IMPLEMENTATION OF THE PSD
PERMIT PROGRAM IN REGION III
by Ceittsi' (CPK52)
841 CfesslRut Street
J. R. Avery phSad«Jpfeia,PA
P. J. Gunthorpe
W. J. Warren-Hicks
D. K. Wells
TRW
Environmental Division
Research Triangle Park, North Carolina 27709
Contract No. 68-02-3515
Project Officer
Robert J. Blaszczak
Air Media and Energy Branch
U.S. Environmental Protection Agency
Region III
Philadelphia, Pennsylvania 19106
AIR MEDIA AND ENERGY BRANCH
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION III
PHILADELPHIA, PENNSYLVANIA 19106
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DISCLAIMER
This report was furnished to the Environmental Protection Agency by
TRW Environmental Division, Post Office Box 13000, Research Triangle Park,
North Carolina 27709 in fulfillment of Contract No. 68-02-3515, Work
Assignment 10. This document has been reviewed by the Air Media and
Energy Branch, U.S. Environmental Protection Agency, Region III and
approved for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
n
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CONTENTS
Title Page i
Disclaimer ii
Contents iii
Section 1. Introduction 1
Section 2. Tasks Performed 2
PSD Workshop Presentations 2
Dispersion Modeling Course Presentation 4
SHORTZ/LONGZ Computer Program Tape Analysis 5
Baseline Date and Redesignation Plan Review 5
Applicability Guidance 6
Appendices
A. Dispersion Modeling Course Materials A-l
B. SHORTZ/LONGZ Computer Program Tape Analysis B-l
C. Applicability Guidance C-l
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SECTION 1
INTRODUCTION
The Clean Air Act (CAA) as amended in 1977 included requirements for
the Prevention of Significant .Deterioration (PSD) of air quality. The
United States Environmental Protection Agency (U.S. EPA) promulgated
regulations to implement the PSD requirements in the Federal Register
(43 FR 26388) on June 19, 1978. Final amendments to the PSD regulations
were promulgated in the Federal Register (45 FR 52676) on August 7, 1980.
The states were to revise their State Implementation Plans (SIP) to
include this PSD program. Until such time as the SIPs are revised,
the states are delegated the Federal program, or until other interagency
agreements are established, the U.S. EPA is administering the PSD program.
At this time, EPA Region III and the air pollution control agencies in
Region III are and have been engaged in activities which will provide
for the transfer or sharing of PSD program requirements and responsibilities.
The PSD regulations themselves require that new major stationary sources and
major modifications be reviewed with respect to all regulated pollutants
emitted in significant amounts for best available control technology (BACT),
for impact of emissions on ambient air quality, impact of emissions on
established PSD increments, impacts on soils, vegetation and visibility,
an air quality analysis of growth impacts, and an analysis for Class I
areas.
TRW Environmental Division has provided PSD guidance, training and
technical support to EPA Region III and the air pollution control agencies
in Region III. The purpose was to provide for the orderly transfer of the
PSD program, to ensure program integrity, and to provide adequate and timely
support to Region III and these agencies during and immediately following
the transfer of PSD authority.
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SECTION 2
TASKS PERFORMED
Guidance, training and technical support provided to EPA Region III
and the air pollution control agencies in Region III by TRW include:
presentation of two PSD workshops, presentation of a dispersion modeling
course, analysis of SHORTZ/LONGZ computer program tape, review of
Region III baseline dates and the Allegheny County redesignation plan,
and guidance on PSD applicability issues. This section provides a
summary of each task performed by TRW.
PSD Workshop Presentations
To provide guidance and training to the staff of the air pollution
control agencies, PSD workshops were presented by TRW in Charleston,
West Virginia and Pittsburgh, Pennsylvania. These workshops, in
conjunction with the Prevention of Significant Deterioration Workshop
Manual, EPA-450/2-80-081, served two prime purposes:
1. To describe in simple terms the requirements of the
August 7, 1980 PSD regulations found in 40 CFR 52.21; and
2. To provide suggested methods of meeting these requirements,
illustrated by examples.
Each workshop consisted of an audiovisual slide presentation
composed of four sections; Applicability, Best Available Control
Technology (BACT), Air Quality Analysis, and Additional Impacts
Analysis.
The Applicability section provided an understanding of key PSD
concepts. This section also offered specific guidance on how to deter-
mine if PSD review is required for proposed new and modified air
pollution sources and on the review requirements that must be met by
sources subject to PSD review.
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Section Two, Best Available Control Technology, presented an
analytic format which may be used as an aide for identification of
specific BACT requirements. However, the construction and operation
of a new or modified pollution-emitting unit was emphasized as Having
many complex and interrelated impacts on the energy availability,
economy and environment of the affected area. BACT analyses for the
same type of emissions unit and the same pollutants in different
locations or situations may determine that different control
strategies should be applied to the different sites, depending on
the site-specific factors. The BACT analysis was presented as
being an important step in the PSD review process, as it produces
results which provide the majority of the input data for two other
PSD analyses: the air quality analysis and the additional impacts
analysis. Additionally, this section emphasized that BACT analyses
must be conducted on a case-by-case basis.
The Air Quality Analysis section addressed the requirements and
suggested methods for performing air quality impacts analyses. Depending
on the amounts and types of regulated pollutants, subject to an air
quality analysis, this section provided as many as three separate but
interrelated phases of the analysis which may be required. They were:
1. Performance of an increment consumption analysis for
proposed sulfur dioxide (SCL) and particulate matter (PM)
emissions, for comparison to allowable increments;
2. Determination of existing air quality for all pollutants
subject to the air quality analysis; and
3. Analysis of projected future air quality for all applicable
criteria pollutants and any applicable non-criteria pollutants
subject to PSD review. The purpose of this phase is to
determine if there will exist any NAAQS violation or very
high ambient concentration of non-criteria pollutants that
may pose a threat to public health or welfare.
As emphasized in this section, no two analyses are identical and no quick
solution to ensure compliance with all standards and increments exists.
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The final section, Additional Impacts Analysis, provided an under-
standing of the requirements of an additional impacts analysis. The
analysis determines air pollution impacts on soils, vegetation and
visibility caused by emissions from the source or modification under
review, and the emissions resulting from associated growth. This
section offered a basic method for approaching an additional impacts
analysis. However, it was stressed that no "hard and fast" approach to
an additional impacts analysis exists.
The single most important message transmitted in the PSD workshop
and manual strongly suggests that the prospective PSD applicant work
very closely with the PSD reviewing authority, as a good working
relationship may serve to minimize time and resources for preparation
and processing of a PSD application.
Dispersion Modeling Course Presentation
During October 1981, two TRW engineers presented material covering
topics in air pollution meteorology during the first day of a two-day
air quality dispersion modeling course for approximately 15 staff engineers
of the Allegheny County Department of Health in Pittsburgh, Pennsylvania.
The emphasis of the lectures dealt with the following aspects of plume
behavior: (1) Gaussian dispersion, (2) turbulent diffusion, (3) topo-
graphical effects, (4) separated flows, and (5) plume rise. Other topics
covered include general meteorology, meteorological data used in modeling,
pollutant source types, and classes of available air quality models.
Upon completion of the course on air pollution meteorology, the
participants were able to:
1. Describe basic meteorological principles that govern diffusion
of an airborne contaminant;
2. Write the mathematical models that describe atmospheric diffusion;
3. Determine atmospheric stability and the resultant value of
the diffusion coefficient;
4. Calculate plume rise from a stack, given the ambient parameters;
and
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5. Compute ground-level concentrations using the appropriate
dispersion formula under varying emission, ambient and
topographic conditions.
The course required considerable planning and preparation by TRW.
Outlines and text were prepared for handouts to the attendees so their
note-taking requirements were minimal. Also, approximately 25 slides
were prepared for use with an overhead projector. Several example
problems were worked out on the blackboard for class discussion. A
copy of the prepared materials can be found in Appendix A.
SHORTZ/LONGZ Computer Program Tape Analysis
In November 1981, EPA Region III requested that TRW load two
dispersion models onto the Region III disk space on the NCC-UNIVAC
machine. Additionally, testing and verification of the results from
sample data inputs was requested. TRW obtained the SHORTZ/LONGZ computer
program tape and copied new absolute files on EPA Region III disk space.
Test cases for both SHORTZ and LONGZ were run with both the original and
the newly created absolute files. No differences were found in comparisons
between the outputs from either absolute file and the outputs found
in the User's Guide for SHORTZ and LONGZ. An additional test case,
previously performed by Region III with the old version of SHORTZ, was
executed with both the original and newly created SHORTZ absolute files.
Both absolute files produced the same results. These runs and results
from one of the User's Guide test cases were delivered to Region III.
Appendix B contains a copy of TRW correspondence with Region IV concerning
the tape analysis assignment.
Baseline Date and Redesignation Plan Review
During November 1981, several documents concerning EPA Region III
baseline dates and the proposed Section 107 redesignation plan for
Allegheny County, Pennsylvania were reviewed. Baseline date documents,
prepared by Pacific Environmental Services, Inc. (PES) include:
"Determination of PSD Baseline Dates Within U.S. EPA Region III,"
November 1980; "Determination of the Radius of Significant Impact
for PSD Sources Within U.S. EPA Region III," December 1980; and
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"Determination of Revised PSD Baseline Dates for the State of Virginia,"
September 1981. The primary purpose of TRW's review of these documents
was to determine if a revision of the Allegheny County baseline dates
f-
was necessary.
Based upon Federal Register notices, it was determined that Allegheny
County has been designated non-attainment for both sulfur dioxide (SCL)
and particulate matter (PM) since August 7, 1977. Approval of Section 107
redesignations for Allegheny County was published October 21, 1981
(46FR51607) and effective November 20, 1981. This revision redesignated
certain areas within Allegheny County as attainment and unclassified for
S02 and PM. The baseline dates would apparently be set in Allegheny County
as the date of the first complete PSD application in the 107 area or that
would significantly impact the 107 area after November 20, 1981. However,
formal communication with OAQPS on the actual baseline status of redesignated
areas may be necessary.
Applicability Guidance
On February 1, 1982, TRW responded to PSD applicability issues posed
by a staff member of the Allegheny County Bureau of Air Pollution Control.
Guidance was provided concerning the issue of federal enforceability of
physical and operational limitations used in determining PSD applicability.
