xvEPA
             United States
             Environmental Protection
             Agency
             Air Pollution Training Institute
             MD20
             Environmental Research Center
             Research Triangle Park NC 27711
September 1978
EPA-450/3-78-106
             Air
APTI
Course 439
Visible
Emissions
Evaluation

Student
Manual
Fina

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   United States
   Environmental Protection
   Agency
Air Pollution Training Institute
MD20
Environmental Research Center
Research Triangle Park NC 27711
September 1978
EPA-450/3-78-106
APTI
Course 439
Visible
Emissions
Evaluation
               Final
 United States Environmental Protection Agency
 Office of Air, Noise, and Radiation
 Office of Air Quality Planning and Standards
 Research Triangle Park, NC 27711

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US/EPA
THIS IS NOT AN OFFICIAL POLICY AND STANDARDS DOCUMENT.
THE OPINIONS, FINDINGS, AND CONCLUSIONS ARE THOSE OF
THE AUTHORS AND NOT NECESSARILY THOSE OF THE ENVIR-
ONMENTAL PROTECTION AGENCY.

EVERY ATTEMPT HAS BEEN MADE TO REPRESENT THE PRESENT
STATE OF THE ART AS WELL AS SUBJECT AREAS STILL UNDER
EVALUATION.

ANY MENTION OF PRODUCTS OR ORGANIZATIONS DOES NOT
CONSTITUTE ENDORSEMENT BY THE UNITED STATES ENVIR-
ONMENTAL PROTECTION AGENCY.
                     ii

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svEPA
                                 AIR POLLUTION TRAINING INSTITUTE
                          MANPOWER AND TECHNICAL INFORMATION BRANCH
                             CONTROL PROGRAMS DEVELOPMENT DIVISION
                         OFFICE OF AIR QUALITY PLANNING AND STANDARDS
             The Air Pollution  Training Institute (1) conducts training for personnel working on
             the development and improvement  of state,  and local governmental,  and EPA air
             pollution control programs, as well  as  for personnel in industry and academic insti-
             tutions; (2) provides consultation  and  other  training  assistance  to  governmental
             agencies,  educational  institutions,  industrial-  organizations,  and  others engaged  in
             air pollution  training activities;  and  (3> promotes the development and improve-
             ment of air pollution training programs in educational institutions and state, regional,
             and local governmental air pollution control agencies.  Much of the program  is now
             conducted by an on-site contractor, Northrop Services, Inc.

             One of the principal mechanisms  utilized to meet the Institute's goals is the intensive
             short term  technical  training course.  A full-time professional staff is responsible for
             the design,  development, and presentation of these courses.  In addition the services
             of scientists,  engineers,  and specialists  from other  EPA  programs, governmental
             agencies, industries, and  universities  are used to augment and reinforce the Institute
             staff in the development and presentation of technical material.
             Individual  course  objectives and desired learning outcomes are delineated to meet
             specific program needs through training.   Subject  matter areas covered include air
             pollution  source studies, atmospheric dispersion, and air quality management.   These
             courses are presented in  the  Institute's resident classrooms and laboratories  and at
             various field locations.
             Robert G. Wilder
             Program Manager
             Northrop Services, Inc.
Q£sA~$&£&Usn£sr'
/[      .Mean J. Schueneman
       fr Chief, Manpower & Technical
           Information Branch
                                               ill

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FOREWORD
                   The Federal Government has discontinued the use of
                   Ringelmann Number standards in Federal new source per-
                   formance standards and has now based the determination of
                   the optical density,  or opacity of visible emissions from
                   stationary sources, solely on opacity.  Many State
                   regulations have not made this change and continue to
                   operate under a dual system in which Ringelmann Number
                   is used in the evaluation of black or gray emissions and
                   Equivalent Opacity is used in the evaluation of all other
                   visible emissions.

                   This manual is designed to serve as wide an audience as
                   possible and so continues to refer to both the Ringelmann
                   Number and the Equivalent Opacity methods of evaluation.
                   If opacity is now the only type of visible emission reg-
                   ulation in your State, please make the proper adjustments
                   in the manual curriculum to reflect this regulation.  If
                   Ringfelmann and Equivalent Opacity are currently viable
                   in your State, your trainees should at least be aware of
                   the Federal practice.  A copy of the current Method 9 as
                   published in the Federal Register is included in this
                   manual.

                   This manual is intended for those students who need to
                   become a qualified visible emissions evaluator for the
                   first time.  To become a qualified visible emissions
                   evaluator the student must successfully complete a train-
                   ing school, normally of three days duration presented by
                   a Federal, State or local air pollution agency, or

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educational establishment.  The training school
consists of a series of lectures, slide and film
presentations and the actual training of the students to
evaluate the opacity of visible emissions.  The first
half of the school provides sufficient background
material such that competent evaluations of the opacity
of visible emissions can be made in the field during
enforcement operations.  The second half includes the
qualification steps in reading visible emissions.
During the second half, students needing only recertifica-
tion can be included.  They need not repeat the first
half.

Batelle-Columbus Laboratories is creo. -d for most of
the material in this manual.  Under contact with EPA,
they prepared a training package.  Because there has
been much time elapsed since completion of their contract
and due to many changes in regulations and techniques,
EPA has found it appropriate to modify the package
prepared by Batelle.
                vi

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                                 CONTENTS                            Page
FOREWORD                                                               v
     COURSE OBJECTIVES                                               xi
     I.    VISIBLE EMISSIONS:   THEIR CAUSE AND REGULATION 	    1-1
    II.    PRINCIPLES OF COMBUSTION	    2-1
   III.    COMBUSTION OF FUEL  OIL - CORRECT PRACTICES  	    3-1
               Classification of Fuel Oil 	    3-1
               Oil Burner Types 	    3-3
               Boiler Types	    3-8
               Soot Blowing 	    3-9
               Black Smoke and White Smoke 	    3-10
               Particulates 	   3-11
               Sulfur Trioxide 	    3-12
               Control Equipment 	.	    3-13
    IV.    COMBUSTION OF COAL  AND ITS CONTROL  	    4-1
               Classification of Coal 	    4-1
               Basics of Coal Combustion and  Combustion
               Equipment 	    4-5
               Some Terms Used in Coal Combustion	    4-9
               Plume Visibility 	    4-11
               Mechanical Coal Firing Equipment	    4-13
               Causes and Control of Particulate Emission
               From Coal Combustion	    4-16
     V.    OTHER COMBUSTION EMISSIONS:   INCINERATORS,  AGRI-
          CULTURAL BURNING, NATURAL GAS,  AND  MOBILE SERVICES 	    5-1
               Solid Waste Disposal by Incineration	    5-1
               Agricultural Burning 	     5-7
               Combustion of  Natural Gas 	     5-8
               Engines Used in Transportation	     5-11
               Visible Emissions From Mobile  Sources  	     5-13
                                     vii

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                                                                    Page
  VI.    NONCOMBUSTICN EMISSIONS AND WATER VAPOR PLUMES 	      6-1
             Metallurgical Furnaces 	      6-1
             Driers 	      6-4
             Terminology in Metallurgical Processing 	      6-5
             Iron and Steel Mills 	,	      6-7
             Gray Iron Foundaries	      6-12
             Non-Ferrous Metallurgical Industry	      6-13
             Petroleum Refineries 	      6-15
             Portland Cement and Lime Plants	      6-17
             Kraft Pulp Mills	      6-19
             Sulfuric Acid Manufacturing 	,  . , .      6-20
             Nitric Acid Plants 	      6-22
             Paint and Varnish Manufacturing 	      6-23
             Hot-Mix Asphalt Batching Plants ,	      6-24
             Phosphoric Acid Manufacture 	      6-26
             Phosphate Fertilizer Manufacture 	      6-28
             Soap and Synthetic Detergent Manufacture 	      6-29
             Wet Plumes	      6-30
 VII.    CLASSIFICATION AND IDENTIFICATION OF SOURCES ,...	      7-1
             Classification	      7-1
             Identification 	      7-3
VIII.    RINGELMANN CHART AND EQUIVALENT OPACITY 	      8-1
             The Ringelmann Chart 	      £-5
             Smoke Reading Aids 	      8-7
             Training of Inspectors 	      8-10
             Problems of Reading Smoke in the Field 	      8-12
             Advantages of Visible Emission Regulations 	      8-15
  IX.    QUALIFICATION PROCEDURES AND EXERCISE IN RECORDING FOR
        QUALIFICATION 	      9-1
             Instructions to the Student During the
             Reading of Smoke	,,	      9-2
             Filling Out the Training Form	      9-4
                                   viii

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   X.   BASIC METEOROLOGY                                           10-1
             Primary Meteorological Factors Affecting
             Concentration of Air Pollutants                        10-1
             Wind                                                   10-2
             Pressure Gradient Force                                10-6
             Coriolis Effect                                        10-7
             Topographical Features                                 10-10
             Stability                                              10-11
             Solar Radiation, Precipitation, and
             Humidity                                               10-27
             Topography                                             10-28
             Sky Condition                                          10-28
  XI.   LEGAL ASPECTS OF VISIBLE EMISSIONS 	        11-1
             History and Test Cases 	        1.1-1
             Equivalent Opacity and Smoke Emission
             Laws 	        11-4
             Local Regulations 	        11-6
             How to be an Expert  Witness..-...-	        11-6
 XII.   OBSERVATION REPORTS FOR VIOLATIONS 	        12-1
             Special Designations	        12-4
XIII.   EMISSION GENERATOR 	        13-1
             Mark II Smoke Generator 	        13-1
                  Black Smoke 	        -13-1
                  White Smoke 	        13-2
                  Transmissometer 	        13-2
                  Conduct of the School 	        13-4
                  Other Smoke Generating Equipment 	        13-4
                                  ix

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                                                                    Page

 XIV.   OPACITY PROBLEMS CAUSED BY WATER VAPOR 	        14-1

             Visible Identification of Water Vapor Plumes ...        14-3

             Typical Operations Which Discharge Water
             Vapor 	        14-5
             Methods of Eliminating Visible Wet Plumes 	        14-6

             Reading Water Vapor Plumes 	        14-8

             Description of the Psychrometric Chart 	         14-9

             Example of the Use of the Psychrometric
             Chart 	        14-14

  XV.   U.S. EPA METHOD 9 - VISUAL DETERMINATION OF THE
        OPACITY OF EMISSIONS FROM STATIONARY SOURCES
        (40CFR Part 60 Appendix A) 	        15-1

 XVI.   FEDERAL STANDARDS OF PERFORMANCE FOR NEW STATIONARY
        SOURCES (SUMMARY) 	        16-1

XVII.   VISIBLE EMISSION STANDARDS OF THE UNITED STATES 	        17-1
                                   x

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COURSE OBJECTIVES
                    This manual is intended for use by students that have
                    not been certified as a qualified observer.  The con-
                    tents of this manual will provide the qualified observer
                    with adequate background knowledge needed to help sub-
                    stantiate any violation that.he.may record.
                    At the conclusion of this course the student should be
                    able to:
                         (1)   Visually measure  (i.e., without the use of
                               devices), the shade or opacity of visible Air
                               pollution emissions for a set of 25 shades
                               of white smoke and 25 shades of black smoke:
                               (a)   With an average error not to exceed
                                     7.5 percent opacity in each, category.
                               ("b)_   With an error not to exceed 15%
                                     opacity (or 3/4 of a Ringelmann
                                     Number), on any one reading in
                                     each category.
                               Define Ringelmann Number and Equivalent
                               Opacity in the following manner:
                               (a).   The Ringelmann Number gives shades of
                                     gray by which the density of columns
                                     smoke rising from  a source may
                                     be compared.  It is a system whereby
                                     graduated shades of gray, varying by
                                     five equal steps between white and
                                     black, may be accurately- reproduced
                                     by means of a rectangular grill or by-
                                    xi

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            black lines of definite width and
            spacing on a white background •
      (b)    Equivalent Opacity is an extension of
            the Ringelmann Chart method of quantify-
            ing visible emissions.   The opacity or
            degree to which a non-black or grey
            plume obscures an observer's view is
            related to the extent to which a black
            or grey plume of a particular Ringelmann
            Number obscures an observer's view.  For
            example, a Ringelmann Number 2 plume is
            equivalent to a plume having 40% opacity.
(3)    List the following essential conditions for
      correctly evaluating the plume:
      (.a).    Keep the sun in the 140.  sector to your
            back.
      (b)_   Try to have a contrasting background-
      (c).   Readings should he taken at approximately
            right angles to the plume direction and
            at any distance to obtain a clear view
            of the emissions.
      (d).   Readings should be made through the most
            dense part of the plume and in that
            portion of the plume where condensed
            water vapor is not present.
      (e)_   When observing emissions from rectangu-
            lar outlets,  readings should be at
            approximately a right angle to the.
            longer axis of the outlet.
      (f)    The observer shall not  look continuously
            at the plume,  but  instead  shall observe
            the plume momentarily at 15-second
            intervals.
          xii

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(41   List the following essential items to be
      recorded on the training form:
      (al   Name              (d)  Wind speed
      (b)   Date              (e)_  Wind direction
      (c).   Time              (f)  Sky condition
      and properly fill out these items for his
      field recording form.
(31   List at least four of the following techni-
      ques (even though not generally in use)_ for
      measuring visible emission:

      (a)   Smoke guide       (d)_  Smokescope
      (b).   Umbrascope        (e)_  Smoke tintometer
      (c)   Photo-electric
            cell
(.61   Differentiate between the plumes emitted from
      combustion processes and industrial processes.
(.7).   Identify condensed water vapor plumes and
      breakpoint.
(.81   Make application of his knowledge of meteoro-
      logy in the following manner:
      (a).   Estimate wind speeds from 0-18 mph using
            the Beaufort Scale
      (bl   Define wind direction and estimate wind
            direction
      (c)   Estimate sky condition (percentage of
            cloud cover).
      (41   List the distinguishing characteristics
            of high and low pressure areas
      (el   Identify on a weather map the symbols
            for the following:
                 high, pressure area
                 low pressure area
         xiii

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                  cold front
                  warm front
                  occluded front
                  stationary front
       (f)    List at least two points of information
             obtained from a weather map which the
             smoke inspector could find useful in
             planning his activities.
 (9).   Testify in court as an effective expert wit-
       ness concerning visible emissions observa-
       tions.  To demonstrate his capability he
       should be able to:
       (a)    Identify 8 of the 10 criteria for being
             an expert witness
       (b)    List 5 of the 8 rules for behavior on
             the witness stand
       (cX   Cite the legal precedents set in the
             California appeal cases concerning
             visible emission regulations.
(10).   State the essential elements of his local
       or state visible emission code.
(11).   List the primary components of the emission
       generator:
       (a)_   Combustion chamber for generating black
             smoke
       (bX   Generator's exhaust manifold for white
             smoke
       (c)_   Transmissometer
       (dX   Auxiliary blower
       (e)    Recorder or indicator.
          xiv

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CHAPTER I.
VISIBLE EMISSIONS:
THEIR CAUSE AMD REGULATION
                     1.1  Visible emissions are composed of small solid or
                     liquid particles or colored gases.

                     1.2.  The more opaque a plume is from a specified source,
                     the more effluent is being emitted, all other partlc-
                     ulate and flow characteristics being equal.

                     1.3..  Some invisible pollutants such as colorless gases
                     cannot be detected by the naked eye, e.g., S02, CO.

                     1.4.  The micron (y) is a unit of length used to
                     measure particle diameters.  It is equal to 0.001 (one
                     thousandth) of a millimeter.

                     1.5.  Particles between 0.1 and 100 y are considered
                     suspended particulates in the atmosphere and are those
                     normally collected .by high volume samplers.

                     1.6.  Particles between 0.1 and 1.0 y are most capable
                     of causing haze.  They cause sunlight to scatter in the
                     visible wavelengths (0.4 to 0.7 y) of light.  Larger
                     particles are visible because they intercept or reflect
                     the sunlight.  Smaller particles have little effect on
                     the light and are invisible.
                                      1-1

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1.7.  Visible air contaminants can be classified as
          (a)  Smoke          (e)  Fumes
          (b)  Soot           (f)  Mist
          (c)  Fly ash        (g)  Certain gases
          (d)  Dust           (h)  Vapor

1^8.  Plumes of condensed water vapor are visible, but
uncombined water is generally not considered a pollutant.

1.9.  Smoke is a visible effluent"resulting from incom-
plete combustion and consisting mostly of soot, fly ash,
and other solid or liquid particles.
1.10.  Soot is a cluster of carbon particles saturated
with tar.  It is formed by the incomplete combustion of
carbon-containing material.  It is the principal cause
of the blackness of a smoke plume.

1.11.  Fly ash is unburned material arising from the
combustion of fuel.  It has sufficiently small size that
it can remain suspended in the air.  A pure fly ash
plume will be of a light-brown or cream color.

1.12.  Fumes consist of metal or metal oxide particles
less than 1 y in diameter.  These are minute solid
particles generated by the condensation of vapors from
solid matter after volatilization from the molten state.

1.13.  Dust consists of solid particles, generally
greater than 1 y in diameter, released to the air by
processes such as crushing, grinding, drilling, sweeping,
sanding, demolishing, etc.  Since they are larger than
the smoke or fume particles, they will settle to the
ground faster.
                 1-2

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1.14.  Mist consists of liquid particles or droplets
which are not composed of pure pollutant but contain it
in solution or suspension.  The droplets are of the size
of fog droplets (about 10 y — ranging from 2 to 200 y).
1.15.  Gas is fluidf such as air that has neither
independent shape or volume but tends to expand indef-
initely.  Two visible pollutant gases are nitrogen
dioxide (N0_), which is brown to yellow, and chlorine,
which is greenish yellow.
1.16.  Vapor is the gaseous phase of a substance that
at normal temperature and pressure, is a liquid or solid,
e.g., vapor from gasoline.

1.17.  Most visible plumes are composed of particulates.
The reasons for particulates being objectionable are
their effects on
          (a)  Materials      (d)  Health
          (b)  Visibility     (e)  Vegetation
          (c)  Incoming sunlight
The effects of Items (a) through (e) are discussed in
1.18 through 1.22.

1.18.  Materials.  Particulates deposited on clothes,
automobiles, or houses must be washed off.  When partic-
ulates are accompanied by sulfur dioxide and moisture,
the rate of corrosion increases.

1.19.  Visibility.  Particulates in the air reduce the
distance that one can see.  If this visual range is
decreased enough, it can cause unsafe operation of
vehicles and aircraft.
                 1-3

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1.20.  Incoming sunlight.  Particulate matter in the air
can cause the sun's rays to be reflected or scattered,
reducing the heat and light reaching the earth's surface.

1.21.  Health.  Increases in respiratory illness and
even deaths may occur from high particulate concentra-
tions, especially when sulfur dioxide concentrations are
also high.  Bronchitis patients will experience symptoms;
particles less than 5 y in diameter can reach the lungs.

1.22.  Vegetation.  Cement dust can reduce vegetation
growth and cause its damage.  Fluoride dust in the
presence of water can damage leaves.  If the fluoride
dust is deposited on plants that are.eaten by animals,
the animals can contract fluorotic poisoning.

1.23.  Regulations for restricting particulate emissions
are in common use.  The regulations are typed by
      (a)  Weight concentration, which states the limit
          in relation to amount of flue gas emitted:
          e.g., 0.20 Ib of particulates/ 1000 Ib of flue
          gas; 0.03 grains/std cu ft of flue gas at
          atmospheric  pressure and 60 F.
      (b)  Mass emission and process weight, which states
          the limit in relation to the amount of material
          processed, e.g., 12 Ib/hr of particulate for
          10,000 Ib/hr of process weight.
      (c)  Limitation on basis of thermal input in terms
          of British thermal units (Btu).  Example:  For
          coal-fired boilers of less than 10 million
          Btu/hr heat input, the emission of fly ash and
          other particulate matter shall not exceed 0.6
          pound of particulate matter/million Btu.
               1-4

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                          (d)  Boundary-line measurements of ambient air
                               quality.  Example:  The suspended particulate
                               outside the factory fence shall not exceed a
                                                                  3
                               24-hour average of 200 micrograms/m .
                          (e)  Plume shade density or opacity in terms of
                               Ringelmann Number or its extension to Equiv-
                               alent Opacity.  Example:  No emission as dark
                               or darker than that designated as No. 2 on the
                               Ringelmann Chart is allowed for a total of
                               more than 3 minutes in 1 hour.

                     1.24.  The regulation using the Ringelmann Chart and
                     Equivalent Opacity is the least time consuming and the
                     least expensive for enforcement by the air pollution
                     officer.
                     1.25.  Method 9 (40 CFR Part 60 App. A.) refers
                     to all visible emissions, black, white, or colored in
                     terms of opacity.  (See current Method 9 procedures
                     later in this manual.)

Suggested Additional Reading
                     "Effect on the Physical Properties of the Atmosphere,"
                     E. Robinson, in Air Pollution edited by A. C. Stern.
                     Vol. 1, second edition, 1968.  Vol. 2, ;third edition,
                     1976.  Academic Press, 111 Fifth Avenue, New York, NY
                     10003.
                                     1-5

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CHAPTER II.
PRINCIPLES OF
COMBUSTION
                     2.1.  Combustion or burning is the rapid oxidation of a
                     fuel.  This chemical reaction between the fuel and
                     oxygen requires a high temperature.
                     2,2.  Most common fuels contain carbon and hydrogen plus
                     sulfur and ash materials.  The ash does not burn, but
                     •ne cc-.rbon, hydrogen, and sulfur each combine with oxygen
                     .icd o roduce heat and waste gases.
                     2.3,  Two parts hydrogen plus one part oxygen equals two
                     psrts 
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compounded with the carbon to form complex tars, resins,
etc.; the sulfur is combined with other compounds or
with elements such as iron.
2.7.  Thus, to make sure in practice that all the car-
bon and hydrogen combine with oxygen, three -conditions
must be maintained in the furnace—the "three T's of
combustion":
     (a)  Sufficient time for the molecules of
          oxygen to come into contact with the
          molecules of fuel.
     (b)  An adequately high temperature to sustain
          the reaction.
     (c)  Turbulence or mixing to make sure that all
          the molecules of fuel are combined with
          the oxygen in the air.
2.-8.  One result which will occur if the "three T's"
are not sufficient is that carbon monoxide will be
formed, since insufficient oxygen will combine with
the fuel—two parts carbon plus one part oxygen equals
two parts carbon monoxide:
          2C    +    02         2CO
2.9.  Even with the "three T's," iurnaces are generally
not so efficient as to insure that every molecule of
-hydrogen and carbon will be combined with a molecule
of oxygen.  One remedy for this is to use more oxygen
than is theoretically necessary.  This extra oxygen is
supplied by using excess air.  However, there is a
penalty for using this excess air, since some of it
becomes heated and goes out the stack as part of the
flue gas.  This heat used to raise the temperature of
the excess air is wasted.
                2-2

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2.10.  Methods used to increase the effect of the
"three T's of combustion" in furnaces which are
listed below include the following:
2.11.  Temperature
       (a)  Heat the air before it enters the
            furnace.
  ~.«_  (b)  Insulate the combustion chamber of
            the furnace.
2.12.  Turbulence
       (a)  Put baffles in the combustion
            chamber.
       (b)  Introduce jets of air which stir
            up the air within the furnace as
            well as adding more air.
-^tt-a.  	:• -
2,13.  Time
       (a)  Use baffles that also cause the
            fuel and air to remain in the
            combustion chamber longer.
       (b)  Build the combustion chamber
            large enough so that the fuel
 _ ._.       and air will remain inside
13»u .-®
            long enough for the combustion
            to be completed.
                                                   i
2.14.  If some of the fuel does not receive enough^
olTTteat to burn "all the carbon, the ash will contain
some pieces of partially burned or unburned carbon.
When these particles are deposited on something, the
deposit is called soot.  When the particles remain in
       ±on in the flue gas, they form a black cloud
called smoke.
                2-3

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2.15.  If a furnace produces smoke, either the fuel
and air are not in balance or the "three T's of
combustion" are not being satisfied.  One should look
for one or more of the following conditions:
     (a)  Insufficient air for the amount of
          fuel;
     (b)  Too much air, which chills the
          flame before combustion is
          complete;
     (c)  Insufficient turbulence of the
          air through the fuel;
     (d)  Cold furnace when the fire is
          first lit or is burning at a
          low load—this is often accom-
          panied by excessive air leaking
          into the furnace through doors
          and other holes.
2.16.  All fuels or combustible materials, whether
solid, liquid, or gas, are burned as a gas.  Before it
will burn, a solid or liquid must be hea:ed until it is
transformed into the gaseous or vapor state.
Movie;  "The Three T's of Combustion"
2.17.  Several components of the kerosene lamp are
analogous to the components of other combustion units,
whether they be coal- or oil-burning furnaces, incine-
rators, internal combustion engines, or other devices.
The necessity for time, temperature, turbulence, and
oxygen is universal among all combustion devices
including the simple use of the kerosene lamp.
                2-4

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2.18.  The parts of a kerosene lamp include:
     (a)  The glass container at the base
          of the lamp where the kerosene
          is stored; this corresponds to
          a coal bunker or fuel tank.
     (b)  The wick through which the kero-
          sene is transferred from the
          storage to the burning area; this
          is similar to a coal stoker or
          a fuel line and fuel pump.
     (c)  The grate where the fuel is burned.
     (d)  The tuyere or diffuser above the
          top of the wick; the tuyere breaks
          up the fuel for better mixing with
          the air.  Its function resembles that
          of an atomizer in a fuel burner, an
          injection nozzle in a diesel engine,
          or a carburetor in a gasoline engine.
     (e)  The lamp chimney, which serves as an
          enclosed area in which the combustion
          can take place and also as an outlet
          for the exhaust gases.  The combustion
          area corresponds to the combustion
          chamber of a coal furnace or jet engine
          and to the cylinder of an automobile.
          The exhaust portion is similar to a
          smoke stack or a tail pipe.
2.19.  There are several examples given in the film
which emphasize that incomplete combustion will occur
if any one of the "three T's of combustion" is lacking.
               2-5

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2.20.  Without the tuyere to diffuse the fuel, there
is a smoky fire because the fuel cannot be intermixed
vvith e sufficient amount of air fot complete corn-
bus tier. -
2.21.  Even with the tuyere the flame remains smoky,
because the cool ambient air reduces the temperature
cf the kerosene-air mixture below the combustion
temperature.  When the chimney is placed on the lamp,
the air can enter the lamp only belcv the tuyere.  The
fuel and air above the tuyere can circulate around in
the vide part of the lamp chimney thus remaining at a
high temperature for a time sufficient for complete
combustion.
2.22.  At first, the lamp chimney glass is cold and it
cools the fuel-air mixture, causing a smoky flame.  As
the chimney xjarms up, the glass radiates heat back to
the air-fuel mixture within and maintains the combustion
temperature.  The. design of the interior cf furnaces
and the choice cf refractory material to line the walls
are directed toward reflecting the heat of combustion
on particular zones or areas within the furnace.
2.23.  If there if. too much air for the amount of fuel,
then some of the heat is used to warm the excess air
and is wasted.  The. temperature cf the gas leaving the
combustion area is reduced.
2.24.  If there is insufficient air for the amount of
fuel, the temperature oc the exhaust g^ses will "ise
but there will be a dense cloud of black smoke.  This
indicates thr.t fuel is being wasted.   A diesel engine
can be adjusted to give more power by using excess
fuel, although with the detriment cf creating a black
plume.
                2-6

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                    2.25.  The film mentions two other ways of increasing
                    the amount of air and eliminating-'smoky conditions
                                                 >
                    besides controlling the amount of air entering the lamp
                    below the flame:
                         (a)  Building a higher chimney so that the
                              air pressure from the bottom to the
                              top of the lamp chimney is increased.
                              This increased draft pulls air into
                              the combustion chamber at a greater
                              rate.
                         (t>)  Raising the bottom of the lamp
                              chimney above its bases allowing
                              air to enter above the grate.
                              This additional overfire air
                              eliminates the smoky flame, but
                              it also cools the flame causing it
                              to flutter and have a smoky tip.
Suggested Additional Reading
                 Anon, North American Combustion Handbook, 1st Ed.
                 North American Mfg. Co., Cleveland, Ohio (1952)
                 Edwards, John B., "Combustion-Formation and Emission of
                 Trace Species," Ann Arbor Science Publishers, Inc.,
                 P. 0. Box 1425, Ann Arbor, Michigan  48106 (1974)
                 "Field Surveillance and Enforcement Guide:  Combustion
                 and Incineration Sources," U.S. EPA Publication No.
                 APTD-1449, Research Triangle Park, N.C.  27711 (June 1973)
                                   2-7

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CHAPTER III.
COMBUSTION OF FUEL OIL -
CORRECT PRACTICES
Classification of Fuel Oil
                     3.1.  The crude oil that is pumped out of oil wells
                     consists of 83 to 87 percent carbon and 10 to 14 per-
                     cent hydrogen combined as hydrocarbons.  It also con-
                     tains traces of oxygen, nitrogen, and sulfur.
                     3.2.  The crude oil is refined; this consists of
                     separating and recombining the hydrocarbons of the
                     crude oil into gasoline, fuel oil, etc.  The refining
                     process includes distillation and, often, cracking.
                     3.3.  By boiling the crude oil, distillation separates
                     the hydrocarbons into groups or "fractions" which have
                     the same range of boiling points.  The fractions also
                     vary in density.
                     3.4.  The lighter fractions, such as naphtha, gasoline,
                     kerosene, and gas oil, are called the distillates.  The
                     heavier fractions include asphalt and the heavy fuel
                     oils, are called residuals.  During distillation, the
                     sulfur-bearing compounds and the ash originally present
                     in the crude oil are concentrated in the residual frac-
                     tions.
                     3.5.  Products of simple distillation are called
                     straight run.  Additional yield of gasoline can be
                     obtained by cracking the heavier fractions.
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3.6.  Cracking consists cf changing the hydrocarbon
structure of the oil.  This is done by decomposing the
oil through the application of heat and pressure with
or without a catalyst.  The resulting products then are
distilled again into heavy and light fractions.
3.7.  There are five grades of oil used as fuel oil,
labeled as Numbers 1, 2, 4, 5, and 6.  Number 6 is
often called Bunker C.  There no longer is a Number 3
oil.
3.8.  Numbers 1 and 2 are distillate fuel oils generally
used for home oil furnaces and hot-water heaters.
3.9.  Numbers 4, 5, and 6 are residual fuel oils.  Both
Number 4 and Number 5 are used in commercial establish-
ments, large apartments, and industrial plants.
Bunker C (Number 6) is used in ocean-going ships, power
generation plants, and larger commercial and industrial
burners which use over 50 gallons of oil per hour.
3.10.  Each of these oils has a set of standard specifi-
cations which distinguish it from the other oils.  These
specifications may include flash-point temperature,
water and sediment percentage, gravity,  ash,  and sulfur
content,  viscosity,  and others.
3.11.  The viscosity and the ash and sulfur contents
are the major characteristics that affect air pollutant
emissions.
3.12.  The relative ease or difficulty with which an
oil flows is its viscosity.  It is measured by the
time in seconds a standard amount of oil takes to flow
through a standard orifice at a standard temperature
(100°F or 122°F).
               3-2

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                    3.13.  Viscosity indicates how oil behaves when it is
                    pumped and shows when it must be preheated for handling.
                 ^   Numbers 5 and 6 fuel oils are high viscosity oils and
                    often require preheating facilities.
                    3.14.  The sulfur content of fuel oil may vary from a
                    trace to 5 percent while the ash may be as high as 0.3
                    percent by weight.  The distillate fuel oils are limited
                    by specification to  less than one percent sulfur and
                    Numbers A and 5 fuel oil are limited to no more than
                    0.1 percent ash.
                    3.15.  The sulfur content of the residual fuel oil
                    grades can be reduced by desulfurization processes or
                    by blending low sulfur oils with the higher sulfur oils.
                    3.16.  Crude oil contains thousands of hydrocarbon
                    compounds which are classified as paraffins, naphthene,
                    aromatics, resins, and asphalt.
                    3.17.  If an oil is high in paraffins, the temperature
                    of the flame will cause them to decompose into lighter
                    and more volatile fractions which burn easily.
                    3.18.  Aromatics do not readily decompose, but at
                    temperatures at which they do, cracking will occur which
                    can produce tar, smoke, and soot.
                    3.19.  The olefins may crack and form compounds which
                    are hard to burn.
Oil Burner Types
                    3.20.  The principal types of oil burners which have
                    been developed demonstrate a capability of coping with
                    many possible variations in oils.
                    3.21.  Oil burners do not burn oil.  They proportion
                    the air and oil and mix them in preparation for
                    burning.

