United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-450/4-80-031
November 1980
Air
&EPA
Workbook for Estimating
Visibility Impairment
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EPA-450/4-80-031
Workbook for Estimating
Visibility Impairment
by
Douglas A. Latimer and Robert G. Ireson
Systems Applications, Inc.
950 Northgate Drive
San Rafael, California 94903
Contract No. 68-02*0337
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise, and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
November 1980
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This report is issued by the Environmental Protection Agency to report technical data of
interest to a limited number of readers. Copies are available - in limited quantities - from
the Library Services Office (MD-35), U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina 27711; or, for a fee, from the National Technical Infor-
mation Service, 5285 Port Royal Road, Springfield, Virginia 22161.
Publication No. EPA-450/4-80-031
11
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Preface
This workbook provides screening techniques for assessing visibility
Impairment from a single emissions source. EPA believes these techniques
are at a point where the results should now be employed to assist decision-
makers in their assessments. The approach is through a hierarchy of
three levels of analysis, somewhat analogous to that in EPA's "Guideline
for Atr Quality Maintenance Planning and Analysis Volume 10 (Revised):
Procedures for Evaluating the Air Quality Impact of New Stationary
Sources," EPA-450/4-79-001. Frequent consultation between users and
decision-makers is encouraged so that difficulties, misapplications or
unjustified interpretations can be avoided.
One option in the level-2 analysis and the level-3 analysis are
based on the Plume Visibility Model (PLUVUE) and examples/applications
are provided based on output from this model. EPA has also published
the "User's Manual for the Plume Visibility Model (PLUVUE),"EPA-450/4-
80-032. However, the Agency has not yet recommended any visibility
model for routine use in regulatory applications.
iii
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ACKNOWLEDGMENTS
The guidance, helpful comments, and the idea for the screening
analyses approach contributed by the EPA Project Officers, Steven Eigsti
and James Dicke, are much appreciated. William Malm of the EPA's Environ-
mental Monitoring and Support Laboratory at Las Vegas deserves thanks
for his suggestions regarding the use of contrast and contrast reduction
as the basis for this workbook.
The efforts of the authors of the workbook, Douglas A. Latimer and .
Robert G. Ireson, under Contract No. 68-02-3337 with Systems Applications,
Inc., San Rafael, California, are gratefully acknowledged. Also at SAI,
Robert Bergstrom and Thomas Ackerman provided the computations based on
Mie scattering theory, which are the basis of many of the tables and
figures in this report, while Hoi-Ying Holman and Clark Johnson exercised
the visibility computer model for the reference tables and figures
provided in the appendix.
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CONTENTS
Figures vi
Tabl es x
Nomenclature xitt
1 INTRODUCTION 1
1.1 Classes of Visibility Impairment 2
1.2 Approach Used in This Workbook 4
2 GENERAL CONCEPTS 7
2.1 Physical Concepts Related to Visibility Impairment 7
2.1.1 Visual Perception 7
2.1.2 Fundamental Causes of Visibility Impairment 8
2.1.3 Atmospheric Optics 11
2.1.4 Plume Visual Impacts 16
2.1.5 Characterizing Visibility Impairment 19
2.2 Plume-Observer Geometry 27
2.3 Characterizing the Frequency Distribution of Plume
Visibility Impacts 35
2.3.1 Wind Speed 39
2.3.2 Wind Direction 39
2.3.3 Atmospheric Stability 43
2.3.4 Background Ozone .Concentration 44
2.3.5 Background Visual Range 44
2.3.6 Study Area Topography 45
2.3.7 Season and Time of Day 45
2.3.8 Model Runs 45
3 LEVEL-1 VISIBILITY SCREENING ANALYSIS 47
3.1 Derivation of LeveT-1 Screening Analysis 47
3.1.1 Impacts of Particulate and NOX Emissions 50
3.1.2 Impacts of SOg Emissions 53
3.2 Instructions for Level-1 Screening Analysis 56
3.3 • Example Applications of the Level-1 Analysis 61
3.3.1 Example 1 61
3.3.2 Example 2 63
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4 LEVEL-2 VISIBILITY SCREENING ANALYSIS 65
4.1 Identification of Worst-Case Conditions 65
4.1.1 Location of Emissions Source and Class I Area(s) 66
4.1.2 Meteorological Conditions 68
4.1.3 Background Ozone Concentration 89
4.1.4 Background Visual Range 91
4.2 Hand Calculation of Worst-Case Visual Impacts 92
4.2.1 Determining the Geometry of Plume, Observer, Viewing
Background, and Sun 93
4.2.2 Calculating Plume Optical Depth 99
4.2.3 Calculating Phase Functions Ill
4.2.4 Calculating Plume Contrast and Contrast Reduction 117
4.3 Use of Reference Tables for N0£ Impacts. 119
4.4 Use of Reference Figures for Power Plants 121
4.5 Use of the Computer Model * 121
4.6 Example Calculations 121
4.7 Summary of Level-1 and Level-2 Procedures 122
5 SUGGESTIONS FOR DETAILED VISIBILITY IMPACT ANALYSES
(LEVEL-3) 131
5.1 Frequency of Occurrence of Impact 132
5.2 Appearance of Impacts 133
5.3 Impacts on Scenic Beauty ; 141
5.4 Impacts of Existing Emissions Sources 143
5.5 Regional Impacts 144
APPENDIXES
A CHARACTERIZING GENERAL HAZE 147
A.I Wavelength Dependence 147
A.2 The Contrast Formula 148
A.3 Quantifying Increases in Atmospheric Haze 149
A.3.1 Plume Impacts 150
A.3.2 Regional Haze Impacts 153
A.4 The Effect of Increased Haze on the Contrast of
Landscape Features 153
A.5 Summary 156
B PHASE FUNCTIONS 161
C PLUME DISCOLORATION PARAMETERS FOR VARIOUS N02 LINE-
OF-SIGHT INTEGRALS AND BACKGROUND CONDITIONS 189
D REFERENCE FIGURES AND TABLES FOR POWER PLANT
VISUAL IMPACTS 241
vi
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E TWO EXAMPLE APPLICATIONS OF THE LEVEL-1 AND
LEVEL-2 ANALYSES 323
E.I Example 1—Coal -Fired Power Plant 323
E.I .1 Level-1 Analysis 323
E.1.2 Level-2 Analysis 326
E.I.3 Calculation of Plume Optical Depth 342
E.I.4 Phase Function Calculations 348
E.I.5 Calculating Plume Contrasts 352
E.I.6 Calculating Reduction in Sky/Terrain Contrast
Caused by Plume 355
E.I.7 General Haze Effects 356
E.I.8 Comparison of Results with Reference Tables 357
E.2 Example 2—Cement Plant and Related Operations 359
E.2.1 Level-1 Analysis 359
E.2.2 Level-2 Analysis 362
REFERENCES 371
vi i
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FIGURES
1 Schematic of Visibility Screening Analysis Procedure.
2 Effect of an Atmosphere on the Perceived Light Intensity
of Objects 13
3 Object-Observer Geometry with PI ume 17
4 Five Basic Situations in Which Air Pollution is
Visually Perceptible 20
5 Plan View of Observer-Plume Geometry 28
6 Elevation View of Observer-Plume Geometry 29
7 Plan View of Four Possible Plume Parcel Trajectories
That Would Transport Emissions from a Source to Affect
a Vista in a Class I Area 34
8 Example of a Frequency Distribution of Visual Impact 37
9 Schematic Diagram Showing Plume-Observer Geometry for Two
Wind Directions 41
10 Two Types of Plume Visibility Impairment Considered in
the Level-1 Visibility Screening Analysis 48
11 Geometry of Plume, Observer, and Line of Sight Used in
Level-1 Visibility Screening Analysis 48
12 Vertical Dispersion Coefficient (o^) as a Function of
Downwind Distance from the Source 57
13 Regional Background Visual Range Values (rv(j) for Use in
Level-1 Visibility Screening Analysis 59
14 Example of Map Showing Emissions Source, Class I Areas,
and Stable Plume Trajectories 69
vm
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15 Examples of Terrain Elevation Plots 70
16 Joint Frequency Distribution Tables Required to Esti-
mate Worst-Case Meteorological Conditions for Plume
Discoloration 75
17 Schematic Diagram Showing Emissions Source, Observer
Locations, and Wind Direction Sectors , 1 77
18 Joint Frequency Distribution Tables Required to Estimate
Worst-Case Meteorological Conditions for Visibility
Impairment Due to S02 Emissions 83
19 Example Map Showing Class I Areas in Region Around
Emissions Source and Wind Direction/Speed Sectors 86
20 A Schematic of the Vertical 03 Structure and Its Diurnal
and Seasonal Variations at Remote Sites „... 90
21 Locus of Plume Centerlines within Worst-Case Wind
Direction Sector 94
22 Observer-Plume Orientation for Level-2 Visibility
Screening Analysis 96
23 Plan View of Assumed Plume-Observer Geometry for Level-2
Visibility Screening Calculations 93
24 Scattering-to-Volume Ratios for Various Size
Distributions 101
25 Wavelength Dependence of Light Absorption of Nitrogen
Dioxide 108
26 Phase Functions for Various Particle Size
Distributions 113
27 Logic Flow Diagram for Level-1 Analysis 123
28 Logic Flow Diagram for Level-2 Analysis 124
29 Examples of Predicted Frequency of Occurrence of Plume
Discoloration Perceptible from a Class I Area: Number
of Mornings in the Designated Season with an Impact
Greater than the Indicated Value 134
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30 Examples of Predicted Frequency of Occurrence of Haze
(Visual Range Reduction) in a Class I Area: Number
of Afternoons in the Desginated Season with an Impact
Greater than the Indicated Value 135
31 Examples of Calculated Plume Visibility Impairment
Dependent on Wind Direction, Azimuth of Line of Sight,
and Viewing Background 136
32 Example of Black and White Plume-Terrain Perspective 142
A-l Two Types of Spatial Distributions of Extra Extinction 151
A-2 Change in Sky/Terrain Contrast as a Function of
Fractional Increase in Extinction Coefficient for
Various Observer-Terrain Distances v. , 157
A-3 Change in Sky/Terrain Contrast as a Function of
Fractional Decrease in Visual Range for Various v v
Observer-Terrain Distances 158
A-4 Change in Sky/Terrain Contrast as a Function of Plume
Optical Thickness for Various Observer-Terrain Distances 159
E-l Relative Location of the Proposed Power Plant and Class I
Area for Example 1 324
E-2 Significant Terrain Features and Possible
Plume Trajectories 329
E-3 Terrain Elevation Plots 330
E-4 Class I Areas within 48-Hour Transport Range at Wind
Speeds up to 8 m/s 333
E-5 Worksheet for the Calculation of Wind Speed and Mixing
Depth Joint Frequency Distribution 335
E-6 Observer-Plume Orientations 337
E-7 Plan View of Assumed Geometries for Views 1 and 2 338
E-8 Plan View of Assumed Geometry for View 3 339
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TABLES
1 Example Table Showing Worst-Case Meteorological
Conditions for Plume Discoloration Calculations 78
2 Example Table Showing Worst-Case Limited Mixing
Conditions for Haze Calculations 84
3 Example Tables Showing Computations of Days in a Five-
Year Period with the Given Limited Mixing Condition 88
4 Wavelength Dependence of Scattering Coefficient as
a Function of Particle Size Distribution 104
5 Example Table Showing Background Atmosphere Phase
Functions and Scattering Coefficients 116
6 Example Summary of the Frequency of Occurrence of
Power Plant Plume Discoloration Perceptible from a
Class I Area 139
7 Example Summary of Frequency of Occurrence of Increased
Haze (Visual Range Reduction) in a Class I Area Due to
Power Plant Emissions 140
A-l Summary of Relationships among Parameters Used for
Quantifying Increased Atmospheric Haze 160
E-l Frequency of Occurrence of SW and WSW Winds by
Dispersion Condition and Time of Day 332
E-2 Frequency of Episode Days by Mixing Depth and Wind Speed 334
E-3 Values of 0^- 343
E-4 Phase Functions and Scattering Coefficients for
Background and PIume 351
xi
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E-5 Comparison-of Example Power Plant Emissions and
Appendix D Power Plant Emissions 357
E-6 Comparison of Selected Scenario Descriptors 357
E-7 Example 2--Cement Plant and Related Operations 360
E-8 Background and Plume atmosphere Phase Functions and
Scattering Coefficients 368
E-9 Projected Plume Contrast and Contrast Reduction
for Example 2 370
xi i
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NOMENCLATURE
A — Azimuth angle of line of sight, relative to north
babs -- Light absorption coefficient of the air parcel, propor-
tional to concentrations of nitrogen dioxide (NC^) and
aerosol (like soot) that absorb visible radiation (m~l)
bext — Light extinction coefficient of an air parcel, the sum of
absorption and scattering coefficients (m"*)
bR — Light scattering coefficient of particle-free air caused
by Rayleigh scatter from air molecules (m~^)
^scat — Light scattering coefficient resulting from Rayleigh
scatter (air molecules) and Mie scatter (particles), the
sum of bR and bsp (m"*)
(bscat/V) — Light scattering efficiency per unit aerosol volume con-
centration (m
bs_ -- Light scattering coefficient caused by particles only
(m'1)
C — Contract at a given wavelength of two colored objects,
like plume/sky or sky/terrain
Chaze -- Contrast of a haze layer against the sky above it
Cml-n — Contrast that is just perceptible, a threshold contrast
Cpiunie -- Contrast of a plume against a viewing background like the
sky on a terrain feature
Cr — Contrast of a terrain feature at distance r against the
sky
ACr -- Change in sky/terrain contrast caused by a plume or extra
extinction
CQ — Intrinsic contrast of a terrain feature against the sky.
The sky /terrain contrast at r = 0. For a black object,
xiii
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D -- Stack diameter (m)
AE(L*a*b*) — Color difference parameter used to characterize the per-
ceptibility of the difference between two colors. In the
context of this workbook, it is used to characterize the
perceptibility of a plume on the basis of the color dif-
ference between the plume and a viewing background like
the sky, a cloud, or a terrain feature. Color differences
are due to differences in three dimensions: brightness
(L*) and color hue and saturation (a*b*)
F -- Buoyancy flux of flue gas emissions from a stack (m4s"^)
Fs -- Solar insolation or flux incident on an air parcel within
a given wavelength band (watt m~ u
fobj "" Fractlon °f total plume optical thickness between an
observer and a viewed object
g -- Gravitational acceleration (=9.8 m s"^)
H — Plume altitude above the ground (m)
Hm — Height of a mixed layer above the ground (m)
"stack "~ Hei9nt of a stack (m)
Ah -- Plume rise (m)
I — Light intensity or radiance for a given line of sight and
wavelength band (watt m'^sr'^un'M- Subscripts t and h
refer to terrain and horizon, respectively.
I0tjj — Light intensity reflected from an object like a terrain
feature (watt m"^sr~^un~^)
kd — Rate constant for surface deposition (s~*)
kf -- Rate constant for S02-to-S04= conversion (s~*)
p — Atmospheric dispersion parameter used in the level-1
analysis to calculate the horizontal line-of-sight
integral of a plume concentration (s m"^)
p(X,Q) — Phase function, a parameter that relates the portion of
total scattered light of a given wavelength X that is
scattered in a given direction specified by the scattering
angle 0
xiv
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Q — Emission rate of a species, such as S02, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
' Qscat "" p^ume flux °f tne scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH ~ Relative background humidity (percent)
r — Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp — Distance from observer to centroid of plume material (m)
rq — Distance from viewed object to centroid of plume material
(m)
rv -- Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rVQ -- Background visual range without plume (m)
T -- Temperature in degrees absolute
t -- Time (s)
u — Wind speed (m s~*)
$ -- Flue gas volumetric flow rate (rn^s'l)
v -- Wind velocity vector (m s~*)
AV-- Percentage visual range reduction
Vj — Deposition velocity (m s~*)
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
zsite "" Elevation of a site above mean sea level (m)
xv
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1 . , ._ Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p -- Density of a particle (g m~^)
a — Horizontal angle between a line of sight and the plume
centerline
3 — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m"^)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, NC^)
[ ] — Denotes the concentration of the species within brackets
ui — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
6 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 6 would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
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Q — Emission rate of a species, such as S02» or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s"^). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
• Qscat — Plume flux of the scattering coefficient above background
'l). Subscripts refer to species considered (e.g.,
, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r — Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
r« -- Distance from observer to centroid of plume material (m)
rq — Distance from viewed object to centroid of plume material
(m)
ry -- Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rvg -- Background visual range without plume (m)
T — Temperature in degrees absolute
t -- Time (s)
u — Wind speed (m s"*)
v1 — Flue gas volumetric flow rate (m^s"^)
v -- Wind velocity vector (m s~*)
AV-- Percentage visual range reduction
vd — Deposition velocity (m s~*)
WD — Wind direction
x — Downwind distance from emissions source (m)
y ~ Cross-wind direction from plume centerline (m)
" Elevation of a site above mean sea level (m)
xv
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zbl k "" Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z « Distance above ground (m)
X — Wavelength of light (m)
p — Density of a particle (g m~3)
a — Horizontal angle between a line of sight and the plume
centerline
3 __ Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m~3)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] — Denotes the concentration of the species within brackets
w — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
0 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 6 would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
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Q — Emission rate of a species, such as SC^, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s"*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
-- Plume flux of the scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
r« -- Distance from observer to centroid of plume material (m)
rq -- Distance from viewed object to centroid of plume material
(m)
ry — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
ryg -- Background visual range without plume (m)
T -- Temperature in degrees absolute
t — Time (s)
u — Wind speed (m s"*)
v* -- Flue gas volumetric flow rate (m^s**)
v -- Wind velocity vector (m s~*)
AV-- Percentage visual range reduction
vd -- Deposition velocity (m s"M
WD — Wind direction
x -- Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
— Elevation of a site above mean sea level (m)
xv
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I . . __. Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs — Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z ~ Distance above ground (m)
X -- Wavelength of light (m)
p — Density of a particle (g m"3)
a — Horizontal angle between a line of sight and the plume
center!ine
3 — Vertical angle between a line of sight and the horizontal
X — Concentration of a given species in an air parcel (g nf3)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, SC^*, NOg)
[ ] — Denotes the concentration of the species within brackets
w — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
9 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 6 would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
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Q — Emission rate of a species, such as S02, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
Qscat ~" p^ume ^ux °f tne scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp ~ Distance from observer to centroid of plume material (m)
rq -- Distance from viewed object to centroid of plume material
(m)
ry — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rVQ — Background visual range without plume (m)
T — Temperature in degrees absolute
t — Time (s)
u -- Wind speed (m s~*)
$ — Flue gas volumetric flow rate (m^s'M
v -- Wind velocity vector (m s'^)
AV— Percentage visual range reduction
vd -- Deposition velocity (m s"*)
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
zsite "" Elevation of a site above mean sea level (m)
xv
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1 . . .. Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs — Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p — Density of a particle (g m"3)
a __ Horizontal angle between a line of sight and the plume
centerline
B — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m"3)
T -- Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] — Denotes the concentration of the species within brackets
ID — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
9 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 8 would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
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Q ~ Emission rate of a species, such as S02» or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
Qscat "" ?^me ^ux °f tne scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp — Distance from observer to centroid of plume material (m)
rq -- Distance from viewed object to centroid of plume material
(m)
rv — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rv0 -- Background visual range without plume (m)
T — Temperature in degrees absplute
t -- Time (s)
u — Wind speed (m s~*)
$ -- Flue gas volumetric flow rate (m^s"*)
v — Wind velocity vector (m s~*)
AV— Percentage visual range reduction
vd -- Deposition velocity (m s"M
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
"" Elevation of a site above mean sea level (m)
xv
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I . — Elevation of the terrain above mean sea level that can be
D IOCK
assumed to block the flow of emissions (m)
Z — Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p — Density of a particle (g m'3)
a-- Horizontal angle between a line of sight and the plume
centerline
0 — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m"3)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, NC^)
[ ] — Denotes the concentration of the species within brackets
a) — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
e — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 9 would equal 0°. If the observer
looked away from the sun, 9 would equal 180°.
xvi
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Q — Emission rate of a species, such as S02, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s"^). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
• Qscat — Plume flux of the scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
r- — Distance from observer to centroid of plume material (m)
rq — Distance from viewed object to centroid of plume material
(m)
rv -- Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
ryQ -- Background visual range without plume (m)
T -- Temperature in degrees absolute
t — Time (s)
u — Wind speed (m s~*)
$ — Flue gas volumetric flow rate (m^s"*)
v -- Wind velocity vector (m s"^)
AV-- Percentage visual range reduction
vd -- Deposition velocity (m s~*)
WD — Wind direction
x -- Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
" Elevatl'on of a site above mean sea level (m)
xv
-------
I , __ Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X— Wavelength of light (m)
p — Density of a particle (g m~3)
a — Horizontal angle between a line of sight and the plume
centerline
3 — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m"^)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, Nl^)
[ ] — Denotes the concentration of the species within brackets
CD — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
9 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 6 would equal 0°. If the observer
looked away from the sun, 9 would equal 180°.
xv i
-------
Q — Emission rate of a species, such as SC^, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
ux °f the scattering coefficient above background
Subscripts refer to species considered (e.g.,
SC>4=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp — Distance from observer to centroid of plume material (m)
rq -- Distance from viewed object to centroid of plume material
(m)
•
ry — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
ryg -- Background visual range without plume (m)
T -- Temperature in degrees absolute
t — Time (s)
u — Wind speed (m s~*)
tf -- Flue gas volumetric flow rate (m^s"*)
v -- Wind velocity vector (m s~*)
AV-- Percentage visual range reduction
vd -- Deposition velocity (m s~*)
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
zsite ~~ Elevation of a site above mean sea level (m)
xv
-------
I . __ Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs — Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p — Density of a particle (g m"^)
a — Horizontal angle between a line of sight and the plume
centerline
3 — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m~^)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] — Denotes the concentration of the species within brackets
ID — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
e — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 6 would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
-------
Q — Emission rate of a species, such as S02, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, 504% and particulate)
Qscat — Plume flux of the scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r -- Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp — Distance from observer to centroid of plume material (m)
rq — Distance from viewed object to centroid of plume material
(m)
rv — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rvg — Background visual range without plume (m)
T — Temperature in degrees absolute
t — Time (s)
u — Wind speed (m s~*)
tf -- Flue gas volumetric flow rate (m^s~M
v -- Wind velocity vector (m s"^)
AV-- Percentage visual range reduction
vd -- Deposition velocity (m s"M
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume center line (m)
zsite "" Elevation of a site above mean sea level (m)
xv
-------
. __ Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Z -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p — Density of a particle (g m"3)
a— Horizontal angle between a line of sight and the plume
centerline
3 ._ Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m"3)
T -- Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] — Denotes the concentration of the species within brackets
-------
Q -- Emission rate of a species, such as S02» or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
gscat -- Plume flux of the scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
S04=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH — Relative background humidity (percent)
r — Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
r_ — Distance from observer to centroid of plume material (m)
r- — Distance from viewed object to centroid of plume material
(m)
rv — Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rVQ -- Background visual range without plume (m)
T — Temperature in degrees absolute
t -- Time (s)
u — Wind speed (m s~*)
$ -- Flue gas volumetric flow rate (nrs~*)
v — Wind velocity vector (m s"*)
AV— Percentage visual range reduction
vd -- Deposition velocity (m s~*)
WD — Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume centerline (m)
zsite "" Elevation of a site above mean sea level (m)
xv
-------
1 . . __ Elevation of the terrain above mean sea level that can be
assumed to block the flow of emissions (m)
Zs -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X ~ Wavelength of light (m)
p — Density of a particle (g m"3)
a— Horizontal angle between a line of sight and the plume
centerline
3 — Vertical angle between a line of sight and the horizontal
x ~ Concentration of a given species in an air parcel (g m~3)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] — Denotes the concentration of the species within brackets
a) — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
8 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, 9 would equal 0°. If the observer
looked away from the sun, 9 would equal 180°.
xvi
-------
Q — Emission rate of a species, such as S02, or plume flux at
a given downwind distance, which may be less than the
emission rate because of surface deposition and chemical
conversion (g s~*). Subscripts refer to species con-
sidered (e.g., S02, S04=, and particulate)
Qscat "" P^ume flux °f tne scattering coefficient above background
(m^s'l). Subscripts refer to species considered (e.g.,
SC>4=, primary particulate)
R -- Blue-red ratio used in visibility impairment calculations
to characterize the coloration of a plume relative to the
viewing background
RH -- Relative background humidity (percent)
r — Distance along the line of sight from the viewed object to
the observer (m)
rQ -- Object-observer distance (m)
rp — Distance from observer to centroid of plume material (m)
rq -- Distance from viewed object to centroid of plume material
(m)
ry -- Visual range, a parameter characteristic of the clarity of
the atmosphere, inversely proportional to the extinction
coefficient. H is farthest distance at which a black
object is perceptible against the horizon sky (m)
rVQ -- Background visual range without plume (m)
I -- Temperature in degrees absolute
t -- Time (s)
u — Wind speed (m s~^)
tf -- Flue gas volumetric flow rate (m^s"*)
v -- Wind velocity vector (m s"*)
AV-- Percentage visual range reduction
vd -- Deposition velocity (m s~*)
WD ~ Wind direction
x — Downwind distance from emissions source (m)
y — Cross-wind direction from plume center line (m)
zsite "" Elevation of a site above mean sea level (m)
xv
-------
I . _. Elevation of the terrain above mean sea level that can be
D.IOCK i
assumed to block the flow of emissions (m)
Zs -- Solar zenith angle, the angle between the sun and the
normal to the earth's surface
z — Distance above ground (m)
X — Wavelength of light (m)
p -- Density of a particle (g m~3)
a— Horizontal angle between a line of sight and the plume
centerline
p — Vertical angle between a line of sight and the horizontal
x — Concentration of a given species in an air parcel (g m~^)
T — Optical thickness of a plume, the line-of-sight integral
of the extinction coefficient. Subscripts refer to the
component of the total or plume optical thickness (e.g.,
particulate, S04=, N02)
[ ] « Denotes the concentration of the species within brackets
u — Albedo of the plume or background atmosphere, the ratio of
the scattering coefficient to the extinction coefficient
9 — Scattering angle, the angle between direct solar radiation
and the line of sight. If the observer were looking
directly at the sun, e would equal 0°. If the observer
looked away from the sun, 6 would equal 180°.
xvi
-------
INTRODUCTION
The Clean Air Act Amendments of 1977 require evaluation of new and
existing emissions sources to determine potential impacts on visibility in
class I areas.* These source evaluations are to be used as part of a
regulatory program to prevent future and remedy existing impairment of
visibility in mandatory class I federal areas that results from man-made
air pollution.
This workbook is designed to provide the air pollution analyst with
technical guidance in determining the potential impacts of an emissions
source on class I area visibility. It should be useful in siting studies,
emissions control specification, environmental impact statements, and new
source reviews, and it may also be used in conjunction with measurements
of existing emissions sources to assess the potential requirements for
emissions control retrofit technology. It is beyond the scope of this
document to address the cumulative impacts of multiple sources on regional
haze. Rather, the emphasis is on the incremental visual impact of a
single emissions source.
Although this workbook can be used independently, we highly recommend
that the analyst read the following documents:
> U.S. Environmental Protection Agency (October 1979),
"Protecting Visibility: An EPA Report to Congress," EPA-
450/5-79-008, U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina.
> Latimer, D. A., et al. (September 1978), "The Development
of Mathematical Models for the Prediction of Anthropogenic
Visibility Impairment," EPA-450/3-78-110a,b,c, U.S.
Class I area as used in this document means Federal Class I area.
1
-------
Environmental Protection Agency, Research Triangle Park,
North Carolina.
> Turner, D. B. (1969), "Workbook of Atmospheric Dispersion
Other guidance documents on visibility, including those below,
should also be consulted:
> User's Manual for the Plume Visibility Model (PLUVUE),
EPA-450/4-30-032.
> Interim Guidance for Visibility Monitoring, EPA-450/2-80-082
> Guidelines for Determining Best Available Retrofit Technology
for Coal-Fired Power Plants and Other Major Stationary Sources,
EPA-450/3-80-0096.
1.1 CLASSES OF VISIBILITY IMPAIRMENT
Two separate classes of visibility impairment are of concern in this
workbook:
> Atmospheric discoloration.
> Visual range reduction (increased haze).
Plumes from power plants or other combustion sources may be discol-
ored because of NOX emissions that are converted in the atmosphere to the
reddish-brown gas, nitrogen dioxide. However, particle emissions and sec-
ondary aerosols formed from gaseous precursor emissions may also discolor
the atmosphere. Increased haze is caused principally by primary particu-
late emissions and secondary aerosols, such as sulfate.
Worst-case impacts associated with these two classes of visibility
impairment occur during two distinctly different kinds of atmospheric con-
ditions. On one hand, atmospheric discoloration is greatest during
periods of stable, light winds that occur after periods of nighttime
transport. These conditions result in maximum particle and N02 line-of-
-------
sight integrals that could cause maximum plume coloration. However,
because a plume remains intact during such conditions, discoloration would
be limited to a shallow vertical layer in the atmosphere. General atmos-
pheric clarity would not be impaired, but the plume or layer could have an
adverse visual impact, degrading the scenic beauty of a vi$ta. The plume
might be perceptible and discolored enough to interfere with a visitor's
enjoyment of a class I area.
On the other other hand, increased general haze (decreased visual
range) is greatest during light wind, limited mixing, or stagnation condi-
tions after daytime transport, because conversion of gaseous precursor
emissions to secondary aerosol is more rapid during these conditions, when
an individual plume or discolored layer may not be perceptible at all.
Rather, the impact would be manifested by an increased haze and loss of
clarity in landscape features. Also, since the impact of any one emis-
sions source may be small when compared to regional emissions, incremental
impacts must be considered in light of the magnitude and frequency of
increased haze caused by other natural and man-made emissions sources in
the region. Increased haze may be a particularly severe problem in areas
where ventilation is limited by terrain obstacles such as canyon walls,
mountain ranges, plateaus, and river valleys. In such areas, emissions
could accumulate over a period of a few days. Diurnal upslope and down-
slope (drainage) winds can cause a "sloshing" air motion that could trap
emissions in a valley. Although ground-level contaminant concentrations
might be very low in such a situation, increased haze could be a problem.
EPA has published regulations concerning the protection of visibility
as Subpart P of Part 51 Title 40 of the Code of Federal Regulations.
Tie regulations define "visibility impairment" to mean any humanly
perceptible change in visibility (visual range, contrast, coloration)
f -oni that which would have existed under natural conditions. Definitions
for "adverse impact on visibility" and "significant impairment" are also
provided tn the regulations. States are required to establish pro-
cedures for use in conducting visibility impact analyses. An important
part of a visibility impact analysis is to determine the
-------
frequency of occurrence and magnitude of visual impact in or within view
of a class I area.
1.2 APPROACH USED IN THIS WORKBOOK
This workbook outlines a screening procedure that will expedite the
analysis of an emissions source. Figure 1 shows a schematic diagram of
this screening procedure. Potentially, one could analyze a given source
at any one of three basic levels of detail. A level-1 analysis involves a
series of conservative screening tests that permit the analyst to elimi-
nate sources with little potential for adverse or significant visibility
impairment. A simple screening calculation, requiring only a few minutes
of an analyst's time, indicates whether a source could cause significant
impairment during hypothetical, worst-case meteorological conditions. If
not, further analysis is unnecessary. If impairment is indicated, a
level-2 analysis would be performed. The level-2 screening procedure is
similar to the level-1 analysis in that its purpose is to estimate impacts
during worst-case meteorological conditions; however, more specific infor-
mation regarding the source, topography, regional visual range, and mete-
orological conditions is assumed to be available. A frequency-of-occur-
rence analysis is performed to determine conditions representative of the
worst day in a year. Whereas the level-1 analysis requires only a few
minutes, the level-2 analysis may require several days. In this workbook
several options are recommended for performing a level-2 analysis: (1)
use of hand calculations based on the formulas, tables, and graphs pre-
sented here, (2) use of reference tables and figures presented in the
appendixes, and (3) use of the computer-based plume visibility model.
Finally, if both the level-1 and level-2 analyses indicate the possi-
bility of significant or adverse visibility impairment, a more detailed
It is Important to note that emissions may not have to be transported
into a class I area to cause visual impact 1n a class 1 area. If a
vista within a class I area has views of landscape features outside that
area that are considered by the federal land manager to be an integral
part of the class I area experience, that vista may be protected.
-------
LEVEL-1
ANALYSIS^
A« TESTS
INPUT :
• NOX. S02. PARTICULATE
EMISSIONS
• REGIONAL VISUAL RANGE
• DISTANCE TO CLASS I AREA
CALCULATE CONTRAST VALUES
}• C2» AND t3 BAbtU UN
WORST-CASE ASSUMPTIONS
I
NO
ADVERSE OR
SIGNIFICANT
VISIBILITY IM
PAIRMENT
LIKELY
Yes
LEVEL-2
ANALYSIS <
AND TESTS
INPUT:
• SIZE DISTRIBUTION
• METEOROLOGICAL DATA
• TOPOGRAPHY
• AMBIENT DATA
CA
IM
AR
OF
_C
'A
:A
Tl
*
JLATE WORST-DAY VISUAl
:TS BASED ON ACTUAL
CONDITIONS USING ONE
<£ FOLLOWING:
HAND CALCULATIONS
REFERENCE TABLES
REFERENCE FIGURES
COMPUTER MODEL
ARE
VISUAL
IMPACT PARAM-
ETERS GREATER
THAN CRITERIA
VALUES?
NO
ADVERSE OR
SIGNIFICANT
VISIBILITY IM
PAIRMENT
LIKELY
LEVEL.3
ANALYSIS <
AND TESTS
INPUT:
• JOINT FREQUENCIES OF
WIND SPEED. HIND DIR-
ECTION. STABILITY,
MIXING DEPTH, AND
BACKGROUND OZONE CON-
CENTRATION AND VISUAL
RANGE
1 YES
CALCULATE MAGNITUDE AND
FREQUENCY OF OCCURRENCE
Ur VISUAL InrACI Ualnu
MODELS. DATA, AND
OTHER TECHNIQUES
1
IS
IMPACT
JUDGED ADVERSE
OR SIGNIFICANT
BY GOVERN-
MENT?
VISUAL
IMPACT IS
NOT JUDGED TO
BE ADVERSE OR
SIGNIFICANT
VISUAL
IMPACT IS
JUDGED TO
BE ADVERSE OR
SIGNIFICANT
ANALYZE ALTERNATIVES:
• BETTER EMISSIONS CONTROLS
• ALTERNATIVE SITES
• SCALED-DOWN SOURCE SIZE
• CANCEL PLANS FOR SOURCE
Figure 1. Schematic of visibility screening analysis procedure. The
numerical meaning of the terms "significant" and "adverse"
differ on a case-by-case basis and will be defined after
an in-depth policy analysis of each case-
-------
level-3 analysis is recommended. The purpose of a level-3 analysis is to
provide an accurate description of the magnitude and frequency of occur-
rence of impact. For this level of analysis, a visibility model is
used. The number of days per year and season in which a given magnitude
of impact occurs are calculated from joint frequency tables of wind speed,
wind direction, stability, mixing depth, ozone concentration, and visual
range in the area. Computer graphics can be used to display the
appearance of plumes or haze layers in black and white or in color.
Detailed analyses of the spatial and temporal distribution of windfields
and the effect on visual impacts may be made. For existing sources,
measurements of visual impacts can be used in place of, or in combination
with, the model calculations.
As shown in figure 1, there are tests that the analyst can apply
after the level-1 and level-2 analyses to determine if there is a
potential for adverse or significant impairment. If these tests show
little potential for adverse or significant impacts, the analyst may
choose to make a recommendation on the basis of these less detailed
analyses. In some situations, however, even though the level-1 or level-2
test shows that impacts are not likely to be adverse or significant, the
analyst may choose to use more detailed analytic procedures such as those
suggested for the level-3 analysis. This might be the case if the emis-
sions source barely passes the level-1 or level-2 test. Also, special
meteorological conditions such as stagnation, terrain-influenced disper-
sion, and complex photochemistry (if the source emits reactive hydro-
carbons, is located in an urban area, or is affected by an urban plume)
may require further detailed analysis.
We have attempted to make this workbook a straightforward, easy-to-
use reference manual; however, before we present the details of the visi-
bility screening analysis procedures, we feel it is necessary to describe
some of the concepts and theories upon which they are based. These are
presented in chapter 2. The level-1 and level-2 analyses and tests are
presented in chapters 3 and 4. Suggestions for more detailed analyses
(level-3) are presented in chapter 5.
-------
GENERAL CONCEPTS
In this chapter we present the general conceptual approach used
throughout this workbook. We recommend that the user of this document
read this chapter and the reference material cited in chapter 1 before
using the procedures presented in the following three chapters for the
level-1, -2, and -3 visibility screening analyses. Here we discuss the
following subjects:
> Atmospheric optics and visibility impairment.
> Plume-observer geometry.
> Characterization of the frequency of occurrence of visual
impacts.
2.1 PHYSICAL CONCEPTS RELATED TO VISIBILITY IMPAIRMENT
2.1.1 Visual Perception
Human visual perception occurs when the eye is exposed to light
(i.e., electromagnetic radiation within the visible spectrum, 0.4 to
0.7 urn). Furthermore, the eye must be exposed to light of different
intensities or wavelength mixtures before one perceives objects in the
outside world. Since objects are usually viewed through the atmosphere
(unless the observer is under water or in outer space), atmospheric con-
taminants can affect what one perceives visually. This is the crux of the
visibility impairment issue: what impact does air pollution have on our
visual perception, particularly of scenic areas?
Through recent perceptual research, Land (1977) has found that the
eye-brain mechanism responds to objects within the field of view using a
-------
comparison procedure. We compare light intensities of different objects
at different wavelengths in the visual field. Through this comparison we
perceive whether an object is visible, whether it is lighter or darker
than neighboring objects, and whether it is more or less blue, green, or
red than neighboring objects. A convenient way to describe this light
intensity comparison is by a ratio such as
where Ij and Ig are the spectral radiances (light intensities) of two
objects, 1 arid 2, at wavelength X in the visible spectrum (0.4 < X < 0.7
vm).
Another way to describe this comparison of light intensities is to
use contrast:
I2(X) MX)
Note that if C(x) =0 for all wavelengths X, then Ij « I2 and there
would be no perceptible difference in the two objects defined by Ij and
\2> When we say there is much contrast in a given scene, then at least
for some wavelengths, C(x) * 0. Air pollution is visually perceptible
only if it changes the contrast of objects at different wavelengths in the
visible spectrum.
2-1.2 Fundamental Causes of Visibility Impairment
The effects of air pollution are visually perceptible as a result of
the following interactions in the atmosphere:
8
-------
> Light scattering
- By molecules of air
- By particles
> Light absorption
- By gases
- By particles.
Light scattering by gaseous molecules of air (Rayleigh scattering),
which causes the blue color of the atmosphere, is dominant when the air is
relatively free of aerosols and light-absorbing gases. Light scattering
by particles is the most important cause of visual range reduction. Fine
solid or liquid particulates, whose diameters range from 0.1 to 1.0 yn,
are most effective per unit mass in scattering light.
Light absorption by gases is particularly important in the discussion
of anthropogenic visibility impairment since nitrogen dioxide, a major
constituent of power plant plumes, absorbs light. Nitrogen dioxide is
reddish-brown because it absorbs strongly at the blue end of the visible
spectrum while allowing light at the red end to pass through. Light
absorption by particles is important when black soot (finely divided
carbon) is present.
Anthropogenic contributions to visibility impairment result from the
emission of primary particulate matter (such as fly ash, acid and water
droplets, soot, and fugitive dust) and of pollutant precursors that are
converted in the atmosphere into the following secondary species:
> Nitrogen dioxide (N02) gas from emissions of nitric oxide
(NO).
> Sulfate (S0^=) particles from SOX emissions.
> Nitrate (N03~) particles from NOX emissions.
> Organic particles from hydrocarbon emissions.
Before particulate control technology was commonly employed, primary
particulate matter, such as smoke, windblown dust, or soot, was a major
-------
contributor to visibility impairment, because emissions sources emit pri-
mary particles of fly ash and combustion-generated particulates to the
atmosphere. If such sources are equipped with efficient abatement equip-
ment, the emission rate of primary particles may be small. However, some
emissions escape the control equipment and do contribute to the ambient
particulate concentration and hence to general visibility impairment. If
the emission rate of primary particulates is sufficiently large, the plume
itself may be visible.
In the past, many older emissions sources generated conspicuous,
visible plumes resulting from the large emission rates of primary par-
ticulate matter. New plants and old plants still in operation have bene-
fited from more efficient particulate abatement equipment and a state of
the art in which particulate removal efficiencies in excess of 99.5
percent are commonly specified and achieved. In addition, with the
installation of flue gas desulfurization systems (scrubbers), and with
combustion modifications, sulfur dioxide and nitrogen oxide emissions have
also been reduced. As a result, the visual impact of emissions has been
sharply reduced, as evidenced by the nearly invisible plumes under most
conditions of modern coal-fired power plants. Unfortunately, however, the
contribution to visibility impairment of the secondary pollutants—
nitrogen dioxide gas and sulfate, nitrate, and organic aerosol--!s now
becoming increasingly evident and is of growing concern.
Since nitrogen dioxide absorbs light selectively, it can discolor the
atmosphere, causing a yellow or brown plume when present in sufficient
concentrations. Almost all of the nitrogen oxide emitted from emissions
sources is nitric oxide, a colorless gas. But chemical reactions in the
atmosphere can oxidize a substantial portion of the colorless NO to the
reddish-brown N02.
Secondary sulfate, nitrate, and organic particles have a dominating
effect on visual range in many situations because these particles range in
size from 0.1 to 1.0 un in diameter, which is the most efficient size per
unit mass for light scattering. As is discussed later, submicron aerosol
10
-------
(with diameters in the range from 0.1 to 1.0 nn) is 10 times more effec-
tive in light scattering than the same mass of coarse (> 1 un) aerosol.
Also, because secondary aerosol forms slowly in the atmosphere, maximum
aerosol concentrations and associated visibility impairment may occur at
large distances from emissions sources.
2.1.3 Atmospheric Optics
The effect of the intervening atmosphere on the visibility and
coloration of a viewed object (e.g., the horizon sky, a mountain, a cloud)
can be calculated by solving the radiation transfer equation along the
line of sight. As we noted earlier, the effects of air pollution are
visually perceptible because of contrast. Thus, visibility impairment can
be quantified by comparing the intensity or the coloration of two objects
(e.g., a distant mountain against the horizon sky). The effect of the
intervening atmosphere on the light intensity of the viewed object can be
determined if the concentration and characteristics of air molecules,
aerosol, and nitrogen dioxide are known along the line of sight.
The change in spectral light intensity or spectral radiance I(X) as a
function of distance along the sight path at any point in the atmosphere
can be calculated (neglecting multiple scattering ) as follows:
(l)
Uj
dr
Multiple scattered radiation is scattered (or reflected) more than
once. Although the plume visibility model treats multiple scattering,
U is Beyond the scope of the hand calculations presented in this
workbook to do so. Reasonably accurate solutions are obtained for the
contrast parameters used to characterize visibility impairment in this
workbook even if multiple scattering is ignored.
11
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where
r = the distance along the sight path from the object
to the observer,
p(0) = the scattering distribution or phase function for
scattering angle e [see figure 2(a) for defini-
tions],
Fs = the solar flux (watt/nr/un) incident on the
atmosphere,
bscat = the scattering coefficient, which is the sum of
the Rayleigh scattering (due to air molecules),
b^, and the scattering due to particles, bsp:
bext = the sum °^ tne scattering, bsp, and absorption
coefficients, babs:
On the right-hand side of equation (1), the first term represents
light absorbed or scattered out of the line of sight; the second term
represents light scattered into the line of sight. The values of bscat
and babs can be evaluated if the aerosol and N02 concentrations and such
characteristics as the refractive index and the size distribution of the
aerosol are known. Except in the cleanest atmospheres, bscat is dominated
by bsp; also, unless soot is present, babs is dominated by the absorption
coefficient due to N02. Scattering and absorption are wavelength-
dependent, and effects are greatest at the blue end (X= 0.4 un) of the
visible spectrum (0.4 < X < 0.7 im). The Rayleigh scattering coefficient
bR is proportional to X'4; the scattering coefficient caused by particles
is generally proportional to X"n, where 0 < n < 2. Also, N02 absorption
is greatest at the blue end. This wavelength dependence causes the dis-
coloration of the atmosphere.
12
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SUN
SCATTERING
ANGLE e
OBJECT
ELEMENTAL VOLUME
(CONTAINING AIR,
PARTICLES, AND N02)
/LINE OF SIGHT
—
VI + dl
OBSERVER
(a) Geometry
LIGHT INTENSITY OF HORIZON
Object-Observer Distance rQ
»
(b) Visual Range r (Homogeneous Atmosphere)
Figure 2. Effect of an atmosphere on the perceived light
intensity of objects.
13
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For a uniform atmosphere, without inhomogeneities caused by plumes
(where b - t and bext do not vary with distance r along the line of
sight), equation (1) can be solved to find the intensity and coloration of
the horizon sky (neglecting multiple scattering):
T
h
The perceived intensity of distant bright and dark objects will approach
this intensity as an asymptote, as illustrated by figure 2(b).
The visual range rv is the distance at which a black object is barely
perceptible against the horizon sky, which occurs when the perceived light
intensity of the black object is (1 + Cmin)Ih, where Cmin is the liminal
(barely perceptible) contrast, commonly assumed to be -0.02. When
equation (1) is solved for rv, for a uniform atmosphere, rv is independent
of p(0) and FS(X) and can be calculated'using Koschmieder's equation:
„ _ in 3.912
"""
where bext(x) is evaluated at the middle of the visible spectrum (to which
the human eye is most sensitive) and where X = 0.55 un. The visual range
for a nonuniform atmosphere (e.g., a plume case) must be calculated by
evaluating equation (1) for the appropriate conditions of the given situa-
tion.
Atmospheric coloration is determined by the wavelength-dependent
scattering and absorption in the atmosphere. -The spectral distribution of
I(X) for X over the visible spectrum determines the perceived color and
light intensity of the viewed object. The relative contributions of scat-
tering (aerosols plus air) and absorption (N02) to coloration can be
illustrated by rearranging equation (1):
-------
. * .
~ bscat(x)
- 1
(6)
Note from equation (4) that when light absorption is negligible com-
pared witfi light scattering, the clear horizon intensity is simply (if
multiple scattering is ignored):
(7)
We now can rewrite equation (6)
1 dl(x) .
(8)
Equation (8) is thus an expression relating the effects of light
scattering and light absorption to the change in spectral light intensity
with distance along a sight path. On the right-hand side of equation (8),
the first term is the. effect
-------
light from the line of sight. This effect would occur if a bright, white
cloud or distant snowbank were observed through an aerosol that did not
contain N02; scattering would cause a yellow-brown coloration. If,
however, I(x) is less than Inrj(x)» tnen tne Quantity in brackets in
equation (8) will be positive, which means that the net effect of scatter-
ing will be to add predominantly blue light into the line of sight. This
effect would occur if a distant, dark mountain were observed through an
aerosol that did not contain N02; scattering would cause the mountain to
appear lighter and bluish. Only light absorption can cause I(X) to be
less than InoU)» and whenever I(X) < Iho(x)» scattering will add light to
the sight path, thereby masking the coloration caused by N02 light absorp-
tion.
The mathematical expressions used in this workbook are simply solu-
tions to equation (1) for different boundary conditions and for different
values of bscat, bext, p(0) and Fs as they are affected by natural and
man-made light scatterers and absorbers. The plume visibility model uses
similar formulations, but it also accounts for multiple scattering
effects.
2.1.4 Plume Visual Impacts
Let us consider now the geometry shown in figure 3, namely, the case
of a plume embedded in an otherwise uniform, background atmosphere.
Equation (1) can be solved for the spectral radiance at the observer
location PQ as follows:
16
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OBSERVER
BACKGROUND
ATMOSPHERE
PLUME
BACKGROUND
ATMOSPHERE
OBJECT
I'D
Figure 3. Object-observer geometry with plume.
17
-------
where
1 - exp (-bfixtrp)
Tn Pplume wplume
exp(-bextrp>
- exp(-bextrq) eXp("Tplume)
obj
'exp(-bextrp)
(9)
M 55
pplume
uplume
spectral radiance at observer point P0,
horizon sky radiance, assuming the atmosphere is
uniform and optically thick (i.e., earth curvature
can be ignored); see equation (4) and figure 2(b),
plume-observer distance; see figure 3,
average plume phase function, corrected for multiple
scattering effects albedo,
average plume albedo
scat
dr
Tp1ume 5
Plume optical thickness (increment above background)
dr
b . )dr
aDS
r E
r s
• / b dr = / (b
plume ext plume scat
distance between viewed object and plume; see
figure 3,
total distance from viewed object and observer; see
figure 3. If the plume is treated as a point, then
ro ' rp + rq
18
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Note that other variables were defined previously and that all the optical
variables (Fs, In, bscat, bext. pp]ljme, fy^. and Tplume) are functions
of wavelength X. Further, note that Ih and p 1ume are dependent on the
scattering angle 0 (see figure 2(a) for a definition). Each term on the
right-hand side of equation (9) has a physical meaning. The first term
represents light scattered into the line of sight by the background atmos-
phere between points ?2 and po- Tne second term represents the light
scattered into the line of sight by the plume material. The third term
represents the light scattered into the line of sight by the background
atmosphere between the object and Pj. The fourth and last term represents
the light reflected from the object and transmitted to the observer.
2.1.5 Characterizing Visibility Impairment
Figure 4 illustrates five situations in which air pollution is
visually perceptible. There are two basic kinds of visibility impacts.
In one case, of which figures 4(b), (c), and (e) are examples, air pollu-
tion is perceptible as a result of the comparison of two objects viewed
simultaneously by an observer. The haze layer and plume in figures 4(b)
and (c), for example, are perceptible because they contrast with the back-
ground atmosphere. The plume in figure 4(e) is perceptible because it
contrasts with the viewed objects; in other words, it is brighter or
darker or colored differently from the viewed object. In the other case,
of which figures 4(a) and (d) are examples, perception of pollution
results from the difference between the presently observed scene and the
scene remembered under clear conditions. For example, the haze in
figure 4(c) may be perceptible because it is colored differently from what
is considered normal sky color; it appears white, gray, yellow, or brown
instead of blue. The situation shown in figure 4(d) is similar. The
scene may appear hazy because the contrast of viewed objects is decreased
from that observed on a clear day.
Each of these situations can be described either by a set of single
contrast values, for different wavelengths or by a set of contrast differ-
ences for different wavelengths; the cases shown in figures 4(a), (b), and
19
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%^^w^
(a) General, uniformly discolored haze
(b) Surface-based haze layer contrasting
with background atmosphere above
(c) Elevated plume or haze layer contrasting
with background atmosphere above and below
Figure 4. Five basic situations in which air pollution
is visually perceptible.
20
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(d) General haze reducing contrast of viewed objects
(e) Elevated plume or ground-based or elevated haze layer
reducing contrast of a portion of a viewed object
Figure 4 (Concluded)
21
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(:) can be characterized by contrast, whereas those shown in figures 4(d)
and (e) can be characterized by contrast differences.
We can use equation (9) to calculate contrast values or contrast dif-
ferences so as to characterize each of the situations shown in figure 4.
First, let us consider the situations in which the effect of air pollution
is perceptible against the sky, as shown in figures 4(a), (b), and (c).
If the atmosphere is relatively hazy, the atmosphere along a horizontal
line of sight is optically thick. In such a situation, for the case with-
out a plume (Tp-|ume = °)» ^ can be snown" tnat equation (9) reduces to
equation (4) [see the asymptote in figure 2{b)].
The contrast between the plume and the horizon sky background as
observed at point P0 is evaluated from equation (9) as follows:
'plume
- h-plume " h
» _
(P ^plume
^background
-1
exp(-bextrp)
(10)
Note that, depending on whether the product of the phase function and
the albedo (pu) for the plume or haze layer is larger or smaller than that
for the background, the plume or haze layer will be brighter (C > 0) or
darker (C < 0) than the background horizon sky. Also note that the con-
trast is dependent on the plume optical thickness (Tplume); as Tplume
approaches zero, Cp-jurne approaches zero. Plume contrast also diminishes
as the plume-observer distance increases.
For the case in which the haze is homogeneous and optically thick, it
can be shown that:
22
-------
chaze '
^""'haze
Jp ^background
(11)
These formulas can be used to evaluate impacts of the type shown in
figures 4(a), (b), and (c). It should be noted, however, that in very
clean areas where background conditions approach Rayleigh conditions, the
assumption that the atmosphere along the horizontal line of sight is
optically thick is no longer valid, and these formulas are only approxima-
tions. In these situations, visibility model calculations are needed for
more accurate solutions.
