind field models
will not necessarily ap-
ply under all meteoro-
logical conditions, es-
pecially light wind
conditions.
3. The wind measure-
ments required to evalu-
ate and verify the per-
formance of wind field
models would have to be
collected.
Numerical Dispersion
Model such as a variable-
trajectory Gaussian puff
model to calculate ambient
SO concentrations.
1. This approach can
consider the variations
in space and time of
winds, turbulent inten-
sities, mixing depths
and other important met-
eorological parameters.
2. This approach can be
used during periods of
very light or calm winds,
1. The current meteoro-
logical measurements are
not sufficient to imple-
ment this type of model.
2. The basic time incre-
ment might have to be as
short as 5 to 10 minutes
to address some meteoro-
logical conditions such
as periods of light and
variable winds.
3. The model could be
very costly to execute
in an operational manner,
especially if the inter-
polated wind fields are
required to be mass con-
sistent.
Additional Measurements
to define the meteorology
and SO air quality of
the Tacoma tideflats
area.
1. A Doppler acoustic
sounder located in the
tideflats could in
principle measure all
SHORTZ inputs without
recourse to discrete
stability categories.
1. Although this meas-
urement technique appears
very promising, we know
of no operational studies
in which all meteoro-
logical inputs were or
are measured by a Doppler
136
-------
TABLE 6-1 (Continued)
Approach
Advantages
Disadvantages
.dditional Measurements
Continued)
These inputs include
vertical profiles of
wind direction, wind
speed, the turbulent
intensities and the
depth of the surface
mixing layer.
2. A minimum of three
30-meter towers—with
wind, turbulence and
temperature instrumen-
tation at the 10-meter
and 30-meter levels—
located at the center
and either side of the
tideflats area would
provide a better defin-
ition of the variation
of meteorological con-
ditions with location
within the tideflats.
3. Minisonde releases
from the tideflats made
four times per day (0700,
1300, 1900 and 0100 PST)
during a 1-year period
could be used to estab-
lish a climatological
summary of the thermal
stratifications within
the tideflats and could
be compared with acoustic
sounder (tideflats and/or
Portage Bay) and other
measurements.
4. Additional SO air
quality monitors within
the tideflats (for ex-
ample, north-northeast
or south-southwest of
major sources such as
Kaiser) and on the bluff
acoustic sounder. The
The practicality of this
approach can only be de-
termined by experience.
2. Current land use
could make it difficult
to find representative
sites within the tide-
flats area for acoustic
sounders or instrumented
meteorological towers.
3. Accurate wind-
direction measurements
during periods of light
winds are difficult, but
are necessary if source-
receptor relationships
are to be understood.
4. Towers with measure-
ment heights above
ground level as high as
100 meters will not
necessarily define winds
at the plume heights for
emissions from the taller
stacks.
5. A detailed analysis
of the measurements will
be required to develop
or refine an air quality
model methodology.
137
-------
TABLE 6-1 (Continued)
Approach
Advantages
Disadvantages
Additional Measurements
(Continued)
to the north-northeast
of the two tall stacks
in the tideflats area
could significantly im-
prove our understanding
of the space and time
variations of SO con-
centrations within the
tideflats.
5. Accurate estimates of
ASARCO stack and low-level
S02 emissions could help to
isolate the effects on air
quality of ASARCO emissions
from the effects of emis-
sions from the sources
within the tideflats.
138
-------
in Table 6-1 except the use of a numerical wind field model require
additional measurements, and additional measurements are the only means to
verify the predictions of a wind field model. Because of the importance of
additional measurements, Table 6-1 provides some specific suggestions on
the types of measurements that are needed.
139
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140
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REFERENCES
American Meteorological Society, 1978: Accuracy of dispersion models: A
position paper of the 1977 AMS Committee on Atmospheric Turbu-
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Anderson, J. K., 1982: Private communication (7 June 1982 letter to
Robert B. Wilson, U. S. Environmental Protection Agency,
Region 10).
Benkley, C. W. and L. L. Schulman, 1979: Estimating hourly mixing depths
from historical meteorological data. Journal of Applied Meteor-
ology, 18_, 772-780.
Bjorklund, J. R. and J. F. Bowers, 1979: User's instructions for the
SHORTZ and LONGZ computer programs. Technical Report TR-79-131-
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Bjorklund, J. R. and J. F. Bowers, 1982: User's instructions for the
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Briggs, G. A., 1971: Some recent analyses of plume rise observations. In
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Briggs, G. A., 1975: Plume rise predictions. Lectures on Air Pollution
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REFERENCES (Continued)
Calder, K. L., 1971: A climatological model for multiple source urban air
pollution. Proc. 2nd Meeting of the Expert Panel on Air Pollu-
tion Modeling, NATO Committee on the Challenges of Modern So-
ciety, Paris, France, July 1971, 33.
Caniparoli, D. G., 1982: Private communication (14 May 1982 letter to
J. F. Bowers, H. E. Cramer Company, Inc.).
Carson, B., 1982: Private communication (23 August 1982 letter to R. B.
Wilson, U. S. Environmental Protection Agency, Region X).
Cramer, H. E. , et_ _at_. , 1972: Development of dosage models and concepts.
Final Report under Contract DAAD09-67-C-0020(R) with the U. S.
Army, Deseret Test Center Report DTC-TR-72-609, Fort Douglas,
Utah.
Cramer, H. E., H. V. Geary and J. F. Bowers, 1975: Diffusion-model calcu-
lations of long-term and short-term ground-level SO concentra-
tions in Allegheny County, Pennsylvania. EPA Report 903/9-75-
018 (NTIS Accession No. PB 245262/AS), U. S. Environmental Pro-
tection Agency, Region III, Philadelphia, Pennsylvania.
Cramer, H. E., J. F. Bowers and H. V. Geary, 1976: Assessment of the air
quality impact of SO emissions from the ASARCO-Tacoma smelter.
EPA Report No. EPA 910/9-76-028, U. S. Environmental Protection
Agency, Region X, Seattle, Washington.
Environmental Protection Agency, 1969: Air Quality Display Model. Pre-
pared by TRW Systems Group, Washington, D.C., available as PB
189-194 from the National Technical Information Service,
Springfield, Virginia.
Environmental Protection Agency, 1978: Guideline on air quality models.
EPA Report No. EPA-450/2-78-027, OAQPS No. 1.2-080. U. S.
Environmental Protection Agency, Research Triangle Park, North
Carolina.
Gorr, W. L. and R. W. Dunlap, 1977: Characterization of steady wind inci-
dents for air quality management. Atm. Env., 11, 59-64.
Hoel, P. G., 1971: Introduction to Mathematical Statistics, John Wiley
& Sons, Inc., New York.
Holzworth, G. C., 1972: Mixing heights, wind speeds and potential for
urban air pollution throughout the contiguous United States.
Publication No. AP-101, U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
142
-------
REFERENCES (Continued)
Huber, A. H. and W. H. Snyder, 1976: Building wake effects on short stack
effluents. Paper presented at the Third Symposium on Atmospher-
ic Turbulence, Diffusion and Air Quality, Raleigh, North
Carolina, October 19-22, 1976.
Knechtel, K. B. , 1982: Private communication (20 April 1982 letter to
J. F. Bowers, H. E. Cramer Company, Inc.).
Osipov. Y. S., 1972: Diffusion from a point source of finite time of ac-
tion. In AICE Survey of USSR Air Pollution Literature - Volume
XII, distributed by National Technical Information Service,
Springfield, Virginia.
Pasquill, F., 1962: Atmospheric Diffusion. D. Van Nostrand Co., Ltd.,
London, 297.
Pasquill, F., 1974: Atmospheric Diffusion (Second Edition). Ellis Horwood
Limited, Sussex, England, 429.
Puget Sound Air Pollution Control Agency, 1982: Air contaminant emission
sources for Tacoma City Light Study. Engineering Division, Puget
Sound Air Pollution Control Agency, Seattle, Washington.
Schmeil, P- F., 1982: Private communication (30 April 1982 letter to R, B.
Wilson, U. S. Environmental Protection Agency, Region 10).
Schulman, L. L. and J. S. Scire, 1980: Buoyant Line and Point Source (BLP)
Dispersion Model user's guide. Document P-7304B, Environmental
Research & Technology. Inc., Concord, Massachusetts.
Turner, D. B., 1964: A diffusion model for an urban area. J. Appl. Mete-
or. , 3/1), 83-91.
Watson, R. B., 1982: Private communication (13 May 1982 letter to
R. Wilson, U. S. Environmental Protection Agency, Region 10).
Wilson, R. B., 1982a: Private communication (21 April 1982 letter to J. F.
Bowers, H. E. Cramer Company, Inc.).
Wilson, R. B., 1982b: Private communication (15 June 1982 telephone con-
versation with J. F. Bowers, H. E. Cramer Company, Inc.).
Wilson, R. B., 1982c: Private communication (19 October 1982 letter to J.
F. Bowers, H. E. Cramer Company, Inc.).
143
-------
144
-------
APPENDIX A
MATHEMATICAL MODELS USED TO CALCULATE
GROUND-LEVEL CONCENTRATIONS
A.I INTRODUCTION
The computerized diffusion models described in this appendix fall
into two general categories: (1) A short-term model for calculating time-
averaged ground-level concentrations for averaging times of 1, 3, 8, and 24
hours; (2) A long-term model for calculating seasonal and annual ground-
level concentrations. Both the short term and long-term concentrations
models are modified versions of the Gaussian plume model for continuous
sources described by Pasquill (1962). In the short-term model, the plume
is assumed to have Gaussian vertical and lateral concentration distri-
butions. The long-term model is a sector model similar in form to the
Environmental Protection Agency's Climatological Dispersion Model (Calder,
1971) in which the vertical concentration distribution within a sector is
rectangular (a smoothing function is used to eliminate sharp discontinuities
at the sector boundaries). Vertical plume growth (a ) in the short-term
Z
and long-term models and lateral plume growth (a ) in the short-term model
are calculated by using turbulent intensities in simple power-law expressions
that include the effects of initial source dimensions. In both the short-term
and long-term models, buoyant plume rise is calculated by means of the
Briggs (1971; 1972) plume-rise formulas, modified to include the effects of
downwash in the lee of the stack during periods when the wind speed at
stack height equals or exceeds the stack exit velocity. An exponent law is
used to adjust wind speed to the source height for plume-rise calculations
and to the plume stabilization height for the concentration calculations.
Both the short-term and the long-term models contain provisions to account
for the effects of complex terrain.
Table A-l lists the hourly meteorological inputs required by
the short-term concentration model. Lateral and vertical turbulent
A-l
-------
intensities a' and a' may be directly specified or may be assigned on
A AJ
the basis of the Pasquill stability category (see Section 3 of Cramer,
et_ a^., 1975). The Pasquill stability cateogry is determined from
surface weather observations using the Turner (1964) wind-speed and
solar-index values. Mixing depths may be obtained from rawinsonde or
pibal measurements, or they may be assigned on the basis of tabulations
of the frequency of occurrence of wind speed and mixing depth (available
from the National Climatic Center for synoptic rawinsonde stations).