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3.22.  Since all fuels burn as a vapor, the liquid oil
must either be converted to a gas in the burner
(vaporized) or divided into such small particles or
droplets (atomized) that heat within the combustion
zone of the furnace will vaporize the fuel during its
residence time in the combustion chamber of the furnace.
3.23.  If the temperature of flame in the combustion
chamber is too low, incomplete combustion and smoke
emission will result.  Cooling of the flame can occur
when the combustion chamber is too small or too much
air is introduced.
3.24.  Oil burns like an onion peels, so it is necessary
for turbulence to provide sufficient air to complete the
combustion of each successive layer.  Consequently, it
is important to mix the air and oil.
3.25.  Vaporizing burners gasify the oil by heating it
within the burner.  These burners are limited in the
range of fuels they can handle and are used only for
some residential furnaces and water heaters.
3.26.  Atomizing of fuel oil can be accoirplished in
three ways:
     (a)  Using steam or air under pressure
         .to break the oil into droplets
     (b)  Forcing oil under pressure through
          a nozzle
     (c)  Tearing the oil film into drops
          by centrifugal force.
All three methods are used in burners.
                3-4

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3.27.  With high-pressure steam - or air - atomizing
burners, the steam or air is used to break up the fuel-
oil stream at the burner tip.  The auxiliary fluid,
moving at high velocity, atomizes the slower moving oil
stream as the mixture is emitted in the furnace.  The
combustion air is introduced through registers around
each burner.  When steam is used, it prevents the
entering-oil temperature' from dropping.  This aids the
flow of high-viscosity oil and improves atomizing
characteristics.
3.28.  Oil-pressure atomizing burners depend on high
fuel pressure to cause the oil to break up into small
droplets upon passing through the orifice.
3.29.  Rotary-cup burners provide atomization by
centrifugally throwing the fuel from a rotating cup or
plate.  These burners can be divided into two classes—
horizontal rotary and vertical rotary.  The vertical
rotary is used only for domestic burners (under 10
gallons per hour).
3.30.  Horizontal rotary cup burners are used for the
residual fuel oils.  The oil is distributed on the
cup .- plate in a thin film.  The primary air from the
burner fan is discharged through an air nozzle which
has vanes to give the air a rotary motion opposite that
of the oil.  Additional air for combustion—secondary
air—must also be injected into the combustion chamber
for complete burning.
3.31.  Mechanical atomizing burners employ both high oil
pressure and centrifugal action.  The fuel oil is given
a strong whirling action before it is released into the
orifice.  These are the burners most often found at
large steam power plants.
                3-5

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3.32.  The key to optimum oil burner operation is
careful control of fuel viscosity.  A given burner
functions properly only if the viscosity at the burner
orifice is he]d between narrow limits.
3.33.  If the viscosity is too high, effective atoroi-
zation does not take place.  If the viscosity is too
low, oil flow through the orifice is too great, up-
setting the balance between combustion air and fuel.
3.34.  Most heavy residual oil must be warm to allow
pumping.  Preheaters are used to heat the oil and keep
it flowing.  For high-viscosity oils, the preheater is
likely to be located at the supply tank.  With oils of
lower viscosity, preheaters are often located at the
burner.
3.35.  Before the oil reaches the burner, it is passed
through a strainer or filter to remove the sludge.  This
filtering process prolongs pump life, reduces burner
wear, and increases combustion efficiency.
3.36.  The most important consideration in combustion
chamber design is heat release, or British thermal unit
release per cubic foot of furnace volume.  Too high a
heat release will result in excessive furnace tempera-
tures.  Too low a heat release will result in excessive
cooling of the flame and smoking fires.
3.37.  The size of the combustion chamber will determine
the heat release.  The shape of the chamber will pre-
vent the flame from impinging on the sides of the
furnace where it would cool, resulting in incomplete
combustion and smoke.
3.38.  Draft systems can be classified as natural,
induced, or forced, or combinations of these.
                3-6.-

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3.39.  Natural draft results from the difference in
pressure between the stack and the outside air.  Stacks
that are too small for the firing rate will create back
pressure.  Too large a stack will cause the same condi-
tions because of internal turbulence and too cool a
stack temperature.
3.40.  .Induced draft systems require a fan that sucks
combustion products through the boiler and forces them
up the stack-.
3.41.  .Forced-draft systems suck air in from the boiler
room, push it into the boiler, and force the combustion
products up the stack.
3.42.  The burning of oil can produce sulfur oxides,
inorganic ash, nitrogen oxides, carbon, and unburned
hydrocarbons.  The sulfur oxides and inorganic ash are
attributable to the fuel.  The air contaminants affected
by burner design and operation are carbon, carbon
monoxide, aldehydes, organic acids, and unburned hydro-
carbons .
3.43.  If a burner is operated properly, no visible
emissions should be caused by oxidizable air contami-
nants, and the concentrations of items such as alde-
hydes and carbon monoxide should be negligible.  Thus,
when an oil-burning system smokes, emits appreciable
odor, or causes eye irritation, there is something
wrong in atomization, mixing, or burning.  The burner
and fuil may not be compatible or the burner may not
be properly adjusted.
3.44.  Incomplete atomization of the oil caused by
 «
improper fuel temperature, dirty, worn, or damaged
burner tips, or improper  fuel or steam pressure may
cause the furnace to smoke.
                3-7

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                    3.45.   A poor draft or improper fuel-to-air ratio may
                    also cause smoking.
                    3.4i.   Other factors that may cause smoking are poor
                    mixing and insufficient turbulence of the air and oil
                    mixture, low furnace, temperatures, and insufficient
                    time for fuel to burn completely in the combustion
                    chamber.
                    3.47.   There are two kinds of hydrocarbon combustion—
                    hydroxylation and decomposition (cracking).
                    3.48.   Hydroxylation or blue-flame burning takes place
                    when the hydrocarbon molecules combine with oxygen and
                    produce alcohols or peroxides that split into aldehydes
                    and water.  The aldehydes burn to form C0_ and H-0.
                    3.49.   Decomposition or yellow-flame burning takes place
                    when the hydrocarbons "crack" or decompose into lighter
                    compounds.  The lighter compounds then crack into carbon
                    and hydrogen, which burn to form CO- and H_0.  A mixture
                    of yellow- and blue-flame burning is ideal.
Boilar Types
                    3.50.  The vast majority of combustion equipment is used
                    to heat or vaporize water.   These boilers and heaters
                    fall into three general classifications:  fire-tube,
                    water-tube, and sectional.
                    3.51.  In fire-tube boilers, the heated gases resulting
                    from combustion pass through heat-exchanger tubes while
                    water, steam, or other fluid is contained outside the
                    tubes.
                    3.52.  Fire-tube boilers make up the largest share of
                    small- and medium-size industrial boilers including the
                    Scotch marine and fire-box types.
                                    3-8

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                    3.53.  In all water-tube boilers, the water, steam,
                    or other fluid is circulated through tubes while the
                    hot combustion gases pass outside the tubes.  All
                    large boilers for steam generation are of this type.
                    The smallest and largest industrial units are likely
                    to be of a water-tube design.
                    3.54.  Sectional boilers use irregularly shaped heat
                    exchangers and cannot be classified as either water-
                    tube or fire-tube types.  Hot combustion gases are
                    directed through some of these passages, transferring
                    heat through metal walls to water or steam in other
                    passages.  These units are manufactured in identical
                    sections which can be joined together.  A sectional
                    boiler consists of one or more sections.
Soot Blowing
                    3.55.  Whenever fuels of measurable ash content are
                    burned, some solids such as carbon and inorganic ash
                    adhere to heat-transfer surfaces in the combustion
                    equipment.  These deposits must be removed periodically
                    to maintain adequate heat-transfer rates.  It is common
                    practic.-. to remove these deposits with jets of air or
                    steam from a long, retractable soot blower while the
                    combustion equipment is in operation.  These removed
                    soot particles are entrained in the combustion gases.
                    Thus, during these periods of soot blowing the plume
                    may have an excessive opacity.
                    3.56.  Whenever residual fuel oils or solid fuels are
                    burned in large steam generators, tube cleaning is
                    usually conducted at least once during every 24 hours
                    of operation.  At many power plant boilers, soot blowers
                    are operated automatically at 2- to 4-hour intervals.
                                    3-9.

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                    3.57.   When tubes are blowr at 2- to 4-hour intervals,
                    there is little, increase in the opacity of stack
                    emissions.  Intervals of 8 hours or more between soot
                    blowing car result ir excessive visible opacities.
Black Smcktf: and White Smoke
                    3.58.  When residual oils or solid fuels are burned in
                    a deficiency of oxygen, carbon particles and unburned
                    hydrocarbons impart a visible blackness to the exit
                    g£-se.s.
                    3.59.  Visible, emissions ranging from gray through
                    brown to white can also be created by the combustion
                    of hydrocarbon fuels, particularly liquid fuel.
                    3.60.  White or non-black smoke is the result of finely
                    divided particulates—usually liquid particles—in the
                    gas stream.  These non-black plumes generally are caused
                    by vaporization of hydrocarbons in the combustion
                    chamber.  This is sometimes accompanied by cracking and
                    the subsequent condensation of droplets.  White smoke
                    frequently is attribxited to excessive combustion air
                    or loss of flame.
                    3.61.  Visible plumes of greater than 40 percent opacity
                    are frequently observed at large oil-fired steam gene-
                    rators, where incomplete combustion is a relative rarity.
                    These opaque emissions are commonly attributed tc
                    inorganic pcrticulates and sulfuric acid aerosols formed
                    by the combination of sulfur trioxide, moisture, and
                    flue gases.  The. condensation of the sulfuric acid aero-
                    sol may be enhanced by the presence of particulate
                    .matter, which provides condensation nuclei.
                                    3-10

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Particulates
                   3.62.  Where combustion is nearly complete, inorganic
                   ash constitutes the principal particulate emission.  The
                   quantity of these inorganic solid particulates is
                   entirely dependent upon the fuel.  Distillate fuels do
                   not contain appreciable amounts of ash.  In residual
                   oils, however, inorganic ash-forming materials are
                   found in quantities up to 0.3 percent by weight, but
                   not to exceed 0.1 percent for grades 4 and 5.  However,
                   even that amount, when emitted from efficient burning+
                   is not likely to exceed air pollution control statutes.
                   3.63.  The particulates emitted from normal oil firing
                   are principally in the submicron range of diameters
                   where they can cause scattering of light.  Over 85
                   percent of the particles from efficient oil burning are
                   less than 1 micron in diameter.
                   3.64.  If incomplete combustion occurs and carbon or
                   hydrocarbon particles are emitted, then the average
                   particle size is larger.
                   3.65.  If a light fuel oil is burned in a deficiency
                   of oxygen, the resulting carbon  particles are likely
                   to be very fine.  If a residual fuel oil is in-
                   completely burned, by heating it to a temperature of
                   only 200-300 C and then cooling it, the carbon particles
                   are likely to be in the form of cenospheres.  Ceno-
                   spheres are hollow, black, coke-like spherical particles
                   of low density usually having a minimum dimension of
                   0.1 micron.
                   3.66.  Particulates emitted from residual fuel oil
                   combustion consist of 10 to 30 percent ash, 17 to 25
                   percent sulfate, and 25 to 50 percent cenosphere.
                                   3-11

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Sulfur Trioxide
                  3.67.   Of the sulfur contained in fuel oil,  about 95%
                  shows  up in the exhaust gases as sulfur dioxide,  a
                  colorless gas.   Up to 5% of the sulfur may be converted
                  to sulfur trioxide.   If the S0_ comes into contact with
                  surfaces below the dew point of the gas, the SO  com-
                  bines  with water vapor to produce sulfuric acid.   This
                  sulfuric acid mist is visible.
                  3.68.   Concentrations of S0_ are negligible  in small
                  equipment, even vhen fired with high-sulfur fuel  oils.
                  As the equipment sizes and firebox temperatures
                  increase, S0_ concentrations increase rapidly.
                  3.69.   Large steam generators may emit S0_ mist of
                  greater than 40 percent opacity when fired with oil of
                  greater than 1.0 percent sulfur.
                  3.70.   Sulfur trioxide tends to acidify particulate
                  matter discharged from combustion equipment.  This is
                  commonly evidenced by acid spots on painted and metallic
                  surfaces as well as on vegetation.  Acid damage generally
                  is the result of soot blowing.
                  3.71.   Formation of S0_ depends upon several factors.
                  Concentrations of sulfur trioxide increase with
                  increases in
                       (a)  Combustion chamber temperature;
                       (b)  Oxygen concentration;
                       (c)  Vanadium,  iron, and nickel oxide content
                            of the fuel oil.
                  3.72.   The visible plume from a large oil-fired unit
                  normally varies from white to brown, depending upon
                  weather conditions and the composition of the parti-
                  culate matter.
                                  3-12

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                    3.73.  In some cases, the SO- plume will be detached
                    from the stack.  It will become visible at the point
                    where the sulfuric acid mist is cooled below its dew
                    point.
                    3.74.  Deposits of dirt which cannot be removed by the
                    normal soot blowing of the heat-exchanger tubes act as
                    catalysts oxidizing SO- to SO-, with an increased
                    opacity of the plume resulting.  These deposits can be
                    removed by washing, but only at the infrequent inter-
                    vals when the steam generator is out of service.
Control Equipment
                    3.75.  Until recently,  the only air pollution control
                    devices that have found ready acceptance on oil-fired
                    power plant boilers were multiclones and low draft loss
                    separators used to control particulates during soot
                    blowing.  Now some oil-fired power plants have in-
                    stalled electrostatic precipitators to control the
                    particulate emissions.
                    3.76.  Use of cyclone type collectors during normal
                    operations is worthless since the collectors are not
                    efficient in removing particulates of less than 5-
                   microns  diameter, which is the range in which over 95
                    percent of the oil-fired emissions lie.
                    3.77.  The use of electrostatic precipitators for oil-
                    fired power plants is limited to areas where restrictive
                    legislation requires low particulate emissions and low
                    opacity of stack effluents.  They collect nearly all the
                    particulates including the liquid sulfuric acid drop-
                    lets.  The particulate loading may be decreased by as
                    much as 90 percent and the SO, emission may be cut in
                    half.
                                    3-13

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Suggested Additional Reading
                  Emissions From Fuel Oil Combustion,  W.  S. Smith.   DHEW,
                  PHS PubJicaticr Ho, 999-AP-2, (1962).
                  "Stationary Combustion Emissions," R. B. Engdahl, in
                  Air Pollution Vol. 3, edited by A. C. Stern.  Academic
                  Press, Inc., Ill Fifth Avenue, New York, N.Y.  10003
                  (1968).
                  Air Pollution__ Engine &jrin_E Mar.ual, 2nd Edition, edited
                  by J. J. Da'nielson, U. Si E?A AP-40, 1970, available
                  through National Technical Information Service, 5285
                  Fort Royal Road, Springfield, VA  22161.
                                  3-H

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CHAPTER IV.
COMBUSTION OF COAL
AND ITS CONTROL
Classification of Coal
                    4.1  The types of coal are
                         (a)  Anthracite (hard coal),
                         (b)  Bituminous (soft coal),
                         (c)  Lignite (brown coal).
                    4.2.  Anthracite coal is mined in Pennsylvania, Rhode
                    Island, and Arkansas.
                    4.3.  There are 23 districts in the United States which
                    mine bituminous coal.
                    4.4  Anthracite is less smoky and gives off less sulfur
                    dioxide, but it is not as abundant as bituminous.
                    4.5.  After coal is mined, it is generally prepared
                    before it is used.  Raw or unprepared coal is used in
                    some power plants—mine mouth plants.  Preparation of
                    coal includes crushing and cleaning to remove impurities,
                    drying to remove moisture, and separation into the
                    desired sizes.
                    4.6.  Two basic methods are normally used to describe
                    the composition of coal:  the Proximate Analysis and the
                    Ultimate Analysis.
                    4.7.  Proximate Analysis gives the percentages by weight
                    of the following which are found in the coal:
                         (a)  Volatile Matter - portion of the coal that
                              will form gases and vapors (hydrocarbofln,
                                    4-1

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          hydrogen, and carbon monoxide)
          and are driven off when the coal sample is
          heated in a covered crucible at 1740 F for
          7 minutes.
     (b)  Fixed Carbon - solid portion
          that is left when volatile matter
          is distilled off.  It is mostly
          carbon, burns slowly, and will
          give a bluish flame.
     (c)  Ash - portion that will not
          burn.  Slate, clay, sandstone,
          shale, carbonates, pyrite, and
          gypsum.
     (d)  Moisture Content.
The sulfur content in percent and the heat content in
British thermal units per pound (Btu/lb) are generally
also given, although they are not part of the analysis.
This Proximate Analysis may be made on the coal as
received (AR) or dry (excluding the moisture).
4.8.  The Ultimate Analysis gives.the chemical com-
position of the coal by dividing the ccal, except for
the ash, into its basic elements.
4.9.  In the Ultimate Analysis the volatile matter and
fixed carbon of the Proximate Analysis are divided into
their''chemical compohents-'-hydrogen, carbon, oxygen,
and nitrogen.            -         .
4.10.  Another measurement which describes the coal is
the Screen Analysis, or-Size Distribution.  It tell the
percentage of the coal that will fall through a screen
with a certain size opening but which will not fall
through the next smaller size screen.
              4-2

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4.11.  The Screen Analysis can be made with a screen
having either round or square holes, but the two screens
will give different totals.  Thus, the type of holes
should be specified.
4.12.  Coal sizing terms:
     Run of mine - unscreened broken coal
                   from the mine
     Slack - all the coal passing through a
             screen of a given size, such as
             3/4" slack.
     Double-screened sizes such as "egg^"
     "stove," "nut," "pea," and "stoker" -
     trade names in bituminous coal that
     are standard sizes for anthracite.
4.13.  From the air pollution viewpoint, the amounts of
volatile matter, ash, and sulfur, along with the heating
value, are the most important part of the Proximate
Analysis.  Volatile matter is related to the emission of
smoke; ash is related to particulate emission.  Sulfur
content is related to sulfur oxide emissions.  Heating
value ic related to the total amount of pollutant
production.
4.14.  The size of the coal is important to the smoke
and flue dust emission.  The optimum coal size is
determined by the method of firing.
4.15.  The impurities in coal are ash, moisture, and
sulfur.
4.16.  The ash is dispersed throughout the coal as
finely divided matter or is present as pieces of slate,
rock or clay.  The pieces of ash can be removed in
preparation plants by crushing and washing.
                4-3

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4.17.  Power plants usually burn higher ash coals, while
lower ash coals go to the retail market.
4.18.  Moisture may be present as finely divided amounts
of water dispersed throughout the coal or as water
clinging to'the coal surface.  A certain amount of
moisture is helpful in reducing the tendency of coal
tc forir. strong coke in some stokers.  It also prevents
a dust problem.
4.19.  Sulfur is fcund in coal in three forms:
  • •' (a)  As ar iron  disulfide, FeS~, called
          pyritic sulfur or as golden-colored
          iron pyrites in the form of very heavy
          balls or lenses and in small flakes or
          crystals or bands as partings.  This
          sometimes is called "Fools Gold."
     (b)  Organic sulfur originating with and
          forming an inherent part of the plant
          life that formed the coal.
     (c)  Combined sulfur, generally a sulfate
          with calcium or other mineral matter
         -and seen as a gypsum with a white
          surface or as veins in the coal.
High-sulfur coal is characterized by the fact that
content of all three forms of sulfur is high.  Very
often with high-sulfur coal, the pyritic form will be
as prevalent or more, so than the organic and sulfate
forms combined.
4.20.  The pyritic sulfur is found in small discrete
particles within the coal; a percentage of this sulfur
may be removed by washing or other mechanical means.
However, even after washing, most of the pyritic sulfur
and all of the organic sulfur will remain in the coal.
               4-4

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                   4.21.  At present, no economical means is in general use
                   for the removal of any of the organic or sulfate forms
                   of sulfur from the coal prior to its initial use.
Basics of Coal Combustion
and Combustion Equipment
                   4.22.  Some of the terminology describing characteristics
                   of most coal-burning furnace systems are as follows:
                        (a)  Fuel bed - layers of coal distributed
                             over a grate which allows the air to
                             move through the coal layers.
                        (b)  Stoker for feeding fuel - by which
                             coal can be added to the bed from
                             above (overfeed) or below (under-
                             feed) .
                        (c)  Air - which can be introduced be-
                             neath the coal burning on the fuel
                             bed (underfire air) or above it
                             (overfire air).
                        (d)  Arch - the portion of the combustion
                             chamber above the fire; it is con-
                             structed of material capable of
                             withstanding high temperatures
                             (refractory material) and is of a
                             design that will reflect the heat
                             back into the fire.
                        (e)  Heat-exchange equipment - converts
                             the heat released by the coal into
                             a form that can be used; frequently,
                             the heat exchange is accomplished by
                             placing metal tubes at the exit of the
                             combustion chamber and converting the
                             water in these tubes to steam.
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     (f)  Breeching -  originally, the connecting
          link between the furnace and the chimney;
          currently, one may expect to find one
          or more of the following between the same
          two points:  (1) economizer, (2) air
          preheater, (3) fly-ash collector (mechanical
          and/or electrical), and (4) induced draft
          fan.  In effect, the breeching thus becomes
          a series of, short duct-work connectors.
     (g)  Chimney - transports the waste products of
          combustion out into the air for disposal
          by dispersion.
4.23.  Coal will not burn as a solid; no fuel will.
The combustion process must vaporize,  gasify, or break
down a solid into individual molecules by the addition
of heat.
4.24.  When coal is burned on grates, one of two types
of feeding mechanisms is generally used—underfeed or
overfeed.
4.25.  The underfeed operation introduces the primary
air and the fuel from below the grate.  The fuel burns
from the top to the bottom of the bed.
4.26.-  Overfeed operation introduces coal to the grate
from the top and the primary air from below.  Burning
occurs from the bottom to the top of the fuel bed.
4.27.  When coal burns in an overfeed bed on a grate, the
process takes place in layers:
     (a)  At the bottom of the bed and above the
          grate where a layer of ash serves to
          protect the grate and preheat the primary
          air.
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      (b)  The "oxidation zone," where, as the air
          temperature rises, the heat vaporizes the
          volatile and carbonaceous material from
          the coal particles and removes this material.
          In this vaporous state the combustible
          material burns in the reaction:
                 C  +  02  -  C02-
          This is the hottest part of the fuel bed.
      (c)  The "reduction zone," where, because of the
          lack of oxygen, the carbon dioxide combines
          with the volatilized carbon forming carbon
          monoxide.
      (d)  The top layer,  where the volatile hydro-
          carbons and tars are driven off the fresh
          coal.
4.28.  Unless more air (secondary air) is introduced,
the hydrocarbons and tars crack, decompose, or condense
and are emitted to the atmosphere as white, yellow,
or black smoke.  If oxygen is present in sufficient
quantity at the time the volatile matter is distilled,
the hydrocarbons oxidize completely without forming
soot  "uu? smoke through the thermal cracking and con-
densation reactions.  Secondary air is sometimes called
combustion air and, since it is introduced above the
fire, it is often identical to "overfire air."
4.29.  Overfeed fuel beds are smoky because burning
gases rise through fresh fuel, thus resulting in rapid
devolatilization of the fresh fuel in a zone having a
deficiency of oxygen.
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4.?C.  Underfeed bt-ds are inherently  snicke  free.   The
£.ir anc! fres;h fuel ilov/ upward  together.  The  zone of
igniticr., which is near the point of  maximum evo3.uti.on
of the con.bustihJ e gases, is. supplied with  ample  well-
irixed air which promotes complete cctrbusticn.
4.3.1.  Heat-e>;chcp£e equipment  converts  the heat  released
by the burning of the coal into a form that can be used.
There are five categories:
     (a)  Padiant heat absorbers -  car. line
          furnace vails with wate.rc.ooied surfaces.
          The&e surfaces transmit to  the water
          the heat which is radiated  to  them.
     (b)  Boilers or convection heat  exchangers -
          the earliest boilers  were tanks containing
          water under which a fire  was built.   Next,
          the heated gases from the furnace were
          directed around the water tank and. through
          a large tube, which passed through the
          tank.  Next, this return  tube was re-
          placed by many small  tubes  (3 or  4-in.  ID).
          There are three types of  boilers  in  use
          currently:
               (1)  Fire-tube boiler  -
                    fire is itade in the  large
                    tube and the gases make
                    several passes  through  the
                    smaller tubes.
               (2)  "Fire-box"  boiler -
                    gases flow  frcir the furnace
                    through tubes,  then  reverse
                    and flow through  more tubes
                    to the stack.
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                                  (3)  Water-tube boiler -
                                       water goes from a drum
                                       through several straight
                                       tubes to another drum.
                        (c)  Superheaters or gas-to-vapor heat
                             exchangers.
                        (d)  Economizers or added-convection
                             heat exchangers.
                        (e)  Air preheaters or gas-to-gas heat
                             exchangers.
Some Terms Used in
Coal Combustion
                   4.32.  Draft is a measure of the positive pressure or
                   negative pressure (vacuum) or air or gases in various
                   parts of a combustion system.  There are several types
                   of draft:.
                        (a)  Forced draft - air pressure is supplied
                             by a fan pushing air into the system.
                        (b)  Induced draft - a negative pressure
                             is created by pulling air out of the
                             system with a fan.
                        (c)  Natural draft - suction in the system
                             is created when the flue gases expand
                             and go up the stack.  This causes pri-
                             mary air to be drawn into the furnace
                             system to balance out the negative
                             pressure.
                        (d)  Furnace draft - the pressure of the gases
                             in the furnace is positive or negative.
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          If it is positive, the gases V7ill
          leek out of the. furnace.  If it is
          negative, gases will leak in.
                                    •
     (e)  Draft losses - pressure, losses occur
          as the flue gas flows through the
          combustioi; system.
In principle, both natural and induced drafts are akin
in that they both function from the exhaust or discharge
end of the furnace system.  Forced draft functions from
the opposite or feed end of the system.
A.33.  Coke is the fixed carbon and ash which are left
after the coal has been heated.and the volatile matter
has been driver, off.  Coking coal refers to a coal that
melts and fuses to form larger lumps, even though the
coal may have been in small pieces.  Bituminous is
usually a good coking coal and anthracite is not.
4.34.  Carbon in the ash - if some of the coal is heated
enough to. drive off the volatile matter but does not
finish burning all of the carbon, the ash vill contain
some pieces of unburned carbon or coke.
4.35.  Overfire air - air is injected above the fuel
bed instead of through it as is normal.  The overfire
air is forced through jets or nozzles in the furnace
walls.  The purpose of the overfire air jets is to
increase the mixing or turbulence of the gases to insure
complete combustion and prevent smoke.
4.36.  Slagging - when molten ash particles build up on
the v;alls or tubes of 3. boiler and flow together, the
deposit is called slag and the process is celled slagging.
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Plume Visibility
                   4.37.  The visible plume from coal combustion may be
                   caused by condensed water vapor, sulfur trioxide/sulfuric
                   acid mist, organic liquids or solids, particulates,
                   and smoke.
                        (a)  Water vapor condenses and produces
                             a white plume which dissipates rapidly.
                        (b)  Sulfur trioxide and sulfuric acid mist
                             cause a detached bluish-white plume that
                             does not dissipate readily.
                        (c)  Organic liquids and solids cause a
                             white, yellow, or brown plume.
                        (d)  Particulates (including fly ash)
                             cause the plume to be white, brown,
                             or black.
                   4,,38.  Smoke - the black clouds called smoke are
                   actually small, unburned or partially burned solid
                   carbon particles and solid or liquid hydrocarbon
                   particles.  They result from the incomplete combustion
                   of the volatile products of the fuel.  The carbon of
                   the smoke does not arise from the free carbon of the
                   fuel but from the cooling of the hot hydrocarbon gases
                   of the volatile matter.  If these particles are depos-
                   ited inside the combustion system, they are called soot.
                   4.39.  Once formed, carbon soot is difficult to burn.
                   To prevent this soot from being carried away as pollution,
                   the hydrocarbons should be burned as close as possible
                   to the fuel bed before they are decomposed by the heat
                   into soot and smoke.
                   4.40.  It has been found that there is a marked rise in
                   the percentage of both carbon (soot) and tar (benzene
                   soluble) contained in the particulate as the smoke density
                   increases.
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£.41.  The black r.mckt- picirif is-, visible because of  the
size cf its solid end liquid particles.  They range
between 0.01 and 2.0 microns in diameter, bvt meat  are
between 0.3 and 0.6 ir.icrcn, a size which is highly
effective in scattering <.r absorbing light.
i.£2.  These particles between 0.3 and 0.6 ir.icrcn in
diameter contribute, little to the mass of the emissions.
i'ost cf the r.ast. is ir the larger particles, which have
little el feet in absorbing cr scattering light.
4.^.3.  The black shade of a combustion plune can be
reduced by s good adjustment of air-to-fuel ratio.
One indication of this is the flame in the furnace:
     (a)  With a good adjustment of air to the
          coal feed, the flame will be yellowish
          orange in color with nc black tips.  It
          will appear soft.  And its luminosity will
          give a maximuir of radiant heat-energy
          transfer.
     (b)  If the air is increased, the flame
          will become whiter in color and will
         • appear to be harder, sharper, and more.
          erosive.  Its radiant heat energy will
          be lessened.
     (c)  If the air is decreased toe much,
          the flame will be blacker and will
          appear lazy and without life.  Since
          a reducing atmosphere is now well
          indicated, scot may be formed and
          collect at some point in the system.
          The smoke will be. dark.
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                         (d)  When complete burning of coal
                             is accomplished, visible emissions
                             will range from zero to a light
                             tan er gray haze depending on the
                             ash content of the fuel and the
                             efficiency of the emission control
                             equipment.
                   4.44.  When a flame impinges on a cold surface, smoke
                   and soot are formed.  Complete combustion should be
                   obtained before the flame is allowed to hit a cold
                   surface.
Mechanical Coal-Firing Equipment
                   4.45.  Overfeed stokers - earliest type consisted of a
                   steeply inclined grate with alternate stationary and
                   movable sections.  Coal moved down the grate when a
                   lever outside the furnace was moved.
                   4.46.  Underfeed stokers - two forms:  single retort
                   and multiple retort.
                   4.47.  Single retort - consists of coal hopper, one feed
                   trough or retort containing a feeding device (a screw
                   or pusher) with .the grate above it.  This stoker moves
                   coal (a) from front to rear in retort, (b) from retort
                   upward to the grate where it is burned, (c) sideways on
                   the grate to the ash pits at the sides.  Widely used
                   with smaller boilers.
                   4.48.  Multiple retort - early variety had one coal
                   hopper across several parallel retorts.  Ash was dumped
                   periodically from the rear into an ash pit.  Later, all
                   the retorts were driven by a single  crankshaft.  They
                   require forced draft fans.  There may be as many as 18
                   multiple retorts.
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4.49.  Traveling grate stoker - grate surface, consists;
of an endless belt with sprockets at either end.  Coal
hopper with e grate at one. end controls the coal feed.
Grate is moved with gears powered hy an electric motor
or turbine.  Coal is laid or the grate frcm the hopper
and is moved through the furnace as the burning takes
place.  Ash is dropped off the grate into an ash pit
at the rear.  Presently forced-draft fans ?.re used with
traveling grate stokers.
4.50.  Vibrating grate stoker - consists of a water-
cooled grate structure on which the coal moves from tl-e
hopper at the front of the boiler through the burning
zone by means of a high-speed vibrating mechanism.  As
with the traveling grate, the fuel bed progresses to
the rear, where the ash is continuously discharged.
Vibrating stokers may eir.i t .slightly higher concentra-
tions of fly ash than traveling-grate stokers because
of increased agitation of the fuel bed.
4.51.  Spreader stoker - consists of a coal hopper,
a feeding mechanism, and a device that injects the coal
into the furnace (usually a rotating flipper) .  The
coal is thrown into the furnace and partly burned in
suspension.  The larger particles fall to the grate, and
burn there.  Essentially, the spreader stoker employs
overfeed burning, an inherently smokey method, plus
suspension burning, an inherently smoke-free method
producing fly ash.  Overfire jets have been found
essential to smoke-free operation.  They also reduce
dust emission significc'Titly, but not enough, to meet
most ordinances, unless a partic'ulate collector is
used.
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4.52.  Pulverized-fuel firing unit - in this system,
coal is pulverized to particles, at least 70 percent
of which pass through a 200-mesh sieve (median size of
the particles is 5.0 microns).  In direct-firing systems,
raw coal is dried and pulverized simultaneously in a
mill and is fed to the burners as required by the
furnace load.  A predetermined coal-air ratio is
maintained for any load.  In indirect-firing systems
there are storage bins and feeders between the pulver-
izers and burners.  Pulverized-fuel firing units are
of two basic types—wet bottom and dry bottom.  In a
wet-bottom unit, the temperature in the furnace is
maintained high enough so that the slag does not solidify
(or fuse) and it can be removed from the bottom as a
liquid.  The dry-bottom furnace maintains a temperature
below this point so that the ash will not fuse.  The
steam electric plants, where pulverized fuel firing is
used most, emit 50-80 percent of the ash fired in the
coal as fine fly ash.  Therefore, all modern plants of
this type must have high-efficiency dust collectors.
A.53.  Cyclone furnace - fires crushed coal that is
nearly as fine as pulverized coal into a water-cooled,
refrac .':ory-lined cylindrical chamber 8 to 10 feet in
diameter.  The coal and air swirl in a cyclonic manner
as the burning proceeds.  Combustion is so intense that
a small portion of the molten ash coating the wall of
the chamber is vaporized.  Approximately 85 percent of
the ash fired is retained as molten slag; hence, the
fly-ash load is much lower than with pulverized coal.
However, the ash which does escape the cyclone is
extremely fine and thus difficult to collect.
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                    4.54.  Prlverized-coal burners and cyclone furnaces are
                    the universal equipment for firing coal in the large new
                    electric-generating stations.
                    4.55.  Some types of burning equipment (underfeed stokers,
                    overfeed stokers, spreadt-r stokers, and pulverizec-fuel
                    burners) make use of a certain amount of fly-ash
                    ceinjection.  In this process, cinders are returned to
                    the grate from the fly-*.yh collector and burned again
                    to reduce the loss of unburned carbon.  The usefulness
                    of this nethod is limited, for whenever the fly ash is
                    re.injected pneumatically, the total fly ash from the
                    unit is eventually increased.
Causes and Control of Particulate
Emissions From Coal Combustion
                    4.56.  Emissions of smoke and particulates nay be
                    caused by the type of coal, the type of combustion
                    equipment, or improper combustion.
                    4.57.  Improper combustion - if a furnace produces
                    siaoke, either the fuel and air are not in balance or
                    the three T's of combustion are not being satisfied.
                    The cause may be. one. or more of the following conditions:
                         (a)  Insufficient air for the amount of fuel;
                         (b)  Improper distribution of the air or fuel;
                         (c)  Too much air (usually overfire air),
                              which chills the flame, before all
                              combustion is complete;
                         (d)  Insufficient turbulence or mixing of
                              the air;
                         (e)  Cold fire box - often caused by excessive
                              furnace, draft, which pulls outside air
                              into the fire box through doors and leaks;
                              it usually occurs at low load.
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4.58.  Possible causes for improper distribution of
air or fuel:
     (a)  Uneven depth of fuel bed,
     (b)  Plugged air holes in the grate,
     (c)  Clinker which shuts off air flow,
     (d)  Leaky seals around the edges of
          the grate area,
     (e)  Improper burner adjustment.
4.59.  Possible reasons for insufficient turbulence:
     (a)  Insufficient overfire air,
     (b)  Plugged overfire air nozzles,
     (c)  Nozzles that are improperly aimed,
     (d)  Incorrect burner adjustment,
     (e)  Excessive furnace draft.
4.60.  Importance of coal and equipment in particulate
emissions:
     (a)  Type of firing - least emission occurs
          with underfeed stokers, the greatest
          with pulverized coal.
     (b)  Furnace design - least emission with large
          furnaces and greatest with small furnaces
          of pulverized coal furnaces.
     (c)  Secondary air jets tend to reduce emission.
     (d)  Coal size - the greater the proportion
          of small sizes, the greater the emissions.
          Smaller sizes are more easily swept up
          the chimney.
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     (e)   Volatile content - high-volatile ccal
          results in a long, opaque flame that.
          is irore likely to strike the cooler
          surfaces of the furnace resulting in
          soot formation.  Low-volatile fuel
          burns with a short, transparent flame.
     (f)   Amount of ash - the higher the ash
          content, the greater the emission
          of fly-ash.
     (g)  . Fly-ash reinjection - if fly ash is.
          reinjected, there can be an accumulation
          in the furnace of suspended solids
          formed from the combustible portion
          of the coal.
     (h)   Firing rate - as the firing rate
          increases, the velocity of the gases
          passing through the furnace increases.
          And as the velocity increases, more
          and larger particles are carried out
          of the furnace.
4.61.  The most important variable in hand-fired furnaces
is the volatile content of the fuel burned, the smoke
potential .increasing rapidly as volatile content
increases.
4.62.  Several types of control equipment have been
used to collect the particulates from coal combustion:
     (a)   Settling chambers,
     (b)   Large-diameter cyclones,
     (c)   Multiple small-diameter cyclones,
     (d)   Wet scrubbers,
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     (e)  Electrostatic precipitators,
     (f)  Fabric Filters (ir limited use
          as of 1977).
4.63.  The settling chamber is a low-efficiency, low-
cost, low-pressure-drup device.  It generally is applied
to natural-draft, stoker-fired units.  Collection
effic.ier.cy is 50 to 60 percent.
4.64.  Large diameter cyclones have lower efficiency
and lower pressure drops than smaller diameter cyclones.
Their efficiency ranges from 65 percent for stoker-fired
units to 20 percent for cyclone furnaces.
4.65.  Multiple sirall-diair.eter cyclone, units are used as
precleaners for electrostatic precipitators or as final
cleaners.  Efficiencies range from 90 percent for
stoker-fired units to 70 percent for cyclone furnaces.
4.66.  Wet scrubbers are limited to the control of
particulate emissions during soot blowing, although
alkaline scrubbers to remove both fly ash and sulfur
dioxide are also used.
4.67.  Electrostatic precipitators are the most commonly
used devices for cleaning the gases from large, stationary
combustion sources such as those burning pulverized
coal.  They are capable of efficiencies of 99 percent
or mere.
4.68.  Efficiency of collection for cyclone collectors
increases ss the load increases.  An increase- in the
carbon content of coal is usually associated with an
increase in size distribution.  Thus, as firing rate
increases or the carbon content of the coal increases,
the centrifugal collector becomes more efficient.
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                   £.69.   The electrostatic precipitator becomes less
                   efficient as the load increases.   An increase in
                   carbon content is associated v-1tr an increase in
                   electrical resistivity.   Electrostatic precipitators
                   are net generally used for high-carbon ash, which is
                   derived from stckeis.  They are best adapted to
                   pulverized coal-fired and eyelone-fired units.
Suggested Additional. Reading
                   Atmospheric Emissions From Coal Combustion, W.  S. Smith
                   and C.  W. Cruber, DHEW,  PHS Publication No. 999-AP-24,
                   (1966).   Available through National Technical  Information
                   Service,  5285 Port Royal Road,  Springfield, VA  22161.
                   "Stationary Combustion Emissions," R.  B. Engdahl, in
                   Air Pollution Vol. J3- edited by A. C.  Stern, Academic
                   Press Inc., Ill Fifth Ave., New York,  NY  1C003,  (1968).
                   Emissions from Coal-Fired Power Plants, S.  T.  Cuffe and
                   R. W. Gerstle, DHEW,  PHS Publication No. 999-AP-35, 1967.
                   Available through National Technical Information
                   Service,  5285 Port Royal Road,  Springfield, VA  22161.
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CHAPTER V.
OTHER COMBUSTION EMISSIONS:
INCINERATORS, AGRICULTURAL BURNING,
NATURAL GAS AND MOBILE SOURCES
                     The combustion of coal and fuel oil in stationary
                     sources produces a large number of visible plumes.
                     More efficient combustion of these fuels can reduce
                     the opacity of the plumes produced from these sources.
                     Other types of combustion, both for the production of
                     usable energy and for the burning of waste materials,
                     will -produce black and non-black plumes.  Some of these
                     combustion sources and the cause and control of their
                     plumes are discussed in this section.
Solid Waste Disposal by Incineration
                     5.1  The methods of burning solid waste include the use
                     of open-top or trench incinerators, conical metal
                     ("tepee") burners, domestic incinerators, apartment-
                     house incinerators, and municipal incinerators as well
                     as open burning.
                     5.2  Incinerators can be classified in several ways,
                     such as by their size, their method of feeding, the
                     type of waste they will handle,, or the number of com-
                     bustion chambers they contain.
                     5.3  A single-chamber incinerator is designed so that
                     feeding .combustion, and exhaust to a stack take place
                     in one chamber.
                     5.4  The multiple-chamber incinerator has three or more
                     separate chambers in series for admission and combustion
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of the solid refuse, mixing and further combustion of
the fly ash and gaseous emissions, and settling and
collecting of the fly ash.
5.5.  Multiple-chamber incinerators are of two general
types:
      (a)  Retort, in which the ignition chamber,
          mixing chamber, and combustion chamber
          are arranged in a "U".
      (b)  In-line, in which the three chambers follow
          each other in a line.
5.6.  The tepee burner has been used by the lumber
industry to incinerate wood wastes and by some small
cities to dispose of municipal refuse.  These burners
range from 10 to 100 feet in height.  They are single-
chamber incinerators and are not designed to minimize
atmospheric emissions; thus, they rarely meet visible
emission regulations when in use and have considerable
fly-ash fallout.
5.7.  The tepee burner may be fed by a bulldozer, a
dump truck, or a conveyor.  Feeding with bulldozers
or trucks requires that the doors at the base of the
burner be opened.  This stops the motion of the draft
air inside the burner and cools the combustion gases.
The dumping of the charge on the burning pile smothers
the fire.  All of these factors contribute to incomplete
combustion and additional smoke.
5.8.  Domestic incinerators may range from units such
as a single-chamber backyard wire basket to dual-chamber
incinerators having a primary burner section followed
by an afterburner section.  Many air pollution control
agencies have banned backyard incinerators and some
have banned all types of domestic incinerators.
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5.9.  The emissions of smoke and fly ash from apartment-
house incincerators are often high because of low com-
bustion temperatures, improper air regulation, and poor
operating and maintenance practices.
5.10. Apartment-house incinerators may be of two types—
flue-fed and chute-fed.  In the single chamber-flue-
fed unit, refuse is charged down the same passage that
the products of combustion use to leave the unit.  Re-
fuse dropped onto the fuel bed during burning smothers
the fire, causing incomplete combustion and emission
of smoke.  Unless controlled by an approved type of after-
burner or other equivalent device, the flue-fed and
chute-fed incinerator emissions will exceed emission
standards.
5.11. A chute-fed multiple-chamber incinerator has
separate passages for refuse charging and combustion-
product emission.  Nevertheless, the emissions from
this incinerator often exceed emission standards.  One
cause is the high natural draft in the flues of the
tall stacks that go to the top of the apartment house.
This high draft carries with it a large amount of
particulates and fly ash.  A barometric damper will
alleviate the high draft.
5.12. Single-chamber incinerators used for commercial
or industrial establishments have been largely replaced
by multiple-chamber types.  They may handle from 50
to several thousand pounds of refuse per hour.
5.13. The average capacity of municipal incinerators
is 300 tons of refuse per day.  They may be fed in
batches or continuously.  Continuous-feed units are
preferable, because operating parameters—such as
combustion-chamber temperatures that affect particulate
emissions—can be closely controlled.
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5.14. The gases leaving an incinerator may have tempera-
tures as high as 1800°F, which is much higher than the
600 F, maximum for steam-generating boilers.  The
higher temperatures mean a higher plume rise but also
a greater volume of gas and more expensive breechings,
chimney linings, and air pollution control equipment.
5.15. Some rules that should be met by any incinerator
to minimize the particulate emissions are as follows:
     (a)  Air and fuel must be in proper proportion
          and mixed adequately.
     (b)  Temperature must be sufficient for combustion
          of both solid fuel and gaseous products.
     (c)  Furnace volume must be large enough to provide
          adequate time for complete burning of the com-
          bustible materials.
NOTE - these rules are a restatement of the "three T's
of combustion."
5.16. Some operating practices that can help to reduce
the smoke from incinerators include the following:
     (a)  On a cold start, feed nonsmoky material
          slowly and increase the frequency of the
          charge—not its size—until the secondary
          combustion chambers get hot.
     (b)  If smoke is a problem,  keep the charging
          opening practically blocked with waste.
     (c)  It is often an advantage to mix slow-burning
          material with flash-burning material.   This
          can be done to achieve more efficient in-
          cineration of wet garbage or it can be done
          to reduce smoke by mixing smoky materials,
          such as plastics and rubber, with paper
          waste.
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     (d)  Excessive fly ash is usually the result of too
          great a draft.  The draft can frequently be
          reduced by partially closing the damper, which
          is installed in the breeching between the
          furnace and the stack.
5.17. Dark smoke from incinerators consists primarily
of small carbon particles resulting from incomplete
combustion.  The dark smoke may mask the light-colored
plumes also emitted from the incinerator.
5.18. Light-colored plumes are emitted from most munici-
pal incinerators.  These plumes are caused by volatiliza-
tion of particles or by chemical reactions in the fuel
bed.  Analysis of the plume shows appreciable quantities
of metallic salts and oxides in microcrystalline form
which were transformed into the vapor state in the fuel
bed and then condensed.  Removal of these very small
particles from the flue gases is difficult.  The equi-
valent opacity of the plume can be partially reduced
by proper incinerator design.
5.19. Large fly-ash particles may be either charred
material or incombustible particles.  If complete
combustion is achieved, there should be no charred
particles.  The incombustible material may come from
chemical reactions in the fuel bed.  It may also be
from small particles that were present in the refuse.
5.20. The size of the particles formed by chemical
reactions may range from submicron to 10-micron diameters.
Much of the weight of the particulate matter is in the
particles greater than 5 microns.  These can be re-
moved from the combustion emissions by collecting
devices.
5.21. Several types of collection devices which have
been used with incinerators and their efficiencies