To characterize the types of visibility impairment represented in
figures 4(d) and (e), we need to calculate a change in sky/terrain con-
trast caused by a plume or haze layer:
where
s cr| - cr|
(with plume (without plume
i / - t-plume " h-plume
- -- 1_ - -
(with plume h-plume
C
r
I without plume h
For simplicity we assume that the terrain that is viewed behind the
plume has an intrinsic radiance, Iobj, which is a function of the horizon
sky radiance Ih, namely, Iobj = (1 + C0)Ih. C0 is the intrinsic con-
trast. If the terrain were black, C0 would equal -1. With this assump-
tion we again use equation (9) to evaluate the following spectral radiance
values:
23
-------
It • !h
* 'h-plume + Vh [•*><-b«tpo>] h><-Tplume>] . <12>
The sky/terrain contrast values with and without the plume are:
= C
without plume
with plume
The change in contrast caused by the plume or haze is then:
exp(-bextro>
-(-M
\ h-plume/
(14)
It should be noted that the visual range and visual range reduction
can be calculated from equations (12), (13), and (14). The visual range
is defined as the distance rv from the observer to a black object such
that the sky/target contrast Cr = -0.02 at X = 0.55 vm. By solving
equations (12), (13), and (14) for r0 * rv such that Cr ' -0.02, we can
obtain the following formulas:
vO
_ 3.912
'ext
for a homogeneous atmosphere without a plume and
(15)
1
}ext
(h-p
3.912- to/JtElfflS-l- r
plume
(16)
24
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The fractional visual range reduction is simply
l^ / h-plume \ +
v vvO \ h / ^ /i7\
= — y-3TT5 • (17)
rvO
Further discussion of the relationships between plume optical thick-
ness, extinction coefficient, visual range, and sky/terrain contrast is
presented in appendix A.
Equations (10) and (14) are the basic formulas upon which this work-
book is based. Because of the assumptions previously noted, these equa-
tions are approximate; more exact solutions can be obtained using the com-
puter-based plume visibility model. Equations (10) through (14) can be
used to determine contrasts at different wavelengths in the visible
spectrum. This workbook describes how calculations can be made at X =
0.40, 0.55, and 0.70 vm. The contrast at X = 0.55 vm is used as an over-
all indication of relative brightness of a plume or haze layer. The con-
trasts at X = 0.40 and 0.70 un are used to determine the coloration of the
plume or haze layer relative to the background. The blue-red ratio,
indicative of coloration, is calculated from these contrast values as
follows:
R .
"
The visibility model uses many parameters to characterize plume
visual impact; however, the following four parameters are particularly
important:
.
> Visual range reduction [see equation (17)]
' 25
-------
> Plume blue-red ratio [see equation (18)]
> Plume contrast [see equation (10)]
> Plume perceptibility parameter AE(L*a*b*).
We have already described the first three parameters. The fourth
parameter, the plume perceptibility AE value, characterizes the extent of
color difference between the plume and a viewing background. Whereas
visual range reduction and plume contrast values are calculated at one
wavelength (X = 0.55 un) and blue-red ratio at two wavelengths (X= 0.4
and 0.7 vm)» the t£ value is calculated across the visible spectrum
(0.4 < X< 0.7 vm). The AE parameter is particularly useful to charac-
terize plume perceptibility because it is a function of the difference in
coloration between the plume and a viewing background in terms of both
brightness difference and color (chromaticity) difference. Because the
spectral radiances [I(X)] have to be calculated at several wavelengths to
determine AE, the AE parameter is not appropriate for use in hand calcula-
tions.
We are not aware of any studies that have specifically addressed the
question of what the standards for visibility impairment should be in
terms of these quantitative specifications. A very well defined, rea-
sonably large target, with sharp edges that contrast with a viewing back-
ground, probably has a threshold of detectability corresponding to a con-
trast of ±0.02 and a AE value of about 1. Figure 4 shows the five basic
viewing situations in which air pollution might be visually perceptible.
A direct comparison of two adjacent colors is only possible when the plume
or haze layer contrasts with a viewing background. In most situations,
however, the boundary between a plume and a viewing background is not
distinct, but diffused, because of the nature of plume dispersion. This
is particularly true at large distances from the emissions source. A
general haze can only be detected by comparison with the memory of clearer
conditions on previous days. Thus, there is no clear set of threshold
values to characterize visibility impairment.
The situation is made even more complicated by the fact that the
26
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magnitude of visual Impact caused 1n a class I area by a given emissions
source varies significantly over the course of a year. Although impacts
may be visible during the worst day in a year, they may not be visible
most of the year. For this workbook, we have adopted the following
criteria for use in level-1 and -2 tests. If the absolute value of either
plume contrast (Cp-j^g) or the change in sky/terrain contrast (ACr) is
greater than 0.1, or if plume AE(L*a*b*) is greater than 4 for the worst-
day impact case, then the possibility that the visual impact would be
judged adverse or significant cannot be ruled out.
2.2 PLUME-OBSERVER GEOMETRY
Figures 5 and 6 show plan and elevation views, respectively, of ah
arbitrary plume-observer geometry defined by elevation angle 6, the hori-
zontal angle a between the line of sight and the plume center!ine, the
distance x downwind from the emissions source of the plume parcel being
observed, and the distance r_ from the observer to this plume parcel.
Although the visibility model offers the option of specifying any
arbitrary angle 3, for most real-world problems 3 2 0 since plumes are
usually not observed at close range. Thus, for the sake of simplicity,
the formulas presented in this workbook are based on the assumption that
the line of sight is horizontal (8* 0).
In the previous section we showed that plume visual effects are
dependent on the plume optical thickness T, which is proportional to the
integrals of N02 and particle concentrations along the line of sight. For
a horizontal line of sight (0=0) through a Gaussian plume, these
integrals can be calculated using the following approximate formulas.
For a fixed plume orientation and observer location, as shown in
figure 5, the magnitude of plume optical thickness (T) in equations (10)
ard (14) is a function of the direction of view (i.e., the angle a).
Although the optical thickness T of the plume is a minimum at a * 90", the
plume-observer distance rD is at its minimum value also since
" >
27
-------
LINE OF SIGHT
DEMISSIONS
SOURCE
^OBSERVER
Figure 5. Plan view of observer-plume geometry.
28
-------
OBSERVER
PLUME
CROSS-SECTION
GROUND
Figure 6. Elevation view of observer-plume geometry
29
-------
- p-nnn
rpo ~ sin a
Thus, there are two counterbalancing effects of a. Although the
optical thickness of the plume is larger for small as, the distance
between the plume and the observer is larger, the magnitude of plume
effects is correspondingly smaller, and the apparent size of the plume is
smaller. In very clear background areas, if the observer is close to the
source, impact magnitudes will be largest for lines of sight with small
as, though the plume will appear smaller as noted above. However, in most
situations visual effects are maximum or close to maximum when the line of
sight is perpendicular to the plume (a = 90°) such that r_ = rp_m1-n
Because of this, we recommend, for this workbook, that plume effect:
evaluated for lines of sight perpendicular to the plume centerline.
The optical thickness of a plume is proportional to
x dy =
(2ir) ' o u sin a
exp
exp
(19)
For lines of sight directly through the center of a Gaussian plume,
we have simply
xdy =
(2*r/2Vu sin a
(20)
When the plume is uniformly mixed in the vertical between the ground
and an elevated stable layer of height, H,,,, we have
30
-------
Note that these formulas no longer apply as a approaches 0. If the
observer were within the plume, the integral along the plume centerline (a
= 0*) would have to be calculated numerically from the Gaussian
equation. As we discuss in a later subsection of this section, the proba-
bility of an observer's being within the plume is exceedingly small, so
that a quite adequate general description of plume-observer geometry is as
shown in figure 5 (i.e., lines of sight oblique to the plume centerline).
It should be understood from the foregoing discussion that visual
impacts are a function of the following parameters:
> N02 and aerosol plume loading (Q)
> Wind speed (u)
> Vertical extent of plume mixing (az or H^)
> Distance between the plume and observer (rp)
> Background extinction coefficient (bext).
Thus, the visual impacts will increase with:
> Increasing NOX, particulate, and aerosol precursor emis-
sion rates.
> Increasing NC^ and aerosol formation rates in the atmos-
phere from precursors.
> Decreasing wind speed.
> Decreasing vertical mixing.
> Decreasing plume-observer distance (i.e., the wind direc-
tion is such that plume transport is toward the observer).
> Increasing background visual range (i.e., decreasing
•extinction coefficient, the lower bound being the Rayleigh
scattering coefficient of particle-free air).
31
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The largest visual impacts for a given emissions source and observer
location (in a class I area) occur when a plume is transported relatively
close to the observer, with light winds and little vertical mixing. Thus,
to estimate worst-case impacts, it is necessary to identify reasonable
worst-case meteorological conditions such as light-wind, stable condi-
tions; light-wind, limited-mixing conditions; and stagnation conditions.
These worst-case conditions are dependent on meteorological conditions in
the area and the distance between the emissions source and the class I
area. For example, although an F stability and a 1 m/s wind speed may be
reasonable worst-case conditions for visual impacts close to a source,
they certainly are not for observer locations 100 to 200 km from the
source. At 1 m/s, it would require 28 to 56 hours for a plume to be
transported 100 to 200 km. Typically, stable (F stability) conditions
would not be likely to persist for more than 12 hours.* If we assume that
a stable plume would remain intact for no longer than 12 hours, the worst-
case wind speeds for the observer locations 100 and 200 km from the emis-
sions source would be 2.3 and 4.6 m/s, respectively. In this workbook we
use this assumption regarding persistence of stable conditions.
Another consideration is that of variability in wind speed and wind
direction, and of its impact on plume dispersion and transport to within
view of an observer in a class I area. The location of a plume parcel
relative to the emissions source at any time tf is dependent on the
spatially- and temporally-varying windfield, the time of emission from the
source t0, and the transport time & = tf - tQ:
ff
r - I v(x,y,z,t) dt
(22)
It should be noted that, during winter or at high latitudes, stable
conditions (E or F stability) could persist longer than 12 hours. The
analyst may wish to use a different assumption regarding persistence if
appropriate to a given application.
32
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If the displacement vector r is within a given radius of the observer
point in a class I area, one might expect a visual impact, depending on
the dilution of the plume parcel. Thus, we could have transport from the
emissions source to the observer locations in any number of possible
trajectories, as shown by the examples in figure 7. If one had a set of
spatially- and temporally-resolved wind data, one could perform the vector
integration shown in equation (22) and determine the frequency of occur-
rence of transport toward a class I area. Usually, however, wind data are
not available for more than one location in a region, and one must make
assumptions regarding the variability of wind in time and space.
Uncertainty in the meteorological conditions used for input is
probably the most important source of error in visibility impact calcula-
tions. The level of sophistication of an air quality or visibility impact
analysis is most often limited, not by theoretical or analytic concerns,
but by the lack of a detailed meteorological data base for the region of
interest, with spatial and temporal resolution appropriate for the task.
The level-1 visibility screening analysis is based on assumptions
regarding worst-case meteorological conditions. The level-2 visibility
screening analysis is based on the assumption that the joint frequency of
occurrence of meteorological conditions, at plume height, at a point
within a region, is representative of all points within the region. It is
also assumed that plume geometry can be approximated by a straight plume
trajectory, as shown by trajectory 1 in figure 7. This assumption will be
conservative in most situations (i.e., overestimate impacts). However, in
other situations, such as during a stagnation condition in a valley, the
assumption may cause underestimation of impacts because wind reversals
could cause a buildup of emissions as shown by trajectory 2 in figure 7-
For level-3 analyses more detailed representations of the windfield could
be used as the basis for visibility impact calculations, depending on the
availability of meteorological data.v
33
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2.3 CHARACTERIZING THE FREQUENCY DISTRIBUTION OF PLUME VISIBILITY
IMPACTS
In this workbook, the purpose of level-1 and -2 screening analyses is
to estimate the worst-case visual impacts that might occur on about one
day per year. For the 1evel-3 analysis, the frequency of occurrence of
impact of different magnitudes can be calculated, as well as the worst-day
impacts. It is important to determine the frequency of occurrence of
visual impact, because the adversity or significance of impact is
dependent on how frequently an impact of a given magnitude occurs. For
example, if a plume is perceptible from a class I area a third of the
time, the impact would be considered much more significant than if it were
perceptible only one day per year. The assessment of frequency of occur-
rence of impact should be an integral part of a visibility impact assess-
ment.
In this subsection we discuss how one can determine both the magni-
tude and frequency of occurrence of visual impact. This procedure entails
making several model runs for different values of the following important
input parameters:
> Emission rates (particulate, S02, NOX).
> Wind speed.
> Wind direction.
> Atmospheric stability.
> Mixing depth.
> Background ozone concentration.
> Background visual range.
> Time of day and season.
> Orientation of observer, plume, and sun.
> Viewing background (whether it is sky, cloud, or snow-
c'overed, sunlit, or shaded terrain).
Because df the large number of variables important to a visual impact
35
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calculation, several calculations are needed to assess the magnitude and
frequency of occurrence of visual impact. It is recommended that a
computer model be used for level-3 analysis because of the large number of
scenarios and calculations involved. It would be ideal to calculate
hourly impacts over the course of a year or more using hourly values of
the above variables. However, such an extensive data base is rarely
available for use. Even if it were available, the computing costs
involved would be prohibitive. It is therefore preferable to select a few
representative, discrete values for each of these variables to represent
the range (i.e., the magnitude and frequency of occurrence) of visual
impact over a given period of time, such as a season or year. One can
start with conditions that cause the worst impacts and then assess the
frequency of occurrence, in a season or year, of all the variables having
worst-case values simultaneously.
It is possible to imagine a worstrcase impact condition that would
never occur in the real atmosphere; this condition could be represented on
a cumulative frequency plot, such as that of figure 8, as point A. The
impact is great, but it almost never occurs. If another worst-case situa-
tion less extreme than point A were selected, the magnitude of impact
would be less, but it might occur with some nonzero frequency, about one
day per year, for example (the reasonable worst-case impacts for level-1
and level-2 analyses). It is possible to select various values of all the
important input variables and to assess the frequency with which those
conditions resulting in impacts worse than a given impact would occur. By
this proress, several points necessary to specify the frequency distribu-
tion could be obtained (for example, points B, C, and D in figure 8).
With average (50-percentile) conditions, a negligible impact, as shown at
point E in figure 8, might be found. In figure 8, the ordinate could be
any of the parameters used to characterize visibility impairment, such as
visual range reduction, plume contrast, blue-red ratio, or /£, and the
abscissa could represent cumulative frequency over a season or a year.
In 4 visual impact assessment, it is recommended that one select
various combinations of upper-air wind speed, wind direction, and atmos-
36
-------
i.
OJ
4-3
to
re
CL-
"
as
25 50 75
Cumulative Frequency of Occurrence (%)
100
Figure 8. Example of a frequency distribution of visual impact.
37
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pheric stability; background ozone concentration; and background visual
range to specify the frequency distribution of visual impact. If one has
a large, concurrent data base of all five of these variables, it would be
desirable to calculate a five-way joint-probability distribution matrix
and to use these joint probabilities to calculate frequency of occurrence
of impact. However, in most situations, such a data base is not
available, and one must treat the various worst-case events as independent
probabilities. With this assumption, the probability of worst-case
impacts can be calculated by multiplying the independent probabilities.
This can be represented as follows:
f(y > y') = n f(x. > x^)
where f(y > y1) is the cumulative frequency of impact y greater than y1,
and f(x^ > x^1) is the cumulative frequency of variable x-j having values
that would cause greater impact than the value x^'.
In such an application, one might obtain an estimate of cumulative
frequency by using the joint frequency distribution of upper-air wind
speed and wind direction and the separate frequency distributions of
upper-air stability, ozone concentration, and visual range. For example,
the plume perceptibility parameter AE has a cumulative frequency distribu-
tion that can be estimated as follows:
f(AE > AE1) = f(u < u', WD < WD1) • f(s > s1)
where
f([03] > [03]') • f(ry > ry')
f(AE > AE') = the frequency of occurrence of AE values
greater than AE'. AE1 is calculated on
the basis of a wind speed u1, wind direc-
tion WD1, stability s1, ozone concentra-
tion [03]', and visual range rv'.
f(u < u1, WD < WD1) = the frequency of occurrence of wind speeds
38
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less than u1 associated within a specified
value (WD1) of the worst-case wind direc-
tion.
f(s > s1) « the frequency of occurrence of stabilities
greater than s1.
> [03]') = the frequency of occurrence of background
ozone concentrations greater than [03]'.
f(ry > rv') = the frequency of occurrence of background
visual range values greater than rv'.
Each of the input parameters that are important to the visibility model
calculation varies significantly over the period of a year, and all are
discussed in the following paragraphs.
2.3.1 Wind Speed
Wind speed affects plume visual impact strongly because plume center-
line concentrations and plume line-of-sight integrals are inversely pro-
portional to wind speed. Greater impact would be expected during light-
wind stagnation conditions than during strong-wind, we11-ventilated condi-
tions. Also, since the age of a plume parcel at a given distance downwind
from a power plant is inversely proportional to wind speed, more time is
available at low wind speeds for the chemical conversion of primary emis-
sions. A well-aged plume parcel is more likely to cause a reduction in
visual range than is a younger one. However, the time necessary to trans-
port emissions a given distance toward a class I area increases with
decreasing wind speed. Thus, during light-wind conditions, several hours
of persistent conditions may be needed to transport emissions to a class I
area where they could cause visual impact.
2.3.2 Wind Direction
Wind direction also affects plume visual impact, because the direc-
tion of plume parcel transport affects the orientation of the plume with
respect to the'observer. If the plume is transported directly toward an
39
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observer, the observer's line of sight directly along the center of the
plume is significantly affected. As noted previously, if the observer's
line of sight is oblique to or along the plume axis, plume optical thick-
ness will be greater than if the line of sight is normal to the plume
axis. However, there is a compensating effect; the direction of plume
transport affects the distance (rp) between the observer and the plume
material. Plume discoloration is.diminished by light scattered by the
intervening, or background, atmosphere. The more distant the plume
material, the less colored and less perceptible it is likely to be. This
decrease in plume coloration can be expressed as follows:
3-9 VvO> • <23>
where
Cplume(r)» Slume(O) = plume contrasts at plume-observer
distances r and 0, respectively.
rp = plume-observer distance.
ryQ = background visual range.
It should be noted that visual range reduction does not decrease with
increasing distance between the plume and the observer, assuming one can
still see across the plume. However, the aesthetic effects of this visual
range reduction would be less, since contrast reduction (ACr) would
decrease exponentially, as the plume-object distance increases as shown in
equation (14). Also, it should be noted that with a more distant plume,
only the contrast of distant terrain objects would be affected and fewer
lines of sight would be impacted. In addition, the aesthetic impact
caused by plume discoloration is likely to be less if the plume is farther
away, because the plume will appear smaller (i.e., fewer lines of sight
will be affected).
To illustrate the effect of wind direction, figure 9(a and b) shows
the positions of two plumes from a hypothetical emissions source relative
to a vista in a class I area 90 km away. Plume ±2 0y outlines are shown
40
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EMISSIONS SOURCE
POTENTIALLY IMPACTED
LINES OF SIGHT
VISTA IN A CLASS I AREA
Von
(a) Worst-Case Wind Direction
Figure 9. Schematic diagram showing plume-observer geometry
for two wind directions.
41
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EMISSIONS SOURCE
POTENTIALLY IMPACTED
LINES OF SIGHT
VISTA IN A CLASS I AREA
(b) Wind direction resulting in less impact than the worst case,
Figure 9 (Concluded)
42
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to scale with oy values appropriate for a Pasquill E stability. Of
course, actual plume trajectories would be affected by wind channeling,
complex terrain, and changes 1n wind direction with time, so these figures
are only idealized representations. Figure 9 shows trajectories that
could occur with north-northwesterly and north-northeasterly winds. A
plume associated with a north-northeasterly wind direction (defined by a
sector 22.5* wide) could be anywhere within the extremes of the sector
shown in figure 9. Thus, a wide range of impacts could occur associated
with north-northeasterly winds. The worst case would be that shown in
figure 9(a), in which the plume is transported directly toward the obser-
ver. Of course, the worst-case conditions of figure 9(a) would occur for
only some of the periods of north-northeasterly flow. Figure 9(b) shows
that, for another wind direction, plume discoloration would be consider-
ably less, because plumes would be tens of kilometers away from the
observer, and the observer's line of sight could be nearly perpendicular
to the plume, not along the plume as in figure 9(a). Since the case shown
in figure 9(a) is not a likely occurrence, the level-1 and level-2
analyses are not suitable for evaluating the visual impact associated with
this plume-observer orientation. A level-3 analysis is required when
views along the plume axis are of concern.
2.3.3 Atmospheric Stability
Upper-air stability controls the rate at which source emissions are
mixed with ambient air. During stable conditions, diffusion is limited,
particularly in the vertical direction, so plumes remain as ribbon-like
layers. Plume discoloration is most apparent during such stable condi-
tions, because the integral of N02 and participate concentrations along
the line of sight is greater. During well-mixed (neutral or unstable)
conditions, plumes are rapidly diffused and not likely to be visible as
plumes per se.
Stability, or the rate of plume mixing, also has an effect on
chemical conversion within a plume. The conversion of nitric oxide (NO)
to nitrogen dioxide (N02) is diffusion-limited in stable plumes, as is the
43
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formation of sulfate and nitrate, because background ozone that effects
N02 formation is depleted within the plume.
2.3.4 Background Ozone Concentration
An important input parameter to the visibility model is the back-
ground ozone concentration, that is, the concentration of ozone outside
the plume. Ozone reacts directly with the colorless nitric oxide emitted
from power plants to form the brownish gas, nitrogen dioxide, the princi-
pal plume colorant:
NO + 03 * N02 + 02
Ozone is also indirectly important in the oxidation of plume N02 and S02,
since ultraviolet radiation photolyzes ozone to form the hydroxyl radical
(OH-) that reacts with N02 and S02 to form nitric acid and sulfate aero-
sol.
Calculations should be made for the median (50-percentile) background
ozone concentration as a minimum and possibly for the 25- and 75-
percentiles also.
2.3.5 Background Visual Range
Background visual range is also an important input parameter, because
the magnitude of plume discoloration visible from a given location depends
on the clarity of the intervening atmosphere. Plume discoloration is much
more noticeable in the extremely clear areas of the Southwest, for
example, than in hazy areas. Equation (23) shows that as the background
visual range (r Q) decreases (i.e., the atmosphere becomes hazier), the
degree of plume discoloration decreases also. Thus, one must supply one
or more (e.g., 25-, 50-, and 75-percentile) values of background visual
range in the study area to characterize impacts for different levels of
atmospheric clarity.
44
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2.3.6 Study Area Topography
The topography of an area also has an influence on visibility impair-
ment. High terrain affects the transport of emissions, particularly dur-
ing worst-case stable conditions. It is likely that a stable plume would
be channeled by high terrain and remain in a valley. Thus, the assumption
of a straight plume trajectory approaching an observer location on ele-
vated terrain, such as is shown in figure 9(a), may never occur in some
areas. The topography also affects the rate of dilution of plumes, with
mechanically induced turbulence enhancing plume dilution.
Topography also affects the views from a given vista location. For
example, topography can obstruct views in certain directions from a vista
where plume material is located. It can also have an effect on the type
of viewing background (what is visible behind the plume), which has an
effect on plume discoloration.
2.3.7 Season and Time of Day
Gas-to-particle conversion is also a function of season and time of
day, with higher conversion rates at times when ultraviolet flux is great-
est. Also, the sun angles (i.e., azimuth, zenith, and scattering angles)
are dependent on season and time of day.
2.3.8 Model Runs
If one used all the permutations of the important input variables,
one could make hundreds of plume visibility model runs to characterize the
frequency distribution of visual impact over a season or a year. For
example, if 5 wind directions, 3 wind speeds, 2 stabilities, 3 background
visual ranges, 3 background ozone concentrations, and 2 seasons are evalu-
ated, one would have to make 540 runs (5x3x2x3x3x2). Further-
more, if 10 downwind distances were evaluated and 4 viewing background
colorations were considered for each line-of-sight geometry, a total of
21,600 individual line-of-sight calculations would be needed. The comput-
45
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ing costs for this many calculations would be prohibitive. To reduce
costs, one can reasonably approximate the frequency distribution of
impacts by using median values of background ozone concentrations and
visual range and evaluating impacts for sun angles corresponding to one
season (e.g., spring or fall), thus reducing the total number of runs in
this example to 30.
46
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3 LEVEL-1 VISIBILITY SCREENING ANALYSIS
The level-1 visibility screening analysis is a simple, straightfor-
ward calculation designed to identify those emissions sources that have
little potential of adversely affecting visibility in a class I area. If
a source passes this first screening test, it would not be likely to cause
adverse visibility impairment, and further analysis of potential visi-
bility impacts would be unnecessary. If the source fails this test, addi-
tional screening analysis would be needed to assess potential impacts.
The level-1 visibility screening analysis requires a minimal amount
of information about the source and only a few minutes of an analyst's
time to evaluate potential visibility impairment. The Input parameters
needed to evaluate potential visibility Impacts with this screening analy-
sis procedure are as follows:
> Minimum distance of the emissions source from a poten-
tially affected class I area (in kilometers).
> Location of the emissions source and class I area.
> Partlculate emission rate (in metric tons/day).
> NOX emission rate (in metric tons/day).
> S02 emission rate (in metric tons/day).
3.1 DERIVATION OF LEVEL-1 SCREENING ANALYSIS
The level-1 visibility screening analysis is designed to evaluate two
potential types of visibility impairment that can be caused by plumes from
emissions sources. These two types of visibility Impairment are caused by
nitrogen oxide, partlculate, and sulfur dioxide emissions. Figures 10 and
11 illustrate the two types of plume impacts. One 1s a discolored, dark
47
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HORIZON SKY
VIEWING BACKGROUND
TERRAIN VIEWING'
BACKGROUND
Figure 10. Two types of plume visibility impairment considered in the
level-1 visibility screening analysis.
BLACK TARGET OR-
HORIZON SKY VIEW-
ING BACKGROUND
EMISSIONS SOURCE
OBSERVER'S LINE OF SIGHT-
(PERPENDICULAR TO PLUME
CENTERLINE) AT DOWNWIND
DISTANCE X
OBSERVER
Figure 11. Geometry of plume, observer, and line of sight used in
level-1 visibility screening analysis.
48
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plume observed against a bright horizon sky (labeled 1 in figure 10).
This effect is caused principally by N02 gas formed from NOX emissions,
though particulates can contribute in some cases. The other type is a
bright plume observed against a dark terrain viewing background (labeled 2
in figure 10). Tlrs effect is caused principally by particle emissions
and sulfate aerosol formed from S02 emissions.
Model calculations (Latimer et al., 1980a) suggest that sulfate
aerosol does not form in stable plumes containing a significant amount of
NOX. Sulfate formation does not occur until emissions are diluted sig-
nificantly with background air. However, the visual impacts caused by NOX
and particulate emissions are greatest when the plume material is concen-
trated, as in light-wind, stable conditions. For these reasons, we con-
sider two different meteorological conditions:
> For maximum impact caused by particulate and NOX emis-
sions: stable (Pasquill-Gifford stability category F),
light-wind conditions with a 12-hour transport time to the
closest class I area.
> For maximum impact caused by S02 emissions: limited
mixing conditions, vertically well-mixed plume within a
1000 m mixing depth, 2 m/s wind speed.
For both cases, the geometry of the plume, observer, and line of
sight assumed for this screening analysis is shown in figure 11. The
plume is assumed to pass very close to the observer, with its centerline
half the width of a 22.5* sector away from the observer at the given down-
wind distance x. The observer's line of sight is assumed to be perpen-
dicular to the plume centerline. The viewing background is assumed to be
either the horizon sky or a black terrain object located on the opposite
side of the plume a distance equivalent to a full sector from the
observer.
49
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3.1.1 Impacts of Participate and NOX Emissions
Meteorological conditions are assumed to be stable with light
winds. Pasquill-Gifford F stability is used to characterize the vertical
dispersion (oz) important in evaluating the visual impacts for horizontal
lines of sight. Since such stable conditions are not likely to persist
for more than 12 hours in a typical diurnal cycle, we selected a worst-
case wind speed that would transport emissions from the source to a
class I area in 12 hours. Thus, wind speed is determined as a function of
distance x to the class I area as shown below:
(x km)(1000 m/km) _ „ ,. 1n-2, x ,
o Uv.\rocrtrt cpr/hr) t»JA iu v*/ "i/a
Thus, a 2.3 m/s wind would be used to evaluate impacts in a class I area
100 km from the emissions source.
The horizontal optical thickness through the center of an elevated
stable plume is
T =
(2ir)r72ozu
where Q is the mass emission rate of NOX and particles multiplied by the
respective light absorption and scattering efficiencies of these two
species. For the level-1 analysis we conservatively assume that there is
complete conversion of NOX emissions to N02 in the atmosphere.
We can calculate the absorption (N02) and scattering (particle) com-
ponents of the plume optical thickness separately, as follows:
50
-------
p QN02 '
Vt* "scat"""'1"3) ""part •
where
1
P
The value of p 1s evaluated so that the units of Qpart and QNQ in
the above formulas are in metric tons per day:
p = (1012 uq/metric ton)(dav/24 hrHhr/3600 sec)
. 2.0 • 108
The absorption per unit mass of N02 is calculated for a wavelength of
0.55 un as follows [Dixon, 1940):
O31
(1881 yg/m3/ppm)(1000 m/km)
The scattering coefficient per unit mass of aerosol for a wavelength
of 0.55 un was calculated using Mie scattering theory. A primary particle
size distribution typical of a coal-fired power plant equipped with an
electrostatic precipitator (Schulz, Engdahl, and Frankenberg, 1975) was
assumed. This distribution has a mass median diameter of 2 un, a geomet-
ric standard deviation of 2, and a density of 2.5 g/cm3. For such a size
distribution:
51
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bscat/(ug/m3) = 10
We can use equation (10) from chapter 2 to evaluate the sky/plume
contrast resulting from N02 light absorption. For this level-1 analysis,
we assume that the phase functions for the plume and the background atmos-
phere are equal. With this assumption, equation (10) reduces to the
following equation:
TNO,
'Plume Tpart + TNO,
- exp -T
part
exp
('
3.912 rp/ry()
where
rvO
TN02» Tpart
rp = the observer-plume distance, which, for the
geometry shown in figure 11,
= x tan I22i5 [ = 0.199 x ,
= background visual range (km),
= NOg and particulate components of plume optical
thickness, as discussed above.
It should be noted that this equation can be simplified (valid only
for small plume optical thicknesses, T < 0.1) by using the first two terms
of a series expansion of the second term:
NQ exp(-3.912
From this approximate formula we see that the sky/plume contrast is
proportional to the plume N02 line-of-sight Integral (T$Q) and decreases
as the plume-observer distance increases.
52
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Now let us consider the reduction in sky/terrain contrast by the sane
plume". If the background terrain is black, then C0 * -1, and we can
rewrite equation (14) as follows:
exp(-3.912 r0/rv0)
where Cplume is as defined above, and r0 is the observer-object distance,
which, for the geometry shown in figure 11, equals 2 • x • tan (22.5 /2),
where x is the downwind distance from the emissions source to the class I
area.
3.1.2 Impacts of S02 Emissions
We evaluate the worst-case impacts of S02 emissions, assuming a mul-
tiday stagnation episode (limited mixing). Both primary particle emis-
sions and sulfate ($04*) aerosol formed in the atmosphere from S02 emis-
sions reduce the contrast of objects viewed through the plume. However,
NOX emissions are converted to nitric acid vapor by reaction with the
hydroxyl radical, the same species responsible for conversion of S02 to
S04=. Hence, no N02 is assumed to be present.
Since sulfate forms slowly in the atmosphere, the maximum impact does
not necessarily occur at the class I area closest to the emissions
source. Thus, for the level-1 analysis we evaluate sulfate impacts at a
distance of 350 km from the source, the equivalent of two days' transport
time from the emissions source for an assumed 2 m/s wind speed. Further-
more, we evaluate the sky/terrain contrast reduction of a terrain feature
located one-fourth the background visual range distance. The contrast
reduction of a terrain feature at this distance is a maximum for a given
increase-in extinction coefficient (see appendix A). Note that the plume
itself would not be visible, but plume material uniformly diffused through
the mixed layer could cause a reduction in sky/terrain contrast.
53
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The sulfate mass flux at any given distance downwind is calculated by
solving the following differential equations:
d«so.
-TT • -("f * *d)QSo2 •
dt = 1%5 kf
where
QS04= 2 mass flux of S02 and SO^, respectively, in the
plume at downwind distance corresponding to
transit time t,
kd = rate of S02 loss due to surface deposition
kf = rate of S02-to-S04~ conversion
vd = deposition velocity ,
Hm = mixing depth.
The solution to these equations is
V = w*k> S 1 " exp[('kf
For an assumed transit time of 48 hours, mixing depth ^ of 1000 m,
S02 deposition velocity (diurnal average) vd of 0.5 cm/s, and S02-to-S04S
conversion rate (diurnal average) kf of 0.5 percent/hr, we find that the
sulfate mass flux is:
* = °-218 Qso2
54
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We assume an average scattering coefficient per unit mass concentra
tion of sulfate and primary particles of 6 x 10"6 and 1 x lO^m'Vdfl/
respectively, appropriate for typical size distributions (see Latimer et
al.t 1978, and Schulz, Engdahl, and Frankenberg, 1975). The optical
thickness due to total aerosol for this limited mixing case is then
simply:
Taerosol
_ (Opart* !-31
u
Now if we substitute the appropriate values of u and Hm, and the
appropriate conversion factor from metric tons per day to wg/s, we have
the following expression:
•
Taerosol s <5-79 ' 10~3) (Opart * X'31 QS02>
This is the total optical depth across a plume at a downwind distance
of 350 km (transit time » 48 hr). We wish to use the optical depth
between the observer and a terrain feature at the most sensitive distance,
ro a rVQ/3.912, as shown in appendix A. Thus, we must correct Taerosoi
accordingly. We assume the plume is uniformly mixed within a 22.5*
sector, which is quite wide 350 km downwind:
2(x)tan l^rM • 2(350 km)(0.199) = 139 km
The ratio of the optical depth between the observer and the most sen-
sitive terrain feature to the total optical depth is then
rvO
545 km
55
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Thus, we end up with the following expression:
Wosol • I1'06 x 10~5>(rvO> ("part + ^ "so,) •
where rvg is the background visual range in km, and Qpart and Qso are
particle and $62 emission rates in metric tons per day.
Substituting this optical thickness into equation (14) and assuming
that Cplume = 0, we have the following expression for the contrast reduc-
tion caused by sulfate aerosol and particulate emissions during a stagna-
tion episode:
*r-0.368[l -exp(-raerosol)] .
3.2 INSTRUCTIONS FOR LEVEL-1 SCREENING ANALYSIS
The level-1 screening procedure comprises these steps:
- *
> Determine the minimum, straight-line distance x, in kilo-
meters, between the emissions source and the closest
boundary of a class I area. Determine oz corresponding to
this distance for Pasquill-Gifford F stability from figure
12 (Turner, 1969). If x > 100 km, set oz - 100 m. Compute
the plume dispersion parameter p as follows:
,
-------
0.1
0.2
0.5
2345 10
Distance Downwind (km)
15 20 30 4050
100
Source: Turner C1969).
Figure 12. Vertical dispersion coefficient (oz) as a function
of downwind distance from the source
57
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where az is in meters and x is in kilometers.
> From the total mass emission rates of participates (Qpart)
and nitrogen oxides as NC^ (Q^o ) in metric tons per day,
calculate the following optical thicknesses:
10 * 10"7 p • (p-2)
X1 " 1>7 "10" p QN°, • (p-3)
u X
Determine locations of the emissions source and the
class I area on the map shown in figure 13 and the appro-
priate value, rVQ, of the background visual range in kilo-
meters. If the emissions source and class I area are in
different visibility regions, use the larger value of rVQ
in subsequent calculations.
Calculate the following optical thickness parameter for
primary and secondary aerosol:
'aerosol ' »•<* * 10'5>(w + IM QS02)' (P~4'
Calculate the following contrast parameters (note that Cj
is plume contrast against the sky, fy is Plume contrast
against terrain, and C3 is a change in sky/terrain
contrast caused by primary and secondary aerosol):
* The values of rVQ shown in figure 13 are estimated mean visual ranges in
kilometers at 0.55 un based on the work of Trijonis and Shapland
(1979). Their values, based on human observation of terrain features
at National Weather Service meteorological stations, have been Increased
by 50 percent to agree with mean visual range measurements made in
the Southwest (Malm et al., 1979) using a telephotometer equipped with a
narrow band filter at 0.55 un. This correction was made because it is
believed that the telephotometer provides more accurate measurements of
visual range than those produced by human observation.
58
-------
O1
Figure 13. Regional background visual range values (rvo) for use in level-1
visibility screening analysis procedure.
-------
Co =
1 -
-T
part
exp(-1.56 x/ry0)
(P-5)
(P-6)
0.368
(P-7)
> If the absolute value of C^, C2, or C3 is greater than
0.10, the emissions source fails the level-1 visibility
screening test, and further screening analysis is required
to assess potential visibility impairment. If the abso-
lute values of Cj, C2» and 63 are all less than 0.10, it
is highly unlikely that the emissions source would cause
adverse visibility impairment in class I areas; therefore,
further analysis of potential visibility impacts would be
unnecessary.*
This screening procedure could be used as an aid in siting studies. The
distance xmin could be determined so that the criteria for Cj and C^
would be met on the basis of a given regional background visual range
and NOX and particulate emissions rates. The industrial planner could
use this X^Q distance as a factor in his siting analysis. If the
preferred site were at a distance x < xmin from a class I area, further
analysis (level-2 and possibly level-3) of potential visibility impacts
would be needed to evaluate the acceptability of the site.
60
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3.3 EXAMPLE APPLICATIONS OF THE LEVEL-! ANALYSIS
3.3.1 Example 1
Suppose we evaluate a hypothetical, large power plant located 100 km
from a class I area in southern Utah. The power plant emits 10 metric
'tons/per day of particulates, 100 metric tons per day of NOX (as N02), and
200 metric tons per day of S02-
For x - 100 km, the Pasquill-Gifford stability class F, oz = 90 m.
Thus, we calculate the following values:
lo4
Tpart ° (1° x 10~H2-22 x 10)(10) " 0-222
TNQ « (1.7 x 10"7)(2.22 x 104)(100) « 0.378
From figure 13 we see that the background visual range for southern
Utah is 170 km.
We calculate the following parameters:
Taerosol * (1'06 * 10~5)(170)(10 + 1.31 • 200) = 0.490
Cl * " 0 222 + 0 378 ^ " exp("°'222 " 0.378)][exp(-0.78 • 100/170)]
- -0.180
61
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exp(-0.222 - 0.378)
)1
I
exp(-1.56 - 100/170)
= 0.132
C3 = 0.368 [1 - exp(-0.490)] = 0.143
Since the absolute value of each of these contrast parameters (Cj,
C£, and 03) is greater than 0.10, we cannot rule out the possibility that
this hypothetical power plant would cause adverse or significant visi-
bility impairment in the class I area. This is not to say that the source
actually does cause such impact. It means only that it does not pass the
level-1 screening test. Further level-2 or level-3 analysis may show that
the visual impact is not significant or adverse.
The reader can verify that if this power plant were sited at least
150 km from a class I area in the same region, it would pass the first two
tests (i.e., ICjl < 0.10 and |C2I < 0.10); however, it would still fail
the third level-1 test (C3 = 0.143 > 0.10). The reader can also show that
if the same plant were sited in a region with 40 km visual range at the
same distance (100 km), it would easily pass the level-1 screening
tests. Indeed, in such a region the source could be located as close as
70 km and still pass the level-1 tests.
Let us return to our original example and consider whether the source
could meet the level-1 tests by cutting particulate and S02 emissions in
half. By doing this, the reader can verify that, though C2 is reduced
from 0.132 to 0.097, and C3 is reduced from 0.143 to 0.080, ICjl actually
is increased from 0.180 to 0.189. Thus, even with particulate and S02
controls, the source would not meet the level-1 Cj test. In order to do
so, NOX emissions would have to be reduced or the plant would have to be
sited about 150 km away from the class I area.
62
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It is interesting to note that IC^I is best reduced by NOX emissions
control, |C2I is best reduced by participate emissions control, and 103!
is best reduced by SOg emissions control. Only |Cj| and IC^I can De
reduced by increasing the distance between the site and the class I area.
3.3.2 Example 2
-Consider the impact of a proposed plant that would emit 20 metric
tons per day of particulate matter and no NOX or SOg, and would be sited
50 km from a class I area in southern Arizona. We calculate the following
parameters:
Tpart s (1° ' 10~7H5-13 ' 104)(20) * 1.03
We see from the map shown in figure 13 that the background visual
range (rvg) in southern Arizona is 110 km.
Taerosol * (1'06 ' 1°~)(UO)(20 + 1.31 • 0)
2.33 • 10"2
Now we calculate the contrast parameters:
" i 03 + o Cl " exP<-1-03 ' 0)][exp(-0.78 • 50/110)] « 0
63
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- 0)1
exp(-1.03 - 0) [exp( -1.56 • 50/110)] = 0.316
C3 = 0.368 [1 - exp(-0.0233)] = 0.008
Since ^2 is greater than 0.10, there is a potential for visibility
impairment in the class I area, and further screening analysis (level-2 or
level-3) would be needed. However, if participate emissions were cut to
four metric tons per day or less, the source would pass the level-1
screening test, and further analysis would be unnecessary.
64
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4 LEVEL-2 VISIBILITY SCREENING ANALYSIS
A level-2 visibility screening analysis should be carried out when a
level-1 screening analysis shows a potential for adverse or significant
impairment. The level-2 analysis is based on more detailed information
regarding the emissions source, regional meteorology, and other physical
specifications of the site such as background visual range, ozone concen-
tration, and topography. The primary objective of this level-2 analysis
is to calculate the magnitude of visual impact that would be exceeded
approximately one day per year. If the magnitude of this reasonable
worst-case condition is less than some threshold value, one could be
assured that an adverse or significant impact would not occur and further
assessment would be unnecessary.
4.1 IDENTIFICATION OF WORST-CASE CONDITIONS
The following factors should be considered when identifying the
reasonable worst-case conditions for a level-2 visibility screening
analysis:
> Locations of emissions source and class I area(s)
> Wind speed
> Wind direction
> Atmospheric stability and mixing depth
> Time of day and season
> Background ozone concentration
> Background visual range
> Persistence of meteorological conditions
> Topographical effects on plume transport and diffusion.
65
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Many of these factors have to be considered in any event when analyz-
ing air quality impacts from a proposed emissions source in order to
determine whether the source complies with ambient air quality standards
and PSD increments. However, visibility impact assessments differ from
air quality impact analyses in one important respect: air quality impact
analyses are concerned with time-averaged, ground-level contaminant con-
centrations, whereas visibility analyses are concerned with instantaneous
N02 and particle line-of-sight integrals, not necessarily at ground level.
In the following paragraphs we discuss each of these factors and the
manner in which overall worst-case conditions should be selected for
level-2 visibility screening analyses.
4.1.1 Location of Emissions Source and Class I Area(s)
The first step is to identify the location of the emissions source
and the class I area(s) that may be affected. Some of this work will have
been performed as part of the level-1 screening analysis that identified
the minimum distance between the emissions source and the class I area.
The Federal Land Manager(s) of the potentially affected class I
area(s) should be contacted so that important integral vistas (i.e., with
views from inside to outside of the class I area) can be selected for
analysis. All class I areas that may be adversely affected, as indicated
by the level-1 screening test, should be considered in the level-2
analysis.
U.S. Geological Survey maps (scale 1:250,000) should be used to
determine terrain elevations. These maps are recommended as a base upon
which to draw the location of the emissions source, the locations at which
meteorological data were collected, the boundaries of class I areas, and
the particular class I area key observer points and integral vistas iden-
tified for analysis. Also, it would be helpful for later analysis to draw
the boundaries of each of the 16 cardinal (22.5° wide) sectors radiating
from the site of the emissions source.
66
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Elevated terrain features that could potentially block the transport
of a plume toward a class I area should be Identified. (A significant
terrain feature, such as a plateau, ridge, or mountain range, could pre-
vent the direct transport of emissions toward a class I area.) A repre-
sentative effective stack height of emissions should be calculated by add-
ing to the physical stack height the plume rise for neutral conditions and
the 50-percentlie wind speed:
H = h * *h . (p-8)
The neutral plume rise is calculated using the following Briggs plume
rise formula (Briggs, 1969, 1971, 1972):
it 2/3 •*
Ah = 1.6 F (3.5 x ) u"1 , (p-9)
where
Ah = plume rise,
u = average wind speed in the layer through which the plume rises,
F s buoyancy flux
g 1/1 - ambient ) , (values of T in degrees Kelvin)
M Tstack /
g = gravitational acceleration =9.8 m/s^,
v1 = flue gas volumetric flow rate per stack,
14 F5/8 ,1f F < 55 mV3
34 F2/5 ,1f F > 55 mV3
x* E
To this average effective stack height, add the elevation of the proposed
site (above mean sea level) and 500 meters, which is the assumed addi-
tional terrain height that is needed to block plume transport:
67
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Zblock * Zsite * H * 50° m • (P
Shade the areas on the base map with elevations greater than this value.
Trace plausible plume trajectories on this map that bypass the elevated
terrain (shaded areas on the map). Examples of such plume trajectories
are shown in figure 14. Note that stable plume transport directly toward
observers A and B would be very unlikely. Stable flow would follow the
curved trajectories shown in figure 14. Note that a stable plume would
not likely be transported to observer C, althoilgh a stable plume near the
emissions source might be visible to this observer. A straight-line tra-
jectory to observer D in figure 14 is possible.
It should be noted that a plume could be transported directly toward
observers A, B, and C during neutral or unstable conditions; however,
mechanically induced turbulence would increase the mixing of the plume,
and visual impacts would be small.
The distances along these plume trajectories will be used later as
the downwind distance x to the class I area(s) for use in calculating
plume transport times and diffusion.
Elevation profiles of terrain at various azimuths from key observer
points in class I areas that may be affected by the emissions source (see
the example in figure 15) should be prepared. These plots should extend
radially from the observer location to the most distant landscape feature
visible from the given location, or to the average visual range for the
area, whichever is less. From these plots the distance along the line of
sight to various landscape features can be calculated. These plots and
distances will be used in later analyses of plume perceptibility and land-
scape-feature contrast reduction.
4.1.2 Meteorological Conditions
The joint frequency of occurrence of meteorological conditions at the
effective stack height of the emissions 1s needed to estimate the worst-
68
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ELEVATED TERRAIN
BOUNDARIES OF
16 CARDINAL WIND
DIRECTION
SECTORS
OBSERVER
A
OBSERVER
B
OBSERVER
EMISSIONS SOURCE
OBSERVER D
Figure 14.
Example of map showing emissions source, class I areas,
'and stable plume trajectories.
69
-------
OBSERVER
•OBSERVER
Figure 15. Examples of terrain elevation plots.
70
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case meteorological conditions in the area associated with visual impacts
that will be exceeded only about one day per year.
The important meteorological parameters are
> Wind speed
> yiind direction
> Atmospheric stability
> Mixing depth.
It is essential to consider the persistence as well as the frequency
of occurrence of these conditions. For example, plume discoloration will
generally be most intense during light-wind, stable conditions. However,
the transport time to a class I area increases as the wind speed
decreases. As the transport time approaches 24 hours, it is increasingly
probable that the plume will be broken up by convective mixing and by
changes in wind direction and speed; thus it will not be visible as a
plume or a discolored layer. However, since increased haze often occurs
because of secondary aerosols that take time to form in the atmosphere,
visual range reduction may be more significant when transport times to a
class I area are long. Largest increases in general haze (visual range
reduction) resulting from an emissions source might occur if there is
stagnation caused by synoptic meteorological conditions or topographical
factors, or if there is trapping of emissions caused by upslope or down-
slope flow reversals.
Ideally, one would prefer to have a meteorological data base with
detailed spatial and temporal coverage. However, this is rarely possible
because of cost considerations. Several alternative approaches can be
used to fill in missing data, but they all involve making assumptions.
For example, if a complete meteorological data base is available only at
the site of the proposed emissions source, one might assume that condi-
tions at the site are representative of conditions at other locations in
the region. However, in regions of complex terrain, like the example
shown in figure 14, this assumption would not be appropriate. Often, data
71
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collected at ground level are assumed to represent conditions at the
effective stack height, which is a poor assumption when the plume is
several hundred meters above ground or the site is located in complex ter-
rain.
Any assessment of air quality or visibility impacts is limited by the
availability of meteorological data; more detailed assessments require
more detailed and extensive data bases. Detailed visibility assessments,
which are discussed in the next section of this document, require
spatially and temporally resolved meteorological data. The level-1
screening analysis discussed in the previous chapter requires no meteoro-
logical data; rather, conservative assumptions are made regarding worst-
case stability, wind speed, and wind direction. The level-2 screening
analysis assumes that the analyst has at least one year of meteorological
data from the site of the proposed emissions source, a nearby site within
the region, or the class I area(s) potentially affected by emissions.
The types of data bases for the level-2 analysis are listed as
follows, in order of preference:
> Concurrent upper air winds and stability. The best data
base would provide hourly values of vertical temperature
'•gradients from which dispersion coefficients can be
inferred and wind direction and speed vectorially
averaged. If effective stack heights (physical stack
height plus plume rise) are relatively low, these data can
be collected from a meteorological tower. If the effec-
tive stack heights are high, these data would have to be
collected using rawinsondes, tethered balloons, or Doppler
acoustic radar systems. A less desirable data base would
consist of upper-air meteorological data gathered twice
daily, such a;s those collected routinely by the National
Weather Service.
> Separate data sets. For some sites a good data base that
consists of upper-air winds (e.g., from pibals) may be
72
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available without concurrent lapse-rate (vertical tempera-
ture gradient) data. In such situations, one can use
lapse-rate data collected from another location in the
region for the same or different periods for which wind
data were collected. An assumption is made that the sta-
bility at the other location is representative of the site
and the class I area. If stability data are not available
for the same period during which wind data were collected,
the additional assumption must be made that wind frequen-
cies and stability frequencies can be treated as inde-
pendent probabilities, as discussed in chapter 2.
> Surface data. Surface data (e.g., STAR data) may be
appropriate if the effective stack height of the emissions
is low or zero. However, surface data may be inappro-
priate for evaluating the impacts of elevated releases.
If no other data are available, one should use surface
data with full recognition of the potential errors
associated with their use; these errors may be extreme in
complex terrain. If lapse-rate data are not available,
one can estimate stability using the Turner method (1969).
> No data. If meteorological data are not available, the
assumptions regarding meteorology used in the level-1
analysis would be used to assess impact.
The Turner method (1969) should be used to determine stability categories
that can then be used to assess plume dispersion using the oy and o^
curves of Pasquill-Gifford (Turner, 1969). It should be noted that dis-
persion conditions at a given site may be considerably different from the
idealized Pasquill-Gifford representations. Many different estimates of
For the analysis of plume discoloration, these conditions are F
stability and a wind speed that would transport emissions to a class I
area within 12 hours. For the analysis of potential haze due to sulfate
aerosol, one would assume limited mixing conditions with a mixing depth
of 1000 m ana1 a wind speed pf 2 m/s.
73
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oy and oz are available, such as the TVA, Brookhaven, and ASME curves.
However, the Pasquill-Gifford curves are the most generally used and
therefore have been adopted for use in this document. The Pasquill-
Gifford oz values may either overestimate or underestimate actual vertical
diffusion in a given application. If diffusion data are available from
tracer studies or from similar emissions sources in the region, such data
could be used to assess more accurately potential plume visual impacts.
4.1.2.1 Worst-Case Conditions for Plume Discoloration
It should be emphasized that the vertical diffusion (az) of a plume
is the most important diffusion parameter for visibility impact assess-
ments, because the optical thickness of a plume for horizontal lines of
sight is inversely proportional to ozt as shown in equations (19) and
(20). Specification of horizontal diffusion (oj is less important.*
On the basis of the available data base discussed previously, tables
of joint frequency of occurrence of wind speed, wind direction, and
stability class should be prepared that are similar to those shown in
figure 16. These tables should be stratified by time of day. If meteoro-
logical data are available at hourly intervals, it is suggested that these
tables be stratified as follows: 0001-0600, 0601-1200, 1201-1800, and
1801-2400. If data are available twice daily, morning and afternoon data
should be tabulated separately. With this stratification, diurnal varia-
tion in winds and stability are more easily discernible.
This step can be skipped if |CjJ and ^1 from the level-1 analysis are
each less than 0.1.
It should be noted that calculations of plume discoloration using the
plume visibility model (PLUVUE) indicate that plume discoloration
increases as plume ay increases because of increased NO-to-N02
conversion in well-mixed plumes.
74
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MORNING HOURS ONLY (0001-0600); OTHER SETS
OF TABLES FOR OTHER TIMES OF DAY
B
Stability Class F
Wind Speed (m/s)
0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 >10 Total
N
NNE
NE
ENE
E
tS
g S
S SSW
« sw
c WSW
» w
WNW
NW
NNW
Total
Figure 16. Joint frequency distribution tables required to estimate
worst-case meteorological conditions for plume discoloration
-------
On the basis of the maps prepared previously, the analyst should
select the wind direction sector that would transport emissions closest to
a g^ven class I area observer point so that the frequency of occurrence of
impact can be assessed as discussed below. For example, in the schematic
diagram shown in figure 17, west winds would transport emissions closest
to observer A, whereas either west-southwest or west winds would transport
emissions closest to observer B. Observer C would be affected by emis-
sions transported by west-northwest and northwest winds, but primarily by
west-northwest winds.