Additionally, requirements for an applicability determination of a proposed
modification were addressed. For detailed information concerning these
issues, the transmittal letter is provided in Appendix C.
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_ APPENDIX A
• Dispersion Modeling Course Materials
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Dispersion modeling course materials were obtained by TRW
Environmental Division from the documents referenced in this Appendix.
Pertinent information extracted from these documents was used as
lecture materials for presentation to the staff of the Environmental
Protection Agency, Region III and the State air pollution control
agencies.
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TRW
ENVIRONMENTAL ENGINEERING DIVISION
1423.81.JRA.034
October 6, 1981
Mr. Al Cimorelli
U. S. EPA
Curtis Building
6th & Walnut Streets
Philadelphia, PA 19106
Subject: Modeling Course Outline
Dear Al:
Attached please find a draft outline for the modeling workshop in
Allegheny County. I propose that we use an overhead projector and
blackboard for teaching aids. The outline is broken into seven
major topic areas. I believe you should handle area VI and the
complex terrain portion of section VII. Unless you direct us
otherwise, we will be prepared to teach the remaining sections.
Please call me at (919)541-9100 if you have any questions or
comments.
Jfm Avery, Manager
Systems Analysis
JRA:hb
Attachment
cc: Bob Blaszczak (EPA)
Paul Gunthorpe (TRW)
Leigh Hayes (TRW)
Progress Center A _ 3
3200 E. Chtpel Hill Rd./Nelton Hwy.
P.O. Box 13000
Research Tritngle Park. N.C. 27709 (919)541-9100
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Allegheny County, PA Modeling Workshop
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_ Day 1 - Fundamentals of Air Pollution Meteorology
I. Background - Basics of Meteorology
9:00 a.m. A. Horizontal Motion and Fluid Flow
1. pressure gradient force
2. Coriolis force
3. frictional force
4. cyclones
5. anticyclones
9:30 a.m. B. Temperature in the Atmosphere
1. lapse rate
2. stability
3. mixing height
10:00 a.m. C. Atmospheric Circulations and Air Masses
1. primary circulation
2. secondary circulation
a. air masses
b. fronts
3. third order circulations
a. land and sea breezes
b. valley and mountain breezes
c. others (cumulus convection cells, tornadoes, etc.)
II. PIume Behavior
10:30 a.m. A. Plume Dispersion
1. Gaussian model
2. Pasquill stability categories
3. diffusion coefficients
11:30 a.m. B. Turbulent Diffusion
1. mechanical
2. thermal
1:00 p.m. C. Topographical Effects
1. land and sea breezes
2. mountain and valley breezes
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1:30 p.m. D.
2:00 p.m. E.
Separated Flows
1. building wake effect
2. stack tip downwash
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Plume Rise
1. momentum
2. buoyant
3. classifications under various lapse rate
3:00 p.m. III. Meteorological Data for Modeling
A.
B.
C.
fmportant variables
source of data
preprocessed data
3:30 p.m. IV. Source Types
A.
B.
C.
D.
4:15 p.m. V. Cl
A.
B.
C.
D.
point (stacks)
line (conveyor belts, etc.)
area (coal pile, etc.)
volume (building roof monitor)
asses of Models Available
Gaussian
Numerical
Statistical
Physical
Day 2 - Policies and Models
VI. Ai
9:00 a.m. A.
9:30 a.m. B.
10:15 a.m. C.
"10:30 a.m. D.
10:45 a.m. E.
r Quality Modeling Policy
April 1978 Guideline on Air Quality Models (OAQPS)
1. model suitability
2. recommended models
April 1981 Workshop of Regional Meteorologists:
A Summary Report
1. use of non-guideline models
2. measured air quality data in lieu of model estimates
3. models omitted from 78' guidelines
4. models added since 78' guidelines
Non-guideline Models
Good Engineering Practice Stack Height
Fugitive Dust Issue
1. Defined "fugitive dust" in June 78 regs. (exemption)
2. Deletion of "fugitive dust" exemption Aug. 80 regs.
3. Quantifiable fugitive emissions
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11:15 a.m. E. Complex Terrain
1. meteorology
2. modeling
VII. Discussion of Models
11:30 a.m. A. Valley
1. complex terrain screening
2. Gaussian
3. short/long term
4. urban/rural modes
5. multiple sources
1:00 p.m. B. SHORTZ/LONGZ
1:45 p.m. C. COMPLEX I (complex terrain screening)
1. based on Valley algorithm
2. incorporates buoyancy induced dispersion
3. uses hourly met data
2:15 p.m. D. COMPLEX II (complex terrain screening)
1. bivariate Gaussian (uses a )
2. modified buoyancy induced dispersion
3. otherwise identical to COMPLEX I
2:45 p.m. E. CRSTER (single source)
1. Gaussian
2. rural /urban
3. short/long-term
3:00 p.m. F. Industrial Source Complex (ISC)
1. Gaussian
2. wide variety of sources
3. long/short term
4. wake effect, stack downwash, gradual plume rise
3:30 p.m. G. MPTER (multiple sources)
1. Gaussian
2. short-term
3. several model options (buoyancy induced disp., etc.)
.3:45 p.m. H. RAM
1. Gaussian
2. short-term
3. point and area sources
4. urban/rural
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• 4:00 p.m. I. Climatological Dispersion Model (COM)
1. Gaussian
12. long-term
3. urban
4:15 p.m. J. CDMQC
1. expanded version of COM
_ 2. statistical
• 3. shorter averaging periods
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ENVIRONMENTAL ENGINEERING DIVISION
1423.81.JRA.037
October 19, 1981
Mr. Al Cimorelli
EPA Region III
Curtis Building
6th & Walnut Streets
Philadelphia, PA 19106
Subject: Expanded Modeling Course Outline
Dear Al:
Attached is the expanded outline which includes some formulas and
more subject matter. For certain areas we intend to expand the
formulas such as in the case of the Gaussian Plume equation. We
intend to spend the most time on section 2, Plume Behavior.
I will be out of the office this week. If you have any comments
or additions, please refer them to Paul Gunthorpe who will be
preparing and partially presenting this material.
Sincerely,
r ***.-£» /t'>**y^
Jim Avery, Manager
Systems Analysis
PJG:JRA:hb
cc: Paul Gunthorpe
Bob Blaszczak
Progress Center
3200 E. Chapel Hill Rd. /Nelson Hwy. A" 8
P.O. Box 13000
Research Triangle Park, N.C. 27709 (919)541-9100
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Modeling Course Outline (First Day)
I. Background - Basics of Meteorology
A. Horizontal Motion and Fluid Flow
1. Pressure gradient force:
The horizontal component of the pressure force which
cannot be balanced by gravity.
fn - 1 A P
Fn - ' p Ait
Fn Is a force normal to the Isobars which Is a function
of the horizontal pressure gradient and density of air.
2. Coriolis force:
The fictitious force which arises from measurements in a
noninertial system (rotating earth).
Co = 2 fi c sin 4>
Co is the Coriolis force which is a function of the
earth's angular velocity, the earth latitude and the wind
speed.
3. Geostrophic wind equation:
The balance of the pressure gradient force and the Coriolis
force.
i £ = 2C c sin*
ft = angular speed of the earth.
C = geostrophic wind.
4. Curved flow (gradient wind):
The balance of three forces Fn, Co, and Ce (centrifugal
force).
Fn + Co + Ce = 0
Ce = V2/R which is a function of the tangential velocity
V and the radius of curvature R. Rotation about a low
pressure center is referred to as cyclonic (counterclock-
wise in the Northern Hemisphere). Rotation about a high
pressure center is referred to as anticyclonic (clockwise
in the Northern Hemisphere).
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5. Cyclostrophic flow:
The balance between the pressure gradient force and
J centrifugal forces.
6. Frictional flow:
I The friction forces at the earth's surface cause cross
isobaric flow from regions of high pressure to regions of
• low pressure.
™ 7. Thermal wind:
_ The change in geostrophic wind with height caused by
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temperature variation.
VT =
g AT
fT An,
AH _
= thermal wind
| B. Temperature in the Atmosphere
1. Lapse rate:
I The change in temperature of the atmosphere in the vertical
First law of thermodynamics
AH = cvAT + p AV
T/To = (P/Po)R/Cp
6 = potential temperature
• Adiabatic process AH = 0
Poisson's equation
I
Replacing To with 6 in Poisson's equation:
• e _ T /lOOO]0.286
_ V p /
Temperature in an adiabatic environment decreases with
• height.
* 2. Stability
I a. stable
b. neutral
_ c. unstable
| d. conditional (moisture considerations)
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3. Mixing height:
Measure of the vertical distance available for the mixing
of pollutants which takes into account the effect of
inversions.
a. dry adiabatic lapse rate
b. observed vertical temperature profile
C. Atmospheric Circulations and Air Masses
1. Primary circulation
a. zonal flows
b. circulation models
2. Secondary circulations
a. air masses:
Widespread body of air having properties which can
be identified by their horizontal homogeneity,
particularly with respect to temperature and humidity.
b. air mass modification:
by advection, radiation losses, thermodynamic,
turbulence
c. frontal zones
d. cyclonic and anticyclonic disturbances
3. Third order circulations.
a. land and sea breezes
b. valley and mountain breezes
c. fall winds
d. foehn winds
e. cumulus convection
f. tornadoes
II. PLUME BEHAVIOR
A. Plume Dispersion
1. Gaussian model (from Turner's workbook)
a. general equation
X = concentration of a pollutant
A-ll
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x(x, y, 2; H)
Q «*P (-1 ll \ 1 ^P f-i
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• * vfy. v. »i H\ / \ / \ /
(-1 /Z-H\21 + CXP 1-1 /2+H\
v foy / v fc)
Io and o are functions of stability and distance downwind (standard
deviations)
H « effective height
| (Z-H) term accounts for the above ground real source.
(Z+H) term accounts for the imaginary source below.
I b. concentration calculated at ground level
where z « 0
• c. concentration calculated along the center!ine
(-
exp - I H 2
where y * z = 0
• 2. Pasquill stability categories:
• Based on wind speed at 10 meters, incoming solar radiation and
_ cloud cover.