                5-5

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(by total weight of all particles without regard to
size) are given in the following tabulation: ,
                                           Collection
                                           Efficiency,
         Collection Device                   percent
Settling chamber                             10-35
Wetted baffle-spray system                   10-55
Cyclones and multiple cyclones               60-80
Wet scrubbers                                94-96
Electrostatic precipitators                  96-99+
Bag filters                                  99+
The use of bag filters for incinerators is very
limited.  Their utilization depends on considerations
of temperatures and moisture content of the gas stream
as well as the pressure drop across the filter.
5.22. The per catita quantity of solid waste generated
in the United States has been increasing in recent years.
The physical and chemical properties of the garbage have
also been changing.  Moisture content has been decreas-
ing with diminishing household garbage.  As a consequence
of the decreasing use of coal for home heating, there
are less ashes for disposal.  The combustible content
and the heat value of the solid waste have been in-
creasing, principally because of the greater use of paper
and plastics.
5.23. In a study of incineration of tepee burners,
several observations were made regarding the denisty
of smoke produced when different types of material
were burned:
     (a)  Plastic products (polyvinyl chloride, etc.),
          rubber products, and asphalt products (tar
          paper, linoleum tar blocks, etc.) produced
          Ringelmann No.  5 or 100 percent equivalent
          opacity smoke.
                 5-6

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                         (b)  Leather products produced copious quantities
                              of Ringelmann No.  5 smoke lasting hundreds
                              of yards downwind.
                         (c)  Ashes from home use produced Ringelmann No.  3
                              to 4 smoke.
                         (d)  If the refuse contained garbage of more than
                              15 to 20 percent by weight and if this garbage
                              was not mixed uniformly with dry refuse, smoke
                              emissions of No. 4  to 5 Ringelmann generally
                              occurred.
                         (e)  If the charge contained more than
                              30 percent damp material even when mixed
                              with dry combustible material, the pile
                              tended to smolder,  producing an undesirably
                              large amount of smoke.   Furthermore, the
                              buildup of a large  pile of charged refuse
                              cut down on the draft through the pile and
                              contributed to additional incomplete
                              combustion.
                    The study recommended that plastic, rubber, asphalt,
                    and leather products not be burned in tepee burners.

Agricultural Burning
                    5.24.  Open burning of several kinds is done in con-
                    nection with agriculture.  The burning is done for waste
                    disposal, for disease pest control, and as part of
                    harvesting or land management.  All of these types of
                    burning will result in visible smoke and other air
                    pollution effects such as visibility reduction, fallout
                    of carbonaceous residues, contributions to photo-
                    chemical smog, and odors.
                    5.25.  For some of this burning,  there is a flexibility
                    in the time when the burning  can be done and in the
                    area that can be burned during any one fire.  In these
                                     5-7

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                    cases, the burning should be scheduled for periods
                    when meteorological conditions such as wind speed
                    and inversion height are conductive to good dispersion
                    of the smoke.  However, the winds cannot be too strong
                    or there may be a chance of the fire getting out of
                    hand.
                    5.26.  Burning of this type includes the cleaning out
                    of weeds and brush when chemical methods are undersirable,
                    the removal of the slash remaining after logging opera-
                    tions, the clearing of potato vines, peanut vines, and
                    sugarcane leaves prior to harvest.
                    5.27.  Other agricultural burning cannot be scheduled.
                    One example is the burning of smudge pots in orchards
                    to reduce the hazard from frost.  Another is disposal
                    of cattle affected by hoof and mouth disease at a time
                    of the year when burial is not possible because of
                    frozen ground or other reasons.
                    5.28.  Other agricultural burning includes the burning
                    of field crops such as barley and rice, the removal of
                    prunings from fruit and nut trees, the incineration
                    of brush, and the burning of cotton gin waste to aid
                    in the control of bollworms.
                    5.29.  The density of the smoke from agricultural burn-
                    ing will depend upon the combustion temperature and the
                    residence time of the fuel at that temperature.  If
                    the moisture content of the fuel is high, the smoke will
                    be of a white shade indicating the presence of water
                    vapor.  The greener the plant life, the more moisture
                    it contains and the whiter the smoke will be.
Combustion of Natural Gas
                    5.30.  The particulate emissions from the normal com-
                    bustion of natural gas are insignificant compared with

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Coal
5
78
3
7
7
100
Oil
10
86
3
0.6
0.4
100
Gas
24
75
trace
1
-
100
those from coal and oil.  Control equipment is not
utilized to control the emission from natural gas
combustion equipment.
5.31.  Natural gas constituents normally includes
methane (CH,), ethane (C? H,)in varying proportions,
and lesser amounts of nitrogen (N ) and carbon dioxide
(co2).
5.32.  The table compares the chemical composition of
typical samples of coal, fuel oil, and natural gas:
                             .Content, percent
Hydrogen
Carbon
Sulfur
N,, 02, etc.
Ash
5.33.  One should note the high percentage of hydrogen
in natural gas.  This high percentage results in a
large amount of water vapor being present in the gases
exhausted from combustion.  As a consequence, the plume
from natural gas combustion under certain ambient
temperature and moisture conditions can be a very dense
white plume of condensed water vapor.
5.34.  The water produced in combustion will absorb
900 Btu's in changing from the liquid to the vapor
state.  Thus, fuels containing more hydrogen provide
less avaiJ "ible heat than fuels containing small amounts
of hydrogen.
5.35.  In heat-generating installations, one of the
principal components is the heat exchanf3r.  The heat
exchanger contains the medium, such as w^ter, that is
to be heated, and its outside surface area is exposed
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to the hot gases generated by the burning fuel.  Boilers
are rated on the total area of heating surface of their
heat exchangers.
5.36.  Burners can be divided into two broad classifica-
tions - atmospheric and mechanical draft.
5.37. The atmospheric burner depends entirely upon the
negative pressure within the furnace to draw combustion
air through the burner assembly.  Natural draft can be
created by a stack.  Theoretically, the draft is pro-
portional to the difference between the stack temperature
and ambient temperature and to the height of the stack.
5.38.  The mechanical draft burner depends upon a
blower (usually, a forced-draft blower—not an induced-
draft blower) to supply the combustion air to the
burner.  With this type of burner a low-profile building
with a short "stub" stack can be used to house the
boiler.
5.39.  Smoke from the stack of a natural gas installa-
tion is evidence of improper operation of the gas
burner, specifically, that there is insufficient com-
bustion air.
5.40.  Other indications of insufficient air will be
     (a)  A burner flame that is extremely rich,
         having an orange-red appearance;
     (b)  Soot deposits on heat-exchanger surfaces;
     (c)  Burner pulsation;
     (d)  Excessive gas consumption.
5.41.  One of the common reasons for insufficient com-
bustion air—one that is frequently overlooked—is the
lack of adequate fresh air opening into the boiler room.
There must be some permanent provision (not just an
open window) to ensure that fresh air will always be
supplied  to the combustion equipment.  One of the first
                 5-10

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                    indications of an inadequate air supply is a hot,
                    stuffy feeling in the boiler room.
Engines Used in Transportation
                    5.42.  There are three engines commonly used in the
                    United States to propel surface vehicles and aircraft.
                    These are the spark-ignited internal combustion engine,
                    the compression ignited internal combustion engine,
                    which is frequently referred to as the diesel, and the
                    aircraft gas-turbine engine.
                    5.43.  The first of these is used in automobiles, light-
                    duty trucks, light aircraft, motorcycles, outboard motors,
                    and small gasoline utility engines.
                    5.44.  The diesel engine is used in large trucks, buses,
                    locomotives, ships, and heavy construction equipment.
                    5.45.  The gas-turbine engine is commonly used on large
                    aircraft.
                    5.46.  Both types of internal combustion engines can be
                    subdivided into four-stroke-cycle engines.  These two
                    operating cycles differ in the number of times the piston
                    rises in the cylinder during the combustion of the fuel
                    in the cylinder.  Both cycles consist of four parts.
                    The operations that take place in the spark-ignition
                    engine during the four parts of the cycles are:
                         (a). Intake of air and fuel;
                         (b) Compression of fuel-air mixture during which
                             ignition of the mixture is set off by the
                             spark from a spark plug;
                         (c) Expansion of the burning mixture, forcing
                             down the piston and delivering the power which
                             drives the vehicle;
                         (d) Exhaust of the burned gases out of the cylinder.
                                    5-11

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5.47.  The differences between the gasoline and diesel
engines are the method of ignition and the fuel systems.
In the diesel engine the fuel does not enter the cylinder
as a mixture with the air but is injected into the
cylinder through nozzles during the phase when the air
is being compressed to a high pressure and high tempera-
ture.  Fuel injected into this high-temperature air
ignites without a spark.
5.48.  The aircraft gas turbine consists of four main
sections:  a compressor, a combustion chamber or com-
bustor, a turbine, and a tailpipe.
5.49.  When a plane is moving, air is forced into the
front of the engine where the compressor is.  The com-
pressor, a jnultibladed fan, compresses the air to several
times its density, increasing its temperature and pressure.
5.50.  The compressed air then passes into the combustors,
into which fuel is sprayed.  The mixture of fuel and air
is ignited producing a high-temperature exhaust gas.
5.5.1.  This exhaust gas is expanded into the turbine.
The expansion drives the turbine, giving it sufficient
power to rotate the compressor blades.
5.52.  After passing through the turbine, the exhaust
gas may still have -enough velocity to provide a back-
ward push against the outside air helping to thrust the
aircraft forward.
5.53.  There are three categories of aircraft gas-turbine
engines:'  turbojet, turboprop, and turbofan.
5.54.  The turbojet engine uses a great proportion of the
energy of the turbine exhaust gases to provide thrust
for the aircraft.  This is done by designing a suitable
exit nozzle.   Turbojet engines perform best at high
altitudes and high speeds.

                5-12

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                    5.55.  Turboprop, engines have a propeller mounted in
                    front of the compressor.  They are designed so that
                    most of the energy of the expanding exhaust gases is
                    used in turning  the turbine and subsequently to rotate
                    the propeller-.   These engines operate best at low
                    altitudes.
                    5.56.  In the turbofan engine the fans of the first
                    stages are larger in diameter than the others.  The air
                    taken into the center' portion of the compressor passes
                    through as with  the turbojet engine.  The exhaust gases
                    turn the turbine, driving the compressor, and expand out
                    the rear of the  engine producing additional jet thrust.
                    Because of the increased frontal area of this engine, it
                    is better adapted to subsonic than to supersonic flight.

Visible Emissions From
Mobile Sources
                    5.57.  Particulate matter is emitted from a gasoline
                    engine in the exhaust gases and in the blowby gases,
                    which escape past the piston rings into the crankcase
                    and then into the exhaust.
                    5.58.  Carbon, metallic ash, and hydrocarbons in
                    aerosol form are the principal particulate emissions.
                    If an automobile is performing properly these particles
                    will essentially all be less than 5 microns in size and
                    visible smoke will not occur.
                    5.59.  The color of smoky exhausts may be blue, black, or
                    white.  Blue and black smoke are indicators that the
                    engine needs repair.
                    5.60.  White smoke results from the condensation of
                    water vapor in the exhaust.  There is always water
                    vapor produced in the combustion of gasoline.  White
                    smoke from an exhaust will be more likely during cold
                                     5-13

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weather when the vapor is cooled to the visible liquid
state.  The white smoke will be more noticeable on
moist days when the air is saturated so that the wet
plume cannot evaporate and when an automobile is
standing still so the plume is not dispersed by the
motion of air.
5.61.  If the exhaust smoke has a bluish tinge, oil is
leaking into the combustion chamber of the engine and is
being burned there with the gasoline.
5.62.  Oil can enter the combustion chamber in three
ways:  through a cracked vacuum pump diaphragm, through
an excessive clearance around the intake valve, and be-
tween the piston rings and the cylinder walls.  The
latter entry may be due to worn cylinder walls or to
worn or carboned rings.
5.63.  Black-exhaust smoke is composed of unburned
gasoline.  This indicates that the fuel-to-air mixture
is excessively ric-h in fuel.
5.64.  Some causes of black smoke from a gasoline engine
are
     (a) Excessive fuel pump pressure
         or pump leakage;
     (b) Choke not opening properly;
     (c) Clogged air cleaner
     (d) Carburetor iti need of repair or adjustment;
     (e) Faulty spark plugs which cause the engine
         to "miss" and not use all the fuel.
5.65.  The California Motor Vehicle Code in essence
states that no motor vehicle first sold or registered
after January 1,  1971 shall discharge into the atmosphere
for a period of more than 10 seconds any contaminant
equal to or exceeding 20 percent opacity.   Forty percent
opacity applies to vehicles before this date.

                5-14

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5.66.  Particulate matter emitted by diesel engines
consists primarily of carbon and hydrocarbon aerosols,
which result from incomplete combustion of the fuel.
Diesel exhaust is made up of particles of which 62.5 per-
cent are less than 5 microns in diameter and 37.5 per-
cent are from 5 to 20 microns.
5.67.  Maximum emissions of visible smoke from diesel
engines occur during full-throttle acceleration and
during deceleration or "lugdown," also at full throttle.
At full or open throttle the fuel-to-air ratio is en-
riched.  This fuel-rich mixture is desirable during
acceleration because it provides greater power.  The
greater power is achieved at the expense of fuel
economy.
5.68.  The power of the diesel engine is controlled
by the amount of fuel injected into the combustion
chamber through nozzles during the compression phase of
the engine cycle.             '
5.69.  If the fuel system is kept at the setting pre-
scribed by the manufacturer, the smoke emissions should
meet established standards.  As vehicle mileage in-
creases, low levels of visible emission can be main-
tained by proper fuel system adjustment, maintenance
at appropriate intervals, use of specified type of
fuel, and good operating techniques.  Maintenance
will correct dirty or eroded injection nozzles, which
can occur even in a properly adjusted engine.
5.70.  It has been found that truck operators sometimes
increase the horsepower of their engines by altering the
fuel-injection setting prescribed by the manufacturer.
By this means the operator can install an engine which
is underrated for the load required and then meet the
power requirement by overfueling.  However, this increase

                5-15

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in power also raises the level of black smoke.
5.71.  Most turbine engines in nonmilitary aircraft
use aviation kerosene as a fuel.  The turbine engines
operate at fuel-to-air ratios five to twenty times.
less than those used by piston engines.  During flight
the emissions of particulates are low.  However during
the takeoff and landing operations, the engines
operate under high fuel-to-air ration -conditions and
visible smoke is emitted.  The quantity of the solid
material released is small, but is highly visible.
5.72.  Particulate matter originates near the upstream
end of the combustor, where fuel is injected and where
the fuel-rich regions are.  Alteration programs for re-
placing smoking engines involve the replacement of con-
ventional combustors (or burner <;ans) with new smoke-
less burner cans.
5.73.  A series of tests on different kinds of con-
ventional aircraft turbine engines has been run to
determine the density of the smoke emitted under
different power settings including idle, takeoff,
climb-out and approach power.  The results are given
in the following table.  For the JT3C-6 engine, the
dense smoke emissions at takeoff power were largely
caused by the water augmentation in this engine.
The water injection is used for additional thrust on
takeoff from a standing start to an altitude of ap-
proximately 500 fee-t.
                 5.-.16

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                    Engine Number
                    and Type
                                                Power Setting
Idle	Takeoff  Climb-out  Approach
501-D13
Turboprop
JT3D-3B
Tubofan
JT8D-1
Turbofan
< 1/2

0

3/4

< 1/2

1 1/2-2

3

< 1/2

1 1/2-2

3

< 1/2

1

3

                    CJ805-3B
                    Turbojet
                    JT3C-6
                    Turbojet with
                    water augmen-
                    tation
         3 1/2    3 1/2
Suggested Additional Reading
                    The following references may be obtained from National
                    Technical Information Services, 5285 Port Royal Road,
                    Springfield,  VA 22161.
                    Control Techniques for Carbon Monoxide,  Nitrogen
                    Oxide, and Hydrocarbon Emissions From Mobile Sources,
                    NAPCA Publication No.  AP-66, Washington, DC (1970).
                    Control Techniques for Particulate Air Pollutants,
                    NAPCA Publication No.  AP-51, Washington, DC (1969).
                    Air Pollution Engineering Manual, 2nd Edition, (1970)
                    Chapter 8.  US EPA AP-40, Office of Air  Quality
                    Planning and Standards, Research Triangle Park, NC   27711,
                    Control and Disposal of Cotton Ginning Wastes, DREW, PHS
                    Publication No.  999-AP-31, Cincinnati, Ohio, (1967).
                    Air Pollution Aspects of Tepee Burners,  T.  E.  Kreichelt,
                    DHEW, PHS Publication No. 999-AP-28, Cincinnati, Ohio
                    (1966).
                                   5-17

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Air Pollution, Vol. IV, edited by A. C. Stern, third
edition.  Academic Press, Inc. Ill Fifth Avenue,
New York, NY 10003 (1977).
                5-18

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CHAPTER VI.
NON COMBUSTION EMISSIONS AND WATER
VAPOR PLUMES
               6.1.  Discussed below are some of the equipment and the
               industries that may emit visible plumes.  Where avail-
               able, the size distribution of the particles will be
               listed.  Some of the equipment types are basic to
               several industries and processes so these types of
               equipment will be discussed first and then referred to
               in   .e -industry discussions.

Metallurgical Furnaces
               6.2.  There are several types of furnaces for melting
               metals.  They are reverberatory, cupola, electric,
               crucible, and pot.  Most of these furnaces discharge
               high-temperature effluents containing dusts and fumes
               which are less than 1 micron in size.  These effluents
               must frequently be cooled before they are ducted to a
               control device.  The control device must be capable of
               high-efficiency collection of submicron particles.
               6.3.  The reverberatory furnace usually consists of a
               shallow, generally rectangular refractory hearth for
               holding the metal to be melted.  The furnace is en-
               closed by vertical walls and covered with a low re-
               fractory-lined roof.  Combustion of the fuel occurs
               directly above the metal in the furnace.  The heat
               is radiated from the burner flame, roof, and walls onto
               the metal.  (The radiation "reverberates" within the
               furnace.)
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6.4.  The largest reverberatory furnace is the open
hearth furnace used in steel manufacture.  The charge
of metal is introduced through doors in the front wall;
finished steel and slag are poured out of a tap hole
in the rear wall.  Heat is provided by passing a
luminous flame with excess air over the charged metal.
6.5.  Other reverberatory furnaces are cylindrical and
may be fired by a flame which enters the end of the
cylinder or is directed tangentially along the side of
-the cylinder.  These furnaces are frequently used in
nonferrous (that is, excluding iron and steel) industries
for smelting small amounts of aluminum, brass, and alloys
of several metals.
6.6.  The cupola furnace is normally used in gray iron
foundries, where iron is melted and poured into a mold
or casting.  This furnace is also used to melt copper,
brass, bronze, and lead.
6.7.  A cupola is a refractory-lined cylinder open at
the top and equipped with air inlets (called tuyeres)
at the bottom.  Alternate layers of metal, coke and
limestone are dumped from a charging door in the side
of the cupola onto a burning coke bed in the bottom
of the furnace.  The combustion air for burning the
coke is forced upward through the tuyeres and layers of
charge by a blower.  The heat generated by burning
the coke melts the metal, which is drawn off through
a tap hole.  The charging and melting is a continuous
operation.  Large amounts of fine particles are
carried off in the gases.
6.8.  There are four types of electric furnaces:
direct arc, indirect arc, resistance, and induction.
               6-2

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6.9.  In the direct-arc furnace, graphite, and carbon
electrodes are placed below the slag cover of the
metal.  The current passes from one electrode through
the slag, through the metal charge, and back through
the slag to the other electrode.  The heat is generated
by radiation from the electric arc between the electrodes
and from the resistance to the passage of electricity
in the metal.
6.10..  In the indirect-arc furnace the metal charge is
placed-below the electrodes..and the .arc is formed be-
tween the electrodes and above the charge.  Indirect-
arc furnaces are used mainly in the steel industry.
6.11.  The induction furnace consists of a crucible
within a water cooled copper coil.  An Alternating
electric current in the coil around the crucible
induces eddy currents in the metal charge.  The move-
ment of these eddies develops heat within the mass of
the charge.  This furnace. is used for the production of
both ferrous and nonferrous metal and alloys.
6.12.  In the resistance furnace, the electrodes may
be buried within the metal charge or placed above it.
The charge itself acts as the electrical resistance
and generates the heat.  The resistance furnace is used
in the smelting of ores to produce ferroalloys at
temperatures up to 6000 F.
6.13.  A crucible furnace consists of a large, covered
metal p^ t lined with refractory materials such as
clay-graphite mixtures or silicon carbide.  Ther0 is
a small hole in the lid for charging the metal and ex-
hausting the products of combustion.  The crucible
of refractory material rests on a pedestal in the
center of the furnace and flames from gas or oil
burners are directed tangentially around it.  This

               6-3

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                     furnace is used for melting metals with melting points
                     below 2500°F.
                     6.14.  Pot furnaces may be cylindrical or rectangular
                     and consist of an outer shell lined with refractory
                     material,  a combustion chamber,  and a pot.   The pot
                     is made of iron or steel and in it are placed metals
                     which will melt below 1400°F.  The pot rests in the
                     furnace which supports it above the floor of the
                     combustion chamber. When melted, the metals in the
                     pot are removed by tilting the pot or by pumping or
                     dipping.

Driers
                     6.15.  A drier is a device for removing water or other
                     volatile material from a solid substance.  Air con-
                     taminants emitted include dusts and vapors.
                     6.16.  A rotary drier consists of a rotating cylinder
                     inclined to the horizontal with material fed from the
                     higher end and discharged at the lower end.  In the
                     direct rotary drier, heated air or combustion gases
                     flow through the cylinder in direct contact with the
                     material.   Air flow may be in either the same or the
                     opposite direction as the flow of material.  Dust
                     carryout increases proportionately to the square of
                     the increase in air flow through the drier.
                        In another  type, the indirect rotary drier,  heat
                     is applied by  combustion gases on the outside of the
                     cylinder or through steam tubes  inside the  cylinder.
                     €.17.   The direct rotary drier has "flights" attached
                     to the inside  of  the cylinder.   As the cylinder
                     rotates-,  the flights pick up  the material and shower
                     it down through the gas stream.   Thus,  the  direct  rotary
                     drier  has  very high potential for dust emissions.   It

                                    6-4

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                     cannot be used for drying fine material because loss
                     of product would be excessive.  Indirect rotary driers
                     are usually used for drying powdery material since they
                     have less tendency to emit dust.
                     6.18.  The flash drier consists of a furnace or source
                     of hot gases, a device for dispersing the wet material
                     through the gases, a duct through which the gases
                     convey the material, and a collection system for re-
                     moving the dried material from the gas stream.
                     6.19.  The spray drier consists of a drying chamber,
                     a source of hot gases, a device for atomizing the
                     solution particles to be dried, and a means for
                     separating the dry product from the exhaust gases.
                     Atomization is achieved either by disks which rotate
                     at a high speed, high-pressure nozzles, or by nozzles
                     that use air or by steam to break up the particles.
                     The dried product is generally separated from the
                     exhaust gases and collected in a cyclone separator.
                     6.20.  A tray or compartment drier consists of a
                     chamber containing racks on which are placed trays of
                     wet material to be dried.  Heated air circulates over
                     the wet material until the material reaches the
                     desired moisture content.
Terminology in Metallurgical
Processing
                     6.21.  The metallurgical industry can be divided into
                     primary and secondary metals industries.  The primary
                     metals industries produce the metal from ore.  The
                     secondary metals industry includes the production of
                     alloys and the recovery of the metal from scrap and
                     salvage.
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6.22.  The initial objective of metallurgical
operations is to convert the metal ore to a purer form
of the metal and then to mix it with other elements
to form an alloy.  Some of the processes used in.these
purifying operations are smelting, refining, electrolytic
reduction, sweating, and sintering.  Sometimes, two of
these terms describe the same process.
6.23.  The process of heating ores to a high temperature
in the presence of a reducing agent such as carbon
(coke) and of a fluxing agent (such as limestone) to
remove the accompanying clay and sand is termed
smelting.
6.24.  In the smelting of iron ore the ore is heated
in a blast furnace with coke and limestone at a
temperature above the melting point of iron and slag
(a mixture of the impurities and the limestone flux).
The molten iron (the more dense material) and molten
slag (the less dense material) are removed separately
from the furnace.  The limestone flux helps to purge
the metal of impurities and renders the slag more
liquid.
6.25.  Electrolytic Reduction - In this process a molten
compound containing the metal is placed in an electroly-
tic cell known as a pot,  which consists of a steel tank
lined with refractory insulating bricks.   The compound
is decomposed by a continuous direct electric current
flowing between the cathode and the anode.  The
purified metal will flow to one of these electrodes
and be deposited there.
6.26.  Roasting - This process involves heating the
material to a temperature not high enough to melt the
material but high enough to cause it to oxidize or be-
come pulverized.  The process can also be called
calcining.
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                    6.27.  Sweating Furnace - Sweating can be accomplished
                    in a furnace when the raw material is composed of two
                    metals having different melting temperatures.  The sweat-
                    ing furnace temperature is carefully controlled so that
                    the metal with the lower melting point becomes liquid
                    and flows from the furnace.  After this metal is removed,
                    the furnace burners are extinguished and the metal with
                    the higher melting point is raked from the hearth.
                    6.28.  Sintering - A mixture of ore-bearing fine parti-
                    cles and fuel such as coal or coke is burned.  The ob-
                    ject is to partially melt or sinter the material into
                    relatively coarse particles' that are more suitable for
                    other metallurgical operations than were the fine
                    particles.
                    6.29.  Quenching - The immersion of hot metals or coke
                    in liquid baths in Order to effect rapid cooling is
                    termed quenching.  The purpose of quenching ordinary
                    steel is to harden it.
                    6.30.  Materials that will resist change of shape, weight,
                    or physical properties at high temperatures are known
                    as refractories.   The materials that are chiefly used
                    for refractories are fire-clay, silica,  kaoline, diaspora,
                    alumina, and silicon carbide.   Refractories are used most
                    often in the form of bricks.
Iron and Steel Mills
                    6.31.  To make steel, iron is reduced to pig iron in a
                    blast furnace (smelting) and"most of its impurities are
                    removed as slag.   The pig iron is transformed into steel
                    in open hearth (reverberatory) furnaces, basic oxygen
                    furna'.es, or electric furnaces, where carbon, manganese,
                    silicon, and other impurities are oxidized to form gases
                    and slag.  The concentrations of the impurities are reduced
                    to the limits specified for steel.
                    6.32.  The blast furnace is the chief means for reducing
                    iron ore to pig iron.  The reduction process
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is carried out at a high temperature and in the presence
of a fluxing substance.  Furnances may be 90-100 feet
high and of varying diameters.  At the top of the furnace
is a double bell, which forms an air lock for the admis-
sion of materials during continuous operation of the
furnace.
When in use, the blast furnace is first charged with
alternate layers of coke, ore, and limestone.  The
coke is ignited at the bottom and is rapidly burned
under the influence of a forced draft of air blown
from the base upward through the furnace.  As the
coke is burned away, the material moves downward in
the furnace while the stack is kept full by fresh
charges admitted through the bells.  The iron at the
bottom is tapped off at intervals through an "iron
notch."   The lighter slag may also be tapped off
through a "cinder notch ."
As the hot gases from the combustion region pass up-
ward from the furnace they heat the fresh charges.
They then pass out of the furnace through ducts
which carry them to purifying equipment.  This gas
contains about 25 percent carbon monoxide with the
remainder being chiefly inert gases.  After the gas
is passed through dust collectors and scrubbers, it
can be burned in stoves which preheat the air going
into the blast furnace.
6.33.  "Slips" are the principal operating factor
which causes particulate pollution from blast furnaces.
A slip results from arching of the charge of coke,
limestone, or iron ore across the inside of the furnace.
When the arch finally breaks and the burden slips
downward, there is a rush of gas to the top of the
furnace, which develops abnormally high pressures
that cannot be handled by the gas-cleaning equipment.