Potential temperature gradients may be obtained from measurements or
assigned on the basis of climatology-
Table A-2 lists the meteorological inputs required by the
long-term concentration model. Joint-frequency distributions of wind-
speed and wind-direction categories, classified according to the Pasquill
stability categories, are available from the National Climatic Center.
Alternately, surface wind observations may be analyzed to generate wind-
frequency distributions by time-of-day categories (night, morning,
afternoon and evening). Vertical turbulent intensities may be deter-
mined from a climatology of actual measurements or may be assigned on
the basis of the Pasquill stability categories. Median mixing depths
may be determined from the seasonal tabulations of the frequency of
occurrence of wind-speed and mixing depth prepared by the National
Climatic Center. Vertical potential temperature gradients may be as-
signed to the combinations of wind-speed and stability or time-of-day
categories on the basis of climatology.
Table A-3 lists the source input parameters required by the
short-term and long-term diffusion models. As shown by the table, the
computerized short-term and long-term models calculate ground-level
concentrations produced by emissions from stacks, building vents and
roof monitors, and from area sources. Both the short-term and long-term
models also use a Cartesian coordinate system (usually the Universal
Transverse Mercator system) with the positive X axis directed toward the
east and the positive Y axis directed toward the north.
A-2
-------
TABLE A-l
HOURLY METEOROLOGICAL INPUTS REQUIRED BY THE
SHORT-TERM CONCENTRATION MODEL
Parameter
Definition
u.
R
H
m
li
3z
Mean wind speed at height z (m/sec)
K
Mean wind direction at height z (deg)
R
Wind-profile exponent
Wind azimuth-angle standard deviation in radians
Wind elevation-angle standard deviation in radians
Ambient air temperature ( K)
Depth of surface mixing layer (m)
Vertical potential temperature gradient (°K/m)
A-3
-------
TABLE A-2
METEOROLOGICAL INPUTS REQUIRED BY THE
LONG-TERM CONCENTRATION MODEL
Parameter
Definition
p (Table)
aE;i,k
T (Table)
a; k,£
/39\
VaTJ
H . (Table)
u (z } (Table)
IV 1
Frequency distribution of wind-speed and
wind-direction categories by stability or
time-of-day categories for the £tn season
Wind-profile exponent for each stability or
time-of-day category and ±t"- wind-speed cate-
gory
Standard deviation of the wind-elevation
angle in radians for the i1- wind-speed
category and ktn stability or time-of-day
category
Ambient air temperature for the k stabil-
ity or time-of-day category and fi,t" season
Vertical potential temperature gradient for
the itn wind-speed category and ktn stability
or time-of-day category (°K/m)
Median surface mixing depth for the i^ wind-
speed category, kth stability or time-of-day
category and JttlT season (m)
Mean wind speed at height z for the i wind-
speed category (m/sec)
A-4
-------
TABLE A-3
SOURCE INPUTS REQUIRED BY THE SHORT-TERM
AND LONG-TERM CONCENTRATION MODELS
Parameter
Definition
Stacks
Q
X, Y
z
s
h
v
T
Building Sources
Q
X, Y
z
h
L
W
6
Area Sources
Q
X, Y
Pollutant emission rate (mass per unit time)
X and Y coordinates of the stack (m)
Elevation above mean sea level of the base of the
stack (m)
Stack height (m)
3
Actual volumetric emission rate (m /sec)
Stack exit temperature ( K)
Stack inner radius (m)
Pollutant emission rate (mass per unit time)
X and Y coordinates of the center of the building (m)
Elevation above mean sea level of the base of the
building (m)
Building height (m)
Building length (m)
Building width (m)
Angle measured clockwise between north and the
long side of the building (deg)
Pollutant emission rate (mass per unit time)
X and Y coordinates of the center of the area
source (m)
Elevation above mean sea level of the area source (m)
A-5
-------
TABLE A-3 (Continued)
Parameter
Definition
Area Sources
(Continued)
L
W
6
Characteristic vertical dimension of the area
source (m)
Length of the area source (m)
Width of the area source (m)
Angle measured clockwise between north and the
long side of the area source (deg)
A-6
-------
A.2 PLUME-RISE FORMULAS
The effective stack height H of a buoyant plume is given by the
sum of the physical stack height h and the buoyant rise Ah. For an adiabatic
or unstable atmosphere, the buoyant rise Ati is given by
u {h} V 2Y,
(iOh)
2/3
(A-l)
where the expression in the brackets is from Briggs (1971; 1972) and
u{h} = the mean wind speed at the stack height h (m/sec)
Y, = the adiabatic entrainment coefficient ~0.6 (Briggs, 1972)
/ Q
The initial buoyancy flux (m /sec )
(A-2)
3
V = The volumetric emission rate of the stack (m /sec)
= IT r w
r = inner radius of stack (m)
w = stack exit velocity (m/sec)
2
g = the acceleration due to gravity (m/sec )
T = the ambient air temperature ( K)
3.
T = the stack exit temperature ( K)
The factor f, which limits the plume rise as the mean wind speed at stack
height approaches or exceeds the stack exit velocity, is defined by
A-7
-------
f
; u {h} < w/1.5
3w - 3u{h> \
w
; w/1.5 < u {h} <
; u {h} > w
w
(A-3)
The empirical correction factor f is generally not applied to stacks with
Froude numbers less than about unity. The corresponding Briggs (1971)
rise formula for a stable atmosphere (potential temperature gradient
greater than zero) is
Ah
3F
6F
1/3
_u{h}y0 S
1 - cos
/10S
— -
1/2
u{h}
-1/2
;ir u{h} S ' <10h
1/3
-1 /?
;TT u{h} S ' > lOh
>• (A-4)
where
'2
S
the stable entrainment coefficient~0.66 (Briggs, 1972)
T 3z
a
— = vertical potential temperature gradient (°K/m)
3z
The entrainment coefficients y and y are based on the suggestions of
Briggs (1972). It should be noted that Equation (A-4) does not permit
A-f
-------
the calculated stable rise Ah to exceed the adiabatic rise Ah as
s *••
the atmosphere approaches a neutral stratification (36/3z approaches 0)
A procedure of this type is recommended by Briggs (1972).
A. 3
SHORT-TERM CONCENTRATION MODEL
A.3.1
Elevated Sources
The atmospheric dispersion model used to calculate hourly
average ground-level concentrations downwind from an elevated continuous
source is given by
K Q
TV u{H}o a
y
{Vertical Term} {Lateral Term} {Decay Term} (A-5)
where
K
Q
u{H}
a ,a
y z
scaling coefficient to convert input parameters to
dimensionally consistent units
source emission rate (mass per unit time)
mean wind speed at the plume stabilization height H (m/sec)
standard deviations of the lateral and vertical con-
centration distributions at downwind distance x (m)
The Vertical Term refers to the plume expansion in the vertical
or z direction and includes a multiple reflection term that limits
cloud growth to the surface mixing layer.
{Vertical Term}
\exp
+ exp
n=l
exp
. 2n H
1 I m
, /2n H - HN
1 / m
H
(A-6)
A-9
-------
where H is the depth of the surface mixing layer. The exponential terms
m
in the infinite series in Equation (A-6) rapidly approach zero near the
source. At the downwind distance where the exponential terms exceed exp(-lO)
for n equal 3, the plume has become approximately uniformly mixed within
the surface mixing layer. In order to shorten computer computation time,
Equation (A-6) is changed to the form
a
{Vertical Term} = —^—- (A-7)
/n
m
beyond this point. Equation (A-7) changes the form of the vertical concen-
tration distribution from Gaussian to rectangular. If H exceeds H ,
0 m
the Vertical Term is set equal to zero which results in a zero value for
the ground-level concentration.
The Lateral Term refers to the crosswind expansion of the plume
and is given by the expression
{Lateral Term} = exp
2 10
(A-8)
where y is the crosswind distance from the plume centerline to the point
at which concentration is calculated.
The Decay Term, which accounts for the possibility of pollutant
removal by physical or chemical processes, is of the form
{Decay Term} = exp [ - ty x/u{H} ] (A-9)
where
\l> = the washout coefficient A (sec ) for precipitation scav-
enging
A-10
-------
0.692
T '
1/2
where T,/9 is the pollutant half life in seconds
for physical or chemical removal
= 0 for no depletion (ty is automatically set to zero by
the computer program unless otherwise specified)
In the model calculations, the observed mean wind speed IL is
adjusted from the measurement height
^
K
to the source height h for
plume-rise calculations and to the stabilization height H for the con-
centration calculations by a wind-profile exponent law
u{z} =
(A-10)
The exponent p, which is assigned on the basis of atmospheric stability,
ranges from about 0.1 for very unstable conditions to about 0.4 for very
stable conditions.
According to the derivation in the report by Cramer, e_t^ ad. (1972),
.rd deviation c
given by the expression
the standard deviation of the lateral concentration distribution a is
°y{x} = °AXry
x + x - x (1-a)
y ry"
ax
ry
(A-ll)
x
ax
,1/a
ry I x a:
y \ ry A/
"yR
; — ^-7- < x
-
aA -
R
x,, + x (1-a) ; —7— >
R ryv a
x
ry
(A-12)
A-ll
-------
where
ry
a
= the standard deviation of the wind-azimuth angle in
radians
= distance over which rectilinear plume expansion occurs
downwind from an ideal point source (~50 meters)
= the standard deviation of the lateral concentration
distribution at downwind distance x (m)
K
= the lateral diffusion coefficient (~0.9)
The virtual distance x is not permitted to be less than zero. The lat-
y
eral turbulent intensity a' may be specified directly or may be assigned
A
on the basis of the Pasquill stability category -
Following the derivation of Cramer, et al. (1972) and setting
the vertical diffusion coefficient 3 equal to unity, the standard devi-
ation of the vertical concentration distribution a is given by the expres-
z
sion
= al
(A-13)
x
zR
a
zR
ZR
R
(A-14)
where
zR
= standard deviation of the wind-elevation angle in
radians
= the standard deviation of the vertical concentration
distribution at downwind distance x (m)
A-12
-------
The vertical turbulent intensity o' may also be obtained from direct
&
measurements or may be assigned according to the Pasquill stability cat
egories. When a' values corresponding to the Pasquill stability cate
£j
gories are entered in Equation (A-13), the resulting curves will differ
from the corresponding Pasquill-Gifford curves in that Equation (A-13)
assumes rectilinear expansion at all downwind distances. Thus, a
z
values obtained from Equation (A-13) will be smaller than the values
obtained from the Pasquill-Gifford A and B curves and larger than the
values obtained from the D, E and F curves at long downwind distances.
However, the multiple reflection term in Equation (A-6), which confines
the plume to the surface mixing layer, accounts for the behavior of the
D, E and F curves (decrease in the expansion rate with distance) in
a manner that may be related to the meteorology of the area.