I a. classification
b. urban vs. rural
I 3. Diffusion coefficients:
Related to the deviation in the wind direction given by an azimuth
I angle and elevation angle.
a. rural conditions:
• Pasquill - Gifford (Turner, 1970)
* b. urban conditions:
- McElroy - Pooler (Gifford, 1976)
I c. inversion case:
2.15 DZ « (H..-H); H.. = height of inversion above ground
I d. fumigation case:
H
ouf s o,, (stable) + 5-
tm J' J o
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B. Turbulent Diffusion
1. Mechanical turbulence:
Air motion over the rough surface of the earth.
I Velocity profile U2 = UQ j|-(
| o[
n depends on the roughness of the surface
I 2. Thermal turbulence: momentum transport Is buoyancy.
Richardson number (R.) Is the relation between the production
• of energy by buoyancy forces and the dissipation of energy
by mechanical turbulence.
2)-;
C. Topographical Effects
1. Land and sea breezes
2. Mountain and valley breezes
a. interaction with synoptic flow
b. turbulence
3. Air flow over mountain peaks and ridges.
a. wave classifications
b. rotor flow and hydraulic jump
c. interaction with local circulations
D. Separated Flows
1. Building Wake Effect:
The separation of flow around buildings causing increased
concentrations of pollutants in the downstream separated
region.
a. anatomy of wake
b. minimum plume height
2.5 building heights rule
c. squat vs. tall building
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2. Stack-tip downwash:
Downwash of the plume into the low pressure region in the
wake of the stack occurring with low efflux velocities.
a. minimum efflux velocity recommendation
WQ >1.5 U (Sherlock and Stalker)
b. Nohebel recommends efflux velocities based on heat
emissions
c. plume height equation from Briggs
h1 * h + 2 (VS/U - 1.5) D
E. Plume Rise
1. Important variables
a. rate of heat emission
b. rate of momentum emission
c. wind speed at plume level
d. distance downwind of stack
e. height of source
f. variations in ambient temperature
2. Complete formula near stack (2/^3 law)
Ah = 2
m - - m-
Fm = flux of vertical momentum//^
F * flux of buoyant force/irp
3. Momentum sources
a. Ah = 1.5 _s_, D (Rupp et al.)
b.
where R - V$/U
4. Buoyant sources
AH « *e
AH - (s)b
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where s * stability parameter
v = adiabatic lapse rate
AH a (F)c where F * buoyant
force per unit time per unit mass.
2
JB7 + I
F = g vc
f!
F_
US
1/3
Ah = 1.6
Ah =5.0 F
1/4
in stable air
in stable air
in stable air
X* is distance from the source where the plume
rise is dominated by atmospheric turbulence.
X* = 2.16 F2/5 hs3/5
when X <_ 3X*
1/3
Ah = 1.6 ^
when X > 3X*
Ah = 1.6 F
^2/3
(x)'
1/3 v 2/3
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2 . 16 X . 11 X%
5 + 25 7. + T X.2
+ 4 x / ^
5" 7 t
5 X*i
6. Plume classifications
a. looping
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b. coning
c. fanning ~
d. fumigation
e. lofting
f. trapping
III. METEOROLOGICAL DATA FOR MODELING
A. Important Variables and Data
1. Location (NWS station number)
2. Time (year, month, day, hour)
3. Temperature (dry bulb)
4. Wind (speed and direction)
5. Sky conditions (cloud cover and ceiling height)
6. Mixing height
B. Source of data (federal, state, municipal, or private
organizations which are considered to be representative of the
site in question).
1. National Climatic Center (NCC)
a. hourly surface observations
b. twice daily mixing heights
c. summarized met data (STAR frequencies)
2. Municipal and state agencies (particularly those involved
in pollution, conservation, and port management.
3. Universities
4. Industrial locations
C. Preprocessed Meteorological Data
1. Input data to the preprocessor
2. Output data from the preprocessor
3. Uses of preprocessed met data
IV. SOURCE TYPES
A. Point Sources
1. Plant layout
2. Stack parameters
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3. Boiler size
4. Boiler parameters
5. Operation conditions
6. Pollution control equipment parameters
B. Line Sources
1. Highway automobile exhaust
2. Conveyor belts
3. Rail lines
4. Haul roads
C. Area Sources
1. Emission rates
2. Effective crosswind width
3. Effective height
4. Gravitational settling
D. Volume Sources
1. Surface based sources
2. Elevated sources
V. CLASSES OF MODELS AVAILABLE
A. Gaussian
1. Nonreactive pollutants
2. Examples (CRSTER, ISC, MPTER, etc.)
B. Numerical
1. Multisource applications
2. Reactive pollutants
C. Statistical
1. Incomplete scientific understanding
2. Lack of required data bases
3. Examples (CDMQC, etc.)
D. Physical
1. Fluid modeling facilities (wind tunnel, etc.)
2. Small scale (within a few square kilometers)
3. High level of technical expertise
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Fundamentals of Air Pollution Meteorology
I. Background - Basics of Meteorology
A. Horizontal Motion and Fluid Flow
A condition of hydrostatic equilibrium is said to exist in the
atmosphere when the pressure at any given point exactly balances the
gravitational force at the point. This balance is represented in the
hydrostatic equation
ID * P = ' f 3 A *
where Ap is pressure difference, p is density, g is the acceleration of
gravity, and Az is a height interval. Using the equation of state for
dry air.
(a,) p = j> R T
where R is a gas constant and T is temperature. Rearranging equation
(2) and substituting into equation (1) gives a new form of the
hydrostatic equation.
(3) A p - ~-£T~ A5L
If the pressure force is not exactly vertical, then there must be a
component that cannot be balanced by gravity. The horizontal component
of this pressure force is commonly referred to as the pressure-gradient
force. All of the horizontal motion in the atmosphere is a consequence
of horizontal pressure-gradient forces. The direction of this vector is
from higher to lower pressure as shown in equation (4)
- - JL &P-
" ^T
where F is the pressure-gradient force and An is the change in
horizontal distance normal to lines of constant pressure. Since the
earth is accelerating in several ways, it is a noninertial reference
frame. Noninertial effects cannot be ignored for large scale atmos-
pheric motion. The Coriolis force is an apparent force which arises
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through measurement of a system of particles moving In a noninertial
coordinate system. Thus, the wind blowing in a straight line relative
to the stars will appear to curve when measured on a rotating earth.
This Coriolis force causes a projectile to deflect to the right of the
original direction and is represented by
Co = 3LSL V3 Sin
where Co is the Coriolis force, fl is the angular speed of the earth, V
is the geostrophic wind speed, and 4 is the earth latitude circle. The
term 2 0 sin 4> is commonly referred to as the Coriolis parameter. The
geostrophic wind equation expresses the balance between the pressure-
gradient force and the Coriolis force.
» /
This represents a steady state condition with the wind blowing parallel
to the isobars and perpendicular to the pressure-gradient and Coriolis
forces which now oppose each other. The magnitude of the geostrophic
wind is a function of the Coriolis parameter f, the pressure gradient
Ap/An, and the specific volume a.
f A r\
If the flow is along curved isobars then there is not a simple geostrophic
balance. In gradient flow, the balance involves three forces: pressure
gradient, Coriolis, and centrifugal (Ce). The centrifugal force is a
reaction to the centripetal force of curved flow in which no tangential
acceleration occurs, and
(8) Ce -
is a function of the tangential velocity V and the radius of curvature
R. The rotation about a low pressure center is counterclockwise in the
Northern Hemisphere and is termed cyclonic. In this case, the pressure-
gradient force is balanced by the centrifugal and Coriolis forces. When
flow curves about a high pressure center, the sum of the centrifugal and
pressure-gradient forces act in unison against the Coriolis force. This
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yields a clockwise or antl cyclonic rotation in the Northern Hemisphere.
Another special case of nongeos trophic flow occurs when the centrifugal
force is vastly larger than the Coriolis force. The resulting.cyclostro-
phic wind (V ) represents the balance between the pressure-gradient
force and the centrifugal forces.
The cyclostrophic wind can be an approximation to the real wind in the
atmosphere only near the equator, where the Coriolis acceleration is
small; or in cases of very great wind speed and curvature of the path,
so that the centrifugal acceleration is the dominant one. Frictions!
forces Fr represents the last term in the equation of motion for
horizontal flow.
M
x '
The effect of friction with the ground is transferred through the air by
the irregular motions of particles of fluid. Viscous stress exerts a
force on the boundaries of a parcel proportional to the variation of
velocity with distance across the boundaries (wind shear). The frictional
forces caused by molecular motions are much smaller than those caused by
surface roughness and thermal instability. These effects cause large
irregularities in the flow patterns, or turbulence, which is responsible
for the variation of wind speed and direction for a considerable height.
The friction force opposes the motion of the wind, reducing its speed.
This in turn will reduce the magnitude of the Coriolis force. The
result of this new balance of forces within the friction layer casuses
the wind to turn slightly across the isobars towards low pressure.
Application of the hydrostatic equation shows that where the temperature
is high, the pressure decreases slowly with height, and where it is low
the pressure decreases rapidly. At higher levels, the pressure gradient
is the result of the presure gradient at sea level plus a contribution
due to the horizontal gradient of the average temperature in the layer
up to the particular level. Corresponding to the change in pressure
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This is called the thermal wind Vr
/ \ .. I 3
CO Vr =
I
• gradient with height, there will be a change in the geostrophic wind.
I
The thermal wind is directed along the isotherms with cold air to the
I left in the Northern Hemisphere. It represents the geostrophic balance
between the mean wind-shear vector and the gradient of mean temperature
_ of a layer bounded by two isobaric surfaces.
• 6. Temperature in the Atmosphere
_ The specific heat at constant volume C is defined as
• which is the ratio of the heat input over the temperature change at
constant volume. The same ratio at constant pressure is defined as Cp.
I , x r _ / JULA
(l3) cf ~ I AT)
|v 'r
Now if the ideal gas law (14) is rewritten to express
-- RT
the changes involving P, V, and T,
f/r)
then a new form of the first law of thermodynamics can be written.
AH = c
v
A process in which no heat leaves or enters a given system (AH = 0) is
called adiabatic.
The Poisson's equation relates adiabatic temperature changes experienced
by a parcel of air undergoing vertical displacement to the pressure
field through which it moves.