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When this occurs, safety valves open to relieve the
pressure and to discharge a dense black or red cloud
of dust to the air.  Slips reduce efficiency and the
steel industry is constantly striving to reduce their
incidence.  Even under normal conditions most of the
particles emitted from blast furnaces are larger than 50
microns.
6.34.  The basic oxygen converter is a cylindrical
container open at one end for charging and pouring
and for oxygen injections.  In this steel-making pro-
cess, oxygen is blown at high velocity through a water-
cooled pipe downward onto the surface of the mixture
of molten pig iron, scrap iron, and scrap steel.  This
results in violent agitation and mixing of the oxygen
with the iron.  Rapid oxidation of the dissolved carbon
and silicon follows forming slag and gases.
6.35.  Sintering plants convert iron ore fines and
blast furnace flue dust into a coarser material more
suitable for charging to a blast furnace.  This is
done by applying heat to a mixture .of the iron-contain-
ing materials and coke on a slow-moving grate through
which combustion air is drawn.     , .
6.36.  Major sources of dust in sintering plants
are the combustion gases drawn through the bed and
the exhaust from the grinding, screening, and cooling
of the sinter.  Most of the particles discharged in the
sintering process are large and fall out of the air as
dustfall.
6.37.  Most of the coke used in blast furnaces is pro-
duced in "by-product" coke ovens from bituminous coal.
The by-product gases from the coke ovens are processed
in a by-product plant, where such items as tar, ammonia,
and light oils are removed.  The remaining coke-oven
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gas is used as fuel in a variety of furnaces through-
out the steel plant.
6.38.  The coke plant consists of a battery of long,
narrow firebrick ovens separated- by combustion chambers.
Coal is introduced into the red hot ovens through holes
in the top of the battery.  When the coking is finished
(17-18 hours), doors at the ends of the oven are
opened and a pusher ram shoves the entire charge of
coke into a railway car.  The hot coke will burn in the
air until the car is conveyed to a quench tower where
huge quantities of water are used to extinguish the
burning. Dust, steam, and gas emissions occur during
charging, discharging, and quenching operations.
Since the ovens in a battery are sequentially operated,
the pollutants are discharged at a fairly constant rate.
Most of the smoke and dust emitted at the coke oven
site result from the inadequacies of the charging
process, but there is also leakage of smoke and gases
because of poorly fitted or sealed oven doors.  Visible
emission regulations for by-product coke plants vary
from State to State.  At the present time there are no
Federal new source performance standard regulations,
but it is anticipated there will be by late 1978 or
early 1979.  Because of the many points and kinds of
potential visible emissions from the coke plants, it is
extremely difficult to interpret a Method 9 regulation.
Charging of coal and the pushing of coke are the main
points of concern, and inspectors should be familiar with
the coke plant operations and particularly concerned with
good mechanical maintenance by the operators.   Charging
coal into the oven is estimated to account for 60 to
70 percent of the total emissions problem of coke over
batteries.  In Allegheny County,  Pennsylvania, there
are 20% visible emissions allowed for charging and
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pushing but no visible emissions allowed for top side
leaks.  In West Virginia, for coke ovens built after
1972, visible emissions allowed are 30% for 1.5 minutes
per charge.
6.39.  Air contaminants are emitted from an open hearth
furnace throughout the process, which may last 10 hours.
Oxygen injection (.lancing) into the furnace speeds the
process but increases the amount of air pollution
emitted.  The pollutants emitted are fumes, dust, and
gases, with up to 90 percent being the red iron-oxide
fumes.  Other contaminants may arise from the grease and
oil contained in the steel scrap.  About 50 percent of
the emissions are particles less than 5 microns in
diameter.
Open hearth shops often contain several furnaces, each
having an exhaust stack.  Because of the cojt of pollu-
tion control and the growing obsolescence of open hearth
furnaces, they are being replaced by basic oxygen fur-
naces and electric furnaces.
6.40.  More emissions are created by basic oxygen fur-
naces (EOF) than by open hearth furnaces; however, all
BOF's in the United States are equipped vith electro-
static precipitators or venturi scrubbers.   The open
me nth of the EOF converter is covered by a hood, and
the emissions are conducted to the collectors.  The
particle size of the emissions is small; 85 percent are
less than 1 micron in diameter.
6.41.  In the steel industry, electric arc furnaces are
smaller than other types and are used primarily to pro-
duce special alloy steels.  Heat is furnished by direct-
arc electrodes extending through the roof of the fur-
nace.  Dust, fumes, and gases are emitted, but only 40
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Gray Iron Foundries
                     to 50 percent of the dust is iron oxide,  an amount con-
                     siderably less than that emitted by the other furnaces.
                     Approximately 70 percent by weight of the particles are
                     smaller than 5 microns.   Over 95 percent effective
                     collection can be achieved with appropriate hooding and
                     high-efficiency collection equipment.
                     6.42.  Gray iron foundries melt and cast iron.  The
                     cupola, electric, and reverberatory furnaces are used;
                     however, the cupola is the one most often employed.
                     Plant sizes range from small job cupolas operated
                     several hours a day to large units operated continuously
                     for several days.
                     Particulate emissions are composed of iron oxide,
                     dust smoke, .oil, grease, and metal fumes.  Between
                     20 and 25 percent of the dust and fume particles are
                     less than 5 microns in diameter.  The dust in the dis-
                     charge gases arises from dirt on the metal and from
                     fires in the coke and limestone charge.  Smoke and
                     oil vapor come primarily from partial combustion and
                     from distillation of oil on the greasy scrap charged
                     to the furnace.
                     The exhaust gases which carry the particulates are hot
                     and voluminous,  thus requiring a control system de-
                     signed to handle large flows.  The most effective con-
                     trol system incorporates an afterburner to eliminate
                     combustibles and a fabric filter to collect dust and
                     fume.  Coolers must be installed to cool the effluent
                     before it reaches the baghouse.
                     6.43.  Other possible sources of particulates at
                     foundries are the core ovens which bake the cores used
                     in the sand molds.   The cores contain binders that
                     require baking to develop the strength needed to
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                     resist any erosion and deformation when the molten
                     iron is poured into the mold.  Sometimes, when special
                     binders are used in the core, the ovens will emit fine
                     aerosols that can have excessive opacities and cause
                     eye irritation.  Normally, an afterburner can control
                     these pollutants.
Nonferrous Metallurgical Industry
                     6.44.  The primary and secondary recovery of copper,
                     lead, zinc, and aluminum are the chief nonferrous
                     metallurgical industries.
                     6.45.  Part of the production of aluminum involves
                     the electrolytic reduction of alumina (an oxide of
                     aluminum) in a pot that also contains cryolite and
                     fluoride salts.  The effluent released during the pot
                     reduction process contains hydrogen fluoride, fluoride
                     fumes, and fine particles of alumina and carbon.  The
                     emissions from some pot furnaces also contain hydro-
                     carbon tars.
                     6.46.  Secondary aluminum operations involve making
                     lightweight metal alloys for industrial castings.
                     Crucible furnaces, reverberatory furnaces, or sweating
                     furnaces may be used.  Fluxes help remove the dissolved
                     gases and oxide particles from the molten bath.  Chlorine
                     gas is lanced into the molten bath to reduce the
                     magnesium content.  It forms aluminum chloride fumes
                     having a small particle size.  If the scrap  charged
                     is oily or greasy, smoke is given off.  The  fluxes
                     used also produce particulate matter.
                     6.47.  The primary smelting of lead and zinc involves
                     converting  the sulfide of both ores to oxide through
                     roasting and  sintering operations.  A mixture  of  sinter,
                     iron, coke, and  limestone flux is charged  into blast

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furnaces where the burning of the coke reduces the
lead oxide to molten lead before being tapped off.
The effluent gases from the roasting, sintering, and
smelting operation contain considerable lead dust..
6.48.  Zinc oxide from the roasting of the ore or
from processing  the slag from the lead smelter can be
converted into metallic zinc by the electrolytic reduc-
tion or by distillation in retorts or furnaces.  The
distillation involves the heating of a mixture of zinc
oxide and coke until a zinc vapor is formed and the
oxygen in the zinc oxide combines with the carbon in
the coke to form carbon monoxide.  The zinc vapor passes
into a condenser where it is converted into a liquid.
During this refining process, zinc fumes and dust are
discharged.  In  spite of hoods, baghouses, and electro-
static precipitators, the white zinc oxide fume arising
from the plant is a distinctive characteristic of a
zinc retort plant.
6.49.  Scrap and salvage are the raw materials of the
secondary metals industry.  A substantial quantity of
lead is recovered from automobile batteries.  Various
types of furnaces are used.   The discharge of air
contaminants from melting furnaces is generally caused
by the excessive temperatures and by the melting of
metal contaminated with organic material.   If fuming
fluxes such as ammonium chloride are used in zinc
smelting, a fume of ammonium chloride will be observed
above the molten metal.
6.50.  Over 95 percent of the particulate emission from
the secondary smelting of zinc and lead are less than
5 microns in diameter.   Much of this is composed of
oxides of lead and zinc,  but there are also sulfides
               6-14

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                     and sulfates.  Under high temperatures, zinc vapor
                     will form the white zinc oxide fume.  Both lead and
                     zinc oxide fumes produce very opaque effluents.
                     6.51.  The recovery of copper from copper sulfide ore
                     involves roasting in multiple hearth furnaces, smelting
                     in reverberatory furnaces, and "converting" by passing
                     thin streams of air through a mixture of iron and
                     copper sulfide.  These processes emit CO,  sulfur oxides,
                     nitrogen oxides, and a fine particulate plume.  The
                     particulates consist of oxides,  dust, and  sulfuric acid
                     mist.
                     6.52.   The plumes from the primary smelting of copper,
                     lead,  and zinc contain concentrations of sulfur oxides
                     that are quite large compared with the other large
                     source-coal and oil-fired power  plants.
                     6.53.   Copper is called brass .when alloyed with zinc
                     and is termed bronze when alloyed with tin.   The re-
                     melting of nearly pure copper and bronze produces
                     only small amounts of metal fumes due to high boiling
                     temperatures and low pouring temperatures  of copper
                     and tin.  However, the secondary smelting  of brass can
                     produce zinc oxide fumes consisting of submi.cron
                     particles.
Petroleum Refineries
                     6.54.  Major sources of particulate matter at refineries
                     are catalyst regenerators, sludge burners, and the air-
                     blow ng of asphalt.  Minor emissions come from heaters,
                     boilers, and emergency flares.
                     6.55.  Modern refining processes include many operations
                     using solid-type catalysts.  These catalysts become con-
                     taminated with coke buildup during operation and must be
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regenerated by burning off the coke under controlled
combustion conditions.  The flue gases from the regen-
erator vessel may  contain hot catalyst dust, oil mists,
aerosols, carbon monoxide, and other combustion products.
If no control devices are used, a visible plume will be
emitted.  Its degree of opacity will depend upon the
atmospheric humidity.
6.56.  Two catalytic cracking processes are used:   fluid
catalytic cracking (FCC) and, less frequently, thermofor
catalytic cracking (TCC)-  The catalyst regenerator will
be different for each catalytic cracking reactor:
      (a)  The generator for the FCC units may be
          located  alongside, above, or below the
          reactor.  These regenerators normally have
          a vertical cylindrical shape with a domed top.
          External size varies from 20 feet in diameter
          by 40 feet high to 50 feet in diameter by 85
          feet high.  Internal cyclones and external
          electrostatic precipitators and carbon monox-
          ide boilers are used to control the emissions.
      (b)  TCC regenerators referred to as kilns, are
          usually  vertical structures with horizontal,
          rectangular, or square cross sections.
          Typically, one may be 10 feet square by 45
          feet high.  Wet centrifugal collectors are
          used as  dust collectors.
6.57.  Asphalt is  the residue from crude oil distillation
after all the other fractions have been boiled off.  The
residual asphalt can be refined by air blowing the
residue at elevated temperatures.   Oxygen in the air
combines with hydrogen in the oil molecules to form
water vapor.   Hydrogen is removed until the asphalt
                6-16

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                     reaches the desired consistency.  The blowing is
                     carried out in horizontal or vertical cylindrical-shell
                     stills equipped to blanket the charge with steam.  Air
                     blowing of asphalt generates oil and tar mists and malo-
                     dorous gaseous pollutants.
                     6.58.  At petroleum refineries, the incineration or open
                     burning of the heavy petroleum residues and inorganic
                     materials such as clay, sand, and acids can be a major
                     source of particulate emissions.  This sludge is atomized
                     in much the same way as heavy fuel oil.  While the
                     organic material can be burned, the inorganic matter is
                     entrained in the exhaust gases and emitted as fine dust.
                     6.59.  To prevent unsafe operating pressures in process
                     units during shutdowns and startups and to handle mis-
                     cellaneous hydrocarbon leaks or temporary high-pressure
                     conditions, a refinery must provide a means for venting
                     hydrocarbons safely.  One method is to incinerate them
                     in an elevated-type flare.  Such flares introduce the
                     possibility of smoke composed of carbon particles re-
                     sulting from incomplete combustion.  Somkeless com-
                     bustion is often promoted at elevated flares by intro-
                     ducing steam through nozzles at the top of the stack.
                     The steam jets provide turbulence and mixing with the
                     ambient air.
Portland Cement and Lime Plants
                     6.60.  Raw materials for the manufacture of portland
                     (gray) cement are ground, mixed, and blended by either
                     a wet or a dry process.  In the wet process the crushed
                     raw materials are mixed with water and ground and mixed
                     wet.  In the dry process the ingredients are used dry.
                     Raw materials consist of two basic ingredients—lime-
                     bearing material and clayey-material.

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After the raw materials are crushed and ground, they
are introduced into a rotary kiln and heated.  The kiln
is a rotating steel cylinder, lined with refractory brick,
ranging from 6 feet in diameter  by 60 feet  in
length to 25 feet  in diameter by 760 feet in length.
Heating continues  until the mixture reaches 2200. F, at
which temperature  a chemical reaction takes place rais-
ing the temperature to 2700°-2900°F.  Cement clinkers
about the size of  marbles are produced, which are cooled
and ground to a powder.  During the grinding, gypsum is
added to prevent the cement from hardening too fast
when mixed with water.
6.61.  The largest amount of particulate emission at
cement plants accompanies the exhaust gases leaving the
kilns.  Over 85 percent of the particles carried out by
these gases are smaller than 20 microns in diameter. Dust
is also generated  from the rotary driers used in pre-
paration of material for the dry process and from the
loading of cement  into bags, trucks, and railroad cars.
6.62.  Fabric filters and electrostatic precipitators
preceded by mechanical collectors are generally the
controls used.
6.63.  Gaseous contaminants from the combustion of fuel
in the kilns are usually minor.   Most of the sulfur
dioxide from the sulfur in the fuel combines with the
lime and alkalies  such as calcium oxide.
6.64  Lime is produced by calcining various types of
limestone in continuous rotary or verticle kilns lined
with refractory material.  This is accomplished by
heating the limestone in the kiln to 2000 F, driving
off the carbon dioxide, and leaving calcium oxide, which.
is called quicklime.  Two of its most important single
uses are for refractory materials and steel fluxing.

                6-18

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Kraft Pulp Mills
                     The dust generated by rotary lime kilns ranges from
                     5 to 15 percent by weight of the lime produced.  Vertical
                     kilns emit 1 percent by weight.  About 28 percent of the
                     particles are greater than 44 microns in diameter, which
                     is the size range collected in dustfall jars.  About
                     one-third are less than 20 microns in diameter.
                     6.65.  The basis of all paper products is cellulose.
                     The main source of cellulose is wood, although rags
                     can also be used.  The fibers of cellulose are bound
                     together with lignin in the pulpwood.  There are several
                     chemical pulping processes for separting the cellulose
                     from the lignin:  sulfite; sulfate or kraft; soda; and
                     alpha.  Over three-fourths of the production is done by
                     the kraft and sulfite processes.  Both emit character-
                     istic odors; however, the kraft process emits a greater
                     quantity and there are eight times as many kraft as
                     sulfite mills.  The malodorous gases include hydrogen
                     sulfide, methyl mercaptan, dimethyl sulfide, and sulfur
                     dioxide.
                     6.66.  In the kraft process, wood chips are mixed with
                     a cooking liquor of sodium sulfide, sodium hydroxide,
                     and water and cooked under steam pressure for about 3
                     hours in a large, upright vessel called a digester.
                     During the cooking period the pressure is reduced
                     periodically to prevent overburdening of the digester;
                     this is accompanied by steam emissions.
                     When the cooking is completed, the bottom of the
                     digester is suddenly opened and its contents are forced
                     into a blow tank.  The cellulose then proceeds through
                     several processes to the finished product.  The spent
                     black liquor containing the lignin is drained from the
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                     blow tank for processing to recover the chemicals for
                     reuse.  It is concentrated in multiple steam evaporators,
                     further concentrated in a direct contact evaporator,
                     burned in a recovery furnace, and dissolved in a smelt
                     tank.
                     The green liquor is pumped into a causticizer, where
                     the sodium carbonate is converted to sodium hydroxide
                     by the addition of calcium hydroxide for reuse in the
                     digester.  The calcium carbonate, also produced in the
                     causticizer, is converted into calcium oxide in a lime
                     kiln and then to calcium hydroxide, which then is reused
                     in the caueticizer.
                     6.67.  The major source of particulate emissions in
                     kraft pulping is the exhaust from the recovery furnace.
                     Sodium sulfate, which is nonodorous, is the major
                     particulate.  Sodium carbonate and carbon particles are
                     also emitted.  As the exhaust gases from the recovery
                     furnace pass to the chimney, some of their heat is used
                     to evaporate the black liquor in the direct-contact
                     evaporator.  The water vapor produced by the evapora-
                     tion can produce a sizable white plume when it con-
                     denses in the atmosphere.
                     6.68.  Other particulate emissions are lime dust from
                     the lime kiln; mists from the smelt tank, causticizer,
                     digester, and blow tank, and combustion products and
                     unburned bark from the bark-burning boiler.

Sulfuric Acid Manufacturing
                     6.69.  Basically, the production of sulfuric acid in-
                     volves the generation of sulfur dioxide (S0?), its
                     oxidation to sulfur trioxide (SO.,), and the hydration
                     of SO,, to form sulfuric acid.
                     The sulfur dioxide can be generated by burning sulfur

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or sulfur-bearing materials such as hydrogen sulfide
from oil refineries.  The highly concentrated sulfur
oxide emissions from primary smelters are also used as
input to the acid-making process although the contami-
nants such as dust must be removed from the SO,, gas if
high-quality is to be produced.
6.70.  The two main processes of producing sulfuric
acid are the chamber process and the contact process.
Over 90 percent of the sulfuric acid in the United
States is produced by the contact process.
6.71.  In the chamber process the SO- is oxidized to
S0~ by the reduction of nitrogen dioxide (NO-) to
nitrogen oxide (NO), and then it is combined with water
vapor.  This is accomplished as the hot SO- flows
through a Glover's tower, several lead chambers, and two
Gay Lussac towers.  The function of the Gay Lussac towers
is to recover the nitrogen oxides (NO and NO-)•  The
final Gay Lussac tower is the primary source of emissions
in the chamber process.  These emissions include
nitrogen oxides, sulfur dioxide, and sulfuric acid mist.
About 50 percent of the total nitrogen oxides is NO-,
which characterizes the exit gas by a reddish-brown
color.
6.72.  The contact process uses a catalyst, vanadium
pentoxide, to oxidize the S02 to SO., in a catalytic
converter.  The SO- gas is cooled in an economizer and
then passes to an absorbing tower where most of it is
absorbed in a circulating stream of  99 percent sulfuric
acid.  The SO- combines with the water in the acid to
form more sulfuric acid.  Any unabsorbed SO- passes
through to a stack to the atmosphere.  The tail-gas
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Nitric Acid Plants
                        discharge from the absorbing tower constitutes the
                        only significant air-contaminant discharge from a
                        contact sulfuric acid plant.  Most of these tail gases
                        consist of nitrogen, oxygen, and carbon dioxide, and
                        some sulfur dioxide but the S0« which is emitted will
                        hydrate and form a sulfuric acid mist upon contact with
                        the atmosphere.  Under improper operating conditions,
                        startups or emergency shutdowns, the opacity of this
                        mist can be very dense.  Minor mist emissions may come
                        from the converter, towers for drying SO,,, tank-car
                        vents, or leaks in the process equipment.
                        6.73.  The predominant factor in the visibility of an
                        acid plant's plume is the particle size of the acid
                        mist rather than the weight of the mist discharged.
                        Acid particles larger than 10 microns deposit readily
                        on duct and stack walls and contribute little to the
                        opacity of the plume.  Acid mist composed of particles
                        less than .10 microns in diameter is visible in the
                        absorber tail gases.  As the particle size decreases,
                        the plume becomes more dense because of the greater
                        light-scattering effect of the smaller particles.
                     6.74.  The ammonia oxidation process is the principal
                     method of producing commercial nitric acid.  It in-
                     volves three main steps
                        (a)  A mixture of ammonia (NH,) and air is passed
                             through a catalyst at high temperatures.  Nitric
                             oxide (NO) and water are formed.
                        (b.X  When the NO stream is cooled, the. NO reacts
                             with the oxygen remaining in the mixture to
                             form nitrogen dioxide (NO^i-
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                         (c)  The N0_ is cooled further and is passed
                             to an absorber where it is absorbed in
                             water to produce a 50 to 60 percent nitric
                             acid (HNO-).
                     If a higher strength nitric acid is required, the weak
                     acid is processed in an acid concentrator where some
                     of the water is removed by mixing the nitric acid with
                     concentrated sulfuric acid in a dehydrating column.
                     Some gases are produced in this process and they are
                     passed through an absorber tower to recover weak nitric
                     acid.
                     6.75.  The principal source of emissions in a nitric
                     acid plant is the absorber.  The tail gases from the
                     absorber contain nitric oxide, nitrogen dioxide,
                     nitrogen, oxygen, and trace amounts of acid mist.
                     Small amounts of N0« are also lost from acid concen-
                     trators and acid storage tanks.  Nitric oxide is a color-
                     less gas; nitrogen dioxide is red-orange-brown in color.
                     6.76.  Abatement of the effluents from absorption
                     towers can be effected by mixing the gases with natural
                     gas and passing them over a catalyst bed.  The nitrogen
                     dioxide and nitric oxide are dissociated and converted
                     into nitrogen,  carbon dioxide, and water vapor.  These
                     gases are then released from a stack.
Paint and Varnish Manufacturing
                     6.77.  Protective coating manufacturing may include
                     the processing of pigments, natural or synthetic resins,
                     drying oils, solvents, driers, and plasticizers.  The
                     pigments give the paint color and covering power.  The
                     resins—such as rosin—contribute to the drying speed,
                     hardness, and gloss.  The pigments are dissolved in
                     drying oils such as linseed oil, which by oxidation and
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                     polymerization (the combination of several simple
                     molecules into a complex molecule) forms a hard film
                     when applied to a surface.  Solvents or thinners, such
                     as turpentine, reduce the viscosity of the paint so that
                     it can be spread easily.  Upon application, they evapor-
                     ate from the surface.  The driers, such as cobalt soap,
                     are catalysts which accelerate the hardening of the
                     oil film.  Plasticizers may be added to keep the hardened
                     film elastic so that it will not crack when subjected to
                     vibration.
                     6.78.  Much of the manufacturing process consists of
                     cooking these ingredients at elevated temperatures to
                     cause decomposition of the products.  As long as the
                     cooking is continued, these decomposition  products are
                     emitted to the atmosphere.  A cook may average 8 to 12
                     hours.  The quantity, composition, and rate of emission
                     depend upon the ingredients in the mix, maximum tempera-
                     ture, rate of heating, stirring, method of introducing
                     additives, and the extent of air or inert  gas blowing.
                     6.79.  Emissions include organics, odors, vapors, fumes,
                     gases, and particulate matter ranging from 2 to 20
                     microns in dimension.  Scrubbers have little effect on
                     most of these small particles.
Hot-Mix Asphalt Batching Plants
                     6.80.  All hot-mix asphalt plants incorporate the
                     following processes:  conveying proportioned quantities
                     of cold aggregate (stone, gravel, and sand) to a dryer,
                     heating and drying aggregate in a rotary drier, screen-
                     ing and classifying the hot aggregate in bins, weighing
                     out the desired quantities of aggregate sizes, heating
                     the asphalt oil, mixing the hot aggregate and hot
                     asphalt in the proper proportions, and delivering the
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hot mixture into trucks which haul it to the paving
site.  Strictly speaking, this mixture of aggregates
and asphalt cement should be called asphalt concrete
or bituminous concrete, but it is frequently referred to
as just "asphalt".
6.81.  Dust originating in the aggregate is the major
atmospheric pollutant from asphalt plants, and the
principal source of this dust is the rotary drier.
The dust is carried out through the upper end of the
drier with the exhaust gases.  Other important sources
of dust are the vibratory screens, unenclosed bucket
elevators, weigh hopper, storage piles and bins, and
traffic dust from the yard.
6.82.  Most driers employ a single dry cyclone as a
precleaner, which collects 70 to 90 percent of the
exhaust dust.   This precleaner catch is discharged
back into the bucket elevator where it rejoins the
heated aggregate and continues in the process.  Of
the particulate emissions from the precleaner, 25
percent are between 5 and 10 microns and 35 percent
are less than 5 microns in diameter.
6.83.  Elevators, hot bins, and screens are enclosed
and normally vented to the inlet of the secondary
collector.  The stream of dust laden gases is combined
with that of the primary collector (cyclone or multi-
clone) serving the rotary dryer and this enters into
the secondary collector.  By the use of high energy
scrubbers (approximately 30 inch H90 pressure drop)
or fabric filters, high removal efficiencies are
possible; however, a visible water vapor plume will be
emitted as part of the exhaust from the wet scrubber.
Since regulations have become more strigent, fabric
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                     filters are now in general use.  Economics often
                     favor the fabric filter over the venturi scrubber
                     when meeting NSPS.
Phosphoric Acid Manufacture
                     6.84.  Two processes are used to manufacture phosphoric
                     acid.  High-purity acid for use in the food, detergent,
                     and plastic industries is produced by the thermal pro-
                     cess, also.called the phosphorus-burning process.  The
                     wet process is used to manufacture less pure phosphoric
                     acid for the phosphate fertilizer industry.
                     6.85.  Phosphate rock contains a compound consisting
                     of calcium, phosphorus, oxygen, and fluorine.  This
                     compound can be reduced (driving off the oxygen), in an
                     electric furnace so that pure phosphorus is produced.
                     Pure phosphorus ignites immediately when exposed to
                     air; therefore, it is generally submerged under water.
                     For use as a raw material in the thermal-process phos-
                     phoric acid manufacture, the phosphorus is usually con-
                     verted to a liquid, placed under water, and shipped
                     in a tank car.
                     6.86.  Thermal-process phosphoric acid manufacture in-
                     volves three steps:
                        (.a)  Oxidizing (burning) the liquid phosphorus
                             by mixing it with air in a combustion chamber
                             to produce the compound phosphorus pentoxide
                             (P205) vapor.
                        (b).  Passing the vapor into a hydrator where
                             it is mixed with water or weak phosphoric
                             acid to produce a higher strength phosphoric
                             acid mist.
                        (.c)  Removing the mist from the gas stream in
                             an absorber.  The strong phosphoric acid is then
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        stored for shipment or is treated further
        if it is to be used in the food industry.
6.87.  The principal atmospheric emission from the
thermal process is the acid mist emitted from the
absorber that fails to be collected by the electro-
static precipitator or mesh-entrainment separators.
The mist particles are generally less than 5 microns
in diameter.
6.88.  This mist is extremely hygroscopic so that,
unless there is a high collection efficiency, a
dense white plume of 100 percent opacity is emitted
from the stack.  The plume may range from 40 to 50. per-
cent water vapor.  Depending on weather conditions and
acid mist concentration, the plume usually dissipates
in a few hundred feet.
6.89.  In the wet process of phosphoric acid manufacture,
finely ground phosphate rock is decomposed by sulfuric
acid in a reactor (pr digester), tank for a period of
several hours.  During this process weak phosphoric
acid and gypsum crystals are created.
6.90.  The slurry of these two compounds is sent to a
filter system (e.g., a tilting pan vacuum filter).,
where the gypsum cake is washed out leaving 32 percent
acid.
6.91.  This acid is then concentrated to 54 percent in
an evaporator or concentrator.
6.92.  Phosphate rock may contain as much as 4 per-
cent fluorine.  Emissions from wet-process phosphoric
acid manufacture consist of rock dust, fluoride gases
(primarily silicon tetrafluoride), fluoride particulates,
and phosphoric acid mist.
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                     6.93.  Most of the particulate emissions come from the
                     reactor and some from the filter.  These participates
                     are often removed by wet collectors.
                     6.94.  The reactor, the evaporator, and the filter
                     are all sources of fluoride emissions.
                     6.95.  Most of the phosphate rock mined in the United
                     States is mined in Florida.  This is where most of the
                     wet-process phosphoric acid plants are and where much
                     of the phosphate fertilizer manufacture is carried on.
Phosphate Fertilizer Manufacture
                     6.96.  Three different manufacutring processes produce
                     three phosphate fertilizers, each having a different
                     grade of phosphorus pentoxide (P^O,-), nutrient.  These
                     are normal superphosphate (18 percent), a triple super-
                     phosphate (45 percent or 54 percent)., and diammonium
                     phosphate (64 percent).
                     6.97.  In each of these processes there are emissions
                     of particulates,  silicon tetrafluoride and hydrogen
                     fluoride.  The particulate dusts are visible; the
                     fluorides can cause damage to livestock through
                     fluorosis.
                     6.98.  Many of the particulate emissions come during the
                     drying of the fertilizer and during the handling of it
                     on conveyor belts or in curing and storing sheds.
                     6.99.  Dust is also produced in plants that granulate
                     the fertilizer or blend it.   In graulation, the particle
                     size of the fertilizer is increased to aid in the handl-
                     ing and storage of the fertilizer.
                     6.100.   Normal superphosphate fertilizer is being
                     replaced by high-analysis fertilizers.  It is produced
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                     by mixing dry-ground phosphate rock with sulfuric acid.
                     The mixture is poured into a large enclosed container or
                     "den", where it solidifies.  The solid is then shaved off
                     by cutters and stored for drying.  The major portion of
                     the emissions comes from the storage building.
                     6.101.  Triple superphosphate is produced by a contin-
                     uous process in which dried and ground phosphate rock is
                     mixed with phosphoric acid.  The product can be treated
                     in several ways:
                        (.a)  It can be discharged to a slowmoving belt
                             where it becomes solidified.  Then it will
                             be stored in a curing building.  After 30-60
                             days it is dug out from the "pile" in the
                             curing shed and crushed, screened, and shipped.
                        (b)  It can be fed as a slurry to a "blunger"
                             where it is mixed by rotating blades and
                             granulation is begun.  The granulation is
                             completed in heated dryer kilns.
                        (c).  The cured and screened triple superphosphate
                             produced in (a) can also be passed through a
                             drum granulator in the presence of steam and
                             then dried in a horizontal rotary kiln.
                     6.102.  The usual methods of control in the phosphate
                     fertilizer industry are scrubbers, inertial separators,
                     and fabric filters.
Soap and Synthetic Detergent Manufacture
                     6.103.  The production of soap normally involves the
                     hydrolysis or "splitting" of fats to obtain fatty acids,
                     followed by boiling the fatty acids with-sodium or
                     potassium hydroxide in large kettles for several days.
                     6.104.  After cooking, the soap is dried to remove the
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                     moisture and can be finished in several different forms-
                     bars, flakes, chips, or powder.  The hot-air process is
                     used to dry the soap for bars, flakes, and chips.  Soap
                     powder is finished by spraydrying—the blowing of hot
                     air upward in tall towers while soap drops are falling
                     downward.
                     6.105.  Synthetic detergents are produced by combining
                     a fatty alcohol or linear alkylate with sulfuric acid
                     and then neutralizing it with caustic.  The product is a
                     paste mixed with water.  The paste is pumped to a
                     large Cpossibly 100 feet high by 20 feet in diameter)
                     spray .tower where it is dried to the desired moisture
                     content.
                    ,6.106.  The principal sources of particulate matter in
                     the making of soap and synthetic detergents are the
                     spray drying of products and the handling of dry raw
                     materials.  Fabric filters are widely used to control
                     dusts from handling.
                     6.107.  The hot exhaust from the tower contains fine
                     particles together with moisture evaporated from the
                     soap or detergent during the spray drying.  Often, the
                     exhaust is passed through both a cyclone and a wet
                     scrubber before it is released.
                     6.108.  The exhaust is close to the staturation tem-
                     perature, particularly if a wet scrubber is used, and
                     it will form a dense white plume that is principally
                     condensed water vapor.

Wet Plumes
                     S.109.  Most air contains some amount of water in the
                     vapor or gaseous phase.  Water in this vapor phase is
                     invisible.  Only when it is changed to the liquid or
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solid phase does the water become visible as clouds,
fog, rain, snow, etc.
6.110.  Relative humidity is one measure of the amount
of water vapor in the air.  The warmer the air is, the
more water vapor it can hold without the vapor condens-
ing into the liquid state.  Thus, the relative humidity
of air can be increased in two ways:
   (.a)  Adding more moisture,
   Cb)  Cooling the air.
6.111.  If either of these methods for increasing
relative humidity is carried on long enough, the air
becomes saturated.  Any more water vapor added or any
further cooling results in the excess water vapor
changing phase and becoming visible.
6.112.  If hot, moist effluent is released to a
cooler atmosphere, the moisture will condense to form
an opaque white plume; if the relative humidity of the
atmosphere is high, this plume will persist for some
distance downwind from its emission point.
6.113.  The visible water plumes may be objectionable
if they
   Ca)  Contribute to the formation of ground
        fogs that obscure visibility for automobiles
        or airplanes;
   (b)  Contribute to icing conditions when they
        come in contact with very cold surfaces;
   (.c)  Combine with some other gas (such as sulfur
        trioxide) to form a harmful pollutant (such
        as sulfuric acid);
   (d)  Are aesthetically displeasing to the neighbors.
6.114.  A pure water plume disappears without a trace.
It evaporates and mixes in all directions in a wispy
pattern.