Following the recommendations of Briggs (1972), the lateral
and vertical standard deviations of a stabilized buoyant plume are
defined by
°
zR
0.5 Ah
2.15
(A-15)
The downwind distance to stabilization
is given by
XR
lOh
TT u{h} S"1/2 ; > 0
lOh
and IT
1/2
; > 0 and IT
< lOh
> lOh
(A-16)
A-13
-------
A.3.2 Application of the Short-Term Model'to Low-level
Emissions
The short-term diffusion model in Section A.3.1 may be used to
calculate ground-level concentrations resulting from low-level emissions
such as losses through building vents. These emissions are rapidly dis-
tributed by the cavity circulation of the building wake and quickly
assume the dimensions of the building. Ground-level concentrations are
calculated by setting the buoyancy parameter F equal to zero. The
standard deviation of the lateral concentration distribution at the
source a is defined by the building crosswind dimension y divided
yo o
by 4.3. The standard deviation of the vertical concentration distribution
at the source is obtained by dividing the building height by 2.15. The
initial dimensions a and O are assumed to be applicable at the
yo zo
downwind edge of the building. These procedures are in good agreement
with the results of recent wind-tunnel experiments reported by Huber and
Snyder (1976). It should be noted that separate turbulent intensities
O' and cr' may be defined for the low-level sources to account for the
A ij
effects of surface roughness elements and heat sources.
A.3.3 Short-Term Concentration Model for Area Sources
The atmospheric dispersion model used to calculate ground-
level concentrations at downwind distance x from the downwind edge of
an area source is given by the expression
-IT r\
X(x, y) = —— * {Vertical Term}
/2¥ u{h} a {x} y
z o
(A-17)
{Lateral Term} {Decay Term}
where
Q = area source strength in units of mass per unit time
Y = crosswind source dimension (m)
A-14
-------
a' x
E o
x < 3 x
In
aE(x)+h
/2)+h
h o
x > 3 x
— o
(A-18)
x = alongwind dimension of the area source (m)
h = the characteristic height of the area source (m)
The Vertical Term for an area source is given by
{Vertical Term} =
1+2
j exp
n=l
1 /2n H \ " 1 / 6Hm \
\ X / \ Z '
10
n a {x}
z
2H
m
6H
(A-19)
The Lateral Term is given by the expression
{Lateral Term} =
-------
and
ay{x} = a; (x+xo/2)
(A-21)
The Decay Term is given by Equation (A-9) above.
The concentration at points interior to the area source is
given by
2 K Q
/2rT u{h} x y a'
o o
'In
(x'+D+h
+ h J
{Vertical Term} (A-22)
where
x' = distance downwind from the upwind edge of the area source (m)
A. 4
LONG-TERM CONCENTRATION MODEL
A.4.1
Elevated Sources
The atmospheric dispersion model for elevated point and volume
sources is similar in form to the Air Quality Display Model (Environmental
Protection Agency, 1969) and the Climatological Dispersion Model (Calder,
1971). In the model, the area surrounding a continuous source of pollu-
tants is divided into sectors of equal angular width corresponding to the
class intervals of the seasonal and annual frequency distributions of wind
direction. The emission rate during a season or year is partitioned
according to the relative wind-direction frequencies. Ground-level con-
centration fields for each source are translated to a common reference
coordinate grid system and summed to obtain the total due to all emissions.
For a single source, the mean seasonal concentration at a point (r, 6) is
given by
A-16
-------
9}
2 K Q
IT r A0'
S{0}V
1,K,
(A-23)
= exp
H
2 \a
z;l,k,
00
E
2n H . . -H.
m;i,k,£
+ exp
'2n H . . +H. .
m;i,k,£ i,k,£
a . ,
z;i,k,£
(A-24)
where
A61
S{0}
frequency of occurrence of the i wind-speed category,
jth wind-direction category and kth stability or time-
of-day category for the &th season
the sector width in radians
a smoothing function
S{6} =
A0'-|e'.-e'
A0f
e'.-e' | < A01
3^-0'| > A0'
(A-25)
J
0'
the angle measured in radians from north to the center-
line of the jth wind-direction sector
the angle measured in radians from north to the point
(r,9)
A-17
-------
As with the short-term model, the Vertical Term given by Equation
(A-24) is changed to the form
/2? a .
z;x,tc,x, (A-26)
2H .
when the exponential terms in Equation (A-24) exceed exp(-lO) for n equal
3. The remaining terms in Equations (A-23) are identical to those previously
defined in Section A. 3.1 for the short-term model, except that the turbulent
intensities and potential temperature gradients may be separately assigned
to each wind-speed and/or stability (or time-of-day) category; the ambient
air temperatures may be separately assigned to each stability (or time-of-
day) category for each season; and the surface mixing depths may be separately
assigned to each wind-speed and/or stability (or time-of-day) category for
each season.
As shown by Equation (A-25) , the rectangular concentration distrib-
ution within a given angular sector is modified by the function S{6} which
smoothes discontinuities in the concentration at the boundaries of adjacent
sectors. The centerline concentration in each sector is unaffected by con-
tributions from adjacent sectors. At points off the sector centerline, the
concentration is weighted function of the concentration at the centerline of
the sector in which the calculation is being made and the concentration at
the centerline of the nearest adjoining sector.
The mean annual concentration at the point (r,9) is calculated from
the seasonal concentrations using the expression
X£{r,6} (A-27)
SL=1
A-18
-------
A.4.2 Application of the Long-Term Model to Low-Level Emis-
sions
Long-term ground-level concentrations produced by low-level emis-
sions are calculated from Equation (A-23) by setting the buoyancy parameter
F equal to zero. The standard deviation of the vertical concentration dis-
tribution at the downwind edge of the building a is defined as the
zo
building height divided by 2.15. Separate vertical turbulent intensities
al may be defined for the low-level sources to account for the effects of
Cj
surface heat sources and roughness elements. A virtual point source is used
to account for the initial lateral dimension of the source in a manner iden-
tical to that described below for area sources.
A.4.3
Long-Term Concentration Model for Area Sources
The mean seasonal concentration at downwind distance r with
respect to the center of an area source is given by the expression
ro}
2 K 0
/2? R A91
u {h} a
S{0} V.
z;i,k
(A-28)
exp -
- r
)/u.{h}]
where
R = radial distance from the virtual point source to the receptor
2\l/2
Xy/ y /
= distance from source center to receptor, measured along the
sector centerline (m)
= effective source radius (m)
A-19
-------
y =
X =
y
lateral distance from the sector centerline to the receptor (m)
lateral virtual distance (m)
r cot
o 2
(A-29)
z;i,k
2aL
In
al . . (V+r } + h
E;i,k\ o/
r <
o
6r
al . , (r'-r ^ + h
E;i,kv o/
a' . r' + h
E;i,k
> 6r
(A-30)
V
i,k,£
1+2 exp
L^i
n=l
.. / 2n H
_! [ m; i,k, £
2 I a . ,
\ z;i,k
. /6H . . . \2
. If m;i,k,£ A ^ 1Q
. .
z;i,k
H
TJ
m;i,k,£
m;i,k,£
< 10
(A-31)
and the remaining parameters are identical to those previously defined.
For points interior to the area source, the seasonal average
concentration is given by the expression:
v-v^
x y
0 0
£
(A-32)
A-20
-------
where
r" = the downwind distance, measured along the sector centerline
from the upwind edge of the area source (m)
A.5 APPLICATION OF THE SHORT-TERM AND LONG-TERM CONCENTRATION MODELS
IN COMPLEX TERRAIN
The short-term and long-term concentration models described in
Sections A.3 and A.4 are strictly applicable only for flat terrain where
the base of the stack (or the building source) and the ground surface down-
wind from the source are at the same elevation. However, both models
may also be applied to complex terrain by defining effective stabilization
heights and mixing depths. The following assumptions are made in the model
calculations for complex terrain:
• The top of the surface mixing layer extends over the
calculation grid at a constant height above mean sea
level
• Ground-level concentrations at all grid points above
the top of the surface mixing layer are zero
• Plumes that stabilize above the top of the surface
mixing layer do not contribute to ground-level con-
centrations at any grid point (this assumption also
applies to flat terrain)
In order to determine whether the stabilized plume is contained
within the surface mixing layer, it is necessary to calculate the mixing
depth H*{z } at the source from the relationship
m s
H*{z } = (H + z - z\ (A-33)
m * s' \ m a s/
A-21
-------
where
m
the depth of the surface mixing layer measured at a point
with elevation z above mean sea level
a
the height above mean sea level of the source
Equation (A-33) is represented schematically in Figure A-l. As shown by
the figure, the actual top of the surface mixing layer is assumed to
remain at a constant elevation above mean sea level. If the height H of
the stabilized plume above the base of the stack is less than or equal
to H*{z }, the plume is defined to be contained within the surface mixing
m s
layer.
The height H of the stabilized plume above mean sea level is
given by the sum of the height H of the stabilized plume above the base
of the stack and the elevation z of the base of the stack. At any eleva-
tion z above mean sea level, the effective height H'{z} of the plume cen-
terline above the terrain is then given by
H'{z} =
H -z; H -z>0
o ' o —
0 ; H - z < 0
o
(A-34)
The effective mixing depth H'{z} above a point at elevation z
m
above mean sea level is defined by
H;{Z} =
H
m
; z _> z
3.
H +z - z ; z < z
ma a
(A-35)
A-22
-------
Top of Mixing Layer
Mixing Depth
Mixing Depth Measured
»• at Airport Equals
Minimum Depth
(No calculations /
made for grid
points with /
terrain elevations
above top of /
mixing layer (MSL)
at airport)
Assigned to
Source
Airport
Elevation
FIGURE A-IU Mixing depth H*{z } used to determine whether the stabilized plume is contained within the
surface mising layer.
-------
Figure A-2 illustrates the assumptions implicit in Equation (A-35). For
grid points at elevations below the airport elevation, the effective mix-
ing depth H'{z} is allowed to increase in a manner consistent with Figure
m
A-l. However, in order to prevent a physically unrealistic compression
of plumes as they pass over elevated terrain, the effective mixing depth
is not permitted to be less than the mixing depth measured at the airport.
It should be noted that the concentration is set equal to zero for grid
points above the actual top of the mixing layer (see Figure A-l).
The terrain adjustment procedures also assume that the mean wind
speed at any given height above sea level is constant. Thus, the wind
speed u above the surface at a point with elevation z above mean sea
i\- 3.
level is adjusted to the stack height for the plume-rise calculations
by the relationship
u(h) =
; h < z + z^
o a R
(A-36)
where hQ is the height above mean sea level of the top of the stack. Sim-
ilarly, the wind speed u{H} used in the concentration calculations is given
by
u{H} H
; Ho ^ Za + ZR
o a K
u ; H < z + z
R o a R
(A-37)
A-24
-------
N3
Effective Top of Mixing Layer
Effective
Mixing Depth
Mixing Depth Measured
- at Airport Equals
Minimum Depth
(No calculations
made for grid
points with
terrain elevations
above top of
mixing layer (MSL)
at airport
m
Assigned to
Grid Point
FIGURE A-2.. Effective mixing depth H^{z}assigned to grid points for the concentration calculations.