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Assuming that the process is strictly adiabatic when a reference value
for p is chosen (1000 mb) then the temperature of any parcel brought
down to this height is defined as its potential temperature. Poisson's
equation now takes the form
e =.
where R/C = 0.286. The temperature in an adiabatic atmosphere must
decrease with height. This dry adiabatic lapse rate (r - g/C ) is
approximately 1°C per 100 meters. Ths real lapse rate may be quite
different from dry adiabatic. Above the lifting condensation level
(LCL) an air parcel is lifted along the saturation adiabatic lapse rate,
which is approximately half the magnitude of the dry air case. The
stability of the atmosphere refers to the behavior of a parcel of after
being displaced. For example, if a system is said to be stable, then
after being displaced, it tends to return to its previous state. Stabi-
lities in the atmosphere can be classified according to the magnitude of
the prevailing lapse rate Y when compared to the dry-adiabatic lapse
rate and the saturation adiabatic lapse rate F . A summary of this
classification follows.
Y < FS stable
r < Y < F conditionally stable
Y = F neutral
Y > T unstable
An increase in temperature with height is designated as an inversion.
Inversions are extremely stable because the prevailing lapse rate is
reversed from F or F. Radiative inversions occur at night when the
radiation towards the cold and clear night sky causes cooling at higher
altitudes and are formed by the sinking and compression of air in an
anticyclone.
The mixing height is a measure of the vertical distance available for
the mixing of pollutants and it accounts for the effect of inversions.
The morning mixing height is calculated as the height above the ground
at which the dry adiabatic extension of the morning minimum surface
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temperature plus 5°C Intersects the vertical temperature profile observed
at 1200 GMT. The afternoon nixing height Is caluclated in the same
•tanner except that the afternoon Maximum surface temperature is used for
the adiabatic extension line.
C. Atmospheric Circulations and Air Masses
On the average surface winds are zonal in character (E-W direction
parallel to the latitude circles. The winds aloft become even more
zonal in character as they lose their north-south component and become
essentially true easterlies and true westerlies.
The following is a discussion of various circulation models which attempt
to describe the observed atmospheric circulation. Thermal circulation
on a nonrotating Earth would produce one large hemispherical cell with
northerlies at the surface and souther!ies aloft. The thermal circulation
on a rotating Earth will shift the surface norther!ies toward the southwest
as a result of the balance of pressure-gradient, Coriolis, and frictional
forces. With the absence of frictional effects at the upper boundary,
the northward flow in the upper troposphere will be directed toward the
east, becoming a geostrophic zonal westerly wind.
The tricellular vertical circulation model incorporates the conservation
of absolute angular momentum. Radiative losses from the upper-level
poleward flow of equatorial air results in cooling, and the air sinks by
the time it reaches 30° latitude. When it reaches the surface level, it
spreads out in a horizontally divergent pattern. Some of the air moves
poleward, some of it returns toward the equator. The air which moves
toward the pole already has a westerly component brought about by the
Earth's rotation. As it moves toward higher latitudes, its relative
speed increases. Friction effects transfer momentum from the atmosphere
to the Earth, satisfaction of the conservation of momentum requirement.
The equatorward component of the midlatitude surface divergence loses
its westerly component through friction. The small Coriolis effect
present at such low latitudes deflects the wind into surface easterlies.
The combination of these two effects again satisfies conservation of
angular momentum requirements.
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There are significant faults in this model. The model does not explain
the increase in magnitude with height of the nidlatitude westerlies.
Other influences such as topography are also ignored. -
An air mass is defined as a widespread body of air having properties
which can be identified by their horizontal homogeneity, particularly
with respect to temperature and humidity. Futhermore, vertical tempera-
ture and moisture variations are approximately the same throughout the
horizontal extent of a given air mass. The following is a systematic
nomenclature for the identification of air masses.
m maritime
c continental
A arctic
P polar
T tropical
E equatorial
k colder than the surface over which it moves
w warmer than the surface over which it moves
Air mass modifications may occur by several different processes. Advection
of an air mass over a climatically different region can modify the
original air mass characteristics. Heat losses through radiation out to
space can cause changes in the vertical temperature profile of an air
mass. Thermodynamic modifications to an air mass include adiabatic
heating and cooling, condensation, evaporation, and precipitation.
Turbulent mixing can sometimes occur to considerable heights and will
also contribute modifications to the characteristics of an air mass.
The major features of the secondary circulations are found in associa-
tion with the convergence zones. The primary frontal zones include the
arctic front, the polar front, and the intertropical front. The polar
front is the most active, because it represents the interface between
polar air and tropical air. A front is defined as an interface, or
transition zone between air masses of different density. The concepts
of fronts and frontal surfaces were developed and introduced into meteoro-
logical literature by the Norwegian meteorological school around 1918.
According to the polar-front theory, perturbations in the wind field,
which have components perpendicular to the front, cause deformation in
the frontal surface. These deformations are unstable; they lead to more
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disturbances which develop through successive stages into a traveling
cyclone and finally a closed vortex. The vorticity-advection theory,
which emphasizes the importance of upper air circulations to the traveling
wave disturbances along a frontal surface, represents the state of our
current knowledge concerning the growth and decay of cyclonic and anti-
cycIonic disturbances.
Third-order circulations are more of a local scale which have no effect
on the primary circulation patterns. The land and sea breezes together
represent a diurnal analog of the seasonal monsoon circulation. This
circulation occurs locally along coasts whenever the thermal-contrast
between land and an adjacent body of water are sufficiently great.
Valley and mountain breezes are analogs of the land-sea breeze. Heating
during the day causes a general flow of air up the slopes adjacent to
the valley between them. The situation is reversed at night; air drains
down the slopes and stagnates on the valley floor. Fall winds are
associated with extensive cooling of an elevated plateau or glacier and
are usually much stronger than the related mountain breezes. The foehn
wind or Chinook is a forced wind propagated by the prevailing zonal flow
that arrives at lower levels on the lee side of mountain slopes considerably
wanner than the air it displaces. Cumulus convection occurs when the
local instability generated by surface heating initiates rising columns
of air which reach the condensation level. Each using column is topped
by a cumulus cloud whose base is at the convection condensation level.
Tornadoes are a result of excessive instability and steep lapse rates in
the atmosphere. The central core of a tornado's circulation reaches
unbelievably low pressures. A tornado may in fact exhibit anticyclonic
rotation, although cyclonic rotation is more common.
II. Plume Behavior
A. Plume Dispersion
The assumption is made that the plume spread has a gaussian distribution
2
1n both the horizontal and vertical planes. The standard deviations of
plume concentration distribtuion in the horizontal and the vertical are
o and o respectively. Using x for concentration, we would expect that
-§-
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•
•
where Q Is the source strength and U 1s the wind speed. The mathematical
form of the gaussian function In the y dimension is
(*o)
where A is chosen so that the area under the curve has a unit value.
This will be the case when A « l/i^0/ . jn the gaussian model the
integral over x, y, and z must equal to the total amount of pollutant
emitted. The solution for the plume concentration then takes the form
*
where H is the effective height of the source emission. The (z-H) term
accounts for the above ground real source and the (z + H) term accounts
for the imaginary source below the ground. The concentrations calculated
at ground level are found by setting z = 0 in equation (21).
Concentrations calucalted along the plume centerline simplifies the
above equation by setting y = 0.
For a ground-level source with no effective plume rise, the concentration
is calculated by setting H = 0.
Values for a and o are estimated from the stability of the atmosphere,
which is in turn estimated from the wind speed at a height of about 10
meters and, during the day, the incoming solar radiation or, during the
3
night, the cloud cover. The stability categories range from the most
unstable class A to the most stable class F. The neutral class, D, is
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assumed for all overcast conditions when a low cloud celling exists.
The actual Pasquill stability categoties were designed for use over open
country or rural areas and are less reliable for urban areas. The dif-
ference is due primarily to the Influence of the city's larger surface
roughness and heat island effects upon the stability regime over urban
areas. The greatest difference occurs on calm clear nights. The diffu-
sion coefficients o and o can be related to the deviation in the wind
direction given by an azimuth angle (lateral or cross-wind direction)
and an elevation angle (vertical). Variation in these angles is a
function of wind speed and stability. The Pasquill-Gifford dispersion
coefficients are representative for a sampling time of about 10 minutes.
The values for o and o summarized in the Turner workbook apply strictly
to open level country and for distances from the source of emission
between 0.1 and 100 kilometers. These diffusion coefficients are repre-
sentative for a roughness parameter (z ) of about 0.03 meters. Another
set of dispersion coefficients were based upon the tracer experiements
4
performed in St. Louis and reported by McElroy and Pooler. These
dispersion parameters are representative of urban areas and of surface
roughness of about one meter. The diffusion over cities is enhanced,
compared with that over open country, not only because the surface
roughness is greatly increased but also because of the great heat capacity
of the cities.
In general, the uncertainties in the estimates of a are less than those
of o .
Turner discusses a procedure to handle diffusion when the plume expansion
is limited by an upper-level inversion. The essence of the method is to
calculate the concentrations as if these were distributed uniformly
throughout the layer of height H.. where H^ is the distance from ground
level to the inversion.
One-tenth of the plume centerline concentration extends to the stable
layer when 2.15 o = (H.. - H). If this occurs at a distance x^ from the
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source then equation (25) can be applied at a distance greater than 2xL
from the emission source.
As a surface based inversion breaks up from the upward transfer of
sensible heat from the ground surface, pollutants previously emitted
above the surface into the stable layer will be nixed vertically when
they are reached by the thermal eddies, and ground-level concentrations
can increase. This process is referred to as fumigation. An equation
for the ground-level concentration when the inversion has been eliminated
<•<*
The value for the horizontal dispersion coefficient a r can be approximated
by the following equation
• where p = (h^ - H)/OZ. The fumigation concentration is near its maximum
when h^ = H + 2a and is expressed by the following equation
m
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B. Turbulent Diffusion
Turbulence is represented by eddy motion. An eddy refers to a piece of
air which moves randomly in a fluctuating manner. The effect of eddy
motion is very important in diluting concentrations of pollutants.