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6.115.  Plumes containing both water and dust will
leave a trail of particulates after the liquid water
evaporates.  One method of "reading" these plumes to
observe infractions of equivalent opacity regulations
is to watch them at the point where the water vapor has
evaporated.
6.116.  Other regulations specify that only plumes
containing "uncombined water" may be neglected in
enforcing equivalent opacity regulations.  This means
that if the water plume contains particulates it should
be kept under surveillance for violation of visible
emissions standards.
6.117.  Water plumes can be distinguished from plumes
of white particles in several ways:
   (a)  The wispiness of the plume as it evaporates;
   (b)  The greater frequency of occurence and a
        greater length of plume in cold, wet weather
        than in warm, dry weather;
   (c)  The detachment of the visible plume from the
        top of the stack in hot; dry weather, when
        it takes the plume longer to cool to its
       •saturation point.
6.118.  Water vapor can be emitted from
   (a) .Drying operations that remove water by evapora-
        tion from foods, chemicals, detergents, paper,
        Pharmaceuticals, ores, etc.
   (b)  Combustion in .which hydrogen-containing fuels
        are used.   This is especially true of
        natural gas combustion and the burning of wet
        fuel.
   (c)  Air pollution control devices that use water
        to remove the gases or particulates from the
                6-32

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                             gas stream (for example, spray chambers, spray
                             towers, and venturi scrubbers).
                        (d)  Evaporation of water to remove combustion or
                             chamical reaction heat from a process (for
                             example, forced and natural draft cooling
                             towers, operations for cooling hot gases
                             to protect pollution control equipment,
                             removal of the heat generated in the thermal
                             process of producing phosphoric acid).
                     6.119.  If visible wet plumes must be eliminated, several
                     methods are available:
                        (a)  Dilution of the plume by mixing it with hot
                             air;
                        (b)  Superheating the plume prior to emission  so
                             that it will disperse before it condenses;
                        (c)  Condensing the water out of the plume by
                             cooling it prior to emission.
                     These are all expensive, however.
Suggested Additional Reading
                     The Chemical Process Industries,  R.  N.  Shreve, Third
                     Edition, McGraw-Hill, New York, (1967).
                     Control Techniques for Particulate Air  Pollutants,
                     NAPCA Publication No. AP-51,  Washington,  D.  C., (1969).
                     National Technical Information Service,  5285 Port
                     Royal Road,  Springfield,  VA 22161.
                     Compilation of Air Pollution Emission Factors.  Second
                     edition AP-42, (April 1973)_r U.S. Environmental
                     Protection Agency, Office of Air  Quality Planning and
                     Standards, Research Triangle Park, NC 27711.
                                      6-33

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        Note:  Above has been supplemented by six
               supplements from July 1973 to April
               1976.
Air Pollution Engineering Manual, edited by J. J.
Danielson, Publication No. AP-40, USEPA, 2nd edition,
(1973).  National Technical Information Service,
5285 Port Royal Road, Springfield, VA 22151.
Background information documents for New Source
Performance Standards are available for those sources
shown in Section XVI of this manual.  Where visible
emissions are discussed, rationale is given for the
selection of the opacity limitation.
        Source:  Standards Development Branch
                 (MD-13), Emission Standards
                 and Engineering Division, US
                 Environmental Protection Agency,
                 Research Triangle Park, NC 27711.
Field Surveillance and Enforcement Guide for
Primary Metallurgical Industries, US Environmental
Protection Agency, EPA-450/3-73-002, Research
Triangle Park, NC, (December 1973)..  National Technical
Information Service, 5285 Port Royal Road, Springfield,
VA 22151.
US Environmental Protection Agency's Div. of
Stationary Source Enforcement, Washington, D.C.
issues inspection manuals and guidelines on various
industrial categories and a limited amount of these
are available at no cost from the EPA Library,
Research Triangle Park, NC, or at a nominal fee from
the National Technical Information Service, 5285 Port
Royal Road, Springfield, VA 22151  Non-combustion
documents are as follows:  Emissions from Hot-dip
                6-34

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Galvanizing Processes, EPA No. 905/4-76-002 NTIS No.
251910 Asphalt Concrete, EPA No. 340/1-76-003 NTIS
No. 245848/AS
                6-35

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CHAPTER VII.
CLASSIFICATION AND IDENTIFICATION
OF SOURCES
Classification
                     7.1.  One reason for classifying sources is to aid one
                     in discussing their emissions of pollutants.  Measure-
                     ments have been made of the quantity and types of
                     pollutants emitted for a given amount of fuel or raw
                     material used in a process.  Using these "emission
                     factors, [  the amount of pollutants emitted from power
                     plants, industry, automobiles, etc., can be estimated.
                     The arranging of sources into categories also makes it
                     easier to point out the similarities in plant appearance,
                     process equipment, and collection devices.
                     7.2.  There are several categories into which one can
                     divide or subdivide air pollution sources:
                        (a)  Mobile and stationary sources;
                        (b)  Point and area sources;
                        (c)  Combustion and noncombustion sources;
                        (d)  Industrial, steam-electric, residential,
                             and commerical-industrial sources;
                        (e)  Sources burning coal, oil, gas, or wood
                             versus sources not burning fuel such as
                             forest fires, agricultural fires, or
                             solid waste disposal;
                        (f)  Reciprocal engines and continuous
                             combustion engines.
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7.3.  Point Sources are ones whose emissions exceed
some designated value (for example, 50 tons/year).
Sources with smaller emissions can be grouped  together
in some manner (for example, all the residences in a
certain square mile of a city) to constitute an Area
Source.
7.4.  An example of a classification system that  includes
all sources is
   (a).  Fuel Combustion in Stationary Sources
        (1).  Industry
        (2)  Steam-Electric Power Plants
        (3)  Residential
        (4).  Commercial-Institutional
   (bl  Fuel Combustion in Mobile Sources
        (1)_  Motor Vehicles
        (2)  Vessels
        (3)  Railroads
        (4).  Aircraft
   (c).  Industrial Process Losses
        (1).  Chemical Processing
        C2).  Food and Agriculture
        (31  Metallurgical
        (.4),  Mineral Products
        (.5),  Petroleum Refining
        (6)  Pulp and Paper
        (7)  Solvent Evaporation and Gasoline Marketing
        (8)  Other
   (d).  Solid Waste Disposal
        (1)  Municipal Incineration
        (2)  On-Site Incineration
        (31  Open Burning
               7-2

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Identification
                        (e)  Miscellaneous
                             (1)  Forest Fires
                             (2)  Structural Building Fires
                             (3)  Coal Refuse Burning
                             (4)  Agricultural
                             (5)  Other
                     7.5.   These categories can be subdivided further, such
                     as into point and area sources; diesel-and gasoline-
                     powered vehicles; jet and piston-powered aircraft; and
                     particular types of industries.
                     7.6.   Without experience an inspector must use various
                     methods and clues to determine the origin of the
                     visible plumes he sees.
                     7.7.   To learn the nature of the process, he may use
                     books from the library or other sources describing
                     manufacturing.  Also descriptive of the processes and
                     the air pollution arising from them are Federal
                     Government publications.
                     7.8   The inspector can learn about the processes and
                     their emissions by asking questions of his associates
                     and of plant operators,  by observing process operations,
                     and by taking photographs of manufacturing operations
                     and noting the similarities between types of operations.
                     7.9.   Clues to the origin of emissions can be obtained
                     from
                        (a)  The Company's name;
                        (b)  Directory of Manufacturers - often published
                             by Chamber of Commerce of the city or by
                             the state;
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(c)  Air Pollution files of permits for construction
     or for operation;
(d)  Surroundings of the source such as objects
     sitting in the yard.  These might include
     the fuel used, the raw materials, the products,
     the waste material, and the trucks for carrying
     out the product;
(e)  The shape of the building housing the
     process;
(f)  Whether the source of emissions is a stack
     or whether the emissions consist of dust
     coming out of the building—called fugitive
     dust;
(g)  Color of the plume;
(h)  Odor;
(i)  Effects on metal structures, paint,
     vegetation, etc.;
(j)  Any collection devices for particles
     such as scrubbers, cyclones, electric
     precipitators, baghouses, ponds, etc.;
(k)  Flares for burning waste gases;
(1)  Any equipment that is visible such as furnaces,
     towers, rotary driers;
(m)  Any variation of the plume during the day
     or during the year which might indicate
     startup operations, batch operations,  or
     changes in operation with weather;  is  it a
     continuous process for 24 hours a day  or does
     it cease at the end of the work day?
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7.10.  Many visible plumes are wholly or partially
condensed water vapor plumes.  An inspector should be
able to identify these since they generally are not
considered as violations of visible emission regulations,
Some sources of water vapor plumes include:
   (a)  Drying operations;
   (b)  Combustion operations in which the waste gases
        are discharged at temperatures near the dew-
        point;
   (c)  Air pollution control equipment that cleans
        the plume by spraying it with water;
   (d)  Operations in which heat is removed by the
        evaporation of water.
7.11.  The inspector should be able to identify the
nature of the particulate, whether it is dust, fume,
smoke, mist, vapor, or gas.
7.12.  If he knows what type of manufacture is going on,
then he should be able to identify the possible com-
ponent manufacturing processes and their equipment.
7.13.  The inspector should determine whether the
emissions are in the form of a
   (a)  A plume;
   (b)  A cloud that has become completely
        divorced from its source;
   (c)  A haze that exists over a portion but
        not all of a community indicating that
        a local problem is present;
   (d)  "Fugitive" emissions, which do not come
        out of a stack but from windows and other
        openings in a building.
                7-5

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7.14.  If the emissions are in the form of a plume, the
inspector should note
   (a)  Whether the plume forms at the top of
        the stack or a few feet above the stack
        (a detached plume);
   (b)  The body of the plume and how far it rises
        before bending over; its shape after it
        bends over can be described as coning, fanning,
        or looping;
   (c)  The point at which it dissipates.  This may
        indicate whether the emission is smoke, fume,
        or contains water vapor.  A fume consists of
        relatively heavy molten liquid droplets that
        rapidly condense to a solid or a mist at a
        dissipation point that is closer to the stack
        outlet than is the case of smoke particles.
        The water vapor portion of a plume may evaporate
        leaving particulate matter that persists for a
        longer distance.
7.15.  For smoke emissions, the color is an indication
of the type of combustion problem or the type of fuel:
   (a)  Black or gray smoke indicates that the
        material is being burned with inadequate
        air or inadequate mixing of fuel and air.
   (b)  White smoke indicates either that the fire
        is being cooled by excessive drafts of air
        or that the materials being burned contain
        excessive amounts of moisture.
   (c)  Brown or yellow smoke indicates the burning of
        a semi-solid tarry substance such as asphalt
        or tar paper.  Generally, this fuel has not
        been raised to a temperature that is hot enough

                7-6

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        for best combustion and the mixing with
        air is inadequate.
   (d)  Blue smoke often results from the burning
        of trash which consists of paper or wood
        products.  The plume is composed of small
        liquid particles and contains only a few
        particles of carbon or soot.
7.16.  The inspector should make an initial identifi-
cation of a visible plume by placing it in one of the
following classes:
   (a)  Emissions from stationary combustion
        sources which are operated to produce
        energy;
   (b)  Emissions from mobile engines (e.g., gasoline,
          diesel, jet);
   (c)  Emissions that are primarily or totally
        water vapor;
   (d)  Emissions of particulate matter from
        industrial processes;
   (e)  Particulate emissions accompanying
      '  construction or demolition;
   (f)  Emissions of visible gases;
   (g)  Emissions from open-burning incinerators,
        agricultural burning, and structural
        building fires.
7.17.  The air pollution control officer should be
familiar with all of the sources of emission, the
process equipment, and the control devices located in
his area.
   (a)  Sources of visible plumes
        (1)  Steam-electric power plants

                7-7

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     (2)   Steam-generating facilities for
          institutions and schools
     (3)   Incineration equipment such as
          tepee burners, single-chamber and
          multiple-chamber incinerators, etc.
     (4)   Furniture, lumber, and wood products
          industry
     (5)   Cement plants
     (6)   Carbon black plants
     (7)   Soap and detergent manufacture
     (8)   Petroleum refineries
     (9)   Steel mills
    (10)   Asphalt batching plants
    (11)   Phosphate fertilizer manufacture
    (12)   Phosphoric acid manufacture
    (13)   Pulp and paper manufacture
    (14)   Lime plants
    (15)   Copper, lead, and zinc smelters
    (16)   Nitric acid manufacture
    (17)   Coke manufacture
    (18)   Gray iron foundries
    (19)   Vehicles powered by internal
          combustion engines
(b)   Manufacturing process equipment
     (1)   Furnaces
     (2)   Kettles
     (3)   Ovens
     (4)   Cupolas
     (5)   Kilns
     (6)   Dryers
     (7)   Roasters
     (8)   Towers
     (9)   Cookers
            7-8

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                            (10)  Digesters
                            (11)  Quenchers
                            (12)  Columns
                            (13)  Stills
                            (14)  Crucibles
                            (15)  Regenerators
                            (16)  Flares
                        (c)  Air pollution collection devices
                             (1)  Cyclones
                             (2)  Baghouses
                             (3)  Electrostatic precipitators
                             (4)  Wet collectors
                             (5)  Scrubbers
                             (6)  Dry centrifugal collectors
                             (7)  Venturi scrubbers
                             (8)  Afterburners
                             (9)  Fabric filters.
Suggested Additional Reading
                     Compilation of Air Pollutant Emission Factors,
                     Second Edition AP-42 (April 1973) and six sup-
                     plements dated 7/73, 9/73, 7/74, 1/75 and 4/76,
                     US Environmental Protection Agency, Office of Air
                     Quality Planning and Standards, Research Triangle
                     Park, NC 27711.
                     Control Techniques for Particulate Air Pollutants,
                     NAPCA Publication No. AP-51 Washington, DC (1969).
                     Available from National Technical Information Service,
                     Springfield, VA 22151.
                     "Identification of Effluent Plumes", in Field
                     Operations and Enforcement Manual for Air Pollution
                     Control, Vol. ±, USEPA.Publication No. APTD-1100,
                     Research Triangle Park, NC 27711 (1972).
                                     7-9

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CHAPTER VIII.
RINGELMANN CHART AND
EQUIVALENT OPACITY
                  8.1.  Regulations requiring that plume densities or
                  opacities not exceed a specified standard are logical
                  outgrowths of the original laws which prohibited
                  "excessive or repugnant"  as a nuisance.  It was a nui-
                  sance because it was "excessive or repugnant" to our
                  senses - sight, smell, and, possibly, touch.  Thus,
                  an acceptable method of determining whether a plume was
                  a nuisance was to set an emission standard based on
                  visual determination of the effluent—how dense or opaque
                  was the plume?
                  8.2.  It has been shown that with proper training an
                  inspector can evaluate the density or opacity of a
                  plume within 7.5 percent opacity, on the average, and
                  within 15 percent opacity for any individual reading,
                  as compared to measurements made by optical instruments.
                  When his training is supplemented by periodic retesting,
                  the inspector can maintain his plume reading proficiency.
                  Or this basis the courts have hpheld the Ringelmann and
                  Equivalent Opacity regulations when they are enforced
                  by qualified personnel.
                  8.3  Emission standards can relate to weight loading as
                  well . s optical density or opacity.  Compliance with the
                  latter type is easier and cheaper to check.  It requires
                  only that an inspector make.an observation for a
                  specified time period.
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8.4.  Although the visual standard is limited to
estimations of particles of pollution that obscure
vision, its application simultaneously tends to reduce
the total weight of all sizes of particles emitted.
Thus, the visual emissions standard can supplement the
weight loading standard and help to reduce the number
of source tests the latter standard would require.
8.5.  In some cases to comply with the opacity standard,
more efficient equipment operation or more efficient
combustion is required of a pollution source.  In other
cases more efficient air pollution control devices may
be necessary.  A general theoretical relationship
between plume opacity and particulate mass concentration
for several types of particles  (carbon, liquid water,
and iron oxide) for a particular source has been
developed.
EPA has established opacity limits for new source
performance standards of several industrial facilities
as well as mass emission limits primarily because it
believes that opacity limits provide the only effective
and practical method for determining whether emission
control equipment, necessary for a source to meet the
mass emission limits, is continuously maintained and
operated properly.  It has not been EPA's position that
a single, constant, invariant, and precise correlation
between opacity and mass emissions must be identified
for each source under all conditions of operation.
Such a correlation is unnecessary to the opacity
standard, since the EPA Administrator consistently
develops opacity standards for each class of source at
a level no more restrictive than the corresponding
mass emission limitation with due consideration given
to all conditions of operation.  Any source meeting the
mass limit will therefore also be meeting the opacity
limit.
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8.6.  An inspector's knowledge of the size distri-
bution of particle sizes and weights found in the stack
tests of various types of stokers, oil burners,
manufacturing processes, etc., may serve as a guide to
the relation between opacity and mass of effluent.
For example, if 75 percent of the weight of a plume is
in particles whose sizes are larger than 5 microns in
diameter and only 10 percent is in particles whose
diameters are less than 1 micron, then the portion which
is scattering light (0.4 to 0.7 micron) is small.  Under
these circumstances, compliance with the visual standard
may not ensure the compliance with the loading standard.
8.7.  The Ringelmann chart was developed about 1890
by Maximilian Ringelmann, a professor of agricultural
engineering in Paris.  It was introduced into the
United States in 1897 and first incorporated into law
in Boston in 1910.
8.8.  The chart is a method of judging the shade of
gray of a given smoke plume and was originally applied
to the emissions from coal-fired boilers.
8.9.  Many regulations state that it is illegal to
emit smoke of a darker shade than Ringelmann No. 2
for more than 3 minutes in an hour.  This 3-minute
grace period is allowed for starting up or soot
blowing.
8.10.  The State of California through its Air Pollution
Control Districts in 1947 extended visual emission
standards beyond the use of the Ringelmann chart for
gray-black plumes.  It also prohibited a plume of any
color if the plume's opacity was greater than that of
a plume with a shade of Ringelmann No. 2.
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8.11.  While there are actually two regulations which
cover all plumes, both black and nonblack, one regulation
could be sufficient for regulating the opaqueness of
any plume.  However, the Ringelmann standard historically
was established first and the equivalent opacity standard
was referred to the Ringelmann Chart.  Actually, the
inspector generally judges the amount of light trans-
mitted through both black and nonblack plumes and then
relates this transmission to Ringelmann Numbers as a
measure of the smoke density of gray-black smoke and
equivalent opacity percentages for colored or white
plumes.  If he compares the gray-black plume with a
Ringelmann Chart, he is equating the 60 percent of
light transmitted through a No. 2 plume with the 60
percent of light reflected by the No. 2 Ringelmann
Chart.  The term "equivalent opacity" refers to the
extension of the Ringelmann Chart to judge the degree
to which a visible plume of any color obscures the
view of the observer.  The statement of the equivalent
opacity regulation generally includes a clause stating
"such opacities as to obscure an observer's view to
a degree equal to or greater than does smoke of
Ringelmann No. 2 shade."  In its new source performance
standards, the EPA relates all visible emissions with
opacity only.  A few States and local agencies also
have dropped the use of the Ringelmann standard.
8.12.  The definitions of the terms "smoke density"
and opacity are the source of much controversy and
confusion by defense attorneys attempting to invalidate
the entire smoke-reading procedure.  The definitions
of these terms as they apply to visible emissions are
     (a)  Smoke Density - One definition of density
          is "the quantity per unit volume or area."
          Another is "the mass of substance per

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                             unit volume."  In visual emission
                             usage the first definition is the
                             correct one.  When applied to the
                             Ringelmann Chart, density refers to
                             the ratio of the area occupied by
                             the black grid lines to the total
                             areas of each card.  Since these
                             grid lines are opaque areas, the
                             smoke density is compared with opacity.
                             The definition is not meant to refer
                             to the weight per unit volume of the
                             plume.
                        (b)  Opacity - Opacity means the degree to
                             which transmitted light is obscured.
                             In air pollution, the expert reader
                             judges the amount of background, sky,
                             or light that he cannot see through the
                             emission.
The Ringelmann Chart
                   8.13.  The Ringelmann system is a method of reproducing
                   shades of gray by means of a rectangular grid of black
                   lines having fixed widths on a white background.  When
                   these grids are viewed from a distance, they appear to
                   form a uniform gray area.
                   8.14.  There are five equal steps between white and
                   black.  The grid lines are 10 mm apart for each card.
                   The spe< ifications for the square spaces between the
                   grid lines are
                        (a)  Card 0 - all white (100 percent of the
                             light transmitted)
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     (b)  Card 1 - black lines 1 mm thick,
          white spaces 9 mm square (81
          square mm) - 80 percent trans-
          mission
     (c)  Card 2 - black lines 2.3 mm thick,
          white spaces 7.7 mm square (59
          square mm) - 60 percent trans-
          mission
     (d)  Card 3 - black lines 3.7 mm thick,
          spaces 6.3 mm square (40 square
          mm) - 40 percent transmission
     (e)  Card 4 - black lines 5.5 mm thick,
          white spaces 4.5 mm square (20
          square mm) - 20 percent trans-
          mission
     (f)  Card 5 - all black - 0 percent
          transmission.
The actual chart as provided by the Bureau of Mines
contains only cards 1 through 4.
Since the accuracy required of the chart will not be
1 percent or less, the difference between 59 percent
and 60 percent can be considered negligible.
8.15.  The Ringelmann Chart published by the Bureau of
Mines is the chart that is referred to in air pollution
law.  This chart provides the shades of Cards 1, 2, 3,
and 4 in a single sheet.  These are known as Ringelmann
No. 1, 2, 3, and 4, respectively.
8.16.  If the chart is used while observing smoke, it
should be mounted 50 feet from the observer at which
distance the lines on the chart merge into shades of
gray.  The observer glances from the smoke, coming from
the stack, to the chart and notes the number of the

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                   card that most mearly corresponds with the smoke
                   shade.   When the correspondence is not exact, the
                   reading can be made to the nearest I/A Ringelmann
                   Number.  A clear stack is recorded as No. 0 and 100
                   percent black smoke is recorded as No. 5.
                   8.17.  With proper experience during a training period,
                   an observer can fix the shades of the Ringelmann Chart
                   in his memory.  The inspector may then make his
                   observations in the field without having a chart with
                   him.  The Superior Court of Los Angeles has compared
                   this to one's not needing "a color chart in his hands
                   to recognize a red flower, a blue sky, or a black
                   bird."
Smoke Reading Aids
                   8.18.  Although seldom used and difficult to obtain,
                   a number of smoke reading aids can be used to assist
                   in measuring the Ringelmann number of gray or black
                   smoke.  None have the versatility of a trained inspector
                   under varying conditions.
                   8.19.  Smoke Tintometer - This instrument used tinted
                   glasses graduated to the Ringelmann scale for comparison
                   with the smoke.  It contains two apertures, one for
                   observing the smoke and one for viewing the clear sky
                   through the opening or through one of the tinted
                   glasses.
                   8.20.  Umbrascope - This is a tube using tinted glass
                   segments which cover one-half of the field of view.
                   The smoke is seen through the other hald of the field
                   and is compared with the opacity of the glass.  One
                   thickness of the gray glass gives 60 percent opacity
                   and is equivalent to Ringelmann No. 3.  Additional
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thicknesses of glass give even greater opacity.  Thus,
no opacity less' than 60 percent can be measured with
this instrument.
8.21.  Smokescope - This instrument consists of two
barrels for receiving incoming light and one eyecup
for viewing.  The stack is viewed through one barrel
of the instrument.  Light from an area adjacent to
the stack enters the other barrel and illuminates a
circular standard density film.  Half of this film
is equivalent to No. 2 Ringelmann and the other half
is equivalent to No. 3 Ringelmann.  The image of these
two half disks is projected onto a screen in front
of the eyecup and this image surrounds a small aperature
where the smoke is seen.  The observer then compares the
smoke shade with the two Ringelmann shades.  The
advantage of this instrument over a Ringelmann Chart
used in the field is that the illuminations of the
smoke and the reference are both influenced by the
same factors.  One is not transmitted light while the
other is reflected.  Thus, the smokescope is automatic
compensation for varying light conditions.
8.22.  Film Strip - This is called a Smoke Inspection
Guide and consists of four densities:  20 percent,
40 percent, 60 percent, and 80 percent transmission.
The inspector views the source and matches it as closely
as possible with one of the densities on the guide.
8.23.  Smoke Comparison Charts - Several charts are
available and all of them work on the Ringelmann
principle.  They have shades of gray corresponding to
Ringelmann Numbers 1, 2, 3, and 4 printed on a small,
pocket-sized card that the inspector can carry with him.
When making comparisons with a plume the inspector
should hold the card at arm's length.
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8.24.  Photoelectric Cells - Photoelectric smoke-
metering equipment may be permanently built into a
stack.  This device measures variations in the
intensity of a beam of light passing through the
effluent in the stack.  As part of the granting of
a permit, these may be required to be mounted on a
stack for continuously monitoring the emissions.  In
these devices, a constant light source is used to
illuminate, a standard photoelectric cell that is
located on the opposite side of the stack.  The light
must pass through any smoke rising in the stack before
it reaches the cell on the opposite side.  The photo-
electric cell produces a current of electricity that
is directly proportional to the amount of light falling
on the cell.
The main problem with most of these devices is in trying
to periodically zero the photocell, especially in
continuously operating stacks.  Emission buildup on
the light source and on the photocell also creates a
problem.
8.25.  All of these smoke-reading aids, except the
photoelectric call, can be used only with the black-
gray plumes.  There are no aids in this nature for
assisting the inspector in judging those plumes which
fall under the equivalent opacity regulation.
8.26.  The Smoke Reading Aids are sometimes cumbersome
and are generally not significantly more accurate than
sight reading in establishing opacity violations.
8.27.  The lidar (or laser radar) instrument has been
proposed as a method of measuring smoke-plume opacity.
The lidar is composed of a laser transmitter that emits
a very brief, high-intensity pulse cf coherent light
and a receiver that detects the portion of this light
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                   being back-scattered to the instrument from the aero-
                   sols in the atmosphere.  When plume opacity is measured,
                   the lidar light is shot through the plume and is
                   scattered backward by the aerosols.  The receiver
                   measures the amount of reduction in the intensity caused
                   by the two passages of the light through the plume.   At
                   present, this instrument is still quite expensive for
                   routine usage.


Training of Inspectors
                   8.28.  Enforcement agencies have found it possible to
                   train observers to recognize Ringelmann numbers and
                   percent opacities without having a comparison chart
                   before them.  The inspectors are taught to judge the
                   plume shade or opacity by relating it to percent of
                   light transmission of a training plume.  The training
                   plume is generated by special equipment that regulates
                   the opacity of the plume and measures the opacity by a
                   photocell arrangement in the stack of the generator.
                   8.29.  Training with the smoke generator begins by
                   familiarizing the students with known densities of
                   black and white smoke.  Upon the sound of a horn the
                   instructor calls out the meter reading.  He will go up
                   and down the Ringelmann and Equivalent Opacity scales.
                   8.30.  Next, the students are given a practice run of
                   25 black and 25 white shades of smoke.  At the comple-
                   tion of this run, a student can grade his performance
                   and determine whether he was reading high or low.
                   8.31.  After these familiarization and practice runs,
                   the students are ready for testing for record.  Re-
                   peated runs of 25 white and 25 black shades of smoke
                   are made with the smoke generator.  In between test
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runs, short familiarization runs may be made to
reinforce the student's accuracy of judgement.
8.32.  A student keeps on observing the testing runs
until he qualifies as an expert smoke reader.  The
requirements are that he must read white and black
smoke with an average error not to exceed 7.5 percent
opacity in each category and with an error not to exceed
15 percent opacity (or 3/4 of a Ringelmann number) on
any reading in each category.
8.33.  Additional training may be allowed if the student
does not meet the standards.  However, if the student
is unable to pass the visible emissions test, he can
be disqualified from serving as an inspector.
8.34.  Training runs may be conducted under a variety
of conditions of lighting and background color to
simulate actual field conditions.
8.35.  To evaluate plumes at night it is necessary to
have a source of light behind the plume and to evaluate
the transmission of this light through the plume.
Nighttime readings should be made a part of the train-
ing program if the inspector will be required to make
field evaluations at night as part of his duties.
8.36.  Readings can also be made of smoke from tailpipes
or exhausts of moving vehicles.  The observer should
     (a)  Read the smoke at its point of
          maximum density;
     (b)  Use a stopwatch to record the
          accumulated violation time;
     (c)  Avoid reading directly into the
          long axis of the plume, if possible.
          It may be difficult to have a wide
          angle between his line of sight and
          the line of exhaust smoke.
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                        (d)  Take a photograph of the offending
                             vehicle and its plume.
Problems of Reading Smoke
in the Field
                   8.37.   There are several criticisms of visible emission
                   control regulations and the ability of inspectors to
                   enforce them objectively.  Many of these criticisms
                   can be overcome by the inspector's following proper
                   procedures in his field.
                   8.38.   Criticism:  The opacity or smoke density obser-
                   vation made by an inspector will vary according to the
                   position of the sun, the atmospheric lighting, the
                   background of the plume, and the size of the particles
                   in the plume.
                   Response:  The inspector should strive to make his
                   observations with the sun in the 140 degree sector to
                   his back, with the wind blowing at approximately
                   right  angles to his line of sight, and with a back-
                   ground that contrasts with the color of the plume.
                   Multiple observations under varying atmospheric conditions
                   can also be made to reduce the effects of the back-
                   ground and atmospheric lighting.  An experienced
                   observer can learn to weigh the opacity conditions in
                   relation to various conditions.
                   On the other hand, wide variations of the sizes of
                   particles in a plume will affect the light-scattering
                   potential of the plume.  In most cases it is the varia-
                   tion in mass emission rates that affect the opacity.
                   8.39.   Criticism:  Opacity and smoke-density measure-
                   ments  have not been correlated with other measurement
                   methods.
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Response:  For two types of particles, D. S. Ensor
and M. J. Pilat have developed a relationship between
plume opacity and a combination of the following
properties:  plume diameter, particle size distribution,
particle mass concentration, average particle density,
and particle refractive index.  Thus, their equation
includes more variables than plume opacity and mass of
emissions; however, if certain assumptions are made,
predictions of plume transmittance can be related to
particulate mass concentration.  The observer should
have a knowledge of the processes emitting a visible
plume so that he can make a judgment of how normal its
appearance is.  Its appearance may vary with the se-
quence of startup operations or with the atmospheric
relative humidity.
It is reasonable to assume that the elimination of
visible emissions will reduce dust and aerosol emissions;
however, the reduction may not be in the same ratio.
The small particles between 0.1 and 1 micron that
cause the light scattering require more expensive
control equipment than the large particles (greater
than 10 microns), which obscure light by absorbing it.
8.40.  Criticism:  Gaseous emissions cannot be deter-
mined by visible observations.
Response:  Very few gases are visible, consequently,
visible emission regulations can constitute only a
portion of a full set of air pollution regulations.
The opacity of a reddish-brown plume of nitrogen dioxide
gas from a nitric acid plant will indicate the amount
of that pollutant that is being emitted.  A bluish plume
for a boiler burning fuel oil will be an indication of
the high sulfur content of the oil.
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8.41.  Criticism:  Visible-emission observations are
difficult to apply at night.
Response:  If the observer positions himself so that
there is a source of light behind the plume or places
an auxiliary light source behind a plume, then he may
make readings at night.
8.42.  Criticism:  A wet plume may be judged as opaque
although its opacity is really due to the water droplets,
which are not considered as pollutants.
Response:  Since uncombined water is not normally con-
sidered as an air pollutant, some allowance must be
made for those visible plumes whose opacity is derived
from uncombined water droplets.  One method is to
require that opacity readings of a wet or steam plume
be taken at that point of the plume where the steam
has evaporated.  If the inspector suspects that the
source is in violation, it may be necessary to wait
for a hot, dry day when the steam rapidly dissipates.
He can then make his observation closer to the stack.
8.43.  Criticism:  Visible-emission regulations can be
circumvented by a polluter if he adds more air to his
effluent or builds a new stack of smaller diameter for
emitting the same quantity of effluent.
Response:  The adding of auxiliary air to the effluent
in the stack will reduce the concentration of the
pollutant and will reduce the opacity of the plume.
The adding of air to the plume to obtain a lower
concentration is specifically prohibited in "circum-
vention" clauses of some regulations.  These prohibit
the building and operation of equipment that tends to
conceal the emission.
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                    By decreasing the radius of the stack, the distance
                    through the plume will decrease and, since the velocity
                    of the emission increases, the concentration of the
                    effluent through the plume will remain the same.  The
                    result is that since the light will pass through a
                    thinner plume, less light will be scattered and the
                    observer will read a lower opacity.
                    A narrower stack may not fall under the circumvention
                    clause.  In this case it may be necessary to order a
                    source test to determine if there is a violation of a
                    process weight, emission weight, or concentration
                    ordinance.
                    It is also possible that the most opaque portion of the
                    plume may occur at some distance above the stack where
                    the emission loses its buoyancy.  The best time for
                    observing such a condition would be a day with little
                    or no wind.
                    8.44  Criticism:  Visible emissions from a point
                    source within a building cannot be read within the
                    building.
                    Response:  The observer should be able to read visible
                    emissions within a building the same way he makes
                    readings at night.  There may be some legality involved
                    whether or not local regulations allow this.  Los
                    Angeles County gets around this by stating in their
                    regulations that emissions within a building is consid-
                    ered emissions to the open atmosphere.
Advantages of Visible
Emission Regulations
                    8.45  Observers can be trained in a relatively short
                    time and it is not necessary that observers have an
                    extensive technical background.
                    8.46.  One man can make many observations in a day.
                    8.47.  No expensive equipment is required.
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                   8.48.   Violators can be cited without resorting to time-
                   consuming and costly source testing.   A particulate
                   source test takes a minimum of 1  day  for a single stack
                   plus the time needed for laboratory analysis  and report
                   writing at a minimum cost of $1,000 per source.
                   8.49.   Questionable emissions can be  located  and then
                   the actual emissions determined by source tests, if
                   necessary.
                   8.50.   Control can be achieved for those operations not
                   readily suitable to regular source testing methods,
                   such as leakage from equipment and buildings; loading
                   of grain, coal, and ores; or visible  automobile or truck
                   exhaust.
Suggested Additional Reading
                   "Ringelmann Smoke Chart,"  U.S.  Dept.  of the Interior
                   Information Circular 8333,  (1967).   Publications Center,
                   Bureau of Mines,  4800 Forbes Ave.,  Pittsburg,  PA.   15213.
                   Optical Properties and Visual Effects  of Smoke Stack
                   Plumes, W. D.  Conner and J. R. Hodkinson.   PHS Publi-
                   cation No. 999-AP-30, DREW, Research Triangle Park,
                   N.C.   27711 (1972).
                   "Plume Opacity and Particulate Mass Concentration,"
                   M.  J.  Pilat and D. S. Ensor, Atmospheric Environment,
                   Vol.  4, pp. 163-173 (1970).
                   "Calculation of Smoke Plume Opacity From Particulate Air
                   Pollutant Properties,"  D.  S.  Ensor and  M.  J.  Pilat,
                   Presented at 63rd Air Pollution  Control  Association
                   Meeting in St. Louis, Missouri,  June,  1970.
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"The Relationship Between the Visibility and Aerosol
Properties of Smoke Stack Plumes,"  D. S. Ensor and
M. J. Pilat, Presented at the Second International
Union of Air Pollution Prevention Associations in
Washington, D. C. (December, 1970).
EPA Response to Remand Ordered by U. S. Court of Appeals
for the District of Columbia in Portland Cement
Association v. Ruckelshaus, EPA-450/2/74/023 OAQPS
Research Triangle Park, N. C.  27711 (November, 1974).
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CHAPTER IX.
QUALIFICATION PROCEDURES AND
EXERCISE IN RECORDING FOR
QUALIFICATION
                   9.1.  The proficiency test requires the inspector to
                   observe 25 shades of black smoke and 25 shades of white
                   smoke.
                   9.2.  To qualify, the inspector must read each shade
                   with no deviations greater than 15 percent opacity or
                   3/4 of a Ringelmann number.  His average deviation must
                   be no more than 7.5 percent opacity for each category.
                   9.3.  The field portion of this course consists of read-
                   ing series of 25 black and 25 white shades of smoke
                   produced by the smoke generator.
                   9.4.  There will be some familiarization runs of both
                   black and white smoke during which the opacity or
                   Ringelmann number will be announced while the smoke is
                   being emitted.
                   9.5.  There will then be a practice run of 50 smoke
                   emissions.  Twenty-five black shades will be run follow-
                   ed by 25 white shades  Or vice versa.  The student will
                   record his observations to the nearest 1/4 Ringelmann
                   number or the nearest 5 percent equivalent opacity.  At
                   the conclusion of the 50 emissions, the student will
                   compare his readings against the transmissometer readings,
                   record his deviations, and complete his average deviation.
                   9.6.  Following the practice run there will be repeated
                   runs of 50 emissions during which the student will try
                   to refine his smoke-reading ability until he meets the
                   requirements of average deviation not to exceed 7.5
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                   percent opacity for each category,  and no reading
                   deviating more than 15 percent opacity (or 3/4
                   Ringelmann).
                   9.7.   A Smoke School Training Form will be used to
                   record the readings and deviations and to compute the
                   information required for qualification.  It also has
                   spaces for information regarding the observer, the
                   time of day,  the weather, and the observer's position
                   in relation to the wind direction, the sun, and the
                   background for the smoke.
                   9.8.   This form must be filled in completely when it is
                   submitted to the examiner by the student who has quali-
                   fied on a series of emissions.
Instructions to the Student
During the Reading of Smoke
                   9.9.  The aim of the training and testing of smoke
                   readers in this course is to produce an inspector whose
                   judgment of plume density will be accurate and unaffect-
                   ed by variable field conditions.  His expert observations
                   serve in place of the measurements of a mechanical device,
                   and his accuracy must stand up if the case is brought
                   to court.
                   9.10.  To aid the accuracy of inspectors and to promote
                   uniformity among inspectors' readings, several rules of
                   smoke reading should be followed while the smoke reader
                   is making his observations:
                        (a)  The sun should be within a 140
                             sector behind the observer during
                             daylight hours.  This avoids the
                             problems arising from the forward
                             scattering of light by the particles
                             in the plume.
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(b)   A light source should be behind
     the plume at night.
(c)   Readings should be made at
     approximately right  angles to
     the wind direction,  and from any
     distance necessary to obtain a
     clear view of the stack and back-
     ground.  This might  be from 100
     feet to 1/4 mile in  the case of
     stacks in the field  but not
     closer than 50 feet  in the case
     of observing the plumes from the
     smoke generator.
(d)   For plumes not containing water
     vapor, the inspector should estimate
     the plume density at a point only a
     foot or two above the stack at which
     height the plume is  no wider than the
     diameter of the stack.  The inspector
     should make his observations of water
     vapor plumes in accordance with local
     ordinances.
(e)   The inspector should try to read the
     plume against a contrasting background
     such as blue sky for black plumes and
     tree leaves for white plumes.
(f)   The inspector should not stare at the
     plume, but should look at it only at
     the prescribed 15 second interval.
     Staring at the plume will cause fatigue
     and produce erroneous readings.
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                   9.11.   During the inspector's training and testing with
                   the smoke generator,  a horn will be sounded when he
                   should look at the plume and make his observation.  In
                   between the soundings of the horn he should not stare
                   at the plume.  The time interval between the sounding
                   of the horn and the glancing at the stack top by the
                   observer is approximately the time it takes the generator
                   smoke to travel from the generator's transmissometer to
                   the top of the stack.
                   9.12.   If the local agency permits it, the inspector may
                   use small, hand-held Ringelmann Charts or other aids as
                   guides in judging the black and gray shades.
                   9.13.   The inspector should not wear dark glasses while
                   taking the test unless he plans to wear these glasses
                   while making smoke readings in his normal enforcement
                   and inspection duties.
Filling Out the Training Form
                   9.14.  Name and Affliation of the observer are self-
                   explanatory, as is the Date of the test.
                   9.15.  The Time should be the approximate time when the
                   switch between black and white smoke was  made.
                   9.16.  Location refers to the address and city where the
                   test was given.
                   9.17.  The Wind Speed should be estimated by the observer
                   within a 3 to 5 mile-per-hour range.  If  an anemometer
                   (wind speed instrument) is not available, he may estimate
                   the wind speed by using the Beaufort wind scale.
                                  9-4