For the situations influenced by complex terrain, such as the example
shown in figure 14, the determination of this worst-case wind direction
and its frequency of occurrence is much more difficult. The analyst
should use professional judgment in this determination.
The determination of the worst-case wind direction and its frequency
of occurrence should be made on the basis of the following factors:
> Location(s) for which meteorological data were collected
relative to terrain features, emissions source, and
potentially affected class I areas.
> Likely plume trajectories for each wind direction (and
possibly wind speed and stability) based on either data or
professional judgment. For example, potential channeling,
convergence, and divergence of flows should be assessed.
The next step is to construct a table (see the example in table 1)
that shows worst-case dispersion conditions ranked in order of decreasing
severity and the frequency of occurrence of these conditions associated
with the wind direction that could transport emissions toward the class I
area. Dispersion conditions are ranked by evaluating the product o^u,
where oz is the Pasquill-Gifford vertical diffusion coefficient for the
given stability class and downwind distance x along the stable plume tra-
jectory identified earlier, and u is the maximum wind speed for the given
wind speed category in the joint frequency table. The dispersion condi-
76
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EMISSIONS
SOURCE
Figure 17.-
Schematic diagram showing emissions source, observer
locations, and wind direction sectors.
77
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TABLE 1. EXAMPLE TABLE SHOWING WORST-CASE METEOROLOGICAL CONDITIONS
FOR PLUME DISCOLORATION CALCULATIONS
Dispersion
Condition
(Stability
wind speed)
F, 1
E, 1
F, 2
F, 3
E, 2
F, 4
D, 1
F, 5
E, 3
oz u
(m2/s)
90
175
180
270
350
360
430
450
525
Transport
Time
(hrs)
56*
56*
19*
11
19*
8
56*
6
11
Frequency of Occurrence of
Given Dispersiori Condition
Associated with Worst-Case
Wind Direction* for Given
Time of Day
(percent)
0-6
0.2
0.3
0.2
0.2
0.4
0.3
0.0
0.1
0.5
6-12
0.1
0.2
0.1
0.2
0.3
0.2
0.2
0.1
0.3
12-18
0.0
0.1
0.0
0.0
0.0
0.0
0.5
0.0
0.1
18-24
0.2
0.2
0.2
0.2
0.2
0.2
0.1
0.1
0.3
Frequency and
Cumulative
Frequency
(percent)
f
0.0
0.0
0.0
0.2
0.0
0.3
0.0
0.1
0.5
cf
0.0
0.0
0.0
0.2
0.2
0.5
0.5
0.6
1.1
Transport times to class I areas during these conditions are longer than 12
hours, so they are not added to the cumulative frequency summation.
For a given class I area.
78
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tlons are then ranked in ascending order of the value ozu. This is illus-
trated with an example in table 1. The downwind distance in this hypothe-
tical case is assumed to be 100 km. Note that F,l (stability class F
associated with wind speed class 0-1 m/s) is the worst dispersion condi-
tion, since it has the smallest value of ozu (90 nrVs). The second worst
diffusion condition in this example is E,l, followed by F,2, F,3, and so
on.
The next column in table 1 shows the transport time along the minimum
trajectory distance from the emissions source to the class I area, based
on the midpoint value of wind speed for the given wind speed category.
For example, for the wind speed category, 0-1 m/s, a wind speed of 0.5 m/s
should be used to evaluate transport time; for 1-2 m/s, 1.5 m/s; and so
on. The times rtecessary for a plume parcel to be transported 100 km are
56, 19, 11, 8, and 6 hours for wind speeds of 0.5, 1.5, 2.5, 3.5, and 4.5
m/s, respectively.
For the level-2 screening analysis, we assume it is unlikely that
steady-state plume conditions will persist for more than 12 hours. Thus,
if a transit time of more than 12 hours is required to transport a plume
parcel from the emissions source to a class I area for a given dispersion
condition, we assume that plume material is more dispersed than a standard
Gaussian plume model would predict. This enhanced dilution would result
from daytime convective mixing and wind direction and speed changes.
The objective of this tabulation of plume dispersion conditions is to
identify the worst-case meteorological conditions. The joint frequency of
occurrence of these worst-case meteorological conditions, associated with
high background ozone concentrations and high background visual range,
would be calculated by multiplying independent probabilities as discussed
in chapter 2. This would define the frequency of occurrence of worst-case
visual impact conditions. To obtain the worst-case meteorological condi-
tions, i-t is necessary to determine the dispersion condition (a given wind
speed and stability class associated with the wind direction that would
transport emissions toward the class I area) that has a ozu product with a
79
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cumulative probability of 1 percent. In other words, the dispersion con-
dition is selected such that the sum of all frequencies of occurrence of
conditions worse than this condition totals 1 percent (i.e., about four
days per year). Dispersion conditions associated with transport times of
more than 12 hours are not considered in this cumulative frequency for the
reasons stated above.
This process is illustrated by the example shown in table 1. It is
seen that the first three dispersion conditions would cause maximum plume
visual impacts, because the ozu products are lowest for these three condi-
tions. However, the transport time from the emissions source to the class
I area associated with each of these dispersion conditions is greater than
12 hours. With the fourth dispersion condition (F,3), emissions could be
transported in less than 12 hours. The frequency of occurrence (f) of
this condition is added to the cumulative frequency summation (cf). For
this hypothetical example, the meteorological data are stratified into
four time-of-day categories. The maximum of each of the four frequencies
is used to assess the cumulative frequency. This is appropriate since we
are concerned with the number of days during which, at any time, disper-
sion conditions are worse than or equal to a given value.
Note that the worst-case, stable, light-wind dispersion conditions
occur more frequently in the nighttime hours. In our example, the fol-
lowing additional worst-case dispersion conditions add to the cumulative
frequency: F,4; F,5; and E,3. Dispersion conditions with wind speeds
less than 2 m/s (F,l; E,l; F,2; E,2; and D,l) were not considered to cause
an impact because of the long transit times to the class I area in this
example. Thus, their frequencies of occurrence were not added to the
cumulative frequency summation. The result of this example analysis is
Nighttime visual impacts, such as obscuration of the view of the moon or
the Milky Way, are not usually a concern. However, significant visual
impacts could be caused in the morning after a period of nighttime
transport.
80
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that dispersion condition E,3 is associated with a cumulative frequency of
1 percent, so we would use this dispersion condition to evaluate worst-
case visual Impacts for the level-2 screening analysis for this example
case.
It should also be noted that if the observer point in the class I
area is on or near the boundary of one of the 16 cardinal wind direction
sectors, it may be appropriate to interpolate the joint frequencies of
wind speed, wind direction, and stability class from the two wind direc-
tion sectors, on the basis of the azimuth orientation of the observer
relative to the center of the wind direction sectors.
4.1.2.2 Worst-Case Conditions for General Haze*
A similar procedure should be used to identify the potential worst-
case limited mixing conditions for the region used in calculating worst-
case haze increases caused by sulfate aerosol formed from S02 emissions.
Most significant increases in general haze caused by emissions from a
given source are likely to occur after a long period of transport during
light-wind conditions when the vertical mixing is limited by a capping
stable layer. In the level-1 analysis, we assumed that limited mixing
conditions with a mixing depth of 1000 m and a wind speed of 2 m/s per-
sisted for two days without precipitation (which would wash out par-
ticulates, S02 and S04=). In the level-2 analysis, assumptions appro-
priate to the area being analyzed should be used.
Two alternative approaches to this analysis can be considered. The
first assumes concurrent mixing depth, wind speed and wind direction data
for the site or region. The second assumes the absence of these data.
The first approach is more time-consuming, but presumably more accurate,
than the second.
This step can be skipped if |C3| from the level-1 analysis is less than
0.1.
81
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Let us consider the first approach. If one has vertical temperature
gradient data for a region, one can calculate maximum daily mixing depths
in a manner similar to that used by Holzworth (1972). These data should
be sorted to identify periods without precipitation for at least two
days. The remaining occurrences should be used to generate joint fre-
quency tables similar to those shown in figure 18. Occurrences are sorted
into different categories of maximum 48-hour mixing depth and 48-hour
vector-average wind direction and wind speed.
The vector-average wind direction and speed (i.e., the resultant
wind) are defined by calculating a position vector as follows:
f 48 hr
r = | 7 (x,y,z,t) dt
where "r is the position vector and V (x,y,z,t) is the spatially and tem-
porally dependent wind vector for the plume parcel emitted by the
source. The vector-average wind direction is defined by the direction of
the vector 7 and the vector-average wind speed is
The next step parallels the procedures used to identify the worst-
case meteorological conditions for plume discoloration. The analyst
should construct a table of worst-case limited mixing conditions ranked in
decreasing order of severity (increasing product of mixing depth Hm and
wind speed "u). Table 2(a) shows how such a table might be constructed.
Different wind directions in which a class I area is located are iden-
tified in this table from a map similar to the example in figure 19. This
map shows 16 wind direction sectors and circles with radii corresponding
to "u values of 1, 2, 3, and 4 m/s (r = 173, 346, 518, and 691 km,
respectively). For each limited mixing condition (IT Hm) and wind direc-
tion combination, the number of nonoverlapping 48-hour episode occurrences
in a year is tabulated. If a class I area is located within the bounds
82
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1 > 2500 m
[ 2001-2500 m
I 1501-2000 m
| 1001-1500 m
| 501-1000 m
MIXING DEPTH: 0-500 m
24-Hour Average Wind Speed (m/s)
0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 >10 Total
N
NNE
NE
ENE
E
o SE
£ SSE
t s
5 SSW
•o SW
c WSW
* w
WNW
NW
NNW
Total
"™
•* *
M-
^~
MM
Figure 18. Joint frequency distribution tables required to estimate worst-case
meteorological conditions for visibility impairment due to
S02 emissions.
83
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TABLE 2. EXAMPLE TABLE SHOWING WORST-CASE LIMITED MIXING CONDITIONS FOR HAZE CALCULATIONS
(a) Based on Site/Regional Data
Limited Mixing
Condition
(u, HJ*
(m2/s)
Number of Occurrences of
Indicated Limited Mixing Condi-
tion in a Year Associated with
Wind Direction in Given Sector
1; 500
2; 500
1; 1,000
3; 500
1; 1,500
2; 1,000
4; 500
5; 500
3; 1,000
2; 1,500
500
1,000
1,000
1,500
1,500
2,000
2,000
2,500
3,000
3,000
SWT
0
0
0
0
0
0
(1)^
0 r
(2)§
1
w
0
0
0
0
0
0
0
0
0
1
WNW
o •
0
0
0
0
0
1
0
0
0
NNW
0
0
0
0
0
0
0
0
1
0
ENE
0
0
0
0
0
0
0
0
0
0
Impact Frequency
and Cumulative
Frequency
f
0
0
0
0
0
0
1
0
1
2
cf
0
0
0
0
0
0
1
1
2
4
In units of m/s for u and m for Hm.
Wind direction sector is defined as the direction from which the wind blows, so
areas A and B are affected by SW winds because they are located in the NE sector.
Parentheses indicate that, though a given combination of u, Hm, and wind direction
occurred, no class I areas were located within the corresponding sector-distance.
84
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TABLE 2 (Concluded)
(b) Based on HoIzworth (1972) Data (example 1s based on Wlnslow, Arizona data)
ited Mixing
Condition
(uf Hj
2; 500
2; 1,000
4; 500
2; 1,500
6; 500
2; 2,000
4; 1,000
|; 1,500
B; 1,000
B; 2,000
K; 1,500
1; 2,000
Number of Days per
u "m
(•#)
1,000
2,000
2,000
3,000
3,000
4,000
4,000
6,000
6,000
8,000
9.000
12,000
Episode-Days in Five- Year
Period after a Minumum
of 48-hours Transport
2
22
33
2
1
0
80
54
21
11
21
30
Number of Sectors
with Class I Areas*
4
4
3
4
2
4
3
3
2
3
2
2
Year 1n
Area
f§
0.10
1.10
1.24
0.10
0.03
0.00
3.00
2.03
0.53
0.41
0.53
1.13
a Class I
Sector
cf
0.10
1.20
2.44
2.54
2.57
2.57
2.57
7.60
8.13
8.54
9.07
10.20
units of m/s for u and m for H,,,.
nber of wind direction sectors with class I areas within radii corresponding to given
jnd speed class (0-2, 2-4, 4-6, m/s).
Jese numbers are calculated as follows:
(episodes/five-year period) (no. of sectors)
(5 one-year periods/five-year period) (16 sectors)
85
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•r = 691 km
EMISSIONS-
SOURCE
H
• F
Figure 19. Example map showing class I areas In region around emissions
source and wind direction/speed sectors. (Note: Class I
area locations are shown at lettered points.)
86
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defined by the wind direction sector boundaries and the wind speed class
radii, the occurrence is added to a cumulative frequency total. We
proceed until we have identified the worst-case condition with a cumula-
tive frequency of four occurrences in a year. In the example shown in
table 2(a), this worst-case condition is a wind speed of 2 m/s and a mix-
ing depth of 1500 m.
The second approach should be used if site mixing depth data are not
available or if analytic resources and time are limited. This approach
uses information from Holzworth (1972), which shows, among other things,
the number of episodes and episode-days without significant precipitation
in a five-year period, with mixing depths and wind speeds less than given
values persisting for at least two days.
Using this second, simpler approach, we tabulate the number of epi-
sodes in five years with given conditions as shown in table 2(b).
Holzworth (1972) gives cumulative frequencies (number of episodes and
episode-days) of u < u1 and H,^ < Hm'. For our purposes we need to convert
these to frequencies in a given u and ^ category, as shown in table
2(b). The number of episode-days in a five-year period within a given
limited mixing category is determined from Holzworth (1972) in the manner
illustrated in table 3. First, the number of episodes (cfe) and the
number of episode-days (cf^) in five years is tabulated for each mixing
depth and wind speed category. The number of days in five years that were
preceded by the given limited mixing condition persisting at least 48
hours is calculated from the difference, cfd - cfe. To convert these
cumulative frequencies to frequencies within each mixing depth/wind speed
category, one must subtract the frequencies of the appropriate categories
as shown in table 3. We convert these frequencies to episode-days per
year within a given wind direction sector and wind speed class radii in
which class I areas are located as shown in the footnote in table 2(b).
We determine an episode-day cumulative frequency equivalent to four days
per year. For the example shown 1n table 2(b), this worst-case limited
mixing condition is u = 4 m/s and Hm = 1000 m. If the cumulative fre-
quency of occurrence of these extreme limited mixing conditions is less
87
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TABLE 3. EXAMPLE TABLES SHOWING COMPUTATION OF DAYS IN A FIVE-
YEAR PERIOD WITH THE GIVEN LIMITED MIXING CONDITION
Upper Limits of
Limited Mixing
Category
u
(m/s)
2
4
6
2
4
6
2
4
6
2
4
6
(m)
500
500
500
1000
1000
1000
1500
1500
1500
2000
2000
2000
Number of Occurrences
in a Five-Year Period
(from Holzworth, 1972)
Episodes Episode-days
2
13
13
13
37
42
17
52
62
17
59
75
4
48
49
37
174
197
43
245
294
43
263
348
Number of Days
in Five Years
Preceded by at
Least 48 Hours of
a Given Limited
Mixing Condition
Cf2+ = cfd - cfe
2
35
36
24
137
155
26
193
232
26
204
273
Hind Speed
(m/s) 0-500
Nixing Depth (•)
500-1000 1000-1500 1500-2000
0-2
2-4
4-6
2
2
1
35
33
(35-2)
2
36
1
(36-35)
3
24
22
(24-2)
4
137
80
(137-35-22)
5
155
17
(155-36-22-80)
6
26
2
(26-24)
7
193
54
(193-137-2)
8
232
21
(232-155-2-54)
9
26
0
(26-26)
10
204
11
(204-193-0)
11
273
30
(273-232-11-0)
J2
Note: Examples are based on data for Ulnslow, Arizona,
from Holzworth (1972).
cfd"*e
OF
CALCULATION
-------
than four days per year for the given region, we use the annual median
mixing depths and wind speeds for the region (also given in Holzworth
[1972]).
Finally, regardless of which method is used, the seasonal average
afternoon wind speeds and mixing depths for the region should be tabulated
on the basis of Holzworth (1972) for later use.
4.1.3 Background Ozone Concentration
As noted in chapter 2, an important input parameter to the visibility
model is the background ozone concentration, that is, the concentration of
ozone outside the plume.
Since we are concerned with background ozone concentrations at the
effective stack height, which may be several hundred meters above ground,
we must interpret ground-level ozone concentration data with care. In
their analysis of long-term ozone concentration data at remote U.S. sites,
Singh, Ludwig, and Johnson (1978) reported that there is a significant
diurnal variation in ozone concentrations at the surface because of the
surface depletion of ozone. They reported a significant reservoir of
ozone in the free troposphere varying in concentration from about 30 ppb
in the winter to about 60 ppb in the summer. The tropospheric ozone is
rapidly mixed to the ground during the daytime; this causes surface con-
centrations near the free tropospheric value. However, at night and in
early morning, ozone is no longer mixed to the ground because of the
development of a ground-based stable layer. During this period, ground-
level ozone concentrations gradually decrease as a result of a surface
depletion mechanism. In relatively remote, unpolluted regions, one would
not expect a significant anthropogenic source of ozone. In figure 20, the
vertical ozone structure and diurnal and seasonal variations in ozone con-
centration are shown schematically.
Since we are concerned with ozone concentrations at plume altitude 1n
visibility calculations, 1t is appropriate to use the daily maximum value
89
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Top of th* ofttrneen
Ioy*r
110
• 0
e
Ik)
0, Diurnal •refilt
Free tropotphort
1X0
5 10 19 SO IS
Local timt, ft
120
too
• 0
• 0
so
) Oirict Oj transport
Item urpan ctntirt
I0cal wont tynth«ii
(NO, intrusion)
Due to natural NO,
J I
MOV JAN MA*
4UI tl^t HOV
Source: Singh, Ludwig, and Johnson (1978).
Figure 20. A schematic of the vertical 03 structure and its
diurnal and seasonal variations at remote sites.
90
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of the surface concentration to represent the daily average concentration
at plume altitude, as shown in figure 20(a).
We select a median background ozone concentration for the assessment
of worst-case visual impacts, so, by definition, the frequency of occur-
rence of ozone concentrations higher than that assumed is 50 percent.
This is done so that when the cumulative frequencies of occurrence of
meteorological conditions worse than the assumed worst-case meteorological
conditions are multiplied by the corresponding frequencies of high back-
ground ozone concentration and visual range, the resulting cumulative fre-
quency is the equivalent of one day per year. Thus, we have
(cumulative frequency of assumed worst-case meteorological conditions)
x (cumulative frequency of assumed background ozone concentration)
x (cumulative frequency of assumed background visual range)
= 0.01 x 0.50 x 0.50 x 365 days/year z 1 day/year.
4.1.4 Background Visual Range
As noted previously, we want to select the median background visual
range to analyze worst-case visual impact conditions. The impact-
magnitude calculations described in the next section are based on the
assumption that visual range is calculated at a wavelength X of 0.55 un:
3.912
vO " bext (x = °-55
Since there can be a significant wavelength dependence of bext, it is
important that the median background visual range for the site and region
is based on spectral measurements at 0.55 im. Such measurements can be
made with telephotometers or nephelometers equipped with narrow band-pass
filters. If such data are not available, use the estimates of median
regional visual range shown in figure 13.
91
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4.2 HAND CALCULATION OF WORST-CASE VISUAL IMPACTS
From the procedures discussed previously, the analyst will have iden-
tified the following conditions for calculation of worst-case impacts:
> Worst-case (1-percentile) plume dispersion condition.
- Worst-case wind direction (one of sixteen 22.5°
sectors).
- Wind speed.
- Pasquill-Gifford stability class.
> Worst-case (1-percentile) and seasonal average limited
mixing condition.
- Wind speed.
- Mixing depth.
> Median (50-percentile) background ozone concentration.
> Median (50-percentile) background visual range.
> Distances to terrain objects for various line-of-sight
azimuths.
> Downwind distance x along plume trajectory.
In this section we discuss the calculation of visual impact parame-
ters on the basis of those worst-case conditions appropriate for a level-2
visibility screening analysis. We suggest four different alternatives for
calculating magnitudes of worst-case visual impacts:
> Hand calculations of plume contrast and sky/terrain con-
trast reduction using equations (10) and (14) from
chapter 2, and procedures presented in this section.
> Reference tables of plume discoloration parameters corres-
ponding to various N02 line-of-sight integrals.
> Reference figures of visual range reduction caused by
emissions sources of different sizes for various meteoro-
logical conditions.
> Computer model calculations using PLUVUE or some other
equivalent visibility model.
92
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The analyst can choose which of these methods to use for a level-2
screening analysis, depending on personal preference. However, more
accurate estimates (with less conservatism) are possible with the use of
computer model calculations. Assessments using different alternative
methods can be cross-checked.
He can compute the magnitude of visibility impact corresponding to
the worst-case conditions identified earlier in this section by a series
of formulas presented here. Some of these calculations are needed to use
the reference tables and to set up input for the computer model.
4.2.1 Determining the Geometry of Plume, Observer, Viewing Background,
and Sun
In the previous section we discussed the procedure for identifying
the worst-case meteorological conditions used in the calculation of visi-
bility impacts. This condition was selected so that on only one day per
year (on the average) would conditions be worse than those selected for
analysis. As the basis for the selection of this condition, we considered
the frequency of occurrence of wind directions that would carry emissions
within the 22.5* sector centered on the observer, as shown schematically
in figure 21.
Thus, we have identified the cumulative frequency (i.e., the fre-
quency of occurrence of conditions worse than the given value) of wind
directions within the worst-case wind direction sector associated with (1)
wind speeds less than, (2) stabilities greater than, (3) background ozone
concentrations greater than, and (4) background visual ranges greater
than, the given values selected for the worst-case impact evaluation.
Because we wish to compute the magnitude of plume visual impact, it
is appropriate to consider the plume orientation resulting in the smallest
impact associated with the worst-case wind direction sector. Thus, we
consider a plume'centerline at the edge of the 22.5° sector centered on
93
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OBSERVER IN
CLASS I AREA
LOCUS OF ALL PLUME CENTER-
LINES ASSOCIATED WITH
WORST-CASE WIND DIRECTION
SECTOR
•EMISSIONS SOURCE
Figure 21. Locus of plume centerlines within worst-case
wind direction sector.
94
-------
the observer, as shown in figure 22. Thus, the minimum distance between
the observer and the plume centerline is
= °'199 X
where x is the downwind distance along the plume centerline from the emis-
sions source to the parcel that is observed, as shown in figure 22.
For the worst-case plume discoloration condition, the plume is
assumed to have a Gaussian distribution in the vertical direction, with
vertical dimensions as a function of the a corresponding to the given
worst-case stability class and downwind distance x. For level-2 screening
performed on the basis of hand calculations, we further assume that the
plume material is uniformly mixed in the horizontal direction within the
22.5" sector. Thus the plume width at a given downwind distance is twice
or °'398 *•
For the worst-case general haze conditions one must remember the
assumption that plume material has been transported for two days. There-
fore, for the evaluation of increases in haze resulting from S02 and par-
ticle emissions during worst-case 48-hour episodes of limited mixing, we
assume that the plume width is 100 km. Several studies suggest that plume
spread is a function of travel time and that this 100 km width is a
reasonable representation for a 48-hour travel time (see, for example,
model calculations of Liu and Durran, 1977, and field data of Randerson,
1972).
For the level-2 analysis (based on hand calculations), we also assume
that the plume width is constant within the field of view, as shown in
figure 23. This plume width equals 2rp_min (0.398 x, or 100 km). Both
the plume optical thickness, Tpiume» and the distance to the plume center-
line are inversely proportional to the size of the angle a shown in figure
95
-------
11.25
-EMISSIONS SOURCE
OBSERVER A
PLUME MATERIAL
Figure 22. Observer-plume orientation for level-2
visibility screening analysis.
96
-------
23. Thus,
T, (-)- We. (••
plumev y sTrTo
r 0
"m1n
px ' sin a
Also, the plume optical thickness between the observer and a given
viewed object is a function of the object-observer distance rQ:
Tplume(ro' o)
1f ro < 2rp(°>
The distances rQ and the azimuths for various terrain viewing objects
identified using the procedure discussed previously in this section (see
figure 15) should be tabulated. The corresponding values of a and scat-
tering angle e should be identified in this table also. The scattering
angle 9 for horizontal lines of sight can be determined as follows (Duffie
and Beckman, 1974):
cos 6 = cos 6 sin A sin H + sin 6 cos 4> cos A
- cos 6 sin <(> cos A cos H , (p-11)
where
A = azimuth of the line of sight from observer to viewed
object (e.g., A * 0" for the line of sight directly
to the north),
6 = declination,
97
-------
OBJECT
to
00
PLUME MATERIAL
'//// //////
PLUME CENTERLINE //.
OBSERVER
Figure 23. Plan view of assumed plume-observer geometry for
level-2 visibility screening calculations.
-------
2 23.45 sin /360 ^ n degrees] ,
n H number of the day of the year (e.g., 1 January is
n-1),
4> = latitude of the observer,
H = hour angle, solar noon being zero, each hour equiva-
lent to a 15* displacement, mornings positive and
afternoons negative.
Note that stable plumes are usually viewed in the morning at, or
shortly after, sunrise. The scattering angle 9 at sunrise at a spring or
autumnal equinox is determined for 6 = 0° and H = 90* as follows:
cos 0 = sin A
Thus, for these dates and this time
IA - 90°| , if 90° < A < 270°
e =
450° - A , if A > 270°
The value of the scattering angle and the appropriate line-of-sight
azimuth A should also be evaluated for the following values of o: 30",
45*, 60*, 90*, 120*, 135*. and 150*. Note that both A and o are azimuthal
angles descriptive of the line of sight. A is referenced to north and o
is referenced to the plume centerline.
4.2.2 Calculating Plume Optical Depth
We start with known emission rates of primary particulate matter,
NOX, and S02 from the source. To convert these quantities to plume opti-
cal depth (T), we must know
> Size distribution and density of emitted particles.
> Size distribution and density of secondary sulfate aero-
99
-------
sol.
> Fraction of NOX and S02 emissions converted to N02 or sul-
fate (S04=) aerosol at a given downwind distance (or
transport time).
> Vertical distribution of plume material.
> Wind speed.
4.2.2.1 Effects of Primary Particulate Emissions on Optical Depth
If the size and density of primary particle emissions are known, we
can compute the plume flux of the scattering coefficient from the follow-
ing formula:
1160 Qnar*(bcraf/V)
Q , , Pdrt scat
yscat-part
where
^scat-part - Plume ^lux 0
-------
0.10
GEOMETRIC o = 2
STANDARD 9
DEVIATION
ACCUMULATION
MODE
0.001
0.1
1.0 10.0
Mass Median Diameter (DG)
Source: Latimer et al. (1978).
Figure 24. Scattering-to-volume ratios for various size distributions
101
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If one does not know the primary particle size distribution and den-
sity, one can assume the values used for the level-1 analysis—a mass
median diameter DG of 2 in, a geometric standard deviation og of 2, and a
density of 2.5 g/cm3 (Schulz, Engdahl, and Frankenberg, 1975). For this
distribution we have (bscat/V) = 0.025, and therefore
"scat-part ' U'6 "part . (p-13)
Another alternative is to use the known stack opacity to calculate
the plume scattering coefficient.* Sometimes the stack opacity is known
with more precision than is the mass emission rate for primary par-
ticles. If both the stack opacity and the particle mass emission rate are
known, we can compute the appropriate size distribution that will provide
a match. The stack opacity is defined as follows:
Opacity = 1 - e stack , (p-14)
where T.tark = scat-part ^ 0 E inside stack diameter, and v H flue gas
9la<~IV Q y
stack exit velocity.
We can solve for the scattering coefficient flux per stack as fol-
lows:
Qscat-part = 'D v "^ ' °Pac1t^ • ^'l^
For many facilities, emissions regulations limit stack opacity to 20
percent. For such facilities
A caution is in order here. If wet scrubbers are used or if hygroscopic
material or condensable gases are emitted from the source, it may not be
appropriate to calculate the plume flux of scattering coefficient from
stack opacity because particles may quickly grow and form as flue gas
temperature drops.
102
-------
Qscat-part " 'D v ^l " °'2°) = °-22 D v • (P
The total plume scattering coefficient flux is the sum of the contri-
butions from all stacks in the facility. Note, however, that as a result
of differences in stack height or plume rise for different stack emis-
sions, stable plumes from different elevations in the facility may be at
different elevations, without overlap. In such cases, for the calcula-
tion of stable conditions, one would use the maximum single-stack scatter-
ing coefficient flux only, not the sum over all stacks. This would be
true for N0£ fluxes also. For the calculations of increases in haze
caused by S^ and particle emissions during limited mixing conditions,
however, one should use the emissions over all stacks because all emis-
sions are assumed to be uniformly mixed within the mixed layer.
If one has both the mass emissions rate and the stack opacity, one
can solve these equations for (bscat/V), assuming a particle density of
2.5 or some other appropriate value, and one can use figure 24 to deter-
mine the corresponding size distribution.
The scattering coefficient flux is calculated on the basis of a wave-
length X of 0.55 un. The scattering coefficient (resulting from particles
only) at any wavelength can be calculated from the following equation:
where n is given in table 4 as a function of mass median diameter for a
size distribution whose geometric standard deviation is og = 2.
Note from table 4 that for particle size distributions with mass
median diameters larger than about 1.5 nn, the scattering coefficient is
independent of wavelength over the visible spectrum. However, for a typi
cal submicron aerosol with a mass median diameter of 0.3 un, the scatter-
ing coefficient at X = 0.4 un (the blue end of the spectrum) is 2.5 times
-»
larger than that at X = 0.7 un (the red end).
103
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TABLE 4. WAVELENGTH DEPENDENCE OF SCATTERING COEFFICIENT
AS A FUNCTION OF PARTICLE SIZE DISTRIBUTION
Mass Median
Diameter DG
(un)
0.1 2.8
0.2 2.1
0.3 1.6
0.4 1.2
0.5 1.0
0.6 0.7
0.8 0.5
1.0 0.2
1.5 0
Geometric standard deviation og = 2.
t n is defined as follows: b^f^) = b^X.,)
(appropriate for 0.4 < X< 0.7 un).
104
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The corresponding plume fluxes of scattering coefficients resulting
from sulfate aerosol, and absorption coefficients resulting from N02, are
more difficult to calculate since one has to consider the rate of forma-
tion of sulfate or N02 from S02 and NOX emissions.*
4.2.2.2 Effects of Nitrogen Dioxide on Optical Depth
We first consider the N02 absorption coefficient plume flux. We
assume that, for the two-day limited mixing stagnation case, all N02 is
scavenged by reactions with the hydroxyl radical (OH«). forming nitric
acid vapor (HN03), or from surface deposition. However, for the stable
plume transport case used to calculate worst-case plume discoloration,
nitric oxide (NO) emissions will react with background ozone and oxygen to
form N02.
The fraction of NOX emissions that is converted to N02 can be calcu-
lated with formulations used in the visibility computer model (see Latimer
et al., 1978). This fraction is dependent on the spatial and temporal
variation in ultraviolet radiation, background ozone, and plume S02 and
NOX concentrations. However, for stable, nighttime transport cases, a
reasonable, somewhat conservative estimate of this fraction can be made as
follows: first, we assume that NOX emissions are uniformly distributed
horizontally over a 22.5" sector. Thus, NOX concentrations can be calcu-
lated as follows:
QNO
[NO J
X (2*)1/2ou [2 tan
For those who will use the computer model or the reference figures based
on the computer model runs, these calculations of N02 and SO^ formation
can be omit ted".
105
-------
This can be simplified, using appropriate conversion factors for the units
indicated, as follows:
6.17 QNQ
[NOJ = —„ ..„ x , (p-18)
x ozux
where
[NOX] s plume centerline NOX concentration (ppm),
QNg = mass emissions rate of NOX, expressed as N02
(metric tons per day),
oz = Pasquill-Gifford dispersion coefficient at down-
wind distance x,
u = wind speed (m/s),
x = downwind distance.
For example, this formula yields an NOX concentration of 0.034 ppm
100 km downwind from a 100 metric ton/day source during F stability and
2 m/s wind conditions. Using a simplified formulation from Latimer et al.
(1978), appropriate for stable nighttime transport and early morning
situations, we can calculate N02 concentrations in the plume as follows:
[N02] = <
if [N0x] > h
[N0x] , if [N0x] < h
(P-19)
where
[N02] = plume centerline N02 concentration (ppm),
h = 0.1 [NOX] + [03],
[NOX] = as defined above,
[03] = background ozone concentration (ppm).
For the example shown above, if the background ozone concentration is
a typical value of 0.04 ppm, we calculate an N02 concentration of 0.034
ppm, indicating that complete conversion of NO to N02 occurred.
106
-------
For viewing situations in which the sun is high above the horizon,
this formula overestimates N02 concentrations. For such applications,
either the visibility model or the following formulation should be used to
obtain more accurate determinations (Latimer et al., 1978):
[N0?] = 0.5
[NO]
X
j - J ([NOX] + h + j)2 - 4[NOx]h
(p-20)
where
j = 2.3 x 1CT2 exp (-0.38/cos Zs);
Zs = solar zenith angle, the angle between direct solar rays
and the normal to the earth's surface (e.g., Z$ = 90° for
sunrise or sunset; Zs = 0° for sun directly overhead);
[N02], [03], [NOX], h are defined as above.
The optical depth resulting from N02 is simply
TNQ = 0.398 [N02](x)(babs/ppm) , (p-21)
where x = downwind distance (km), and (babs/ppm) = light absorption per
ppm N02 (km~
The value of (babs/ppm) for N02 as a function of wavelength is plot-
ted in figure 25. Note the extreme variation with wavelength (the plot is
on logarithmic paper). Light absorption by N02 is more than two orders of
magnitude larger at the blue end of the visible spectrum (X = 0.4 un) than
at the red end (X = 0.7 \tn). The values at the three wavelengths that we
will use later to calculate contrasts are as follows:
107
-------
0.01
0.4
0.5
0.6
0.7
Wavelength x
Note: Based on data from Nixon (1940).
Figure 25. Wavelength dependence of light absorption of nitrogen dioxide (N02).
108
-------
babs/ppm (km"*ppm"*)
0.40 l.7i
0.55 0.31
0.70 0.017
4.2,2.3 Effects of Secondary Sulfate Aerosol on Optical Depth
The scattering coefficient for sulfate aerosol is determined from an
empirical formula (Latimer et al., 1978):
3 _2.5 x IP"6 -
b / ( uq/m ) I _. y
DscatMvg/ni 'U = 0.55 wn 1 - (RH/lOO)
where RH is the average relative humidity (in percent) for the area. If
this relative humidity is not known for the given area, assume 40 percent
and 70 percent for the western and eastern United States, respectively.
This sulfate aerosol is assumed to have a size distribution with a mass
median diameter of 0.3 vm and a geometric standard deviation of 2.
The sulfate aerosol mass flux in the plume at a given distance down-
wind is calculated from the emission rate of SO as follows:
* "d> «;
--H v*f T R.dy (
where
. s plume mass flux of sulfate aerosol,
4 -
fMW s ratio of molecular weights of $04" and S02
= 96/64 = 1.5,
109
-------
kf = 24-hour average pseudo-first-order rate constant
for S02 conversion to S04= in the atmosphere,
kd = 24-hour average pseudo-first-order rate constant
for surface deposition = v^/H^,,
t = plume parcel transport time (for the level-2
analysis we assume t = 48 hours),
vd = 24-hour average S02 deposition velocity (we
suggest using vd = 0.5 cm/s),
Hm = mixing depth.
On the basis of calculations of homogeneous oxidation rates by
Atlshuller (1979), we suggest that the following values be used for the
24-hour average S02-to-S04= pseudo-first-order rate constant kf.
kf
Season (%/hr)
Winter 0.1
Spring, autumn 0.2
Summer 0.4
The analyst should use the appropriate values of the mixing depth,
Hm, for the limited mixing worst-case and for the seasonal-average condi-
tions that were identified by the procedure described previously.
We may combine equations for S04= mass flux and scattering coef-
ficient per mass concentration to obtain a formula for the SO^ scattering
coefficient plume flux. This formula, with appropriate conversion factors
for the units shown, is as follows:
(P'22)
- RH/100)
no
-------
where k1 = kf + 1800/Hm, and kf is taken from the tabulation shown above,
Qso is in metric tons per day, RH is in percent, and Hm is in meters.
The plume scattering coefficient flux values for primary particle
emissions and for sulfate aerosol formed from S02 emissions can be conver-
ted to plume optical thickness through division by the appropriate factor.
_ ^scat-part /
for Gaussian vertical profiles (e.g., the worst-case stable plume condi-
tion), and
^scat-part + ^scat-SO.
T , = _! (p-24)
aerosol uH
m
for vertically uniformly mixed plumes in the mixed layer 0 < Z < Hm (e.g.,,
the worst-case and seasonal-average limited mixing conditions).
From the equations presented thus far, the analyst will be able to
calculate the following optical thickness (T) values for any wavelength X:
> TNQ and tpart for the worst-case plume dispersion condi-
tions (assume no sulfate formation for these worst-case,
light-wind, stable conditions).
> Taeroso-| for worst-case limited mixing conditions and each
of the seasonal-average limited mixing conditions.
4.2.3 Calculating Phase Functions
The phase function, defined in equation (1) of chapter 2, describes
the fraction of total light scattered by a given plume or background
in
-------
atmosphere parcel in the direction defined by the scattering angle e. A
scattering angle 9 of 0° means no change in radiation direction, while
180° means that radiation is scattered backward. Much more light is scat-
tered in the forward direction (e< 90*) than in the backward direction (0
> 90"). We need to calculate phase functions to determine the amount of
light that is scattered into an observer's line of sight.
Phase functions p(X,9) for the plume and the background atmosphere
are determined from the tables in appendix B. These tables show phase
functions as a function of scattering angle [i.e., the angle between the
direct solar radiation and the line of sight as shown in figure 2(a),
chapter 2] for various particle size distributions and wavelengths X (0.4,
0.55, and 0.7 un). Figure 26 summarizes the phase functions at X = 0.55
wm. Note that p(e) is largest for small scattering angles (i.e., more
light is scattered in the forward direction).
To calculate average phase functions for the background atmosphere,
we must calculate the fraction of the total extinction coefficient result-
ing from:
> Light absorption by aerosols.
> Rayleigh light scatter due to air.
> Light scatter caused by submicron (accumulation mode)
aerosol.
> Light scatter caused by coarse aerosol.
First, we must calculate the background extinction coefficient from
the median visual range for the area:
bext(X= 0.55 mi) = 2 ^ (p_25)
112
-------
AIR
(RAYLEIGH
SCATTER)
PHASE FUNCTIONS AT A = 0.55
ARE SHOWN FOR PARTICLE SIZE DIS-
TRIBUTIONS WITH INDICATED MASS
MEDIAN DIAMETER (DG) AND GEO-
METRIC STANDARD DEVIATION (o = 2.0)
60 80 100 120 140
Scattering Angle e (degrees)
Figure 26. Phase functions for various particle size distributions.
113
-------
We assume that 5 percent of the background extinction coefficient is
caused by light absorption resulting from aerosols such as soot. Thus,
bscat(X= 0.55 un) = 0.95 b . (p-26)
The scattering coefficient caused by particles is determined by sub-
tracting the Rayleigh scattering coefficient:
b U = 0.55 wn) = bscat(X = 0.55) - bR(X * 0.55) , (p-27)
where bR(X = 0.55 un) = (11.62 x lO'V1) expl- Z^g0Q0°)» *n<) Z 5 eleva-
tion of site (m MSL). ^ ' .
Based on data of Whitby and Sverdrup (1978) and calculations of
Latimer et al. (1978), the fraction of bsp caused by coarse particles is
assumed to be 0.33.^ Thus, we have
bsp-submicron = °-67 bsp •
-------
sol modes can be determined from appendix B. We assume that the back-
ground submicron aerosol has a mass median diameter of 0.3 un and the
background coarse aerosol has a mass median diameter of 6 un. Both of
these aerosol modes are assumed to have a geometric standard deviation of
2.0. These size distributions are typical of those measured by Whitby and
Sverdrup (1978) in a variety of environments, including clean and average
rural and urban atmospheres. Phase .functions for these two size distribu-
tions are given in appendix B.
The Rayleigh scattering phase function (for air) is a function of the
scattering angle 0, but it is independent of wavelength X and can be
approximated quite well by the following relationship:
p(e) = 0.75 [1 + (cos 0)2] . (p-30)
At this point the analyst should fill in a table similar to table 5
for the scattering angles (9) shown or for those identified for specific
lines of sight, as portrayed schematically in figure 23. The scattering
coefficients at different wavelengths can be determined from the relation-
ship:
where values of n are given in table 4 for various particle size distribu-
tions and n = 4.1 for Rayleigh scatter.
The average background atmosphere phase functions are calculated for
each wavelength X and scattering angle 6 as follows:
]£? bsp(X) p(X,9)
P(X'e>|backgr6und ' y. ^ ' (p'32)
115
-------
TABLE 5. EXAMPLE TABLE SHOWING BACKGROUND ATMOSPHERE PHASE FUNCTIONS
AND SCATTERING COEFFICIENTS
Phase Function p(x,e)
Background Atmosphere - for Indicated e _
Scattering Component X(ym) b^nf1) 22* 45' 90* 135* 180*
Rayleigh Scattering 0.40
Due to air molecules ..JO.. 55
at site elevation
Mie Scattering .
Submicron aerosol 0.40
DG = 0.3 un 0.55
og = 2.0 0.70
Mie Scattering
Coarse aerosol 0.40
DG = 6 un 0.55
-------
where the summation is over Rayleigh, submicron, and coarse mode scatter-
ing categories.
The phase functions for the plume can be obtained from the tables in
appendix B corresponding to the size distribution of the primary particle
emissions. If this size distribution is not known, assume it has a 2.0 \an
mass median diameter (Schulz, Engdahl, and Frankenberg, 1975).
i
4.2.4 Calculating Plume Contrast and Contrast Reduction
With the procedure discussed thus far, the analyst can calculate the
magnitude of plume visual impact using equations (10) and (14) from
chapter 2. These equations are repeated here for convenience.
Plume Contrast
'plume
(pu)
plume
(pw)
- 1
background
exp(-bextrp>
Reduction in Sky/Terrain Contrast Caused by Plume
(P-33)
• -CQ exp(-bextr0)
1 -
where
(P-34)
, D
plume* ^background
= average phase functions for plume and back-
117
-------
ground atmosphere, respectively, p is a func-
tion of X and 0,
TNO? + Vrt + TS04 « - * • -
T = — & - - - 2. , T is a function of
plume sin o
X and a,
N°?
u . =1 -- =- , w is a function of X,
Plume Tplume
ox =0.95 (by assumption that 5 percent of total
estimation is due to light absorption by aero-
sol and that there is no background N0»
Dext = background extinction coefficient
(bext is a function of X),
rp = plume-observer distance
°-199x for stable plume
sin o
5Q km for 2-day-old plume during
sln a limited mixing conditions
rQ = object-observer distance,
CQ = intrinsic sky/terrain contrast of viewed object
(-0.7 to -0.9 for most terrain),
fQuj = fraction of total plume optical thickness
between observer and viewed object.
The analyst should calculate values of contrast for the following
permutations:
* It should be noted again that, for the stable plume case, there is no
sulfate ($04=), and for the two-day old plume during limited mixing
conditions, there is no N02.
118
-------
> Meteorological conditions; the Identified worst-case
stable and limited mixing conditions and the seasonal-
average limited mixing conditions.
> Class I areas: all potentially affected class I areas as
Identified by level-1 analysis.
> Line-of-sight azimuths: for all terrain features identi-
fied for each class I area observer at various rQ and a
and also at standard values of a.
> Wavelength: Certainly at X = 0.55 un. Calculations at
X - 0.40 and 0.70 un are recommended, especially for plume
contrast (Cp]ume) calculations.
If the absolute value of any plume contrast or contrast reduction
value (at any wavelength) is greater than 0.10, one cannot rule out the
possibility of adverse or significant visibility impairment. In such a
case, one may choose (1) to modify source emissions or siting, or (2) to
submit the results of the level-2 analysis or a more detailed (level-3)
analysis to the appropriate government official for review and case-
specific determination of the significance or adversity of the visual
impact in the potentially affected class I area(s).
4.3 USE OF REFERENCE TABLES FOR N02 IMPACTS
As an adjunct to the hand calculations or as a replacement for some
of the Cplume calculations, one may wish to use the reference tables in
appendix C. These tables are appropriate only for emissions sources such
as power plants, boilers, and other combustion sources that emit NOX, from
which the principal plume colorant is N02. One should not use these
tables for a source with NOX mass emissions rates less than 5 times the
particulate emissions rate. These tables provide values of the following
parameters that describe the contrast of a plume against the horizon sky:
> Blue-red ratio R:
' 1 + CDlume(X = 0.4 un)
l + Cplume(X=0.7 i")
119
-------
> Plume contrast Cpiume (X = 0.55
> Plume perceptibility parameter AE(L*a*b*).
To use these tables, calculate Tpart (for the worst-case stable plume
condition only) on the basis of the procedures given earlier in this
chapter, using the given particle mass emissions rate and size distribu-
tion, oz, u, and a. Compute the approximate visual range:
rv = rvO (1 * Vt/3'912)
Calculate the line-of-sight integral of plume N02» in units of yg/m2,
from the following formula:
(1 4Q «
[N0?] dr = i— " "••'-•'z-' , (p.
plume Sln °
where
x £ downwind distance in km,
[N02] * N02 concentration as calculated using procedures
in the previous section,
a = angle between the plume centerline and the line
of sight.
The analyst should use the appropriate table in appendix C for the
given (reduced) visual range, N02 line-of-sight integral, and plume-
observer distance rp and determine the visual impact parameters from this
table. If the blue-red ratio is less than 0.90, 1f plume contrast is less
than -0.10, or if AE(l*a*b*} is greater than 4.0, the probability of
adverse or significant plume discoloration cannot be ruled out.
120
-------
4.4 USE OF REFERENCE FIGURES FOR POWER PLANTS
If the emissions source is a power plant, one of the figures in
appendix D may apply to the case being evaluated. Note that the percen-
tage visual range reduction is for a line of sight perpendicular to the
plume center!ine. The reduction in sky/terrain contrast at X = 0.55 vm
can be calculated from this percentage visual range reduction as follows:
AC = -C. exp/-3.912 r /r n\ 1 - exp (- i^i f . _5!— \
r 0 I o vO) \ 100 obj sin o/
L 7J (P-37)
where
f0tjj = fraction of plume between observer and object,
AV = percentage reduction in visual range or line of sight perpen-
dicular to plume centerline
\
= -(r~M " 100*'
Cg, r0, rv0, and a are as defined previously.
4.5 USE OF THE COMPUTER MODEL
Probably the easiest and most accurate method for determining levels
of impact is to use the plume visibility computer model (PLUVUE)
initialized to the given worst-case conditions and geometry identified
using the procedures presented in sections 4.1 and 4.2. The reader should
refer to the separate document entitled, "User's Manual for the Plume
Visibility Model (PLUVUE)", EPA-450/4-80-032, before using this model.
4.6 EXAMPLE CALCULATIONS
The reader may refer to appendix E for two sets of example calcula-
tions using the level-1 and level-2 analysis procedures. These examples
121
-------
are hypothetical power and cement plants.
4.7 SUMMARY OF LEVEL-1 AND LEVEL-2 PROCEDURES
Figures 27 and 28 (a through f) present a series of schematic, logic,
flow diagrams that summarize the major steps of the level-1 and level-2
screening procedures. Once the reader has become familiar with the actual
steps necessary to carry out analyses through level-2, these flowcharts
can be used as a checklist.
Several conventions in the flowcharts should facilitate their use.
The specific section numbers in the workbook describing the individual
steps are identified within each flowchart. The reader may, therefore,
use the flowcharts to identify the location of various equations and pro-
cedures presented in the text. A list of the variables for which
numerical values have been determined in that step is presented at the end
of each flowchart. This list can be used to locate the calculations lead-
ing to each variable. In general, aside from the oval start-and-stop
blocks in the flowcharts, three different shapes of blocks are used.
Rectangular blocks indicate a straightforward procedure or calculation;
diamond-shaped blocks indicate decision points with regard to whether
further analysis is needed; and computer-card-shaped blocks (with clipped
corners) indicate a data collection or interpretation task.
The presentation of a hand calculation procedure (section 4.2) is not
intended to imply that some level of automation is not appropriate. Those
users with access to a computer or programmable calculator can benefit
from setting up segmented programs for the steps presented in the flow-
charts, since the complexity of the calculations contributes to the like-
lihood of undetected computational errors in results. These flowcharts
can be used as the preliminary basis for developing the necessary computer
language codes or calculator step sequences, and the accuracy of the
results from such programs can be tested using the numerical values con-
tained in the examples in the text and in appendix E.
122
-------
c
START
DETERMINE DISTANCE x
FROM EMISSIONS SOURCE
TO CLASS I AREA
| LOOK UP VERTICAL DIF-
FUSION COEFFICIENT o_
CALCULATE DISPER-
SION PARAMETER p
DETERMINE PARTICULATE,
NOX, AND S02 EMISSION
RATES Q
CALCULATE ESTIMATES OF
OPTICAL THICKNESS T
CALCULATE CONTRAST
PARAMETERS C
DETER-
INE WHETHER C
VALUES INDICATE THE
NEED FOR LEVEL-2
ANALYSIS
PERFORM
LEVEL-2 ANALYSIS
ALL IC.I < 0.1
Figure 27. Logic flow diagram for level-1 analysis (see section 3.2)
123
-------
c
START
DETERMINE GEOGRAPHY IN THE VICINITY
OF THE SOURCE AND CLASS I AREAS.
IDENTIFY KEY VISTAS.
i
DETERMINE STACK PARAMETERS
RELATED TO PLUME BUOYANCY
AND VELOCITY EFFECTS
CALCULATE PLUME RISE AND
LOCATE POSSIBLE TRAJECTORIES
FROM SOURCE TO VISTAS
i
DETERMINE TRANSPORT DISTANCES, ELE-
VATIONS ALONG LINES OF SIGHT, VIEW-
ING DISTANCES, ETC., FOR KEY VISTAS
C
i
STOP
3
Variables known at the end of Step 1
.*, Z, Z
block'
From Level 1.
Different values can be determined for
different trajectories and vistas.
(a) Step 1: Description of the area and possible trajectories
Figure 28. Logic flow diagram for level-2 analysis (see section 4.1.1)
124
-------
f START J
DEVELOP JOINT FREQUENCY DISTRIBUTIONS OF
STABILITY/ WIND SPEED, AND WIND DIRECTION
TABULATE THE FREQUENCY OF METEOROLOGICAL
CONDITIONS IN ORDER OF INCREASING DISPER-
SION FOR WIND DIRECTIONS ASSOCIATED
WITH POTENTIAL IMPACTS
IDENTIFY THE DISPERSION CONDITION
(oz u) PARAMETER THAT CHARACTERIZES
THE 1-PERCENTILE (~4 DAYS/YEAR)
WORST-CASE EVENT
r STOP j
Variables known at the end of step 2: o.
u
* This step is not necessary if the Ieve 1-1
analysis shows C1 and C2 between -0.1 and +0.1.
t Values can be determined for different trajec-
tories and vistas.
(b) Step 2: Specification of worst-case stable transport
meteorological conditions (section 4.1.2.1)
Figure 28 (Continued)
125
-------
c
START
DEVELOP JOINT DISTRIBUTION DATA
FOR MIXING DEPTH, WIND SPEED, AND
PERSISTENCE OF CONDITIONS
IDENTIFY CLASS I AREAS
BY DIRECTION AND
DISTANCE FROM SOURCE
CALCULATE THE PROBABILITY OF
CLASS I AREAS BEING IMPACTED
UNDER DIFFERENT WIND SPEED
AND PERSISTENCE CONDITIONS
TABULATE THE FREQUENCY OF
METEOROLOGICAL CONDITIONS IN
ORDER OF INCREASING DISPERSION
FOR PERSISTENCE CONDITIONS
RESULTING IN POTENTIAL IMPACTS
ON CLASS I AREAS
®
IDENTIFY THE LIMITED MIXING
CONDITIONS (uHm) THAT CHARAC-
TERIZE THE 1-PERCENTILE (~4
DAYS/YEAR) WORST-CASE EVENT)
C
I
STOP
Values known at the end of step 3:
* This step is necessary only if the level-1 analysis shows C~ to be greater
than 0.1. 3
t Although a single dispersion parameter u-Hm should be determined, multiple
pairs of values can be determined at this step. For example, (2 m/s, 1000 m,
and 4 m/s, 500 m) give the same value for u«Hm of 2000 m2/s.
§ Because of the dramatic variability in the type and level of detail of
available meteorological data, this flowchart indicates only the general
intent of steps necessary to specify the limiting diffusion parameter u-Hrn.