Diffusion by turbulence will occur in both the vertical and the horizontal
directions. Mechanical turbulence occurs as air moves over a rough
surface and increases with increasing wind speed. In a laminar or
non-turbulent flow, the rate of diffusion of molecules or particles is
proportional to the coefficient of molecular viscosity, or diffusivity,
u. Because atmospheric flows are turbulent, diffusion in the atmosphere
occurs at a rate which is several orders of magnitude greater than the
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molecular rate. If buoyancy effects are neglected, then the eddy
viscosity 1C controls the mean structure of the wind over the Earth's
surface through the properties of turbulent eddies. More over K is
related to the tangential shearing stress, i.
f
The velocity profile can be approximated by the following equation
where n is a function of the roughness of the surface.
Thermal turbulence occurs during the day as solar heating increases
turbulent mixing and flattens the wind profile as compared with the
night profile. In addition to momentum, turbulent eddies act to transport
heat across the flow. An expression for this eddy heat transport, or
flux, H, can be written by.analogy with equation (29) for the momentum
flux or stress.
(31)
Here the term KH is a coefficient of eddy heat conductivity. The velocity
profile can again be approximated by equation (30) where n is now a
function of the stability of the atmosphere. In unstable air, turbulence
is enhanced by buoyancy forces, while in stable air turbulence is suppressed.
Buoyancy effects can be strongly counteracted by the wind stream, which
in generating turbulence, breaks up the rising eddies. These counteracting
influences, the temperature gradient and the wind speed are related in
the dimensionless gradient Richardson number, Ri. Several forms of
expressing the Richardson number follow _ /j
(35) Hi = •% 77^
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A plume within small turbulent motions will move In a straight line with
a gradual Increase In Its cross-section. A plume within large eddies
will grow little In size, but will meander wildly. A plume within a
variety of eddy sizes (typical of the daytime situation) will grow and
meander as 1t moves downwind.
C. Topographical Effects
Large power plants are often located within the Influence of on-shore
and off-shore breezes. During the day, the stack effluent will tend to
drift over the land Into a relatively stable temperature profile. As
this wind-Induced Inversion burns off from the ground surface, the plume
may be subject to fumigation when the large eddies generated by thermal
turbulence begin to reach the plume height. Daytime solar heating and
nighttime radiatlonal cooling also generate the driving force for moun-
tain and valley winds. These flows are largely dependent on the gradient
conditions existing In the synoptic flows. Gradient conditions can
either assist or Inhibit the development of these local flows. Several
studies have Indicated that a gradient wind speed of approximately 6
meters per second Is necessary for the breakup of the nocturnal drainage
flow. Thermal circulations in a small canyon were studied by Thompson.
The major events of a typical night of radiational cooling in a canyon
follow. First, a thin film of cold air forms on the floor of the canyon
and a short distance up the canyon slopes. A rapid wind shift from
up-canyon to down-canyon wind occurs. A rapidly increasing wind speed
accompanies the continued cooling followed by steady wind the remainder
of the night. A cold core of air persists in the canyon as morning
heating progresses. A rapid wind shift from down-canyon to up-canyon
occurs in the morning. The depth of the up-valley winds is greater than
the drainage flow due to the daytime transport of momentum from higher
levels due to unstable conditions. However, thermal turbulence may mask
the daytime up-slope flow so that it is not as strong as the down-slope
flow. Further studies show that the maximum turbulent kinetic energy
occurs in the late morning and again in the early to mid-afternoon.
Dispersion is generally greater in the afternoon than in the morning,
and the component along the narrow dimension of the valley is greater
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than the cross valley component. Plume spread is greater during the
transitional evening hours than during the early morning stable conditions.
Since cooling and the subsequent development of temperature Inversions
*-
in valleys causes drainage (katabatic winds) of air down the slopes,
inversions can be said to enhance turbulence in this situation. Experi-
ments have shown that for stable and near neutral conditions in the
valley, vertical diffusion coefficients are up to two times greater than
those expected during D stability and in flat terrain. Lee waves are
produced when air flows over mountain peaks and ridges. Motions over a
ridge can be classified based on such characteristics as length and
amplitude. The following summarization will confine itself only to
those cases where the wind blows perpendicular to the ridge. Small-scale
flow is characterized by a wavelength less than or equal to the width of
the ridge and by moderate winds which increase with height through a
considerable depth. Stabilities are not as great as for large waves.
In large-scale flow, the wavelength exceeds the ridge width, stabilities
are greater, and streamlines become packed as air passes over the ridge.
Rotor flow or hydraulic jump flow is usually present with large waves.
Jump flow is characterized by a marked temperature inversion at some
level above ridge height. The waves form a single prominent peak in the
vicinity of the ridge. Large wind speeds result in the subsequent
trough, and then the flow jumps to a higher level downstream with no
further wave activity. The up and down-siope flows must be superimposed
on to the synoptic flow. For example, a leeward-facing slope that
receives direct sunshine could tend to promote and enforce rotary flow
that might be generated in the lee of a mountain. With a shaded flow,
the forces generating a rotary circulation would tend to be inhibited.
Three physical mechanisms can enhance mechanical turbulence in a valley
or canyon. The first effect is the downward transfer of momentum into a
canyon from considerable turbulence generated around rough mountain
tops. Helical-like circulations may result when feeder canyon air
drainage flows act in conjunction with downslope density flows along the
main canyon wall. The third turbulence-enhancing mechanism is wake
turbulence. Wake turbulence is the smallest in scale of the three
turbulence mechanisms.
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D. Separated Flows
Downwash of the plume into the low pressure region in the wake of a
stack can occur if the efflux velocity is too low. Wind tunnel studies
indicate that the downwash effect is slight as long as V > 1.5 u where
o
V$ is the stack exit velocity and u is the horizontal wind speed. If
the plume is very buoyant, the buoyancy forces are sufficient to coun-
teract some of the adverse pressure forces. Other studies have shown
that V. should be at least 20 to 25 ft/sec for small plants and around
9
50 to 60 ft/sec for large plants. Briggs suggests the following equation
for the plume height of a non-buoyant plume near the stack
where h is the stack height and D is the inside stack diameter. Building
wake effect is the separation of flow around buildings which can cause
high concentrations of pollutants in the downstream separated region.
The flow separates to form a large "cavity" behind the building. Back
flow occurs within the cavity so that downwind emissions are carried
upwind if emitted in this region of separated flow. This separation can
also occur on the backside of a hill or in a valley. Let 1. equal the
lesser of the building height h. , or the building width perpendicular to
the wind direction, h . If the plume height h1 is less than (h. +1.5
lb) and the point of emission is on the roof, anywhere within 1./4 of
the building, or within 3 1. directly downwind of the building, the
plume can be considered to be within the region of building influence.
If h1 is less than (hb +0.5 lb), part or all of the effluent is likely
to circulate within the aerodynamic cavity which forms in the lee of the
building. The recirculating cavity region extends to a downwind distance
of 3 h. for a squat building (h > hfa) or 3 h for a tall building (h. >
hw). The enhanced dispersion parameters a ' and o ' are best applied to
w y i
sources placed near buildings (usually within 2 h.) and lower than (hb +
1.5 1. ). For buildings that are taller than they are wide, only the
width parameter, h , is likely to be significant in estimates of a ' and
w y
o '. Likewise for buildings that are much wider than they are tall
(usually greater than 10h.), only the height scale, h., is likely to be
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significant in estimating a'. When the source height is less than 1.2
enhancement of both the vertical and the horizontal dispersion is
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(3C.) V/° 0.1 k,/* + O. 0(,7 (jt - 3
* (37)
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Briggs indicates that for both plumes, buoyancy becomes the dominant
factor, over momentum forces, for a distance downwind on the order of
| 5 seconds times the wind speed. Only buoyant forces need be considered
when dealing with plumes from power plants, smelters, or other large
I Industrial sources. The height of rise for a buoyant plume should be a
function of wind speed
where a is some power. The ambient temperature gradient is also an
important factor such that
•
where S is the stability parameter and is equal to the following.
I 3 ( £L + r
- - + '
• Finally, the plume rise must also be a function of the buoyancy force.
4 H ~ Fc
M F-
I Dimensional reasoning indicates that a - 1/3, b = -1/3, and c = 1/3.
(v?) AH «* (F/us)'/3
I 12
m Some important plume rise formulas are presented below.
stable conditions
I
// z/j -i Stable conditions with
I (s-<) A H = l.d> r X [) Pjume rise a function of
• distance downwind.
'/V - %
/5-^N AH" 5-0 F" 5 stable and calm conditions.
_ A-34
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I
• During neutral and unstable conditions the buoyant plume rise Is affected
_ by atmospheric turbulence at a downwind distance of XA.
* , ,,"/*•. 3/f
(5-3) X,. = 1.IC> F K,
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Within the distance X* equation (53) is valid. Beyond X* the buoyant
plume rise in unstable or neutral conditions is given by the following
equation.
f I
( i
— x.
I u
Stack plumes can be classified according to their behavior during different
I atmospheric conditions. These classifications are based on the fact
that plume spread is directly related to the vertical temperature gradient.
• Looping occurs when the vertical temperature gradient is superadiabatic
and the air is very turbulent. Coning occurs with a vertical temperature
•gradient which is subadiabatic but less than isothermal. Fanning occurs
when the temperature inversion is present both above and below the
plume. Lofting occurs when the plume is above a surface inversion.
| Fumigation occurs when the plume is below on elevated inversion. Trapping
occurs when the plume is sandwiched between an upper level and lower
I level inversion.
III. Meteorological Data for Modeling
A. Important Variables and Data
The location and time of the meteorological measurements is necessary
in order to calculate the solar elevation for stability category determina-
tion. Temperature, wind, sky, and mixing height conditions are also
valuable in stability determinations and calculations of diffusion
coefficients.
B. Source of Data
The National Climatic Center (NCC) in Asheville, North Carolina
archives meteorological data collected primarily by the National Weather
Service (NWS) stations. The data which this center provides includes
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hourly surface observations, twice daily nixing heights from upper-air
stations, and summarized data or STAR frequency tables. Many other
sources of meteorological data exist. Some Municipal and State agencies,
particularly those involved in pollution, conservation, and port management,
take a series of limited or comprehensive weather observations. Educational
Institutions, particularly those colleges and universities with meteorolo-
gical curicula, are also sources of weather data. Industrial locations,
particularly chemical and petroleum sites, many times have large amounts
of unprocessed wind and temperature data. The meteorological data
provided by the NCC must be preprocessed before it can be used as input
to many of the present air quality dispersion models. The preprocessor
calculates hourly values for atmospheric stability and randomizes wind
directions from the surface observations. It interpolates the twice
daily mixing height data to hourly values. The preprocessor also reformats
the meteorological data for model compatibility.