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9.18.  To determine the Wind Direction the observer
must first know his orientation with respect to north.
This can be learned from a map.  The direction from which
the wind is blowing can then be estimated to 16 points
of the compass (N, NNE, etc.) by watching a 2lag or
seeing which way a handful of grass blows when thrown
into the air.
9.19.  Sky Condition should be filled in as:
     (a)  Clear - less than 0.1 of the sky
          covered by clouds;
     (b)  Scattered - 0.1 to 0.5 of the sky
          covered;
     (c)  Broken - 0.5 to 0.9 of the sky
          covered;
     (d)  Overcast - more than 0.9 of the
          sky covered.
9.20.  Observer's Position should show his position in
relation to the sun, the smoke generator, and the
plume.
9.21.  Run No. - Each run during the training session
will consist of 25 black (B) and 25 white (W) shades of
smoke.  The runs will be numbered successively be-
ginning with 1-B and 1-W.
9.22.  The student will enter his observations in the
Observer's E.eading columns.  The black smoke readings
should be entered as fractions of Ringelmann Numbers,
with 0 being the lowest and 5 being the largest.  The
minimum increment is 1/4.  If appropriate in relation
to the laws or regulations of the jurisdiction in which
the students work, the observations of black smoke may
be recorded in opacity, to the nearest 5 percent.  The
                 9-5

-------
white smoke readings should be entered in percent
opacity.  The lowest possible reading is 0 and the
highest is 100.  The observations are made to the
nearest 5 percent.
9.23.  At the end of the run the instructor will read
off the transmissometer readings and the student should
enter these values in the Transmissometer Reading
columns.
9.24.  The student will then fill out the Deviation
columns.  If the observer's reading is less than the
transmissometer readings, the difference is entered in
the - Deviation column.
9.25.  In computing the deviations for the black smoke
readings, it will be more convenient to convert the
fractional Ringelmann number differences into percents,
similar to the white smoke.  A deviation of 1/4
Ringelmann is equivalent to 5 percent, 1/2 to 10 per-
cent, 3/4 to 15 percent, 1 to 20 percent, and so on.
As can be seen, these conversions to percentages are
done by multiplying the Ringelmann deviations by 20.
9.26.  The entries in the + Deviation and - Deviation
columns are added and their Sum is entered at the bottom
of the column.  The Number of deviations in each column
is also entered at the bottom of the column.  These
entries can be used by the student to guide him as to
whether he is tending to read high or low.  If he
divides the sum of his deviations by the number of
deviations, he can estimate how high or low he is
reading.
9.27.  In the QUALIFICATION portion of the form, the
two sets of boxes refer to the black and white portions
of the run.
                9-6

-------
                    9.28.  In the first set of boxes enter the run number.
                    9.29.  In the second set of boxes, enter the number of
                    readings on which the observer agreed exactly with the
                    transmissometer reading.
                    9.30.  In the third set of boxes, enter the number of
                    readings on which the observer disagreed with the trans-
                    missometer by more than 3/4 of a Ringelmann Number (black)
                    or by more than 15 percent equivalent opacity (white).
                    9.31.  Calculate the average deviation on the black and
                    then the white portion of the run by adding the sum of
                    the + Deviations to the sume of the - Deviations and
                    dividing this by the number of readings (25).
                    9.32.  The Examiner will verify the Training  Forms of
                    those students who will qualify.
                    9.33.  To qualify, the student must have no readings
                    of black or white smoke that deviate by more  than 3/4
                    of a Ringelmann Number or more than 15 percent equiva-
                    lent opacity, and his average deviation for white and
                    for black smoke must both be less than 7.5 percent.
Suggested Additional Reading
                    Guidelines for Evaluation of Visible Emissions,  R.
                    Missen and A. Stein.  EPA Contract #68-02-1390,
                    Publication No. 340/1-75-007, U. S. Environmental
                    Protection Agency, Washington, D.  C. (April, 1975).
                    "Smoke Reading School," in Field Operations and  Enforce-
                    ment Manuaii for Air Pollution Control, Volume 1, pgs.
                    4.28 - 4.32.  EPA Publication No.  APTD-1100, U.  S.
                    Environmental Protection Agency, Research Triangle
                    Park, N. C.  27711.
                                   9-7

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                    ENVIRONMENTAL PROTECTION AGENCY
                       VISIBLE EMISSION TRAINING FORM
1. Name of Observer
2. Affiliation	
3. Date	
            Time
4.  Wind Speed	
5.  Observers Position
6.  Corrected By	
Direction,
Sky Condition,
     Record Black and/or White Smoke in Percent Opacity (for  example: 5 percent smallest division)
RUN NO.
o
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1
2
3
4
5
6
7
8
9
10
11
12
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Reading












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0
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13
14
15
16
17
18
19
20
21
22
23
24
25
I.E
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Transmissometer
Reading













+ Deviation 1













— Deviation













RUN NO.
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2
3
4
5
6
7
8
9
10
11
12
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Transmissometer
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-*• Deviation












—Deviation













d
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13
14
15
16
17
18
19
20
21
22
23
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 8. Number Correct
 9. Number of Plus Deviations
 10. Number of Minus Deviations

 11. Average Plus Deviations :  Sum of Plus Deviations
                             No. of Plus Deviations
 12. Average Minus Deviations =  Sum of Minus Deviations
                              No. of Minus Deviations
 13. Average Deviation ^ (Sum of Plus Deviations)  + (Sum of Minus Deviations)
         I  + (Si
         3. of Re
                                    Total No. of Readings

14. Number of Readings 20% Deviation and Over (or 1 Ringeimann and more)

                                             9-8
               7.

               8.

               9.

               10.

               11.

               12.

               13.

               14.

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CHAPTER X
BASIC METEOROLOGY
                    10.1.   Primary Meteorological  Factors Affecting Concen-
                    tration of  Air Pollutants-There  are  two meteorological
                    factors of  primary concern  in  the  life cycle of an air
                    pollutant.   These are wind  and stability.  As Figure  10-1
                    indicates,  we can think  of  wind  primarily as the horizon-
                    tal motions and fluctuations of  the  air, while stability
                    can be thought of as an  index  of vertical turbulence.
                    Since  the diffusion of pollutants  in the atmosphere is
                    basically dictated by the amount of  motion or turbulence
                    in the atmosphere around the source, we can begin to  see
                    very quickly why wind and stability  are of basic concern
                    to the air  pollution meteorologist.
  W|ND "DIRECTION
         'SPEED
                                     10-1

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Wind
                    10.2.  Meteorologists usually consider two obvious
                    factors in relation to wind.  They are wind direction
                    and speed.  When considering the winds at a particular
                    point or over an area, we need to remember that the
                    wind direction is the direction from which the wind
                    blows.  Figure 10-2 is a segment of a weather map
                    representing the weather conditions reported at several
                    stations.  Note the little  flag or arrow that extends
                    from the station circle at  Miles City, Montana.  This
                    points or flies from the northwest and tells us that the
                    wind is a northwest wind...a wind that blows from  the
                    northwest.  If you consider this as a "wind arrow" with
                    the  speed indicated by the  number and length of the
                    barbs, or "feathers," then  the arrow flies with the wind,
                    toward the station circle.
                    In studying the wind patterns-or wind climatology-for a
                    certain location, meteorologists construct what is known
                    as a wind rose.  A wind rose is a graphical representa-
                    tion of the percent frequency with which winds from a
                    certain direction occur.  On the wind rose shown as
                    Figure 10-3, note that the winds from the northwesterly
                    direction occur about 15% of the time, with winds from
                    the south and the south-southeast also occuring frequently.
                    This wind rose indicates that the prevailing winds are
                    from the south-southeast.   A wind rose,  then, provides
                    a picture of the patterns of wind direction.   Wind direc-
                    tion determines the source-receptor relationship in air
                    pollution.   More simply speaking,  wind direction deter-
                    mines who and what will be affected by emissions from
                   •sources.   Information about the frequency of  wind direc-
                    tion in a given area can be useful in basic planning
                    for the locations of industrial operations with respect
                    to residential areas.
                                     10-2

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          SURFACE WEATHER MAP
          AND STATION WEATHER
SURFACE WEATHER MAP
 AND STATION WEATHER
    AT 1:00 A. M., E. S. T.
                                  10-3

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      WIND ROSE
- PERCENT FREQUENCY
SEATTLE, WASHINGTON
       BOEING FIELD
       OCTOBER, 1962
      Figure 10-3
                  Wind speed  is  a  second consideration.  Table 10-1 is the
                  Beaufort  Scale of wind-speed equivalents.  A lay person
                  can estimate wind speed by this table.  Wind speed has
                  as great  a  significance as wind direction in how a
                  receptor  will  be affected as illustrated in Figure 10-4.
                  Low wind  speeds  or calm conditions will extend the "life
                  cycle" of pollutants by allowing various chemical and
                  photochemical  reactions to occur that produce secondary
                  pollutants.  Ground level concentrations of pollutants
                  will be lower when high winds bring in fresh air to di-
                  lute the  pollutants further.   Mechanical turbulence,
                  which results from winds moving over rough terrain,  can
                  increase  and will hasten the  gravitational settling of
                  particulate pollutants,  as well as speeding the  disper-
                  sion of pollutants in the atmosphere.   High wind speeds
                  are  generally favorable  for the dispersion and transport
                  of air pollutants.
                                 10-4

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                 Table 10-1




The Beaufort Scale of Wind-Speed Equivalents

General
Description

Calm


Light

Gentle

Moderate

Fresh




Strong



Gale



Whole gale

Hurricane


Specifications

Smoke rises vertically.
Direction of wind shown by smoke drift
but not by wind vanes.
Wind felt on face; leaves rustle;
ordinary vane moved by wind.
Leaves and small twigs in constant
motion; wind extends light flag.
Raises dust and loose paper; small
branches are moved.
Small trees in leaf begin to sway; crested
wavelets form on inland waters.
Large branches in motion; whistling heard
in telegraph wires; umbrellas used with
difficulty.
Whole trees in motion; inconvenience
felt in walking against the wind.
Breaks twigs off trees; generally
impedes progress.
Slight structural damage occurs (chimney
pots and slate removed) .
Trees uprooted; considerable structural
damage occurs.
Rarely experienced; accompanied by
widespread damage.

Miles per Hour
Limits of Velocity
33 feet (10 m)
above level ground
Under 1
1 to 3

4 to 7

8 to 12

13 to 18

19 to 24

25 to 31


32 to 38

39 to 46

47 to 54

55 to 63

64 to 75

Above 75
                10-5

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r~
                                SHORTEN TIME POLLUTANTS ARE
                                AVAILABLE FOR PHOTOCHEMICAL-
                                REACTION    "    —	-^
                                                  INCREASE MECHANICAL
                                                  TURBULENCE      ^
  Figure io-4ihe  volume  of  air  in  which  pollutants  can  be  diluted  is  directly
             proportional to  the wind  speed.
                      The wind around a particular point at a given time is
                      influenced by a number of forces.   Three factors are im-
                      portant in the flow of air:   the pressure gradient force,
                      the Coriolis effect, and the effects of surface features
                      and topography.
 Pressure Gradient Force
                      10.3.  Wind, or air flow, results basically from the presence
                      of high and low pressure systems.  Pressure,  in meteoro-
                      logical terms,  is simply the weight of the atmosphere.
                      Cool air weighs more than warm air.  A high pressure
                      system then, is a mass of cool,  relatively heavy air,
                      while a low pressure system consists of warm,  relatively
                      light air.   The rate and direction of the pressure differ-
                      ence between areas of high and low pressure is know as
                      the pressure gradient.  The pressure difference exerts
                      a force on  an air parcel, causing it to move from the
                      area of high pressure to the area of low pressure.  This
                      force is called the pressure gradient force.   Thus, winds
                      will tend to blow from a high pressure area to a low pres-
                                      10-6

-------
Coriolis Effect
                     sure area.  Figure 10-5-a shows the pattern of wind flow
                     related to the pressure gradient force.  Figure 10-5-b
                     shows this air flow from high to low pressure in a cross-
                     sectional view.  Air will tend to spiral out near the
                     surface of the earth from the center of a high pressure
                     system, and cool, heavier air from aloft will sink to
                     replace it.  Air will tend to spiral in toward the center
                     of a low pressure system, and this warm air will rise.
                     The pressure gradient force then, sets the air in motion
                     from an area of high pressure to an area of low pressure.
                     10.4.  The basic flow of air is deflected by the Coriolis
                     force.  In reality, this is not a force at all, but an
                     effect resulting from the rotation of the earth, and
                     the movement of air relative to the earth's surface.
                     From a fixed point on the earth, it appears to us that
                     there is a  force  that deflects winds  to  the right  in the
                     northern hemisphere,  and to the left in the southern
                     hemisphere.  So any wind flow caused by the pressure
                     gradient force will be  deflected or altered slightly
                     by this Coriolis  effect, as shown in Figure 10-6.
                     Please study Figure 10-7.  Imagine two winds  over  North
                     At erica,  a  wind blowing from the south along  the meridian
                     at 90 W and a wind blowing from the west along the parallel
                     at 40 N.  Four hours  later the earth has rotated to the
                     east 60 , one-sixth of  a total rotation.  To  an observer
                     from -»uter  space  the  wind directions have not changed.
                     They ,.ave maintained  their original absolute  direction
                     with respect to a point in space, while the earth  under-
                     neath has turned.  To an observer on the earth, however,
                     it appears  that these winds have bf-.en deflected to the
                     right.  And indeed, since the meridians and parallels
                     have rotated and changed absolute direction,  the original
                                     10-7

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     a.
            Weak gradient
  Clockwise flow around a
  high pressure area in     HIGH
  the Northern Hemisphere.
                                      Steep gradient
                                                             Surface winds —^
                                                             Wind above
                                                             3000 ft.	>•
      Counterclockwise  flow
      around  a  low pressure
LOW  area  in tne  Northern
      Hemisphere.
     Pressure gradient is the rate and direction of pressure change.  In the
     drawing abovf  (and on weather maps) the solid lines are isobars, lines
     of equal pressure.  Where the isobars are close together, the pressure
     change is rapid, and the pressure gradient is "steep" or high in magni-
     tude.  Here  the pressure gradient will exert a greater accelerating
     force, and there will be greater wind speed.  Weak winds can be associ-
     ated with widely spaced isobars, where there is a weak gradient.  The
     direction of the wind flow is from high to low pressure.  But the rota-
     tion of the earth will cause this wind flow to be indirect.
     b.
                HIGH
              PRESSURE
    Flow of air from a high pressure area to a low pressure area caused by the
    pressure gradient force.

                                    Figure 10-5
L
                                      10-8

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             DEFLECTION
                 TO THE RIGHT IN THE
                 NORTHERN HEMISPHERE
                 TO THE LEFT IN THE
                 SOUTHERN HEMISPHERE
              Figure 10-6
              Deflection of the winds by the Coriolis effect,
8=OO AM                           12=OO N
   A                                 B

   Figure 10-7  Coriolis force.illustrated.
                    10-9

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                    south wind now appears to be from the southeast, and  the
                    west wind is now from the northwest.  Thus  the Coriolis
                    force, or the Coriolis effect as it can more accurately
                    be called, is the deflecting force of the earth's rota-
                    tion, which causes winds, and all other moving objects,
                    to appear to be deflected to the right of their direction
                    of movement in the northern hemisphere, and to the left
                    in the southern hemisphere.
                    This is a rather difficult concept to really understand.
                    However, you should remember that a given air flow re-
                    sulting from the pressure gradient force will be deflected
                    to the right in the northern hemisphere.
Topographical Features
                     10.5.  To this point, two basic influences acting on the
                    winds have been presented:  the Coriolis effect  (a global
                    or macroscale phenomenon), and the pressure gradient force
                     (a synoptic or continental scale phenomenon).     On a still
                    smaller scale, the direction and force of the winds near
                    the surface of the earth are influenced by the presence
                    of topographical features, buildings, and bodies of water.
                    Some of these are shown in Figure 10-8.  This friction, or
                    drag, of the surface features tends to slow the  winds and
                    change the direction of their flow, so that there are
                    frequent local variations from the basic flow set up by
                    the pressure gradient force.  There are, then, at least
                    three effects acting on the winds, ranging from  the
                    largest to the smallest scale of motion - the Coriolis
                    effect, the pressure gradient, and the topographical
                    features.
                                   10-10

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Figure  10-8  Friction and drag of topographical features also act to change
             and influence the winds on a local or regional basis.
Stability
                     10.6.  The second meteorological parameter of basic con-
                     cern to the air pollution expert is stability.  Stability
                     is defined as the tendency of the atmosphere to enhance
                     or suppress vertical motions.  The amoun': of vertical
                     motions.  The amount of  vertical motion in the atmos-
                     phere over a polluted area will, in part, determine
                     hovr quickly and effectively these pollutants are dis-
                     persed through the atmosphere.  An index of vertical
                     motion can be determined by investigating how the
                     temperature changes as we ascend in the atmosphere.
                     This Is usually done at weather stations by releas-
                     ing a radiosonde  (Figure 10-9).  This box carries sen-
                     sors and a radio  transmitter.   As the radiosonde
                     ascends through the atmosphere it  ^ends back informa-
                     tion about temperature, pressure, and humidity at
                     various altitudes.
                                     10-11

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            BOX  CONTAINING
            INSTRUMENTATION
            INCLUDING  PRESSURE,
            TEMPERATURE, AND
            HUMIDITY SENSING
            ELEMENTS.
                           Figure 10-9  Radiosonde
—RADIO TRANSMITTER
 What  sort  of  picture  emerges  from these  readings?  -
 Normally,  the air  near  the  earth's surface  is  slightly
 warmer  than that aloft.   The  warmer,  lighter air will
 rise, and  the cooler, heavier air will sink and re-
 place it.  This causes  an overturning or mixing in the
 air,  which provides a large volume of air in which to
 mix pollutants.  Meteorologists  call  this rate of  temper-
 ature change  the lapse  rate.   In order to represent the
 lapse rate graphically,  the meteorologist plots a
 temperature profile  (Figure 10-10).   In  such a profile
 the temperature is plotted  against altitude and
 the slope  indicated  as  a solid line called  the environ-
 mental  lapse  rate.  The dotted line is  the  "standard"
 lapse rate.   The "standard" lapse rate represents  a
               10-12

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                                 Figure 10-10
    2,000
Ol
-a
-(->
    1,000
REPRESENTS "STANDARD" LAPSE  RATE
(REFERRED TO AS THE  DRY ADIABATIC
LAPSE RATE) - 5.4°F  PER 1000 FEET
ALTITUDE.
REPRESENTS AN ENVIRONMENTAL  LAPSE
RATE OR ACTUAL CHANGE WITH HEIGHT.
         45  46  47  48  49  50  51  52 53 54 55 56  57  58
             Temperature in degrees fahrenheit
                     drop of 5.4  Fahrenheit for each  1000  feet  increase in
                     altitude.   When the measured or environmental  rate is
                     the same as this standard decrease in  altitude tempera-
                     ture,  the parcels of air at any height in that environ-
                     ment are in equilibrium, and will not  tend  to  rise or
                     subside unless some outside force is applied.   If  you
                     think of typical weather patterns, you can  easily  be-
                     gin to imagine conditions under which  there will be un-
                     stable conditions because of a large difference between
                     ground level temperature and temperature aloft.  In mid-
                     afternoon on a clear day, the air near the  surface
                     will be very warm because the earth is giving  off  the
                     heat it has absorbed from the sun.  Thus, there will be
                     overturning, often called thermal turbulence.   A slightly
                     different condition often occurs when  there is a cloud
                     cover or windy conditions, and the ground does not re-
                     ceive as much heat, as shown in Figure 10-11.   Here,
                     the air near the ground stays nearly the same  tempera-
                     ture as the air aloft during the day and does  not  cool
                     off as much at night.  This is called  a weak lapse rate.
                     There is still moderate mixing and dispersion  of pollu-
                     tants, enhanced by the likelihood of high winds.
                                   10-13

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  1.000
0)
TD
3
   500
                       ENVIRONMENTAL
                       LAPSE RATE  IS
                       SLIGHTLY STABLE
                           MODERATE
                           DISPERSION
     43«
      5V
Temperature (F)
                                   53°
                                            49"F
                                          COOL AIR
                                    Figure 10-11
                      Consider Figure 10-12.   This shows what happens as the
                      sun sets on a clear day.   The ground will begin to cool
                      off rapidly,  much more  rapidly than the air above it.
                     A layer of cool air will form near  the ground.  As  the
                     night continues, the cool layer of  air will extend  fur-
                     ther into the atmosphere.  Pollutants emitted into  this
                     cool air will remain near the surface of  the earths since
                     they are essentially trapped under  the warm layer of air
                     into which they cannot rise.  This  condition is called
                     an inversion, since the normal temperature structure is
                     inverted.  When the sun rises again on such a clear day,
                     the solar radiation will quickly heat the surface of the
                     earth,  warming the layer of air in contact with it. This
                                    10-14

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                                                           23°
                                                        COOLER AIR
20°
            \
 ENVIRONMENTAL LAPSE
-RATE  IS INVERTED IN
 COMPARISON  WITH  THE
 NORMAL  STRUCTURE -
 POOR  DISPERSION
                                                           28°
                                                        WARMER AIR
                                                           28°
                                                      	20°
                                                         COOL AIR
             \
               \
               J5°
                             30°
          Temperature  (F)
                               Figure  10-12
              warm air will mix with cool air aloft, soon eliminating
              the  cold inversion  layer.  Usually within two or  three
              hours after  sunrise, we will have returned to the un-
              stable temperature  structure as shown in Figure 10-13.
              In such unstable atmospheric conditions, good vertical
              mixing will  occur.  This cycle may be altered by  stir-
              ring of the  atmosphere with high winds, or by presence
              of clouds  or precipitation, which will make both  day-
              time mixing  and nighttime  inversions less extreme.
              We can watch a plume or stream of smoke emitted from a
              large source of pollution  and observe its behavior  to
              determin   whether conditions are stable or unstable.
              Figure 10-15 illustrates three of these plume types.
              When we have very unstable conditions, there is a
              great deal of mixing and overturning in the atmosphere.
              The  plume  in this case will  take the eaape of the
              overturning  eddies, and will form what we call a  "looping"
                                10-15

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      1,000
           .     \   ENVIRONMENTAL
          \       \  LAPSE RATE IS
                     UNSTABLE
   -a
    3
\ GOOD DISPERSION
                                                  N
                              COOL AIR
                                 52o
\
         32°       35°             60°
               Temperature (F)
                                    Figure  10-13
  -1,000
•O
   500
                         INVERSION ALOFT
                                                            MODERATE  DISPERSION
         SURFACE INVERSION    \
     60°                      63"
             Temperature(F)
                                  Figure 10-14
             	  REPRESENTS "STANDARD" LAPSE  RATE  (  REFERRED TO AS THE DRY
                   ADIABATIC LAPSE RATE) - 5.4°F  PER 1000 FEET ALTITUDE.
                   REPRESENTS THE ENVIRONMENTAL LAPSE  RATE.
                                     10-16

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plume.  This will result, as you would expect, in very
rapid mixing and good dispersion, although high ground-
level concentrations will result near the source when a
plume actually reaches the surface.  When the atmosphere
becomes more stable, the tendency for overturning de-
creases, and we will see what is known as a coning
plume.  Here, the amount of spreading out in the hori-
zontal and vertical directions are about the same, and
dispersion is fairly good.  In an inversion situation,
the atmosphere resists vertical mixing, and a plume
emitted into the atmosphere will stay very near the
level at which it is emitted.  This is a "fanning"
plume.  There are two additional plumes, lofting and
fumigation, which are not discussed here.  Please refer
to Table 10-2 for a detailed outline of the conditions
and the associated behaviors of the five plumes.  As
depicted in Figure 10-14 an inversion can occur near the
surface or aloft.  Emissions from ground-level sources
will stay within the surface inversion layer.  (We fre-
quently see this situation in the early morning hours,
when there is heavy traffic and the exhaust fumes are
trapped in a surface inversion).
 A high stack is an advantage in an area where there are
 frequent surface inversions, since pollutants emitted
 above the inversion level will stay at that level,  and
 ground-level concentrations from that source will gen-
 erally be minimal.   With a little practice, you can
 learn the trick of judging the dispersion capacity of the
 atmosphere by watching the behavior of plumes.
 Meteorologists use a concept called mixing depth, or
 mixing height to quantitatively represent the disper-
 sion capacity of the atmosphere.   Mixing height simply
 refers to the height to which vigorous vertical mixing
 takes place.   Meteorologists have devised a method  of

               10-17

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UNSTABLE  LAPSE
    RATE
                          o-	
SLIGHTLY STABLE
LAPSE RATE
                                            VERTICAL MIXING ENHANCED
                                           r;ON! NG  PLU ME
                                            MODERATE MIXING
INVERTED LAPSE
    RATE
                                            FANNING PLUME
                                            VERTICAL MIXING
                                            SUPPRESSED
                               Figure 10-15
                     forecasting the maximum mixing height which can be ex-
                     pected  on a given day, so that they can anticipate
                     whether or not high concentrations of  pollutants are
                     likely  to occur.
                     Figure  10-16 shows two different mixing heights.  If the
                     same  emissions of pollutants were found in both situa-
                     tions,  you would expect a much higher  concentration of
                     pollutants in the second instance, since there is a smaller
                     volume  within which the pollutants can be diluted.  There
                     are significant differences in the seasonal averages for
                     mixing  height at most locations.  During the summer day-
                     light hours, the mixing height may extend up to several
                     thousand feet.  In the winter,  when less heat is received
                     from  the sun, the mixing height may be as low as a few
                                 10-18

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                                  Table 10-2

                      PLUME BEHAVIOR AND RELATED WEATHER
LOOPING
Description

 Irregular  loops and waves with random sinuous movements; dissipates in
 patches;  relatively rapid with distance.
Temperature Profile-Stability

Adiabatic  or4 super-adiabatic  lapse  rate
— unstable.
Height
                                                      Temperature-
Typical Occurrence

 During  daytime with clear or partly cloudy skies and intense solar heating;
 not  favored  by layer-type cloudiness, snow cover or strong winds.
Associated Wind and Turbulence

 Light winds with intense thermal  turbulence.
Dispersion and Ground Contact

 Disperses  rapidly with  distance;  large  probability  of high concentrations
 sporadically at ground  relatively close to  stack.
Ground Level Patterns
                                    10-19

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Table 10-2 (continued)
  CONING
  Description
  Roughly cone-shaped with horizontal axis; dissipates farther down-wind
  than looping plume.
  Temperature Profile - Stability
   Lapse  rate between dry  adiabatic  and
   isothermal-neutral or stable.
Height
                                                             \
                                                             i • \
                                                        Temperature —
  Typical Occurrence
   During windy conditions, day or  night;  layer-type cloudiness  favored  in
   day; may also occur briefly in a gust during  looping.
  Associated Wind and Turbulence
  Moderate to strong winds; turbulence largely mechanical rather than thermal
  Dispersion and Ground Contact
  Disperses less rapidly with distance than looping plume, large probability
  of ground contact some distance downwind; concentration less but persisting
  longer than that of looping.
  Ground Level Patterns
              Top view   _
              of Stack   °
                                      10-20

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 Table  10-2  (continued)
 FANNING
Description                     =
 Narrow horizontal  fan;  little or no  vertical  spreading;  if  stack  is high,
 resembles a meandering  river, widening  but  not  thickening as  it moves
 along; may be seen miles  downwind;  if effluent  is warm,  plume rises slowly,
 then drifts horizontally.

Temperature Profile - Stabilty
 Inverted or isothermal  lapse  rate - very
 stable
                                              Height
                                                      Temperature
Typical Occurrence

 At night and in early morning, any season; usually associated  with  inversion
 layer(s); favored by light winds, clear skies and snow cover.
Associated Wind and Turbulence

 Light winds;  very little  turbulence.
Dispersion and Ground Contact
 Disperses  slowly;  concentration  aloft  high  at  relatively great distance down
 wind; small  probability of ground  contact,  though  increase  in turbulence can
 result in  ground  contact;  high ground  level  concentrations  may occur if
 stack is short or  if plume moves to  more  irregular terrain.
                                     10-21

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 Table  10-2  (continued)
   LOFTING
  Description

   Loops or cone with well  defined bottom and  poorly  defined, diffuse  top.
  Temperature Profile - Stability

   Adiabatic lapse rate at stack top and
   above; inverted below stack—lower
   layer stable, upper layer neutral or
   unstable.
Height
                                                        Temperature —
  Typical Occurrence

   During change from lapse to inversion condition;  usually  near  sunset  on
   fair days; lasts about an hour but may persist  through  night.
  Associated Wind and Turbulence

i   Moderate winds and considerable turbulence aloft;  very  light  winds  and
   little or no turbulence in layer below.
  Dispersion and Ground Contact

   Probability  of ground contact small unless inversion layer is shallow and
   stack  is short;  concentration high with contact, but contact usually pre-
   vented by  stability  of  inversion layer; considered best condition for
   dispersion since pollutants are dispersed in upper air with small probability
   of  ground  contact.
                                      10-22

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Table 10-2 (continued)
 FUMIGATION
Description

  Fan or cone with well defined top and ragged or diffuse bottom.
Temperature Profile - Stabilty

 Adiabatic or super-adiabatic lapse
 rate at  stack top  and below; isothermal
 or  inverted lapse  rate above - lower
 layer unstable or  neutral, upper layer
 stable.
Height
        Temperature
Typical Occurrence

  During change from inversion  to  lapse  condition;  usually nocturnal inversion
  is being broken up through  warming  of  ground  and  surface layers by morning
  sun;  breakup commonly begins  near ground and  works  upward,  less rapidly in
  winter than  in summer; may  also  occur  with  sea breeze  in late morning or
  early afternoon.
Associated Wind and Turbulence

  Winds light to moderate  aloft,  and  light  below;  thermal  turbulence in lower
  layer,  little turbulence in  upper layer.
 Dispersion and Ground Contact

  Large probability of ground contact in relatively high concentration,
  especially after plume has  stagnated aloft.
                                     10-23

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             _ _MI_XING_ HEIGHT
              65°F
            COOLER AIR
                             O
o
oo
                                        COOLER AIR
                                          22°F
                                        WARMER AIR
                                           27°F
                                   MAXIMUM MIXING HEIGHT
     WARM AIR
       75°F.
CLEAR SUMMER DAY
                                         INVERSION CONDITIONS ON
                                               A WINTER  DAY
            Figure  10-16   Mixing  Heights
           hundred feet.  The mixing height will also vary in the
           course of a day.  Morning and afternoon mixing  heights
           are calculated each day for the major weather stations
           around the country.  The mean, or average, wind speed
           through the mixing depth is also calculated (Figure 10-17),
           When these two critical meteorological parameters  are
           considered, we have information about both horizontal
           and vertical motion,  and we get a very good picture of
           the kind of dispersion which will occur.
           The map in Figure 10-18 shows the average  annual after-
           noon mixing heights and the corresponding  annual wind
           speed averages for some of the major  cities in  the  country.
                        10-24

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        MAXIMUM MxNGT
WIND SPEED AT 1000 ft.   11 mph
WIND SPEED AT 500 ft.  - 10 mph
   AVERAGE WIND SPEED
>  THROUGH MAXIMUM
   MIXING HEIGHT =
       9 mph
SURFACE WIND SPEED - 6 mph
                         Figure 10-17
            You can see that for  Phoenix there is an average annual
            afternoon mixing height of about 2400 meters, while for
            Boston the average is about 1000 meters.  The average
            wind speed through this mixing depth is about 6 meters/
            second, or 13 mph, in Phoenix, while it is 8 meters/
            second, or about 18 mph over Boston.  You can convert the
            rest of these figures to  feet of mixing height and wind
            speed in mph by using the approximte conversion formulas
            and the table given in Figure 10-18.  You will find that
            in meteorology, as in many of the sciences, both metric
            and the more familiar British units of measurements are
            used.  It will help you to become familiar with both of
            these, and to learn a few of the simple rules for
            conversion.
                           10-25

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  AVERAGE MEAN AFTERNOON MIXING HEIGHTS AND  WIND SPEEDS
  AVERAGED THROUGH MIXING LAYER FOR SOME MAJOR U.S. CITIES
         • Portland
           »1200 meters
              m. sec-'
                               Minneapolis •
                                A 1200 meters
                                A 8 m. sec-'
                                                     • Pittsburgh
                                                       A!400 meters
                                                        A 7 «i. sec-1
Denver
*2600 meters
    m. sec''
                                   St. Louis •
                                    »1400 meters
                                         sec-'
                               Charleston
                                A1600 meters
                                 A 6 m. sec''
               • Phoenix
                 A2400 meters
                  A 6 m. sec-'
                         Atlanta •
                             meters
                          A 6 m. sec'
                                        New Orleans
                                         A! 100 meters
                                          A 6 m. sec"1
Los Angeles
»1000 meters
  A5 m. sec-1
                                             Boston
                                             »1000 meters
                                              «B m. sec-1
                  Mean afternoon mixing height, annual
                  average to  convert:  1 meter =
                  approximately  3.3 feet

                  Mean annual wind  speed averaged
                through the  afternoon mixing
                layer to convert:  1  m. sec-'  =
                approximately 2.2  mph
    EQUIVALENT UNITS OF MEASURE USED IN  METEOROLOGY
 LENGTH,
   DISTANCE
            1 meter


            0.305 meter

            0.914 meter
                                                39.37 inches

                                                1.094 yards

                                                1 foot
                                                1 yard
VELOCITY
 (WIND SPEED)
           1 meter per second
           (m.sec-1 or m/sec)
                                                 =  2.2. miles per hour
                                                    (mi. hr-.-l or mi/hr)
TEMPERATURE
           0°centigrade              =  32° Fahrenheit

           ( freezing point of water)

           100°centigrade            - 212° Fahrenheit

           (boiling point of water)

           to convert C = (5/9)(F-32)  F=(9/5) (O32)
PRESSURE
(BAROMETRIC PRESSURE)
           1 millibar

           1. inch mercury
                                                       .0295 inches mercury
                                                       33.9 millibar^
                                    1013.25 mb.Hg.   =    29.9 in.Hg.
                                      (pressure at sea level)