-------
APPENDIX B
RECEPTOR INPUTS FOR THE TACOMA TIDEFLATS AREA
As discussed in Section 5.1, the maximum SO air quality impacts
of emissions from the existing and proposed sources located in and adjacent
to the Tacoma tideflats Area can be expected within the area with Universal
Transverse Mercator (UTM) X coordinates ranging from 537 to 552 kilometers
and UTM Y coordinates ranging from 5,230 to 5,242 kilometers. This appendix
gives the elevations in meters above mean sea level of receptors which
cover this area at 500-meter intervals in a Cartesian coordinate system.
Note that UTM X and Y coordinates in units of meters rather than in units
of kilometers are required for SHORTZ/LONGZ calculations.
B.-1
-------
TftSLE B-l.
UTM X
5370)0
5330)0
5330)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5450)0
547000
548000
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)0
5405)0
5415)0
5425)0
543500
54450)
5455)0
546500
5475)0
5435))
5495)0
55)5)0
5515)0
5370)0
5390)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5480)0
5490)0
SSOOOO
'JTrl Y
5230000
52300)0
5 1 3 ) >» O
3230000
5230000
52300)0
5230000
3230000
5230000
52300)0
5230000
52300)0
5230000
52300)0
52300)0
52300)0
32305)0
5230500
5230500
5230300
32305)0
5230500
5230300
52305)0
5230500
5230500
52305)0
32305)0
52305)0
5230500
5230500
52310)0
52310)0
52310)0
52310)0
5231000
52310)0
52310)0
5231000
3231000
52310)0
32310)0
52310)0
52310)0
52310)0
ELEV.
: 1ETE3? )
67
88
71
93
107
107
91
82
52
43
6
3
S
9
9
12
93
94
73
107
10t
101
91
83
61
37
S
5
6
6
9
7)
91
104
73
7S
73
67
83
21
3
S
S
S
S
IJTH X
5375)0
5335)0
5395)0
5405)0
5415)0
5425)0
5433)0
5445)0
5455)0
546500
5475)0
5485)0
5495)0
5505)0
5515)0
5370)0
5380)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5480)0
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)0
5405)0
5415)0
5425)0
5435)0
5445)0
5455)0
546500
5475)0
5485)0
5495)0
5505)0
UT« Y
52300)0
52300)0
5230O0
5230000
5230000
5230000
52300)0
5230000
5230000
52300)0
52300)0
52300)0
52300')0
32300)0
5230000
52305)0
32305)0
52305)0
5230500
3230500
32305)0
5230500
5230500
32305)0
52305)0
5230500
32305)0
32305)0
52305)0
52305)0
52305)0
32310)0
52310)0
32310)0
32310)0
52310)0
52310)0
32310)0
5231000
52310)0
32310)0
32310)0
52310)0
52310)0
32310)0
ELEV.
CKETE3S ?
73
91
91
104
107
104
67
85
67
52
3
S
S
9
9
64
94
85
94
1 10
104
61
91
30
12
5
S
$
6
S
83
83
94
93
7S
7S
73
82
73
37
5
«
S
S
0
B-2
-------
TABLE B-l.
UTH X
5510)0
5520)0
5375)0
5335)0
5395)0
5405)0
5415)0
5425))
5435)0
3445)0
5455)0
346300
3475)0
5435)0
5495)0
5305)0
5515)0
5370)0
5330)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5480)0
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)0
540500
5415)0
34250)
3435)0
544500
3455)0
5465)0
5475)0
5485))
UTfl Y
5231000
52310)0
52315)0
52313)0
5231500
52315)0
5231500
5231500
52315)0
3231300
5231500
5231500
3231500
5231300
3231500
52313)0
32315)0
3232000
3232000
52320)0
5232000
5232000
5232000
5232000
5232000
52320)0
5232000
5232000
52320)0
52320)0
5232000
32320)0
52320)0
52323)0
52323)0
32323)0
5232500
5232500
5232500
3232300
5232500
52325)0
5232500
5232500
5232500
ELEV.
: 1ETE33 )
S
94
94
83
104
US
107
52
34
27
24
s
f
0
S
s
53
91
1 10
122
110
1 19
107
9
6
S
0
6
S
s
S
18
91
94
119
1 19
119
113
37
5
3
3
3
6
3
UTM X
3515)0
5370)0
5390)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
3450)0
5460)0
5470)0
5430)0
5490)0
5300)0
3310)0
5520)0
5373)0
5335)0
5393)0
5405)0
5415)0
5425)0
543500
5445)0
5455)0
5465)0
5475)0
5485)0
5495)0
5505)0
5315)0
5370)0
5380)0
5390)0
5400)0
541000
5420)0
5430)0
5440)0
5450)0
3460)0
5470)0
5480)0
5490)0
UTM Y
• "JETER 3)
32310)0
32315)0
32315)0
32315)0
32315)0
32313)0
3231300
52315)0
52315)0
32313)0
5231500
5231500
32315)0
5231500
3231500
32315)0
32315)0
52320)0
52320)0
52320)0
32320)0
32320)0
52320)0
5232000
3232000
52320)0
32320)0
5232000
52320)0
52320)0
52320)0
52320)0
52325)0
52325)0
52325)0
32325)0
5232500
5232500
3232500
5232500
52325)0
32325)0
52325)0
52325)0
52325)0
ELEV.
67
79
33
1 13
110
110
107
2?
34
12
5
S
S
S
f
s
64
94
91
110
US
110
43
&
$
S
S
S
s
s
s
70
83
94
US
1 10
119
94
S
5
3
3
3
S
3
B-3
-------
UT.1 X
DETERS)
549550
550550
55155-)
537050
533050
539050
540000
541050
542055
543050
544000
545050
546050
547050
543050
549050
550050
551050
552050
537550
533555
539550
540550
5415)5
542550
543550
544505
5 4 5 5 5 0
546500
547555
543500
549550
550550
551550
537050
533050
539050
540000
541000
542050
543000
544000
545050
546050
547050
UTM Y
t v P T P 3 ^ \
s * t * t \ J ^
5232500
5232350
52325)0
3233000
5233000
5233050
5233000
5233000
5233050
3233-500
5233000
3233000
5233000
5233000
5233050
3233000
5233000
3233050
5233050
5233550
3233500
3233500
5233500
5233550
5233500
5233500
3233500
5233500
5233500
3233500
5233500
5233550
3233500
5233500
5234000
5234050
5234050
5234050
3234000
5234000
5234000
3234000
5234000
3234000
3J34050
ELEV.
3
o
61
91
1<51
119
113
116
91
$
g
3
3
3
3
3
67
.$
79
93
1 13
119
113
104
37
3
3
3
3
3
3
79
$
43
1 19
110
115
1 10
1 I-)
91
3
3
3
3
3
TABLE B-l.
UTM X
550050
551050
55205«)
537550
538550
539350
540550
541350
542550
543550
544550
545500
546500
547550
543500
549550
550550
551550
537050
533050
535050
540000
541050
542050
543050
544000
545000
546050
547000
549050
549050
550000
551050
552050
537550
538550
539500
540500
541500
542500
543500
544500
545300
546500
547550
UTH Y
5232550
52325)0
52325)0
5233050
3233050
3233050
5233050
1233050
32330)')
5233050
5233000
5233050
5233000
5233050
32330)0
5233050
.1233050
5233050
3233550
3233550
3233550
5233500
3233500
5233550
5233500
5233500
5233550
5233500
5233550
5233500
5233500
5233500
3233550
5233500
3234050
5234050
3234050
32340)0
32340)0
5234000
5234000
3234000
3234000
3234000
3234000
ELEV.
13
0
94
94
123
US
113
107
34
3
3
3
3
3
3
a
9
43
110
110
1 13
1 13
113
83
0
3
3
3
3
3
3
79
12
73
113
1 10
110
1 13
93
&
3
3
3
3
3
B-4
-------
TABLE B-l.
t/TH X
3430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5385)0
5395)0
540500
541500
5425)')
543500
344500
545500
546500
547500
348500
5495)0
5505)0
5515)0
3370)0
3330)0
5390)0
5400)0
3410)0
5420)0
5430)0
5440)0
3450)0
3460)0
3470)0
549000
5490)0
5500)0
551000
552000
537500
3395)0
5395)0
3405)0
3415)0
3425)0
5435)0
5445)0
545500
UTM Y
5234000
3234000
3234000
32340)0
32340)0
5234500
5234500
5234500
5234500
3234500
3234500
3234500
3234500
5234500
5234500
3234500
5234500
3234300
5234500
3234500
32350)0
52350)0
5235000
5235000
3235000
3235000
32350)0
5235000
5235000
3235000
5235000
5235000
5235000
3235000
3235000
3235000
32355)0
32335)0
5235500
32335)0
5235500
5235500
32335)0
5235500
3235300
ELEV.
3
37
49
21
49
1 13
1 13
107
107
91
0
3
3
3
3
3
3
122
24
70
1 19
11)
107
91
64
0
3
3
3
3
3
3
122
110
15
73
llo
101
91
21
0
0
0
3
3
UTM X
349300
5495)0
530500
5315)0
5370)0
5380)0
539000
540000
5410)0
542000
5430)0
544000
545000
5460)0
5470)0
5480)0
5490)0
5300)0
5310)0
3320)0
5375)0
5335)0
5395)0
540500
5415)0
5425)0
5435)0
544500
5453)0
5465)0
5475)0
548500
5495)0
5305)0
5515)0
5370)0
5380)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
UTM Y
5234000
32340)0
32340)0
32340)0
32345)0
5234500
52345)0
5234500
3234500
32345)0
5234500
3234500
3234500
5234500
5234500
5234500
5234500
5234500
5234500
5234500
32350)0
52350)0
52350)0
52350)0
52350)0
52350)0
.32350)0
5235000
52350)0
5235000
52350)0
52350)0
5235000
52350)0
52350)0
5235500
52355)0
52355)0
5235500
32355)0
52355)0
52355)0
32355)0
3235500
5235500
ELEV.
(METERS)
3
125
18
52
110
110
110
101
94
7S
0
3
3
3
3
3
58
73
24
64
122
107
98
6?
67
0
0
3
0
3
0
61
113
24
58
123
107
98
70
S
0
0
0
0
3
B-5
-------
TABLE B-l.
un x
: METE*; >
546500
5475)0
543500
5435)0
5505)0
5515)0
5370)0
5330)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5430)0
5430)0
5500)0
3510)0
5520)0
5375)0
5335)0
5395)0
5405)0
5415)0
5425)0
5435)0
544500
545500
5465)0
5475)0
5435)0
5495)0
550500
5515)0
5370)0
5330)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
UT.1 Y
5235500
52355)0
5235500
52353)0
5235500
52355)0
3236<))0
5236000
32360)0
5236000
5236000
3236000
52360)0
5236000
5236000
5236000
5236000
5236000
5236000
5236000
5236000
5236000
5236500
5236500
5236500
5236500
32365)0
5236500
5236500
52365)0
5236300
5236500
5236300
5236500
5236500
5236300
5236500
52370)0
32370)0
32370)0
5237000
32370)0
32370)0
52370)0
5237000
ELEV.