(c) Step 3: Specification of worst-case meteorological conditions
for general haze5 (see section 4.1.2.2)
Figure 28 (Continued)
126
-------
c
START
| DETERMINE MEDIAN OZONE CONCENTRATIONS
I THAT CHARACTERIZE SEASONS OF CONCERN
I
DETERMINE MEDIAN BACKGROUND
VISUAL RANGE(S) THAT CHARACTER-
IZE THE SEASONS OF CONCERN
C STOP J
Values known at the end of step A: [0^],
(d) Step 4: Background atmosphere description
(sections 4.1.3 and 4.1.4)
127
-------
c
START
DETERMINE PLUME CENTERLINE-OBSERVER
RELATIONSHIPS AND TIME AND DAY
FOR SPECIFIC SCENARIOS
DETERMINE AZIMUTHS/ as, AND SCATTER-
ING ANGLES (0) FOR LINES OF SIGHT
1
DETERMINE OBSERVER-OBJECT DISTANCES
i
( STOP J
Values known at the end of step 5 :
a, 0, r , r
' ' o' p
* There will be a number of values for each of
the lines of sight on data and times considered.
(e)' Step 5: Determination of plume-observer geometries and
specification of scenarios (section 4.2.1)
128
-------
f START J
DETERMINE SIZE DISTRIBUTION
PARAMETERS FOR PRIMARY PARTICU-
LATE EMISSIONS
-------
CALCULATE BACKGROUND ATMOSPHERIC
SCATTERING CHARACTERISTICS, bext,
bscat/ bsp/ and bR FOR APPROPRIATE
WAVELENGTHS AND SIZE RANGES
DETERMINE PHASE FUNCTION VALUES, pU,9),
FOR SCATTERING ANGLES OF CONCERN FOR
BACKGROUND, PLUME, AND GENERAL HAZE
I
CALCULATE AVERAGE PHASE FUNCTION
VALUES FOR BACKGROUND (P(A,0)>
CALCULATE PLUME CONTRAST, C
plume
CALCULATE REDUCTION IN SKY-
TERRAIN CONTRAST, AC
INTER-
PRET RESULTS
OF LEVEL-2 ANALY-
SIS FOR ALL
SCENARIOS.
-0.1 < CpLume < 0.1
and AC < 0.1
r
STOP
(f) (Concluded)
Figure 28 (Concluded)
cplumel ^
or
1
MORE ANALY
SIS NEEDED
130
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5 SUGGESTIONS FOR DETAILED VISIBILITY IMPACT ANALYSES (LEVEL-3)
Jf the level-1 and -2 visibility screening analyses indicate the pos-
sibility of adverse or significant visibility impairment, one may wish to
undertake a more detailed analysis (level-3). Even if a source passes the
level-1 and -2 screening tests, it may be advisable to analyze potential
Impacts 1n greater detail.
More detailed visibility analyses may be needed in the following cir-
cumstances:
> When level-1 and -2 screening analyses indicate the possi-
bility of adverse or significant visibility impairment.
> When the potential costs and delays incurred in emissions
source siting,-emissions control design, and regulatory
approvals indicate that more detailed studies would be
beneficial, regardless of the outcome of the level-1 and
-2 screening tests.
> If greater accuracy and definition are necessary, for
example, to define the frequency of occurrence and the
time of year of worst-case impacts.
> If emissions are of a special nature, such as reactive
hydrocarbons. In such cases one should use models that
account for photochemistry (e.g., a reactive plume model
with a complete photochemical mechanism).
> When the appearance of the visual impact is a concern
(that 1s, when considering what the worst-case discolored
prlume or haze will look like).
> When the effect of visibility impairment on perceived
scenic beauty in a class I area requires quantification,
as when a cost-benefit study Is performed.
131
-------
> When area topography is complex, so that the assumptions
made in the level-1 and -2 screening analyses are no
longer appropriate, as when plumes are blocked, channeled,
or trapped by terrain features.
> When an emissions source that is being analyzed, or is
similar to the one being analyzed, is currently operating.
Under these circumstances, it would be desirable,
especially if level-1 and level-2 tests indicate a poten-
tially adverse or significant impairment, to supplement
screening analyses with detailed impact analyses and with
intensive and long-term monitoring of meteorological and
ambient conditions; plume transport, diffusion, and chem-
istry; and visual impacts in the potentially affected
class 1 areas.
> When the concern is with the cumulative impacts of several
emissions sources within a region.
It is not the purpose of this chapter to provide step-by-step
instructions for carrying out these more detailed analyses. Each separate
analysis will vary with the specific circumstances. Instead, we briefly
outline some important elements in such detailed analyses that the analyst
may wish to consider. Indeed, further visibility model development may be
needed for some problems.
5.1 FREQUENCY OF OCCURRENCE OF IMPACT
As discussed in chapter 2, the frequency of occurrence of visibility
impairment is as critical to the assessment of adversity or significance
of impact as is the magnitude of visibility impairment. We can assess the
frequency of impact occurrence by applying a computer model to all poten-
tial combinations of the following factors:
132
-------
> Emission rates.
> Wind speed.
> Wind direction.
> Stability.
> Mixing depth.
> Plume dispersion, given a specific meteorological condi-
tion.
> Background ozone concentration.
> Background visual range.
> Precipitation.
One might require 100 or more model runs to characterize adequately the
magnitude and frequency of impact occurrence in some situations. Impact
can then be summarized in figures or graphs, as shown in figures 29, 30,
and 31 and tables 6 and 7- Note that these examples were stratified by
season to illustrate the seasonal dependence of impact and the fact that
for this example the maximum frequency of impact occurrence is predicted
in the winter season when class I area visitor use may be minimal.
5.2 APPEARANCE OF IMPACTS
A further specification of the appearance of visual impacts may be
necessary to supplement estimates of magnitude and frequency of occur-
rence. The adversity or significance of an impact is dependent on the
size of the area affected by a plume, as well as by the magnitude of dis-
coloration or contrast reduction. A plume viewed from a distant location
has a smaller visual impact than it would if viewed from a nearby loca-
tion, even if the magnitude of discoloration is the same in both
instances, because in the former situation, the plume affects fewer lines
of sight (i.e., appears smaller). A 200-m-thick plume will subtend an
angle of 1.2' when the observer is 10 km away, 0.5° (which is the angle
subtended by the moon) when the observer 1s 25 km away, and 0.1" when the
observer is 100 km .away from the plume centerline.
133
-------
days
(a) Winter
days
(b) Spring
15
days
(c) Sunnier
20
Figure 29.
* days
(d) Autumn
n^lt?K?f Jred1cte? frec»uency °f occurrence of plume discoloration
perceptible from a class I area: number of mornihgs in the
season with an impact greater than the indicated value.
134
-------
3
M
510
•UNITS 1-4
•UNITS 1 AND 2
10
IS
20
days
(a) Winter
25
251
20
UNITS 1-4
UNITS 1 AND 2
10
15
20
25
days
(b) Spring
UNITS 1-4
UNITS 1 AND 2
10
15
20
days •
(c) Summer
25.
25
UNITS 1-4
UNITS 1 AND 2
15
20
25
days
(d) Autumn
Figure 30. Examples of predicted frequency of occurrence of haze (visual
range reduction) in a class I area: number of Afternoons in
the designated season with an impact greater than the
indicated value.
135
-------
•SMMCO flEMIMC
i-CUM SKT. 2-min MJICT.
S-CRRT MJECT. 4-Bl.ftCK OOJICT.
70.0
S 60.0
gso.o
« «0.0
jn
> so.o
•>
§20.0
" 10.0
0.0
1.3
1.2
= 1.1
£1.0
gO.9
J"
^0.7
0.6
0.5
0.4
0.2
0.1
_-0.0
*l
|*0.1
8 -0.2
I*.
c-o.«
-0.5
-o.e
40.0
35.0
30.0
En.o
u
0 1S.O
10.0
s.o
0.0
«s
90
I3S
M1HUTH
180
.. i
225
270
(a) 1 m/s wind speed, stable condition, 348.8 degree wind direction
Figure 31. Examples of calculated plume visibility impairment dependent
on wind direction, azimuth of line of sight, and
viewing background.
136
-------
MSWCO flCMINC MCKCMtMD:
I-CLEM SKT. t-UHIU HJCCT.
»-6MT MJtCT. 4-H.OCK
8.1
.2
«5
135 180 22S
MZ1MUTH MNCLEIOECRtESI
270
ssa
(b) 1 m/s wind speed, stable condition, 11.3 degree wind direction
Figure 31 (Continued)
137
-------
•MMCO VtCNIItt MCRGMtflffi:
I-CLEM SKY. 2-tWltt MJCCT
»-GJ
-------
TABLE 6. EXAMPLE SUMMARY OF THE FREQUENCY OF OCCURRENCE OF POWER PLANT
PLUME DISCOLORATION PERCEPTIBLE FROM A CLASS I AREA1
CO
VO
Number of Mornings with £(L*a*b) Greater than Indicated Value
2.5
10
Season
Winter
Spring
Summer
Fall
Annual total
Units
1 and 2
4
1
2
3
10
Units
1 through 4
6
2
3
5
16
Units
1 and 2
2
< 1
1
1
4
Units
1 through 4
3
1
1
2
7
Units
1 and 2
< 1
0
0
< 1
1
Units
1 through 4
1
0
0
< 1
< 2
-------
TABLE 7. EXAMPLE SUMMARY OF FREQUENCY OF OCCURRENCE OF INCREASED HAZE (VISUAL
RANGE REDUCTION) IN A CLASS I AREA DUE TO POWER PLANT EMISSIONS
Number of Davs with Visual Ranqe Reduction
Greater than Indicated Value
Season
Winter
Spring
Summer
Fall
Annual total
Units
1 and 2
9
3
4
5
21
5%
Units
1 through 4
10
3
4
5
22
Units
1 and 2
3
1
0
2
6
10%
Units
1 through 4
5
2
1
3
11
Units
1 and 2
0
0
0
0
< 1
15%
Units
1 through 4
1
< 1
0
1
2
-------
Also, the appearances of the plume will change depending on the wind
direction and the viewing background distance and coloration. Thus, one
has to know the viewing background and the vertical and horizontal
(azimuthal) extent of the plume to characterize the visual impact com-
pletely.
The appearance of plume discoloration and contrast reduction can be
quantified using calculations of the magnitude of impact as a function of
vertical and horizontal orientation of the line of sight, or by specifying
the angle subtended by a plume. Alternatively, one can display impact
using
> Black-and-white plume-terrain perspectives (see example in
figure 32).
> Color graphic displays, such as those developed by the Los
Alamos Scientific Laboratory (Williams, Treiman, and
Wecksung, 1980).
> Color photographs of plumes or haze similar to the condi-
tions being analyzed.
5.3 IMPACTS ON SCENIC BEAUTY
There is some recent evidence (Latimer, Daniel, and Hogo, 1980) that
the scenic beauty of some areas may not be adversely affected by reduc-
tions in visual range, though the scenic beauty of other areas may be very
sensitive to visual range. There have been no studies to determine the
scenic beauty sensitivities of class I areas to plume visibility impair-
ment (i.e., discoloration and contrast reduction).
141
-------
ro
Figure 32. Example of black and white plume-terrain perspective.
-------
In certain detailed visibility impact assessments, it may be
desirable to quantify the sensitivity of potentially affected areas. For
example, days of visual impact of a given magnitude might be translated
into days of a given decrease in class I area scenic beauty (as perceived
by an observer). This would be an essential first step in establishing
the aesthetic benefits of a given emissions control action.
5.4 IMPACTS OF EXISTING EMISSIONS SOURCES
Although the primary purpose of visibility computer modeling and the
screening analysts techniques presented in this workbook is the prediction
v -
of future impacts of proposed new sources, these analytic tools can also
Be used to evaluate the impact of existing sources. However, because
these techniques are not required to be routinely exercised in any
regulatory program applicable to either new or existing sources, mon-
itoring techniques, esoecially visual observations (either ground based
or with aircraft), are likely to be the first step in identifying the
origin of visibility impairment caused by a single source or small group
of sources.
EPA has published the document "Interim Guidance for Visibility
Monitoring," EPA-450/2-80-Q82, which contains technical considerations
involving the design of visibility monitoring programs, selection of
instrumentation, quality assurance and data processing. Instrumental
monitoring methods for visibility are not yet routinely required in
regulatory programs for visibility protection but the guidance does
Provide substantial information regarding available visibility monitoring
presently i.n use'. It is recommended that a minimum of one full
143
-------
year of monitoring be conducted for visibility impact analyses of major
point sources.
In addition to this long-term (one year or longer) measurement/
analysis program, it may be desirable to design and implement several
short-term, intensive measurement programs to compare measurements and
model predictions of plume transport, diffusion, chemistry, aerosol forma-
tion, and the resulting optical effects.
5.5 REGIONAL IMPACTS
In many cases, the visibility impairment caused by a single emission
source may be small compared to the cumulative impacts of many natural and
man-made sources in a region. However, the visibility impairment of that
single source may contribute to a significant regional haze.
It is beyond the scope of the first phase of visibility regulations
and of this workbook to address such cumulative, regional impacts.
Regional visibility models and measurement/analysis programs will be
required to assess the extent of existing regional visibility impairment,
to determine the relative contributions of various emissions sources to
that impairment, and to design and implement effective emissions control
144
-------
on a regional scale (if possible) to restore and protect class I area
visibility.
145
-------
APPENDIX A
CHARACTERIZING GENERAL HAZE
One of three parameters is customarily used to characterize general
atmospheric haze:
> Visual range
> Extinction coefficient
> Sky/terrain contrast.
Each of these is an equally valid means of quantifying atmospheric
haze. Since the eye/brain system perceives the environment through color
and brightness contrasts in various objects such as landscape features,
the sky/terrain contrast is the most fundamental of these three parameters
in terms of visual perception. However, contrast may not be the most
appropriate means of describing haze, because one can have a large number
of contrast values for different landscape features if such features are
at various distances from the observer and have different intrinsic
contrasts. Thus, in many situations extinction coefficient and visual
t range are simpler and more useful measures of atmospheric haze than is
contrast. The relationships among these physical measures of atmospheric
haze are discussed in more detail in the following subsections.
A.I WAVELENGTH DEPENDENCE
It is important to note that each of these three parameters depends
on the wavelength of light (x) to be considered. Since the light-
scattering properties of the atmosphere are a function of wavelength, each
of these three atmospheric haze parameters is likewise a function of wave-
147
-------
length. For example, Rayleigh scattering by air molecules is proportional
to X-4, and Mie scattering for a typical aerosol is proportional to X~n,
where generally 0 < n < 2. The spectral reflectance of a landscape
feature will also be a function of wavelength if the landscape feature is
not white, gray, or black.
Because of this wavelength dependence, we must be specific when we
define visual range, extinction coefficient, or contrast. Many optical
instruments and the human eye respond to a broad wavelength band; others
are narrow-band instruments. Indeed, some of the discrepancies among
various measurements of atmospheric haze (in which such techniques as
nephelometry, te.lephotometry, photographic photometry, and human
observation are used) are due to the different spectral sensitivities of
each instrument.
Throughout this discussion we will assume that contrast, visual
range, and extinction coefficient are defined in equivalent ways with
respect to wavelength. For example, we can define these parameters for a
narrow wavelength band at 0.55 vm, the center of the visible spectrum, or
a broader band with some characteristic wavelength. This discussion does
not depend on which wavelength band is considered, but the three
parameters must be defined for similar spectral bands.
A.2 THE CONTRAST FORMULA
For a homogeneous atmosphere, contrast and extinction coefficient are
mathematically related by the Lambert-Beer law for contrast, as follows:
Cr/CQ = e" extr° , (A-l)
where CQ is the intrinsic contrast of a landscape feature against the sky
(as observed near the feature), Cr is the apparent contrast of the land-
scape feature observed from a distance rQ, and bext is the extinction
coefficient of the atmosphere through which the terrain is observed.
148
-------
Using Middleton's (1952) definition of visual range, we can also
relate visual range to contrast and extinction coefficient. Visual range
is defined as the distance rv such that
Cr/CQ = 0.02 = eex v . (A-2)
Note that by solving for ry we have the well-known Koschmieder rela-
tionship,
r _ *n(0.02) .3.912 lh ,.
v B~~ F~T~ ' ( *
ext ext
These relationships can be extended to nonhomogeneous atmospheres if
we define an appropriate average extinction coefficient over the line of
sight of interest.
A. 3 QUANTIFYING INCREASES IN ATMOSPHERIC HAZE
When the impact of a proposed source or combination of sources on
atmospheric haze is of concern, the relevant question is: what is the
resulting change in atmospheric haze conditions compared with that which
would occur otherwise? For example, one might be concerned with the
increase in haze that results from certain emissions on a particular day,
on the worst day in a year, or on an average day in a year. Alterna-
tively, one's concern might be the shift in the seasonal or annual fre-
quency distributions of haze conditions.
We can quantify increased atmospheric haze by one of four parameters:
> Increased extinction coefficient (Abext) or fractional
increase relative to a given background (&ext/bexto)-
> Decreased visual range (-Ary) or fractional decrease in
visual range relative to a given background (-Arv/rv0)-
> Decreased sky/terrain contrast (-ACr) or fractional
decrease in contrast relative to the contrast that would
occur for a given background (-ACr/Cr0).
149
-------
> Plume optical thickness (TpiulT,e), the integral of extra
extinction (Aext) along the line of sight through the
plume.
The remainder of this discussion describes these four parameters and the
relationships among them.
There are two general classifications of spatial distributions of
increased extinction (see figure A-l):
> Nonuniform distributions over a portion of the line of
sight (e.g., a plume).
> Uniform increase over the entire line of sight (e.g.,
regional haze or situations in which the plume width is
large compared to the visual range or to the line of
sight).
The impact of a plume is best described by the plume optical thick-
ness (Tp-jume), whereas the regional impact is better described by extra
extinction (Abext).
A. 3.1 Plume Impacts
Plume optical thickness is defined as the integral of the extinction
coefficient over the line of sight:
This optical depth can be converted to an average extinction coefficient
over some line of sight at distance R:
*ext = Tplume/R •
The distance R may be the distance between the observer and a particular
landscape feature (r0) or the visual range distance (ry), depending on the
150
-------
Plume of extra extinction
Landscape feature
Observe
Observer-terrain distance r
(a) Nonuniform distribution of extra extinction (plume impacts):
Observe
Homogeneous mixed layer of extra
extinction (or a dispersed plume)
landscape feature
at distance r^
(b) Uniform distribution of extra extinction (regional haze or dispersed plumes)
Figure A-l. Two types of spatial distributions of extra extinction.
-------
problem being addressed. For example, if one is concerned about the con-
trast loss in a landscape feature at a given distance from an observer, it
is appropriate to use the distance to that feature as the value for R.
However, if several landscape features at different distances are
involved, or if one does not know the distance to a landscape feature, it
is appropriate to use the visual range distance rv as the value of R.
If we do the latter, we obtain a rather simple and elegant formula
for the visual range reduction caused by a plume. The total average
extinction coefficient of the background atmosphere and the plume together
is
\
u u _L plume /. e\
bext = bextO + -17- • (A'6)
where bexto is the extinction coefficient of the background atmosphere
with visual range rv0, Tplume is the plume optical thickness, and rv is
the reduced visual range as a result of plume impact.
The reduced visual range caused by plume material can be determined
by substituting equation (A-6) into the Koschmieder relationship, equation
(A-3), and solving for ry. The result is
rv = rvO U ' Tplume/3'912) •
The fractional reduction in visual range is simply
3.912
Note that equations (A-7) and (A-8) are not valid for cases in which
the plume is opaque (e.g., one cannot see beyond the plume) or is
significantly discolored. For such cases a more detailed visibility model
or the formulas provided in the text should be employed.
Note that the fractional reduction in visual range for this plume
situation is independent of the background visual range (rv0).
152
-------
A.3.2 Regional Haze Impacts
For the second case, in which there is a uniform increase in extinc-
tion coefficient (4bext)» the fractional decrease in visual range is not
independent of the background visual range:
r =
3.912
3.912
*
ext
(A-9)
rvO - rv
rvO
1 -
3.912
-1
(A-10)
1 -
Jext
3extO
-1
(A-ll)
A.4 THE EFFECT OF INCREASED HAZE ON THE CONTRAST OF LANDSCAPE FEATURES
The sensitivity to increased haze of the sky/terrain contrast of a
landscape feature observed from a distance r0 can be evaluated by
differentiating equation (A-l):
(A-12)
The observer-terrain distance rQ at which the greatest change in con-
trast per unit change in extinction coefficient occurs can be determined
by differentiating equation (A-12) again with respect to r, setting this
derivative to zero, and solving for r. This distance is found to be
°'26 r
vO
(A-13)
153
-------
On the other hand, the greatest fractional change in contrast per unit
change in extinction coefficient occurs with the most distant visible
landscape features. This can be shown by rearranging equation (12):
1 -^E-.-r . (A-
r ext
Thus, depending on whether the human observer detects changes in haze
conditions as a result of fractional or absolute changes in contrast,
landscape features at distances of the full visual range or about one-
fourth the visual range will be the most sensitive perceptual cues,
respectively.
The change in contrast (ACr) of a landscape feature resulting from a
given change in extinction coefficient (Abext) can be evaluated by
integrating equation (A-12):
acr = -C
J • (A-15)
• ^ mJ
If the change in extinction coefficient (*bext) is due to a plume
between the observer and the landscape feature, then the change in con-
trast can be calculated as follows, assuming that the plume does not sig-
nificantly discolor the horizon sky:
*r = 'Cr L1 - e"Tplume]
154
-------
With the following transformation of variables, we can relate the
change in sky/terrain contrast to extinction coefficient, plume optical
thickness, and visual range reduction in a more lucid manner:
f = ratio of observer-terrain distance r to background visual range
* ro/rvo , (A-17)
f. s fractional increase in extinction coefficient
b
(A-18)
'extO
f, = fractional decrease in visual range
V (
. rvO - rv
rvO
With these transformations we can write the equations for the rela-
tionships between contrast change and other visibility parameters as
follows:
Extra extinction: &r = -Cr I 1 - exp(-3.912 frfb)J , (A-20)
Visual range reduction: &r = -Cr
1 - exp -3.
(A-21)
Plume optical thickness: &r = -Cf [ 1 - exp(-Tpiume)J
155
-------
The value of Cr is a function of the intrinsic contrast (C0) of the
landscape feature and the distance to the feature relative to the back-
ground visual range (fr):
Cr = CQexp(-3.912 fj . (A-23)
The change in sky terrain contrast (tCr) as a function of increased
extinction, reduced visual range, and plume optical thickness is plotted
in figures A-2, A-3, and A-4, respectively. Sky/terrain intrinsic con-
trast (C0) was assumed to be -1.0, which is appropriate for a black
object. The effect of observer-terrain distance on these relationships is
shown by plotting curves for r/rVQ = 0.1, 0.26, 0.5, and 0.75. The
maximum decrease in contrast for a given increase in extinction or
decrease in visual range occurs for landscape features at 26 percent of
the visual range, as we noted earlier, while the maximum contrast decrease
due to a plume occurs for the closest landscape features.
A.5 SUMMARY
The relationships among the parameters used to characterize increased
atmospheric haze are summarized in table A-l.
156
-------
0.14
en
0
0.1 1.0
Fractional Increase in Extinction Coefficient (Ab
10.0
ext/bextD
Figure A-2. Change in sky/terrain contrast as a function of fractional increase in
extinction coefficient for various observer-terrain distances.
-------
o
o
I
Q)
CO
to
u
-------
0.14
01
VO
0.1 0.2 0.3
Plume Optical Thickness (T
0.4
0.5
pi ume'
Figure A-4. Change in sky/terrain contrast as a function of plume optical
thickness for various observer-terrain distances
-------
TABLE A-l. SUMMARY OF RELATIONSHIPS AMONG PARAMETERS USED FOR QUANTIFYING INCREASED ATMOSPHERIC
To Convert From
To:
Tplume
fb
fv
fc 1
*0l time fb fv fc
fb R bexto 3.912 fv - tn (1 - fc)
Tplume v tn u - TCJ
R DextO l - fv 3-912 fr
Tplume fb - tn (1 - fc)
3.912 1 + f. 3.912 T - tn U - TC)
[ 3 912 f / fv \1
^ pi ume « r » • r b " r \ 1 - T. /
r \ v /
Nomenclature
9»
O
/plume
bext dr
f- = ration of observer terrain distance rn to background visual range rvr»
Abext
f. ~ f>* apt- inn A! inproaco in ovt inrtinn crtof^lr'ionl* a
IK = 1 1 QI» b i Una l i iicf c
-------
APPENDIX B
PHASE FUNCTIONS
Data for the aerosol phase function [p(X,e)] are provided in this
appendix as a function of these factors:
> Aerosol size distribution with different mass median
diameters (DG), all with a geometric standard deviation og
of 2.0.
> Wavelength X = 0.40, 0.55, and 0.70 vm.
> Scattering angle e (Oe < 0 < 180°).
161
-------
DG
X
0.1 ym
0.4 ym
e
6,0
M
10,0
12,0
14,0
16,0
18,0
2-0,0
22,0
24,0
26,0
28,0
30,0
32,0
34,0
36,0
38,0
40,0
<«2,0
uu.o
46,0
48,0
50,0
52,0
54,0
56,0
58,0
60,0
62,0
64,0
66,0
6«,0
70,0
72,0
74,0
76,0
78,0
80,0
82,0
84,0
86,0
86,0
90,0
0
«.flt55E-01
5.5565E+00
5.5052EtOO
5.42l9EfOO
5.309
-------
DG = 0.1
X = 0.55
0_
0,0
2.0
4,0
S'°
8,0
10,0
12,0
14.0
16,0
18,0
20,0
22,0
24,0
26,0
28,0
30,0
32,0
34,0
36,0
38,0
40,0
42,0
44,0
46,0
48,0
50,0
52,0
54,0
56^
58,0
60,0
62,0
64,0
66,0
68,0
70,0
72,0
7«,0
76,o
80,0
82,0
84,0
86,0
88,0
,*,e;
fl«fl9o5ftoo
4.4799E+00
4.4(|63EtOO
+0
4.3263E+00
4.2389EtOO
4.1367E+00
4.0217E+00
8963EtOO
,7627EtOO
,6228£*00
,4787EtOO
.3319£tOO
I UT V V
tf,cu«3EtOO
2.0804E+00
'.9&17E+00
.8482E+00
,7401E+00
,6373EtOO
.5398E+00
.4476E+00
.3606E+00
•»* a t~e . *n
;20l6EtOO
.1294E+00
§Obl9EfOO
9.9882E.01
9t4009E.Ql
8*3485E»01
7.8799E.01
7.447JE.01
7.0490E-01
6,6833E«01
6,3485£.01
6t0429£.01
5.7650E.01
5.5130E-01
5.2857E-01
94,0
9b,0
98,0
100,0
102.0
104.0
106,0
108,0
110.0
112.0
114.0
116.0
118.0
120.0
122,0
124.0
126.0
126.0
130.0
132,0
134.0
136.0
138.0
140,0
142.0
144.0
146.0
148.0
150.0
152,0
J54.0
156.0
158,0
160.0
162.0
164,0
166.0
16P.O
170.0
172.0
174.0
176.0
178.0
180.0
P(A.e)
5.06UE-01
4,896AE*01
4.7367E.01
4.4689E.01
4,3609E.Q1
4.2685E.01
4.1908E-01
4.1267E.O!
4.0357E.01
4,0070E»01
3,98B«E«01
3.979JE-01
3.9784E.OI
3.9BS4E.01
4,0202E*01
4,0466£»01
4,078lE«Ot
,
4,1544E«01
4.1981E-01
4.2447E.01
4.2938E.OI
4.3447E-01
4.3970E.01
4,4501E*01
4.5035E-01
4.5568E-01
4.6095E-01
4.6612E.01
fl.7H7E.Ol
4,7*08E»Ol
4.6083E.01
,
4,8975E«01
4.9388E-01
4,9772E.01
5,0120E*01
5,0424E*01
5.0675E-01
5,0862E«01
5,0979E-01
5,i018E-01
163
-------
DG
x
0.1 ym
0.7 ym
e_
0.0
2,0
4.0
6,0
8,0
10,0
12,0
14,0
16,0
18.0
20,0
22,0
24.0
26,0
28.0
30,0
32,0
3^,0
36,0
38,0
40,0
«2,0
50,0
S2,0
5«,0
S6,0
58.0
60,0
62,0
64.0
66,0
68 0
70,0
72,0
74,0
76,0
78,0
80,0
82,0
84,0
86,0
88,0
90,0
P(x.e)
3,8l7dE*oO
3.6103E+00
3.78B6E+00
3.7529E*00
3,7oJ9£tOO
3.6427E+00
3.5703E+00
3.4881E+00
3.3974E+00
3.2995EtOO
3.1959E+OU
3.0878E*00
2.9764EtOO
2.8b29EfOO
2,6330E*00
2.5l8
-------
DG = 0.2 pm
A = 0.4 ym
e
2,0
4,0
i'°
8.0
10,0
12,0
14.0
16,0
18,0
2t>,0
22,0
2^,0
26,0
26,0
10,0
32. n
34,0
36,0
38,o
40,0
42.0
44.0
«6,0
ae.o
50,0
S2.0
54.0
56.0
58.0
60,0
62,0
64,0
66,0
68.0
70,0
72,0
74,0
76,0
78,0
80,0
82,0
84/0
86.0
88,0.
'0,0
94.0
96.0
98.0
100.0
102.0
104,0
106.0
108.0
110.0
112.0
114.0
116.0
118.0
120.0
122.0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
148.0
150.0
152.0
156.0
158.0
160,0
16?, 0
164.0
166.0
168.0
170,0
172.0
174.0
176.0
178.0
180.0
C , ^vt •»&• V 1
2.8134E.OI
2,680tE.Ot
2.5617E-01
2.4565E.01
2.3631E.01
2.2801E-01
2.2070E.01
2,1436E»01
« MAa^.e>M<
,
2.0444E-01
2.0073E.OI
'.9775E-01
,9538E»Ot
,9355E.Ot
.9130E-0!
. -• - * u - V i
.9105E.01
.9176E-01
,9JOOE«01
.9473E.0.1
,9687E«01
,,9933E.01
2,0198E»01
2.0469E.01
2.074U.01
2.1010E-01
2.12&OE.01
9
-------
DG = 0.2 pm
X = 0.55 ym
fr
6,0
8,0
10,0
12,0
14.0
16,0
18,0
20,0
22,0
24,0
26,0
26,0
30,0
32,0
P(x.e)
7.2070E+00
36,
36.0
40,0
42,0
44.0
46,0
48,0
50,0
52,0
54.0
56,0
58.0
60.0
62.0
64,0
66,0
68,0
70,0
72.0
74,0
76,0
78,0
80,0
62.0
84.0
66,0
7,0798E*00
6.9261E+00
6,4889£tOO
6.2203E+00
5.9309E+00
5.6262£tOO
5,3l89£*00
5.0084E+00
4.7009E+00
4.1084£tOO
3,0638£iOO
2.8370E+00
2,6245£*00
2,4261£tOO
2,24l5£tOO
2,0703E*00
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.6294E+00
.3885E+00
,28|9EfOO
,!837EtOO
l,0108£tOO
9.3515E-01
6,6599£.0i
8.0278E.01
7.a500E-Oi
6.9220E.01
6.4401E.01
6.001U-01
5.6019E.01
5.2396E-01
4.9110E.01
496131E«0}
4.3433E-01
4.0988E.01
3.8777E-01
JL
'2,0
94.0
96,0
98.0
100.0
102.0
104.0
106.0
108.0
110,0
112.0
1U.O
116.0
118.0
120.0
122.0
124.0
126.0
llfl^O
130.0
132.0
134.0
136.0
13fl.O
140.0
142.0
144.0
146.0
148.0
1*0.0
152.0
154.0
156.0
158.'0
160.0
162.0
164.0
166.0
168,0
170.0
t72.0
174.0
176.0
178^0
160.0
P(x,e)
5.3372E-01
3,0644£.01
2.9500E-01
2.760U-01
2.6153E-01
2,557b£«01
2,5068£*01
2,4664£.01
2,4361£.01
2.3935E-01
2,3818£.01
2.3759C.01
2,3750£.0l
2,3790£.01
2,3876E«01
2,4008£.01
2,4166E«01
2,4407£*01
2,4666£«0t
2.4959E-01
2,5276£.oi
2,5609£«oi
2.5947E-01
2,6280£«01
2,6605£»01
2,6920£»01
2,7232£*01
2.7546E.01
166
-------
0.2 m
0.7 ym
e
P(x,e)
0,0
2.0
4,0
6,0
8,0
|0,Q
12,0
J4,6
U;o
16,0
20,0
22.'0
24,0
26,0
28,0
30,0
32,0
34,0
36,0
36,0
40,0
42,0
44,0
46,0
48,0
50,0
52 0
54,0
56,0
58,0
60,0
62,0
64,0
66,0
68,0
70,0
72,0
74,0
76,0
76,0
60.0
62,0
64.0
86,0
68.0
90,0
6,ill3E*00
6.0696E+00
6.0257E+00
5.9223E+00
5,7839E*00
5,6156E*00
5f4230E*Oo
5,2116E+00
4.9666E+QO
4.7525E400
4.5137E+00
4,2736EtOO
4.0352E*00
3,.B006E + 00
3,5724E*00
3.35l3EtOO
3.1384E400
2.9346E^OO
2,7402E*00
2,5556EtOO
2,3609EfOO
2.2163EtOO
2.0615EtOO
,9i64E+00
,7809E*00
,6546EtOO
.5370E*00
.4277EtOO
.3264E+00
,2325EtOO
,1456EfOO
,0652EtOO
9.9108E.OJ
9.2277E.OI
8.5991E.OI
8.0215E.01
7.4910E.01
7.0043E-01
6.5580E.01
6.1491E.Q1
5.7751E-01
5.4335E.01
5.1224E.01
4.B397E.01
4.5634E.01
4.35U£.01
0
96.0
*»8.0
too.o
102,0
104,0
106.0
106. 0
tto.o
112.0
114.0
116.0
llfi.O
120.0
122.0
124.0
126,0
126.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
14B.O
150.0
152.0
lSfl.0
156.0
158.0
160.0
162.0
164.0
166.0
168.0
170.0
172.0
174.0
176.0
178.0
180.0
3.9S36E-01
3.7851E.01
3.634AE-01
3.50UE-01
3.3636E.01
3.2806E»01
3.19Q7E.01
3,1132£*01
3,0471E*01
2.9917E-01
2.9403E-01
2,9099E.01
2,6820C*01
2,6616£»0t
2,648|£.ot
2.8395E-01
2.8436E-01
2,6526E.01
2,6669E»01
2.6652E.01
2,9075E»01
2.9331E.01
2.961SE.01
2,9922E»01
3,0247£.0l
3,056SE»01
3.093JE-01
3.1263E.Q1
3.1642E*01
3,2006E»Of
3.2375E.OI
3,275lE-Ot
3.3132E-01
3.3519E-01
3.3911EP01
3.4309E-01
3.4708E-01
3.5104E.01
3.5483E-01
3.5826E.01
3,6103E»01
3.6266E»01
3.6349E.01
167
-------
DG
X
0.3 ym
0.4 ym
P(x.e)
-S.
o.o
2,0
4.0
6.0
6.0
10,0
12,0
J4.0
16. 0
18,0
20,0
22,0
24,0
2b.O
28,0
J0,0
32,0
34,0
36.0
38.0
40,0
42,0
44,0
46,0
48,0
50,0
52,0
54 0
56,0
58,0
60,0
62,0
64,0
66,0
66,0
70,0
72,0
7«,0
76,0
78,0
80,0
82,0
84,0
*<>,0
88,0
'0,0
,!7l4Et01
,1377£*01
,0878gt01
,0274£*01
9 6110EtOO
8,9228£tOO
8.2342E+00
7.5621E+00
6.9175E+00
6.3078£*00
5.7376E+00
5.2096E*00
4,7243EtOO
4,2806E*00
3,8764£tOO
3.508BC+00
3,l747EtOO
2.8706E+00
2,3434EtOO
2.U62E + 00
.7273E+00
.5631E+00
.4167E+00
ti685E*00
1,0628E+00
9,6739£.01
7.3398E.01
6,?132E.01
5.2328E-01
4t8a5lE«Ol
4.4898E.01
3,8549£.0l
3.5785£»01
3.3339E.01
3.1202E-01
2.9315E-01
2.7601E-01
96.0
96.0
iOO.O
102,0
104.0
106.0
108.0
110.0
112.0
114.0
116.0
118.0
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134.0
136.0
136.0
140.0
142.0
144.0
146.0
14B.O
150.0
152.0
154.0
156.0
158.0
160.0
162.0
168.0
170.0
172.0
174.0
176.0
17B.O
180.0
.-
,8676£»01
,8030£«01
,7459£.01
,6979£-01
,6066£»01
.5893E.OI
,5674£-01
,5626E*01
.5631E-01
,5701E«01
.5850E-01
,
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.6786E-01
.7211E.01
.7658E.01
,8115E«01
u^u-T^wyj
9003E.01
9398E.OI
1.9739E.01
2.0027E.01
2.0289E.01
2,0560E»01
2 AAA/lC_/i4
2,1207£»01
2, 1569£.01
2.2051E-01
2,2667E.oi
2.3613E-01
2.4884E.01
2.6418E-01
2,7965£«01
2,9148£.01
2,9596E«01
168
-------
DG
X
0.3 vm
0.55 ym
0.0
2,0
4,0
6.0
»,0
10,0
12,0
14,0
16,0
16.0
20,0
23,0
24,0
26,0
26,0
30,0
52,0
34,0
36,0
36,0
40,0
42,0
44.0
46,0
48,0
50,0
52.0
54,0
56.0
56,0
60,0
62.0
64,0
66,0
68,0
70,0
72,0
74,0
76,0
78,0
60,0
82,0
64,0
86,0
86,0
90.0
o.
0
J1-0
94.0 ,
96,0 ,
98,0
100,0 ,
102.0 i
104.0 i
106.0 i
108.0 i
110.0 i
H2.0 <
114.0
116.0
118.0
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134,0
136.0
13*. 0
140.0
142.0
14U.O
146.0 I
148,0 «
150,0 i
152,0 i
154)0 i
156.0 i
158.0 i
160,0 I
162,0 i
164,0 I
166,0 i
168.0 i
170,0 i
172,0 <
174,0 *
176.0 c
178.0 I
160.0 2
P(A.e)
J.0092E.01
&.8540E.OJ
2.7148E.01
2.5893E.01
2.4762E.01
2.3746E.01
'.2640E.01
S.2039E.01
M335E.01
2.07UE.01
J.0176E.01
,97l!E.01
,9326E»01
.9023E-01
.8601E.01
.8651E-01
(8565E»01
,8527E«01
,6527E*Ol
,8557C«01
.8617E.01
,87i5g.oi
,886oE»Oi
.9060E-01
.9319E.01
,9635E-01
.9995E-01
!,0384E»01
>,0779E«01
!,1162E*01
i.isaoE.oi
»,18,214U*01
>,2ai8E-01
»,269«E«01
!,2992E«Ol
J.3341E-01
J.3779E.01
»,43fllE«01
!,5041E«01
I.5855E-01
f,6707E«Oi
I.7477E.01
!,8022E-01
!,8220E»01
169
-------
DG = 0.3 ym
X = 0.7 ym
0.
0,0
2,0
4,0
6,0
8.0
10,0
12,0
1 P(X»Q)
3,37951.01
3,20516-01
3,0484E«01
2.9085E-01
2.7843E-0!
2.6743E-01
2,5770E»01
2,
-------
DG ~ 0.5 pm
X s 0.4 ym
e
,o7o
2,0
M
6.0
8,0
10,0
12,0
14,0
16,0
16,0
20,0
22,0
24,0'
26,0
26,0
30,0
32,0
14,0
36,0
36.0
40,0
42,0
44,0
46,0
48,0
*0,0
52,0
54,0
*6|o
58,0
60,0
02,0
64,0
66,0
66JQ
70,0
72,0
74,0
76,0
78,0
*o;0
62,0
MO
H,0
68',0
'0,0
92.0
9fl.O
96.0
98.0
100,0
102.0
104.0
106.0
108,0
110.0
112.0
114.0
116.0
118.0
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
148,0
150.0
152.0
154,0
156,0
158.0
16fl,0
162.0
164.0
166.0
168,0
170.0
172.0
174.0
176.0
178.0
180.0
P(X,0)
t.miE-oi
.6467E-0!
,6026E»01
,5610E*01
.5192E-01
,4542E*0!
,4410£*0f
,4549£.0l
.5297E.O!
,549aE»01
,5634E*01
.5773E-01
.5995E.01
,6369E«0!
,69«7E«0!
,7739E»01
.8707E.01
,9810E«01
2,1010E«01
2,225|E»OI
2.3453E.01
2.4513E.01
2.5343E.01
2.5907E.01
2,6221E»01
2,6337E»0!
2.6363E-01
2,6504E»01
2.70U1E-01
2,B24SE»01
3,02«6E»01
3.2931E.O!
3,5824E*01
3.8154E-01
171
-------
DG
>
0.5 ym
0.55 ym
PU.0)
0.0
2,0
4.0
6,0
8,0
10.0
12,0
14,0
16,0
18,0
20,0
22,0
21,0
26,0
28,0
30,0
32,0
34,0
36,0
38,0
ao.o
42,0
50,0
52,0
5«,0
56,0
58,0
60,0
62,0
6<*,0
66,0
68,0
70,0
72,0
7«,0
76,0
76,0
80,0
82,0
8^,0
86,0
88,0
P(x,e)
2,42701*01
1.2926Ef01
1,248&E+Q|
1.1856E+01
1.033l£i01
9.5278E+00
8,7372£fOQ
7.9700E+00
7.2537E+00
6.5759E+00
5,3607EtOO
4,824l£*00
4.3352£tOO
3.89JOE+00
3,4952EtOO
3.1391E+00
2,82t5EtOO
2,5383E*00
2,0570E+00
1.85l8EtOO
1.6669E+00
!,5o03EtOO
l,3505EtOO
1.2172E+00
5t83oiE-01
3.8590E.OJ
3.3537E.01
3,t3t5E.Oj
2.9265E-01
96,0 «
9ft. 0 i
100,0
102,0
104,0
106.0
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110.0
112.0
114,0
116.0
118.0
120,0
122.0
124.0
126.0
128,0
130.0
132,0
134.0
136.0
138.0
140.0
142.0
14(1.0
146.0
148.0
150.0
152.0
154,0
156.0 i
15B.Q ,
160.0 i
162.0 i
164.0 i
166,0 ,
168.0 ,
170.0 ,
172.0 <
174,0 ,
176.0 i
178.0
180.0
>,1794E»0!
J.0729E-01
.9771E.01
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.8209E.01
.7596E-01
,708«E*01
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.598BE.01
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l,6046E«01
l,6256E«01
l,6465£«01
1.6702E-01
I.6996E-01
l,7373£-01
l,78aoE-oi
1.8382E.01
l|8969£.oi
l,9554E»01
2.0088E-01
2.0541E.01
2.0917E.01
2.1255E.01
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2.3973E-01
2.5363E.01
2.6937E.01
2.6453E-01
2,9585E«01
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172
-------
DG
X
0.5 urn
0.7 vm
£-
o.o
2,0
4,0
!'°
8.0
10,0
12,0
14,0
16,0
1«,0
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10,11
34,0
36,0
38,0
40,0
42,0
44,0
46,0
48,0
50,0
52,0
54,0
56,0
58,0
60,0
62,0
64,0
66,0
68'.0
70,0
72,0
74,0
76,0
78,0
80,0
82,0
84,0
86 0
88,0
90,0
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lt!202E*01
I.1099E*01
!,08!!£+0!
1,0381£*01
*,8557£*00
0
8,662U*00
8,0426£*00
7,429
-------
DG
X
1.0 ym
0.4 urn
0
070
2.0
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6.0
8,0
10,0
12.0
14,0
16,0
18,0
20,0
£2,0
24,0
26,0
28,0
JO.O
32.0
34,0
36,0
38,0
40,0
42,0
«4,0
46,0
48,0
50,0
52,0
54,0
56,0
58,0
60,0
62,0
o«,0
66,0
68,0
70,0
72,0
7«,0
76,0
78,0
80,0
82,0
84,0
86,0
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90,0
_
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S.4113E+01
2,84471*01
2«3027E*01
|,8552E*01
1,50B6E*01
1.2456E+01
1.0416E+01
B.7B82E+00
7.4B51E+OQ
6.4268E+00
5.5419E+00
a.7979EtOO
«,1993E+00
2,5i24g*00
2,2l96E*00
1.9634E+00
1.739lEtOO
I.5705E+00
1.1004E400
9.8316E.01
B.B292E-OI
*
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7.1528E-01
6.4210E-01
5,8359£.0i
5.4Q73E-OI
5,0907E»OJ
4,4058E
3.99I2E
3.6252E
01
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01
3.0725E-01
2.8732E.OI
2.7166E.01
2.5657E.01
2.3863E»01
2,!89U»OI
2,03I9E»01
e
92.0
94.0
96.0
98.0
100.0
102.0 1
104.0 1
106.0 1
108.0 1
110.0
112.0
114.0
116.0
118.0
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122.0
124.0
126,0
128.0
130.0
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146.0 i
148.0 j
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,B850E»01
2.0651E-01
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5.5496E-01
5.B431E-01
4.0679E.01
4.2au8E-Ol
4.3079E.01
4.3140E.01
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U.2428E.01
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tt.5529E.Ol
B,0015E»01
5.6003E.01
fa,l772E»Ot
6,45S3E»01
174
-------
DG
X
1.0 ym
0.55 ym
o.o
2,0
4.0
6.0
8,0
10,0
12.0
14.0
16,0
18.0
20,0
22.0
24,0
26,0 ,
28,0
50,0
>2,0
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)6,0
58,0
40.0
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50,0
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58,0
«0,0
62.0
64,0
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72,0
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76,0
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80,0
88,0
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86',0
88,0
90,0
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94.0
96.0
98,0
100.0
102.0
104,0
106.0
108.0
110.0
112.0
114,0
116.0
118,0
120,0
122.0
124,0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
148.0
15-0.0
152.0
154,0
156.0
158.0
160.0
162.0
164,0
166.0
168.0
170.0
172.0
174.0
176.0
178.0
180.0
2.0635E.01
1.9597E.01
1.8628£»0l
1.7669E.01
1.6786E-01
1.6063E.01
1.5509E.01
1.5061E-01
1.4693E.01
1,4«17E.01
1.4233E.OI
1.4092E.01
1,3922E»01
1.3674JE-01
1,3401E»01
1.3226E»01
1,3214E»01
1.3368C-01
1.3701E-01
1.4218E-01
1,48
-------
DG =
1.0 ym
0.7 \an
P(A*0)
P(A,e)
070
2,0
4.0
6,0
6,0
10,0
12,0
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16,0
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26,0
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60,0
62.0
64,0
66,0
68,0
70,0
72,0
74,0
76,0
78,0
60,0
82,0
84,0
86,0
88,0
90,0
1.733BE+01
1.5727E*01
1.4086E+01
1.2541E+01
J,ll37EfOJ
9,B76tȣtOO
8,747BE*OQ
7.7425E+00
6,8525EtOo
6.0661E+00
5,3728E*00
«,?626E+00
4,2212E+00
3,7355E*00
2.5B37E+00
2.2963E+00
2,0502EiOu
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,2224£fOO
.0982E+00
8,0176E»01
7.2439E-01
6,5781E«01
6.0167E-01
5.5381E.01
5.1072E.01
4.6956E.01
u irtfttiE.ni
!*-°
94.0
96,0
98.0
100.0
102.0
104.0
106.0
10B.O
110.0
112.0
114.0
116.0
118,0
120.0
122.0
124,0
126.0
12«.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
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148. 0
150.0
152.0
154.0
156.0
158.0
160,0
162.0
164.0
166.0
168.0
170.0
172.0
174.0
176.0
178.0
180.0
2.1356E.01
2.0541E.01
1.9747E.01
l,8897f.ot
1.8033E.OJ
1.7274E.Q1
1,6708E»01
1.6294E.01
1.5902E-01
1.5450E.01
1.4965E-01
1.4549E.QJ
1.4286E-01
.4183E«01
.4203E.01
,432lE-Ot
.4548E.01
,4878E«01
.5254E-01
,55B3E»01
,5fl04E»Ot
.5952E-01
,6128E»01
1.6458E-01
1.7023E-01
1.7822E-OI
i,8604E»01
1.9950E-01
2,1274£«0l
2.2758E-01
2,4328E«01
2.5818E-01
2.7048E-01
2,7930E«01
2.8452E.01
2,8662E«01
2.8696E.01
2.872BE.01
2.9067E.01
3.0172E-01
3,2426E«01
3.5778E.01
3,9b30C»01
4,2906E»01
4,4254E»01
176
-------
DG
X
2.0 ym
0.4 pro
_
o.o
2,0
4,0
6,0
M
10,0
12.0
»4,0
16,0
16,0
20,0
22,0
84,0
2J.O
26.0
10.0
12. 0
14,0
16.0
10.0
«6,0
«d,o
10.0
»2.0
S4.0
96,0
58.0
60,0
62,0
64,0
66.0
66,0
74,0
76,0
76,o
60,0
82,0
64,0
«O
68,0
'0,0
e
1.1765EtOl
5,01816*00
«.2at7EfOO
3.5817E+00
t.taise+oo
9.7606E.OJ
B.3096E-01
2.55HE.01
2.2709E.01
J.9407E.01
96,0
9«|o
100.0
102.0
104.0
106.0
10A.O
110.0
112,0
11490
116,0
116,0
120.0
122,0
124.0
126.0
I2A.O
130.0
132.0
m.o
13ft. 0
13*. 0
1«0.0
142.0
144.0
146.0
14ft. 0
150.0
1S2.0
154.0
156.0
158.0
160.0
162.0
104.0
166.0
168.0
170.0
172.0
174.0
176,0
178.0
180.0
177
-------
DG = 2.0 ym
X = 0.55 ym
0,0
6,0
6,0
10.0
12,0
14,0
16,0
16,0
20,0
22,0
24,0
26,0
28,0
30,0
32,0
34,0
36,0
38,0
40,0
42,0
44,0
"6,0
««,0
50,0
52,0
54,0
56,0
58,0
60,0
62,0
64,0
66,0
68,0
70,0
?2,0
74,0
76,0
78,0
80,0
82,0
84,0
86,0
88,0
6.7621E+01
5,6399E*Oi
4,069oEf01
2,9J72E*01
2,1412£f01
1.606SE+01
1.2359E+Q1
9.8339E+00
8,0182E*00
6.6206E+00
5.6044E+00
4.B621E+00
4.2l25EtOO
3.6039E+00
3,J33l£tOO
e
2,«B22E+00
2,183?E*00
1.6B26EtOO
1..5013E + 00
1,3322E*00
I,2l3l£t00
l,loT3£tOO
T,4411E«01
6.5327E-01
6,178fiE.Oi
4,92516-01
4.5052E.01
4,t562E.Ol
3.79JJE.01
3.4123E.01
3t095lE«01
2.8928E.01
2,5372E.Ol
2.3570E.01
94,0
96.0
9«.0
100.0
102.0
104.0
106.0
108.0
110.0
112.0
114.0
116.0
llfl.O
120.0
122.0
124.0
126.0
126.0
130.0
132.0
134.0
136*0
138.0
140.0
142.0
144,0
146.0
148.0
150.0
152.0
154.0
156.0
2.0316E.01
160.0
162.0
164 o
166.0
168.0
170.0
172.0
174,0
176.0
178^0
ifio.o
P(x.e)
1,9138E.01
1.8175E.01
,
,5967E»01
,49276.01
.4230E.01
.3846E-01
.3435E.01
.2933E.01
,2580E»01
.2472E-01
,2443E»01
,2388£»01
,2052E»Ol
,1516E.01
.1200E.OI
.1194E.01
,1315E»01
,1670E«01
,36Sl£.01
.5063E-01
.5267E-01
,5578g.01
.5959E.01
.8413E.01
2,0772E«01
2.36S2E-01
2,732iE«01
3.172SE-01
,
3.9039E-01
4,2566E.Ol
4,6030E»01
4.8391E.01
178
-------
DG
X
2.0 pm
0.7 un
L
0,0
2,0
4,0
6,0
8,0
10,0
12,0
14,0
16,0
18,0
20,0
22,0
24.0
26,0
28,0
30,0
52,0
14,0
36,0
38,0
40,0
«2,0
50,0
52,0
54.0
56,0
58,0
00,0
62,0
04,0
66,0
68,0
70,0
2,0
.O
3,2228£tOl
2.5005E+01
1.9507E+01
l,2536E+Oi
.
8,597«E+00
7.2296E+00
6.1636E+00
5,302«£tOO
S.5710E+00
3,l378£4oo
2.110UE+00
.87696^00
,3}2BE+00
,19395*00
,0590E*00
9,
-------
DG
A
5.0 ym
0.4 ym
G
o.o
2.0
10.0
12,0
14,0
16,0
16,0
20.0
22,0
24,0
26,0
26,0
30,0
52.0
34,0
36,0
18,0
40,0
42,0
44,0
46,0
46,0
50,0
52,0
54,0
56,0
58,0
60,0
62,0
64,0
66,0
*6,0
70,0
72,0
74,0
76,0
78,0
80,0
62,0
6fl,0
86,0
68,0
90,0
0
.O
98.0
100.0
102.0
104.0
106.0
108.0
110.0
112,0
114.0
116.0
118.0
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
1«2,0
144.0
146.0
148.0
150.0
152.0
156.0
156.0
160.0
162.0
164.0
166.0
168,0
170.0
172.0
17«,0
176,0
178.0
180.0
p(x.e)
1,19081-01
1.2259E.01
1,1205E»01
9.7706E.02
9,8066E*02
9.6403E-02
•tt * t C <* <%
7.7468E.01.