                             Figure 10-18

                                 10-26

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                     The information given on the map in Figure 10-18 does not
                     tell the whole story about dispersion capacity over these
                     cities, since these are annual averages.  However, by
                     studying data of this sort, about vertical and horizontal
                     movement and especially by looking at patterns of daily
                     and seasonal variation and the implications for disper-
                     sion of pollutants, meteorologists have identified some
                     areas of the country where we should recommend against
                     extensive urban development.   These areas, where weather
                     conditions simply do not favor the dispersion of pollu-
                     tants,  include Oregon and central California, the great
                     basin in the Rocky Mountains, northern Minnesota, and
                     the area around and including West Virginia.
                     We have examined in some detail the two meteorological
                     factors that are of primary concern in air pollution
                     dispersion.   Let us look briefly at a few other factors
                     that can be  important in local or specific situations.
Solar Radiation, Precipitation, and Humidity
                     10.7.   Solar  radiation is  important  in the  formation of
                     photochemical oxidants,  since it  plays a vital  role  in the
                     interaction of nitrogen oxides and hydrocarbons emitted
                     from automobiles and some industrial plants.  Sunshine
                     becomes a meteorologically important factor, especially
                     in urban areas on the west coast and in the Rocky Moun-
                     tain area, where there are a great many days each year
                     with clear skies.  Precipitation and humidity can also
                     play an important role, affecting both the dispersion and
                     formation of pollutants.  Precipitation acts as a natural
                     cleansing process, washing particles out of the air.
                     In this sense, precipitation is advantageous, but when
                     there is rain, fog. °r high humidity in  the air, there is
                     also the potential for the conversion of some gaseous
                     pollutants into more potent forms.  One prime example
                                     10-27

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Topography
                     is the conversion of sulfur dioxide into sulfuric acid,
                     which acts to corrode metals and to damage building
                     materials.  The acidity of rain in many urbanized areas
                     has increased significantly in recent years as a result
                     of absorption of air pollutants.
                     10.8.  Topography affects the meteorological factors,
                     and thus, affects the dispersion of pollutants.
                     Local air pollution problems are often related to the
                     effect that topography has on the ability of the atmos-
                     phere to mix pollutants.  Figure 10-19 illustrates
                     some of these problems.  Los Angeles and other coastal
                     areas are plagued by a combination of land and sea breezes
                     and encircling mountain ranges, together with a low
                     mixing height and transport wind speed which act to
                     trap pollutants and cause their accumulation.  Emissions
                     from sources located in mountain valleys or river basins
                     will be trapped by topographical features, especially
                     at night or in the early morning.  Even minor features
                     of the landscape, such as hills, small bodies of water,
                     or a parking lot, can modify the microscale wind flow •:
                     and turbulence, significantly affecting pollutant dis-
                     persion.  So, we can add topography to our list of fac-
                     tors affecting the formation and dispersion of pollutants.
Sky Condition
                     10.9.  Sky condition is another reportable meteorological
                     element that can help make the total visible emission
                     observation process more complete and credible.  Clouds
                     and obscuring phenomena like haze, smoke, or rain de-
                     finitely affect the contrast between the plume and back-
                     ground as does the elevation of the sun and the location
                     of the observer with respect to the plume.
                                    10-28

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  A SEA BREEZE WILL PREVAIL ALONG A LAKE OR SEACOAST DURING THE DAY.
  A LAND BREEZE IS MORE COMMON AT NIGHT. THIS CYCLE, TOO, CAN CAUSE
  POLLUTANT CONCENTRATIONS TO RECUR IN URBAN AREAS
  WINDS WILL TEND TO FLOW OUT OF A VALLEY IN THE DAYTIME, AND DOWN
INTO THE VALLEY AT MIGHT, SOMETIMES CAUSING A  'RECYCLING' OF POLLUTANTS
               Day                                 Night

    UNEVEN TERRAIN WILL CAUSL MECHANICAL TURBULENCE IN THE WIND
  MINOR FEATURES, SUCH AS PARKING LOTS, BUILDINGS, OR VEGETATION, CAN
  AFFECT DISPERSION Of- POLLUTANTS
                                                   ^..---.	-r~
                                                •*\ .-"*""'*  ^"C— ' *""
                                                         -\-
                                                         .J
   Figure 10-19  Topography affects weather circulation and dispersion of
               n.j] Tula iits.
                               10-29

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                                                   i—^"    "'iV ' '4-f?°^  -^^"^'v^i'SLJ
                                                           /     _^f  * •  •"•*    J  *^'v^***''^ *>?i6 iSS**'
                                                   &<^^:^^^«
SURFACE WEATHER MAP
AND STATION WEATHER
  AT 1:00 A.M.E.S T
                            (SURFACE WEATHER  MAP
                              AND STATION WEATHER
                                   AT 1:00 A. M., E. S. T.
  Wmd speed  '2/1     SPECIMEN     J
lo 25 miles per K  gT^TinM WnHlTT  /I
houri          I \
  Direction
ifrom the
west I
 Temperature in !
degrees Fahrenheit (^,

 Total a.-r.ount of j   \
clouds  tSky com- K  N,
pletety covered i I  X  \

 Visibility  I */
miles I

 Present weather
(Continuous s//g/if
mow jn Hakes }

 Oewpomt in de-
grees Fahrenheit

 Cloud type (Low
fractostratus and/or
fractocamalus ',

 Height of cloud
base 1300 to 599
feet-t
                                                               Ooudtype  iM/d-
                                                             e/y« a/focu/nu/uj )
                                                               B*rom«tnc  pre»-
                                                             IUTC at MO level Ini-
                                                             tial 9 01 10 oroittad
                                                             (10247 millibar* I
                                                               Amount  of  baro-
                                                             metric change in
                                                             past 3 hour* I In
                                                             tenths of millibars )
                                                               Barometric  tend-
                                                             ency in past 3 hour*
                                                               ismo:)
                                                               Siqn thowing
                                                             whether pressure is
                                                             higher or lower than
                                                             3 houii ago
                                                               Tim* pivcipiUtion
                                                             began 01 ended (fie-
                                                             gan 3lo4 hours ago \
                                                               Weather in  put  6
                                                             hours • t Rain I
                                                               Amount of precipi-
                                                             tation in last 6 hour*
                                        Abridged fiom W M O. Code
                                          Figure  10-20.
                                           10-30

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The National Weather Service has very explicit rules for
determining sky condition, most of which are too technical
to be discussed in detail here.  Usually most air pollution
inspectors are only required to specify the total cloud
cover according to one of four categories, i.e. clear,
scattered, broken, or overcast, depending on the number
of tenths of the entire sky covered by cloud layers.
Inspectors/smoke readers should also be able to determine
total cloud cover at a given station on a national
weather map such as in Figure 10-20.
A complete evaluation of sky condition includes the
type of clouds or obscuring phenomena present, their
stratification, amount, opacity, direction of movement,
height of bases and the effect on vertical  visibility
of surface-based obscuring phenomena.  Much of this in-
formation can also be gleaned from the plotted station
data in Figure 10-20.   However, this detail is not re-
quired on smoke reading forms.
A few definitions are in order, taken from the GPO Pub-
lications:  "Manual of Surface Observations (WBAN),"
 Circular N, 7th Ed. (Rev.) 1966 with changes to May
1969 (now out of print) and; Federal Meteorological
Handbook No. 1,  "Surface Observations," April, 1970.
     1.  Sky Cover.  A term used to denote the amount
         (to the nearest tenth) of the sky which is:
         (a)   Covered but not necessarily hidden
               by clouds and/or obscuring phenomena
               aloft
         (b)   Hidden by surface-bases obscuring
               phenomena,
               or
         (c)   Covered or hidden by a combination of
               a or b.

                10-31

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2.  Total Amount of Sky Cover.  The amount of tenths
    of the entire sky that is covered, but not neces-
    sarily hidden, by all layers present.  This amount
    cannot be greater than 1.0 (10/10).
3.  Horizon.  The actual lower boundary  (local horizon)
    of the observed sky or the upper outline of terres-
    trial objects including nearby natural obstructions.
    It is the distant line along which the earth, or the
    water surface at sea, and the sky appear to meet.
    The local horizon is based on the best practical
    point of observation near the earth's surface and
    selected to minimize obstruction by  nearby buildings,
    towers, etc.
4.  Transparent Sky Cover.  Those portions of cloud
    layers or obscurations which do not  hide the sky.
    Blue sky or higher clouds can be discerned through
    these portions during daylight, and  the moon and
    brighter stars may be discerned at night.
5.  Opaque Sky Cover.  Those portions of cloud layers
    or obscurations which hide the sky and/or higher
    clouds.  Translucent sky cover that  hides the sun
    and moon (not stars) may be dimly visible will be
    considered as opaque.
6.  Sky Cover Amounts.  Sky cover amounts are evaluated:
    (a)  In terms of the entire sky area above the local
         (apparent), rather than celestial horizon.
    (b)  In tenths of the sky covered for aviation ob-
         servations and national weather map plotting.
    (c)  In terms of the amount of sky covered or hidden.
    (d)  With reference to an observer on the earth's
         surface.
The sky cover symbols, together with their meaning,
teletype contraction,  and brief explanation are given
in Table 10-3,  from "Circular N",  referred to above.
To assist you in determining total sky cover from sur-
face weather maps, remember the basic plotting model where:
             10-32

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                                    dd = wind direction

                                    ff = wind speed

                                    TT = surface temperature

                                  T T, = dew point temperature

                                    VV = surface visibility

                                    ww = present weather

                                     N = sky coverage  (total amount)
                   Table 10-3   sky  Cover Symbols
Symbol
 Meaning &
 Contraction
                                             Explanation1
o
0
  -X
 -©
_;®_j
                Clear CLR
                      0.0 total sky cover.  (This  symbol is used
                      alone  -  not in combination with  others.)
             Scattered Layer
              Aloft  SCTD
                      0.1  to 0.5 sky cover at and below level of
                      layer aloft and not classified  as "thin".
             Broken Layer
             Aloft BRKN
                      0.6  to 0.9 sky cover at and below level of
                      layer aloft and not classified as "thin".
             Overcast Layer
               Aloft OVC
                    .  _
                      1.0  (ten tenths) sky cover  at and below level
                      of layer aloft and not classified as "thin".
              Obscuration
            (Surface Layer)
                      All of sky is hidden by a  surface-based layer,
                      i.e., vertical visibility  is  restricted by the
                      layer.
            Partial
          Obscuration
          (Surface Layer)


            THIN
THIM
BRKN

THIN
OVC
                      C.I or more, but not all  of  sky is hidden by
                      surface-based layer, I.e., vertical visibility
                      through the layer is not  completely restricted.
                                  Transparent sky cover comprises  1/2 or more
                                  of the  total sky cover.   Ref.  definition of
                                             sky
                                     10-33

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N
O
(D
O
(B
3
^
J
O
•
<8>
SKY COVERAGE (Total Amount)
No clouds
Less than one-tenth or
one-tenth
Two-tenths or three-tenths
Four-tenths
Five-tenths
Six-tenths
Seven-tenths or eight- tenths
Nine-tenths or overcast
with openings
Completely overcast
Sky obscured
                               The map plotting symbols for N,
                          total amount of sky coverage, are shown
                          in Figure 21 and can easily be converted
                          to the terms clear, scattered, broken,
                          and overcast as previously defined.

                               Observer skill in determining sky
                          condition can and must be developed with
                          practice and inspectors/smoke readers
                          should make it a habit to evaluate sky
                          cover and effects of obscuring phenomena
                          whenever they are outdoors.  For example,
                          if the circle represents the horizon in
                          the figure below, what is your initial
                          estimate of the sky cover?
                          The correct answer is 5/10 or scattered
                          cloud cover.  Remember, 6/10 of the sky,
                          rounded to the nearest tenth, must be
                          covered with clouds to be termed broken.
Figure 10-21
                    (a)   Determine amounts to the nearest tenth,

                          i.e., if amount present is judged to be

                          zero rather than one tenth, it will be

                          reported as clear (  J .


                    (b)   The symbol   fM    is used in combina-

                          tion with other lower overcast symbols
                        10-34

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      in Col.  3 only when such lower over-
      case layers are classified as thin,
      i.e.,  reported as — f\ J .
(c)    Note that when more than 9/10 of the
      sky, but not all of the sky,  is hidden
      by obscuring phenomena, and:
      (1)   When the sky overhead is obscured,
           report the condition as  an obscura-
           tion "X".
      (2)   When it is not so  obscured, e.g., a
           homogeneous layer, report the condi-
           tion as partial  obscuration,  "—X".
      (3)   Report the direction of  discontinui-
           ties or breaks,  as remarks, e.g., THIN
           FOG NW, or BREAK IN F TO NW.
   10-35

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CHAPTER XI.
LEGAL ASPECTS OF
VISIBLE EMISSIONS

History and Test Cases
                  11.1. Law may be divided into two categories - common
                  law and statute law.
                  11.2. Early air pollution laws fell under the category
                  of prohibiting smoke as a common nuisance or a public
                  nuisance.  Under these common law nuisance regulations
                  it had to be proven in each individual case that the
                  smoke was injurious or offensive to the senses.  .In the
                  case of a public nuisance, it had to be proven that a
                  large number of persons were affected.
                  11.3.  In modern times, smoke and air pollution came to
                  be regarded as an absolute nuisance (a nuisance per se)
                  and a state could pass a statute that declared the emission
                  of dense black smoke to be illegal.  Injury did not have
                  to be proven in each case.
                  11.4.  The State may grant to a city, county, or other
                  local government the power to pass ordinances regulating
                  air pollution.  The State can later cancel the powers
                  which they granted earlier.  The Federal government can
                  also regulate air pollution in certain instances.
                  11.5.  This power to regulate air pollution is given
                  to the States by the Tenth Amendment of the Constitution,
                  which states:  "The powers not delegated to the United
                  States by the Constitution nor prohibited by it to the
                  States are reserved to the States respectively, or to
                  the people."
                                  11-1

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 11.6.  The only constitutional limitation to how far the
 State's air pollution control law can go is in the Four-.
 teenth Amendment to the Constitution: "...nor shall any
 State deprive any person of life, liberty or property,
 without due process of law, nor deny to any person with-
 in its jurisdiction the equal protection of the laws."
 Most of the air pollution cases that are appealed test
 the constitutionality of the control ordinance by means
 of the "due process" clause or the "equal protection"
 clause.
 11.7.  Once black smoke had been declared illegal, laws
 were needed to limit the emission by setting maximum
 permissible pollution standards, or regulating the use
 and operation of equipment and fuels.             ./
 11.8.  Examples of maximum permissible emission standards
 are the Ringelmann Standard and the Equivalent Opacity
 Standard.
 11.9..  In 1910 the Ringelmann Chart was first recognized
 legally in the United States b.y its inclusion in a smoke
 ordinance for Boston passed by the Massachusetts
 Legislature.
 11.10.  The constitutionality of the Los Angeles County
 rule that provides standards for reading of densities
 and opacities of visible emission (L.A. County Rule 50 or
 Section 24242 of the California Health, and Safety Code)_
 has been tested twice, in 1951 and in 1955.  In both of
 these cases its constitutionality was upheld b.y the Los
 Angeles Superior Court.   In 1955 an appeal of the
•Superior Court's decision to the United States Supreme
 Court was dismissed by the Supreme Court.
 11.11.  When first adopted, Section 24242 stated:  "A
 person shall not discharge into the atmosphere from any
 single source of emission whatsoever any air contaminant
               11-2

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for a period or periods aggregating more  than  three
minutes in any one hour which is
     (a)   As dark or darker in shade as  that  desig-
           nated as No. 2 on the Ringelmann Chart  as
           published by the United States Bureau of
           Mines, or
     (b)   Of such opacity as to obscure  an observer's
           view to a degree equal to or greater than
           does smoke described in subsection  (a)_  of  this
           section."
11.12.   The 1951 case, People Versus International
Steel Corporation, dealt with subsection  (a) of Rule  50.
The 19-51 Supreme Court dismissal directly concerned sec-
tion (b.)_ and involved four separate cases of smog
     (1)_  People Versus Plywood Manufacturers  of
          California
     (2),  People Versus Shell Oil Company
     (.3)  People Versus Union Oil Company
     (4)_  People Versus Southern California Edison
          Company
Other cases approving the use of the Ringelmann Chart
include:  Board of Health of Weehawken Township Versus
New York Central Railroad (New Jersey, 1950)..,  and
Penn-Dixie Cement Corp. Versus City of Kingsport
(Tennessee, 19.49.)..
1.1.13.   The California appeal cases established
     (a).   That the Code is constitutional.
     (b)_   That it is permissible for a
           statute to adopt, for a description
           of a prohibited act,- a publication
           of the United States Bureau of Mines.
     (c).   That inspectors trained in the use.
           of the Ringelmann Chart are experts.
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                               They may testify as expert witnesses con-
                               cerning the Ringelmann Number of a particular
                               smoke emission without having had a chart
                               in their possession while observing the plumes.
                         (d)   That the fact that the ordinary person is un-
                               certain whether a smoke plume is as dark as
                               Ringelmann No. 2 or whether its opacity equals
                               that of smoke matching Ringelmann No. 2 is
                               no reason for the unconstitutionality of the
                               Rule.
                         (e)   That the drawing of a line between permission
                               and prohibition (Ringelmann No. 2) is a
                               matter of legislative discretion that will
                               not be reversed by the Courts unless abused.
                         Of)..   That if the plume, fairly viewed from any
                               position, exceeds the regulation of Ringelmann
                               shade, the smoke is in violation no matter how
                               light the color may look to someone situated at
                               another vantage point.
Equivalent Opacity and Smoke Emissions Law
                    11.14.  Some requirements for a good air pollution law
                    are:
                         (a).   It must have the power to reduce
                               contaminat ion.
                         (bX   It must be enforceable.   It must
                               be capable of being enforced uni-
                               formly and it should not be expen-
                               sive to enforce.
                         (c)   It must be reasonable.
                         (d).   It must be clear and precise
                               so that people can understand
                               it and avoid breaking it.
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     (e)   It is not necessary to prove that
           the owner of the stack had criminal
           intent in violating the ordinance,
           just the fact that his smoke is
           blacker than the allowed Ringelmann
           No. is sufficient.
     (f).   Any classification of sources it
           establishes must be reasonable.
           For example, an industry operates
           its stack for profit while a home-
           owner does not; therefore, different
           emission standards can be required
           of industrial and domestic chimneys.
11.15.   As a practical matter, judges will weigh the
equities in a case to determine which of the two
parties will sustain the most injury.  They would not
put a large company out of business, but could require
them to pay a fine or install a control device.
11.16.   Smoke emissions and equivalent opacity regu-
lations may restrict the shade of smoke to be no
darker than a specified Ringelmann Number or a particu-
lar percent opacity, depending upon the source and the
conditions.
11.17.   The different sources regulated may be listed
as fuel burning equipment, internal combustion engines,
open fires, incinerators, railroad locomotives, and
steamships.  The restricted sources may also be described
as stacks or vents or as any single source of emissions
whatsoever.
11.18.   Different restrictions may apply to incinerators
and domestic installations.
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                    11.19.  Limitations may be set allowing smoke of a
                    darker shade for several minutes of every hour during
                    periods when a new fire is being built.
                    11.20.  Exceptions may be granted for fires used in
                    training firemen or on farms.  There may also be
                    exceptions for industrial accidents which, cause black
                    smoke or for special processes.
                    11.21.  Codes may exclude plumes of uncomhined water from
                    the restrictions.
Local Regulations
                    11.22.  The air pollution inspector must know and
                    understand the visible emissions regulations that he
                    will be enforcing.
How To Be An Expert Witness-
                    (.1)  Under ordinary circumstances the average
                         citizen cannot testify as to his opinions or
                         conclusions, but the expert witness can.  The
                         opinion of the expert witness helps the judge
                         make his decision.
                    (.2),  It is preferable to subpoena a
                         witness, even a smoke inspector, to
                         appear in court rather than to have
                         him appear voluntarily.  When the
                         witness is subpoenaed, it demonstrates
                         that he is not appearing in court just
                         because he has a prejudiced opinion for or
                         against one of the parties in the case.
                    (3),  Before appearing in court, prepare your
                         materials and refresh, your memory.   An attorney
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     spends 2 to 10 hours in preparation for
     every hour in court.  An expert witness
     should spend a comparable amount of time in
     reviewing his observations before he testifies.
(4)  As an expert witness the air pollution officer
     should not have to read his testimony.  How-
     ever he has a right to refer to his records
     and notes to refresh his memory.
(5).  Since the case may not appear in court until
     months after the violation occurred, the
     officer should complete his report fully
     at the time of violation.
(.6)  If you take a picture of a plume, you
     should know what operation or process is
     going on in the plant at the time of the
     picture.  Record the time, weather, film type,
     exposure setting, lens type, and distance from
     the plume.
(.7).  Before having any telephone conversations
     with a plant operator, it is desirable to meet
     the man so that you can later identify hi's
     voice on the phone.
(8).  Investigate every case thoroughly.  Do not
     become overconfident after you have appeared
     in court several times.
(_9-X  Behavior on the witness stand:
     (aX   Dress and act like an expert.
     (bX   Be responsive to the question that is
           asked you.  Do not volunteer information
           about some unrelated topic or question.
     (c)   Take a second to frame your answer before
           giving it.
     (d).   If you hear "objection," quit talking.
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                         (e)    If you make a mistake,  admit it.
                         (f)    If you cannot answer just "yes" or "no"
                               to a question, say so.
                         (g)    Keep calm.   Don't lose your temper.
                         (h)    Don't try to second guess your attorney.
                   (10)   You will be directly examined by your attorney
                         and cross-examined by the opposing attorney.
                         There can then be a redirect examination and
                         a recross examination.   You can also be recalled
                         at a later time to clear up your testimony.
Suggested Additional Reading
                    Field Operations and Enforcement Manual for Air
                    Pollution Control APTD-1100, U. S. Environmental
                    Protection Agency, Research Triangle Park, NC  27711
                    1972, available from National Technical Information
                    Service, Springfield, VA 22151.
                    Environment Reporter, The Bureau of National Affairs,
                    Inc., Washington, D.C.
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CHAPTER XII,
OBSERVATION REPORTS FOR VIOLATIONS
                    12.1.  The purpose of making a visual observation of the
                    degree of blackness or whiteness of a plume is to deter-
                    mine if the source is in compliance with regulations.
                    12.2.  To provide a sufficient basis for court prose-
                    cution, the inspector must gather evidence essential for
                    a prima facie case —  that is, a case which unless
                    contradicted adds up to a violation of the law.
                    12.3.  Each and all of the elements of the violation
                    must be proven or else there is no case to take to
                    court.  For instance, if the regulations states:
                    "A person, owner, agent, operator, firm or
                    corporation shall not discharge into the atmos-
                    phere from any single source of emission whatsoever
                    any air contaminant for a period or periods aggre-
                    gating more than three minutes in any one hour which
                    is as dark or darker in shade than that designated
                    as No. 2 on the Ringelmann Chart..."
                    Then all of the following must be proven:
                         (a)   A person, owner, agent, operator, firm
                               or corporation
                         (b)   Discharged
                         (c).   Into the atmosphere
                         (d)   From a single source
                         (e)   A contaminant
                         (f)   Of greater than No. 2 Ringelmann
                         (g).   For more than 3 minutes in 1 hour.
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12.4.  The report and the citation forms when filled
out completely assure the inspector that he has
collected the data essential for supporting a prose-
cution of a violation.
12.5.  The written report is not in itself the evidence
that is used to prove a case in court.  Rather, the
evidence compiled by an inspector consists of his
expert opinion concerning the shade of the emissions
he observed and his testimonial evidence given when
he testifies to the facts surrounding his observations.
12.6.  The written report may not actually appear in the
court proceedings, but the inspector may use it to re-
fresh, his memory.
12.7.  The facts that the inspector should record in his
report of the observation include:
     (a).   The nature and extent of the violation;
     (b)_   The time and location of the violation;
     (c).   The person(s), responsible for the violation;
     (d).   The equipment involved with the violation;
     (e)_   The operational or maintenance factors
           which caused the violation.
12.8.  This information can be filed in two reports-a
smoke observation report and a plant operation report.
The latter would cover information identifying and
describing the equipment that generated the plume and
determining the factor(s)_ that caused the violation.
12.9..  Either of the two reports might contain
information concerning the names and addresses of the
owners of the company and of the operators of the
equipment as well as any remarks these people may have
regarding the equipment.
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12.10.  The smoke observation portion of the report
form should include spaces for the following supplementary
information:
     (a).   Direction or distance of the observer
           from the source;
     (b)   Direction from which the wind was blowing
           and, possibly, the wind speed;
     (c)   Weather conditions during the observation
           describing whether the sky was clear, over-
           cast, scattered, or broken,  and whether it
           was hazy or raining;
     (d)   Date and time during which the observation
           was made;
     (e)   Name and address of the firm where the
           observation was made;
     (_f).   Type of air contaminant;
     (g)_   Description of the source, such as number
           of stacks and their height;
     (h)_   Signature of the inspector.
12.11.  The basic portion of the smoke observation
report should record the visible emissions observed,
showing the continuous time intervals for each density
and opacity and color changes.  The inspector should
note to the -nearest quarter minute the beginning and
ending observation times for each change of density
of color.
12.12.  The total violation time for each hour of
observation should be recorded as well as the total
violation time during the entire period of observation.
12.13.  A photograph of the source can be taken before
or after, but not during the observation.  Photographs
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                    do not always give a true reproduction of plume color.
                    12.14.  Since the accuracy of reading visible emissions
                    is within 7.5% opacity,  it is suggested that a viola-
                    tion notice not be issued to the owner of the equipment
                    unless it is in violation for 1 minute longer than the
                    legal limit and for 1/2 Ringelmann or 10 percent opacity
                    greater than the legal limit.
Special Designations
                    12.15.   In some state, county, and municipal visible
                    emissions regulations, special source categories or
                    specific sources are named.  Some of these include
                         (a).   Fuel-burning equipment
                         (b)_   Combustion equipment
                         (c)   Apartment houses
                         (d>   Office buildings
                         (e)   Schools
                         CfX   Hotels
                         Cg)_   Hospitals
                         (h)..   Process equipment
                         CiX   Motor vehicles
                         (jX   Internal combustion engines
                         (k)_   Diesel motor vehicles
                         (IX   Railroads
                         (m).   Steamships
                         (nX   Incinerators
                         GoX   Open fires
                    12.16.   Emissions from incinerators are often required
                    not to  exceed a Ringelmann No. 1 or an equivalent opacity
                    of 20 percent although the limit for other sources may
                    be No.  2 Ringelmann.   Some state implementation plans
                    have reduced opacity standards to 20% or less.
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                    12.17.  Some ordinances and regulations grant exceptions
                    to the visible emissions regulations.  A few of these are:
                         (a)   Smoke may attain densities as high
                               as No. 3 for an aggregate of 3 minutes
                               in any 15 consecutive minutes when a
                               new fire is being built, a fire box is
                               being cleaned, tubes are being blown,
                               or an equipment breakdown occurs.
                               (Regulations may vary on the time allowed.
                               Other codes include 3 minutes in a
                               30-minute period, 12 minutes in a 24-
                               hour period, etc.)
                         (b).   Smoke from railroad locomotives or steamships
                               may attain values as high as No. 3 Ringelmann
                               for a limited number of minutes during
                               periods ranging from 6 minutes to 8 hours.
                         (,c)_   In some localities, exceptions to visible
                               emission regulations may be granted to
                               certain industrial operations.  Some ex-
                               amples from one State's code are
                               (!)„    Transfer of molten metals;
                               (,2X    Emissions from transfer ladles;
                               (3).    Coke ovens when pushing coke.
                                      after discharge from the ovens;
                               (4).    Water quenching of coke after
                                      discharge from the ovens;
                               (5).    Gray iron cupola furnaces.

Suggested Additional Reading
                    "Guidelines for Evaluation of Visible Emissions" - EPA-
                    340/1-75-00.7, April 1975, National Technical Information
                    Service, Springfield, VA 2216d
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CHAPTER XIII.
EMISSION GENERATOR
                    13.1.  For use in training personnel to read smoke,
                    it is necessary to have a device that will produce
                    both black smoke and white smoke plus an instrument
                    to measure the opaqueness of the smoke that is produced.
                    13.2.  Smoke-generating devices have been built by some
                    air-pollution control agencies for their use.  The
                    principles of operation of all these units are similar.
                    Other agencies have purchased manufactured generators.
Mark II Smoke Generator
Black Smoke
                    13.3.  The Mark I.I Smoke Observers Training Unit,
                    manufactured by Environmental Specialties, is the
                    most widely used smoke generating unit.  It is portable
                    and each unit is custom made; however, the principal
                    features of the Mark II are present in all models.
                    13.4.  When a carbon-containing fuel is burned with
                    insufficient air, a smoky flue gas is produced.  The
                    smoke consists of partially burned carbon particulates
                    suspended in the gas.
                    13.5.  In the smoke generator, black smoke is created
                    by burning toluene with a deficiency of oxygen.  (Diesel
                    fuel is used by some generator operators.)  This fuel
                    is burned in a furnace that consists of a 12-cubic-foot
                    steel combustion chamber lined with refractory bricks.
                    The combustion air entering this chamber is limited.
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White Smoke
Transmissometer
                    The toluene flow into the furnace is controlled by a
                    fine metering valve.  The density of the black smoke
                    is varied by using this valve to adjust the rate of
                    fuel injection through a nozzle into the combustion
                    chamber.  Note:  Toluene has replaced benzene.  Benzene
                    has been placed on the toxic substance list.
                    13.6.  To produce the white smoke, No. 2 fuel oil (the
                    grade usually used for home or commercial heating).
                    is vaporized.  This vapor is then condensed into an
                    aerosol cloud of a white color.  The opacity of this
                    cloud is controlled by adjusting the flow of the No. 2
                    fuel oil.
                    13.7.  In the Mark II, the white aerosol vapor is
                    created by injecting the fuel oil through a hypodermic
                    needle into the manifold carrying the hot exhaust
                    from a small lawnmower-sized gasoline engine.  This
                    engine runs a generator that can provide electric power
                    for the Mark II unit.  Considerable heat is required for
                    vaporizing the fuel oil.  Sufficient heat is provided
                    by operating the generator under an appreciable load.
                    13.8.  In the production of both black and white smoke.,
                    the smoke is diluted with ambient air before it enters
                    the stack.  The degree of dilution is controlled by
                    dampers in the air inlet to the induced draft blower fan.
                    13.9.   The opaqueness of the white or black smoke is
                    measured by a transmissometer located in a 4-foot length
                    of pipe mounted perpendicular to the smoke stack, at a
                    point  6 feet below the top of the stack.  The opaqueness
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measurement from the transmissometer can be read by
the generator operator on a scale divided into Ringelmann
Numbers and equivalent opacity percentages.  The trans-
missometer reading serves as the standard with which the
smoke reader compares his visual observations.
13.10.  The transmissometer for the Mark II is a
simple light source and photocell combination.  The
light source may be a flashlight bulb or automobile
taillight bulb mounted in a silvered reflector that
concentrates the light into a beam that is aimed at
the photocell 4 feet away.  The photocell has a special
sensitivity closely approximating the standard spectral-
luminosity curve for photopic vision.
13.11.  One foot of the path length of the beam is
through the stack of the generator.  In this portion of
the path the intensity of the light is reduced in
proportion to the amount of smoke being produced by
the generator.  This smoke is prevented from entering
the remaining 3 feet of the transmissometer path by
circular smoke stops that reduce the diameter of the
transmissometer pipe.  In addition, these 3 feet of the
transmissometer path are continually flushed with outside
air by two fans, one mounted at each end of the pipe.
13.12.  The combination of smoke stops and ambient air
flushing ensures that there will be no smoke buildup in
the pipe.  As a result, the only obstruction to the light
beam occurs when the beam passes through the 1-foot-
diameter stack.
13.13.  The percent transmission of light that reaches
the photocell is relayed electrically to the operator's
station.  Here, it may be read from the dial of a micro-
ammeter or from a pen trace on a recorder depending
upon which of these devices is supplied with the. generator
unit.
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                    13.14.  The transmissometer system is calibrated from
                    100 percent to zero transmission (zero to #5 Ringelmann
                    and zero to 100 percent equivalent opacity) by inserting
                    several grades of neutral density filters into the light
                    path between the bulb and the photocell and adjusting the
                    microammeter or recorder for the percent of light
                    transmitted.
Conduct of the School
                    13.15.  The smoke reader's training on the smoke genera-
                    tor begins with a familiarization series of black and
                    white smoke densities.  Upon the sound of the horn,
                    the instructor calls out the meter or recorder reading of
                    Ringelmann Number or equivalent opacity.
                    13.16.  After this familiarization period the students
                    go through a practice run of 25 shades of black and 25
                    shades of white smoke.  Each reading is made by the
                    student at the sound of the horn and entered on his
                    training form just as he will do it later when he is
                    reading for qualification.
                    13.17.  Following the practice run the students will
                    begin their qualification runs of 25 white and 25 black
                    shades.
                    13.18.  In between qualification runs the generator
                    operator may conduct short series of familiarization
                    review runs for the benefit of the students.
Other Smoke Generating Equipment
                    13.19.  Los Angeles - 19.62
                         (a)   Black Smoke System
                               The oil burner is a modified mechanical
                               pressure atomizing type.  The. combustion

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      chamber is a 40-cubic-foot-rectangular steel
      box lined with 6 inches of refractory fire
      clay.   The various degrees of incomplete com-
      bustion of the fuel are obtained by adjusting
      the fuel flow.  The smoke from the combustion
      chamber passes along a horizontal duct into a
      cooling chamber and then into the stack.  A
      forced-draft fan discharges ambient dilution
      air into the base of the stack and pushes the
      smoke  up the stack.  This forced draft helps
      to prevent distortion of the plume by the
      wind as the smoke exits  from the stack.   The
      cooling chamber prevents secondary combustion
      from occuring at the base of the stack as the
      combustion products are diluted with air.
(b).   White  Smoke System
      The "white smoke" is created by spraying
      a distillate type of oil into a chamber
      where  it is vaporized by the heat generated
      in an  adjacent heating chamber.  The vapor
      is forced up the stack by a forced draft
      fan that pumps in dilution air.  The vapor
      is condensed into a white cloud of aerosols.
      The operator controls the opacity of the
      plume  by adjusting the rate at which the
      oil is sprayed into the vaporizing chamber
      and the temperature of the heating chamber.
      The heat in this chamber is created by burn-
      ing distillate oil.
(c)_   Opacity and Density Detection System
      Similar to the Mark II,  this system consists
      of a light source and a photoelectric cell
      positioned at opposite ends of a light tube
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                               protruding horizontally from each side of
                               the smoke stack.   The milliammeter,  which
                               registers the light received by the  photo-
                               cell, has a scale arranged so that 100
                               indicates no light and zero indicates free
                               passage of light.  When the operator adjusts
                               the output of the light source to cause a
                               full-scale deflection of the milliammeter,
                               an opacity of zero is read.  If the  light is
                               turned out, no light energy reaches  the cell
                               and the milliammeter reads 100 percent opacity.
Suggested Additional Reading
                    Guidelines for Development of A Quality Assurance
                    Program;  Volume  IX - Visual Determination of Opacity
                    Emissions from Stationary Sources.   EPA Publication
                    EPA-650/4-74-005-1, U.S.  Environmental Protection Agency,
                    Research Triangle Park, NC November, 19.75.