! "IETE35 >
3
73
122
122
55
24
131
101
85
3
0
0
0
0
3
0
37
67
123
93
55
73
93
91
0
0
0
0
o
0
24
37
125
125
1 10
73
53
83
85
0
0
)
)
0
0
UT« X
CSETE3S)
5470)0
5480)0
549000
5500)0
551000
5520)0
5375)0
538500
539500
5405)0
541500
5425)0
5435)0
544500
545500
546500
547500
543500
549500
550500
5515)0
5370)0
5380)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
545000
5460)0
5470)0
5430)0
549000
5500)0
5510)0
5520)0
537500
5395)0
5395)0
5405)0
5415)0
5425)0
5435)0
5443)0
UTJJ Y
52355)0
5235500
3235500
52355)0
52355)0
52355)0
32360)0
52360)0
32360)0
5236000
5236000
5236000
32360)0
5236000
5236000
5236000
32360)0
32360)0
3236000
3236000
52360)0
3236500
3236500
5236500
52365)0
3236500
32365)0
3236500
5236500
3236500
3236500
5236500
5236500
3236500
3236500
5236500
32365)0
52370)0
52370)0
52370)0
52370)0
32370)0
52370)0
52370)0
52370)0
ELEV.
0
61
125
ll'O
30
70
1 10
91
13
0
0
0
0
0
3
3
107
125
122
67
43
94
93
79
0
0
0
0
0
0
30
1 10
122
119
93
67
75
83
67
0
0
9
0
0
0
B-6
-------
UTJ1 X
5450)0
546000
5470)0
5490)0
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)-)
5405)0
5415)0
5425)0
5435)0
5445)0
5453)0
546500
5475)0
5495)0
5495)0
5505)0
5515)0
5370)0
5390)0
5390)0
5400)0
5410)0
5420)0
5430)0
544000
5450)0
5460)0
547000
543000
5490)0
5300)0
5510)0
5520)0
3375)0
5335)0
5395)0
5405)0
5413)0
542500
UTK Y
: 1ETES5)
3237000
5237000
5237000
5237000
52370)0
52370)0
52370)0
5237000
5237500
32375)0
32375)0
5237500
5237500
5237500
32373)0
3237500
5237500
3237500
52375)0
5237500
5237500
5237300
5237500
32330)0
52330)0
52330)0
52330)0
5233000
5239000
5233000
3233')00
5233000
52390)0
5238000
3233000
5233000
3233000
5233440
5233000
32335)0
3233500
52393)0
5233300
5233300
5239500
TABLE B-l.
ELEV. UTfl X
24
85
13?
134
US
11)
61
73
73
)
0
0
0
0
0
0
113
119
131
11)
125
82
82
43
0
)
0
0
4
0
0
122
93
122
122
US
7*
91
101
S
3
0
0
0
30
5455)0
5463)0
5475)0
5495)0
5495)0
5505)0
5515)0
5370)0
5330)0
5390)0
5400)-)
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5430)0
.5490)0
5500)0
5310)0
5520)0
537500
5385)0
5395)0
5405)0
5413)0
5425)0
5435)0
544500
5455)0
5465)0
5475)0
5435)0
5495)0
5305)0
5515)0
5370)0
3380)0
5390)0
3400)0
5410)0
5420)0
5430)0
'JT,1 Y
DETERS)
32370)0
3237000
32370)0
52370)0
52370)0
32370)0
32370)0
52375)0
5237500
32375)0
52375)0
52375)0
5237500
52375)0
52375)0
3237500
52375)0
3237500
52375)0
52375)0
52375)0
52375)0
5237500
52330)0
52380)0
52380)0
52330)0
52380)0
52330)0
52380)0
32330)0
5238000
5239444
52380)0
5238000
52380)0
5233000
52380)0
32385)0
52385)4
52385)4
32383)0
32385)0
52335)0
32335)0
ELEV.
CMETE3S)
101
119
129
in
113
64
70
67
61
0
0
0
0
0
0
122
93
123
134
122
21S
70
88
37
0
0
0
0
0
0
67
123
110
123
10?
US
83
85
34
0
)
0
0
0
67
B-7
-------
TABLE B-l.
UT?I X
5435)0
5445)0
5455)0
5465)0
5475)0
5435)0
5495)0
5505)0
5515)0
5370)0
5330)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
3430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)0
5403)0
5415)0
5425)0
543500
544500
5455)0
546500
5475)0
5435)0
5435)0
5505)0
5515)0
5370)0
5330)0
3390)0
5400)0
5410)0
UT* Y
5233500
3233500
5233500
5233500
5233500
523S500
5233500
5233500
5233500
52390)0
52330)0
52390)0
52390)0
52390)0
52390)0
32390)0
3239000
52390)0
3239000
32390)0
52390)0
32390)0
52390)0
52390)0
52390)0
523')3)0
52395)0
52395)0
52395)0
5239500
5239500
5239500
5239500
52395)0
52395)0
5239500
52395)0
32395)0
52395)0
3239500
5240000
52400)0
5240000
5240000
5240000
ELEV.
104
123
14)
101
119
10*
91
107
91
0
0
)
0
0
0
58
137
134
104
125
101
94
122
104
113
)
)
0
0
0
0
us
119
91
98
83
104
101
113
122
0
0
)
0
0
UTfl X
CHETE^S)
5440)0
5450)0
5460)0
5470)0
5430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5385)0
5395)0
5405)0
5415)0
5425)0
5435)0
544500
5455)0
5465)0
547500
5485)0
5493)0
5305)0
5515)0
5370)0
5330)0
5390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450)0
5460)0
5470)0
5430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5335)0
5395)0
540500
541500
UTfl Y
5233500
3233500
52395*0
12395)0
5238500
5233500
5233500
52335)0
5238500
52390)0
52390>0
52390)0
52390)0
52390)0
52390)0
52390)0
3239000
32390)0
52390)0
32390)0
52390)0
32390)0
32390)0
32390)0
52393)0
32395)0
52395)0
52395)0
52395)0
52395)0
52395)0
52395)0
52395)0
3239500
52395)0
32395)0
52395)0
52395)0
32395)0
52395)0
52400)0
52400)0
52400)0
5240000
3240000
ELEV
110
140
110
122
110
10?
101
94
101
0
9
9
0
9
21
98
165
140
110
98
98
91
94
119
0
9
9
0
0
0
12
131
104
79
91
83
94
123
1 1 S
122
0
0
0
Q
0
-------
UT.1 X
5420)0
5430)0
5440)0
3450')0
5460)0
5470)0
5430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5385)0
5395)0
5405)0
541500
5425)0
5435)0
344500
5455)0
5465)0
5475)0
5435)0
5495)0
5505)0
5515)0
3370)0
3380)0
3390)0
5400)0
5410)0
5420)0
5430)0
5440)0
5450*0
546090
5470)0
5480)0
5490)0
5300)0
5510)0
5520)0
3375)0
3385)0
3395)0
'JTM Y
5240000
52400)0
32400)0
5240000
5240000
5240000
5240000
52400)0
32400)0
52400)0
52400)0
5240500
5240500
5240500
5240500
52405)0
5240500
5240500
3240500
5240500
5240500
5240500
5240500
52405)0
5240500
5240500
52410)0
52410)0
52410)0
5241000
32410)0
5241000
5241000
32410)0
5241000
3241000
5241000
5241000
32410)0
5241000
5241000
52410)0
5241500
5241500
52413)0
TABLE B-l.
ELEV. UTM X
0
0
83
53
73
67
82
91
104
IIS
122
0
0
0
0
0
0
24
21
73
79
73
85
94
113
134
)
0
0
0
0
0
0
0
0
55
34
43
91
93
134
14)
)
0
0
3425)0
5435)0
5445)0
5455)0
545500
5475)0
5485)0
5495)0
5503)0
5515)0
5370)0
5380)0
5390)0
3400)0
5410)0
5420)0
5430)0
5440)0
5450*0
5460<)0
5470)0
5430)0
5490)0
5500)0
5510)0
5520)0
5375)0
5385)0
5393)0
5403)0
5415)0
5425)0
5433)0
5445)0
5455)0
5463)0
5475)0
5435)0
5495)0
5303)0
5315)0
5370)0
5380)0
5390)0
5400)0
IJTM Y
• "IETE33 )
3240000
5240000
32400)0
3240000
5240000
5240000
52400)0
52400')0
5240000
32400)0
52403)0
52405)0
32405)0
5240500
32405)0
52405-)0
5240500
5240500
3240500
5240500
3240500
5240500
52405<>0
52405)0
5240500
5240500
32410)0
52410)0
32410)0
3241000
52410)0
52410)0
3241000
32410)0
52410)0
5241000
52410)0
5241000
5241000
32410)0
32410)0
52415)0
32415)0
52415)0
32415)0
ELEV.
(METERS)
0
113
49
7S
6?
73
101
93
110
134
0
0
0
0
0
0
0
43
67
5?
79
6?
85
91
125
131
0
0
0
0
0
0
0
0
61
49
70
61
98
104
134
0
0
0
0
B-9
-------
TABLE B-l.
UTfl X
: NETER; )
540500
541500
542500
543500
544500
545500
546500
547500
549500
549500
550500
551500
537000
538000
539000
540000
541000
542000
543000
544000
545000
546000
547000
548000
549000
550000
551000
552000
'JTK Y
C DETERS)
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241300
5241500
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
ELEV.
0
0
0
0
0
0
£
40
88
93
104
131
0
55
0
0
0
0
0
0
0
0
0
82
104
107
104
146
UTM X
( SETE^S)
541000
5420)0
5430)0
5440)0
5450)0
5460)0
547000
5480)0
5490)0
550000
551000
552000
537500
538500
539500
540500
541500
542500
543500
544500
545500
546500
547500
548500
549500
550500
551500
UTft Y
5241500
3241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5241500
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5242000
5 1 42 000
5242000
5242000
5242000
5242000
5242000
ELEV.
(HETE3S)
0
0
0
0
0
49
0
91
93
93
131
143
30
9
0
0
0
0
0
0
0
0
15
79
107
113
137
B-LO
-------
APPENDIX C
PRELIMINARY SHORTZ AND LONGZ METEOROLOGICAL INPUTS
Table C-l lists in chronological order the SHORTZ hourly meteor-
ological inputs for the 23 "worst case" 3-hour periods discussed in Sec-
tion 5.1. Similarly, Table C-2 lists in chronological order the SHORTZ
hourly meteorological inputs for the 14 "worst case" 24-hour periods dis-
cussed in Section 5.1. The annual wind summary (STAR summary) suggested in
Section 5.2 for use with LONGZ is given in Table C-3.
C-l
-------
TABLE C-l
SHORTZ 3-HOUR METEOROLOGICAL INPUTS
HOUR
(PST)
WIND
DIR.
(DEC)
WIND
SPEED
(MPS)
MIXING
DEPTH
(M)
AMB.