IV. Source Types
A. Point Sources
The following are characteristics which must be taken into
consideration when modeling a point source. A power plant is used for
this example. Plant layout is important to analyze building wake effect
or to determine if stacks should be combined for modeling purposes.
Stack parameters are necessary inputs to the models. Boiler size,
parameters, and operating conditions are used to determine the amount of
emissions from the stack, along with information on pollution control
equipment parameters.
B. Line Source
For line sources, such as highways, data are required on the width
of the roadway and its center strip, types and amounts of pollutant
emissions, the number of lines, the emissions from each line and the
height of emissions. Emission factors from independent studies are
available for sources including haul roads, rail lines, and conveyor
belts. Line sources are usually modeled as volume sources.
C. Area Sources
Emission factors are also instrumental in determining the emission
rates from area sources such as coal piles. Other information which is
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critical In modeling area sources are the effective crosswlnd width, the
effective height, and the gravitational setting.
D. Volume Sources
Volume sources Include surface based line sources such as conveyor
belts and rail lines and also elevated sources such as building roof
monitors. Essentially the same type of Information 1s required to model
volume sources as Is used for area sources. In the case of a long and
narrow line source, It may not be practical to divide the source Into N
volume sources, where N 1s given by the length of the line source divided
by Its width. The line source can be approximated by spacing Individual
volume sources not greater than twice the width of the line source.
V. Classes of Models Available
A. Gaussian
Air quality models can be categorized Into four generic classes:
Gaussian, numerical, statistical, and physical. There are many varia-
tions of the basic Gaussian model, including CRSTER, ISC, RAM, MPTER.
Gaussian models are the most widely used techniques for estimating the
impact of nonreactive pollutants.
B. Numerical
Numerical models are more appropriate than Gaussian models for
multi-source applications that involve reactive pollutants. These
models are not widely applied because they require more extensive input
data bases and resources.
C. Statistical
Statistical or empirical techniques are frequently employed in
situations where incomplete scientific understanding of the physical and
chemical processes or lack of the required data bases make the use of a
Gaussian or numerical model impractical. An expanded version fo the
Climatological Dispersion Model called CDMQC, includes a statistical
model based on the work of Larsen to transform the average concentration
data from a limited number of receptors into expected geometric mean and
maximum concentration values for several different averaging times.
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D. Physical
Physical Modeling involves the use of a wind tunnel or other fluid
modeling facilities. This type of modeling is a complex process which
requires a high level of technical expertise. It can be very useful in
evaluating the air quality impact of a source or group of sources in a
geographic area limited to a few small kilometers.
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REFERENCES
1. Holzworth, G.C. "Mixing Heights, Wind Speeds, and Potential for
Urban Air Pollution Throughout the Contiguous United States,"
AP-101, Environmental Protection Agency, Research Triangle Park,
NC, January 1972.
2. Turner, D.B. "Workbook of Atmospheric Dispersion Estimates,"
PHS Publication No. 999-AP-26. Environmental Protection Agency,
Research Triangle Park, NC, 1970.
3. Pasquill, F. "The Estimation of the Dispersion of Windborne Material,"
Meteorological Magazine. Vol. 90, No. 1063, pp. 33-49.
4. McElroy, J.L. and F. Pooler. "St. Louis Dispersion Study Volume II
- Analysis," AP-53. Department of NEW, Arlington, VA, December 1968.
5. Thompson, A.H., 1967. "Surface Temperature Inversions in a Canyon,"
J. Appl. Meteor.. 6:287-296.
6. Kao, S.K., H.N. Lee, and K.I. Smidy, 1974. "A Preliminary Analysis
of the Effect of Mountain-Valley Terrains on Turbulence and Diffusion,"
A.M.S. Symposium on Atmospheric Diffusion and Air Pollution.
7. Leahey, D.M. and R.D. Rowe, 1973. "Observational Studies of Atmospheric
Diffusion Processes Over Irregular Terrain." Presented at the 67th
Annual Meeting of the Air Pollution Conference Association. Denver,
CO.
8. Sherlock, R.H. and E.A. Stalker. "A Study of Flow Phenomena in the
Wake of Smoke Stacks," Engineering Research Bulletin. No. 29,
Ann Arbor, MI, 1941.
9. Nonhebel, G. "Recommendations on Heights for New Industrial Chimneys,"
J. Inst. Fuel. Vol. 33, pp. 479-511, 1960.
10. Huber, A.H. "Incorporating Building/Terrain Wake Effects on Stack
Effluents," AMS-APCA Joint Conference on Applications on Air
Pollution Meteorology, Salt Lake City, UT, November 1977.
11. Rupp, A.F., et. al. "Dilution of Stack Gases in Cross Winds,
AECD-1811 (CE-1620). Clinton Laboratories, 1948.
12. Briggs, G.A. "Some Recent Analyses of Plume Rise Observations,"
Proc. 2nd Intern. Clean Air Conf., Washington, DC, 1971.
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I Overhead Projections for Meteorology Workshop
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i
Fi(w* 14 TV ramrifcMMfl to
the loial prtmm e«ned b\ • col-
wnn of air of unit cron-fcrlion
WiMrm tn\ two brighti rrprr-
•mri b> d£ n Ju»t A^. prox-idcd
tl" mrnil A^ i> ukcn mull
n
p -
<»
J, 3
orx
A 7
fi
-a z
|-|u p
so
r rT
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Figurr »•« W hm iv*jr» it,
onrnird nonh louth nt rau-t.
ihr prrtiurr.fridirni fonr. ru<|.
•riN mr«urrd in • dirrruon ,
prndirular la thr nolur*
will hj\r rompnnrnti in thr r.
»r»l nonh-inulh dirrrtiom
re «s are
orce
F = - --
In -n -
f An
C o r« o I » 5 /~o r c e
Co r <
f4 Air parucln initiilK
dirrcird «crow thr preuurr field b\
tht presturr.gradient force arc
turnrd cloclcwiK in the Northern
Hemisphere b\ the Conolis "force "
When baJance » achieved between
the pressure and Conolis fortes, (he
mulnng Mind bJows parallel lo the
Hobars This is the gro*irophic
wind
V, 5 in
A-42
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Cerv'l *•••£«*.<)«• I Force
Ce = V*
Figure Ml Gradient wind Do*
around a high pm*ure center The
wind Mowing parallel 10 curved
•oban in a clocliwite direction it a
trtuh of balance between the in-
ward-directed Conohs font and
the ourward-direcird prtwire-gra-
dient and crntnfugal reaction
forces
Gr*-iie.n-| WirvJ
Figure 9-10 Gradient umd flo^
around a lo** pressure renter The
i»ind bl
-------
yr
JWtC'
r~- - .
W-.VXflkH
a.
Vy
3 _ ~
R
0 -f Fo^ ca s
r
i
F- If
\\
Ik
*i*c.
vv^
1000
1004
1006
1012
J- ^ f-
f
Figure f>14 In ihr prrsrnct of
friciional cfTcrii> uhirli op)xn< tin
sprrd of (hr M md balanrr is
*rhir\ rd bf n» Pf n llir prr^nrr-
cradirm forcr and ihr irc/»t >um nl
ihr fnrnon and (
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HBO
South
tifm *-I2 I nor Ming irmpn*lurr fradirnl bottt horn north to nutti and mill hnghi Thiv
cmin an increa«n| prourr |T*di«il from aoulh to north The gradmi n utrprr »i hifhrr lr>r]<
•» mn from • companion along lint AA' with but SB
1005
Thermal wind
10°C-
Flgur* 6.9 Illustration of thermal wind.
Sea-level
geostrophic wind
Wm A
W -
A fir
AH
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IOO
Dftv ADiABATiC
LAPSE MATE
20
21
IOO
22
NEUTRAL
22
20 21
Fig. 7.14 Typical environ-
mental lapse rates. Examples
of vertical temperature pro-
files are shown in comparison
with the dry adiabatic lapse
rate (-1C/100 m). (Smith, M.,
"Recommended Guide for the
Prediction of the Dispenion
of Airborne Effluents," Am.
Soc. of Mech. Engrs.)
I0°
[x
„ x
ISOTMEHMAL
v.
19 20 21
100
/
- XX A
Ny
19 20
TEMPERATURE I*C)
Figure 7-12 \ pjru-l will return
lo it* original loci warrm-r than
when II left it if precipitation re-
moves some condensation This
process n pscudo-adiabatir. the
parcel'* potential temperature
increases
l&&»t*u^
Twnptratur*
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Figure 7-14 (fll An unsaturated parrel is stable when ihr prevailing lapse rair is loss than (In
adiabatir lapsr rate, ft, A saturated parrel is stable when thr prr\ailinc lapse rate is lev. than ili<
moisi-adiabatic lapse rate.
4^jM«4C JJ.,.i,i^m.V' ,,t «fci • .*
Figure 7-15 When the prevailing lapse rate is between the adiabalic and numi-Adi.ib.nii lapse-
rates, 10) an unsuiuraled parrel is Mitble, and
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7.1
f
3
n
3-
C
a
i
n
«•+
n
§
03
3
C
SJ.
3
o
3
CO
(O
n
(A
CO
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7.
(O
re
O)
s
VI
?
c
a
3
a
u>
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Figure 10-2 ThermalK dirrci
circulation on a nonrotating ranh
Surface easterlies
Westerlies aloft
Equator
Figure 7.2 Hadley model of general circulation • single arrows - winds
near ground; double arrows—winds aloft.
Figure 10-5 Trirrllular vertical
circulation model
Figure 10-€ Circulation modrl
(After Palme'n ) This modrl over-
comes the weaknesses in the model
thown in Figure 10-5. Note both
the polar and subtropical jet
streams are accounted for
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Stratosphere
Tropical air
PolaT^'ffilEty'a*
H
A B C D
Figure 11.5 Stages in the lite cycle of a wave cyclone: middle section repesents surface weather maps
at various times; upper and lower sections, vertical cross sections at positions of dashed
lines in middle section. A. Growing wave. B. Mature wave. C. Partially occluded wave. D. Wave
near completion of occlusion process. [After C. L Godske, T. Bergeron, J. Bjerknes, and
Ft. C. Bundgaard, Dynamic Meteorology and Weather Forecasting (Boston: American Mete-
orological Society, 1957).]
ca 70km c«200km
c«300km
caSOOkm
Idealized wave cyclone model: upper-vertical cross section north of wave cyclone; middle -
representation of frontal wave and streamlines on surface weather map; lower—vertical
cross section through warm sector. Shading shows area of current precipitation. [From
J. Bjerknes and H. Solberg, Geofysiske Publikasjoner (1922).]
600
¥
800
1000
B
Schematic vertical cross aection showing temperature dis-
tribution across a frontal zone.
