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 1Coal -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 2Cement 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

-------
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

-------
    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

-------
     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

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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
     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

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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

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                                 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

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       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-

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 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

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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.

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 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-

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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.

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                               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

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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

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     >  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

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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

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(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):

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                     .     * .
                   ~ 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 
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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

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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

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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

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            It  !h
              * 'h-plume + Vh [*><-btpo>] 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

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    >  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

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                                              LINE OF  SIGHT
DEMISSIONS
  SOURCE
                          ^OBSERVER
        Figure 5.   Plan  view  of observer-plume geometry.
                            28

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       OBSERVER
                                                   PLUME
                                                 CROSS-SECTION
                                    GROUND
Figure 6.  Elevation  view of observer-plume geometry
                    29

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                               -  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

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     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

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    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)   tJA   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

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                                           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:

                         dso.
                         -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

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O1
                     Figure 13.  Regional background visual range values (rvo) for use in level-1
                                 visibility screening analysis procedure.

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     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

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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

-------
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

-------
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

-------
     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

-------
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

-------
                      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 tynthii
   (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

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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

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            11.25
     -EMISSIONS SOURCE
                                                 OBSERVER A
                              PLUME MATERIAL
Figure 22.   Observer-plume orientation for level-2
            visibility screening analysis.
                     96

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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

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                                                               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

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        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 analysisa 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

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             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

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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

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     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

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 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

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                                   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

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            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

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                                                         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

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        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

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 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

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                             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

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     >  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

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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

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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

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                          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

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                      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 uHm 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

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     >  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

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               days


           (a)   Winter
                                                days


                                            (b)  Spring
15
                  days

               (c)  Sunnier
                                                                          20
 Figure 29.
                                *               days

                                            (d)  Autumn


n^lt?K?f Jred1cte? frecuency 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

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          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

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        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

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         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

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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