TEMP
(DEC
K)
POT.
TEMP
(DEC K/M)
STAB
CAT.
WIND
EXP.
STD DEV.
EL ANGLE
(RAD)
STD DEV.
AZ ANGLE
(RAD)
16 FEBRUARY 1981
20 217 7.60 875 285 .003 D .10 .0465
21 217 6.30 875 286 .003 D .10 .0465
22 217 5.90 875 286 .003 D .10 .0465
17 FEBRUARY 1981
2 229 5.20 875 285 .003 D .10 .0465
3 228 5.10 690 286 .005 D .15 .0465
4 229 4.70 690 286 .005 D .15 .0465
29 MARCH 1981
8 224 6.20 875 285 .003 D .10 .0465
9 222 6.60 875 284 .003 D .10 .0465
10 224 6.90 875 283 .003 D .10 .0465
29 MARCH 1981
12 230 6.50 875 283 .003 D .10 .0465
13 231 6.70 875 283 .003 D .10 .0465
14 230 6.70 875 283 .003 D .10 .0465
30 MARCH 1981
9 212 4.40 690 280 .005 D .15 .0465
10 212 4.70 690 280 .005 D .15 .0465
11 213 4.70 690 280 .005 D .15 .0465
31 MARCH 1981
6 185 4.60 690 283 .005 D .15 .0465
7 184 4.20 690 283 .005 D .15 .0465
8 185 3.70 690 282 .005 D .15 .0465
5 APRIL 1981
17 245 6.70 875 284 .003 D .10 .0465
18 247 6.50 875 284 .003 D .10 .0465
19 246 6.20 875 284 .003 D .10 .0465
.0665
.0665
,0665
.0665
.0665
,0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
,0665
.0665
,0665
.0665
.0665
.0665
.0665
.0665
C-2
-------
TABLE C-l (Continued)
HOUR WIND
(PST) DIR.
(DEC)
WIND
SPEED
(MPS)
MIXING AMB.
DEPTH
(M)
TEMP
(DEC
K)
POT. STAB
TEMP CAT.
(DEC
K/M)
WIND STD DEV.
EXP. EL ANGLE
(RAD)
STD DEV.
AZ ANGLE
(RAD)
21 APRIL 1981
13 237 3.50 690 282 .005 D .15 .0465 .0665
14 237 4.20 690 281 .005 D .15 .0465 .0665
15 237 4.30 690 281 .005 D .15 .0465 .0665
22 APRIL 1981
4 216 4.20 690 286 .005 D .15 .0465 .0665
5 217 4.80 690 286 .005 D .15 .0465 >0665
6 216 4.60 690 287 .005 D .15 .0465 .0665
7
8
9
23
24
1
8
9
10
15
16
17
214
214
213
235
236
236
222
220
222
223
222
223
212
211
212
21 MAY 1981
4.20 690 288 .005 D .15 .0465 .0665
4.40 690 289 .005 D ,15 .0465 .0665
4.10 690 287 .005 D .15 »0465 .0665
30 MAY 1981
2.10 250 290 .020 E .25 .0350 .0501
2.10 250 295 .020 E ,25 .0350 =0501
2.40 250 296 .020 E .25 .0350 .0501
13-14 JUNE 1981
2.20 250 284 .020 E .25 .0350 .0501
2.10 250 285 .020 E .25 .0350 ,0501
2.00 250 287 .020 E .25 .0350 ,0501
17 JUNE 1981
4.60 690 288 .005 D .15 .0465 ,0665
4.70 690 288 .005 D .15 .0465 ,0665
5.00 690 287 .005 D .15 .0465 =0665
18 JUNE 1981
3.60 690 284 .005 D ,15 o0465 ,0665
4.90 690 284 .005 D .15 .0465 ,0665
5.50 875 283 .003 D .10 .0465 .0665
C-3
-------
TABLE C-l (Continued)
HOUR
(PST)
WIND
DIR.
(DEC)
WIND
SPEED
(MPS)
MIXING
DEPTH
(M)
AMB.
TEMP
(DEC
K)
POT.
TEMP
(DEC K/M)
STAB
CAT.
WIND
EXP.
STD DEV.
EL ANGLE
(RAD)
STD DEV.
AZ ANGLE
(RAD)
24
1
2
36
39
37
1.50
2.00
1.90
26-27 JULY 1981
125
250
250
293
296
298
.030
.020
.020
E
E
E
,30
,25
,25
.0350
,0350
,0350
,0501
,0501
,0501
27-28 JULY 1981
23
24
1
2
3
4
23
24
1
234
234
232
52
52
51
227
228
227
47
50
49
2.10
2.50
2.50
1.40
1.60
1.70
2.30
2.50
2.00
2.10
2.40
1.50
250
250
250
125
250
250
250
250
250
250
250
125
291
295
296
.020
.020
.020
9 AUGUST 1981
299
300
301
.030
.020
.020
24 AUGUST 1981
295
296
297
.020
.020
.020
25-26 AUGUST 1981
288
289
291
.020
.020
.030
1 SEPTEMBER 1981
E
E
E
E
E
E
E
E
E
E
E
E
,25
,25
,25
,30
,25
,25
,25
,25
,25
.25
.25
,30
.0350
,0350
,0350
.0350
.0350
.0350
.0350
,0350
.0350
.0350
.0350
.0350
,0501
,0501
,0501
.0501
.0501
.0501
.0501
.0501
,0501
,0501
.0501
,0501
11
12
13
225
224
224
5.60
5.00
4.90
875
690
690
290
289
289
.020
.020
.020
D
D
D
.10
.15
.15
.0465
.0465
.0465
.0665
.0665
.0665
C-4
-------
TABLE C-l (Continued)
HOUR WIND WIND MIXING AMB. POT. STAB WIND STD DEV. STD DEV.
(PST) DIR. SPEED DEPTH TEMP TEMP CAT. EXP. EL ANGLE AZ ANGLE
(DEC) (MPS) (M) (DEC K) (DEC K/M) (RAD) (RAD)
25 SEPTEMBER 1981
19
20
21
19
20
21
20
21
22
57
59
56
227
225
226
205
206
208
1.40
1.50
1.80
2.50
2.00
2.10
2.50
2.10
2.00
125
125
250
250
250
250
250
250
250
283
283
282
.030
.030
.020
2 OCTOBER 1981
283
283
283
.020
.020
.020
25 DECEMBER 1981
277
276
278
.020
.020
.020
E
E
E
E
E
E
E
E
E
,30
,30
,25
,25
,25
,25
.25
.25
.25
.0350
.0350
,0350
.0350
.0350
.0350
.0350
.0350
.0350
.0501
.0501
.0501
.0501
.0501
.0501
.0501
.0501
,0501
C-5
-------
TABLE C-2
SHORTZ 24-HOUR METEOROLOGICAL INPUTS
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
211
208
194
196
204
206
218
223
228
229
225
229
228
208
209
213
228
224
221
214
223
221
212
182
209
200
210
221
221
216
219
213
211
214
217
217
217
222
226
2.30
2.60
2.30
2.40
2.30
2.90
3.30
3.30
3.50
3.30
3.30
3.30
2.80
2.20
2.50
2.20
3.00
3.50
3.30
3.60
3.50
3.40
2.10
1.80
4.60
4.40
5.50
5.90
6.30
6.90
6.70
6.70
7.10
8.20
7.60
6.30
5.90
5.70
4.90
595
595
595
595
595
595
690
690
690
690
690
690
595
595
595
595
595
690
690
690
690
690
250
250
690
690
875
875
875
875
875
875
875
875
875
875
875
875
690
23-24
281
281
281
281
281
281
281
281
282
282
282
282
281
281
281
281
282
280
280
279
279
279
279
278
16-17
284
284
283
283
283
283
283
283
283
285
285
286
286
286
285
JANUARY ]
.010
.010
.010
.010
.010
.010
.005
.005
.005
.005
.005
.005
.010
.010
.010
.010
.010
.005
.005
.005
.005
.005
.020
.020
FEBRUARY
.005
.005
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.005
L981
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
E
E
1981
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
.20
.20
.20
.20
.20
.20
.15
.15
.15
.15
.15
.15
.20
.20
.20
.20
.20
.15
.15
.15
.15
.15
.25
.25
.15
.15
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.15
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0350
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0455
.0465
.0465
.0465
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0501
.0501
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.Oh 65
.0665
.0665
.0665
C-6
-------
TABLE C-2 (Continued)
HOUR
(PST)
1
2
3
4
5
6
7
8
9
WIND
DIR.
(DEC)
234
229
228
229
225
212
214
219
212
WIND
SPEED
(MPS)
5.10
5.20
5.10
4.70
4.50
3.70
3.70
3.80
4.10
MIXING
DEPTH
(M)
690
875
690
690
690
690
690
690
690
AMB.
TEMP
(DEC K)
285
285
286
286
287
286
285
284
283
POT.
TEMP
(DEC K/M)
.005
.003
.005
.005
.005
.005
.005
.005
.005
STAB
CAT.
D
D
D
D
D
D
D
D
D
WIND
EXP.
.15
.10
.15
.15
.15
.15
.15
.15
.15
STD DEV.
EL ANGLE
(RAD)
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
STD DEV.
AZ ANGLE
(RAD)
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
29-30 MARCH 1981
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1
2
3
4
5
224
217
224
222
224
236
230
231
230
227
229
224
221
218
221
225
234
238
234
230
229
223
220
224
7.80
7.00
6.20
6.50
6.90
6.60
6.50
6.70
6.70
6.70
7.00
6.30
6.50
6.90
6.30
6.00
5.30
5.60
5.50
5.40
5.30
5.20
5=60
6.10
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
875
285
285
285
287
283
283
283
283
283
282
281
281
281
282
283
281
280
280
280
280
281
281
281
281
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
.003
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0665
.0665
.0665
.0665
.0665
-0665
.0665
,0665
.0665
.0665
.0665
,0665
.0665
.0665
.0665
.0665
.0665
.0665
,0665
.0665
.0665
.0665
= 0665
o0665
6
7
8
9
10
220
214
217
212
212
5.80
4.50
4.40
4.40
4.70
875
690
690
690
690
30-31 MARCH 1981
281 .003
281 .005
281 .005
280 .005
280 .005
D
D
D
D
D
.10
.15
.15
.15
.15
.0465
.0465
.0465
.0465
.0465
.0665
.0665
.0665
.0665
.0665
C-7
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1
2
3
4
5
213
210
212
218
212
205
194
203
199
208
203
203
187
195
201
199
202
208
194
4.70
4.90
5.30
5.50
5.40
5.70
5.20
4.70
4.70
4.20
4.20
4.70
4.20
5.00
4.60
5.00
4.30
4.70
4.70
690
690
1000
875
1000
875
875
690
690
690
440
690
690
690
690
690
690
690
690
280
280
280
279
279
279
279
279
279
279
279
279
279
279
280
280
281
281
282
.005
.005
0.000
.003
0.000
.003
.003
.005
.005
.005
.015
.005
.005
.005
.005
.005
.005
.005
.005
D
D
C
D
C
D
D
D
D
D
E
D
D
D
D
D
D
D
D
.15
.15
.10
.10
.10
.10
.10
.15
.15
.15
.20
.15
.15
.15
.15
.15
.15
.15
.15
.0465
.0465
.0735
.0465
.0735
.0465
.0465
.0465
.0465
.0465
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0665
.0665
.1051
.0665
.1051
.0665
.0665
.0665
.0665
.0665
.0501
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
8-9 APRIL 1981
15
16
17
18
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
221
222
216
224
230
228
224
218
221
221
286
212
211
214
218
214
217
222
221
219
211
229
5.30
5.00
5.60
5.60
5.40
5.80
5.20
4.80
4.90
5.10
4.20
5.00
5.60
5.70
5.60
5.40
4.70
4.60
5.80
5.90
6.20
4.60
875
690
875
875
875
875
875
690
690
690
690
690
875
875
875
875
690
690
875
875
1000
940
280
280
279
279
279
279
279
279
279
280
280
280
281
281
283
282
281
280
280
280
280
279
.003
.005
.003
.003
.003
.003
.003
.005
.005
.005
.005
.005
.003
.003
.003
.003
.005
.005
.003
.003
0.000
0.000
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
B
C
.10
.15
.10
.10
.10
.10
.10
.15
.15
.15
.15
.15
.10
.10
.10
.10
.15
.15
.10
.10
.10
.10
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.1080
.0735
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.1544
.1051
CO
— O
-------
TABLE C-2 (Continued)
HOUR
(PST)
13
14
WIND
DIR.