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Fig. 7.8(o) Sea breeze during
the day.
SOLAR
INPUT
1 t
WARM AIR
RISES
WIND >
SR 1,000 METERS
< WIND
/'/7/ A**/// /*^-
A
OCEAN OR LAKE
Figure 5.7 Schematic illustration otjlow in a valley: (A) in the early afternoon when the valley and
up-slope winds are occurring: (B) about midnight when the flow is down the valley and the
slope. [After F. Defant in Compendium of Meteorology, ed. T. f. Malone (Boston: American
Meteorological Society, 1951). p. 665.]
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(x.-y.Z)
Figure 3-1. Coordinate system showing Gaussian distributions in the horizontal and vertical.
an
Plnn\e Cor\ce.n~k ration
u
exPN~P&
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Appendix 2: CHARACTERISTICS OF THE
GAUSSIAN DISTRIBUTION
The Gaussian or normal distribution can be de-
picted by the bellshaped curve shown in Figure A-l.
The equation for the ordinal* value of this curve is:
This area is found from Eq. (A.2):
/P
_, "^
exp (—0.5 p*) dp
(A.2)
Figure A-2 gives the ordinate value at any distance
from the center of the distribution (which occurs
at z). This information is also given in Table A-l.
Figure A-3 gives the area under the Gaussian curve
from — x to a particular value of p where p —
Figure A-4 gives the area under the Gaussian
curve from —p to +p. This can be found from Eq.
(A.3):
x —
Area (—p
exp (—0.5 p2) dp
/+P
-75=
\/2T
-P
(A.3)
i.o
Of
oa
0.7
o t
o $
04
0 3
02
O.I
0.0
Figure A-l. The Gaussian distribution curve.
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13
SOURCE
GROUND;!,-- —
IMAGE V.
SOURCE
Fig. 8.3 Source and image source below ground, used to calculate the
concentration owing to a plume. In the shaded region, the pollution ic
increased by the amount corresponding to the image source.
-t —
77
^-" (Z-H)J
/
\
(Z+H)
\///////s//s///?sr Z'O
—
Fig. 8.4 Coordinate system for real source and imaginary source.
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Table 3-1 KEY TO STABILITY CATEGORIES
Day Night
Surface Wind
Speed (at 10 m) 'nC("ning Solar Radiation Thinly Overcast
m sec-i ' or =-3 8
Strong Moderate Slight -4,'8 Low Cloud Cloud
<
>
2
2-3
3-5
5-6
6
A
A-B
B
C
C
A-B
B
B-C
C-D
D
B
C
C
D
D
E
D
D
D
F
E
D
D
The neutral class, D, should be assumed for overcast condition: during
day or night.
A-56
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Ql
I K>
DISTANCE DOWNWIND, km
Fig. 8.5 Horizontal dispersion coefficient u a function of down-
wind distance from the source. (Turner, 1970.)
WXX) :
KX)
E
k-
100
DISTANCE DOWNWIND, km
Fig. 8.6 Vertical dispersion coefficient as a function of downwind
distance from the source. (Turner, 1970.)
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Table 7 Vertical Diffusion oz over St. Louis
Compared with Diffusion over Open Country63'64
Downwind
distance.
km
1
10
Location
City*
Cityf
Open country
City*
Cityf
Open country
Ratio of oj to value in
neutral conditions for
stability categories
BCD E-F
4.5 2.7 1.7 0.7
4.0 2.4 1.5 0.6
3.2 1.9 1.0 0.5
9 3.4 1.0 0.3
11 4.1 1.2 0.4
6 2.4 1.0 0.3
•Using McElroy and Pooler's curve for B* tO.Ol in their
Fig. 2.
fUsing data for bulk Richardson number B * tO.Ol in
evening conditions only.
10'
10-
10'
-E-F
I Mill
Table 8 Formulas Recommended by Briggs' 9 for
oy(x)and oz(r); IOJ <* < 10" m,
Open-Country Conditions
Pasquill
type oy, m oz, m
A-B 0.32*0+0.0004* )~* 0.24*(1 + O.OOU)*>
C 0.22x(l+ 0.0004*)- * 0.20*
D 0.16JC(1 + 0.0004*)'* 0.14jt(l + O.OOOSi)-*4
E-F O.llocU + 0.0004xri» 0.08^(1 + 0.0015.x)' *
10"
10-
10T
UT| I \i ITlc
A-B
Mill
102
103
10*
10=
«. DOWNWIND DISTANCE (m)
10' 10" 10"
x. DOWNWIND DISTANCE (ml
1CT
Fig. 7 Curves of oy and o2 based on interpolation formulas by Briggs1' for flow over urban areas (see
Table 10); from Hosker."
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n
GroixnJ " lev/e-1 CoftCfcn Tr«L,4i"on belou>
HI.
; u K,
exp
- fhi-
i * H + J ffi -- K f A H
2.15 gT (stable) -*• H tan J5°
2.15
— a, (stable) + H/8
(5.4)
A Gaussian distribution in the her .ontal is as-
sumed.
BOUNDARY OF
STABLE PIUME
t$*
2.JS o-y* H lan 15* '
i.n
(FUMIGATION)
Figure 5-1. Diagram showing assumed height, h. and °>
during fumigation, for use in equation (5.2).
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too
soo
.400
te
•
•
c
£300
«9
IW
X
200
100
0
Figure
URBAN AREA
GRADIENT WIND
SUBURBS
LEVEL COUNTRY
1-2. Examples of variation of wind with height over different size roughness elements (ngures are percentages
of gradient wind); (from Davenport, 1963).
600
600 -
400
HEIGHT
ABOVE
GROUND(m)
300-
200 -
100-
0*1—^
01 234 56709 10 II
WIND SPEED (m/*te)
Fig. 7.5 Change of wind speed profile with stabili-
ty. The frictional drag reduces the wind speed
close to the ground below that found at the
gradient level. (Smith, M., "Recommended Guide
for the Prediction of the Dispersion of Airborne
Effluent*,"Am. Soc. ofMech. Engrt.)
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(*)
Fig. 7.6(0) Plume dispersing
in a field of small eddies. A
plume in a hypothetical field
of email turbulent motions
will move in a relatively
straight line, with a gradual
increase in its cross section,
(6) Plume dispersing in a field
of large eddies. If the eddies
are all very large compared to
the plume dimensions, the
plume will grow very little in
size, but will meander wildly.
(c) Plume dispersing in a field
of varied eddies. The typical
daytime atmosphere has
eddies of an infinite variety of
sizes, and a dispersing plume
both grows and meanders as it
moves downwind.
(c)
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Schematic diagram showing streamlines based on observed lee waves. The
upstream velocity profile is indicated on the left. (After Cerbier and Berenger,
1961.)
10
20
40
4 .
o
<
!H
i •
so
I
70
80
StrtuntlMf
$*»tr» Torbalcncc
I I I I
10 2O 10 40
Dtaairr (km) from Kidgc
SO
60
70
•O
ri(rer» 7d. Tht Untrr Dlm*«k>M of tfw LT7 ind »« Cr»wr til«»t of tfi* Am
Of Sevm Tvtalriirt DliUBfr-l* *» Slmmttor and T«fcal«wc
of Hf*««bc /ump Typo bom WIT* Trr*'-
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GRADIENT FLOW
Figure 8. Schematic Illustration of Mountain Top Influences Upon the Gradient Level Flow Component and the
Downward Transporting of Gradient Flow Momentum.
(from Start et al. 1973)
, „ ., FEEDER
|(r~ " CANYON
Figure 9. Schematic Illustration of Circulations Triggered by Stojn- Density Flows ami
Air Drainage from a Side Feeder Canyon.
(from Start ct al. 1973)
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Figure lOa. Schematic View of the Type of Terrain Capable of Affecting the Woke Turbulence.
This same terrain is depicted in Figure lOb with arrows added to chow the type of secondary air
flow caused by such protrusions into the primary flow of the canyon.
(from Start et ai. 1973)
A-64
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TWO DIMENSIONAL CANYON FLOW
Figure lOb. Schematic Illustration of Turbulent Wake Effects Caused by Obstacles Protruding Into
the Primary Flow Pattern.
A-65
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(0) STACK DOWN WASH
(*> BUILDING DOWNWASH
(r) TERRAIN
Fig. 2.1 Undesirable terodynamic effects.
A-66
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Fig. 7.9(o) The pattern of
flow round a cylinder when
there is no viscosity. (6) The
effect of viscous forces is to
bring the flow to a standstill
at S, where separation takes
place.
Fig. 7.10(o) Downwash in
the separated region of a
stack.
K' = K
A-67
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3.0
VELOCITY
OFILE
BACKGROUND
FljgW
DISPLACEMENT
FLOW
OROUND
BUILDING
CAVI1
Fig. 7.11 Mean flow around a cubical building. The presence of a
bluff structure in otherwise open terrain will produce changes in
the wind flow generally similar to those shown. (Smith, M.,
"Recommended Guide for the Prediction of the Ditpenion of
Airborne Effluentt," Am. Soc. ofMech. Engn.)
Fig. 2.2 Flow past t typical power plant
<"""-"
~*~^«l»w--(J
/
to)
Fig. 7.12(o), (6) Separation effects on plume dispersion.
(Smith, M., "Recommended Guide for the Prediction of the
Ditpenion of Airborne Effluents," Am. Soc. ofMech. Engrs.)