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     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;
flfl9o5ftoo
4.4799E+00
4.4(|63EtOO
       +0
4.3263E+00
4.2389EtOO
4.1367E+00
4.0217E+00
  8963EtOO
  ,7627EtOO
  ,6228*00
 ,4787EtOO
 .3319tOO
     I UT V V
tf,cu3EtOO
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*3485E01
7.8799E.01
7.447JE.01
7.0490E-01
6,6833E01
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
                                 4,0070E01
                                 3,98BE01
                                 3.979JE-01
                                 3.9784E.OI
                                 3.9BS4E.01
                                 4,0202E*01
                                 4,046601
                                 4,078lEOt
                                  ,
                                 4,1544E01
                                 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*08EOl
                                 4.6083E.01
                                  ,
                                 4,8975E01
                                 4.9388E-01
                                 4,9772E.01
                                 5,0120E*01
                                 5,0424E*01
                                 5.0675E-01
                                 5,0862E01
                                 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
3,7oJ9tOO
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
2,1436E01
 MAa^.e>M<
 ,
2.0444E-01
2.0073E.OI
'.9775E-01
 ,9538EOt
 ,9355E.Ot
 .9130E-0!
 . - - * u - V i
 .9105E.01
 .9176E-01
 ,9JOOE01
 .9473E.0.1
 ,9687E01
,,9933E.01
2,0198E01
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
6,4889tOO
6.2203E+00
5.9309E+00
5.6262tOO
5,3l89*00
5.0084E+00
4.7009E+00
       4.1084tOO
       3,0638iOO
       2.8370E+00
       2,6245*00
       2,4261tOO
       2,24l5tOO
       2,0703E*00
        .7650R+00
        .6294E+00
        .3885E+00
        ,28|9EfOO
        ,!837EtOO
       l,0108tOO
       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
       496131E0}
       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
                                    2,557b01
                                    2,5068*01
                                    2,4664.01
                                    2,4361.01
                                    2.3935E-01
                                    2,3818.01
                                    2.3759C.01
                                    2,3750.0l
                                    2,3790.01
                                    2,3876E01
                                    2,4008.01
                                    2,4166E01
                                    2,4407*01
                                    2,46660t
                                    2.4959E-01
                                    2,5276.oi
                                    2,5609oi
                                    2.5947E-01
                                    2,628001
                                    2,660501
                                    2,692001
                                    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
                                3.2806E01
                                3.19Q7E.01
                                3,1132*01
                                3,0471E*01
                                2.9917E-01
                                2.9403E-01
                                2,9099E.01
                                2,6820C*01
                                2,66160t
                                2,648|.ot
                                2.8395E-01
                                2.8436E-01
                                2,6526E.01
                                2,6669E01
                                2.6652E.01
                                2,9075E01
                                2.9331E.01
                                2.961SE.01
                                2,9922E01
                                3,0247.0l
                                3,056SE01
                                3.093JE-01
                                3.1263E.Q1
                                3.1642E*01
                                3,2006EOf
                                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
                               3,6103E01
                               3.6266E01
                               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
8,9228tOO
8.2342E+00
7.5621E+00
6.9175E+00
6.3078*00
5.7376E+00
5.2096E*00
4,7243EtOO
4,2806E*00
3,8764tOO
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
4t8a5lEOl
4.4898E.01
3,8549.0l
3.578501
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
  .-
  ,867601
  ,803001
  ,7459.01
  ,6979-01
 ,606601
 .5893E.OI
 ,5674-01
 ,5626E*01
 .5631E-01
 ,5701E01
 .5850E-01
 ,
 .6U02E-01
 .6786E-01
 .7211E.01
 .7658E.01
 ,8115E01
  u^u-T^wyj
  9003E.01
  9398E.OI
1.9739E.01
2.0027E.01
2.0289E.01
2,0560E01
2 AAA/lC_/i4
2,120701
2, 1569.01
2.2051E-01
2,2667E.oi
2.3613E-01
2.4884E.01
2.6418E-01
2,796501
2,9148.01
2,9596E01
                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
,9326E01
.9023E-01
.8601E.01
.8651E-01
(8565E01
,8527E01
,6527E*Ol
,8557C01
.8617E.01
,87i5g.oi
,886oEOi
.9060E-01
.9319E.01
,9635E-01
.9995E-01
!,0384E01
>,0779E01
!,1162E*01
i.isaoE.oi
,18,214U*01
>,2ai8E-01
,269E01
!,2992EOl
J.3341E-01
J.3779E.01
,43fllE01
!,5041E01
I.5855E-01
f,6707EOi
I.7477E.01
!,8022E-01
!,8220E01
                       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(XQ)
 3,37951.01
 3,20516-01
 3,0484E01
 2.9085E-01
 2.7843E-0!
 2.6743E-01
 2,5770E01
 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
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60,0
02,0
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66,0
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70,0
72,0
74,0
76,0
78,0
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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!
 ,6026E01
 ,5610E*01
 .5192E-01
 ,4542E*0!
 ,4410*0f
 ,4549.0l
 .5297E.O!
 ,549aE01
 ,5634E*01
 .5773E-01
 .5995E.01
 ,6369E0!
 ,697E0!
 ,7739E01
 .8707E.01
 ,9810E01
2,1010E01
2,225|EOI
2.3453E.01
2.4513E.01
2.5343E.01
2.5907E.01
2,6221E01
2,6337E0!
2.6363E-01
2,6504E01
2.70U1E-01
2,B24SE01
3,026E01
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
1.033li01
9.5278E+00
8,7372fOQ
7.9700E+00
7.2537E+00
6.5759E+00
5,3607EtOO
4,824l*00
4.3352tOO
3.89JOE+00
3,4952EtOO
3.1391E+00
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2,5383E*00
2,0570E+00
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1.6669E+00
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1.2172E+00
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136.0
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140.0
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                 172