(DEC)
230
226
WIND
SPEED
(MPS)
4.50
4.60
MIXING
DEPTH
(M)
940
940
AMB.
TEMP
(DEC K)
278
278
POT.
TEMP
(DEC K/M)
0.000
0.000
STAB
CAT.
C
C
WIND
EXP.
.10
.10
STD DEV.
EL ANGLE
(RAD)
.0735
.0735
STD DEV.
AZ ANGLE
(RAD)
.1051
.1051
21-22 APRIL 1981
16
17
18
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
231
229
212
218
215
211
221
234
229
219
215
215
216
217
216
219
220
218
228
228
226
226
228
231
4.50
3.80
3.50
3.40
4.10
3.80
3.00
2.70
2.80
3.60
3.70
4.00
4.20
4.80
4.60
4.50
4.40
5.20
4.60
5.40
5.70
5.20
4.30
4.10
690
690
690
690
690
440
250
595
595
690
690
690
690
690
690
690
690
875
690
875
875
1000
940
690
281
280
280
280
280
280
280
281
283
284
285
285
286
286
287
287
287
286
285
285
285
285
284
284
.005
.005
.005
.005
.005
.015
.020
.010
.010
.005
.005
.005
= 005
.005
.005
.005
.005
.003
.005
.003
.003
0.000
0.000
.005
D
D
D
D
D
E
E
D
D
D
D
D
D
D
D
D
D
D
D
D
D
C
C
D
.15
.15
.15
.15
.15
.20
.25
.20
.20
.15
.15
.15
.15
,15
.15
.15
.15
.10
.15
.10
.10
.10
.10
.15
.0465
.0465
.0465
.0465
.0465
.0350
.0350
.0465
.0465
.0465
.0465
.0465
o0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0735
.0735
.0465
.0665
.0665
.0665
.0665
.0665
.0501
.0501
.0665
.0665
.0665
.0665
.0665
,0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.1051
.1051
.0665
1-2 MAY 1981
11
12
13
14
15
16
17
18
19
20
21
22
224
209
214
205
214
220
216
248
237
222
227
232
4.00
4.20
4,70
4.30
4.40
4.50
4.00
3.20
3.70
3.80
3.40
3.20
940
690
690
690
940
690
690
690
440
440
440
440
288
287
286
285
284
283
282
281
281
280
280
281
0.000
.005
.005
.005
0,000
.005
.005
.005
.015
.015
.015
.015
C
D
D
D
C
D
D
D
E
E
E
E
.10
.15
.15
.15
.10
.15
.15
.15
.20
.20
.20
.20
.0735
,0465
.0465
.0465
.0735
.0465
.0465
.0465
.0350
.0350
.0350
.0350
.1051
.0665
.0665
.0665
.1051
.0665
.0665
.0665
.0501
.0501
.0501
.0501
C-9
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
23
24
1
2
3
4
5
6
7
8
9
10
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1
2
1
2
213
208
211
216
212
213
209
206
215
213
219
222
230
227
223
222
222
217
233
233
240
243
242
232
231
239
245
251
243
241
242
237
239
237
234
235
234
251
3.80
3.60
3.90
4.00
3.80
3.90
3.90
4.10
3.90
4.90
5.20
5.10
1.70
1.90
2.30
2.60
2.50
2.40
2.60
2.60
2.60
2.50
2.40
2.80
3.30
3.00
3.40
3.50
3.30
3.40
3.80
3.50
4.00
2.80
2.80
3.70
2.00
1.70
440
440
690
690
690
690
690
690
690
690
1000
690
595
595
595
595
595
595
595
595
595
595
595
595
690
595
690
690
690
440
440
690
690
690
690
690
595
595
281
283
285
284
284
284
284
284
285
285
285
284
20-21
284
285
285
285
286
287
287
286
286
286
286
285
285
285
284
284
284
284
284
284
284
284
285
285
25
289
290
.015
.015
.005
.005
.005
.005
.005
.005
.005
.005
0.000
.005
MAY 1981
.010
.010
.010
.010
.010
.010
.010
.010
.010
.010
.010
.010
.005
.010
.005
.005
.005
.015
.015
.005
.005
.005
.005
.005
MAY 1981
.010
.010
E
E
D
D
D
D
D
D
D
D
B
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
E
E
D
D
D
D
D
D
D
.20
.20
.15
.15
.15
.15
.15
.15
.15
.15
.10
.15
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.20
.15
.20
.15
.15
.15
.20
.20
.15
.15
.20
.20
.15
.20
.20
.0350
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.1080
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0350
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0501
.0501
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.1544
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0501
.0501
.0665
.0665
.0665
.0665
.0665
.0665
.0665
C-10
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
19
20
21
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
247
233
228
229
231
237
236
244
249
234
239
234
243
247
250
245
248
236
238
211
204
230
244
227
237
210
227
231
237
237
223
208
193
208
219
233
228
219
221
229
232
1.70
1.80
2.00
2.10
2.70
3.30
3.20
3.80
4.40
4.90
4.20
4.00
3.80
4.40
4.20
3.30
2.90
2.30
2.30
1.90
1.80
1.60
3.30
3.50
3.50
4.50
4.50
4.20
4.60
4.00
3.90
2.90
1.90
2.90
3.40
3.20
4.20
4.20
3.80
3.50
3.30
250
595
595
940
595
690
690
690
690
690
690
690
690
690
690
690
595
595
595
595
595
595
690
690
690
690
690
690
690
690
690
595
595
595
690
690
690
690
690
690
940
290
290
290
291
290
290
289
289
288
288
286
286
286
286
286
286
286
286
286
286
286
286
5-6
285
285
285
286
286
287
288
289
292
293
291
290
289
289
290
288
288
288
286
.020
.010
.010
0.000
.010
.005
.005
.005
.005
.005
.005
.005
.005
.005
.005
.005
.010
.010
.010
.010
.010
.010
JUNE 1981
.005
.005
.005
.005
.005
.005
.005
.005
.005
.010
.010
.010
.005
.005
.005
.005
.005
.005
0.000
E
D
D
C
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
B
.25
.20
.20
.15
.20
.15
.15
.15
.15
.15
.15
.15
.15
.15
.15
.15
.20
,20
,20
,20
.20
.20
.15
.15
.15
.15
.15
.15
.15
.15
.15
.20
.20
.20
.15
.15
.15
.15
.15
.15
.10
.0350
.0465
.0465
.0735
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
,0465
.0465
.0465
,0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.1080
.0501
.0665
.0665
.1051
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.1544
C-ll
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
14
15
16
17
18
237
238
241
235
249
3.30
3.60
3.10
2.90
2.80
690
940
940
940
940
286
284
284
283
283
.005
0.000
0.000
0.000
0.000
D
B
B
B
C
.15
.10
.10
.10
.15
.0465
.1080
.1080
.1080
.0735
.0665
.1544
.1544
.1544
.1051
6-7 JULY 1981
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
221
210
216
222
226
226
224
223
217
220
223
227
228
226
233
225
227
239
236
239
234
232
229
227
3.40
3.40
3.10
3.20
3.80
4.00
4.20
4.50
5.70
5.90
6.70
6.40
6.40
6.30
6.00
6.30
5.50
5.50
5.20
5.50
4.30
4.00
3.90
3.90
690
690
595
690
690
690
690
690
875
875
875
875
1000
1000
1000
1000
1000
1000
1000
1000
690
440
690
690
284
285
286
286
286
289
289
289
289
286
288
288
287
286
285
284
283
282
283
283
283
283
283
283
.005
.005
.010
.005
.005
.005
.005
.005
.003
.003
.003
.003
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
.005
.015
.005
.005
D
D
D
D
D
D
D
D
D
D
D
D
C
B
B
C
B
B
C
C
D
E
D
D
.15
.15
.15
.15
.15
.15
.15
.15
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.10
.15
.20
.15
.15
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0735
.1080
.1080
.0735
.1080
.1080
.0735
.0735
.0465
.0350
.0465
.0465
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.1051
.1544
.1544
.1051
.1544
.1544
.1051
.1051
.0665
.0501
.0665
.0665
21-22 JULY 1981
7
8
9
10
11
12
13
14
15
240
241
243
258
258
251
223
251
257
2.30
2.00
2.10
2.00
1.30
2.50
3.20
3.70
3.50
595
595
595
595
500
595
690
690
690
293
292
291
290
290
289
289
288
288
.010
.010
.010
.010
.015
.010
.005
.005
.005
D
D
D
D
D
D
D
D
D
.20
.20
.20
.20
.25
.20
.15
.15
.15
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
C-12
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
16
17
18
19
20
21
22
23
24
1
2
3
4
5
6
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1
2
3
247
250
254
252
244
242
255
259
246
235
223
231
240
244
237
218
210
194
194
184
193
213
213
209
209
218
214
210
209
201
200
213
203
192
190
213
211
204
205
3.10
3.10
3.20
3.00
2.60
2.60
2.50
2.80
2.50
2.20
2.10
1.90
1.90
1.70
1.90
2.30
2.20
2.40
2.00
2.10
1.90
2.40
3.20
3.80
3.80
3.90
3.50
3.40
3.40
2.90
2.60
2,90
2,80
2.20
2.10
1.50
2.10
2.10
1.70
595
595
690
595
595
595
595
595
595
595
250
595
250
250
940
595
250
595
595
595
595
595
690
690
690
940
940
690
690
595
595
595
595
595
595
500
250
595
595
288
288
287
286
287
286
287
288
288
288
289
290
291
292
291
29-30
286
286
286
284
284
283
282
283
283
282
281
282
282
282
281
281
281
281
280
280
281
281
283
283
.010
.010
.005
.010
.010
.010
.010
.010
.010
.010
.020
.010
.020
.020
0.000
OCTOBER 1981
.010
.020
.010
.010
.010
.010
.010
.005
.005
.005
0.000
0.000
.005
.005
.010
.010
.010
.010
.010
,010
.015
.020
.010
.010
D
D
D
D
D
D
D
D
D
D
E
D
E
E
C
D
E
D
D
D
D
D
D
D
D
C
C
D
D
D
D
D
D
D
D
D
E
D
D
.15
.15
. 15
.20
.20
.20
.20
.20
.20
.20
.25
.20
.25
.25
.15
,20
,25
,20
.20
.20
.20
.20
.15
.15
.15
.10
.10
.15
.15
.20
.20
.20
.20
.20
.20
.25
.25
.20
.20
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0350
.0465
.0350
.0350
.0735
,0465
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0735
.0735
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0350
.0465
.0465
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0501
.0665
.0501
.0501
.1051
.0665
.0501
.0665
,0665
.0665
.0665
.0665
.0665
.0665
.0665
.1051
.1051
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0501
.0665
.0665
C-13
-------
TABLE C-2 (Continued)
HOUR WIND WIND MIXING AMB. POT.