7.0390E-01
7.6J04E-01
fi.5001E.01
1,1466E*00
1,0917E*00
9.9826E-01
180
-------
DG = 5.0
X = 0.55
0,0
2,0
4.0
6.0
8,0
10,0
12,0
14,0
16,0
16,0
20,0
22,0
24,0
26, Q
26,0
30,0
32,0
34,0
36,0
36,0
40,0
42,0
44,0
46,0
46,0
50,0
S2,0
54,0
56,0
56,0
60,0
62,0
64,0
66,0
66,0
70,0
72,0
74',0
76,0
78.0
80,0
62,0
84,0
86 0
86,0
'0.0
!*-°
*4,0
«6.0
«8,0
100.0
102.0
104.0
106.0
lOfl.O
110,0
112,0
114,0
116.0
118.0
120.0
122.0
124.0
126.0
126.0
130.0
132.0
134.0
136.0
136.0
140.0
142.0
144.0
146.0
148.0
150.0
152.0
154,0
156.0
158.0
160.0
162.0
164.0
166.0
168,0
170,0
172.0
17
-------
DG
X
5.0 ym
0.7 ym
56,0
60,0
62,0
6«,0
66,0
66,0
70,0
72,0
74,0
76,0
78,o
80,0
62,0
84,0
86,0
88,0
90,0
0
0,0
2,0
4,0
6,0
6,0
10,0
12,0
i4,0
16,0
18,0
20-.0
22,0
24,0
26,0
28,0
30,0
32,0
34,0
36,0
36,0
«2,0 l,3993£tOO
50,0
52,0
2.3Q01E+00
2.1436E+00
2,15B6E*00
1,9176E*00
1.6656E+00
8.9965C-01
7,5557e-01
6,6473E»01
6,6536E»01
5,5700E-01
fl.6l99g.0l
3.6784E-01
3.6199E.01
3.3127E.01
2.7367E-01
2.2102E-01
2,17a7E.01
2,230SE»01
2.15266-01
96,0
96,0
100.0
102.0
104.0
106.0
O8.*0
10.0
12.0
14.0
16.0
18.0
120.0
122.0
124.0
126.0
126.0
130.0
132.0
134.0
136,0
138.0
140.0
142,0
144,0
146.0
146.0
150.0
152.0
154.0
156.0
156.0
160,0
162.0
164.0
166.0
168.0
170.0
172.0
174.0
176.0
17«.0
160.0
P(*.e)
.7560E.01
,5698E»01
,4065E»01
.4109E.01
,4722E«01
.3075E-01
P * » W fc •• ^ V 1
,0241E«01
.0693E.01
,2510£*01
,364bfcbwvc.
5672E-02
,1237E.01
,2433E»Q1
,3612E»01
,38326.01
,4608E*01
,6626E»01
,9556£»01
2,3148E*01
2.7975E-01
3,5564£«01
4,3107E«01
5.1053E-01
6.1903E-01
7,5079£.01
—-,v— • w u. —-w •
S.912UE.01
9.4776E-01
6,8497E«01
6,236lE»Ot
6,3002^.01
9,1U8£-01
1,0573E*00
1.19B1E400
182
-------
DG = 6.0 yffl
X = 0.4 pro
9
-------
DG = 6.0
A = 0.55
5.9«37Et02
2.3864E+02
8.4333E+01
3.6464E+01
1.9598E+01
t,1672E*Oi
7.3511E+00
5.3109E+00
4.1334E+00
3,3929E*00
3.20.12E + 00
2.5045E+00
2.1333E+00
2.0002E+00
2.1568E+00
,«438EtOO
,3488£tOO
,3234E+00
0.0
2,0
4,0
6,0
8,0
10,0
12,0
14,0
16,0
18,0
20,0
22,0
2«,o
26,0
28,0
30,0
32,0
34,0
36,0
38,0
«0,0
42,0
44,0
«6,0
48,0
50,0
52.0
54,0
56,0
58,0
60,0
t>2,0
*4,0
66,0
efl,0
70,0
72.0
7^,0
76,0
78.0
B0,0
82,0
84,0
86,0
90,0 1.6071E.01
8.4175E-01
5,9678£.01
6.0795E-01
5,8605E-01
5.8777E-01
4.6363E-01
4.0276E.01
3.7129E.01
3.4780E-01
3,39i£E.Oi
3.4Q18E.01
2.5823E.OJ
2.2744E.OJ
i§8408E.Ol
1.8516E.01
94.0
96.0
98.0
too.o
102.0
104.0
106,0
108.0
110.0
112,0
114.0
116.0
118.0
120,0
122.0
124.0
126,0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
148.0
150.0
152.0
154.0
156.0
158,0
160.0
162.0
164.0
166.0
168,0
170.0
172.0
174.0
176.0
178.0
180.0
P(x.e)
,5174E»01
,2810E»01
.1275E.01
.0254E.01
,0532E»01
9,75561.02
8.7953E.02
9,8605E»02
8.9522E.02
8,5131E»02
7.6283E.02
6,8a89E.02
7,8401E«02
8.0501E-02
7.3009E.02
7.0228E-02
6.9672E.02
6,9512E»02
5,0821E»02
f i o e * f n ^
7,4026E*02
7,7631E«02
8,4944E*02
7,7718£.02
7.8121E-02
• < /I Q >* r- A I
9.03S7E.01
9.2176E.01
9.1178E-01
9.9483E-01
1,1056E*00
1,1667E*00
184
-------
DG
X
6.0 ym
0.7 yn
0,0
2,0
4.0
6.0
M
10,0
12.0
14,0
16.0
ie,o
20,0
22,0
24.0
26,0
28,0
50,0
36,0
38,0
40,0
42,0
44,0
46,0
48,0
*0,0
52,0
54,0
*6.0
58,0
60,0
62,0
64,0
66.0
68', 0
70,0
72,0
74,0
76,0
78,0
80,0
82,0
»4,0
86,0
88,0
90.0
P(x,e)
3.5921E+02
1.8132E*02
7.9809E+01
(1.0735E + 01
2.2247E*01
1.2830E+01
8,6730EtOO
7.2267E+00
5.3723E+00
4,l778EtOO
3,7811E+00
3,6245E400
2,9216E*00
2,5204EtOO
2.4463E+00
2,4644E^OO
l.9509£*00
,6956EtOO
,6065EtOO
,4773E*00
.2424E400
,U10EtOO
R.66bJE.01
7.5106E.01
6.5813E-01
6,52»7E.01
5.5942E-01
a,S480E«01
4.6734E.01
4.6117E-01
3.7656E-01
3.6795E-01
3,0608£»0i
2.4464E«01
2.5B92E-01
2,3868£.0l
2.4J9QE-01
2.5612E-01
P.23276-01
l.*93l£*01
1.6677E-01
'2,0
^4.0
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98.0
100.0
102,0
104,0
106.0
108.0
110.0
112.0
114.0
116.0
llfl.O
120.0
122,0
12
-------
DG - 10.0 ym
A = 0.4 ym
e_
0,0
2.0
a.O
S«°
8,0
10,0
12.0
14,0
J*,c
18,0
20,0
22,0
24,0
26,0
26,0
30,0
32,0
34.0
36.0
38,0
40,0
42,0
44,0
46,0
48,0
50,0
52,0
54.0
56,0
56,0
60,0
62,0
64,0
66,0
68,0
70,0
72,0
74,o
76.0
78.0
80,0
82,0
84,0
86,0
88,0
90,0
6
3,3«46E+02
6,0017E*01
2,0556E*01
l,0354.E*Oi
7.2783E+00
4,99Q5E*00
4,45526*00
4,b422E*00
S.3900E+00
2,923BE*00
3,3278E*00
2,5297E*00
2,1617E*00
.7068E+00
,4710E*00
,4o26EtOO
,0522£tOO
9,4500E»01
8,6352£»01
7,7440£*0|
6,3026|.01
5,0728£.Q1
5.5583E.01
3.987U.01
3,3947£.0l
3.1150E«01
2,3358£.0i
2.0913E.01
,7i60£«0l
,39Q7£«OJ
C2262£.0|
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96,0
loo, e
102,0
106.0
108,0
110,0
112.0
114,0
U6.0
11».0
120,0
122.0
124.0
126.0
126.0
130.0
132.0
136,0
13B.O
140.0
142,0
144.0
146,0
148.0
150,0
152.0
154,0
156,0
158.0
160.0
162.0
164,0
166.0
168,0
170,0
172.0
174.0
176,0
178.0
180.0
P(X,9)
0.7944E.02
It0204£.0i
6.8620E.02
6,22126. 02
7,i707e-02
6.8097E.02
6,69Q5E«02
5,4047E.02
4.6377E-02
«,5968E»02
4,5963E*02
4,5970£»02
3.954U.02
4.2393E-02
3.1168£.02
3,3250£»02
4,8081E»02
4,584S£»02
493432E»02
6,137?£.0?
6,5830E»02
1.2595£.0t
292242E»01
3.4421E-01
5.1661E.01
7t6899g.01
8.3350E-01
5.7081E.OI
6,2542£.oi
7,2376£.0l
7,5246£»01
1,4827E*00
l,7329g*00
9,1?32£»01
186
-------
DG
X
10.0 ym
0.55ym
0.0
2.0
6.0
10,0
12.0
1/4 . 0
16,0
16,0
20,0
22,0
24,0
26,0
26.0
30,0
32,0
34,0
36,0
36,0
40,0
42,0
44,0
46.0
48.0
50,0
52,0
54,0
56,0
56.0
60,0
02,0
64,0
• 6,0
68,0
70,0
J2, 0
74,0
76,0
78,0
60,0
62,0
6M
66.0
88,0
'0,0
_
2*-°
'4,0
96,0
'8.0
100,0
102.0
104.0
106.0
108.0
110,0
112,0
114.0
116.0
tie.o
120.0
122.0
124.0
126.0
128.0
130.0
132.0
134.0
136.0
138.0
140.0
142.0
144.0
146.0
148.0
150.0
152.0
154.0
156.0
158.0
160.0
162.0
164.0
166.0
108.0
170.0
172,0
174.0
176,0
178,0
180.0
P(A.e)
},U20E.01
1.0371E-01
9.3618E.02
7.80SOE.02
7,18J7E.02
6.3150E.02
6.6977E-02
S.7462E.02
5.15SSE-02
5,3666E«02
S.5367E.02
5.S315E.02
4.7693E.02
4,8S07E»02
4.307SE.02
5.1935E.02
4.2663E.02
3.5343E-02
4.2719E-02
4,5
-------
DG = 10.0 ym
A = 0.7 ym
0.0
2,0
4,0
6,0
6,0
10,0
12,0
14.0
16,0
18,0
20,0
22,0
24,0
26,0
26,0
30,0
32,0
J«,0
36,0
36.0
«0,0
-------
APPENDIX C
PLUME DISCOLORATION PARAMETERS FOR VARIOUS N02 LINE-OF-SIGHT
INTEGRALS AND BACKGROUND CONDITIONS
This appendix contains the following plume-discoloration parameters
> Blue-red ratio
> Plume contrast (A = 0.55 ym)
> Plume perceptibility A£ (L*a*b*).
These parameters were calculated using PLUVUE, the plume visibility
model, for a scattering angle of 90°,* an assumed horizon-sky viewing
background, and the following Input conditions:
> N02 Hne-of-slght Integrals from 1 x 102 to 5 x 107 yg/m2.
> Plume-observer distances rp, and background visual ranges
r of 5, 10, 20, 50, 100, 150, 200, and 250 km.
V0
For plumes that are predominantly N02 (e.g., plumes from well-
controlled power plants), the values of these parameters do not vary
significantly with scattering angle.
189
-------
BACKGROUND VISUAL RANGE (KM) 10.00
PLUME-OBSEP.VEll DISTANCE ( KN) 5.O0
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
< UG/M**2)
1 . OE+02
2.OE+02
5 . 0E+02
1 . OE+03
2.0E+03
3 . 0S+03
l.OE+04
2.OE+04
5.0E+04
1 . 0E+03
2.0S+05
3 . OE+05
1 . OE+06
2.0E+06
5 . OE+06
1 . 0E+07
2.0E+.07
5.0E+07
1.000
1.000
1 . 000
1.000
1.000
1.000
1.000
.999
.998
.996
.992
.982
.971
.961
.960
.970
.992
1.049
-.OOO
-.OOO
-.OOO
- . OOO
-.009
-.000
-.OOO
-.000
- . 00 1
-.002
- . OG3
-.011
-.021
-.040
-.079
-.114
-.136
-. 141
.000
.001
.002
.004
.007
.018
.037
.073
. 1O1
.355
.684
1.533
2.587
3.883
5.761
7.422
8.625
9.727
-------
vo
BACKGROUND VISUAL RANGE CKTO 19.99
FLUKE-OBSERVER DI STANCE (KM) 1O.OO
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1.0E+02
2.0E+02
3.0Ei-02
l.OE+03
2.OE+03
5 . OE+03
l.OE+94
2.0E+04
5 . OE+O4
1 . 0E+03
2.0E+05
3 . OE+03
1 . OE+Q6
2.0E+06
3 . OE+06
J.OE+07
2.0E+07
5 . OE+07
1.000
1.000
1.000
1.000
1.000
1.000
1.000
l.OOO
1.000
LOGO
l.OOO
.999
.999
.999
1.000
1.003
1.009
1.023
-.OOO
-.000
-.009
-.000
-.OOO
-.009
-.000
-.OOO
-.OOO
-.OOO
-.001
- . OO2
-.003
-.006
-.011
-.016
-.019
-.020
.000
.000
.OOO
.OOO
.OO1
.001
.OO3
.OO5
.013
.026
. O3O
. 118
.218
.3C7
.776
1. 151
1.497
1.901
-------
BACKGROUND VISUAL RANGE (KM) 20.00
FLUKE-OBSERVED DISTANCE (KM) 3.O0
2)TNTEGRAL BLUE-USD RATIO CONTRAST DELTA E
1 . OE-f-02
2 . 03+O2
5 . OE+92
1 . OE+03
2. OE+03
5 . 0E+03
1.0E+04
2.0E+04
5 . 0E+04
1 . 0E+05
2. OE+05
5. OE+05
1.0E+06
2.0E+06
5 . OE+06
1 . OE+07
2.0E+07
5.0E+07
l.OOO
1.000
1.000 '
l.OOO
1.000
.999
.990
.996
.991
.901
.960
.922
.374
.324
.302
.318
.334
.962
- . OO'J
-.OOO
-.000
-.003
- . 000
-.oeo
-.00!
-.001
- . 003
-.006
-.012
-.030
-.057
-. 106
-.211
- . 30-1
-.362
-.376
.001
.002
.060
.011
.021
.053
. 105
.209
.517
1.017
1.965
4.437
7.531
11.153
14.719
17. 127
18.728
19.729
-------
40
BACKGROUND VISOAI, ItAKGE >4.
* oV™
6.9O9
7.951
-------
BACKGROUND VISUAL RANGE (KM) 20.09
PLUME-OBSERVER WISTANCE (KM) 15.00
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UG/M**2>
1.0E+O2
2.0E+62
3.05+42
1 . 0E+03
2.0E+03
5.0E+03
1 . OE+04
2.0E+04
3.0E+04
1.0E+03
2.0E+03
5 . OE+03
1 . 0E+06
2.05+06
5.0E+06
1.0E+07
2.0E+07
3 . OE+07
1.000
1.000
1 . 000 ' '
1.000
1.000
1.000
1.000
1.000
1.000
.999
.999
.997
.993
.994
.996
1.001
1.013
1.042
-.000
-.009
- . 000
-.000
-.00*?
-.009
-.000
-.000
-.000
-.001
-.002
-.004
- . 003
-.015
-.000
-.043
i
-.031 '
- . 053
.000
. 000
.000
.001
.001
.003
.007
.013
.032
.064
•. 124
.233
.302
.045
1.601
2.313
2.836
3.473
-------
BACKGROUND VISUAL RAlfCE CKfO 29. OO
FLUKE-OBSERVER DISTANCE 2O.OO
(NO2) JiTrECRAL BLUE-RED RATIO CONTRAST DELTA E
<:UC/M*#2>
1 . 0E+O2
2.0E+02
5.0E+32
1. OE+03
2. OE+03
5 . OE+03
1 . OE+O4
2.OE+04
G . OE+O4
— • 1 . OE+03
vo
01 2. OE+03
G . OE+05
1 . OS+C6
2.OE+O6
3 . OE-s-OO
1 . OE+07
2.0E+07
5 . OE+07
l.OOO
1.000
1.009
1.000
1.000
1.000
1.000
l.GOO
l.OOO
l.OOO
LOGO
.999
.999
.999
1.OO1
1.004
1.010
1.024
-.000
-.000
-.000
-.000
-.000
-.000
-.000
- . OCi">
-.000
-.000
-.001
-.002
-.003
-.006
-.011
-.016
-.019
-.020
.000
.000
.000
.000
.000
.001
.002
.OO4
.010
.019
.037
.088
. 106
.303
.629
.936
1.217
1.341
-------
BACKGROUND VISUAL RANGE (KM) 50.OO
PLUME-OBSERVER DISTANCE (IINTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1 . 0E+02
2.0E+02
5 . OE+02
1.02+03
2.0E+03
3 . 0E+03
l.OE+04
2.0E+04
5.0E+04
1 . 0E+05
2.0E+0S
5 . 0E+03
1 . 0E+06
2.0E+06
5.0E+06
1.0E+07
2.GE+07
5 . 03+O7
1.000
1.000
1.000
1.000
.999
.998
.995
.991
.977
.956
.913
.813
.693
.574
.504
.515
.552
.669
- . OOO
-.OOO
-.000
-.000
-.000
-.001
-.001
-.002
-.006
-.on
-.022
-.053
-. 103
-. 190
-.389
-.546
-.651
-.676
.002
. 004
.010
.019
.009
.096
. 193
.384
.953
l.BiJO
3.661
0.449
14.795
22.827
29.O43
02.047
33.594
33.7B7
-------
vo
BACKGROUND VISUAL RANGE (KM) 89.99
PLUIiE-OBSERVER DISTANCE CKM) 19.99
INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1 . 0E+02
2. OE+02
3 . OE-t-02
l.OE+03
2.OE+O3
5.OE+03
1 . OE+04
2.0E+04
3 . OE+04
1 . OE+05
2.0E+05
3 . 0E+O3
1 . 0E+06
2.0E+06
3.0E+06
l.OE+07
2.0E+07
3.0E+07
l.OOO
1.000
1.000
1.000
1.000
.999
.998
.993
.908
.977
.956
.904
.844
.783
.754
.771
.811
.932
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.004
-.007
-.013
-.006
-.069
-. 120
. -.257
-.369
-.440
-.457
.001
.002
.005
.011
.021
.053
. IO6
.212
.524
1.032
1.9Q6
4.524
7.718
11.499
15.267
17.968
19.O70
20.912
-------
BACKGROUND VISUAL RANGE (KM) 50.00
PLUHE-OBSHRYEH DISTANCE (KM) 15.00
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UC/M**2>
1 . OE+02
2.0E+02
3 . OE+02
1 . 05+03
2.0E+03
5 . OE+03
1 . 0E+04
2.0E+O4
3.0E+G4
-• 1 . OE+03
IO
00 2.0E+05
5 . 0E+05
l.OE+06
2.0E+06
5 . 0E+06
1 . 0E+07
s
2.0E+07
3.0E+07
1.000
1.000
1.000
1.000
1.000
.999
.999
.998
.994
.988
.978
.951
.921
.890
.330
.896
.
.931
1.0?2
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.003
-.005
-.010
-.024
-.047
-.087
-. 174
-.250
-.298
-.309
.001
.001
.003
.006
.012
.029
.059
. 117
.239
.568
1 . 095
2.462
4. 162
6. 198
B.Gf.B
1 1 . 295
12.9T1
14.111
-------
vo
VISUAL. RATTCE
rLt/rrE-op.sEnvr;R DISTANCE ' KTI> 20.00
2> INTECftAL DLVE-nr;i> 1JATIO CONTRAST DELTAE
1 . 07>
-------
UACWIIOUND \-ioUAL RANGE f KM> "o '"»
I'LUFZC-OBSERVEIl DISTANCE ( KPi) 3O.OO
(WO2) IWTSC.Ij'iL BLUE-RED RATIO CONTR.1ST DELTA E
i.OE+02
2.0Z+02
5 . PE-.-02
1 . OE+03
2.OE+03
3.OE+03
1 . OE+04
2.0E+04
5 . OE+04
ro 1 . OE-^OS
o
0 2.0E+05
5.0E+05
1 . 0E+06
2.0C+06
3.0E+06
1 . OE-J-07
2.0EH-07
5.0E-1-07
: . ooo
1.000
1.000
1.000
1 . 000
1.000
1.000
1.000
.<>99
.990
.997
.994
.990
.987
.990
.999
1.016
1.061
-.OOO
-.000
-.000
-.OOO
-.OOO
-.OOO
-.OOO
-.OOO
-.001
-.002
-.003
-.008
-.015
-.027
- . 054
-.077
-.092
-.096
.OOO
.000
.001
.001
.002
.003
.010
.021
.051
. 101
. 195
.445
.784
1.306
2.449
3.515
4.309
5.036
-------
l»
BACKGROUND VISUAL. RANGE (KM) 5O.O9
FLUKE-OBSERVER DISTANCE (KM) 49.OO
2) INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1.0C+02
2.0E+02
3.0E+02
l.OE+03
2.0Ei-03
5 . OE+03
1 . OEr-04
2.0E+04
5.OE+04
l.OE+05
2.OE-I-05
3.OE+03
1.3E+06
2.OE+06
5.0E+06
1 . OE+07
2.OE+O7
5.OE+07
1.000
1.000
1.000
1. 000
1.000
l.OOO
1.000
i.oeo
l.OOO
l.OOO
.999
.999
.990
.998
1.000
1.006
1.016
1.042
-.000
-.000
-.000
-.000
-.OGO
-.000
-.OOO
-.OOO
-.OOO
-.001
-.OO1
-.003
-.007
-.012
-.025
-.035
-.042
-.044
.000
.OOO
.000
.000
.001
.002
.004
.OO7
.018
.036
.071
. 168
.313
.567
1. 158
1.699
2. 147
2.614
-------
BACKGROUND VISUAL RANGE (KM) 50.90
PLUME-OBSERVER DISTANCE (KM) 50.O0
(N02)INTEGRAL BLUE-RED KATIO CONTRAST DELTA E
l.OE+02
2.OE+02
5.0E+92
1 . 0E+03
2.0E+03
5 . 0E+03
1 . OE+04
2 . 0E+04
3 . 0E+04
ro 1 . 0E+09
O
1X5 2.0E+05
5.0E+05
1 . 0E+06
2.0E+06
S . 0E+06
1 . OE+07
2.0E+07
S . 03+07
1.000
1.000
1.000
1.000
1.000
1.000
i.oeo
1.000
1.000
1.000
1.000
1.000
1.000
i.oeo
1.002
1.003
1.011
1.026
- . 000
-.000 .:
-.oco
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.003
-.006
-.011 .
-.016
-.019
-.020
.000
.OOO
.OOO
.OOO
.000
.001
.002
.003
.098
.015
.O3O
.073
. 141
.266
.556
.826
1.076
1.364
-------
BACKGROUND VISUAL RANGE CKH) 199.9
PLUME-OBSERVER DISTANCE (KM) 5.OO
INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
('JG/TI*#2>
1 . 0E+02
2.0E+02
5 . OE+02
1.0E+00
2.0E+03
5.0S+03
1 . 0E+04
2.0E+04
5.0E+0*
1 . 0E+05
2:0E+95
3 . 0E+03
l.OE+06
2.0E+06
5.0E+06
1 . OE+07
2.OE+07
3 . OE+07
1.000
1.000
1.000
.999
.999
.997
.094
.988
.970
.941
.006
.750
.092
.427
.029
.034
.061
.453
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.003
-.007
-.013
-.027
-.063
-. 123
-.231
-.462
-.664
-.792
-.022
.002
.005
.012
.024
.047
. 118
.205
.470
1. 167
2.3O8
4.514
10.556
18.892
30.283
41.307
43 . 263
44.332
43.992
-------
BACKGROUND VISUAL RANGE (KM) 100.0
PLUIIE-OBSERVER DISTANCE (KM) 10.00
(i;02) INTEGRAL BLUE-RED RATIO CONTRAST DRLTA S
1 . OE+02
2 . 0E+02
3 . 0E+02
1 . 0E+03
2.03+03
5 . OE-i-03
1 . OE+04
2.0E-T04
5 . 0E+04
1 . OE+05
2.0E+05
3 . 0E+05
1 . 0E+06
2.0E+06
3 . OE+06
1 . 0E+07
2.0E+07
5 . OE+07
1.000
l.OOO
1. 000
l.OGO
.999
.998
.096
.992
.979
.959
.922
.020
.719
.600
.545
.559
.598
.726
-.000
-.000
- . 000
-.000
-.000
-.001
-.001
-.002
-.006
-.011
-.022
-.054
-. 103
-. 190
-.380
-.546
-.651
-.676
.002
.003
. 009
.017
.034
.086
. 171
.341
.845
1.668
3.246
7.478
13.060
20.0O1
26 . 427
29 . 246
3 1 . 489
32. 139
-------
BACKGROUND VISUAL. RANGE (KH> 1OO.9
PLUME-OBSERVER DISTANCE (KM) 13.O9
(NO2)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
( UCXH**2>
1.0E+02
2.0E+02
3 . 0E+02
1 . 0E+03
2.0E+03
3.0E+03
1.0E+04
2.0E+O4
3 . OE+04
1 . OE+O3
2.0E+03
3 . 0E+03
1 . 0E+06
2 . OE+O6
5.QS+06
1 . OE+07
2.0E*07
3.0E+07
1.000
1.000
1.000
1.000
.999
.999
.997
.994
.986
.972
.946
.382
.807
.732
.694
.711
.754
.039
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.003
-.009
-.018
-.044
-.083
-. 156
-.312
-.440
-.336
-.336
.001
.002
.006
.012
.023
.002
. 124
.247
.613
1.207
2.340
3.333
9. 177
13.823
18.429
21.663
24.063
23.152
-------
BACKGROUND VISUAL RANGE (KM) 100.0
PLUME-OBSERVER DISTANCE (KM) 2O.09
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UGXM**2)
1 . 02+02
2.GE+02
5 . 0E+02
1 . 0E :-03
2.0E+03
5.0E+03
1.0E+04
2.0E+04
5.0E+04
IN) 1 . 0E+05
O
°* 2.0E+03
O.OE+05
l.OE+06
2.0E+06
3.0E+06
1 . 0E+07
2.0E+07
5.0E+07
l.OOO
1.000
1.000
1.000
1.000
.099
.998
.996
.990
.931
.963
.919 '*•
.860
.817
.795
.313
.836
.986
-.OOO
-.000
-.000
-.000
-.000
-.000
-.001
-.002
- . 004
-.007
-.015
-.036
-.070
-.128
-.257
-.370
-.441
-.457
.001
.002
.00.->
.009
.018
.045
.090
. 130
.445
.874
1.691
3.829
6.528
9.768
13.532
16.789
19.091
20.332
-------
BACKGROUND VISUAL, RANGE (KM) 1OO.9
PLUME-OBSERVER DISTANCE (KM) 3O.O9
INTEGRAL BLUE-RED RATIO CONTRACT DELTA E
1 . 0E+02
2.0E+02
5 . 9E+02
i.eiM-03
2.0E+03
3.0E+03
l.OE+04
2 . 0E+94
5 . 0E+O4
ro 1 . OC+O3
O
"^ 2.0E+05
3 . OE+95
1 . OE+06
2.0E+06
5 . OE+06
1 . QE+07
2.0E+O7
5.0E+07 '
1 . 000
1.000
1.000
1.000
l.OOO
l.OOO
.')99
.990
.993
.991
.983
.962
.939
.916
.910
.928
.964
1.071
-.000
-.000
-.000
-.000
-.OOO
-.000
-.001
-.001
-.003
-.003
-.010
-.024
-.047
-.087
-. 174
-.250
-.290
-.310
.000
.001
.002
.005
.O1O
.024
.048
.095
.235
.4f»2
.891
2.O07
3.413
3. 190
8.056
10.828
12.710
13.942
-------
t\>
BACKGROUND VISUAL RANGE (KM) 100.0
PLUME-OBSERVER DISTANCE (KM) 40.00
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1.0E+02
2.0E+02
5 . 0E+02
1 . 0E+C3
2.0E+03
5 . OE+03
1.0E+04
2.0E+04
5 . 0E+04
1.0E+05
2.0E+05
5 . 0E+03
1 . 0E+06
2.0E+06
5 . 0E+06
1.0E+07
2.0E+07
5 . OE+07
1.000
1.00O
1.000
1.000
1 . 000
1.000
1.000
.999
.998
.996
.992
.982
.972
.962
.963
.978
1.007
1.089
-.000
-.000
- . (100
-.000
-.000
-.000
-.000
-.001
-.002
- . 003
-.007
-.017
-.032
-.059
-. 118
-. 169
-.202
-.209
.000
.001
.001
.003
.005
.013
.026
.051
.126
.248
.479
1.035
1.872
2.981
5 . 205
7.321
8.770
9.852
-------
BACKGROUND VISUAL. RANGE
-------
BACKGROUND VISUAL RANGE (KM) 100.0
DISTANCE (KN) 100.0
BLWE-R3D RATIO CONTRAST DELTA E
1 . 0E+02
2.0E+02
5 . 0E+02
1 . 0E+03
2.0E+03
5 . 0E+03
1 . 0E+04
2.0E+04
5 . OE+04
ro 1 . OE-K-5
0 2.0E+05
5 . 0E+05
1.0E+06
2.03+06
5 . OE+06
1 . OE+07
2.0E+07
5 . 0S +07
1.000
1.000
1.000
1.000
1.000
t.000
1.000
1.000
l.OOO
1.000
1.000
1.000
1.000
1.001
1.003
1.006
1.012
1.027
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
- . 000
-.00J
-.002
-.003
-.006
-.Oi2
-.017
- . 020
-.020
.000
.000
.000
.000
.000
.001
.002
.003
.008
.015
.030
.075
. 14-6
.276
.569
.841
1.098
1.392
-------
ro
BACKGROUND VISUAL RAWGE (KPD ISO.9
PLUME-OBSERVER DISTANCE (KM) 5.OO
(NO2)INTEGRAL BLUE-RED RATIO COHTRAST DELTA E
(UC/M**2>
l.OE+02
2.0E+02
3.0E+02
1 . OE+03
2. OE+03
3. OE+03
l.OE+04
2.0E+04
3 . OE+04
1 . 0E+O3
2 . 0E+03
51 . 0E+O3
1.0E+06
2.0E+06
5 . OE+06
l.OE+07
2.0E+07
3.0K+07
1.000
1.000
1.000
.999
.099
.997
.993
.986
.967
.933
.873
.725
.500
.360
.257
.259
.281
.338
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.003
-.007
-.014
-.028
-.069
-. 133
-.247
-.493
-.709
-.845
-.870
.003
.003
.013
.025
.051
. 127
.253
.506
1.256
2.487
4.Q73
1 1 . 46O
2O.7O5
33.822
47.793
49.714
50.786
49.940
-------
BACKGROUND VISUM. RANGE (KM) 150.0
PLUME-OBSERVER DISTANCE (KID 10.00
(N02)INTEGRAL BLUE-HED RATIO CONTRAST DELTA E
(UG/H**2>
l.OE+02
2.0E+02
5.0E+02
1 . OE+03
2.0E+03
5. OE+03
1 . OE+O4
2.0E+04
5.0E+04
1 . OE+05
2. OE+03
5 . OE+03
1.0E+O6
2.0E+06
5.0E+06
1 . OE+07
2.0E+07
5. OE+07
1.000
1.000
1.000
.999
.999
.997
.995
.990
.973
.950
.905
.791
.659
.522
.443
.434
.439
.606
-.000
-.000
-.000
-.000
-.OOO
-.001
-.001
-.003
-.006
-.013
-.025
-.061
-.117
-.216
-.433
-.622
-.742
-.771
.002
.004
.010
.020
.040
. 1O1
.202
.402
.998
1.972
3.848
8.937
15.H1 4
24.844
33 . 292
36 . 09 1
08.543
38.918
-------
VISVM, RANGE c KM>
n IUSTANCE 15.0-*
(N02) INTEGRAL
< UC/M**2)
BLUE- RED RATIO CONTRAST DELTA E
] . OE+02
2 . 02+02
3 . OE+02
t . 9E+03
2.0E+03
3 . OE+03
1 . OE+04
2. OE+04
5 . OE+O4
r>o 1. OE+03
00 2.0E+05
5.0EKW
l.OE+00
2.0E*0«>
3 . OE-* 06
I . OE+07
.?. . OE+07
G.O'L+Tr
1.000
1 . 0^0
1.000
1.000
.099
.99fi
.996
.902
.981
.962
.923
. 042
. 742
. or,9
.r>r/j
.599
. 04 1
.773
- . 000
- . 00 ^
-.000
-.000
- . 000
-.001
-.001
- . 002
- . (>•)•->
-.011
- .022
- . 054
-. lOtt
-. 1<>O
-.;};;•:>
-.P47
-.(>r<>.
- . 67V
.002
. con
. coo
.016
.032
. OfiO
. K»O
.C2«
. 790
1 . r><>4
3 . 0 IP,
7.001
12.203
1 0 . 732
24 . 92 1
2O. 4 16
3 1 . 'J!(>r»
32. 190
-------
ro
BACKGROUND VISUAL RANGE (XTf) 150.0
I'LUME-OBSEIIVKR DISTANCE ( KM) 20.OO
(N02) INTEGRAL BL'^-RED IIATIO CONTIIAST DELTA E
1 . OE*32
2 . OE+O2
5 . 02+02
1 . OE+03
2.0E+03
5 . 0E+03
1 . 0E+04
2.0E+04
.*
5 . 0E+04
l.OE+05
2.0E+05
5 . 0E+05
1 . OE+06
2.0E+06
5 . 0E+06
1 . OE-S-O7
2.0K+07
5 . OS+07
1.000
l.OOO
l.OCO
1.000
.999
.999
.997
.994
.9C5
.971
. 945
.GGO
.805
.728
.6o9
.708
.753
.396
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.003
-.(MO
-.010
-.047
-.090
-. 167
-,3S4
-.430
-.572
-.594
.OO1
.OO3
. 6
.010
.026
.064
. 128
. 200
.001
t.242
2. 'MO
5.503
9 . 49O
14.333
19.464
23.2911
26.2G2
27.393
-------
BACKGROUND VISUAL RANGE (KM) 156.0
PLUriE-OBSEflVEn DISTANCE (KM) 3O.O0
(IffXSMHT&GRAL CLUE-RED RATIO CONTRAST DELTA E
(UG/H*«2)
1 . 0E+02
2.0E+02
5.9E+02
l.OE+03
2.0E+03
5.0E+03
1 . 0E+04
2.0E+04
5.0E+04
ro 1 . OE-'-OS
01 2.0E+05
5.0E+03
1.0E+Q6
2.0E+06
G.OE-i-06
1 . OE+07
2.0E+07
C . OE+07
1.000
1.000
1.000
1.000
i.oeo
.000
.993
.997
.992
.984
.969
.931
.089
. 846
.C29
. CIO
.C94
1.029
-.000
- . 000
-.009
-.000
-.000
-.000
-.001
-.002
-.004
- . 007
-.015
-.036
-.070
-. 129
-.257
-.370
-.441
-.453
.001
.002
.004
.008
.016
.041
.081
. 161
.400
.786
1 . 520
3.441
5.875
8.867
12.904
16.727
19.372
20.728
-------
BACKGROUND VISUAL RANGE (KM) 150.0
PLUME-OBSERVER DISTANCE (KM) 40.00
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
-------
ro
ftAckGRotflfD VISUAL RAkGE ckM> tse.e
PLUME-OBSERVER DISTANCE (KM) B0.ee
INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
< UG/M**2>
1.0E+02
2.0E+O2
5.0E+02
1 . 0E+03
2.0E+03
5.0E+Q3
1.0E+04
2.0E+04
5.0E-I-04
1 . 0E+03
3.0E+03
5.0E+05
1 . 0E+06
2.0E+06
3 . 0E+06
1 . OE+07
2.0E+07
5 . 0E+07
LOGO
1.000
1.C00
1.000
1.000
1.000
.999
.999
.997
.995
.990
.978
.965
.952
.953
.970
1.0T>5
1. 104
-.000
-.000
-.000
-.000
-.000
-.000
-.030
-.001
-.002
-.004
-.009
-.022
-.041
-.077
-. 133
-.220
-.262
- . 272
.000
.001
.002
.003
.007
.017
.033
.067
. 165
.323
.623
1.419
2.437
3.926
6.877
9.696
11.566
12.789
-------
BACKGROUND VISUAL RANGE (KM) 15O.0
I'LUKE-OBSERVER. DISTANCE (KM) 1O0.0
T*O2> INTEGRAL BLUE-RED KATIO CONTRAST DELTA E
(uc/ri**2>
! . 0E+02
2.0E+02
5 . 0E+02
1 . 0E+03
2.0K+03
5 . OE+03
l.OE-s-04
2 . 0S+04
5 . OE+O4
ro f . OE+05
00 2.OE+05
5 . OE+05
1 . 0E+06
2.0E+06
5 . OE+06
1 . OE+07
2 . 0E+07
a . os+'?7
1.000
1.000
1.000
1.000
1.000
LOGO
1.000
1.000
1.000
1.000
1.009
. '999
.999
.999
1.003
1.011
1.023
1.062
-.000
-.000
-.000
-.000
-.000
- . Ot>0
- . O'JO
-.O3O
-.001
-.001
-.002
-.006
-.011
-.021
-.0-ili
-.061
^-.0?2
-.075
.OOO
.OO0
.000
.001
.001
.003
. O06
.011
.023
.0.16
.111
.271
.520
.971
1 . 994
2.C33
a.!»?i
4.190
-------
BACKGROUND VISUAL RAJTGE (KM)
PLUPIE-O3SERVER DISTANCE (KM) 150.0
(N02) INTEGRAL BLUE-RED 11ATIO CONTRAST DELTA E
(UC/M**2)
l.OE-f-02
2.0E+02
0.0E+02
l.OE+03
2.0E+03
5.0E+03
1 . 0E-S-04
2.0E+04
3.0E+04
1 . 0E+03
2.0E+03
5.0E+05
1 . OE+06
2.0E+06
a . 0E+06
I . OE+07
2.0E+07
5 . 0E+07
1.3G0
1.000
1.000
1.000
1 . 000
1.000
1.000
1.000
1.000
1.000
1.009
1.000
1. 000
1.001
1.002
1.003
1.010
l.S?3
-.000
-.000
-.000
-.000
- . 030
-.000
-.000
""" • 000
""" • 000
~ * 000
-.001
-/002
-.000
-.000
-.012
-.017
-.021
-.621
.OO0
.000
.000
.000
.000
.001
.002
.003
.008
.017
.034
.083
.160
.300
.000
.GS2
1. 122
1.377
-------
BACKGROUND VISUAL RANGE (KM) 200.0
PLUMS-OllSERVER DISTANCE ( Kfl> 5.0O
S) INTEGRAL DI.rJE-I'JSD RATIO CONTRAST DELTA E
1 . OE+02
2 . OE+02
5 . 03+02
1 . 0E+03
2.0S-1-03
5.0E+G3
1 . GE+04
2.0E+04
5 . OE+04
^ 1 . OE+05
r\>
° 2 . OE+O5
0 . OE+C5
1 . OE+CO
2.0E+G6
5.0E+06
1 . OE+07
2.0E-KJ7
5 . 0E+07
1.000
l.OOO
l.CQO
.999
.999
.096
.993
.9S6
.965
.931
.069
.711
.520
.037
.219
.219
.230
.305
-.000
- . COO
-.000
-.000
-.000
-.001
-.001
-.003
-.007
-.01.1
- . 029
- . 072
-. 133
- . 255
-.509
-.732
-.873
-.907
.003
.001
.013
. 026
. 050
. 102
.264
.527
1.310
2.594
5 . 037
11.999
2 1 . 794
36 . 003
G2.093
54.287
55. 169
54. 190
-------
VISUAL BARGE zee.e
FLUTE-OBSERVER DISTANCE (KM) IO.OO
(?!02) INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1 . OE+02
2.0E+02
5 . OE+02
1 . OE+03
2. OE+03
5 . OE+03
l.OE+04
2.0E+04
3 . CE+04
£3 1 . OE+03
2.0E+03
5. OE+03
I . OE+06
2.OE+06
3 . OE+06
I . OE+07
2.0E+07
3 . 0S+07
1.000
1.000
1.000
.999
.999
.997
.994
.989
.972
.945
.393
.770
.624
.473
.384
.392
.424
.532
-.000
-.000
-.000
-.000
- . 000
-.001
-.001
- . 003
-.G07
-.013
-.027
-.063
-. 125
-.231
-.462
-.664
-.792
-.C22
.002
.004
.011
.022
.044
.110
.220
.439
1.090
2. 154
4.211
9.028
17.529
27.936
38. 112
40.945
43.563
43.771
-------
BACKGROUND VISUAL RANGE (KM) 200,0
DISTANCE (KID 13.00
(N02) INTEGRAL BLUF.-UED RATIO CONTRAST DELTA E
03
2 . OE+O3
y . OE+03
1 . 0E+04
2.0E+04
5 . 0E+04
ro 1 . OE+05
ro
^ 2.0E+05
5 . 0E+05
1 . 0E+06
2.0E+06
3 . OE+06
1 . OE+07
2.0E+07
5 . 0E+07
1.000
1.000
1.000
1.000
.999
.998
.395
.991
.973
.956
.917
.817
.701
.582
.515
.528
.568
.700
-.OOO
-.000
-.000
-.000
-.OCO
- . CO 1
-.001
-.002
-.006
-.012
-.024
-.059
-. 1 J3
-.209
-.419
-.602
-.718
-.746
.002
.004
.009
.010
.037
.092
. 103
.'J66
.907
t.790
3.490
8.076
14.2O6
22. 114
29.669
33.313
36.516
37.301
-------
BACKGROUND VISUAL RANGE CKM) 296.9
PLUME-OBSERVER DISTANCE (KID 2O.O0
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1 . OE+02
2. OE+02
3 . OE+02
1 . OE i-03
2.0E+03
5 . OE+03
1.0E+04
2.0E+04
5 . 0E+04
ro 1 . 0E+O5
ro
w 2.0E+05
5.0E+05
l.OE+06
2.0E+06
3.0E+06
1 . 0E+07
2.0E+07
5 . OE+07
1.000
1.000
1.000
1.000
.999
.998
.996
.993
.982
.965
.934
.834
.762
.668
.618
.635
.680
.024
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.002
-.006
-.011
-.022
-.053
-. 103
-. 190
-.380
-.546
-.651
-.676
.002
.003
.008
.015
.031
.076
.153
.303
.755
1.489
2.895
6.654
1 1 . 585
17.765
23.969
28. 141
31.518
32.613
-------
ro
BAflKCnOUND VISUAL RANGE (KM) 200.0
PLUME-OBSERVER DISTANCE (KM) 30.00
(NO2)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UG/M*#2>
1 . OE+02
2.0E+02
5 . OE+02
1 . 0E+03
2.0E+03
5.0E+03
1 . 02+04 ,
2.0E+04
5 . 0E+04
1 . 0E+05
2.0E+05
5 . 0E+05
1 . OE+06
2. OE+06
5 . OE+06
1.0E+07
2.0E+07
5 . 0E+O7
1.000
1.000
1.000
1.000
1.000
.999
.998
.993
.989
.978
.958
.908
.850
.792
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-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.COS
-.009
-.018
- . 044
-.083
-. !56
-.312
-.449
-.536
-.556
.001
.002
.005
.Oil
.021
.053
. 106
.212
.524
1.032
2.001
4.555
7.830
1 1 . 869
16.G36
21.355
24.601
25.931
-------
BACKGROUND VISUAL RANGE (KIT) 20O.0
PLUHE-OBSERVER DISTANCE (KM) 4O.O0
-------
ro
BACKGROUND VISUAL RANGE (KM) 2O0.0
PLUME-OBSERVER DISTANCE (KM) 5O.OO
INTEr-RAL BLUE-RED RATIO CONTRAST DELTA E
1 . OE+02
2.0E+02
5.0E+02
1 . 02+03
2.0E+03
5 . OE+03
1 . OE+04
2.0E+04
S . OE+04
1 . OE+05
2.0E+05
3 . OE+05
1 . OE+06
2.0E+06
3 . 0E+06
1 . OE+07
2.0K+07
5.0E+07
1.000
i.OOO
! . 000
1.000
1.000
1 . 000
.999
.998
.996
.991
.9R3
.964
.941
.920
.916
.906
.973
1.102
-.000
-.OOO
-.000
-.000
- . 000
-.000
-.001
-.001
- . OG3
-.006
-.012
-.039
-.057
-. 106
-.211
-.304
-.362
-.376
.001
.OO1
.003
.000
.010
.026
.052
.104
.257
.506
.978
2.216
3.815
5 . 965
9.909
13.769
16.288
!7.633
-------
DACXCROIJWD VISUAL RANGE CKPD 2OO.O
-OBSEIV/ER DISTANCE ( ICPI) IOO.0
2> INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
l.OE+02
2.0E+02
5.0E+02
1 . OE+03
2.OE+03
0. OE+03
l.OE+04
2.0E+O4
S . OE+04
IV, 1 . OE+05
ro
"^ 2. OE+05
5. OE+05
1 . OE+06
2.0E+06
0 . OE+06
1 . OE+07
2.0E+07
5. OE+07
LOGO
1.000
1.000
1.000
1 . 000
l.COO
1.000
1.000
1.000
.999
.999
.997
.995
.995
1.000
1.011
1.032
1.090
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.OOO
-.001
-.002
-.003
-.011
-.022
-.040
-.OGO
-. 114
-. 136
-. 142
.000
.000
.001
.001
.002
.006
.012
.023
.053
.114
.225
.537
1.O10
1 . C< 5
3.746
5 . S9O
C» . 528
7.370
-------
00
BACKGROUND VISUAL RANGE (KM) 2OO.O
PLUMS-OBSERVER DISTANCE (KM) 15O.O
(Nf>2) INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UGXN#«2)
1 . OE+02
2 . ©E-i-02
5.0E+O2
1 . OE+03
2.0E+03
3 . 0E+03
1.0E*04
2.0E+04
5.0E+04
1 . 0E+03
2.0E+0S
3.0E+03
1 . OE+06
2.0E+O6
5 . 0E+C6
1.0E:-07
2.0S+07
3.0E+07
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.001
1.004
1.003
l.Olfl
i . o-sa
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.004
-.oca
-.015
-.030
- . 043
-.051
-.053
.000
.000
.000
.000
.001
.002
.004
.003
.021
.042
.033
.203
.393
.736
1.491
2.134
2.610
3.045
-------
BACKGROUND VISUAL RANGE (KM) 20O.9
PLUKE-OBSERVER DISTANCE (KM) 20O.0
(H92)INTEGRAL DLUE-RED RATIO CONTRAST DELTAS
(UC/TI**2>
I . 0E+02
2.0E+02
5.0E+02
1 . 0E+03
2.0E+03
8 . 0E+03
1.0E+04
2.0E+04
5 . 0E+04
r>» 1.0E+05
ro
*° 2.0E+05
5 . 0E+03
1 . OE+06
2.0E+06
3 . 0E+06
1 . 0E+07
2.0E+07
5.0E-S-07
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.001
1.003
1.006
1.013
-.000
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-.000
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-.000
-.001
-.002
-.003
-.006
-.011
-.016
-.020
-.020
.000
.000
.000
.000
.000
.001
.002
.003
.003
.01.6
.032
.079
. 154
.207
.575
.016
.995
1. 146
-------
BACKGROUND VISUAL, RANGE (KM) 23O.0
I'LUKE-OBSERVEtt. DISTANCE (KH> 0.00
(NO2) INTEGRAL BLUE-RED RAT IO CONTRAST DF.LTA E
I . 0E+02
2.0E+02
5 . 0E+02
l.OE+03
2.0E+03
3 . OE+03
1 . OE+C4
2.0E+04
3.0E+04
ro 1 . 0E+05
0
0 2.0E+05
5 . 0E+05
1 . 0E+06
2.0E+06
5.0E+06
l.OE+07
2.0E+07
3.0E+07
1.000
1.000
1.000
.999
.999
.996
.993
.983
.964
.929
.863
.703
.314
.317
. 193
. 194
.211
.272
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.003
- . 008
-.015
-.030
-.073
-. 140
- . 260
-.319
-.747
-.890
-.924
.003
.003
.014
.027
.054
. 136
.271
.342
1.347
2.668
5.236
12.372
22.348
37.323
35 . 254
57.677
58.499
57.484
-------
BACKGROUND VISUAL RANGE fKM) 259.0
PLUKE-OBSERVEIl DISTANCE CRN) IO.O0
•fc
(H02> iHTrwnAL BLUE-RED RATIO CONTRAST DELTA E
1 . 0E+O2
2.0E+02
3 . 0E+02
1 . 0E+03
2.0E+03
5.0E+03
I.0E+04
2.0E+04
5.0E+04
i\» 1 . 0E+05
CO
""* 2.0E+05
5 . OE+05
1.0E+06
2.0E406
5.0E+06
1 . 0E+07
2.0E+07
3.OE+07
1.000
1.000
1.000
.999
.999
.997
.994
.988
.970
.942
.889
.756
.601
.441
.345
.352
.381
.482
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.003
-.007
-.014
-.028
-.063
-. 130
- . 240
-.480
-.690
-.823
-.854
.002
.005
.012
.023
.047
.116
.232
.464
1. 152
2.279
4.460
10.441
18.721
30. 137
41.743
44.645
47.390
47.501
-------
BACKGROUND VISUAL RANGE < KN) 2r.0.«
IK STANCE ( KM> i r,. 00
03
2 . OE+Q3
5 . 0E+03
1 . 03+04
2.OE+04
5 . OE+04
,vj l.OE+05
CO
1X5 2.0E+05
3 . OE+05
1 . OE+06
2.0E+06
3.0E+06
1 . OE+07
2.0E+07
5.GE+07
1.000
1.000
1 . 000
1.000
.999
.990
.995
.990
.976
.952
.909
.COO
.673
.543
.468
.400
.517
.644
-.000
- . 00',)
-.000
-.000
-.000
-.001
-.001
-.oon
-.006
-.013
-.026
-.062
-. 12O
-.222
-.443
-.630
-.761
-.790
.002
. 00.1.
.OIO
,020
.040
. 100
. 199
.397
.906
1 . 948
3.B02
0.032
15.636
24.6O1
33 . 327
37.070
40.565
41.24O
-------
BACKGROUND VISUAL RANGE (KM) 25O.O
PJLUME-OCSF.nVEn DISTANCE ( KTI> 20.00
IWTRGHAL BLUE-RED RATIO CONTRACT DELTA E
(UG/K*#2)
l.CE+02
2.0E+02
5.0E+02
1 . OE+03
2.0E+03
5.0E+03
1 . OE+04
2.0E+O4
5. OE+04
ro l.OE+05
OJ
W 2.0E+03
5.0E+05
1 . OE+06
2.0E+06
3. OE+06
l.OE+07
2.0E+07
3 . OE+07
1.000
1.000
1.000
LOGO
.999
.998
.996
.992
.930
.961
.925
.836
.733
.626
.560
.534
.627
.769
-.000
-.000
-.000
-.000
-.090
-.001
-.001
-.002
-.OOo
-.012
-.024
-.038
-. Ill
-.203
-.410
-.590
-.703
-.730
.002
.003
.009
.017
.034
.085
. 171
.340
.344
1.666
3.244
7 . 4fi9
13. 124
20 . 329
27.512
3 1 . 9O6
35.66O
36.675
-------
DACTCGROUND VISUAL IIAUGE (KM) 25
PLUME-OBSERVER DISTANCE (KM) 30.
2)INTEGRAL DLUE-RED RATIO CONTRACT DELTA E
l.OE+02
2. 02+O2
5 . OS+02
1 . OE+03
2. OE+03
5.CC-^3
1 . OE+04
2. OE+04
5 . OE+04
1 . OE+05
2.0E+05
5 . OE+05
l.OE+06
2.02+06
5.0E+06
1 . OF.+07
2 . OE+07
5.0S+07
1.000
1.000
1 . 000
1.000
.999
.999
.997
.995
.907
.974
.950
.890
.821
.751
.717
.737
.785
.939
-.OOO
- . 009
-.000
-.000
-.000
-.001
-.0»t
-.002
-.005
-.010
-.020
-.049
-.095
-. 175
- . 350
-.504
-.601
-.623
.001
.003
.006
.013
.025
.063
. 125
.250
.620
1.321
2.370
5.419
9.370
14.292
20.039
25.044
2G.737
30.091
-------
BACKGROUND VISUAL RANGE (KM) 25O.»