-------
                       DG

                       X
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                           0.7 vm
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56,0
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60,0
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lt!202E*01
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-------
                     DG

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  2.7166E.01
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  2,03I9E01
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92.0
94.0
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6,45S3E01
                       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
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50,0
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J4,0
)6,0
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64,0
66,0
68,0
70,0
72,0
74,0
76,0
78,o
80,0
88,0
84,0
86',0
88,0
90,0

!*-
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
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
1.86280l
1.7669E.01
1.6786E-01
1.6063E.01
1.5509E.01
1.5061E-01
1.4693E.01
1,417E.01
1.4233E.OI
1.4092E.01
1,3922E01
1.3674JE-01
1,3401E01
1.3226E01
1,3214E01
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
14,0
16,0
18,0
20,0
22,0
24,0
26,0
26to
30.0
32,0
J,0
36,0
38|o
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
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,B76ttOO
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
 .642U + 00
 ,5o5<>EtOO
 ,2224fOO
 .0982E+00
8,0176E01
7.2439E-01
6,5781E01
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
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
2.1356E.01
2.0541E.01
1.9747E.01
l,8897f.ot
1.8033E.OJ
1.7274E.Q1
1,6708E01
1.6294E.01
1.5902E-01
1.5450E.01
1.4965E-01
1.4549E.QJ
1.4286E-01
.4183E01
.4203E.01
,432lE-Ot
.4548E.01
,4878E01
.5254E-01
,55B3E01
,5fl04EOt
.5952E-01
,6128E01
1.6458E-01
1.7023E-01
1.7822E-OI
i,8604E01
1.9950E-01
2,12740l
2.2758E-01
2,4328E01
2.5818E-01
2.7048E-01
2,7930E01
2.8452E.01
2,8662E01
2.8696E.01
2.872BE.01
2.9067E.01
3.0172E-01
3,2426E01
3.5778E.01
3,9b30C01
4,2906E01
4,4254E01
                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
 10.0
 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
2,1412f01
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,J33ltOO
                               e
2,B22E+00
2,183?E*00
 1.6B26EtOO
 1..5013E + 00
 1,3322E*00
 I,2l3lt00
 l,loT3tOO
T,4411E01
6.5327E-01
6,178fiE.Oi
4,92516-01
4.5052E.01
4,t562E.Ol
3.79JJE.01
3.4123E.01
3t095lE01
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
  ,
  ,5967E01
  ,49276.01
  .4230E.01
  .3846E-01
  .3435E.01
  .2933E.01
  ,2580E01
  .2472E-01
  ,2443E01
  ,238801
  ,2052EOl
  ,1516E.01
  .1200E.OI
  .1194E.01
  ,1315E01
  ,1670E01
 ,36Sl.01
 .5063E-01
 .5267E-01
 ,5578g.01
 .5959E.01
 .8413E.01
2,0772E01
2.36S2E-01
2,732iE01
3.172SE-01
 ,
3.9039E-01
4,2566E.Ol
4,6030E01
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
       3,2228tOl
       2.5005E+01
       1.9507E+01
       l,2536E+Oi
        .
      8,597E+00
      7.2296E+00
      6.1636E+00
      5,302tOO
      S.5710E+00
      3,l3784oo
      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
      12,0
      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
1,1205E01
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,3993tOO
 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
        6,6473E01
        6,6536E01
        5,5700E-01
        fl.6l99g.0l
        3.6784E-01
        3.6199E.01
        3.3127E.01
        2.7367E-01
        2.2102E-01
        2,17a7E.01
        2,230SE01
        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
                                      ,5698E01
                                      ,4065E01
                                      .4109E.01
                                      ,4722E01
                                      .3075E-01
  P *  W fc  ^ V 1
  ,0241E01
  .0693E.01
  ,2510*01
  ,364bfcbwvc.
                                      5672E-02
 ,1237E.01
 ,2433EQ1
 ,3612E01
 ,38326.01
 ,4608E*01
 ,6626E01
 ,955601
2,3148E*01
2.7975E-01
3,556401
4,3107E01
5.1053E-01
6.1903E-01
7,5079.01
-,v  w u. -w 
S.912UE.01
9.4776E-01
6,8497E01
6,236lEOt
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
        5.937Et02
        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
         ,3488tOO
         ,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
        3,39iE.Oi
        3.4Q18E.01
        2.5823E.OJ
        2.2744E.OJ
        i8408E.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)
 ,5174E01
 ,2810E01
 .1275E.01
 .0254E.01
 ,0532E01
9,75561.02
8.7953E.02
9,8605E02
8.9522E.02
8,5131E02
7.6283E.02
6,8a89E.02
7,8401E02
8.0501E-02
7.3009E.02
7.0228E-02
6.9672E.02
6,9512E02
5,0821E02
f i o e * f n ^
7,4026E*02
7,7631E02
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
 6,527E.01
 5.5942E-01
 a,S480E01
 4.6734E.01
 4.6117E-01
 3.7656E-01
 3.6795E-01
 3,06080i
 2.4464E01
 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
  *6,0
  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
3,346E+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
 ,0522tOO
9,4500E01
8,635201
7,7440*0|
6,3026|.01
5,0728.Q1
5.5583E.01
3.987U.01
3,3947.0l
3.1150E01
2,3358.0i
2.0913E.01
 ,7i600l
 ,39Q7OJ
 C2262.0|
 .1299E.Q1
              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
6,69Q5E02
5,4047E.02
4.6377E-02
,5968E02
4,5963E*02
4,597002
3.954U.02
4.2393E-02
 3.1168.02
 3,325002
 4,8081E02
 4,584S02
 493432E02
 6,137?.0?
 6,5830E02
 1.2595.0t
 292242E01
 3.4421E-01
 5.1661E.01
 7t6899g.01
 8.3350E-01
 5.7081E.OI
 6,2542.oi
 7,2376.0l
 7,524601
 1,4827E*00
 l,7329g*00
 9,1?3201
   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
 5,3666E02
 S.5367E.02
 5.S315E.02
 4.7693E.02
 4,8S07E02
 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
.4f2
.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
. KO
.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