(PST) DIR. SPEED DEPTH TEMP TEMP
(DEC) (MPS) (M) (DEC K) (DEC K/M)
STAB WIND STD DEV. STD DEV.
CAT. EXP. EL ANGLE AZ ANGLE
(RAD) (RAD)
9-10 DECEMBER 1981
22
23
24
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
204
214
214
206
191
192
195
188
192
195
191
188
209
197
191
200
203
207
210
206
216
204
208
214
4.30
5.50
5.40
5.50
5.00
5.90
5.80
4.70
5.20
5.90
5.20
5.00
3.80
4.00
5.10
4.70
5.30
4.40
4.10
4.10
3.40
3.00
3.60
3.40
440
440
875
875
440
440
875
690
875
875
875
690
690
690
690
690
875
690
690
690
690
595
690
690
280
279
280
280
281
282
282
283
284
284
284
284
284
283
283
284
283
283
282
281
281
280
280
280
.015
.015
.003
.003
.015
.015
.003
.005
.003
.003
.003
.005
.005
.005
.005
.005
.003
.005
.005
.005
.005
.010
.005
.005
E
E
D
D
E
E
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
.20
.15
.10
.10
.20
.15
.10
.15
.10
.10
.10
.15
.15
.15
.15
.15
.10
.15
.15
.15
.15
.20
.15
.15
.0350
.0350
.0465
.0465
.0350
.0350
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0465
.0501
.0501
.0665
.0665
.0501
.0501
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
,0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
.0665
C-14
-------
TABLE C-3
1972 ANNUAL JOINT FREQUENCY OF OCCURRENCE AT THE PSAPCA N26th & PEARL SITE
OF WIND-SPEED AND WIND-DIRECTION CATEGORIES, CLASSIFIED ACCORDING
TO THE PASQUILL STABILITY CATEGORIES
STABILITY CATEGORY A
STABILITY CATEGORY B
STABI11 TY CATEGORY c
n
DIRECTION
(SECTOR )
N
HNE
HE
EHE
E
ESE
SE
SSE
S
SSy
SV
ysv
y
VNV
NV
NNV
TOTAL
yiHD
0-1.5
. 6000
. 0000
. 0004
0004
. 0000
0000
.0000
0000
. 0000
0001
. 0000
.0001
.0004
. 0002
0002
0003
0026
SP-ED M/SEO
1.6-3.0 »«»*•
.0000
. 4005
. 0002
. 0000
. 4000
. JOOO
.9000
.0000
.0000
.0000
.0002
. 0002
.0002
.0001
.0000
.0000
. )OU
1 U 1 1 L
.00)0
.00)3
.0049
.90)4
.00)0
.00)0
.00)0
.00)0
00)0
.00)1
.90)2
. 00)4
00)4
.00)4
.00)2
.00)3
.0042
WIND S'EED ; I/SEC)
» 1 . 3
.0013
.0)42
.0052
.0024
0014
.0041
. 0400
.0444
.04)3
.0010
. 041 3
.0»17
.0011
.0028
.0012
.0023
. 0344
.0017
. 003)
.004)
.0012
000 >
. 000)
. 000)
. 0001
. 0001
.000)
. 001 )
. 004«
. 002)
.000]
. 0002
. 0002
. 0224
•>OI4
>033
. 4030
. 0040
0000
0000
•)000
0000
<>000
•>040
0016
4021
. 0003
. 0000
. 0000
0000
. >) 1 2 1
* n f A i
T 0 1 H L
.0)48
0124
0131
0034
OOOi
0501
0300
0)03
.0)04
0010
.0)40
0102
0085
.0033
. 0033
0024
. 0«» 1
0032
0023
0044
0024
0010
0004
0005
0011
0012
0012
0030
0027
.0024
0016
.0011
0012
.02)8
. 0020
.0042
405 9
)OI 7
4 0 •) I
>0> 1
40)0
00)4
> 0 1 •>
) * 1 •>
)033
)018
.0013
') 0 4 4
40 )4
4001
0 ?9 1
yiHO SPEED < fl/SEC >
0037
0131
C>079
coo;
0001
0000
0000
0001
0004
00 1 1
0044
0041
0005
0001
0000
0001
C>353
V . « 7 I
00)4
.0032
00)7
.00)0
•><>)0
0040
0000
.00)0
oo>o
00)1
.00)4
00)1
.00)0
.00)0
00)0
0040
0052
0 > - 1 9 8
0<)00
0000
0000
oooo
0000
0000
0000
.0000
0000
0000
0 •>(• 0
0000
0000
0000
0000
0000
0000
>10 .8
0000
0000
0000
0000
0000
0000
0000
OOOd
0000
0000
0000
0000
0000
0000
. 0000
0000
0000
TOTAL
. 0095
0230
0201
0039
00 12
ooos
0005
00 H
0024
0034
0111
0117
0043
0023
.0015
.0015
0989
STABILITY CATEORY 0
IRECTIOK *IND SPEED (K./1EC)
( SECTOR )
N
MHE
HE
EHE
E
ESE
SE
SSE
S
ssv
SV
ysy
y
VHV
Hy
HHM
TOTAL
0-1.3 1
.0071
.4093
.0117
.00(2
.0036
4036
. 4043
.4113
.0144
.4134
4133
4122
. )1 13
. 4 •) 5 4
.4032
.4029
.1373
t-3 0
. 0032
.0133
. 0133
. 0031
. 0031
.0022
.0013
. 003)
.0149
. 0193
0242
0204
.0084
•) ) 1 (
000'
. 0407
139)
3.1-3.1 '
0024
.0137
.0122
.0014
.0007
0013
0009
. 0023
.0083
.0328
0393
417)
. ) ) 21
. ) ) ) )
0 <> 0 )
.4001
. 1 144
I 2-8.2
.001 1
.013*
.0103
.0014
.0007
. 0041
0002
. 0007
.4430
.4291
.0129
4144
00)4
. ) 4 ) •>
.4000
.0001
.1112
8 3-10.8
. 4004
0014
. 0004
. 0007
. 4444
. 4404
4404
. 4404
. 4409
. 4039
4038
>>04 1
4000
) * ) 0
00)0
.0044
0154
>10 .8
. 0440
.0441
.4440
. 0000
.0440
.4444
4440
.0040
0040
. 0403
4005
0010
4000
. ) 4 »
0 1 0 4
.0000
0021
TOTA'.
. 01 34
.0319
. 0479
. 01 30
.0081
. 0094
. 0073
.0194
. 0434
. 0997
1 14 )
06? 1
02il
•1' '' 4 <
0)4)
. 0339
3394
STABILITY CATEGORY E
HMD SPEED (fl/SEC)
3 14-3 0 3 1-3 1 T01AL
0113
.0132
.0181
.0488
.0044
.0443
.0044
0149
0124
.0123
0140
0477
0)64
045!
0031
0438
1320
0043
0194
. 01 98
0044
. 0024
. 0009
0014
0039
0127
0\ 14
0131
0') 1 7
0004
0007
108'
0003
0078
0087
0009
0004
0004
OOOI
0010
0012
0023
4020
4 •) ? <,
4002
0 .) C )
000 )
0000
4282
4426
44i7
0142
.4074
4037
4061
0218
42J3
02i6
AMSU6L
VI KC
PIRECT10N
S 1 S T S 1 B U T 1 0 N
0458
1 3 C 5
1 257
03M
0 1 75
0 1 57
0141
0436
0751
I 308
1 b 04
1 I > 4
0443
0)63
0147
0 1 10
-------
TECHNICAL REPORT DATA .
(Please read Inductions on the reverse before completing)
. REPORT NO.
EPA-910/9-82-090
3. RECIPIENT'S ACCESSI Or* NO.
TITLE AND SUBTITLE
RECOMMENDATIONS ON A SHORTZ/LONGZ S02 AIR QUALITY
MODEL METHODOLOGY FOR THE TACOMA TIDEFLATS AREA
5. REPORT DATE
November 1982
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J. F. Bowers, W. R. Hargraves and A. J. Anderson
8. PERFORMING ORGANIZATION REPORT NO
TR-82-146-01
9. PERFORMING ORGANIZATION NAME AND ADDRESS
H. E. Cramer Company, Inc.
P.O. Box 8049
Salt Lake City, Utah 84108
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
Contract No. 68-02-2547
Task Order No. 4 (Mod. No.' 4
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency, Region 10
1200 Sixth Avenue
Seattle, Washington 98101
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The primary purpose of the study described in this report was to develop a
methodology for applying the SHORTZ/LONGZ complex terrain dispersion models to the
existing and proposed S02 sources located within and adjacent to the Tacoma,
Washington tideflats area. The major tasks of the study were to: (1) review the
meteorological and air quality data available for the Tacoma area to determine
the meteorological conditions associated with the highest observed S02 concentrations
(2) evaluate the performance of the SHORTZ and LONGZ models in the Tacoma area
following procedures currently recommended by the U. S. Environmental Protection
Agency (EPA); and (3) prepare a report specifying procedures for using the SHORTZ/
LONGZ models in the Tacoma area, including source inputs, meteorological inputs and
receptor arrays. Because of time and level-of-effort constraints for the com-
pletion of the study, it was not possible fully to complete all of Tasks (2) and (3).
However, an interim procedure for the use of the SHORTZ/LONGZ models in the Tacoma
area is presented along with recommendations for future work to accomplish these
objectives.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group
Air pollution
Meteorology
Sulfur Dioxide
Turbulent Diffusion
Dispersion Modeling
Tacoma, Washington
Complex Terrain
SHORTZ
LONGZ
'-i. DISTRIBUTION STATEMENT
Release unlimited
19. SECURITY CLASS (This Report/
Unclassified
21. NO. OF PAGES
192
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
------- |