PLUME-OBSERVER DISTANCE (KM) 40.00
INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UG/K**2>
l.OE+02
2.0E+02
5.0E+02
l.OE+03
2.0E+03
3 . 0E+03
1.0E+04
2.0E+04
5.0E+04
ro 1.0E+05
CO
01
2.0E+05
5.0E+05
1 . OE+06
2.0E+06
5. OE+06
1.0E+07
2.0E+07
5.0E+07
1.000
1.000
1.000
1.000
1.000
.999
.990
.996
.991
.982
.966
.926
.080
.030
.017
.030
.007
1.036
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.002
-.004
-.009
-.017
-.042
-.001
-. ISO
-.299
-.430
-.513
-.032
.001
.002
.005
.009
.019
.046
.093
. 184
.457
.099
1.74O
3.95O
6.O03
10.390
15.515
20.520
23.960
25 . 343
-------
BACKGROUND VISUAL RANGE (KM) 2B0.0
PLUME-OBSERVER DISTANCE (KM) 00.00
(NO2)INTEGRAL BLUE-RED RATIO CONTRAST DKLTA R
(UC/M**2)
1.0E+02
2.0E+02
5.0E+02
1 . OE+03
2.0E+03
5.0E+03
1.0E+04
2.OE+04
5 . OE+04
ro 1 . OE+05
C*>
01 2.0E+05
5.0E+05
l.OE+06
2.0E+06
5.0E+06
l.OE+07
2.0E+07
5 . 0E+07
1.000
1.000
1.000
1.000
1.000
.999
.999
.998
.994
.988
.978
.931
.920
.891
.883
.904
.950
1.090
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.004
-.007
-.015
-.036
-.069
-. 128
-.255
-.367
-.438
-.455
.001
.001
.003
.007
.014
.034
.069
.137
.338
.465
1.287
2.922
5.028
7.793
12.514
17. 197
20.265
21.643
-------
BACKGROUND VISUAL RANGE (KM) 250.9
FLUME-OBSERVER DISTANCE (KM) 1OO.0
-------
ro
BACKGROUND VISUAL HANGL -u.l; 2r-0.0
FLUKE-OBSERVER 1HSTANCE (KM) 1T.O.O
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
1 . OE+02
2. OE+02
5 . OE+02
1 . OE+03
2. OE+03
5. OE+03
1 . OE+04
2.0E+04
5 . OE+04
1 . OE+05
2.0E+05
5. OE+05
1 . OE+06
2.0E+06
5. OE+06
l.OE+07
2.0E+07
5.0E+07
1.000
I.OOO >
1.000
1.000
1.000
l.COO
1.000
1 . 000 '
1.000
1.000
1.000
.999
.999
1.000
1.C04
1.011
1.024
1.060
-.000
-.OOO
-.000 '
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.003
-.007
-.014
-.026
-.051
-.074
-.oca
-.091
.000
.OOO
. OOO
.001
.001
.004
.007
.015
.036
.072
. 143
.349
.673
1.256
2.549
3.633
4.301
4.943
-------
VO
BACKGROUND VISUAL RANGE (KM) 250.«
PLUME-OBSERVER DISTANCE (KM) 20O.O
(N02)INTEGRAL BLUE-RED RATIO CONTRAST DELTA E
(UG/n**2>
1.0E+02
2.0E+02
5.0E+02
1 . 0E+03
2. OE+03
5 . OE+03
1 . OE+04
2.0E+04
3. OE+04
t . OE+03
2.0E+05
5 . OE+05
1 . 0E+06
2. OE+06
3 . OE+06
1 . OE+07
2. OE+07
5 . OE+07
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.002
1.003
1.010
1.023
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.001.
-.003
- . OOfi
-.011
-.022
-.032
-.030
-.039
.000
.000
.000
.000
.001
.002
.003
.006
.016
.032
.063
. 154
.298
.556
1. 115
1.576
1.095
2. 136
-------
BACKGROUND VISUAL RANGE (KM) 250.0
PLUME-OBSERVER DISTANCE ( KH> 230.0
(N02) INTEGRAL DLUE-RED R/\TIO CONTRAST DELTA E
(UO/M**2)
1 . 0E+02
2 . 0E+02
3 . 0E+02
I . OE+03
2. OE+03
5 . OE+03
1 . 0E+04
2.0E+04
5 . OE+04
1 . 0E+05
2.0E+05
5. OE+03
l.OE+06
2.0E+06
5 . OE+06
1 . OE+07
2. OE+07
5 . OE+07
1.000
1.000
1 . 000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1.000
1
1.000
1.000
.999
.999
LOGO
1.000
1.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.001
-.001
-.002
-.004
-.009
-.012
-.013
-.015
.000
.OOO
.000
.000
.000
.001
.001
,003
.007
.014
.027
.066
. 125
.220
.449
.621
.714
.746
-------
APPENDIX D
REFERENCE FIGURES AND TABLES FOR POWER PLANT VISUAL IMPACTS
This appendix presents figures and tables that show the calculated
visual impacts of emissions from power plants of various sizes under dif-
ferent meteorological and ambient conditions. These reference data are
based on calculations made using the plume visibility model (PLUVUE).
If one is evaluating a power plant (or another emissions source with
similar particulate, S02» and NOX emission rates), one can identify the
emission, meteorological, and background conditions shown here closest to
the given case under evaluation. Alternatively, one can interpolate the
values in the reference tables in this appendix to obtain a best estimate
of a source's impact. These reference tables and figures would be used in
a level-2 visibility screening analyses.
The tables and figures are based on 96 PLUVUE runs for the permuta-
tions of the following input parameters:
> Power plant size: 500, 1000, and 2000 Mwe
> Pasquill-Gifford stability category: C, D, E, F
> Wind speed: 2.5 and 5.0 m/s
> Background visual range: 20, 50, 100, and 200 km.
The emissions used in this appendix are based on emission rates of
controlled power plants meeting the EPA's New Source Performance
Standards. Emission rates of 0.03, 0.3, and 0.6 pound per million Btu
heat input—for particulates, S02, and NOX, respectively—were assumed.
The emission rates for the 1000 Mwe and 2000 Mwe plants are simple
multiples of those for the 500 Mwe case: The mass emission rates for a
500 Mwe power plant are as follows:
241
-------
1.6 tons/day
=1.5 metric tons/day
= 17 g/s
= 16 tons/day
= 14.5 metric tons/day
= 168 g/s
32 tons/day
= 29 metric tons/day
= 336 g/s.
Other important input parameters for the PLUVUE runs used to generate
the tables and figures in this appendix are summarized below:
> Particles:
> S02:
> NOX:
> Flue gas flow rate (per stack):
> Flue gas temperature:
> Ambient relative humidity:
> Background ozone concentration:
> Mixing depth:
> Simulation date/time:
> Plume-observer distance:
> Scattering angle:
> Line-of-sight orientation:
1,270,000 ft3/min
599 m3/s
175°F
353°K
40%
40 ppb
1000 m
23 September/10:00 a.m.
Maximum of 5 km or a half-sector
width (rp = 0.2 x)
90°
Horizontal, perpendicular to the
plume centerline.
As noted, if the user has a situation in which conditions are between
those used in this appendix, interpolation will yield a reasonable esti-
mate cf, impacts. However, if one has to extrapolate the results of this
appendix, one should exercise extreme caution: Many visual impacts do not
have a linear relationship with input conditions.
242
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEZD = 2.5 M/S
BACKGROUND VISUAL RANGE
PLU?IE-
DISTANCE
1.
2,
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
G03.
330.
DISTANCE
( KH)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.3
40.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(.7.)
1.3
0.3
C.5
0.4
0.
0.
0.
0.
.4
.4
,4
.5
0.5
0.3
0. 1
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.992
0.9S3
0.987
0.937
0.986
0.9C6
0.9CO
0.995
0.993
I . CCO
l.CCO
l.OCO
1 . OGO
1 . 000
i.cr.o
LOGO
PLUME
CONTRAST
AT 0.55
MICRON
-.004
-.003
-.COS
-.005
-.005
-.006
-.004
-.003
-.002
-.001
-.000
- . OGO
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A#B*)
0.52
0.72
0.77
0.78
0.81
0.63
0.61
0.33
0. 18
0.04
0.01
0.00
0.00
0.00
0.00
0.00
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
VIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DQWNWIHD
DISTANCE
(1C?!)
1.
2.
5.
10.
15.
20.
SO.
40.
50.
73.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KIP
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.8
G9.3
49.
59.
.7
,7
69.6
- 50. KM
VISUAL
RANGE
REDUCTION
1.2
0.7
0.4
0.3
0.3
C.3
0.3
0.4
0.4
0.5
0.5
0.7
0.8
0.5
0.3
0.2
BLUE-RED
RATIO
0.973
0.909
0.960
0.9C5
0.964
0.963
0.963
0.977
0.933
0.993
0.997
l.OCO
1.000
1.000
1 . COO
1.000
PLUKE PLUME
COHTR/IST PERCEPT-
AT 0.55 IBILITY
MICRON E(L*A*B*)
-.003
-.010
-.010
-.010
-.010
-.010
-.009
- . 003
.04
.41
.51
.53
.59
.62
.42
.08
-.000 0.81
-.004 0.38
-.002 0.18
-.001 0.04
-.000 0.01
-.000 0.00
-.000 0.00
-.000 0.00
243
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED -2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
130.
200.
250.
300.
350.
VISUAL RANGE
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.0
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(.7.)
1. 1
0.6
0.3
0.2
0.2
0.2
0 3
0.3
0.3
0.4
0.4
0.7
0.9
1. 1
1.2
1.4
BLUE-RED
RATIO
0.903
0.956
0.933
0.952
0.950
0.949
0.954
0.961
0.960
0.901
0.9G9
0.996
0.999
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.012
-.013
-.012
-.012
-.012
-.013
-.012
-.011
-.010
-.007
-.005
-.003
-.002
-.001
-.001
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.34
1.78
1.90
1.93
1.99
2.04
1.88
1.60
1.35
0.85
0.54
0.22
0.08
. 0.04
0.02
0.02
500NV COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =2.5 M/S
BACKGROUH
DOWNWIND
DISTANCE
(KH)
1.
2.
5.
JO.
15.
20.
CO.
<0.
50.
75.
ICO.
150.
2GO.
250.
300.
USUAL RARGE
PLUXE-
OBSERVER
DISTANCE
(KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
0.0
9.9
14.9
19.9
29.0
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RAIx?GE
REDUCTION
(5O
1.0
0.5
3.3
3.2
0.2
3.2
3.2
0.2
0.2
0.3
0.3
0.6
0.8
1.0
1.2
1.4
BLUE-RED
RATIO
0.959
0.947
0.944
0.943
0.941
0.940
0.943
0.950
0.956
0.969
0.979
0.989
0.995
0.997
0.993
0.993
PLUME
CONTRAST
AT 0.55
MICRON
-.016
-.016
-.014
-.014
-.OK-
-.014
-.014
-.013
-.012
-.010
-.008
-.600
- . 005
-.004
-.003
-.003
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.58
2.05
2. 17
2.20
2.27
2.32
2.21
1.99
1.78
1.30
0.95
0.52
O.25
0. 16
0. 12
0. 11
244
-------
500 WW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKCROlfR
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
USUAL RANGE
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(.7.)
0.7
0.5
0.3
0.2
0.2
0.2
0.2
0.3
0.3
0.3
0.2
0. 1
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.993
0.991
0.990
0.992
0.992
0.992
0.995
0.997
0.999
1.000
1.000
i.oeo
1 . 000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.003
- . 004
-.004
-.003
-.003
-.003
-.002
-.002
-.001
-.000
-.000
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.42
0.57
0.58
0.47
0.45
0.44
0.33
0. 18
0. 10
0.02
0.01
0.00
0.00
0.00
0.00
0.00
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUIE:-
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
100.
200.
250.
300.
350.
OBSERVER
DiSTAKCE
(KH)
5.0
5.
5.
5.0
5.0
5.0
.0
.0
6.0
8.0
9.9
14.9
19.9
29. S
39.3
49.
59.
.7
,7
= 50. KM
VISUAL
RAKGE
REDUCTION
(r.)
09.6
0.6
0.4
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.3
0.3
0.4
0.3
0.2
0. 1
0.0
BLUE-RED
RATIO
0.932
0.975
0.974
0.979
0.9CO
0.9CO
0.933
0.9C3
0.991
0.996
.000
.OC3
.000
.000
.000
PLUIS
CONTRAST
AT 0.55
KICROIt
-.000
- . GO?
-.007
— . 0 ~ 3
-.CC3
- . 003
-.003
- . 004
-.OC3
-.CC'2
-.001
-.OCO
- . 000
-.000
- . 000
- .ceo
PLUME
PERCEPT-
IBILITY
E( L#A#B~'
0.83
1. 11
1. 13
0.92
O.S7
O.E7
0.76
0.53
0.44
0.21
0. 11
0.02
0.01
0.00
0.00
O.CO
245
-------
509MV COAL-FIRED PLANT
PASQUILL-GIFFGRD C
WIND SPE^D =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOUNVIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
73.
ICO.
150.
200.
230.
300.
350.
cr,sEir,-En
DISTANCE
(KID
5.0
5.0
5.0
3.0
. 5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
50.7
60.6
= 100. KM
VISUAL
RANGE
REDUCTION
(8)
0.6
0.3
0.2
0.
0.
0.
0.
0.2
0.2
0.2
0.3
0.4
0.4
0.4
0.3
0.3
BLUE-RED
RATIO
0.974
0.965
0 . 964
0.971
0.973
0.973
0.975
0.979
0.9G3
0.990
0.994
0.993
0.999
1.000
1.000
1 . OCO
PLUME
CONTRAST
AT 0.55
MICRON
-.003
-.009
-.009
-.007
-.007
-.007
-.006
-.006
-.003
-.004
-.003
-.002
-.001
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
.06
.40
.42
. 15
.09
.09
.00
0.86
0.73
0.48
0.31
0. 11
0.05
0.03
0.01
0.01
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED = 5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOttNWIND
DISTANCE
(101)
1.
2.
H!
10.
13.
21.
30.
40.
50.
75.
100.
150.
200.
230.
SCO.
330.
OBSERVER
DISTANCE
(ED
5.0
5.
5.
.0
.0
o.O
5.0
5.0
6.C
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(55)
0.5
0.3
0
0
0
0
0
0
0
0
0.2
0.3
9.3
0.3
0.3
0.3
RLUE-RED
RATIO
0.963
C.SC3
0.9G3
0.966
0.963
O.OC3
0.970
0.973
0.976
0.9C3
0.9C3
0.994
0.997
0.993
0.999
0.999
PLUME
CONTRAST
AT 0.55
MICRON
-.011
-.011
-.010
-.003
-.003
-.CC3
, -.007
-.007
-.007
-.006
-.003
-.003
-.002
-.002
- . 00 1
-.001
FLUTE
PERCEPT-
IBILITY
E(L*A*B*)
.23
.61
.62
.31
,24
.24
.17
.07
0.96
0.73
0.55
0.27
0. 16
0. 10
0.07
0.05
246
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED = 2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
130.
200.
250.
300.
350.
'ISUAL RANGE = 2O. KM
PLUME-
OBSERVER
DISTANCE
(KT-i)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
VISUAL
RAKGE
REDUCTION
(JJ)
1.6
1.3
1.0
0.9
0.8
0.8
0.7
0.7
0.7
0.6
0.3
0.0
0.0
0.0
0.0
0.0
ELITE- RED
RATIO
0.990
0.9S7
0.9G2
0.978
0.976
0.977
0.985
0.993
0.997
.030
.000
.OCO
.000
.000
.OCO
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.005
-.006
-.008
-.009
-.010
-.009
-.007
- . 004
-.003
-.C01
-.000
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.63
0.78
1. 10
1.35
1.41
1.39
0.95
0.48
0.25
0.05
0.02
0.00
0.00
0.00
0.00
0.00
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEZD =2.5 M/S
BACKGROUK
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
f ISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(*>
1.5
1.2
0.9
0.7
0.6
0.6
0.5
0.5
0.5
0.6
0.6
0.7
0.7
0.5
0.2
0.1
BLUE-RED
RATIO
0.973
0.966
0.952
0.941
0.933
0.939
0.951
0.967
0.977
0.990
0.996
0.999
1.000
1.000
1.000
1.000
FLUME
CONTRAST
AT 0.55
MICRON
-.010
-.011
-.014
-.017
-.018
-.017
-.014
-.011
-.009
-.005
-.003
-.001
-.001
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E
-------
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED - 2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOVNVIHD
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KFD
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
20.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(JO
1.3
1. 1
0.7
0.6
0.5
0.4
0.4
0.4
0.4
0.4
0.5
0.6
0.7
0.9
1. 1
1.5
BLUE-RED
RATIO
0.961
0.952
0.932
0.918
0.914
0.915
0.920
0.944
0.956
0.974
0.9B4
0.994
0.998
0.999
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.014
-.015
-.019
-.021
-.022
-.022
-.019
-.016
-.014
-.010
-.007
-.005
-.003
-.002
-.001
-.001
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.61
1.97
2.74
3.34
3.51
3.43
2.93
2.35
1.91
1.20
0.77
0.35
0. 17
0.08
0.04
0.02
500MW COAL-FIRED PLANT
PASOUILL-GIFFOrJ) D
WIND SPE2D =2.5 M/S
BACKGROUND VISUAL RANGE
PLUI1E-
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
SCO.
350.
OE3OVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
<9.7
59.7
69.6
= 200. KM
VISUAL
RA:
-------
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED * 5.0 M/S
BACKGROUND
DOWN WIVD
DISTAN:E
(KM)
i.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE = 20 . KM
PLUHE-
ODSERVER
DISTANCE
(Hi)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
VISUAL
RANCE
REDUCTION
(.7.)
1.2
0.9
0.6
0.5
0.5
0.4
0.4
0.4
0.4
0.3
0.2
0.0
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.994
0.991
0.987
0.934
0.935
0.936
0.991
0.996
0.993
.000
.GOO
.000
.000
.000
.000
.000
PLUKE
CONTRAST
AT 0.55
MICRON
-.003
-.004
-.oor»
-.006
-.006
-.006
-.004
-.002
-.001
-.000
-.000
-.coo
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.37
0.53
0.81
0.95
0.91
0.83
0.53
0.26
0. 13
0.03
0.01
0.00
0.00
0.00
0.00
0.00
500NW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =8.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWINI)
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
200.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5
.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.
59.
.7
,7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
( ?•)
1. 1
0.8
0.5
0.4
0.3
0.3
0.3
0.3
0.3
0.3
0.3
0.4
0.4
0.2
0. 1
0.0
PLUrE PLUME
BLUE-RED
RATIO
0.934
0.977
0.964
0.938
0.960
0.963
0.973
0.932
0.933
0.995
0.990
1.000
1.000
l.OCO
1.000
1.000
CONTRAST
AT 0.55
MICRON
-.006
-.007
-.010
-.012
-.011
-.010
-.003
-.000
-,CC5
-.003
-.002
-.001
-.000
-.000
-.000
-.000
PERCEPT-
IBILITY
E(L*A*B*)
0.74
.04
.59
.85
.78
.63
.23
0.84
0.59
0.26
0. 12
0.03
0.01
0.00
0.00
0.00
249
-------
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD D
VIND SPEED =5.0 M/S
BACKGROUND
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
2CO.
250.
300.
350.
'ISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(7.)
1. 1
0.7
0.4
0.3
0.3
0.2
0.2
0.2
0.2
0.2
0.3
0.4
0.4
0.4
0.3
0.3
BLUE-RED
RATIO
0.977
0.967
0.930
0.942
0.944
0.949
0.960
0.970
0.977
0.987
0.993
0.990
0.999
1.000
1.000
1.000
PLUHE
CONTRAST
AT 0.55
MICRON
-.010
-.010
-.013
-.015
-.014
-.013
-.010
-.008
-.CG7
-.005
-.003
-.002
-.001
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
0.97
1.33
2.00
2.33
2.23
2.05
1.63
1.25
0.98
0.58
0.36
0. 13
0.05
0.03
0.01
0.01
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWIND
DISTANCE
(KID
1.
2.
5.
10.
15.
20.
SO.
40.
50.
75.
100.
150.
.200.
250.
303.
3GQ.
OBSERVER
DISTANCE
( ED
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(%)
1.0
0.6
0.4
0.3
0.2
0,2
0.2
0.2
0.2
0.2
0.2
0.3
0.3
0.3
0.3
0.3
BLUE-RED
RATIO
0.970
0.960
0.941
0.931
0.934
0.9G9
0.951
0.961
0.963
0.979
0.986
0.993
0.997
0.993
0.999
0.999
PLUME
CONTRAST
AT 0.55
MICRON
-.014
-.013
-.016
-.017
-.016
-.014
-.012
-.010
-.009
-.007
-.000
- . C04
-.003
-.002
-.001
-.001
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
1. 16
1.54
2.29
2.66
2.55
2.34
1.91
1.55
1.29
0.88
0.63
0.32
0. 17
0. 11
0.07
0.05
250
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED = 2.5 M/S
BACKGROUND VISUAL RANGE
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
2CO.
230.
300.
330.
PLUIE-
OESERVIR
DISTANCE
(IGI)
5.0
5.0
5.0
5.0
5.0
.0
.0
8.0
9.9
14.9
19.9
29.3
39.8
49.7
59.7
69.6
5,
6.
20. KM
VISUAL
RANGE
REDUCTION
(%)
2.9
2.2
1.5
1.3
1.2
1.2
1.2
1.3
1.3
1.2
0.6
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.939
0.937
0.931
0.976
0.972
0.970
0.977
0.933
0.994
0.999
l.OCO
1.000
l.OCO
1.070
J .000
1.000
PLWE
CONTRAST
AT 0.53
MICROK
-.006
-.COO
_ /"* n"*
~ . V/vvj
-.010
-.012
-.012
-.011
- . COS
~.C03
- . C 02
-.001
*~ » C v>3
~~ . C C ?*
-.CGO
-.GOO
-.OCO
PLUME
PERCEPT-
IBILITY
E(L*A«B#)
0.74
0.35
1. 14
1.47
1.67
1.30
1.45
0.31
0.44
0. 10
0.03
0.00
o.co
o.co
o.co
0.00
500 WW COAL-FIRED PLANT
PASQJILL-GIFFORD E
WIND SPEED =2.5 H/S
BACKGROUIiD VISUAL RANGE =
50. KM
DOWNWIND
DISTANCE
(KJ!)
1.
2.
s!
10.
13.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
PLUTE-
OESERVER
DISTANCE
< KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.3
39.8
49.7
59.7
69.6
VISUAL
R' :
-------
500 WW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =2.5 K/S
BACKGROUND VISUAL RANGE = 100. KM
DOTvNWIND
DISTANCE
( 13!)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
130.
200.
230.
300.
330.
PLUKE-
OBSERVER
DISTANCE
( KH)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
69.6
VISUAL
RINGE
REDUCTION
(V.)
2.5
1.8
1.2
0.9
0.8
0.8
0.7
0.7
0.3
0.3
0.9
1. 1
1.2
1.3
1.5
1.8
BLUE-RED
RATIO
0.954
0.940
0.930
0.910
0.893
0.890
0.892
0.907
0.922
0.933
0.972
0.99-0
0.900
0.9';9
1.0 JO
1. COO
PLUME
CONTRAST
AT 0.55
MICRON
-.020
-.019
-.021
-.023
-.027
-.029
-.030
-.027
-.025
-.019
-.014
-.003
_ /x/Nrt
• \- \j O
-.003
-.002
-.001
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.97
2. 19
2.83
3.63
4. 17
4.50
4.52
3.97
3.39
2.20
1.40
0.62
0.29
0.16
0.03
0.05
500MW COAL-FIRED PLANT
PASCUILL-GIFFGFJO E
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
= 200. KM
DOWNWIND
DISTANCE
( 12!)
I.
2.
•3 .
j ->
i o
1.6
1. 1
0.3
0.7
0.6
0.6
0.6
0.6
0.6
0.7
0.9
1.0
1.2
1.3
1.7
BLUE-RED
RATIO
0.940
0.933
0.914
0.392
0.879
0.870
C-.S37
0.379
0.892
0.922
0.946
0.971
0.9G4
0.990
0.994
0.997
PLUME
CONTRAST
AT 0.55
MICRON
-.030
-.027
-.027
-.030
-.032
-.034
-.033
-.033
-.031
-.026
-.021
-.016
-.012
-.010
-.COG
-.006
PLUMS
PERCEPT-
IBILITY
E(L*A*B*:
2.33
2.39
3O'^
• \^\^
4.23
4.79
5. 16
5.32
4.96
4.50
3.37
2.43
1 .46
0.90
0.61
0.40
0.26
252
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KID
1.
2.
5.
10.
15.
20
30.
40.
50.
75.
ICO.
150.
200.
250.
300.
350.
rISUAL RANGE
PLUMI:-
OBSERVER
DISTANCE
( KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
6.0
9.9
14.9
19.9
29. G
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
( %>
1.7
1.2
0.9
0.7
0.7
0.7
0.7
0.7
0.7
0.7
0.3
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.994
0.992
0 . 9S7
0.9C2
0.9CO
0.9CO
0.930
0.993
0.997
1.000
1.000
.000
.000
.ceo
.000
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.003
- . 004
-.000
-.007
-.003
-.003
-.007
-.C04
- . 003
-.001
-.000
-.000
-.000
- . 000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L#A*B*>
0.42
0.52
0.81
1.06
1. 18
1.23
0.91
0.48
0.25
0.06
0.01
0.00
0.00
0.00
0.00
0.00
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUME—
DOWNWIND *~
DISTANCE
1.
2.
5.
10.
15.
20.
SO.
40.
50.
75.
1CO-.
1GO.
200.
2CO.
300.
350.
OESER^R
DISTANCE
(KM)
5.0
5,
5,
5.0
5.0
.0
.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RAI.GE
REDUCTION
( 7i)
1.6
J. 1
0.7
C.6
0.5
0.5
0.5
0.5
0.5
0.6
0.6
0.6
0.6
0.3
0. 1
0.0
BLUE-RED
RATIO
0.932
0.977
0.904
0.933
0.9-13
0.9-16
0.93-i
0.907
0.977
0.990
0.996
0.999
l.COO
1 . OCO
1.000
l.OGO
PLUME
CONTRAST
AT 0.55
MICRON
-.003
-.003
-.011
-.013
-.015
-.015
-.014
-.011
-.009
-.005
-.003
-.001
-.000
-.000
-.OCO
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.86
1.04
1.59
2.08
2.33
2.41
2. 10
1.56
1. 15
0.54
0.26
0.06
0.02
0.01
0.00
0.00
253
-------
500MW COAL-FIRED PLANT
P4SQUILL-GIFFORD E
WIND SPEED = 5.0 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
ICO.
150.
20D.
250.
300.
330.
OBSERV1
D I STAIN
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
-------
500MV COAL-FIRED PLANT
PASQUILL-CIFFORD F
KIND SPEED =2.5 M/S
BACKGRQUW
DOWNWIND
DISTANCE
(01)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100. ,
150.
200.
250.
300.
350.
,'ISUAL RANGE
PLUME-
OBSERVER
DISTANCE
( ETI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
a.o
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(7.)
3.9
3. 1
2.4
2.0
1.8
1.8
1.8
1.9
2.0
2.2
1. 1
0.3
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.9C6
0.9S3
0.979
0.974
0.970
0.967
0.974
0.9G6
0.993
0.999
1.000
1.000
1.000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.008
-.009
-.010
-.012
-.013
-.014
-.013
-.010
-.C07
-.003
-.001
-.000
-.000
-.000
-.eco
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.94
. 10
.35
.62
.83
.99
.68
.00
0.59
0. 16
0.05
0.01
0.00
0.00
0.00
0.00
500MW COAL-FIRED PLANT
PASQUILL-G1FFORD F
VIND SPE!T,!> =2.5 M/S
BACKGROUW
DOWNWIND
DISTANCE
(EM)
1.
2.
5.
10.
10.
20.
30.
1-0.
50.
75.
100.
150.
2CC.
250.
SOO.
3GO. 69.6
USUAL RANGE = 50. KM
PLUl'SL-
OB3SRVER
DISTANCE
(KT!)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
VISUAL
RA::GE
REDUCTION
(J
?>
3.6
2.9
2. 1
.7
.5
.5
.4
.5
.6
.8
2.0
2.2
2.3
1
.2
0. 1
0.0
BLUE-RSD
RATIO
0.961
0.953
0.942
0.930
0.920
0.913
0.915
0.932
0.946
0.973
0.9G7
0.990
1.000
1.000
1.000
1.000
pLurar,
CONTRAST
AT 0.55
MICRON
-.018
-.018
-.020
-.022
-.025
-.020
-.027
-.025
-.023
-.017
-.012
-.005
-.002
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.92
2.21
2.68
3.21
3.62
3.96
3.94
3.31
2.71
1.56
0.87
0.28
0. 10
0.05
0.02
0.01
255
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 2.5 M/S
BACKGROUND VISUAL RANGE
FLUKE-
DOWNWIND
DISTANCE
(KM)
1.
o>
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KTI)
5.0
5
5
5.0
5.0
.0
.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
( 7?)
3.4
2.7
.9
.5
.3
.3
.2
.2
.3
.4
.6
.9
2. 1
2.3
2.5
2.8
BLUE-RED
RATIO
* 0.942
0.932
0.917
0.901
0.889
0.879
0.874
0.835
0.897
0.926
0.930
0.978
0.951
0.997
0.999
1.000
FLUME
CONTRAST
AT 0.55
MICRON
-.027
-.026
-.027
-.029
-.032
-.034
-.036
-.036
-.035
-.031
-.026
-.010
-.012
- . 000
-.005
-.003
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
2.53
2.86
3.43
4.08
4.60
5.02
5.30
4.99
4.59
3.51
2.57
1.32
0.69
0.38
0.22
0. 14
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =2.5 M/S
BACKGROUND V!
DOWNWIND
DISTANCE
(KM)
1.
2.
s!
10.
ID.
20.
CO.
40.
50.
75.
ICO.
150.
200.
250.
3CO.
350.
ISUAL RANGE = 200. KM
PLUKE-
OBSERVER
DISTANCE
(EM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
VISUAL
RANGE
REDUCTION
(Jt)
3.1
2.4
.7
.3
.2
. 1
.0
.0
.0
. 1
.2
.5
.7
.9
2.1
2.5
BLUE-RED
RATIO
0.923
0.913
0.893
0.880
0.866
0.855
0.845
0.849
0.855
0.873
0.902
0.940
0.964
0.978
0.927
0.902
PLUME
CONTRAST
AT 0.55
MICRON
-.039
-.036
-.035
-.036
-.039
- . C4 1
-.043
-.044
-.045
-.043
- . 040
-.C33
-.027
-.022
-.01B
-.015
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
3.06
3.40
4.00
4.72
5.31
5.78
6.27
6.27
6. 12
5.41
4.58
3. 12
2. 11
1.45
1.01
0.72
256
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =5.0 M/S
BACKGROUN
D0l.1l WIND
DIST/AUCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
4SUAL RANGE = 20. KM
PLUME- VISUAL
OBSERVER RANGE
DISTANCE REDUCTION
(KM) (%)
5.0 2.3
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
.7
.2
. 1
.0
.0
.0
. 1
. 1
.2
19.9 0.6
29.8 0.0
39.8 0.0
49 . 7 0.0
59.7 0.0
69.6 0.0
BLUE- RED
RATIO
0.993
0.992
0.983
0.9E3
0.9GO
0.978
0.9S2
0.990
0.993
0.999
1.090
1.000
1.000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.004
- . 004
-.005
-.007
-.008
-.009
-.009
-.006
-.004
-.002
-.001
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B#)
0.47
0.54
0.76
1.03
1.21
1.35
1. 15
0.68
0.39
0. 10
0.03
0.00
0.00
0.00
0.00
0.00
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWIND
DISTANCE
<'KH)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5
5
.0
.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
2.1
1.6
1. 1
0.9
0.8
0.8
0.8
0.8
0.9
1.9
1. 1
1.2
1.2
0.6
0.0
0.0
BLUE-RED .
RATIO
0.981
0.977
0.967
0.955
0.947
0.941
0.942
0.953
0.964
0.983
0.992
0.999
1.000
LOGO
1.000
l.OCO
PLUME
COfiTRAST
AT 0.55
MICRON
-.009
-.009
-.011
-.014
-.016
-.017
-.018
-.016
-.014
-.010
-.007
-.003
-.001
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B#)
0.97
1.09
1.50
2.03
2.39
2.66
2.67
2.22
1.78
0.97
0.52
0. 15
0.05
0.02
0.01
0.01
257
-------
500MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 5.0 M/S
BACKGROUND VISUAL RANGE
PLUME-
iVNVIND
STANCE
( 131)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5-0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(f.)
2.0
1.5
1.0
0.8
0.7
0.7
0.6
0.7
0.7
0.8
0.9
1.0
1.1
1. 1
1.2
1.2
BLUE-RED
RATIO
0.971
0.966
0.953
0.937
0.926
0.918
0.914
0.922
0.931
0.953
0.970
0.9C8
0.995
0.998
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.015
-.014
-.015
-.018
-.020
-.022
-.024
-.023
-.022
-.018
-.015
-.010
-.006
- . 004
-.003
-.002
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.28
1.41
1.91
2.57
3.02
3.35
3.57
3.32
2.99
2. 17
1.53
0.75
0.37
0.20
e. 11
0.07
500MV COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =5.0 M/S
BACKCROUN
DO^WIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REACTION
(%)
1.8
1.3
0.9
0.7
0.6
0.6
0.5
0.5
0.5
0.6
0.6
0.8
0.9
1.0
1.0
1.1
BLUE-RED
RATIO
0.960
0.957
0.943
0.924
0.911
0.902
0.894
0.898
0.904
0.924
0.941
0.965
0.980
0.988
0 . 993
0.996
PLUME
CONTRAST
AT 0.55
MICRON
-.022
-.019
-.019
-.022
-.024
-.026
-.023
-.028
-.028
-.025
-.023
-.018
-.014
-.011
-.009
-.007
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.58
1.69
2.21
2.95
3.46
3.84
4.21
4. 15
3.96
3.32
2.70
1.75
1.14
0.75
0.51
0.36
258
-------
1800MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED = 2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
-(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350. 69.6
'ISUAL RANGE
FtUNE-
OE3ERVER
DISTANCE
(ICM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
= 20. KM
VISUAL
RANGE
REDUCTION
(J?)
2.4
1.5
0.8
0.7
0.7
0.8
0.8
0.9
0.9
0.8
0.5
0.2
0. 1
e.o
0.0
0.0
BLUE-RED
RATIO
0.990
e.98G
0.935
0.981
0.978
0.976
0.982
0.991
0.996
0.999
1.000
1.090
1.000
1.000
1.000
i.eco
PLUME
CONTRAST
AT 0.55
MICRON
-.005
-.006
-.006
-.008
-.009
-.010
-.008
-.006
-.004
-.001
-.000
-.OCO
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.66
0.86
0.94
1. 12
1.33
1.45
1.12
0.62
0.34
0.08
0.02
0.00
0.00
0.00
0.00
e.oo
COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =2.5 K/S
BACKGROUN
DOWNWIND
DISTANCE
(131)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
2CO.
300.
350.
VISUAL RANGE
PLUT2-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(JO
2.3
1.3
0.7
0.5
0.5
0.6
0.6
0.7
0.7
0.8
0.9
1. 1
1.0
0.7
0.5
0.3
BLUE-RED
RATIO
0.973
0.963
0.959
0.950
0.941
0.936
0.943
0.957
0.969
0.986
0 . 994
0.999
1.000
1.000
1.000
1.000
PLUHE
CONTRAST
AT 0.55
MICRON
-.012
-.012
-.012
-.014
-.017
-.018
-.017
-.015
-.012
-.008
-.005
-.002
-.001
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
1.32
1.71
1.84
2.21
2.61
2.86
2.60
2.03
1.55
0.77
0.38
0.11
0.04
0.02
0.01
0.00
259
-------
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
( EM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
OBSERV
DISTANi
(KT!)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(%)
2. I
1.2
0.6
0.4
0.4
0.4
0.5
0.5
0.6
0.7
0.7
1.0
1.2
1.4
1.7
2.2
BLUE-RED
RATIO
0.960
0.947
0.942
0.931
0.919
0.911
0.916
0.928
0.940
0.963
0.977
0.991
0.997
0.999
1.000
1.000
PLUHE
CONTRAST
AT 0.55
MICRON
-.018
-.017
-.016
-.018
-.021
-.022
-.022
-.021
-.019
-.014
-.011
-.007
-.004
-.003
-.002
-.001
PLUME
PERCEPT-
IBILITY
E
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUT!E-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
OBSERVER
DISTANCE
(HI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
6.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(X)
1.3
0.8
0.5
0.4
0.4
0.4
0.4
0.5
0.5
0.3
0.1
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.992
0.989
0.9C5
0.9G6
0.926
0.9C6
0.990
0.995
0.993
l.OCO
1.600
l.OCO
l.OCO
1.000
l.OCO
i.eco
PLUKE
CONTRAST
AT 0.55
MICRON
- . 004
-.005
-.006
-.006
-.006
- . 006
-.005
-.003
-.002
-.001
-.000
-.000
-.000
-.000
-.ceo
-.coo
PLUME
PERCEPT-
IBILITY
E(L*A#B*)
0.50
0.70
0.88
0.84
0.83
0.85
0.64
0.35
0. 19
0.05
0.01
0.00
0.00
0.00
0.00
0.00
1800NW COAL-FIRED PLANT
FASQUILL-GIFFOIID C
VIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUIIE-
OD3ERVER
DISTANCE
( KM)
DISTANCE
i ia-1)
i.
2.
5.
10.
15.
20.
SO.
40.
50.
73.
100.
150.
200.
aco.
300.
330.
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
K.9
19.9
29.3
39.0
49.7
59.7
69.6
= 50. 101
VISUAL
RAKGE
REDUCTION
(!?)
1.2
0.7
0.4
0.3
0.3
0.3
0.3
0.4
0.4
0.5
0.5
0.6
0.5
0.4
0.2
0.1
BLUE-RED
RATIO
0.979
0.969
0.961
0.963
6.963
0 . 902
0.967
0.976
0.9C2
0.992
0.906
0.909
i.eoo
l.OCO
1 . 000
1.000
PLUKE PLDTE
CONTRAST PERCEPT-
AT 0.55 IBILITY
MICRON E(L*A*B*>
-.003 0.99
- . 009
-.011
-.010
-.010
-.010
-.010
-.003
.37
.73
.64
.62
.66
.47
. 14
-.007 0.80
-.004 0.45
-.003 0.23
-.001 O.C6
-.000 0.02
-.000 0.01
-.000 0.00
-.000 0.00
261
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFOHD C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWIND
DISTANCE
• KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
ICO.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RARGE
REDUCTION
(.%)
1. 1
0.6
0.3
0.2
0.2
0.2
0.2
0.3
0.3
0.4
0.4
0.5
0.6
0.7
0.7
0.6
BLUE-RED
RATIO
0.969
0.957
0.946
0.948
0.949
0.948
0.952
0.959
0.966
0.970
0.937
0.995
0.990
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.012
-.012
-.014
-.013
-.013
-.013
-.012
-.011
-.010
-.003
-.006
-.004
-.002
-.001
-.001
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.28
1.73
2. 18
2.06
2.04
2.08
1.95
1.7O
1.46
0.99
0.67
0.29
0. 12
0.05
0.03
0.02
1600MW COAL-FIRED PLANT
PjSSQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUEE-
DOWNWIND
DISTANCE
(KTD
1.
2.
5.
10.
15,
20.
30.
4-0.
50.
75.
100.
150,
200.
250.
300.
350.
OBSEHY5A
DISTANCE
(KM)
5.0
5.
5.
5.0
5.0
5.0
.0
.0
6.0
S.O
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(/?)
1.0
0.6
0.3
0.2
0.2
0.2
0.2
0.2
0.2
0.3
0.3
0.5
0.5
0.6
0.6
6.6
BLUE- RED
RVTIO
0.961
0.940
0.935
0.939
0.940
0.939
0.941
0.947
0.952
0.964
0.974
0.986
0.993
0.996
0.993
0.999
PLUME
CONTRAST
AT 0.55
MICRON
-.016
-.015
-.016
-.015
-.014
-.015
-.014
-.014
-,C13
-.011
-.010
-.007
-.COS
-.004
-.003
-.002
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
1.51
2.00
2.49
2.35
2.32
2.37
2.29
2. 11
1.93
1.51
1.18
0.68
0.39
0.22
0. 14
0. 10
262
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED = 2.5 MXS
BACKGROUND
DOWNWIND
DISTANCE
(KM)
i.
2.
5.
10.
15.
JO.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RAN(E
PLUME-
OBSERVER
DISTANCE
( KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(%)
3.0
2.5
1.8
1.5
.4
.3
.3
.3
.3
. 1
0.6
0. 1
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.980
0.985
0.970
0.971
0.968
0.967
0.976
0.9SO
0.994
0.999
.080
.ceo
.000
.000
.000
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.006
-.007
-.010
-.012
-.014
-.014
-.012
-.003
-.005
-.002
-.001
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.79
0.97
1.38
1.77
1.95
2.03
1.52
0.82
0.44
0. 10
0.03
0.00
0.00
0.00
0.00
0.00
1000NV COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =2.5 M/S
BACKGROUR
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE = 50. KM
FLUKE- VISUAL
OBSERVER RANGE
DISTANCE REDUCTION
(KM) (?J)
5.0 2.8
5.0 2.2
5.0 1.6
5.0 1.2
5.0
5.0
6.0 (
8.0 (
9.9
14.9
19.9
29.8
39.8
. 1
.0
).9
).9
.0
.0
. 1
.2
. 1
49.7 0.7
59.7 0.3
69.6 0.1
BLUE-RED
RATIO
0.967
0.959
0.940
0.923
0.915
0.911
0.923
0.944
0.959
0.932
0.992
0.999
1.000
1.090
1.000
1.000
PLUKE
CONTRAST
AT 0.55
MICRON
-.014
-.015
-.019
-.023
-.025
-.026
-.024
-.020
-.016
-.010
-.006
-.003
-.001
-.001
-.©GO
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.59
1.93
2.74
3.51
3.87
4.02
3.56
2.68
2.02
1.00
0.51
0.15
0.05
0.02
0.01
0.00
263
-------
1090MW COAL-FIRED PLANT
PASttUILL-GIFFORD D
WIND SPEED =2.5 M/S
BACKGROUND Vi
DOVNW1ND
DISTANCE
(KM)
I.
2.
5.
10.
15.
20.
GO.
40.
50.
75.
100.
150.
200.
250.
300.
350.
rISUAL RANGE
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
B.O
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(7.)
2.6
2.1
1.4
1. 1
0.9
0.8
0.7
0.7
0.7
0.8
0.8
1.0
1.2
1.3
1.5
1.7
BLUE-RED
RATIO
0.951
0.941
0.915
0.892
0.881
0.877
0.88C
0.906
0.922
0.952
0.970
0.988
0.995
0.998
1.060
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.022
-.022
-.026
-.030
-.032
-.033
-.031
-.028
-.025
-.019
-.014
-.009
- . 006
-.004
-.003
-.002
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
2.09
2.49
3.48
4.44
4.90
5.09
4.77
4.03
3.40
2.25
1.49
0.73
0.37
0.20
0. 11
0.07
1000MW COAL-FIRED PLANT
PA5QU1LL-GIFFORD D
VI ID SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
OBSERVER
DISTANCE
-------
1000MV COAL-FIRED PLANT
PASQUILL-CIFFORD D
WIND SPEED =3.0 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
ISO.
200.
250.
300.
330.
VISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(%)
2.4
1.6
1.1
0.9
0.8
0.8
0.7
0.7
0.7
0.6
0.3
o.o
0.0
0.0
O.O
0.0
BLUE- RED
RATIO
0.993
0.990
0.983
0.978
0.976
0.976
0.904
0.993
0.997
.000
.000
.000
.000
.000
.000
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.004
-.005
-.007
-.009
-.010
-.010
-.007
-.004
-.003
-.001
-.000
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.49
0.64
1.02
1.32
1.42
1.42
0.98
0.49
0.25
0.05
0.01
0.00
0.00
0.00
0.00
0.00
1000NW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLOTS-
DOWNWIND
DISTANCE
(Ell)
1.
2.
5.
10.
15.
20.
30.
•50.
50.
73.
103.
150.
200.
250.
300.
350.
OSSEPJ'TR
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
e 50. KM
VISUAL
RANGE
REDUCTION
(%)
2.3
1.5
0.9
0.7
0.6
0.6
0.5
0.5
0.5
0.5
0.6
0.6
0.5
0.3
0. 1
0.0
BLUE- RED
P.ATIO
0.960
0.973
0.935
0.942
0.937
0.937
0.950
0.966
0.977
0.990
0.996
0.999
1.030
1.000
1.030
1.000
PLUKE
CONTRAST
AT 0.55
MICRON
-.010
-.010
-.014
-.017
-.018
-.018
-.015
-.012
-.009
-.005
-.003
-.001
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.00
1.28
2.01
2.59
2.80
2.80
2.27
1.60
1. 15
0.53
0.26
0.06
0.02
0.01
0.00
0.00
265
-------
10O0MV COAL-FIRED PLANT
PASQUILL-GIFFORD D
V1ND SPEED = 5.0 M/S
BACKGROUN
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350. 69.6
VISUAL RANGE
PLUME-
OBSERVER
DISTANCE
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
= 100. KM
VISUAL
RANGE
REDUCTION
(%)
2. 1
1.3
0.8
0.6
0.5
0.5
0.4
0.4
0.4
0.4
0.5
0.5
0.6
0.6
0.6
0.6
BLUE-RED
RATIO
0.970
0.961
0.937
0.919
0.913
0.913
0.926
0.943
0.955
0.974
0.985
0.995
0.998
0.999
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.016
-.015
-.018
-.021
-.022
-.022
-.019
-.016
-.014
-.010
-.007
-.004
-.002
-.001
-.001
-.000
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
1.33
1.64
2.54
3.27
3.54
3.52
3,02
2.40
1.93
1. 18
0,75
0,31
0.14
0.06
0.03
0.02
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED = 5.0 M/S
BACKGROUND V
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
2GO.
300.
350. 69.6
'ISUAL RANGE
PLUKE-
033ERVER
DISTANCE
(ED
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
= 200. KM
VISUAL
RANGE
REDUCTION
(J5>
1.9
1.2
0.7
0.5
0.4
0.4
0.3
0.3
0.3
0.3
0.4
0.4
0.5
0.5
0.6
0.6
BLUE-RED
RATIO
0.959
0.950
0.924
0.904
0.897
0.897
0.910
0.92C
0.938
0.953
0.970
0.985
0.992
0.996
0.99Q
0.999
PLUME
CONTRAST
AT 0.55
MICRON
-.023
-.020
-.022
-.025
-.026
-.025
-.023
-.020
-.017
-.014
-.011
-.003
-.006
- . 004
-.003
-.002
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
1.64
1.94
2.93
3.75
4.04
4.03
3.55
2.98
2.54
1.79
1.33
0.74
0.43
0.25
0.15
0. 10
266
-------
COAL-FIRED PLANT
PASQUILL-CIFFORD E
WIND SPEED =2.5 M/S
BACKGROUN!) VISUAL RANGE
FLUKE-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
2 GO.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.
5,
.0
.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.0
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
5.7
4.3
3.0
2.4
2.2
2. 1
2. I
2.2
2.3
2.2
1. 1
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.983
0.970
0.972
0.966
0.962
0.959
0.967
0.933
0.991
0.999
l.COO
.OCO
.000
.OCO
.OCO
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.010
-.011
-.013
-.015
-.017
-.010
-.017
-.012
-.008
-.OC3
-.001
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
1. 18
1.43
1.75
2.09
2.35
2.54
2.09
1.22
0.70
0. 18
0.05
0.01
0.00
0.00
0.00
0.00
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
( KM)
1.
*>,
5\
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(JO
5.3
3.9
2.6
2.0
1.8
1.7
1.6
1.7
1.8
1.9
1.9
2.1
2.1
1.2
0.3
0.0
BLUE-RED
RATIO
0.952
0.940
0.925
0.909
0.893
0 . 890
0.895
e.9i7
0.937
0.970
0.987
0.990
1.000
1.000
l.OGO
1.000
PLUIIE
CONTRAST
AT 0.55
MICRON
-.023
-.024
-.026
-.029
-.032
-.034
-.034
-.031
-.027
-.010
-.011
-.005
-.002
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
2.41
2.88
3.48
4.16
4.67
5.05
4.93
4.03
3.20
1.69
0.86
0.25
0.09
0.04
0.02
0.01
267
-------
1000WW COAL-FIRED PLANT
PASCUILL-GIFFORD E
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
FLUKE-
DOWNWIND
DISTANCE
< KM)
1.
2 .
H!
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
ORSERV1
DISTANi
(KM)
5,0
5.0
5.0
5.0
5..0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(5?)
5.0
3.6
2.4
1.8
1.6
1.4
1.3
1.4
1.4
1.5
1.6
1.0
2.0
2.3
2.4
2.7
BLUE-RED
RATIO
0.928
0.912
0.894
0.873
0.858
0.847
0.844
0.860
0.879
0.920
0.950
0.9SO
0.992
0.997
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.036
-.035
-.035
-.033
-.041
-.043
-.045
-.044
-.041
-.033
-.026
-.016
-.010
-.007
-.004
-.003
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
3.20
3.74
4.46
5.30
5.94
6.43
6.64
6. 10
5.44
3.81
2.54
1.22
0.60
0.32
0. 18
6. 11
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLU1E-
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
SCO.
350.
OBSERVER
DISTANCE
(KTD
5.0
5
.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(%)
4.5
3.3
2.1
1.6
1.4
.2
. 1
. 1
. 1
. 2
.2
1.4
1.7
2.0
2.2
2.4
BLUE- RED
RATIO
0.902
0.8SO
0.869
0 . 847
0.830
0.817
0.809
0.817
0.830
0.863
0.903
0.944
0.968
0.981
0.9G9
0.993
PLUME
CONTRAST
AT 0.55
MICRON
-.053
-.043
-.045
-.0-15
-.049
-.051
-.054
-.054
-.C53
- . 047
-.040
-.031
-.024
-.019
-.015
-.012
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
3.93
4.46
5.20
6. 13
6.C6
7.41
7.88
7.68
7.26
5.88
4.53
2.87
1.84
1.23
0.84
0.59
268
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWN WIND OBSERVER
DISTANCE DISTANCE
(El)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
1.
2.
5.
10.
15.
29.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(JO
3.4
2.3
.6
.3
.2
.2
.2
.2
.3
.2
0.6
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.991
0.989
0.983
0.977
0.973
0.971
0.977
0.9C8
0.994
0.999
1.000
l.OCO
1.000
l.OCO
l.OCO
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.006
-.006
-.007
-.010
-.011
-.012
-.011
-.008
-.005
-.OG2
-.001
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.64
0.74
.03
.39
.61
.76
.43
0.81
0.45
0.10
0.03
0.00
0.00
0.00
0.00
0.00
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOVNWIND
DISTANCE
( EM)
1.
2.
3.
10.
i;».
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.
5.
5.0
5.0
.0
.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(H)
3.2
2.1
1.4
1. 1
1.0
0.9
0.9
0.9
.0
.0
.0
.1
.0
0.5
0.1
0.0
BLUE-RED
RATIO
0.974
0.969
0.955
0.939
0.929
0.923
0.927
0.945
0.959
0.932
0.992
0.999
1.000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.013
-.012
-.015
-.018
-.021
-.023
-.023
-.020
-.016
-.010
-.006
-.002
-.001
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
1.32
1.47
2.05
2.75
3.19
3.43
3.35
2.64
2.03
1.01
0.50
0.13
0.04
0.01
0.01
0.00
269
-------
1000WW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED = 5.0 V/S
BACKGROUfi
DOKNVIflD
DISTANCE
(EH)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
VISUAL RANGE = 100. KM
PLUME-
OBSERVER
DISTANCE
(KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
40-7
59.7
69.6
VISUAL
liARGE
REDUCTION
(55)
3.0
2.0
1.2
0.9
0.3
0.8
0.7
0.7
0.8
0.8
0.8
0.9
0.9
0.9
0.9
0.9
BLUE- RED
RATIO
0.961
0.955
0.937
0.915
0.902
0.893
0.892
0.907
0.922
0.952
0.971
0.990
0.997
0.999
1.000
1 .000
PLUME
CONTRAST
AT 0.55
MICRON
-.021
-.018
-.020
- . 024
-.026
-.023
-.029
-.027
-.025
-.019
-.014
-.003
- . 004
-.003
-.001
-.001
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
1.76
1.92
2.60
3.48
4.03
4.41
4.48
3.97
3.42
2.26
1.47
0.62
0.27
0.12
0.06
0.03
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
.'50.
I'GO.
150.
; oo.
i 30.
OBSERVER
DISTANCE
(HI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(.?.)