A-68
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Disersion Parameters ^ J -/
in order -fc
i
/llme
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A H =
AH =
D
AH =
A H =
AH* I.
u
AH - A. 1
u s
u
_2* _L i y_ /* i I'
•~2. ^* • • " •* • •
•V " 1 if \S * ^
4 -^-^
T «- ^r
F
X
r
Rg. 9.1 Effective stack height. In the formulas
u»ed it is assumed that dispersion begins at a
point directly above the stack, whose height (H)
the
A-70
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HEIGHT
HEIGHT
HEIGHT
, 1
\
Ss:
TEMP LOOPING
HEIGHT
V
r-""-
TEMP CONING
TEMP FANNING
V -r"""
TEMP LOFTING
HEIGHT
HEIGHT
's
TEMP FUMIGATION
TEMP TRAPPING
A-71
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SCHE
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FIGURE
TEOROLOG
DATA PREPROCESSOR
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A-72
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A-73
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APPENDIX B
SHORTZ/LONGZ Computer Program Tape Analysis
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I TRW
ENVIRONMENTAL ENGINEERING DIVISION
1423.81.JRA.046
December 24, 1981
Mr. Al Cimorelli
U.S. EPA - Region III
Curtis Building
6th and Walnut Streets
Philadelphia, PA 19106
Subject: SHORTZ/LONGZ Computer Programs
Dear Al:
During November, we obtained the SHORTZ/LONGZ computer program tape and
associated Users Guides from you. Our objective was to load the two models
to the NCC-UNIVAC machine and to test and verify the results from several
sample data inputs. We have completed the assignment and are delivering
the results from one of the test cases with this letter. The new absolute
files have been copied to your disk space on the NCC-UNIVAC machine and
are titled: QUARK*ABSLSM.LONGZ and QUARK*ABSLSM.SHORTZ. The work we
performed is described below.
Because of the use of an uncommon tape format on the delivered tape, we had
to make several attempts at loading it to disk. After the successful copy
to disk, we found the tape contained source code, relocatable elements and
absolute files for both programs. The attached table lists the files found
for each program. During conversations with User Services personnel, we
were informed that the relocatable and absolute files would not run correctly
on the system because of a recent operating system modification. We reasoned
that the test cases should be run with both the delivered absolute code and
with a new absolute code created by compiling and link-editing the delivered
source code.
The two test cases on the tape and in the Users Guide for both SHORTZ and
LONGZ were run with both the delivered absolute file and newly created
absolute file. No differences were found in comparisons between outputs
for either test case run under the delivered and newly created absolute
file. Also, no differences were found in comparisons between the outputs
from either absolute file and the outputs found in the User's Guide for
SHORTZ and LONGZ. We concluded that there was no difference between the
delivered models and the models used to execute the test cases in the
User's Guide.
Progntt Cfftttr B-2
&200 £. Cfttpef Hill Rd./Nelton Hwy.
B»0. Box 13000
Ruetrch Triwglt P»rk, N.C. 27709 (919t S41-91OO
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1423.81.JRA.046
December 24. 1981
Page 2
Based upon telephone conversations with you in early December, we agreed
to execute one more test case, a sample case you had performed with the
old version of SHORTZ. SHORTZ runs with both the original and newly
created absolute files were prepared using the file from your disk space
entitled QUARK*DATFL.PPLSUN. Both absolute files produced the same
results. These runs are enclosed for your review.
At this time, we are performing no further work with the models. The runs
we performed show consistency with the original model. However, the new
model has not been tested by us to evaluate the impacts of the modifications
implemented by H.E. Cramer and Company.
I will contact you during the first week of January to discuss these results
and other requirements you may have concerning these or other models. TRW
will be closed for the week between Christmas and New Years. I hope you
enjoy the holidays.
'Jim Avery, Manager
Systems Analysis
JRA:WWH:clg
Enclosures
cc: Mr. Bob Blaszczak
B-3
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FILE NAMES AND TYPES FOR
SHORTZ AND LONGZ DISPERSION MODELS
I.
LONGZ
Type
FOR
FOR
FOR
ASM
ELT
ELT
FOR
FOR
REL
FOR
ABS
REL
REL
REL
REL
REL
REL
ELT
ABS
/•> File Name
^
A6A*LOMGZ(1)
v LONGZ/LONGZ(0
TITLR/LONGZ(0
ASSIGN/LONGZ(0)
CONTRL/LONGZ(0)
EXMPL1/LONGZ(0
EXMPL2/LONGZ(0
INPOUP/LONGZ(1)
OUTPT/LONGZ(1)
CONTRL/LONGZ
MODEL/LONGZ(5)
LONGZ
LONGZ/LONGZ
TITLR/LONGZ
- ASSIGN/LONGZ
INPOUP/LONGZ
OUTPT/LONGZ
MODEL/LONGZ
COLECT/LONGZ(3)
LONGZNEW
Comment
Original absolute file
Newly created absolute file
II.
SHORTZ
Type
FOR
FOR
FOR
FOR
FOR
FOR
FOR
ASM
ELT
FOR
REL
FOR
ABS
FOR
REL
REL
REL
REL
REL
REL
File Name
AQA*SHORTZ(1)
SHORTZ/SHORTZ(0)
OUTPT/SHORTZ(0)
TITLR/SHORTZ(0)
ASSIGN/SHORTZ(0)
ACM/SHORTZ(0)
ACCM/SHORTZ(0)
ZRO/SHORTZ(0)
CONTRL/SHORTZ(0)
EXMPL2/SHORTZ(0)
INPOUP/SHORTZ(1)
CONTRL/SHORTZ
MODEL/SHORTZ(6)
SHORTZ
ERFX/SHORTZ(1)
SHORTZ/SHORTZ
MODEL/SHORTZ
OUTPT/SHORTZ
INPOUP/SHORTZ
ASSIGN/SHORTZ
ACM/SHORTZ
Comment
Original absolute file
B-4
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II. SHORTZ (continued)
Type
REL
REL
REL
REL
ABS
ELT
ELT
File Number
ACCM/SHORTZ
ZRO/SHORTZ
ERFX/SHORTZ
TITLR/SHORTZ
SHORTZNEW
EXMPLl/SHORTZd)
COLECT/SHORTZ(9)
Comment
Newly created absolute file
B-5
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APPENDIX C
Applicability Guidance
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ENVIRONMENTAL ENGINEERING DIVISION
T310.82.JRA.002
February 1, 1982
Mr. Don Graham
Allegheny County Health Dept.
Bureau of A1r Pollution Control
301 39th Street
Pittsburgh, Pennsylvania 15201
Dear Mr. Graham:
In response to our January 20, 1982 conversation, I have clarified the issue
concerning federal enforceability of physical or operational limitations used
in determining PSD applicability.
The August 7, 1980 PSD regulations (45 FR 52736) require that physical or
operational limitations used for determining whether a source or modification
would emit (or emits) a particular pollutant in "major" or "significant" amounts
be federally enforceable. EPA temporarily stayed this requirement on July 15,
1981 (46 FR 36699). Instead, the fundamental physical and operational design of
a proposed project was to be considered when estimating emissions. This tem-
porary stay was not extended by EPA as published December 17, 1981 (46 FR 61613).
Based on expiration of the stay, physical or operational limitations must be
federally enforceable as required by the August 7, 1980 PSD regulations.
During our telephone conversation, you described a situation which formed the
basis for our discussion. My understanding of the situation is described below.
An existing major stationary source (>250 tons per year) located in Allegheny
County has questioned whether PSD would apply to their proposed modification.
Emissions units at this source include eight existing boilers and one existing
standby boiler. The source has considered operating the standby unit in addition
to the eight boilers presently operated, which would result in an increase of
18 Ib/hr of sulfur dioxide emissions.
Based on the requirement of federally enforceable physical or operational
limitations and the information you have provided us, the above modification
would be required to undergo PSD review for sulfur dioxide and any other pollutants
for which emission increases would be significant. However, PSD review would
not be required if the source chose to obtain federally enforceable limitations,
such as limitations on fuel sulfur content or operation hours, etc., such that
the emissions increases of the proposed project would not equal or exceed the
PSD significance level for any pollutant regulated by the Act.
Should PSD review be required, submission of the following Information would be
required by the applicant for each subject pollutant.
• A demonstration that Best Available Control Technology (BACT) is
being applied to each new or modified emissions unit with
potential emissions of one of the subject pollutants.
Progress Center
3200 E. Chapel Hill Rd./Nelson Hwy. C- 2
P.O. Box 13000
Research Triangle Park. N.C. 27709 (919) 541-9100
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T310.82.JRA.002
February 1, 1982
Page 2
• An analysis of existing air quality, Including submittal of
ambient monitoring data.
• An analysis of the source's impact on total air quality for
criteria pollutants to ensure compliance with the National
Ambient Air Quality Standards (NAAQS).
• An analysis of the source's impact on air quality for non-
criteria pollutants.
t An analysis of PSD Increment consumption for PM and S02-
• An analysis of source related growth impacts.
• An analysis of source related impacts on soils, vegetation,
and visibility.
• A Class I area analysis.
If I may be of any further assistance, please do not hesitate to contact
me at (919)7541-9100.
Sincerely,
_ iger
Systems Analysis
I JRA:DKW:med
cc: Mr. Bob Blaszczak
C-3
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1.
4.
7.
9.
REPORT NO. • 2.
903/9-82-006
TITLE AND SUBTITLE
IMPLEMENTATION OF THE PSD PERMIT
PROGRAM IN REGION III
AUTHOR(S) , . _ , „ ,
J. R. Avery, P. J. Gunthorpe,
W. J. Warren-Hicks, D. K. Wells
PERFORMING ORGANIZATION NAME AND ADDRESS
TRW Engineering Division
P. 0. Box 13000
RTP, NC 27709
12. SPONSORING AGENCY NAME AND ADDRESS
U. S. Environmental Protection Agency
Air and Media Energy Branch
Region III
Philadelphia, PA 19106
3. RECIPIENT'S ACCESSION NO.
S. REPORT DATE
6. PERFORMING ORGANIZATION CODE
B. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-3515
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16
17
a.
. ABSTRACT
KEY WORDS AND DOCUMENT
DESCRIPTORS b.lDENTI
18
DISTRIBUTION STATEMENT 19. SECU
UNCL
RELEASE TO PUBLIC 20 SECU
UNCL
ANALYSIS
FIERS/OPEN ENDED TERMS C. COSATI 1 icId/Group
RITY CLASS (TlusKeport) 21. NO. OF PAGES
ASSIFIED
fl'TY CLASS (Tluspage) 22 PRICE
ASSIFIED
EPA Form 2220-1 (R*v. 4-77) PREVIOUS COITION is OBSOLETE
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