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    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

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                  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

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       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

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       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
.766
.786
.833
.982
-.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

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       BACKGROUND VISUAL RANGE (KIT)  20O.0
       PLUHE-OBSERVER DISTANCE (KM)  4O.O0

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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
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.000
-.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
-.0t
-.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 inputfor particulates, S02, and NOX, respectivelywere 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
                                      175F
                                      353K
                                      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*AB#)
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
 ii
 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 ~rir  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     '   'I1  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
                                                          iii  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  ' QNX

* 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) . /,   283K \
         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 ConcentrationAccording 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 RangeTelephotometer 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 geometryFigure 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

          TQ  -  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  Qscafs4 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 IBMorning,  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 IBMorning,  X = 0.40  ym:





 tfr = -(-0.9)  exp[-(0.055)(55)]  1 - (.0>lfl^ ^ !) exp[-l  (0.87)];





 AC  -  0.021





Scenario 1CMorning  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

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                  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

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         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

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  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

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                                 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

-------
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,
     Research  Triangle Park,  North  Carolina.

Turner, D. B.  (1969),  "Workbook of  Atmospheric Dispersion  Estimates,"  U.S.
     Department of  Health,  Education, and Welfare,  Public  Health Service
     Publication No.  999-AP-26.
                                    372

-------
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,
     University of Minnesota, Minneapolis, Minnesota.

Williams, M. D., E. Treiman, and M. Wecksung  (1980), "Plume Blight
     Visibility Modeling with a Simulated Photograph Technique." J. Air
     Pollut. Contr. Assoc., Vol. 30, pp. 131-134.
                                   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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