2.7
1.8
1. 1
0.8
0.7
0.6
0.6
0.6
0.6
0.6
0.6
0.7
0.0
0.3
0.8
0.3
BLUE-RED
RATIO
0 . 945
0.941
0.922
0.893
0.S33
0.872
0.868
0.879
0.891
0.920
0.943
0.971
0.935
0.993
0.996
0.993
PLUME
CONTRAST
AT 0.55
MICRON
-.031
-.026
-.025
-.029
-.031
-.033
-.035
-.033
-.032
-.026
-.022
-.015
-.011
-.007
-.005
— />** /»
. \f\JV
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
2. 19
2.29
3.02
4.00
4.63
5.05
5.28
4.96
4.53
3.46
2.60
1.46
0.82
0.48
0.28
0. 17
270
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 2.5 tl/S
BACKGROUH
DOWNWIND
DISTANCE
(EH)
i i:
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE
PLU?ZE-
OBSERVER
DISTANCE
(HI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(T.)
7.7
6.4
4.8
3.9
3.6
3.4
3.3
3.5
3.6
3.3
1.3
0.0
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.973
0.963
0.959
0.935
0.952
0.949
0. >61
6.979
0.990
0.999
.OCO
.eoo
.OCO
.OCO
.OCO
.000
PLUME
CONTRAST
AT 0.55
MICRON
-.014
-.017
-.020
-.021
-.022
-.023
-.021
-.015
-.011
-.005
-.002
-.eoo
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B#)
1.57
2. 15
2.63
2.84
3.00
3. 16
2.57
1.50
0.88
0.25
0.09
0.01
0.00
0.00
0.00
0.00
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUIIE-
DOWNWIND OBSERVER
DISTANCE DISTANCE
(CM) (KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
COO.
350.
5.
5.
5.0
5.0
,0
,0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
7.3
5.9
4.3
3.4
3.0
2.8
2.7
2.8
2.9
3.2
3.5
3.9
4.2
1.9
0. 1
0.0
BLUE-RED
RATIO
0.936
0.910
0.823
0.878
0.871
O.SoS
O.S72
0.899
0.922
0.9SO
0.931
0.996
1.000
1. 000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.031
-.036
-.C40
-.041
- . 043
-.044
-.044
-.040
-.036
-.027
-.019
-.COS
- . 004
-.002
-.001
-.COO
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
3.22
4.34
5.29
5.70
6.02
6.34
6.09
5.00
4.05
2.34
1.33
0.46
0. 19
0.09
0.04
0.02
271
-------
1000MW COUL-FIRED PLANT
PASQUILL-'JIFFORD F
VIND SPEED = 2.5 M/S
BACKGROUND VISUAL RANGE
PLUNE-
DOVNWIHD
DISTANCE
(OD
1.
2.
5.
10.
15.
.20.
30.
40.
50.
75.
100.
150.
200.
250.
SCO.
350.
OBSERVER
DISTANCE
(E-I)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
B.O
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
6.3
5.4
3.9
3.0
2.7
2.5
2.3
2.3
2.4
2.6
2.9
3.4
3.7
4.0
4.2
4.5
BLUE-RED
RATIO
0.904
0.859
0.841
0.329
0.820
0.810
0.810
0.829
0.343
0.391
0.925
0.966
0.986
0.995
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.048
-.052
-.054
-.054
-.056
-.057
-.059
-.C5S
-.056
-.030
-.043
-.031
-.021
-.010
-.010
-.007
PLUME
PERCEPT-
IBILITY
E(L*A#B*)
4.29
5.66
6.81
7.31
7.72
8. 12
8.26
7.62
6.94
5.32
3.96
2. 14
1.17
0.68
0.42
0.28
1000MW COAL-FIRED PLANT
PASQ-UILL-CIFFORD F
WIND SPEED = 2.5 M/S
BACKGROUK
DOWNWIHI)
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
SO.
40.
50.
75.
100.
150.
200.
250.
300.
350. 69.6
1SUAL RANGE
FLUKE-
OBSERVER
DISTANCE
( KH)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
= 200. KM
VISUAL
RAKGE
REDUCTION
(?J)
6.2
4.9
3.5
2.7
2.4
2.2
2.0
2.0
2.0
2. 1
2.2
2.6
3.0
3.3
3.6
4.0
BLUE- RED
RATIO
0.871
0.333
0.804
0.792
0.7S2
0.772
0.763
0.775
0.737
0.820
0.852
0.905
0.941
0.964
0.979
0.937
PLUME
CONTRAST
AT 0.55
MICRON
-.070
-.071
-.069
-.067
— . C6S
-.069
-.072
-.072
-.072
-.070
-.067
-.038
-.049
-.041
- . 034
-.028
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
5.27
6.75
7.98
8.51
8.96
9.42
9.85
9.66
9.34
8.30
7. 14
5. 08
3.56
2.52
1.82
1.35
272
-------
1000MV COAL-FIRED PLANT
PASQUILL-GIFFORD F
VIND SPEED =5.0 M/S
BACKGROUW "'
DOVNWIRD
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
fISUAL RANGE
PLUKE-
OB5TRVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
(JO
4.5
3.4
2.4
1.9
1.8
1.7
1.3
1.9
2.0
2. 1
1. 1
0.0
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.990
0.987
0.982
0.977
0.973
0.970
0.975
0.937
0.993
0.999
l.OCO
1 . 000
l.OCO1
1 . OCO
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.00?
-.007
-.008
-.010
-.012
-.013
-.012
-.009
-.007
-.003
-.001
-.CCO
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
0.76
0.90
1.12
1.41
1.65
1.83
1.58
0.96
0.57
0.16
0.05
0.01
0.00
0.00
0.00
0.00
1000NW COAL-FIRED PLANT
TASQUILL-GIFFORD F
WIND SPEED =5.0 ll'S
BACKGROUND VISUAL RANGE
PLOTS-
DO WIWIRD
DISTANCE
(EM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
( KM)
5.0
5.0
5.0
5.0
5.0
5.6
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.
59.
,7
,7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(3)
4.2
3. 1
2. 1
7
5
4
4
5
6
3
9
2. 1
2.2
1. 1
0. 1
0.0
BLUE-RED
RATIO
0.970
0.9C3
0.952
0.939
0.923
0.920
0.920
0.935
0.943
0.973
0.9S7
0.993
1.000
1.000
1.000
LOGO
PLUKS
CONTRAST
AT 0.55
MICRON
-.016
-.016
-.017
-.020
-.022
-.024
-.026
-.024
-.022
-.016
-.012
-.005
-.002
-.001
-.000
-.000
PLUME
PERCEPT-
IBILITY
1.57
1.81
2.23
2.79
3.26
3.63
3.71
3. 16
2.62
1.53
O.S3
0.23
0. 10
0.05
0.02
0.01
273
-------
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =5.0 H/S
BACKGROUND VISUAL RANGE
PLUKE-
DOVNWIND
DISTANCE
( ED
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
2G3.
250.
SCO.
350.
OBSERVER
DISTANCE
( E3-D
5.0
5.
5.
5.0
5.0
.0
.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.0
49.7
59.7
69.6
= 100. KM
VISUAL
RA?:C E
REDUCTION
4.0
2.9
2.0
.5
.3
_ o
'.2
.2
.3
.4
.6
.3
.9
2.0
2. 1
2. 1
BLUE-RED
RATIO
0.953
0.945
0.931
0.914
0.9CO
0.8S3
0.331
0.890
0.900
0.927
0.930
0.973
0.991
0.997
0.999
LOGO
PLUME
CONTRAST
AT 0.55
MICRON
-.026
-.024
-.024
-.026
-.029
-.032
-.034
-.034
-.034
-.030
-.026
-.018
-,0!2
-.003
-.003
-.003
PLUME
PERCEPT-
IBILITY
E(L*A#B*)
2. 12
2.33
2.86
3.56
4. 14
4.61
4.98
4.77
4.44
3.45
2.55
1.33
0.69
0.33
0.22
0. 14
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 5.0 M/S
BACKGROUND VISUAL RAICGE
PLOTS-
OBSERVER
DISTANCE
(EH)
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
ICO.
2CO.
230.
300.
330.
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
!9.9
29.3
39.8
49.
59.
,7
,7
69.6
= 230. KM
VISUAL
RANGE
REDUCTION
tr.)
3.5
2.6
.7
.3
.2
. 1
.0
.0
.0
. 1
.2
.4
.5
.7
.3
.9
BLUE-RED
RATIO
0.934
0.927
0.914
0.395
0.879
0.336
0.834
G.335
0.860
0.830
0.9C3
0.940
0.964
0.979
0.923
0.993
PLUMS
CONTRAST
AT 0.55
MICRON
-.040
-.035
-.032
-.033
-.036
-.033
-.041
-.043
-.043
- . 042
-.040
-.033
-.027
-.022
-.017
-.014
PLBKE
PERCEPT-
IBILITY
E(L*A#B#>
2.66
2.87
3.36
4. 12
4.78
5.31
5.90
5.99
5.91
5.32
4.54
3.13
2. 11
1.43
0.99
0.71
274
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEZD = 2.5 tt/S
BACKGROUND VISUAL RAKGE
PLUKE-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
CEJI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
69.6
* 20. KM
VISUAL
RATGE
REDUCTION
(T.)
4.8
2.3
.4
.2
.3
.4
.5
.6
.7
.5
0.9
0.3
0. 1
0.0
0.0
0.0
BLUE- RED
RATIO
0.938
C.933
0.932
0.977
0.970
0.965
0.972
0 . 935
0.993
0.999
l.COO
l.COO
1.000
l.CCO
LOGO
l.COO
PLUKE
CONTRAST
AT 0.55
MICRON
-.003
-.003
-.003
-.010
-.012
-.015
-.014
-.010
-.CO?
-.003
- . 00 1
-.000
-.COO
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A#B»)
0.88
1. 10
1. 12
1.39
1.80
2.14
1.77
1.04
0.59
0. 15
0.04
0.01
0.00
0.00
0.00
0.00
1000MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =2.5 II/S
BACKGROUND VISUAL RANGE
PLWIE-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
4-0.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
( KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
3.0
9.9
14.9
19.9
29.3
3'5.3
<9.7
50.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
4.5
2.6
1.2
1.0
1.0
1.0
1.1
1.2
1.3
1.5
6
1.9
1.7
1. 1
0.6
O.-i
1
BLUE-RED
RATIO
Q.9S4
0.930
0.951
0.939
0.92!
0 . 907
0.910
0.929
0.946
0.975
0.9C9
0.993
1 . OGO
1.000
l.COO
LOGO
PLUKE
CONTRAST
AT 0.55
MICRON
-.013
-.013
-.015
-.013
-.023
-.C27
-.023
-.026
-.022
-.015
-.009
-.C04
-.002
-.001
-.000
- . coo
PLUTE
PERCEPT-
IBILITY
E(L*A#B*)
1.81
2.20
2.21
2.73
3.56
4.23
4. 16
3.41
2.70
1.41
0.72
0.22
0.03
0.04
0.02
0.01
275
-------
2000MW COAL-FIRED PLANT
PASQUILL-G1FFORD C
WIND SPEED = 2.5 M/S
BACKGROUND VISUAL RANGE
PLUM-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERY1
DISTAKC
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.0
39.3
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDT'CTIOH
(5J)
4.2
2.4
1. 1
0.3
0.8
0.8
0.9
1.0
1.0
1.2
1.3
1.6
1.9
2. 1
2.4
2.6
BLUE-RED
RATIO
0.946
0.932
0.931
0.915
0.891
0.871
0.867
0.331
0.897
0.933
0.9G8
0.932
0.903
0.997
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.029
-.025
-.020
-.023
-.029
-.034
-.037
-.036
-.034
-.C27
-.021
-.014
-.020
-.000
-.004
-.003
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
2.43
2.84
2.81
3.46
4.50
5.36
5.58
5.14
4.56
3.16
2. 12
1.07
0.55
0.31
0. 18
0. 11
2000NW COAL-FIRED PLANT
PASQUILL-GIFFO^D C
WIND SPEZD = 2.5 M/S
BACKGROUU
DOWNWIND
DISTANCE
(KID
1.
2.
5.
10.
15.
20.
30.
40.
30.
75.
100.
150.
200.
2~0.
300.
330.
VISUAL RAKGE
PLUKE-
OBSERVER
DISTANCE
( KK)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(.7.)
3.9
2. 1
1.0
0.7
0.7
0.7
0.7
0.8
0.8
0.9
1.0
1.3
1.6
1.3
2. 1
2.5
BLUE-RED
RATIO
0.925
0.914
0.917
0.899
0.870
0 . 8-iO
0.3C3
0.345
O.S56
O.S90
0.910
O.')51
0.970
0.9C2
0.950
0.994
PLUME
CONTRAST
AT 0.55
MICRON
- . 043
-.034
-.025
-.023
- . 034
- . 0-iO
-.043
-.044
-.043
-.038
-.033
-.027
-.022
-.013
-.015
-.012
PLUME
PERCEPT-
IBILITY
E(L*A#B#)
3.02
3.36
3.24
3.97
5. 16
6. 15
6.59
6.45
6.07
4.86
3.77
2.52
1.70
1. 19
0.80
0.56
276
-------
20000MW COAL-FIRED PLAN
PASQUILL-GIFFORD C
WIND SPEED =5.0 MXS
BACKGROUND VISUAL RANGE = 20
DOWNWIND
DISTANCE
(KM)
1.
. o
«M .
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
VISUAL
RANGE
REDUCTION
(%)
2.6
1.5
0.9
0.8
0.8
0.8
0.8
0.9
1.0
0.9
0.5
0.2
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.991
0.937
0.981
0.979
0.977
0.976
0.922
C.991
0.995
0.999
1.000
l.CCO
1.000
1.000
1.0CO
I.OCO
pLurx
CONTRAST
AT 0.55
Micnori
-.005
-.COG
-.008
-.CCS
-.009
-.010
-.009
-.005
- . 004
-.001
-.001
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
0.61
0.82
1. 17
1.27
1.36
1.46
1. 14
0.64
0.36
0.09
0.03
0.00
0.00
O.CO
0.00
0.00
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKGROUN
DOWNWIND
DISTANCE
(Ml)
1.
2.
5.
10.
15.
20.
SO.
40.
50.
75.
100.
150.
200.
250.
GOO.
350.
flSVAL RANGE
PLUHE-
OBSERVER
DISTANCE
( KID
5.0
5.0
5.0
5.0
5.0
5.0
6.0
C.O
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(5?)
2.4
1.3
0.7
0.6
0.6
0.6
0.6
0.7
0.7
0.9
0.9
1.0
0.9
0.5
0.3
0.2
BLUE-RED
RATIO
0.975
0.965
0.949
0.944
0.940
0.9C3
0.942
0.9TC
0.967
0.935
0.993
0.999
1.000
1.000
LOGO
LOGO
PLUI-E
CONTR/JST
AT 0.55
MICRCn
-.012
-.012
-.015
-.016
-.017
-.010
-.010
-.015
-.013
-.009
-.C06
-.002
-.001
-. GOG
-.000
-.000
PLOTS
PERCEPT-
IBILITY
1.24
1.62
2.30
2.50
2.69
2.G3
2.65
2. 30
1.64
0.86
0.45
0. 12
0.04
O.C2
0.01
0.00
277
-------
2000MV COAL-FIRED PLANT
PASQUILL-GIFFORD C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKS-
DOWNWIND
DISTANCE
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
2GO.
300.
350.
OBSERV1
DISTANi
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
- 100. KM
VISUAL
RAKGE
REDUCTION
(7.)
2.3
1.2
0.6
0.5
0.4
0.4
0.5
0.5
0.6
0.7
0.3
0.9
1.0
J.O
1. 1
1. 1
BLUE- RED
RATIO
0.962
0.950
0.929
0.922
0.917
0.911
0.914
0.926
0.937
0.959
0.974
0.990
0.99G
0.999
1.000
1. 000
PLUME
CONTRAST
AT 0.55
MICRON
-.018
-.017
-.019
-.020
-.021
-.023
-.023
-.021
-.020
-.016
-.013
-.003
-.005
-.003
-.002
-.001
PLUKE
PERCEPT-
IBILITY
E(L*A*B*)
1.64
2.07
2.90
3. 15
3.38
3.63
3.53
3. 14
2.75
1.91
1.31
0.60
0.28
0. 14
0.07
0.04
2000TTW COAL-FIRED PLANT
PASQUILL-GIFFOPJ) C
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RAKGE
PLUKE-
DOWNVIND
DISTANCE
1 .
5!
10.
15.
20.
30.
40.
5C.
75.
IOC'.
150.
200.
25G.
300.
350.
OBSERVER
DISTANCE
(KJ!)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
59
.7
.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(JO
2.0
1. 1
0.5
0.4
0.4
0.4
0.4
0.4
0.4
0.5
0.6
0.7
0.3
0.9
1.0
1 .0
BLUE-RED
RATIO
0.949
0.930
0.915
0.908
0.901
0.894
0.895
0.903
0.912
0.932
0.949
0.972
0.935
0.992
0.995
0.993
PLUP32
CONTRAST
AT 0.55
MICF-OH
-.026
-.022
-.022
-.023
-.024
-.026
-.026
- . 026
-.025
-.022
-.020
-.015
-.011
-.COG
-.006
-.005
PLUME
PERCEPT-
IBILITY
E( L*A#B#:
1.99
2.41
3.32
3.60
3.87
4. 15
4. 15
3.92
3.64
2.93
2.32
1.42
0.87
0.53
0.33
0.21
278
-------
2000KW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KI'D
i.
2.
i!
10.
15.
20.
30.
40.
50.
75.
ICO.
150.
200.
230.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.
5.
5.0
5.0
.0
,0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.8
49.7
59.7
69.6
= 20. KI1
VISUAL
RANGE
REDUCTION
6.0
4.3
3.5
2.3
2.4
2.3
2. 1
2.2
2. 2
2.0
1. 1
0. 1
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
G.926
0.920
0.971
0.963
0.939
0.937
0.963
0.92-1
0.992
0.909
l.OCO
1.000
1.009
l.CCD
1.0C3
1.003
PLOT-IE
CONTRAST
AT 0.55
MICRON
-.009
-.011
-.014
-.017
-.013
-.019
-.016
-.011
-.CCS
-.003
-.C01
-.000
-.000
-.oco
-.CGO
- . eco
PLUME
PERCEPT-
IBILITY
E(L*A#3*)
1.06
1.35
1.34
2.33
2.54
2.63
2.07
1. 17
0.66
0.17
0.05
0.01
0.00
O.CO
0.00
0.00
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(Kii)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
OBSERVER
DISTANCE
2. 18
2.72
3.69
4.65
5.07
5.25
4.88
3.87
3.04
1.64
0.87
0.23
0. 10
0.05
0.02
0.01
279
-------
2000NW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KM)
1.
o
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
WSTANCE
(KM)
5.0
5.
5.
5.0
5.0
5.0
.0
.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49
59.
.7
.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(7J)
5.3
4. 1
2.8
2.1
1.7
1.5
1.4
1.3
1.4
1.5
1.6
1.8
2.0
2.2
2.4
2.6
BLUE-RED
RATIO
0.933
0.917
0.8S3
0.859
0.847
0.841
0.846
0.866
0.834
0.922
0.949
0.978
0.991
0.997
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.035
-.035
-.033
-.042
-.044
-.045
-.045
-.042
-.039
-.033
-.026
-.013
-.012
-.OOG
-.005
- . 004
PLUME
PERCEPT-
IBILITY
E(L*A*B»)
2.93
3.57
4.73
5.93
6.46
6.69
6.57
5.85
5.17
3.70
2.58
1.33
0.70
0.40
0.23
0. 15
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
VIND SPEED =2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
25C.
3CO.
35C.
rISUAL RANGE
PLUNE-
OB5ERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(7.)
4.8
3.7
2.5
.8
.5
.3
. 1
. 1
. 1
.1
.2
.4
.6
.9
2.1
2.3
BLUE-RED
RATIO
0.910
0.892
0.861
0.829
0.816
0.810
0.311
0.824
0.838
0.872
0.901
0.939
0.963
0.97G
0 . 9G7
0.992
PLUKE
CONTRAST
AT 0.55
MICRON
-.053
-.030
-.049
-.052
-.053
-.053
-.053
-.052
-.050
-.045
-.040
-.033
-.027
-.023
-.010
-.015
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
3.65
4.29
5.53
6.87
7.45
7.71
7.79
7.36
6.69
5.72
4.61
3.14
2.13
1.50
1.04
0.74
280
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
VIND SPZED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
SCO.
350.
OBSERV
D1STAI*
(KH)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
S.O
9.9
14.9
19.9
29.8
30.0
49.7
59.7
69.6
= 20. KM
VISUAL
RAKGE
REDUCTIOIJ
(J?)
4.3
3. 1
2.0
1.6
1.4
.3
.3
.3
.3
. 1
0.0
0.1
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.991
0.9C7
0.9CO
0 . 972
0.963
0.966
0.973
0.903
0.994
0.909
1. 000
l.OCO
1.000
l.CGO
LOGO
l.COO
PLUME
CONTRAST
AT 0.55
MICRON
-.007
-.007
- . 009
-.012
-.014
-.014
-.012
-.OC3
-.003
-.002
-.001
-.000
-,oco
-.ceo
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A#B#)
0.70
0.87
1.27
1.71
1.95
2.03
1.60
0.86
0.45
0. 10
0.03
0.00
0.00
0.00
0.00
0.00
2000NW COAL-FIRED PLANT
PASQUILL-GIFF07.D D
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE =
50. KM
DOVNUIKD
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
PO.
40 .
50 '.
75.
100.
150.
200.
230.
300.
330.
PLUKZ- VISU/i
OESIRVER RAKGE
DISTANCE REDUCTION
( KID ( r. )
5.0 4.5
5.0 29.,
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
7
3
1
.0
.0
.0
.0
.0
.0
. 1
39. S 0.9
49.7 C.5
59.7 0.2
69.6 0.1
BLUE-RED
RATIO
0.973
0.964
0 . 943
0.923
0.915
0.9C9
0.919
0.941
0.933
0.922
0.992
0.999
1.000
l.OCO
1 . 000
1.000
PLUPE
CONTRAST
AT 0.55
MICRON
-.016
-.015
-.0}G
-.023
-.C23
-.027
-.025
-.021
-.017
-.010
-.006
-.002
-.00!
-.000
-.000
-.000
PLUKE
PERCEPT-
IBILITY
E( L*A#B*>
1.45
1.75
2.53
3.33
3.86
4. 12
3.74
2. SO
2.07
0.99
0.49
0.13
0.04
0.02
0.01
0.00
281
-------
2000NW COAL-FIRED PLANT
PASQUILL-CIFFORD D
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
3CO.
350.
OBSERV:
DISTAI><
( on
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDICTION
(.7.)
4.2
2.7
1.6
1. 1
0.9
0.8
0.8
0.7
0.8
3.8
0.8
0.9
0.9
1.0
1.0
1.0
BLUE-RED
RATIO
0.957
0.947
0.922
0.896
0 . 802
0.&74
O.ESO
0.902
0.920
0.952
0.971
0.939
0.996
0.999
LOGO
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.026
-.023
-.025
-.029
-.022
-.034
-.033
-.029
-.025
-.019
-.014
-.003
-.005
-.003
-.002
-.001
PLUKS
PERCEPT-
IBILITY
E(L*A*B-~O
1.99
2.29
3.22
4.29
4.83
5.21
5.00
4.21
3.49
2.22
1.45
0.64
0.30
0. 14
0.03
0.04
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD D
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
DOWNWJND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
2CO.
230.
300.
350.
OBSERVER
DISTANCE
(KH>
5.0
5
.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
69.6
= 200. KM
VISUAL
RAKGE
REDUCTION
(%)
3.9
2.4
1.4
1.0
0.8
0.7
0.6
0.6
0.6
0.6
0.6
0.7
0.3
0.8
0.9
0.9
BLUE-RED
RATIO
0.939
0.930
0.904
0.875
0 . 839
0.850
0 . 854
0.372
0.839
0.922
0.944
0.970
0.924
0.991
0.995
0.997
PLUKS
CONTRAST
AT 0.55
MICRON
-.040
-.033
-.031
-.C33
- . 033
-.039
- . CSS
-.C33
-.032
-.026
-.022
-.016
-.011
-.003
-.005
-.005
PLOTS
PERCEPT-
IBILITY
E(L*A*E#)
2.53
2.75
3.74
4.94
5.60
5.90
5.90
5.26
4.63
3.40
2.57
1.51
0.91
0.56
0.35
0.23
282
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
13.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.
.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
( 5O
11.4
8.3
6. 1
4.8
4.3
4.0
3.9
3.9
4.0
3.9
1.9
0.0
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.975
0.959
0.950
0.946
0 . 9-1-3
0.940
0.954
0.976
0.9C3
0.993
1.0C3
1.000
l.COO
l.CSO
1.0CO
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.017
-.023
-.023
-.026
-.027
-.029
-.026
-.CIS
-.013
-.003
-.C02
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.85
2.76
3.25
3.44
3.62
3.80
3.05
1.76
1.02
0.28
0.09
0.01
0.00
0.00
0.00
o.eo
2000MV COAL-FIRED PLANT
PASQUILL-GIFFORD E
VIND SPEZD =2.5 M/S
BACKGROUU
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
SO!
40.
50.
70.
100.
150.
2CO.
230.
300.
330.
'ISUAL RANGE
PLUT25-
O3SERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
0.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(J?)
10.3
8.1
5.4
4.1
3.6
3.3
3. 1
3.2
3.2
3.4
3.5
3.3
3.6
1.9
0.5
0.0
BLUE-RED
RATIO
0.926
O.S23
0.862
0.834
O.SvO
O.S33
0 . S-19
O.SS2
0.910
0.956
0.9GO
0.996
1.000
LOGO
1.003
1.000
PLOTS
COIiTRAST
AT 0.55
MICRON
-.039
- . 047
-.030
- . 030
-.032
- . 034
- . 054
- . 043
-.042
-.030
- . 020
-.009
- . 004
-.002
-.001
-.000
PLOTID
PERCEPT-
IBILITY
E(L*A*B#)
3.84
5.61
6.53
6.94
7.32
7.63
7.23
5.83
4.69
2.58
1.33
0.44
0. 17
0.03
0.04
0.02
283
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEEO =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
- 100. KM
VISUAL
RANGE
REDUCTION
( %)
10.2
7.5
5.0
3.7
3.2
2.9
2.6
2.6
2.6
2.8
2.9
3.3
3.5
3.3
4.0
4.4
BLUE-RED
RATIO
0.837
0.833
0.803
0.794
0.7D4
0.774
0.776
0.801
0.826
0.331
0.922
0.967
0.9S7
0.995
0.999
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.061
-.068
-.068
-.067
-.063
-.070
-.071
-.063
-.065
-.055
-.044
-.030
-.020
-.013
-.009
-.006
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
5. 19
7.35
8.51
8.93
9.41
9.87
9.91
9.01
8.07
5.87
4.09
2.08
1.09
0.62
0.36
0.23
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =2.5 M/S
BACKGROUK
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
'ISUAL RANGE
PLUME-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(R)
9.4
6.9
4.4
3.2
2.3
2.5
2.2
2.1
2. 1
2.2
2.2
2.6
2.9
3.2
3.5
3.9
BLUE-RED
RATIO
0.844
0.787
0.759
0.750
0.739
0.723
C.723
0.738
0.755
0.802
0.847
0.903
0.945
0.967
0.931
0.989
PLUME
CONTRAST
AT 0.55
MICRON
-.092
-.093
-.037
-.032
-.032
-.034
-.036
-.035
-.G33
-.077
-.069
-.C56
-.0-55
-.037
-.030
- . 02-1
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
6.48
8.79
10.00
10.42
10.94
11.47
11.66
11.45
10.89
9.18
7.39
4.93
3.30
2.31
1.59
1. 14
284
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
BACKGROUN
DOW? WIND
DISTANCE
(KM)
I.
2.
5.
10.
13.
20.
30.
40.
50.
7">.
10 >.
150.
20J.
2GO.
300.
350.
MSUAL RANGE
PLUTIE-
OE3ERVER
DISTANCE
(KTI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
<%)
6.8
4.6
3.0
2.4
2.2
2. 1
2. 1
2.2
2. 2
2.2
1. 1
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.937
0.902
0.977
0.970
0.965
0.961
0.969
0.9G3
0.992
0.999
l.OCO
1.000
l.OGO
1 . 000
1.000
l.OCO
PLUKE
CONTRAST
AT 0.55
MICRON
-.009
-.010
-.011
-.013
-.015
-.017
-.016
-.011-
-.003
-.003
-.001
-.000
- . CCO
-.COO
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
1.02
1.22
1.49
1.87
2. 16
2.38
2.00
1.18
0.68
0. 18
0.05
0.01
0.00
0.00
0.00
0.00
2000MV COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED =5.0 M/S
EACKGROUH
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
230.
300.
350.
'ISUAL RANGE = 50. KM
PLUKE- VISUAL
OBSERVER R^NGE
DISTANCE REDUCTION
(131) '.7.)
5.0 6.5
5.0 4.3
5.0 2.7
5.0 2.1
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
.8
.7
.6
.7
.8
.9
.9
.9
.?
49.7 0.9
59.7 0.2
69.6 0.0
BLUE-RED
RATIO
0.960
0.949
0.936
0.919
0.906
0.897
0.899
0.920
0.938
0.970
0.987
0.998
1.000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
HICROH
-.023
-.022
-.022
— . C2o
-.G29
-.C32
-.C33
- . 030
-.027
-.018
-.012
-.003
-.002
-.001
-.000
-.000
PLUKE
PERCEPT-
IBILITY
2. 11
2.47
2.97
3.72
4.30
4.73
4.72
3.91
3.13
1.69
0.87
0.24
0.03
0.03
0.01
0.01
285
-------
2000MW COAL-FIRED PLANT
PASQUILL-G1FFORD E
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOVNWIND OBSERVER
DISTANCE DISTANCE
(K?l> (KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
5.
5.
5,
5
5.0
5.0
.0
.0
.0
.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 10«. KM
VISUAL
RANGE
REDUCTION
(7.)
6. 1
4.0
2.5
1.8
1.6
1.4
.3
.4
1.4
1.5
1.6
1.6
1.6
1.6
1.6
1.5
BLUE-RED
RATIO
0.938
0.925
0.909
0.836
0.869
0.856
0.851
0.865
0.8Q1
0.920
0.949
0.981
0.993
0.993
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICP.ON
-.037
-.033
-.031
-.034
-.033
-.041
-.C43
- . 042
- . 040
-.033
-.026
-.016
-.009
-.COS
-.003
-.002
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
2.88
3.24
3.81
4.74
5.47
6.02
6.35
5,91
5.32
3.80
2.59
1.17
0.53
0.25
0.13
0.07
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD E
WIND SPEED 5.0 M/S
BACKGROUN
DOttNWIND
DISTANCE
(EM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
ICO.
150.
2GO.
250.
3CO.
350.
'ISUAL RANGE
PLUTS-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.3
49.7
59.7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(.7.)
5.6
3.7
2.2
1.6
1.4
1.2
1. 1
1. 1
1.1
1. 1
1.2
1.3
1.3
1.4
1.4
1.3
BLUE-RED
RATIO
0.912
0.902
0.837
0.C52
0.C42
0.E23
0.616
0.823
0.834
0.869
0.901
0.947
0.972
0.936
0.992
0.996
PLUIZE
CONTRAST
AT 0.55
MICRON
-.057
-.047
-.041
- . 0-13
-.046
- . 043
-.052
-.052
-.051
-.047
- . 04-0
-.029
-.021
-.015
-.010
-.007
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
3.65
3.91
4.47
5.43
6.31
6.94
7.52
7.43
7. 10
5.87
4.62
2.75
1.62
0.95
0.58
0.36
286
-------
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
VIND SPEED =2.5 M/S
BACKGROUND VISUAL RANGE
PLUME-
DOVNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
OBSERVER
DISTANCE
(KM)
5.0
5.
5.
5.0
5.0
5.0
.0
,0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RANGE
REDUCTION
15.5
13.3
10.3
8.4
7.5
7.0
6.8
6.9
7.0
7.2
3.0
0.0
0.0
0.0
0.0
0.0
BLUE-RED
RATIO
0.967
0.936
0.917
0.915
0.914
0.913
0.937
0.968
0.935
0.998
1.000
1.000
1.000
1.000
1.000
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.022
-.037
- . 047
-.047
-.046
-.046
-.039
-.027
-.019
-.003
-.003
-.000
- . 000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A#B*)
2.46
4.35
5.48
5.59
5.60
5.63
4.29
2.42
1.39
0.40
0.15
0.03
0.00
0.00
O.OO
0.00
2000WW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =2.5 M/S
BACKGROUN
DOTVTIWIND
DISTANCE
(in-I)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
103.
150.
200.
250.
300.
350.
'ISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KTI)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.3
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(JJ)
14.7
12.2
9.1
7.2
4 6.4
5.9
5.6
5.6
5.8
6.2
6.6
7.2
7.2
3.1
0.2
0.0
BLUE-RED
RATIO
0.902
0.821
0.774
0.763
0.763
0.766
0.793
0 . 843
0.331
0.942
0.973
0.9C6
1.000
1 . 00 1
1.001
1.001
PLUME
CONTRAST
AT 0.55
MICRON
-.051
-.076
-.090
- . CS3
-.033
-.033
-.033
-.072
-.064
-.045
-.032
-.016
-.007
-.004
-.002
-.001
PLUME
PERCEPT-
IBILITY
E(L*A*Es)
5. 10
3.96
11.33
11.55
11.54
11.61
10.42
8.17
6.42
3.55
2.00
0.71
0.31
0. 15
0.03
O.C4
287
-------
2000MV COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED =2.5 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
flSUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 100. KM
VISUAL
RANGE
REDUCTION
(JO
13.9
11.4
8.3
6.5
5.6
5.2
4.8
4.8
4.8
5.1
5.5
6.2
6.8
7.3
7.6
8.0
BLUE- RED
RATIO
0.851
0.741
0.679
0.674
0.673
0.672
0.690
0.732
0.760
0.841
0.892
0.933
0.931
0.994
0.999
1.001
PLUME
CONTRAST
AT 0.55
MICRON
-.030
-. 106
-. 120
-. 117
-. 114
-. 113
-. 110
-.104
-.09S
-.033
-.072
-.052
-.036
-.025
-.017
-.012
PLUME
PERCEPT-
IBILITY
E( L*A*B*)
6.89
11.80
14.86
15. 10
15.06
15. 14
14.40
12.70
11.20
8. 17
5.94
3. 19
1.81
1. 10
0.73
0.50
2000WW COAL-FIRED PLANT
PASQUILL-CIFFORD F
WIND SPEED =2.5 M/S
BACKGROUH
DOWNWIND
DISTANCE
(EM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
VISUAL RANGE
PLU1G-
OBSERVER
DISTANCE
(KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59. 7
69.6
= 200. KM
VISUAL
RANGE
REDUCTION
(50
12.9
10.4
7.4
5.7
5.0
4.5
4. 1
4.0
4.0
4, 1
4.4
5.0
5.5
6.1
6.5
7.0
BLUE-RED
RATIO
0.796
0.673
0.6C3
0.603
0 . 6Co
0.605
0.616
0 . 645
0.672
0.733
0.7S6
0 . So 3
0.917
0.949
0.970
0.902
PLOTIE
CONTRAST
AT 0.55
MICRON
-. 113
-.141
-. 150
-.142
-.133
-. 136
-.133
-. ISO
-.127
-. 120
-.112
-.097
-.033
-.070
-.059
- .
-------
2000NW COAL-FIRED PLANT
PASQUILL-G1FFORD F
WIND SPEED =5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
OBSZRVER
DISTANCE
(KM)
DOW WIND
DISTANCE
(EM)
1.
2.
5.
10.
15.
20.
SO.
40.
50.
75.
100.
150.
25o!
SCO.
3CO.
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.3
39.8
49.7
59.7
69.6
= 20. KM
VISUAL
RAKGE
REDUCTION
(JO
8.9
6.a
4.7
3.8
3.4
3.2
3.2
3.3
3.4
3.6
1.7
0.0
0.0
0.0
0.0
0.0
BLUE- RED
RATIO
0.984
0.975
0.963
0.964
0.960
0.957
0.965
0.932
0.991
0.999
1.000
l.OCO
• l.OCO
1 . 000
LOGO
1.000
PLUME
CONTRAST
AT 0.55
MICRON
-.012
-.014
-.016
-.017
-.010
-.020
-.013
-.014
-.010
- . 004
-.002
-.000
-.000
-.000
-.000
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B#)
1.24
1.74
2.03
2.29
2.50
2.69
2.26
1.35
0.80
0.23
0.08
0.01
0.00
0.00
0.00
0.00
2000MW COAL-FIRED PLANT
PASCUILL-GIFFORD F
WIND SPEED =5.0 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KM)
1.
2.
15.
HO.
30.
<0.
50.
75.
100.
150.
200.
2-30.
300.
050.
rlSUAL RANGE
PLUI-ffi-
OBSERVER
DISTANCE
( KM)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.8
39.8
49.7
59.7
69.6
= 50. KM
VISUAL
RANGE
REDUCTION
(J?)
3.5
6.3
4.3
3.3
3.0
2.3
2.6
2.7
2.8
3. 1
3.4
3.7
3.9
1.8
0. 1
0.0
BLUE-RED
RATIO
0.932
0.923
0.911
0.902
0.893
6.834
0.837
0.909
0.928
0.963
0.932
0.997
1.000
1.000
1.000
l.OCO
PLUME
CONTRAST
AT 0.55
MICRON
-.023
-.031
-.033
- . 034
-.036
-.033
-.039
-.036
-.033
-.025
-.010
-.009
- . 004
-.002
-.001
-.000
PLUME
PERCEPT-
IBILITY
E(L*A*B#)
2.59
3.54
4. 19
4.59
5.00
5.38
5.34
4.49
3.70
2. 19
1.26
0.44
0. 18
0.03
0.04
0.02
289
-------
2000MK COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 5.0 M/S
BACKGROUND VISUAL RANGE
PLUKE-
OBSERVER
DISTANCE
(KM)
DOWNWIND
DISTANCE
(KM)
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
100.
150.
200.
250.
300.
350.
5.0
5.0
5.0
5.0
5.0
5.0
0.0
8.0
9.9
14.9
19.9
29.3
39.8
49.
59,
.7
.7
= 100. KM
VISUAL
RANGE
REDUCTION
69.6
8.0
5.9
4.0
3.0
2.6
2.4
2.3
2.3
2.3
2.5
2.8
3.2
3.5
3.7
3.8
3.9
BLUE-RED
RATIO
0.925
0 . 894
0.873
0.861
0.849
0.838
0.832
0.846
0.861
0.898
0.928
0.967
0.9G7
0 . 995
0.999
l.GOO
PLUME
CONTRAST
AT 0.55
MICRON
-.046
-.047
-.046
- . 646
-.047
-.050
-.052
-.052
-.051
-.046
-.041
-.030
-.021
-.014
- . 009
-.006
PLUME
PERCEPT-
IBILITY
E(L*A*B*>
3.55
4.65
5.41
5.90
6.40
6.89
7.24
6.83
6.32
4.97
3.76
2.06
1. 13
0.65
0.40
0.26
2000MW COAL-FIRED PLANT
PASQUILL-GIFFORD F
WIND SPEED = 5.0 M/S
BACKGROUN
DOWNWIND
DISTANCE
(KID
1.
2.
5.
10.
15.
20.
30.
40.
50.
75.
ICO.
15C.
200.
25C.
300.
35C'.
VISUAL RAKGE
PLUKE-
OBSERV2R
DISTANCE
IKE)
5.0
5.0
5.0
5.0
5.0
5.0
6.0
8.0
9.9
14.9
19.9
29.5
39. 3
49.7
59.7
69.6
= 2C;i. KM
VISUAL
RANGE
REDUCTION
(50
7.4
5.4
3.5
2.7
2.3
2. 1
2.0
1.9
1.9
2.0
2.2
2.5
2.8
3.0
3.2
3.4
BLUE-RED
RATIO
0.892
0.861
0.641
0.829
0.816
0.804
0.792
0.796
0.804
0.831
0.859
0.903
0.943
0.966
0.930
0.988
PLUME
CONTRAST
AT 0.55
MICRON
-.071
-.067
-.061
-.058
-.059
-.061
-.064
-.065
-.066
-.065
-.063
-.056
-.047
-.039
-.032
-.026
PLUME
PERCEPT-
IBILITY
E(L*A*B*)
4. 82
5.63
6.38
6.68
7.43
7.99
8.63
8. 65
8.49
7.74
6.78
4.90
3.44
2.41
1.72
1.27
290
-------
LEGEND:
1-500 HUE
. 2-1000 M'!E , 3-2000 HUE
20.0
15.0
10.0
u
£L
5.0
o.o
1.0
0.9
(E
S0.8
u.
UI.
°0.7
0.6
-0.00
-o.o:
,. -0.0?
•1
i -o.oe
5 '°- 1C
'--0.12
-O.H
-0.16
20.0
15.0
i i i i i I I )
j i i i i i i i i
•J.Q-
i i i i i
I I I I I I I I
J I
u
Q
5.0
0.0
.3.0-
I I I I I
10 20 40
DOWNWIND DISTflNCE (KM)
60 100
200
VISURL IMPRCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STRBILITY CLRSS C
2.5 M/S WIND SPEED
20.0 KM VISURL RRNGE
-------
LEGEND;
1-500 HUE
, 2-1000 HME . 3-2000 HUE
20.0
ea
£ 15.0
o
o
UJ
10-0
5.0
0.0
1.0
0.9
cc
o*
UJ
Ul
CD
0.7
0.6
-O.OC
-0.02
-0.01
-o.oe
j I i i t i t i i
I i i i i i i i i
I t
CO
g -0.08
| -0.10
°- -0.12
-0.14
-0.16
20.0
15.0
I I i i
I i
I i
UJ
cc
UJ
o
10.0
5.0
0.0
10 20
D0HNHIUD DISTANCE (KM)
VISURL IMPflCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STRBILITY CLRSS C
2.5 M/S WIND SPEED
50.0 KM VISURL RRNGE
292
-------
LEGEND:
1-500 HUE
2-1000 MWE
3-2000 HUE
20.0
§15.0
5.0
u
a.
0.0
1.0
0.9
l
UJ
3
"0.7
0.6
-0.00
-0.02
.-0.04
n
£-0.06
5-0.08
i i i i i i i i
-0.12
-O.U
-0.16
20.0
15.0
I t
I L L
I I I I I I I I
I I
5.0
0.0
10 20 40
D0HNHINO DISTRNDE (KM)
100
200
V3SURL IMPRCTS 0F P0WER PLflNTS 0F INDICRTED SIZE
STRBILJTY CLR55 C
2.5 M/S WIND SPEED
100.0 KM VISURL RRNGE 293
-------
LEGEND:
1-500 HUE
. 2-1000 MWE . 3-2000 HUE
20.0
15.0
o
«n
10.0
5.0
0.0
1.0
0.9
(E
Of
0.8
ee
iLl
0.7
0.6
-0.00
-0.02
f. -0.04
o
a: -0.06
I' -0.08
5 -0.10
5 -0.12
-O.H
-0.16
20.0
15.0
j i i i i \ i i i
I i i i i i i i
J I
J I I I I I I I I
u.1
a
LJ
o
10.0
5.0
0.0
10 20 40
D0HMHIND DISTflHCE (KM)
100
200
VISUAL IMPRCTS 0F P0WER PLflNTS 0F INDICRTED SIZE
STRBILITY CLR5S C
2.5 M/S WIND SPEED
200.0 KM VISURL RRNGE
294
-------
LEGEND:
i-soo MWE
2-1000 MHE
3-2000 MWE
20.0
2 15.0
u
I
UJ
5.0
in
a.
0.0
1.0
0.9
i-
(E
gO. 8
OS
U
3
"0.7
0.6
-0.00
-0.02
H-0.04
(0
K-O.OS
g-0.08
g-0.10
^-0.12
-O.H
-0.16
20.0
15.0
i iii i i i i
j _ i
i i i i i
•s.o-
I I I I I I I I
10.0
IU
o
5.0
0.0
I 1.1 IT
.3.0:
10 20 40 60
DOWNWIND DISTRNCE (KM)
100
200
VISURL IMPRCTS 0F P0WER PLflNTS 0F INDICRTEO SIZE
STRBILITY CLflSS C
5.0 M/S WIND SPEED
20.0 KM VISURL RflNGE 295
-------
LEGEND:
1-500 HUE
. 2-1000 HWE , 3-2000 HME
20.0
£ 15.0
o
o
10
«n 10.0
UJ
D-
5.0
0.0
1.0
0.9
cr
or
S 0.8
ce
i
m 0.7
0.6
-0.00
-0.02
K -0.04
-------
LEGEND:
1-500 HUE
. 2-1000 HUE . 3-2000 HUE
20.0
2 15.0
10.0
8
v>
n
>
I-
\ 5.0
£L
0.0
1.0
0.9
a
et
ft
U!
3
"0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.0
i i i i I i
I i i I i I i i i
J I
10.0
5.0
0.0
D0HNHIND DISTflNCE (KM)
VISURL IMPflCTS 0F P0WER PLflNTS 0F IND1CRTED SIZE
STRBILITY CLR5S C
5-0 M/S WIND SPEED
100.0 KM VISURL RRNGE 297
-------
LEGEND:
1-500 HUE
, 2-1000 MWE , 3-2000 MWE
20.0
IB
15.0
Q
IU
K.
tn
10.0
ui
a.
5.0
0.0
1.0
e
i—i
i-
cr
0.9
S 0.6
(£.
LD
_l
03 0.7
0.6
-0.00
-0.02
-0.09
-O.OS
-0.08
0.10
-0.12
-0.14
-0.16
20.0
15.0
10.0
5.0
0.0
J I
a
ce
u
UJ
x:
I I I I I II
I I
lu
cr
»-
_i
10 20 €0 60
D0HNHIND DISTRNCE (KM)
VISUflL IMPflCTS 0F P0WER PLflNTS 0F INDICRTED SIZE
STRBILITY CLflSS C
5.0 M/S WIND SPEED
100
200
200.0 KM VISURL RRNGE
298
-------
LEGEND:
1-500 MWE
. 2-1000 MWE , 3-2000 MWE
20.0
15.0
10.0
g 5.0
0.0
1.0
0.9
50.8
K
til
10 0.7
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.0
10.0
5.0
0.0
i I I I I I i I
' ' i i i i i i
\u
10 20
WMNHIND DISTflNCE (KM)
^I|I' 'I'''
40 60 100
VISURL IMPRCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STRBILITY CLRSS D
2.5 M/5 WIND SPEED
20.0 KM VISURL RRNGE 2"
-L L
200
-------
LEGEND:
1-500 MWE
. 2-1000 MWE . 3-2000 HUE
20.0
~ 15.0
CJ
o
u
« 10.0
5.0
0.0
1.0
3.0-
(9
•«*
cr
0.9
£ 0.8
UJ
0.7
0.6
-0.00
-0.02
-------
LEGEND:
1-500 MUE
. 2-1000 HUE
3-2000 HUE
zo.o
15.0
~ to.o
i 5.0
j
0.0
1.0
0.9
gO.8
U
mo.?
0.6
-0.00
-0.02
h -0.04
in
K-0.06
2-0.08
3.0—
i l ~r—i—r i i r
i t i i i i i
J I
-O.H
-0.16
20.0
1S.O
10.0
S.O
0.0
J L
I ' 'I—1 I I U-
J L
DJHNHINO DISTflNCE (KM)
VISURL IMPRCTS 0F P0WER PLRNTS 0F IND1CRTED SIZE
STRBILITY CLRSS D
2.5 M/5 W]NO SPEED
300.0 KM VISURL RflNGE 301
-------
LEGEND:
1-500 HUE
, 2-1000 HUE . 3-2000 HUE
20.0
£ 15.0
u
CD
UJ
^ 10.0
5.0
0.0
1.0
0.9
a:
Qi
0.6
I i i i i i ii
Z
s
D
UJ
5
_i
a.
-0.04 -
-0.06i
-0.06
-0.10
-0.12
-0.14
•0.16
I i i i i i |
i i i
-U-
20.0
15.0
(Li
cr
UJ
o
10.0
5.0
0.0
10 20 40 60
DOWNWIND DISTflNCE (KM)
100
200
V1SURL IMPflCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STflBILITY CLR5S D
2.5 M/S WIND SPEED
200.0 KM V1SURL RRNGE 302
-------
LEGEND:
1-500 HUE
. 2-1000 HUE
3-2000 MHE
20.0
\ 15.0
u
5.0
0.0
1.0
3.0-
0.9
c
gO. 8
tu
01 0.7
-0.02
,...-0.04
inn
VK -0.06
gS-0.08
g-0.10
JJ
L'-0.12
-0.14
-0.16
20.0
15.0
•3.0-
i i i
i I i
j J
j i i i i i i
t. in
ox
10.0
uki
CD
5.0
TO 2
C3WNMIMD DISTflNCE (KM)
60
100
VISURL IMPRCTS 0F P0WER PLRNTS 0F 1NDICRTED SIZE
STRBILITY CLR5S D
5.0 M/S WIND SPEED
20.0 KM VISURL RRNGE
303
200
-------
LEGEND:
1-500 MWE
. 2-1000 MWE . 3-2030 MWE
20.0
£ 15.0
o
Q
ILJ
10.0
tK.
UJ
0-
-------
LEGEND:
1-500 MWL
2-1000 MWE
3-2000 MHE
20.0
5 15.0
10.0
I I I I I I I I I
I I I I I I I I I
0.0
D0HNHIND DISTRMCE (KM)
VISURL IMPRCTS 0F P0WEF PLRNTS 0F INDICRTED
STRBILITY CLRSS D
£.0 M/S WIND SPEED
100.0 KM VISURL RRNGE 305
-------
LEGEND:
1-500 HHE
. 2-1000 HUE . 3-2000 MHE
20.0
P 15.0
u
cr>
10.0
5.0
0.0
1.0
.0.9
»*
«
at
g 0.8
oe
10
0.7
0.6
-0.00
-0.02
i i i i i
i i i i i i i i
j i
,_
-0.06
-0.08
-0.10
•0.14
-0.16
20.0
15.0
1 1 1 I I I ,1,1
J L
u
10.0
UJ
5.0
0.0
D0HNHIND DISTRNCE (KM)
V15URL IMPRCTS 0F P0WEP PLRNTS 0F INDICATED SIZE
STRBIL1TY CLRSS D
5.0 M/S WIND SPEED
200.0 KM VISURU RRNGE 306
-------
LEGEND:
i-soo HWE
2-1000 MME
3-2000
20.0
| 5.0
iu
o.
0.0
1.0
0.9
80-8
U
"0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.18
20.0
15.0
I i i i i i i i i
j I
J L
UJ
10.0
5.0
0.0
i i i
100
200
00WMWIND DlSTflNCE (KM)
VISURL IMPflCTS 0F P0WER PLflNTS 0F INDICflTED SIZE
STRBILITY CLflSS E
2.5 M/S WIND SPEED
20.0 KM VISUflL RRNGE 307
-------
LEGEND:
1-500 HUE
. 2-1000 HUE . 3-2000 MWE
20.0
z
Ei
r is.o
o
en
10.0
5.0
0.0
1.0
1.0
cc
ee
S 0.8
or
CO
0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.0
10.0
I I I I i i i I
CO
cr
on
o
UJ
I I I I I I I I
I I
1U
(X
UJ
a
5.0
0.0
10 20 40
DOWNWIND DISTflNCE (KM)
60 100
200
VISURL IMPflCTS 0F P0WER PLRNTS 0F INDICflTED SIZE
5TRBILITY CLR5S E
2.5 M/S WIND SPEED
50.0 KM VISURL RRNGE 308
-------
LEGEND:
1-500 HUE
. 2-1000 MWE , 3-2000 MWE
TO20 40
DOWNWIND DISTANCE (KM)
60 100
200
VISURL IMPRCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STRBILITY CLRS5 E
2.5 M/S WIND SPEED
100.0 KM VISURL RRNGE 509
-------
LEGEND:
1-500 MHE
, 2-1000 MME . 3-2000 MME
20.0
~ 15.0
u
Q
UJ
o:
tn
10.0
£ 5.0
UJ
Q.
0.0
1.0
0.9
cc
tc
SO.8
os.
UJ
0.7
0.6
-0.00
-0.02
_ -0.04
to
£ -0.06
i i i i i i i i i
I i I i i I I
j i
-0.08
UJ
-3.10
••>
°- -0.12
-0.14
-0.16
20.0
15.0
I I I J__J I I I I
j I
u.
a
u.
c.
10.0
5.0
0.0
TO ~20~ 40
D0HNWIND DISTANCE (KM)
60 100
V15URL 3MPRCTS 0F P0WER PLflNTS 0F IND]CRTED SIZE
STflBILlTY CLRSS E
2.5 M/S WIND SPEED
200.0 KM VISUflL RRNGE 310
200
-------
LEGEND:
1-500 HUE
. 2-1000 HWE . 3-2000 MWE
20.0
pis.o
10.0
5.0
u
a.
0.0
1.0
0.9
gO.6
iu
u
0.7
0.6
-0.00
-0.02
,.-0.04
to
fc-0.06
z
5-0.08
LJ
§-0.10
"•-0.12
-0.14
-0.16
20.0
15.0
10.0
5.0
0.0
j i i i ill
i l i l i i i i
I I
i t i t i i
l I I I l l l l
J I
10 TO 40 60 100
00HHHIND DISTflNCE (KH)
VISUflL IMPRCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
STRBILITY CLflSS E
5.0 M/S WIND SPEED
20.0 KK VISUflL RRNGE 311
J L
200
-------
LEGEND:
1-500 HUE
. 2-1000 MrtE . 3-2000 MWE
20.0
s
P 15.0
I
g 5.0
tu
o.
0.0
1.0
tr
0£
0.8
111
0.7
0.6
-0.00
-0.02
-0.04
i§ -0.06
3 -o.os
l-o.io
^-0.12
-0.14
-0.16
20.0
15.0
j i
t I I I i t i I
j I
to
ui
oc
IU
a
10.0
5.0
0.0
Jill
10
0HNMIND DISTflNCE (KM)
V3SURL IMPRCTS 0F P0WEK PLRNTS 0F INDICRTED SIZE
STRBILITY CLRSS E
5.0 M/S WIND SPEED
50.0 KM VISURL RRNGE 312
-------
LEGEND:
i-soo HUE
, 2-1000 HUE
3-2000 HUE
20.0
15.0
10.0
ui
o.
5.0
0.0
1.0
0.9
gO.8
at
UI
"0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-0.14
-0.16
20.0
15.0
i
10.0
5.0
0.0
3,0-
i i
i i i i i i
' ill 1 I I I I
iu
Q
TO 20
D0WHWIND DISTRNCE (KM)
200
V1SURL IMPRCTS 0F POWER PLflNTS 0F INDICRTED SIZE
STRBILITY CLRSS E
5.0 M/S WIND SPEED
100.0 KM VISURL RRNGE 313
-------
LEGEND:
1-500 MWE
, 2-1000 HUE . 3-2000 MWE
20.0
p 15.0
CJ
to
10.0
£ 5.0
LJ
0-
0.0
1.0
,5,0-9
»—i
t-
cr
OC
SO.8
UJ
00 0.7
0.6
-0.00
-0.02
,_ -0.04
to
| -0.06
g -0.08
| -0.10
°- -0.12
-O.H
-0.16
20.0
15.0
3.0-
j i
I i
I I I I I I I I
J I
j i
i i i i i i
UJ
-------
LEGEND:
i-soo MME
2-1000 HUE
3-2000 MME
20.0
15.0
10.0
\ 5.0
w
a.
0.0
1.0
I I I I i i i i i
0.9
a
te
ut
D
"0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.0
3.0-
i i i i i t i i
J I
-3.0
J L
,10.0
•J
L'J
D
5.0
0.0
200
D0HNMIMD DISTflNCE IKM)
VISURL IMPflCTS 0F P0WER PLflNTS 0F IND1CRTED SIZE
STRBILITY CLRSS F
2.5 M/S WIND SPEED
20.0 KM VISURL RRNGE 315
-------
LEGEND:
1-500 MME
, 2-1000 HUE , 3-2000 MWE
20.0
15.0
tft
10.0
5.0
0.0
1.0
0.9
SO-8
eg
bJ
CD
0.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.0
10.0
5.0
0.0
i 11 i ill
J I
to
a
K.
6)
CJ
U)
r>
I i i
i i i i
I I I I I I I
10 20
00MNHIND DISTANCE (KM)
60 100
200
V15URL IMPRCTS 0F P0WER PLRNTS 0F INDICRTED SIZE
5TRBILITY CLRSS F
2.5 M/S WIND SPEED
50.0 KM VISUflL RRNGE 316
-------
LEGEND:
1-500 MNE
. 2-1000 MKE . 3-2000 MWE
20.0
15.0
0.0
1.0
0.9
c
et
jjJO.8
K
U
°0.7
0.6
-0.00
-0.02
to
K-0.06
S-0.08
| -o.io
••-0.12
-0.14
-0.16
20.0
15.0
J I
I I
I I I i
u
K
u
D
5.0
0.0
;UNWIND DISTflNCE tKHJ
VISUflL IMPRCTS 0F P0WER PLflNTS 0F INDICflTED SIZE
STRBILITY CLR55 F
2.5 M/S WIND SPEED
100.0 KM VISURL RRNGE
-------
LEGEND:
1-500 HUE
. 2-1000 HUE , 3-2000 MHE
20.0
P 15.0
i
10.0
UJ
tL.
5.0
0.0
1.0
0.9
te.
in
"° 0.7
0.6
-0.00
-0.02
_ -0.04
CO
| -0.06
g -0.08
I "°-10
°- -0.12
-O.H
-0.16
20.0
I i i I I I I I
I I
I I I I
0.0
tO 20 40
CJWNHIND DISTRNCE (KM)
200
VISURL IMPflCTS 0F P0WER PLflNTS 0F INDICflTED SIZE
STRBILITY CLRS5 F
2.5 M/S WIND SPEED
200.0 KM VISURL RRNGE 318
-------
LEGEND:
J-500 MME
. 2-1000 MHE , 3-2000 HUE
20.0
15.0
10.0
u
0.
5.0
0.0
1.0
II i iii
0.9
c
50.8
K
U
n0.7
0.6
-0.00
-0.02
,.-0.04
n
i -0.06
8 0.08
§ °-10
-O.H
-0.16
20.0
15.0
I 1 1 I I I I I
i i i i i i i i
j i
' ' '—I I I I
J_L
J L
10.0
5.0
o.o
i I I
0 20 40 60 100
D0MNHIND DISTflMCE tKM)
V3SURL IMPRCTS 0F P0HER PLflNTS 0F INDICRTED SIZE
STRB3LITY CLRSS F
5.0 M/S WIND SPEED
20.0 KM VISUflL RRNGE 319
200
-------
LEGEND:
1-500 MWE
. 2-1000 HUE . 3-2000 HWE
20.0
0.8
Of
UJ
CD
0.7
0.6
-0.00
-0.02
-0.04
-0.06
i-
g -0.08
iii
= -0.10
°- -0.12
-O.H
-0.16
20.0
15.0
UJ
£ 10.0
LJ
D
5.0
0.0
i i i I I i i i I
j i
to
cr
D0-IHHIND DISTANCE (KM)
VISURL IMPflCTS 0F P0WER DLflNTS 0F INDICflTED SIZE
STRBILITY CLRSS F
5.0 M/5 WIND SPEED
50.0 KM VISURL RRNGE
320
-------
LEGEND:
1-500 HWE
2-1000 MWE
3-2000 MWE
20.0
S 15.0
o
t-
\ 5.0
u
0.
0.0
1.0
0.9
i—i—i i r
3
00.7
0.6
-0.00
-0.02
-0.04
-0.06
-0.08
-0.10
-0.12
-0.14
-0.16
20.0
15.0
i i i i i
' i i i i i i i
UJ
j-10.0
8
5.0
0.0
DHUNWIND DISTRNCE (KM)
VISURL IMPRCTS 0F P0WER PLRNTS 0F INDICflTED SIZE
STRBILITY CLRSS F
5.0 M/S WIND SPEED
100.0 KM VISURL RRNGE 321
-------
LEGEND:
1-500 HUE
. 2-1000 HUE . 3-2000 MI'E
20.0
£ 15.0
LJ
O
LJ
«, 10.0
UJ
5.0
0.0
1.0
S 0.8
a:
LJ
=>
m 0.7
0.6
-0.00
-0.02
-0.01
-0.06
-0.08
-0.10
-0.12
-O.H
-0.16
20.0
15.C
10.0
5.0
0.0
J I
I I I I I
J I I I I I I I I
J I
LJ
1 1 ' I I I I I
' ' I I I I I I I
UJ
-------
APPENDIX E
TWO EXAMPLE APPLICATIONS OF THE LEVEL-1 AND LEVEL-2 ANALYSES
E.I EXAMPLE 1--COAL-FIRED POWER PLANT
E.I.I Level-1 Analysis
This example is based on a hypothetical coal-fired power plant that
has been proposed for a site approximately 70 km from a class I PSD
area. The emission rates for this hypothetical power plant are projected
to be 25 g/s of particulates, 380 j/sec of nitrogen oxides (as N02), and
120 g/sec of sulfur dioxide. Figure E-l shows the relative locations of
the proposed site and the class I area. The Federal Land Manager has
identified the view toward the mountains to the west as integral to the
visitors' experience of the class I area. The discussion below demon-
strates the way in which potential visibility impairment in this situation
would be evaluated with the level-1 procedure.
The level-1 procedure steps are carried out as follows:
*
1 p = Z-0 x 10 x = 60 km
K ax
z oz (60 km) = 83 m
p = 4.0 x 104
2. Tpart = 1.0 x 10-6 • P • Qpart
*N02 = l'7 X 10"7 * P ' QN°X
* Distance from site to closest point of impact, which is the vista to the
west.
323
-------
CO
ro
VISITORS'
CENTER
PROPOSED POWER
PLANT LOCATION
Scale in kilometers
CLASS I AREA
Figure E-l. Relative locations of the proposed power plant and class 1 area
for example 1.
-------
p =
'part
4.0 x 104
25 g/s
2.16 MT/day
380 g/s
32.8 MT/day
Tpart = °-0864
TNO =0.223
3. rVQ = 170 km
(The proposed site is in the west-central United States.)
4- T
aerosol
10"5) ' r '
vO
rvO
Qpart
= 170 km
=2.16 MT/day
= 120 g/s
= 10.368 MT/day
'aerosol s °-0284
5.
TNO,
Tpart TNO,
Co =
' exP(-T
'part
I 1) exp(-Tpart "
exp(-0.78 x/ry0)
exp(-1.56
C3 = 0.368
- exp(-Taerosol)
325
-------
TNO = 0.223
'part ' °-°864
x = 60 km
rv0 = 170 km
'aerosol = °-02837
= -0.146
C2 = 0.0814
C3 = 0.0103
6. The absolute value of C1 is greater than 0.10. Therefore, a level-2
analysis is indicated. Atmospheric discoloration due to N02 is
expected to be the most serious problem.
E.I. 2 Level-2 Analysis
The design parameters for the proposed power plant are:
Stack height "stack = ^ m
Stack inside diameter D = 8 m
Stack gas velocity Vs = 15 m/s
Stack temperature TS = 350DK
Particulate emissions rate %art = 25 g/s
= 2.16 MT/day
NOX emissions rate (as N02): QNQ = 380 g/s
X = 32.8 MT/day
SOX emissions rate (as S02): Q$Q = 120 g/s
= 10.4 MT/day
Site elevation zsite= 94° m MSL
326
-------
E.I.2.1 Calculating Terrain Effects on Plume Transport
The level-2 analysis proceeds as described in the text. First, the
potential for interference by terrain features on plume trajectories is
identified by comparison with effective stack height.
The equation given for Ah in the text,
)* - 1.6 • F1/3 (3.5 x*) 2'3 • u'1
reduces to:
^ a (21.4 F3/4 • u"1 for F < 55 mV3
) -1 *
V38.7 F3/5 * u for F > 55 mV3
where, as before,
* / T \
c « y /i 'ambient \
F - g — II - — 1
* \ 'stack /
. v. ir d 2
V = -£-T,
hstack • 15° m
u = 5 m/s
vs - 15 m/s
d = 8 m
nbient • WC - 283'K
Tstack ' 350'K
g = 9.8 m/s2
_ 15 m/s »3.14 • 82 m2
4
327
-------
V = 754 m3/s
P (9.8 m/s2)(754 m3/s) . /, 283°K \
F= TPT" \l 35W/
F = 450 m4/s3
^ _ 38.7(450)3/5
Ah = 302 m
H = 150 m + 302 m
H = 452 m
zblock = zsite + H + 500 m
zblock = 94° m + 452 m + 50° m
zblock • 1892 m
Figure E-2 shows the area above Zb-joc|< in the vicinity of the class I area
and the proposed power plant, along with trajectories affecting visibility
in the class I area. Figure E-3 shows terrain elevation plots for several
lines of sight from within the class I area.
E.I.2.2 Estimating Worst-Case Meteorological and Ambient Conditions
Worst-case conditions ^or plume disco1oration--To characterize worst-
case meteorological conditicns, we obtained meteorological data from an
airport 100 km west of the proposed power plant. Although the intervening
terrain is not flat, we judged that the 850 mb wind and stability data are
the best available data source. For the trajectory passing to the north-
west of the class I area, we tabulated winds from the southwest and west-
southwest for both morning and afternoon soundings. From these tabula-
328
-------
GO
ro
VISITORS'
CENTER
PLUME TRAJECTORIES
PROPOSED POWER
PLANT LOCATION
TERRAIN ABOVE Z
block
Scale in kilometers
CLASS I AREA
Figure E-2. Significant terrain features and possible plume trajectories.
-------
c.
c>
•f
4->
(T
a>
70
60
50
(a) View 1:
VISITORS' CENTER
40 30
Distance (km)
To the west from /isitors1 Center (A = 270°)
c
o
VISITORS' CENTER
•M
(0
>
QJ
LU
\
- ^x^
^•^
\ \ \ \
70 60 50 40 30
—-^
RIVERA
— • — -^__^-
^^
1
20
^ \
V^^1
"***T^"^ 1
10 C
Distance (km)
(b) View 2: To the west-northwest frofo Visitors' Center (A = 292.5°)
VISITORS' CENTER-
40 30
Distance (km)
(c) View 3: To the south-southeast from Visitors' Center (A = 135°)
Figure E-3. Terrain elevation plots.
330
-------
tions, a frequency of occurrence (table E-l) was developed. The cumula-
tive frequency entries show that on three to four days per year conditions
with ozu values of 322 m2/s. (E stability, 2 m/s) can be expected. Note
that the bulk of the contribution tD the cumulative frequency (0.9% out of
1.0*) represents the 1200 GMT E,2 dispersion conditions. This corresponds
to approximately 5 a.m. 1ST. Note also that the afternoon sounding fre-
quency of E,2 dispersion conditions was relatively high (0.6 percent, or
about two days per year).
Worst-case conditions for general haze*—Because of time and resource
considerations, we decided to rely initially on Holzworth (1972) for the
necessary data for the determination of episode frequency. A large scale
map was obtained, on which circles of radii of integer multiples of 173 km
(transport limit per 2 m/s of wind speed) were drawn, centered on the site
of the proposed power plant. Class I areas were marked, and the wind sec-
tors associated with transport to each area were noted, as shown in figure
E-4. From this figure and the two-day-episode data for mixing height and
wind speed in Holzworth (1972) (figures 51 through 62),f table E-2 was
constructed. The worksheet i'i figure E-5 shows the extraction of the
actual frequency of specific dind speeds and mixing depths for second-and-
later episode days from the cumulative data presented in Holzworth. The
four-day-per-year uHm value is 4000 m2/s. Note that the principal contri-
bution to the frequency of occurrence of this condition derives from a
high incidence of greater-then-two-day episodes of H,,, between 500 and
1000 m and t between 2 and 4 Vs. This observation is confirmed by the
five-day-episode data in figure 65 of Holzworth (1972), which show eight
episodes lasting a total of 65 days for H < 1000 m and u < 4 m/s.
* Note that since C3 was less than 0.1, we could have eliminated this
step. However, for purposes of illustration this step is shown.
* The numerical values chosen here assume that Grand Junction, Colorado
data best characterize the conditions affecting our hypothetical power
plant.
331
-------
TABLE E-l.
FREQUENCY OF OCCURRENCE OF SW AND WSW WINDS BY DISPERSION
CONDITION AND TIME OF DAY
Dispersion
Condition
F, 1
E, 1
D, 1
F, 2
E, 2
D, 2
F, 3
E, 3
F, 4
D, 3
F, 5
E, 4
D, 4
F, 6
E, 5
+
°zu Transport Time Time of Da*"
(m2/s)
83
161
353
166
322
706
249
483
332
1060
415
644
1410
498
805
(hrs)
33
33
33
11
11
• 11
7
7
5
7
4
5
5
4
4
OOZ
0
0
0
0.1
0.6
1.6
0
0.6
0
3.4
0
0.4
2.4
0
0.2
121
0
0
0
0
0.9
0.8
0
1.4
0
1.2
0.1
1.2
1.5
0
1.8
Frequency
(*)
N/A
N/A
N/A
0.1
0.9
1.6
0
1.4
0
3.4
0.1
1.2
2.4
0
1.8
Cumulative
Frequency
(*)
N/Af
N/Af
N/Af
0.1
1.0
2.6
2.6
4.0
4.0
7.4
7.5
8.7
11.1
11.1
12.9
OOZ refers to midnight Greenwich mean time (GMT) and 12Z to noon GMT.
Persistence of stable meteorological conditions for over 12 hours is not con-
sidered likely. Therefore, conditions requiring greater than 12-hour trans-
port time are included in the cumulative frequency computation, but would not
be selected as representative of the "1-percentile event."
332
-------
LEGEND
® PROPOSED POWER PLANT SITE
.SE = CLASS I AREA LOCATION, AND
WIND SECTOR THAT RESULTS IN
TRANSPORT FROM PROPOSED SOURCE
Figure E-4. Class I areas within 48-hour transport range at
wind speeds up to 8 m/s.
333
-------
TABLE E-2. FREQUENCY OF EPISODE DAYS BY MIXING DEPTH AND WIND SPEED
Number of Occurrences
Affecting Class I Area
u, HJJ,
2, 500
2, 1000
4, 500
2, 1500
6, 500
2, 2000
4, 1000
4, 1500
6, 1000
4, 2000
6, 1500
6, 2000
u H
(m2/s)
1000
2000
2000
3000
3000
4000
4000
6000
6000
8000
9000
12000
(Day 2+ fre-
quency per
five years)
10
3
15
1
1
. 0
72
49
25
23
57
37
Sectors with
Class I Areas
(ns)
1
1
3
1
3
1
3
3
3
3
3
3
Sectors
,
0.25
0.075
1.125
0.025
0.075
0
5.4
3.675
1.875
1.725
4.275
2.775
per Year
Cumulative
0.25
0.325
1.45
1.475
1.55
1.55
6.95
10.625
12.5
14.225
18.5
21.275
Example based on Grand Junction, Colorado.
* From frequency worksheet shown in figure E-5.
§ f _ 2+ * "s _ Class 1 sector impact days
5 • 16 ~ year
334
-------
5-year Cumulative (I.e.. I < u. < H)
No. of Episodes
Lasting at Least
2 Days
2, 500 7
4, 500 12
6, 500 12
2, 1000 9
4, 1000 29
6, 1000 40
2, 1500 10
4, 1500 43
6, 1500 64
2, 2000 10
4, 2000 51
6, 2000 72
No. of No. of 2nd
Episode Days and Later Days
(fd) '
17
37
38
22
129
166
24
193
297
24
224
365
10
25
26
13
100
126
14
150
233
14
173
293
No. of 2nd and Later Days
for Specific Conditions
(from matrix below)
10
15
1
3
72
25
1
49
57
0
23
37
Sum = 293
= fd (6, 2000)
- fe (6, 2000)
4-6
0-2
26
1
(•26-25)
3rd
25
15
(-25-10)
2nd
10
10
(base case)
l"
126
25
(-126-100-1.
or 126-26-72-3)
6th
100
72
(-100-25-3.
or 100-13-15)
5th
13
3
(-13-10)
4th
233
57
(-233-126-49-1.
or 233-150-25-1)
9th
HO
49
(-150-101. or
150-14-7 ?-15)
8th
14
(•!' 3)
7th
293
37
(-293-233-23-0, or
293-173-57-25-1)
12th
173
23
(-173-150-0 or
173-14-49-72-15)
11th
14
0
(-14-14)
10th
0-500
500-1000 1000-1500
H (n)
1500-2000
LEGEND
Order of
calculating
Calculation o
f2+ (shown
only for
exai(>le)
J
Total nunber of7
second and later
episode days with
u and H£ stated
values
of second and
later days within
Stated u and H ranges
Figure E-5. Worksheet for the calculation of windspeed and mixing
depth joint frequency distribution
335
-------
Background Ozone Concentration—According to the "W" notation in
figures 51 through 62 in Holzworth (1972), limited mixing episodes occur
predominantly during winter months in the vicinity of Grand Junction,
Colorado. Also, in the same reference, table B-l gives seasonal mean mix-
ing depths and wind speeds. According to this table, the uH value by
season is most limiting for winter (uH = 3333, 19448, 22981, and 9011
m2/s, respectively, for winter, spring, summer, and autumn). Therefore,
in the absence of any other data for ozone aloft, a conservative winter
median ozone estimate of 50 ppb (0.05 ppm) was taken from figure 19 of the
text.
Background Visual Range—Telephotometer data for several months are
available, and we have-interpreted them as indicating a median rVQ of 140
km; however, this data set is relatively small. Therefore, the more con-
servative estimate of 170 km from figure 13 of the text was chosen for the
initial level-2 analysis, based on our recognition that the analysis can
be revised as more telephotometer data are generated.
E.I.2.3 Calculation of Worst-case Visual Impacts
The level-2 hand calcula'.ion procedure is demonstrated in this
example. A comparison with the results obtained from reference tables and
figures appears at the end of this example.
Determining plume-observer-object-sun geometry—Figure E-6 shows
plume-observer orientations corresponding to the terrain elevation plots
of figure E-3. Plan views of assumed geometries are shown in figures E-7
and E-8. From these figures, the following angles are determined:
Azimuth:
Ax = 270
A2 = 232.5
A3 = 157.5
336
-------
VIEW 2
OJ
VIEW
VISITORS^
CENTER )
CLASS I
BOUNDARY
PLUME
CENTERLINE
Figure E-6. Observer-plume orientations.
-------
VIEW 2
CO
10
CO
VIEW 1
a, = 36
o/ VISITORS' CENTER
Figure E-7. Plan view of assumed geometries for views 1 and 2.
-------
VIEW 3
C*>
,r0 =12 km (CLASS I BOUNDARY)
3
Figure E-8. Plan view of assumed geometry for view 3,
-------
Angle to plume center! ine:
<*± = 36°
02 = 58.5°
03 = 99°
We chose these lines of sight as the principal vistas for analysis because
of the steep terrain and resulting obstructions surrounding the class I
area. Therefore, rather than computing scattering angles for o= 30°,
45C, 60°, 90°, 120°, 135°, and 150° for both plume centerlines, we chose
to study azimuths including the three principal vistas plus three flanking
lines of sight for each plume trajectory. Specifically, for the plume
trajectory to the northwest of the class I area, azimuths corresponding to
o= 30°, 45°, and 90° are designated A4, A5, and Ag. For the plume tra-
jectory passing to the south, azimuths Ay, Ag, and Ag correspond to o
values of 90°, 120°, and 135°. Thus, we computed azimuths for views
1 through 3 as follows:
Traj.ectory for views 1 and 2:
c^ = 30° + A4 = 264°
05 = 45° •*• A5 = 279°
c = 90° -> A = 324°
Trajectory for view 3:
07 = 90° «• A7 = 166.5°
OQ = 120° -»• A8 = 136.5°
09 = 135° + Ag = 121.5°
We computed scattering angles for three scenarios corresponding to
rmrning, midday, and late afternoon in early winter (December 21, Julian
d.ite 355). Values calculated for these scenarios are subscripted M, N,
and A, respectively, in the calculations below:
340
-------
cos 6^ = -cos 6 sin * cos A.J cos
+ cos « sin A1 sin Hj
+ sin 6 cos * cos Ai
« = 23.
1 = 1. 2, 3
j = M, N, A
n = 355
4> = latitude = 39° N
HM = 45° (for 9 a.m.)
HN = 0° (for noon)
HA = -60° (for 4 p.m.)
Ax = 270°
A2 = 292.5°
A3 = 157.5°
A4 = 264°
A5 = 279°
A6 = 324°
A7 = 166.5°
A8 = 136.5°
A9 = 121.5°
6 = 23.45 Sin [360°
= 23.45 sin (270.2°)
6 = -23.45°
cos e^ = -(cos - 23.45°) (sin 39°) (cos 270°) (cos 45°)
+ (cos - 23.45°) (sin 270°) (sin 45°)
- (sin -23.45°) (cos 39°) (cos 270°)
cos ejM = -0.6487
* 130°
341
-------
Similarly, e^ values are derived for the other azimuth/time-of-day pairs,
as shown in table E-3.
E.I.3 Calculation of Plume Optical Depth
The plume flux of scattering coefficient, Qscat-part» is calculated
with a particle-size distribution different from those used in the level-1
analysis. The values chosen here are expected to more accurately charac-
terize emissions from this proposed project. Specifically:
n
^scat-part ~
Vt
-(bscat/v)
Qpart = 2.16 MT/day
p = 2 g/cm3
DG = 1 wn
^scat-part
0.55 un
63 m2/s
bscat/V = 0.05 (from figure 24)
For the determination of NOX concentration, we have
6.17 • Q
NO.
o_ux
342
-------
TABLE E-3. VALUES OF
co
CO
J (Hj)
M(45')
N(O')
A(60°)
1
(270°)
130
90
37
2
(297.5')
151
110
60
3
(157.5')
24
35
76
4
(264')
125
85
32
5
(279')
139
98
46
6
(324°)
164
136
91
7
(166.5")
32
30
67
8
(136.5')
15
50
97
9
(121.5')
22
62
111
-------
QNOV =
X =
32.8 MT/day
322 m2/s (from table
E-l)
60 km
NOX = 0.0105 ppm
As the background ozone concentration (0.05 ppm) is greater than this cal
culated value for [NOXJ, we may assume complete conversion of NO to N02-
Thus:
[N02]
x = 60
• [NOX]
= 0.0105
x = 60
Although we are concerned about nighttime stable transport of pollutants,
as a check on the extent to which we may be overestimating [N02] during
daylight hours, we have also calculated [N02] using the alternate formula-
tion.
[N02] = 0.5
[NOJ + h + j -
([NOJ + h + j)2 - 4 [NOJ h
•I1"] •
Values of Zs of 90°, 75°, 45° and 0° are computed, yielding the following:
zs
90°
75°
45°
0°
[N02]
0.0105 ppm
0.0093
0.0080
0.0077
Thus, even with the sun directly overhead (which would not occur for the
latitude and season of concern), there is a relatively small difference in
projected [N02]. For the remainder of the level-2 analysis, therefore, we
will continue to use the more conservative value of 0.0105 ppm.
344
-------
The optical thickness of the plume resulting from N02 is calculated
for X * 0.40, 0.55, and 0.70 un, using the equation:
TN02 = °-398 [NOg] ' x ' (WPP")
[N02] * 0.0105ppm
x = 60 km
1.71 for X = 0.40 un
°-31 for x = 0.55
0.017 for X = 0.70
TNQ = 0.429 at X * 0.4 un
TNQ = 0.073 at X * 0.55 un
T«Q - 0.00426 at X * 0.7 un
2
Light scattering by sulfate aerosol is calculated under the 40
percent relative humidity assumption for the western United States. Thus,
43-4 • kf • QSOZ (
Qscat-S04 = (kf + kd)(l - RH/100) j1'
kd = Vd/Hm • 3600
kf « 0.1 %/hr (winter)
Vd « 0.5 cm/s
« 2000 m*
QS02 * 10.4 MT/day
RH - 40%
* Note from table E-2 that either 1000 or 2000 m could be assumed for Hm.
In this equation, the higher value of Hm yields the most conservative
result. Therefore,' 2000 m has been used.
345
-------
Therefore,
k' = kf + kd = 1.OS/hour
and
'scat-SO,
=28.7 m2/s
X=0.55 mi
Next, Qscat wavelength dependence is determined via the equation
'scat
= Q
scat
0.55 un
which is based on the proportionality of Qscat and bscat. Thus,
'scat-part
X=0.4
= Q
scat-part
/04>n (1,2)
X=0.55
n (1,2) = 0.2 (from table 4)
'scat-part
= 63
X=0.55
'scat-part
= 67
X=0.4
Similarly,
Q
scat-part
= 60
X=0.7
346
-------
For Qscafs°4» the Sl*e distribution has an assumed mass median diameter
of 0.3 wn and og of 2. Thus,
'scat-SO,
= 28.7 nT/s
n (0.3,2) = 1.6
47.8
X * 0.4
Similarly,
*scat-SO
19.5
4X=0.7
Optical thickness (T) calculations are made using the equation
scat-part
and
^scat-part + ^scat-SO,
Taerosol
uH
m
where ozu « 322 m2/s and uHm * 4000 m /s
347
-------
Below are the tabulated values for T f or particulates, general haze,
and NO^ shown as a function of wavelength.
0.4 un 0.55 un 0.70 un
Tpart 0.083 0.078 0.074
Taerosol ).0287 0.0229 0.0199
TNO 0.429 0.078 0.00426
E.I. 4 Phase Function Calculations
The wavelength, scattering angle, and particle-size-dependent phase
function calculations are performed next.
b (X= 0.55 un) =
6X1 rvO
= °-55) = 0-0-3 km"1
bscat(X = 0.55 un) = 0.95 b
ext
bscat(X = 0.55) = 0.022 km
-1
rvQ = 170 km
348
-------
bap = °'05 bext
bap = 0.0012 km"1
bR(X = 0.55) = (11.62 x lO'V1) exp (-
Z = 940 m
bR(X = 0.55) = 1.0 x 10"5 m"1 = 0.010 km"1
bsp(X=0.55)=bscat-bR
bsp(X = 0.55) = 0.012 km"1
The attribution of bsp to coarse and fine particles in 1/3 : 2/3 pro-
portions gives:
bsp-coarse * °-004
"sp-submicron = °-008
Wavelength dependence is calculated as before, using:
349
-------
where
"coarse
nsubmicron 1>6
"Rayleigh = 4-1
"average
The wavelength-specific bsp values thus calculated are shown in table E-4
along with phase functions calculated for Rayleigh scattering according to
p(e) = 0.75 [1 + cos20] for all X
and extracted from appendix B for Mie scattering by coarse (DG = 6 im) and
fine (DG = 0.3 wn) mode particles.
Average p(X,0) values are calculated according to
b (X) • p(X,9)
Rayleigh,
coarse,
fine
p(X,0)|
I background ^r^ b (X)
/ ^ sp
Rayleigh,
coarse,
fine
Plume phase function values have also been taken from appendix B, for
DG = 1 wn and og = 2.
350
-------
TABLE E-4. PHASE FUNCTIONS AND SCATTERING COEFFICIENTS FOR
BACKGROUND AND PLUME
Phase Function p(X,e)
for Indicated 9
Scattering Component X (un) b^rat (km'1) 36" 90" 130°
BACKGROUND
Rayleigh Scattering
Due to air molecules 0.40 0.037
at site elevation 0.55 0.01 1.24 0.75 1.06
(n = 4.1) 0.70 0.0037
Mie Scattering
Submicron aerosol 0.40 0.013 2.87 0.276 0.157
DG = 0.3 in 0.55 0.008 2.90 0.318 0.189
ag = 2.0 0.70 0.005 2.88 0.357 0.211
(n = 1.6)
Mie Scattering
Coarse aerosol 0.40 0.004 1.56 0.147 0.0552
DG = 6 wn 0.55 0.004 1.44 0.161 0.0529
oq = 2.0 0.70 0.004 1.61 0.167 0.0825
(n - 0)
Total (average) 0.40 0.054 1.66 0.591 0.768
0.55 0.022 1.88 0.486 0.560
0.70 0.013 1.96 0.402 0.408
PLUME
DG = 1 pm 0.40 2.22 0.203 0.159
og = 2 0.55 2.45 0.219 0.142
0.70 2.58 0.224 0.156
351
-------
E.I.5 Calculating Plume Contrasts
Impacts are calculated for the range of scenarios described below.
To eliminate repetition, only the impacts on the view to the west (A} =
270°) are presented here.
Azimuth = A! = 270°
a= 36°
QM = 130°
ofe = 37°*
x = 60 km1"
Stable plume conditions:
0.429 X = 0.40 vm
= O.Q78 X = 0.55
0.004 X * 0.70
0.083 X = 0.40 un
rn.rt = 0.078 X = 0.55
p 0.074 X = 0.70
As p (X,9) values are given in appendix B only for even degree values of
6, subsequent calculations assume a 6A = 36°.
* For each transport/azimuth scenario, x is taken to be the transport
distance to the intersection of the plume centerline and the line of
sight.
352
-------
(Sulfate is not considered for the stable plume scenarios.)
Values of PD-|ume are taken from appendix B:
background
0.40 un
0.55
0.70
= 0.95
M
130°
0.159
0.142
0.156
Scenario
e
N
90°
0.203
0.219
0.224
A
36°
2.22
2.45
2.58
The value of bfix^ is determined by summing the values for b (units of
km"*) shown below:
bsp-submicron bsp-coarse bap bext
0.40
0.55
0.70
0.037
0.010
0.004
0.013
0.008
0.005
0.004
0.004
0.004
0.001
0.001
0.001
0.055
0.023
0.014
Also, for calculating sky/terrain contrast reduction:
rQ = 55 km
C0 = -0.9
fobj
From terrain elevation plot (figure E-3a) .
i.e., the entire plume is assumed to be between the mountains of view 1
and the Visitors' Center.
353
-------
Intermediate calculations are made for the following parameters:
,1
Tpart
TN02 * Tpart
0.162
0.501
0.946
X = 0.40 vtn
X = 0.55
X = 0.70
TNO« * Tpart
-------
Scenario IB—Morning, X = 0.40;
f-
C , = -0.187
plume
Scenario lC--Morninq, X = 0.70:
W = [((6!406)(69«) -1! f - exp(-O.K4)l jexp [(-0.014) . (20)1 )
L JL J v L j;
C , = -0.059
plume
E.I. 6 Calculating Reduction in Sky/Terrain Contrast Caused By Plume
Using the above data, we calculate ACr according to:
Scenario 1A— Morning, X= 0.55 un:
ACr = -(-0.9) exp [-(0.0230) • 55] J 1 - (,0.ig.f + 1) ***[l ' (0.26S)] |
ACr = 0.031
Scenario IB—Morning, X = 0.40 ym:
tfr = -(-0.9) exp[-(0.055)(55)] 1 - (.0>lfl^ ^ !) exp[-l • (0.87)];
AC - 0.021
Scenario 1C—Morning X = 0.70 ym:
tCr = -(-0.9) exp[-(0.014)(55)] 1 - (.0t0L + 1} exp[-l • (0.134)]
\ — *•
tC = 0.030
r
355
-------
For the stable transport situation, we may summarize our results for
the morning view toward the weist as shown:
'plume
0.40 -0.187 0.021
0.55 -0.127 0.031
0.70 -0.059 0.030
These values indicate that though significant reduction in visual range is
not expected (|ACr| < 0.1), a perceptible yellow-brown plume is likely to
be visible in some situations (|Cplume| > 0.1).
E.I.7 General Haze Effects
The same values for many parameters are used for assessing general
haze effects. Aside from the differences in calculated values for optical
thickness, the principal differences are
Tplume = Taerosol ' °-0229
rp = 50 km
fobj = ro/10° to" = °-55
0) = 1
For the westerly morning view at 0.55 wn, we have
= [•(0?S60)(o!$S) ' l] f1 - exp(-0.0229)] [exp(-0.0230 • 50)]
= -0.005
356
-------
Also,
tfr = -(0.9)[exp(-0.023 • 55)] [l - _QM\ + 1 exp (-0.55 • 0.0229)]
= 0.002
E.I.8 Comparison of Results with Reference Tables
The example described above corresponds reasonably closely to the
hypothetical 500 Mwe power plant of appendix D, as shown in table E-5.
TABLE E-5. COMPARISON OF EXAMPLE POWER PLANT EMISSIONS AND
APPENDIX D POWER PLANT EMISSIONS
Emissions
Hypothetical 500 Mwe Example Power Plant
Power Plant
Qpart (MT/day) 1.6 2.2
QNO (MT/day) 14.5 10.4
QSOX (MT/day) 29.0 32.8
The scenario descriptions, though somewhat different, are still close
enough to provide useful results, as shown in table E-6.
TABLE E-6. COMPARISON OF SELECTED SCENARIO DESCRIPTORS
Appendix D Example
RH 40% 40%
[^background °-04 PP"1 °-05
Simulation date/time 23 September/1000 21 December /0900
Scattering angle * 90° 130*
Wind speed 2.5 m/s 2 m/s
Background visual range 100 and 200 km 170 km
357
-------
At a downwind distance of 50 km, with a 200 km visual range, appendix
D shows a blue-red ratio of 0.892, which indicates that the plume would
probably be perceptible. This agrees quite favorably with the hand cal-
culated value of 0,86$. The modeled plume contrast of -0.031 at 0.55 un
is significantly lower than the hand calculated value of -0.13. This is
due to the differences in input parameters between the hand calculation
and the model. Also, the hand calculation procedure is conservative for
this backward scatter case (e = 130°) since multiple scattering is
ignored. The AE(L*a*b*) value of 4.5 (dropping to 3.37 by the 75 km down-
wind distance) indicates a marginally perceptible plume. Visual range
reduction is insignificant at 0.6 percent, a result which agrees with the
hand calculation showing ACr of 0.031 at 0.55 vm.
The downwind effect profiles shown in the plots in appendix D
indicate that, at downwind distances of 50 to 75 km, model results are
relatively insensitive to downwind distance for all parameters except
blue-red ratio, which peaks fairly sharply at approximately 25 km. The
difference in the blue-red ratio plots between the 2.5 and 5 m/s scenarios
indicates a substantial sensitivity to wind speed, a factor that con-
tributes to the difference in the magnitude of results between the hand
calculations and appendix D results. The assumption of 100% NO-N02 con-
version also contributes to this difference.
In general, the results above indicate a potential concern only for
the visibility effects of NOX emissions from the proposed facility. Par-
ticulate and S02 emissions appear unlikely to cause perceptible impairment
of visibility in either general haze or coherent plume scenarios.
Additional (level-3) analysis is probably warranted for this
facility, if design parameters (specifically NOX emissions rates) remain
as originally stated. In particular, the significance of potential
effects can be better evaluated given a more thorough analysis of the fre-
quency of occurrence of meteorological regimes associated with perceptible
impacts in and around the class I area, and a more precise determination
of anticipated NOX chemistry in the plume.
358
-------
E.2 EXAMPLE 2— CEMENT PLANT AND RELATED OPERATIONS
A cement plant has been proposed, along with related quarrying,
materials handling, and transportation facilities, for a location 20 km
away from a class I area. Terrain in the vicinity is relatively flat, and
no external vistas from the class I area (a national park) are considered
integral to park visitors' experiences. Visibility within the park
boundaries is of concern, however.
The proposed project would cause both elevated emissions from
numerous process points and ground-level emissions of fugitive dust.
Estimated emissions rates and particle-size distributions are shown in
table E-7.
For the level-1 screening, a downwind distance (x) of 20 km is used,
along with the corresponding az, for F stability of 46 m. As before, the
calculations are carried out in sequence.
E.2.1 Level-1 Analysis
p = ™* x - 20 km
oz = 60 m
p = 1.67 x 105
Tpart ' 10~6 P • %art
Qpart = 4-93 NT/day*
( = 4.54 + .395)
For the initial screening, it is conservatively assumed that the
emissions are released from a common point.
359
-------
TABLE E-7. ESTIMATED PROJECT EMISSIONS
Emissions Emissions Rates
Particulate Matter
Process Sources 0.395 MT/day
(effective stack height - 50 m)
DG = 1 un
°g = * i
p = 2 gm/cnr
Fugitive Emissions 4.54 MT/day
DG = 10 mi
= 2 i
= 2 gm/cnr3
Sulfur Oxides . 7.26 MT/day
(effective stack height = 50 m)
Nitrogen Oxides 2.72 MT/day
(effective stack height = 50 m)
360
-------
Tpart
0.822
TNO = 1.7 x 1CT7- p • QNO
0NO =2.72 MT/day
TN0 = °'0771
Taerosol = l-06 x 10~5 * r
vO * Wpart + 1-31 ' %02:
Taerosol = °-00918
FVQ = 60 km
Qpart * 4-93
Qso2 = 7-26
Tpart TNO,
exp -0.78 x/r
vO
Ci = -0.0392
Co =
1 -
A i. i exp (- T .
u, + 1 K ^ part
(-1.
exp (-1.56
Co = 0.343
C3 = 0.368 [1 - exp (-Taerosol)]
Co = 0.00336
Taken from figure 12, text page 56, for the proposed location.
361
-------
The values for Cj, C2, and C3 are characteristic of major participate
sources with relatively low NOX and SOX emissions. Both Cj and €3 (N02
discoloration and general haze indicators) are sufficiently low to indi-
cate relatively little possibility of perceptible impact. However, C2
indicates the potential for a perceptible particulate plume. It should be
noted, however, that the level-1 calculations were based on the following
two specific conservative assumptions:
> All particulate emissions are assumed to have been released
from a common point, resulting in the creation of a single,
coherent plume. Most of these emissions are, in fact,
fugitive emissions released near ground level.
> Particle scattering efficiency is assumed to be sig-
nificantly higher than would be expected for the OG = 10 un
fugitives.
Because level-1 procedures cannot address these issues, a level-2 assess-
ment is indicated. It is worth noting, however, that plume discoloration
resulting from N02 is unlikely, as are problems associated with general
haze. Therefore, the level-2 analysis need only concentrate on those
parameters related to estimation of particulate plume effects.
£•2.2 Level-2 Analysis
An analysis similar to that shown for example 1 (section E.I.2.2}
indicates that a D stability 1 m/s wind speed scenario corresponds most
closely to the 1-percentile worst-case diffusion. Because there are no
terrain features that might affect the flow of pollutants toward the park,
the transport distance for analysis remains at 20 km. Therefore, as az
for stability class D at 20 km is 200 m, the reasonable worst-case
value is 200 m2/s.
362
-------
The park itself is also relatively flat, with sizable (20 km)
internal open vistas. Because all internal vistas are potentially
impacted at all times of the day, scattering angles between 0° and 180°
are of potential concern. A range of angles covering backscatter, forward
scatter, and side lighting of the plume are selected for analysis.
As a means of simplifying the level-2 screening calculations, it is
assumed (as in level-1) that for calculation of visibility impacts, all
emissions are released from a common point. General haze has been
eliminated in the level-1 screening; therefore, SOX emissions need not be
considered, because the level-2 procedures do not incorporate short-term
sulfate formation. N02 formation, on the other hand, must be considered,
because of the effect of N0 on plume perceptibility.
Particulates constitute the major potential problem for the proposed
project, as indicated by the C,2 value of 0.343. There are two major
groups of particulate emissions, each of which warrants separate treat-
ment. Process emissions constitute a relatively small proportion of the
total mass emissions rate (< 10%); however, their size distribution (DG =
1, aq = 2) has a much greater scattering efficiency than the larger, fugi-
tive emissions (DG =10 or - 2). To distinguish between these emissions
types, the calculations below have various parameters that are subscripted
"proc" and "fug", to indicate the process (fine) emissions and fugitive
(coarse) emissions, respectively.
The calculations of particulate impacts begin with determination of
plume optical depth, based on the equation
This example is based, in part, on cement plants, which will typically
have bag-house controlled process emissions (and therefore no coarse
particle emissions) and fugitive emissions, which are generally large
particles. Fugitive emissions result from materials handling,
quarrying, haul roads, and so on.
383
-------
^scat-part
bscat/v
Both Qpart and bscat/v take different values for the different types of
emissions. Therefore Qscat-Part is determined separately for each type of
emissions.
Qpart-proc = °-395
DG
proc * H
proc = 2
•in
*
Pproc = 2 gm/cm
-------
less conservative meteorological scenarios of this level-2 analysis and
the lower scattering efficiency of large particles result in calculated
effects below perceptible levels, then no purpose is served by projecting
settling effects. Should potential effects be projected under assumed
conditions, then the decision can be made either to rework the level-2
analysis with consideration for settling or to go to a level-3 analysis.
Consideration of table 4 also indicates a possible simplification of
calculations. Because of the size of particles emitted, there is little
wavelength dependence of scattering coefficients. Therefore, we may
restrict consideration of scattering effects to a single wavelength,
X = 0.55 vm.
Proceeding with the analysis, we have:
6.17 Q
CHOJ
0 U X
QNO = 2.72 MT/day
c^u = 200 m2/s
x = 20 km
[NOX] = 0.0042 ppm
Even at extremely low background [03], it should be assumed that total
conversion of NO to N02 will occur at concentrations below 0.02 ppm.
Therefore,
[N02] = 0.0042 ppm
365
-------
Continuing, we have:
TNQ2 = 0.398 [N02] (babs/ppm)
babs/PPm|o.55 = °'31
TNO = o.oio
As stated previously, sulfate impacts need not be considered. Therefore,
we need consider only T_art.
^scat-part
(2«)1/2azu
_ "scat-part proc * ^scat-part fug
^scat-part proc = n-5 m /
^scat-part fug = 10-5 m2/
= 200 m2/s
Tpart = °-0439
bext (X=0.55 un) =
vO
rvQ = 60
bext|0.55 = °'065
bscat
bscat = °-°62 km"1
366
-------
bsp = bscat - bR
="1.06 x 10'V1
z = 400 m
^0.011 km"1
bsp = 0.051
=0.67 b«.n = 0.034 km'1
ron ***
b«.n = 0.33 b«.n = 0.017 km'1
spcoarse sp
Phase functions are determined for the background air mass and the plume
at scattering angles of 22°, 44°, 90°, and 136", as shown in table E-8.
Because of the assumed bimodal particle-size distribution, average values
for the plume phase function are calculated. These plume average values
are weighted using the values of Qscat-Part proc and ^scat-part fug
according to the equation
Pl*»0) av plume =
Qscat-part proc P(X* 9)proc * Qscat-part fug p(x* 9)fug
^scat-part proc * ^scat-part fug
Finally, we determine Cp]ume and ACr using the following values:
o = 90°
Tpart ' °-044
TN02 • °-010
367
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TABLE E-8. BACKGROUND AND PLUME ATMOSPHERE PHASE FUNCTIONS AND
SCATTERING COEFFICIENTS (X= 0.55 un)
Background Atmosphere
Scattering Component bscat (km"i) 22°
„-!•
Rayleigh Scattering
Due to air molecules
at site elevation
0.011
1.39
Phase Function p( X,e)
for Indicated 0
44*
1.12
90°
0.75
136°
1.125
Mie Scattering
Submicron Aerosol
DG = 0.3 un
og = 2.0
Coarse Aerosol
DG = 6 un
o = 2-0
0.0-34
0.017
5.36
3.20
2.01
1.08
0.318
0.160
0.188
0.0740
Total (average)
0.062
4.06
1.60
0.351
0.323
Plume Scattering
DG = 1 un
Phase Function p(x,0)
for Indicated 0
Component
Process Emissions
^scat-oart
11.5
22°
5.92
44°
1.57
90°
0.218
136°
0.175
Fugitive Emissions
DG = 10 un
10.5
2.70
1.28
0.138
0.0344
Plume average
22
4.38
1.43
0.180
0.108
368
-------
TN02 + Tpart
Tplume = sT?T~a ' ®'
054
ext
r = 5 km
C - -0.9
obj
Tpart
TN02 * Tpart
= 0.814
"bkg *
0.95
Cplume anc* ^r are determined according to;
'plume
plume
(pu)
- 1
bkg
(-bextro)
exp-br
1 -
("Tp1umel
1
(-bextrp)
'Pi
On the basis of these equations, and the p(X, e) from table E-8, we com-
pute the impact projections shown in table E-9.
369
-------
TABLE E-9. PROJECTED PLUME CONTRAST AND CONTRAST REDUCTION
FOR EXAMPLE 2 (X = 0.55 wn)
Scattering Angle (0)
Slume
These results show that visibility impacts would probably be imper-
ceptible for the situation described. Therefore, further analysis is not
warranted. Note that the combined effects of the less conservative
meteorology (D,l versus F,2), the consideration of particle-size distribu-
tion, and the more precise formulation of visibility impact parameters in
level-2 have provided a substantially different description of expected
impacts from that which might be extracted from the level-1 results.
22°
-0.003
0.032
44°
-0.009
0.028
90°
-0.023
0.020
136°
-0.029
0.016
370
-------
REFERENCES
Altshuller, A. P. (1979), "Model Predictions of the Rates of Homogeneous
Oxidation of Sulfur Dioxide to Sulfate in the Troposphere." Atmos.
Environ., Vol. 13, pp. 1653-1661.
Briggs, 6. A. (1972), "Discussion on Chimney Plumes in Neutral and Stable
Surroundings." Atmos. Environ., Vol. 6, pp. 507-610.
Briggs, G. A. (1969), "Plume Rise," U.S. Atomic Energy Commission Critical
Review Series, TID-25075, National Technical Information Service,
Springfield, Virginia.
Briggs, G. A. (1971), "Some Recent Analyses of Plume Rise Observations,"
Proc. of the Second International Clean Air Congress, H. M. Englund
and W. T. Berry, eds., (Academic Press, New York, New York), pp.
1029-1032.
Dixon, J. K. (1940), "Absorption Coefficient of Nitrogen Dioxide 1n the
Vtsitle Spectrum," J. Chem. Phys.. Vol. 8, pp. 157-160.
Duffle, J. A., and W. A. Beckman (1974), Solar Energy Thermal Processes.
(John Wiley and Sons, New York, New York).
Holzworth, G. C. (1972), "Mixing Heights, Wind Speeds, and Potential for
Urban Air Pollution throughout the Contiguous United States," AP-101,
Office of Air Programs, Environmental Protection Agency, Research
Triangle Park, North Carolina.
Land, E. H. ,(1977), "The Retlnex Theory of Color Vision," Sci. Am.,
Vol. 237, pp. 108-128.
Latimer, D. A., et al. (1978), "The Development of Mathematical Models for
the Prediction of Anthropogenic Visibility Impairment," EPA-450/3-78-
llOa, b, and c, available from NTIS as PB 293118 SET.
Latimer, D. A., T. C. Daniel, and H. Hogo (1980), "Relationships between
A1r Quality and Human Perception of Scenic Areas," Publication no.
4323, American Petroleum Institute, Washington, D.C.
371
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Latimer, D. A., et al. (1980a), "Modeling Visibility," invited paper
presented at American Meteorological Society/Air Pollution Control
Association, Second Joint Conference on Applications of Air Pollution
Meteorology, 24-27 March, New Orleans, Louisiana.
Latimer, D. A., et al. (1980b), "An Assessment of Visibility Impairment in
Capitol Reef National Park Caused by Emissions from the Hunter Power
Plant," EF80-43, Systems Applications, Incorporated, San Rafael,
California.
Liu, M. K., and D. R. Durran (1977), "The Development of a Regional Air
Pollution Model and Its Application to the Northern Great Plains,"
EPA-908/1-77-001, U.S. Environmental Protection Agency, Region VII,
Denver, Colorado.
Malm, W. C., et al. (1979), "Visibility in the Southwest," unpublished
manuscript.
Middleton, W.E.K. (1952). Vision Through the Atmosphere (University of
Toronto Press, Toronto, Canada
Randerson, D. (1972), "Temporal Changes in Horizontal Diffusion Parameters
of a Single Nuclear Debris Cloud," J. Appl. Meteor., Vol. 11,
pp. 670-673.
Schulz, E. J., R. B. Engdahl, and T. T. Frankenberg (1975), "Submicron
Particles from a Pulverized Coal Fired Boiler," Atmos. Environ., Vol.
9, pp. 111-119.
Singh, H. B., F. L. Ludwig, and W. B. Johnson (1978), "Tropospheric
Ozone: Concentrations and Variabilities in Clean Remote Areas,"
Atmos. Environ., Vol. 12, pp. 2185-2196.
Trijonis, J., and D. Shapland. (1979), "Existing Visibility Levels in the
U.S.," EPA-450/5-79-010, U.S. Environmental Protection Agency,
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372
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Whitby, K. T., and 6. M. Sverdrup (1978), "California Aerosols: Their
Physical and Chemical Characteristics," ACHEX Hutchlnson Memorial
Volume, Particle Technology Laboratory Publication Number 347,
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Williams, M. D., E. Treiman, and M. Wecksung (1980), "Plume Blight
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373
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4. TITLE AND SUBTITLE
WORKBOOK FOR ESTIMATING VISIBILITY IMPAIRMENT
TECHNICAL REPORT DATA .
(Please read Instructions on the reverse before completing/
. REPORT NO.
EPA-450/4-80-031
2.
3. RECIPIENT'S ACCESSION NO.
5. REPORT DATE
November 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Douglas A. Latimer and Robert G. Ireson
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Systems Applications, Inc.
950 Northgate Drive
San Rafael, California 94903
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-0337
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Air Quality Planning and Standards
U. S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This workbook is designed to provide three screening procedures to assist in
determining the potential impacts of an emissions source on a Federal Class I area's
visibility. It does not address the cumulative impacts of multiple sources on
regtonal haze. A level-1 analysis involves a series of conservative screening tests
to eliminate sources with little potential for visibility impairment during hypo-
thetical worst-case meteorological conditions. If impairmeet is indicated, a more
resource intensive level-2 analysis is warranted. If both analyses indicate impairment
a level-3 analysts using a plume visibility model should be used. Two example-
applications are provided; for a coal-fired power plant and a cement plant.
17.
KEY WORDS AND DOCUMENT ANALYSIS
a.
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Atr Pollution
Meteorology
Atmospheric Diffusion
Air Quality Modeling
Visibility
Sulfates
Aerosols
New Source Review
Point Sources
13 B
4 A
4 B
18. DISTRIBUTION STATEMENT
RELEASE TO THE PUBLIC
19. SECURITY CLASS (ThisReport)
None
21. NO. OF PAGES
390
20. SECURITY CLASS (Thispage)
22. PRICE
Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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