                    Field Operations and Enforcement Manual for Air
                    Pollution Control.  Volume I;  Organization and Basic
                    Procedures,  EPA Publication APTD-1100, U S Environmental
                    Protection Agency, Research Triangle Park, NC, August .19.72.
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CHAPTER XIV.
OPACITY PROBLEMS CAUSED BY
WATER VAPOR
                   14.1.  Introduction.  The ease of monitoring a control
                   area by visual observation has led to the enactment of
                   regulations prohibiting plumes which obscure more than
                   a certain percentage (frequently 40 percent) of an
                   observer's view when he looks through the plume.  One
                   of the problems confronting control officials - using
                   regulations which depend upon the visual determination
                   of equivalent opacity - is that of evaluating plumes
                   containing large quantities of water vapor.  This water1
                   vapor, when it condenses and becomes visible, may make
                   the plume 100 percent opaque even though the quantity of
                   other particulate material is small enough so that the
                   plume, if dry, would not be in violation of the opacity
                   standard.
                   14.2  Is Water Vapor a Pollutant?  The question arises
                   as to whether equivalent opacity regulations should
                   distinguish between those plumes that contain water
                   vapor and those that do not.  Water alone is not
                   injurious to health, and is normally present in any
                   atmosphere, either in the invisible vapor state or
                   in a visible liquid state in the form of fog or clouds.
                   There are objections to water vapor emissions.  Under
                   certain topographical and meteorological conditions, the
                   artifically created water vapor is a contributing
                   factor to a higher frequency of ground fogs.  These
                   can be dangerous if they form in the vicinity of a
                   highway or air field, because they decrease the
                   visibility.  Industrial accidents, also resulting from
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the decreased visibility, may occur within the area of
the emitting factory.  In freezing weather, there is a
possibility of increased ice formation because of the
presence of higher atmospheric relative humidity..  Even
though the emission may be a pure water vapor, there is
the possibility that a combination of the vapor  and
other substances in the air will create a harmful pol-
lutant.  This may occur in the vicinity of large power
plants; when water vapor emitted from cooling towers in
large quantities and sulfur oxides emitted from coal
burning equipment combine in the air to form sulfuric
acid mist, the damage to vegetation and materials may he.
far greater than would be expected if there was no
water vapor emission.
Finally, there may be an objection ha.sed on aesthetic
grounds, to dense plumes regardless of their composi-
tion.  The average citizen cannot distinguish between
a white plume, which is primarily water vapor and
one of the same color containing only a small per-
centage of water.
14.3.  Regulations Governing Wet Plumes.  While
ordinances in some air pollution codes make no distinc-
tion between the visible evaluation of water vapor and
non-water plumes, other air pollution regulations do
make provisions allowing for the emission of "uncombined
water."  Questions can arise about the interpretation
of this term as to whether it means "chemically" un-
combined.  Even though the intent of the regulation may
be to allow for only pure steam plumes,  one may argue
that no water vapor, either naturally or artificially
produced, can condense unless it contains some particle
as a nucleus for the water drop.
One method of "reading" wet plumes is to instruct the
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                    plume inspector to observe these plumes at the point
                    where the condensed water vapor portion of the plume has
                    evaporated.  This prevents the citation of a plume
                    containing a dry opacity below the legal limit, but
                    which because of the accompanying water, exceeds the
                    opacity limit.  This method, however, may protect a
                    polluter because the dry opacity of his plume may
                    exceed the legal limit near the stack.  But at the
                    point where the water evaporates, the plume has dis-
                    persed enough so that its opacity becomes legally
                    acceptable.

Visible Identification of Water Vapor Plumes
                    14.4  Atmospheric Effects on Water Taper,  Water in the
                    gaseous state (as water vapor)  is invisible and is
                    always present in the atmosphere.  One of the measures
                    of the volume of water vapor contained in the atmosphere
                    is relative humidity; the more water vapor contained
                    in a given amount of air, the higher the relative
                    humidity content.  When the air is "saturated"
                    with water vapor, the relative humidity present is
                    100 percent.  Any additional water vapor must condense
                    out into the liquid state and will become visible in
                    the plume.
                    The amount of the water vapor held in the air varies
                    with the temperature of the air.  Warm air can hold
                    more water vapor than cold air.  Consequently, air
                    that is not saturated with water vapor may be cooled
                    until it becomes saturated and the relative humidity
                    then reaches .100 percent.  If this cooling is done at
                    constant pressure, the temperature at which saturation
                    occurs is called the dew point.  If the air is cooled
                    below its dew point, it will be supersaturated and the
                    excess water vapor condenses out into the liquid form
                    of a cloud.
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When wet plumes are initially created in a process, the
gas temperature may be hot enough so that the water is
invisible and is in the vapor form.  If the plume is
cooled sufficiently, either in the stack or in the atmos-
phere, then the plume becomes saturated with water vapor
and condensation takes place.  As the plume is mixed
with the surrounding air, some of the moisture in the
plume is transferred to the ambient air.  This increases
the relative humidity of the ambient air and decreases
the relative humidity of the plume.  When the relative
humidity of the plume reaches 100 percent, the visible
water begins to change by evaporation to an invisible
vapor.  In time the water plume completely disappears.
Under varying atmospheric temperatures or humidity
conditions, two plumes that are emitted from a given
process under identical conditions may form and then
dissipate at different distances from the stack.  In
cold weather a plume may condense, and become visible,
as soon as it leaves the stack.  In hot weather not as
much atmospheric cooling occurs and condensation may
not take place until the effluent has moved some
distance from the stack.  This latter condition results
in a detached plume.
Once formed, the plume disappears more quickly into
the warmer air, which can hold additional water vapor
without becoming saturated.  For example, on two
days with identical temperatures, the plume will persist
for a longer distance on the day with a higher relative
humidity, because the ambient air can hold less water
vapor and cannot absorb additional moisture from the
plume.  Some materials, such as sulfur trioxide (S0_),
are hygroscopic and tend to attract the water vapor
in the air.  These plumes can remain visible to the
observer for longer distances.

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                     Identifying Visible Plumes.   A pure water vapor
                     plume disappears without a trace of dust.  It evaporates
                     quickly,  mixes in all directions, and is characterized
                     by its "wispiness."
                     When plumes are observed under varying atmospheric
                     conditions, those containing large amounts of water
                     vapor may be distinguished by their reactions.  The
                     wet plume may be detached from the stack in warmer
                     weather,  and it will persist for longer distances
                     during periods of high relative humidity.
                     Plumes containing large amounts of sulfur trioxide
                     will become visible as detached plumes when the
                     relative humidity of the ambient air is high because
                     the SCL is hygroscopic.  For the same reason, they
                     will also persist for longer distances than the pure
                     water vapor plumes.

Typical Operations Which Discharge Water Vapor
                     14.5.  Typical Operations Which Discharge Water Vapor.
                       •    Drying operations:
                               (1),  Type of Equipment
                                    (a).  Rotary dryers
                                    (b)_  Spray dryers
                                    (c)  Drum dryers
                                    (d)  Tray and tunnel dryers
                               (2)  Type of Industry
                                    (a)  Powdered milk
                                    (b)  Chemicals
                                    (c)  Pharmaceuticals
                                    (d).  Instant coffee
                                    (e)  Detergents
                                    (f)  Ores
                                    (g)  Paper
                                     14-5

-------
                      •     Combustion operations in which fuels containing
                           hydrogen and hydrocarbons are used
                      •     Air pollution control operations which use
                           water scrubbing to remove solids or pollutant
                           gases:
                              (1)  Typical Equipment
                                   (a).  Venturi scrubbers
                                   (b)_.  Packed towers
                                   (c).  Spray towers
                      •     Cooling operations in which the heat is removed
                           by water evaporation

Methods of Eliminating Visible Wet Plumes
                    14.6.  Methods Eliminating Visible Wet Plumes.
                    Several methods are available to eliminate condensation
                    of the stream plume from a stack:
                         (1)  Dilution of the Plume with Heated Air.
                              Hot air can be mixed with the moist effluent
                              to reduce the dew point and thus prevent the
                              effluent from becoming super-saturated as
                              it enters into the colder air.  (An example
                              of this method will be given later.),
                         (2X  Superheating the Plume.
                              The plume is heated (before emission) to a
                              temperature high enough to disperse the
                              effluent in the atmosphere, before it has
                              cooled to the dew point.
                         (3).  Direct-Contact Condensation with Water.
                              The effluent can be cooled to its dew point
                              by bringing the plume into direct contact
                                    14-6

-------
          with cold water.  There are several ways
          to accomplish this direct-contact cooling:
               (a)  Surface water
               (b)  Cooling tower
               (c)  Air-fin cooler
     (.4)  Indirect-Contact Condensation with a
          Surface Condenser

          If contamination of the cooling water with
          the effluent is a problem, then the plume can
          be cooled by passing it through a tubular
          surface condenser containing circulating water.
          The three methods listed in A-3 above, can
          also be applied to indirect cooling.
     (5)  Combination Processes.
          When the outdoor temperature is low, the
          problem of preventing condensation of the
          plume becomes more difficult because the
          air contains less water vapor before it
          becomes saturated.  Under these conditions
          a combination of methods must be used, e.g.,
          removing some of the moisture by condensation
          and then reheating the plume before dis-
          charging it.
Problems.that may be encountered include:
     (1)  Additional pollutants and excess energy use
          occurs when the plume is superheated or
          diluted with heated air.
     (2)  When the water vapor in the plume is prevented
          from condensing in the atmosphere (by use of
          the direct-contact condenser cooling method)
          certain requirements must be considered:
                14-7

-------
                                   (a)   A large quantity of cooling
                                        water must be available.
                                   (b)   The cooling water will pick up
                                        and convert some of the air
                                        contaminants into water pollutants.
                                   (c)   The cooling water will absorb some
                                        of the heat from the plume.  If
                                        the volume of heat is large enough,
                                        thermal pollution may become a
                                        problem.
                         (3).  When the water vapor contained in a plume is
                              condensed by direct or indirect contact
                              condensation with water there will still be
                              a discharge of water vapor into the atmos-
                              phere .   The condensate will be transferred
                              from the stack, to a cooling tower or the
                              surface of a river or lake, where it may be-
                              come less objectionable to the community.
                         (.4)  The most economical method, on an annual
                              operating cost basis, is direct condensation
                              with natural surface water; however, natural
                              water is not always available.  The only
                              method that minimizes air, water, and thermal
                              pollution (condensation with a surface
                              condenser using an air-fin cooler) is the
                              second most expensive one.  In tall stacks,
                              such as found in power plants, it is nec-
                              essary to heat the effluent gases (when
                              scrubbers are used) to obtain adequate
                              bouancy of the gases in the stack.
                          9
Reading Water Vapor Plumes
                    14.7.   If the condensed water vapor plume is detached,
                    opacity determinations can be made immediately at
                                   14-8

-------
                    the stack exit, i.e., before the water vapor begins
                    to condense.
                    If the water vapor plume is attached to the stack,
                    readings should be made at the point where the water
                    droplets have revaporized completely.   This point may
                    be some distance downwind thus allowing the pollutants
                    to become diluted by mixing with the ambient air.
                    The further downwind this point is, the more dilute
                    will be the pollutants and the lower the opacity read-
                    ings will become, which of course, tends to act in
                    favor of the source.
                    If the inspector has any question about the quantity
                    of pollutants being emitted by a source and is unable
                    to take a reading close to the stack because of the
                    condensed water vapor plume, a source test should be
                    ordered.
                    The best way of handling the problem is to make
                    the visit to the plant when there is a good possibility
                    that the condensed water vapor plume will not be present.
                    Using a psychrometric chart, according to the procedures
                    of Section 14.9. in conjunction with estimates of
                    meteorological and effluent conditions, and a few
                    minutes of computation, the inspector may determine
                    whether or not there is a good possibility that the
                    water vapor in the plume will condense.  This procedure
                    could save the inspector a wasted trip to the plant in
                    question.  An example of the use of the psychrometric
                    chart is given below.

Description of the Psychrometric Chart
                    14.8.  A psychrometric chart is a graphical solution of
                    various temperature and humidity states of air and
                    water vapor mixtures.  Each point on the chart represents

                                   14-9

-------
one unique combination of the following atmospheric
properties:
     (.1)  Dry bulb temperature, which is the
          actual temperature of the gas.
     (2)  Wet bulb temperature, which is the temperature
          indicated by a thermometer that has its bulb
          covered with water and placed in a stream
          of moving air.
     (3X  Relative humidity, which is the ratio of
          the partial pressure to the saturation
          vapor pressure of water, at the same
          temperature.
     (.4X  Humidity ratio, which is the ratio of the
          mass of water vapor present per unit mass
          of dry air.
     C5)_  Specific volume of dry air, which is the
          volume occupied by unit mass of dry air.
If any two of these parameters are known, then the
state point on the psychrometric chart is defined.
The psychrometric chart for normal atmospheric
pressure conditions is shown in Figure 14-1, which
is sufficiently accurate for the estimates involved
in this procedure for most parts of the country.
The curved line along the left side of the chart
represents the 1QO percent relative humidity line, or
the saturation line.   Any state point to the left
of this line, or the path of any process crossing
this line, will normally be accompanied by condensation
of the water vapor resulting in the formation of a
steam plume.  As can be seen from the psychrometric
chart:
     (a)  Toward the lower end of the ambient
          temperature range it takes very little

               14-10

-------
 1450 t
    o

    i

 400 x
              PSYCHROMETRIC CHART

        Barometric Pressure   29.92 Inches of Mercury
350





300




730 •




700

   cr

   <

650 >
   
-------
                              moisture to fully saturate the air,  and thus
                              the possibility of the moisture in the plume
                              condensing is very high, no matter what the
                              stack exit conditions may be;
                         (b)  The possibility of a steam plume being formed
                              is smallest on hot, dry days.
Example of the Use of the Psychrometric Chart
                    14.9.   The psychrometric chart shown in 14.1 may be
                    used to determine if a condensed water vapor plume is
                    to be formed from a specific source if the ambient
                    weather conditions are known.
                    Usually the information given (or estimated), is
                    the ambient temperature and relative humidity, and the
                    effluent gas temperature and moisture content, the
                    latter being defined as the volume percentage of water
                    vapor in the effluent gases.
                    Knowing the moisture content (M.C.), a value for the
                    humidity ratio may be obtained from the following
                    expression:
                    u  .,._  D „.      4354 (M.C.) Grains
                    Humidity Ratio  =  ,    ^—  '~    	 .
                                       1-M.C.  Lb of Dry Air
                    which follows  from the Ideal Gas Law and the defini-
                    tions of humidity ratio and moisture content.
                    The initial state point is given by the effluent gas
                    temperature and the humidity ratio, and the final
                    state point is given by the ambient wet and dry bulb
                    temperatures.
                    Ambient
                    Air Temperature (dry bulb)   = 70°F
                    Wet Bulb Temperature         = 60°F
                    Barometric Pressure          = 29_ 92 inches Hg
                                   14-12

-------
                    Effluent Gas
                    Exhaust Temperature (dry bulb)     = 160 F
                    Moisture Content                   =16.8%
                    Substituting these values into the expression for the
                    humidity ratio gives:
                    ti  -A-*  T, „•    4354 (0.168)
                    Humxdity Ratio =       -
                                   = 880 Grains
                                         Lb. of dry air
                    The state point of the ambient air is at the inter-
                    section of the 70 F dry bulb temperature line and the
                    60 F wet bulb temperature line.  The effluent gas
                    state point is at the intersection of the 880 grains per
                    pound of dry air line and the 160 F dry bulb temperature
                    line.
                    Figure 14.2 shows the two state points plotted on the
                    psychrometric chart.  A line connecting these two
                    state points crosses the saturation curve at about 112°F
                    and 84 F indicating that a condensed water vapor plume
                    is a distinct possibility.  As the plume mixes with
                    the ambient air the water vapor in the plume will
                    begin to condense when the effluent temperature reaches
                    112 F and will begin to revaporize when its temperature
                    is further cooled to 84 F.
Bibliography For Subsection on "Reading Water Vapor Plumes"
                    1.  Buffalo Forge Company.  Fan Engineering.  19.70..
                    2.  California Air Resources Board.  Visible Emission
                        Evaluation Course Manual.   1974.
                    3.  Crocker, B. B., Water Vapor in Effluent Gases:
                        What  to do about Opacity Problems.  Chemical
                        Engineering,  June,  1968.
                                   14-13

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                                                                                                                                       0.12
I
M
*•
                  PSYCHROMETRIC CHART
             Barometric Pressure   29.92 Inches of Mercury
             40  SO  6O  70   80   90  IOO   110   120   130  140  ISO  160  170  180  190  200  2IO  220  230  240  230  26O  270  280  290  300  310  320  330
                                                                    DRY BULB TEMPER  JRE-'F

                                                                                                              Buffalo  Forge Company

                                   Figure 14-2.   PSYCHROMETRIC CHART  (Sea Level  Conditions)

-------
4.  Faires, V. Thermodynamics.  The MacMillan Company,
    New York.  1962.
5.  Kalika, P. W.  How Water Recirculation and Steam
    Plumes Influence Scrubber Design.  Chemical
    Engineering, July 1969.
6.  Lee, J. F. and F. W. Sears.  Thermodynamics.
    Addison-Wesley Publishing Company,  1955.
7.  Reigel, S. A. and C. D. Doyle.  Using the
    Psychrometric Chart.  Pollution Engineering,
    March 1972.
8.  Rohr, F.  W.  Suppressing Scrubber Steam Plume.
    Pollution Engineering, November .19.69.

9.,  From "Guidelines for Evaluation of Visible Emissions"
    EPA^340/l-75-007, April 1975,
                14-15

-------
References
                  Ringelmann, M., "Methods d1Estimation des Fumes
                  Produites par les Foyers Industriels," La Revue
                  Technique, 268 (June 1898).
                  Marks, L. S., "Inadequacy of the Ringelmann Chart,"
                  Mech. Eng., 681 (Sept. 1937).
                  Health and Safety Code, State of California, Chap. 2,
                  Sec. 24242 (19.47)...
                  Yocom, J. E., "Problems in Judging Plume Opacity,"
                  J. Air Poll. Control Assn.. 13, 36-39 (Jan. 1963).
                  Connor, W. D., Hodkinson, J. R. "Optical Properties
                  and Visual Effects of Smoke Stack Plumes," U. S. Dept.
                  of HEW, Public Health Service, Publication 999-AP-30,
                  Cincinnati, 1967, pp. 23-28, 58-59L.
                  Tukey, J. W., et al., "Restoring the Quality of Our
                  Environment" Panel of the President's Science Advisory
                  Committee, the White House, (Nov. 1967), pp. 71-72.
                  Crocker, B. B., "Water Vapor in Effluent Gases:  What
                  to Do about Opacity Problems," Chemical Engineering
                  (July 15, 1968)..
                  Sheehy, J. P., Archinger, W. C., Simon R. A.,
                  "Psychrometric Chart," Handbook of Air Pollution.
                  U. S. Dept. of HEW, Public Health Service, pages
                  11-9-11-14.
                  Citation:  Lloyd A. Fry Company v. Utah Air Conservation
                  Committee, 545 P 2d 495 (Utah, 19-75). APCA Journal,
                  August, 1976, Volume 26, No. 8, pg. 819.
                  Kalika, Peter W. "How Water Recirculation and Steam
                  Plumes Influence Scrubber Design," Chemical Engineering,
                  (July 28, 1969).
                                 14-16

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  STATIONARY SOURCES
                                                                                 S-395
                                                                            121:1579
METHOD  9	VISUAL DETERMINATION  OF THE
  OPACITY  OP  EMISSIONS FROM  STATIONARY
  SOURCES
  Many stationary sources discharge visible
emissions into the atmosphere; these emis-
sions are  usually  In the shape of a plume.
This method Involves  the  determination of
plume opacity by qualified  observers. The
method includes procedures for the  training
and certification of observers, and procedures
to be used In the  field for determination of
plume opacity. The appearance of a plume as
viewed by an observer  depends upon a num-
ber of  variables, some  of which may be con-
trollable and Eome of which may not  be
controllable in the field. Variables which can
be controlled to an extent to which  they no
longer exert  a significant Influence upon
plume appearance Include: Angle of the  ob-
server with respect to the plume: angle of the
observer  with respect  to the sun; point of
observation of  attached and detached steam
plume; and angle  of  the observer with re-
spect to a plume emitted from a rectangular
stack with a large  length to width ratio. The
method Includes specific criteria applicable
to these variables.
  Other variables which may not be  control-
lable In the field are luminescence and color
contrast  bstween  the  plume and the back-
ground against which the plume Is viewed.
These  variables exert an Influence upon  the
appearance  of a plume as viewed by an  ob-
server, and  can affect  the ability of the  ob-
server  to accurately  assign  opacity values
to the  observed plume. Studies of the theory
of plume opacity and field studies have dem-
onstrated that a plume  Is most visible and
presents the greatest apparent opacity when
viewed against a contrasting background. It
follows from this, and is confirmed  by field
trials,  that  the opacity of a plume, viewed
under  conditions where a contrasting back-
ground Is present can be assigned with  the
greatest degree of accuracy. However, the po-
tential for a positive error is also the greatest
when a plume Is viewed under such contrast-
Ing conditions. Under conditions presenting
a less contrasting background, the apparent
opacity of a plume Is less and approaches
zero as the color and luminescence contrast
decrease toward zero. As  a result,- significant
negative bias and  negative errors  can  be
made when a plume  Is  viewed  under less
contrasting  conditions. A  negative bias de-
creases rather than Increases the possibility
that a plant operator will be cited for a vio-
lation of opacity standards due to observer
error.
  Studies have been undertaken to determine
the magnitude of positive errors which can
be made by qualified observers while, read-
ing plumes under contrasting conditions and
using  the  procedures  set  forth  In  this
method. The  results  of  these  studies (field
trials) which  Involve  a  total of 769  sets of
25 readings each are as follows:
  (l).For black plumes (133 sets at a smoke
generator),  100  percent of the sets  were
read with a positive  error1 of less than ".5
percent opacity; 99 percent  were read  with
a positive error of less than 5 percent opacity.
  (2) For white plumes  (170 sets at a smoke
generator, 168 sets at a coal-fired power plant,
298 sets at a sulfuric  acid plant), 99 percent
of the sets were read with a positive error of
less than 7.5 percent opacity; 05 percent were
read with a positive error of less than 6 per-
cent opacity.
  The positive observational error associated
with  an average of twenty-five readings Is
therefore  established.  The accuracy  of  the
method must be taken  into account when
determining  possible violations of  appli-
cable opacity standards.
  'For a set, positive error=average opacity
determined by observers' 25 observations—
average opacity determined from transmls-
someter's 25 recordings.
   1. Principle and applicability.

   1.1  Principle.  The  opacity of emissions
from stationary sources  is determined vis-
ually by a qualified observer.
   1.2  Applicability. This method Is  appli-
cable for the determination  of the opacity
of  emissions from stationary sources pur-
suant to § 60.11 (b) and  for  qualifying ob-
servers for visually determining  opacity of
emissions.
   2. Procedures.  The  observer  qualified In
accordance with paragraph 3  of this method
shall use the following procedures for vis-
ually determining the opacity of  emissions:
  2.1  Position.  The qualified observer shall
stand  at a distance sufficient to  provide a
clear view of the  emissions  with the  sun
oriented In the 140' sector to his back. Con-
sistent with maintaining  the  above require-
ment, the observer shall, as much as possible,
make his observations from a position such
that his line  of  vision  Is  approximately
perpendicular to the  plume  direction,  and
when observing opacity  of emissions  from
rectangular outlets (e.g. roof monitors, open
baghouses,  nonclrcular  stacks),  approxi-
mately  perpendicular  to  the  longer axis of
the outlet. The observer's line  of sight should
not  Include more than one plume at a time
when multiple stacks are Involved, and in
any case  the observer should make his ob-
servations with his  line of sight perpendicu-
lar to the longer axis of such a set 6f multi-
ple stacks (e.g. stub stacks on  baghouses).
  2.2 Field records. The  observer shall re-
cord the name of  the plant,  emission loca-
tion, type  facility,  observer's  name  and
affiliation, and the date on a field data sheet
(Figure 9-1). The  time, estimated distance
to the emission  location,  approximate wind
direction, estimated wind speed, description
of the sky condition (presence and color of
clouds), and plume background  are recorded
on a field data sheet at the time opacity read-
ings are  initiated and completed.
  4-21-78
                 Published by THE BUREAU OF NATIONAL AFFAIRS, INC.. WASHINGTON. D.C. 20037
                                                                                                                                 91

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                121:1580
                                                                                                                          FEDERAL  REGULATIONS
Oi
  2.3  Observations.  Opacity  observations
shall be made at the point of greatest opacity
In that portion of the  plume  where con-
densed water vapor Is not present. The ob-
server  shall not look continuously at the
plume, but Instead shall observe the plume
momentarily at 16-second Intervals.
  2.3.1  Attached steam plumes. When con-
densed  water  vapor  Is present within the
plume as It emerges from the emission out-
let, opacity observations shall be  made be-
yond the point In the plume at which con-
densed water vapor Is no longer visible. The
observer shall record the approximate  dis-
tance from the emission  outlet to the point
In the plume at which the observations are
made.
  2.32  Detached steam plume. When water
vapor In the  plume condenses and becomes
visible at a distinct distance from the emis-
sion outlet, the opacity of emissions should
be evaluated at the emission outlet prior to
the condensation of water vapor and the for-
mation of the steam plume.
  2.4  Recording observations.  Opacity ob-
servations shall be recorded to the nearest 6
percent at 15-second Intervals  on  an ob-
servational record sheet.  (See Figure 9-2 for
an example.)  A minimum of 24 observations
shall be recorded. Each momentary observa-
tion recorded shall be deemed to represent
the average opacity of emissions  for a 15-
secoad period.
 "23  ~Data Reduction. Opacity shall be de-
termined as an average  of 24  consecutive
observations recorded  at 15-sccond Intervals,
Divide the observations recorded on the rec-
ord sheet Into sets  of 24 consecutive obser-
vations. A  set is composed  of any 24 con-
secutive observations. Sets need not be con-
secutive in time and In no  case  shall  two
sets overlap. For each set of 24 observations,
calculate the average by summing the opacity
of the 24 observations and dividing this sum
by 24. If an applicable standard  specifies an
averaging time  requiring more than 24 ob-
servations,  calculate the  average.for all ob-
servations  made during  the specified time
period. Record the average opacity on a record
sheet. (See Figure 9-1  for an example.)
   3. Qualifications and testing.
   3.1  Certification requirements. To receive
 certification as a qualified observer, a can-
 didate must be.tested and demonstrate the
 ability to assign opacity readings in 5 percent
 Increments to 25 different black plumes and
 25 different  white  plumes, with an  error
 not to exceed 15 percent opacity on any one
 reading and an average error  not to exceed
 7.5 percent opacity in each category. Candi-
 dates shall be tested according to  the pro-
 cedures described in paragraph 3.2. Smoke
 generators used pursuant  to  paragraph 3.2
 shall be equipped with a smoke meter which
 meets the requirements of paragraph 3.3.
   The certification shall be valid for a period
 of 6 months, at which time the qualification
 procedure must be repeated by any observer
 In order to retain certification.
   3.2   Certification procedure. The certifica-
 tion test consists of showing the candidate a
 complete run of 50 plumes—25 black plumes
 and 25 white plumes—generated by a smoke
 generator. Plumes within each set of 25 black
 and 25 white runs shall be presented In ran-
 dom order. The candidate  assigns an opacity
 value to each plume and  records his obser-
 vation on a suitable  form. At the  completion
 of each run of 50 readings, the score of  the
 candidate Is determined. If a candidate falls
 to qualify, the complete run of 50 readings
 must be repeated In any  retest. The smoke
 test may be administered  as part of a smoke
 school or training program, and may be pre-

 ceded by training or familiarization runs of
 the smoke generator during which candidates
 are shown black and  white plumes of known
 opacity.
   3.3  Smoke  generator specifications. Any
 smoke ganerator  used for the purposes  of
 paragraph 3.2 shall be equipped with a smoke
 meter  installed to  measure  opacity  across
 the diameter of the  smoke generator stick.
 The smoke meter output shall display  In-
 Etack opacity based upon a pathlength equal
' to the stack exit diameter, on a full 0 to  100
 percent chart recorder  scale. The  smoke
 mster optical design and  performance shall
 meet  the specifications shown in Table 9-1.
The smoke meter shall be calibrated as pre-
scribed  in paragraph 3.3.1 prior to the con-
duct  of each smoke reading  test. At  the
completion of each  test, the zero and span
drift  shall be checked and If  the drift ex-
ceeds ±1 percent opacity, the condition shall
be corrected prior to conducting any subse-
quent test runs. The smoke meter shall be
demonstrated, at the time of installation, to
meet  the specifications listed In Table 9-1.
This  demonstration shall  be repeated fol-
lowing any subsequent repair or replacement
of the photocell or associated electronic cir-
cuitry Including the chart recorder or output
meter, or every  6  months, whichever occurs
first.

    TABLE 9-1	SMOKE METER DESIGN AND
        PERFORMANCE SPECIFICATIONS

Parameter:                Specification
a. Light source	 Incandescent   lamp
                       operated at nominal
                       rated voltage.
b. Spectral  response Photoplc    (daylight
    of  photocell.       spectral response of
                       the human  eye—
                       reference 4.3).
c. Angle of view	 15°   maximum   total
                       angle.
d. Angle  of  projec- 15°   maximum   total
    tion.              angle.
e. Calibration error. ±3%  opacity,  maxi-
                       mum.       <
f. Zero   and   span ±1%   opacity,   30
     drift.             minutes.
g. Response time— £5 seconds.
  3.3.1  Calibration.  The  smoke  meter Is
calibrated after allowing  a minimum of 30
minutes warmup  by alternately  producing
simulated opacity of 0 percent and 100 per-
cent.  When stable response at 0 percent or
100 percent Is noted, the smoke meter  is ad-
justed to produce  an output of 0 percent or
100 percent, as appropriate. This calibration
shall  be repeated until stable 0 percent and
100 percent readings are  produced  without
adjustment. Simulated 0  percent and  100
percent opacity  values may be  produced by
alternately switching the power to the light
source on and off while the smoke generator
Is not producing smoke.
                                                                           Environment Reporter
                                                                                                          [Appendix A]
                                                                                                                                   92

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 g
 2
C
a
5!
n


1
n
G
    COMPANY	

    LOCATION	

    TEST NUMBER,

    DATE	
                   TYPE FACILITY
                   CONTROL DEVICE
                                                         FIGURE 9-1
                                          RECORD OF VISUAL. DETERMINATION. OF OPACITY
                                                                                                                             pf_
                                                                                                HOURS OF OBSERVATION.

                                                                                                OBSERVER	
                  OBSERVER CERTIFICATION DATE_

                  OBSERVER AFFILIATION	

                  POINT OF EMISSIONS
                                                                      O


                                                                      30
                                              O
                                              c
                                              3D
                                              O
                                                                                  HEIGHT  OF  DISCHARGE POINT
 z

 I
 r
3
to

Z
n
i
O
O

to
a
a
x'
    CLOCK TIME

12  OBSERVER LOCATION
      Distance to Discharge


      Direction from Discharge


      Height of Observation Point


    BACKGROUND DESCRIPTION


    WEATHER CONDITIONS
      Wind Direction


      Wind Speed


      Ambient Temperature


    SKY CONDITIONS (clear,
      overcast, % clouds, etc.)


    PLUME DESCRIPTION
      Color


      Distance Visible

     OTHER IHFOOTIOtl
                                   Initial
Final
SUMMARY OF AVERAGE OPACITY
Set
Number










TlmP
Start—End










Opadti
Sum.










"verage










                                                                                           Readings ranged from
                                       to
                        % opacity
                                                                                           The source was/was not In compliance with
                                                                                           the time evaluation was made.
                                                            .at
                                                                                                                                                   to

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       COMPANY 	
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       TEST NUMBER
       DATE 	
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                        FIGURE 9-2  OBSERVATION RECORD
                   PAGE	OF	
OBSERVER 	
TYPE FACILITY 	
POINT OF EMISSIONS
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                                                                                                                      r~
                                                                                                                      30
                                                                                                                                                                   o
                                                                                                                                                                   z
                                                                                                                                                                   V)

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    CHAPTER XVI
   FEDERAL  STANDARDS OF PERFORMANCE FOR
 NEW  STATIONARY  SOURCES OF AIR  POLLUTION
                      A Summary  of  Regulations
                                        Linda S. Chaput
                            U. S. Environmental  Protection Agency
In order to make the information in the Federal Register more easily ac-
cessible, a summary has been prepared of Federal standards of perfor-
mance for new stationary sources of air pollution. The standards of perfor-
mance promulgated by the Environmental Protection Agency in the peri-
od from December 1971 through June 1976 are presented in tabular form.
    Ms. Chaput is in the Standards
  Development Branch, Office of Air
  Quality Planning and Standards, U.
  S. Environmental Protection Agen-
  cy,  Research  Triangle  Park,  NC
  27711.
Anyone who must use the Federal Reg-
ister frequently to refer to regulations
published by Federal agencies is well
aware of the problems of sifting through
the many pages to extract the "meat" of
a regulation. Although regulatory lan-
guage is necessary to make the intent of
a regulation clear, a more concise refer-
ence to go to when looking up a partic-
ular standard would be helpful. With
this in mind, the  following table was
developed to assist those who work with
Federal standards of performance for
new stationary sources of air pollu-
tion.
  The table lists the standards of per-
formance which  the Environmental
Protection Agency (EPA) has promul-
gated since December 1971. It includes
the categories of stationary sources and
the  affected  facilities  to which  the
standards apply; the pollutants which
                         Reprinted from APCA JOURNAL, Vol. 26, No. 11, November 1976

                                               16-1

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                  Standards  of  Performance - 40 CFR  Part 60.
Source Affected
category facility
Subpart D:
Steam generators Coal fired boilers
(>250 million Btu/hr)

Promulgated
12/23/71 (36 FR 24876)

Revised
7/26/72 (37 FR 14877)
6/14/74 (39 FR 20790) oil fired boilers
1 /1 6/75 (40 FR 2803)
10/6/75 (40 FR 46250)

Gas fired boilers


Subpart E:
Incinerators Incinerators
(>50 tons/day)
Pollutant

Particulate
Opacity
S02
NOX
(except lignite
and coal
refuse)

Particulate
Opacity
SO2
NOX
Particulate
Opacity
NOX

Particulate

Emission level

0.10lb/106Btu
20%
1.2 lb/10<*Btu
0.70 lb/1Q6Btu




0.10lb/106Btu
20%; 40% 2min/hr
0.80lb/106Btu
0.30lb/106Btu
0.10 lb/106Btu
20%
0.20lb/106Btu

0.08 gr / dscf corrected
to 12% CO2
Monitoring
requirement

No requirement
Continuous
Continuous
Continuous




No requirement
Continuous
Continuous
Continuous
No requirement
No requirement
Continuous

No requirement

   Promulgated
   12/23/71 (36 FR 24876)

   Revised
   6/14/74 (39 FR 20790)
Subpart F:
Portland cement plants

Promulgated
12/23/71 (36 FR 24876)
Revised
6/14/74 (39 FR 20790)
1 1/1 2/74 (39 FR 39874)
10/6/75 (40 FR 46250)
Subpart G:
Nitric acid plants


Kiln


Clinker cooler

Fugitive
Emission points

Process equipment


Perticulate
Opacity

Particulate
Opacity
Opacity

Opacity
NOX

0.30 Ib/ton
20%

0.10 Ib/ton
10%
10%

10%
3.0 Ib/ton

No requirement
No requirement

No requirement
No requirement
No requirement

No requirement
Continuous
  Promulgated
  12/23/71 (36 FR 24876)

  Revised
  5/23/73 (38 FR 13562)
  6/14/74 (39 FR 20790)
  10/6/75 (40 FR 46250)
  Subpart H:

  Sulfuric acid plants

  Promulgated
  12/23/71 (36 FR 24876)

  Revised
  5/23/73 (38 FR 13562)
  6/14/74 (39 FR 20790)
  10/6/75 (40 FR 46250)
Process equipment
SO2
Acid mist
Opacity
4.0 Ib/ton
0.15 Ib/ton
10%
Continuous
No requirement
No requirement
1056
                    16-2
               Journal of the Air Pollution Control Association

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           Source
          category
        Affected
         facility
    Pollutant
                         Emission level
                            Monitoring
                            requirement
   Subpart I:

   Asphalt concrete plants

   Promulgated
   3/8/74 (39 FR 9308)

   Revised
   10/6/75 (40 FR 46250)
Dryers; screening and         Particulate         0.04 gr/dscf
weighing systems;                              (90 mg/dscm)
storage, transfer, and         Opacity           20%
loading systems; and
dust handling equipment
                                            No requirement

                                            No requirement
Subpart J:
Petroleum refineries

Promulgated
3/8/74 (39 FR 9308)

Revised
10/6/75 (40 FR 46250)

Catalytic cracker



Fuel gas
combination


Particulate
Opacity
CO

SO2



1.0 lb/1000 Ib
30% (3 min. exemption)
0.05%

0.1 gr H2S/dscf
(230 mg/dscm)


No requirement
Continuous
Continuous

Continuous


  Subpart K:

  Storage vessels for
  petroleum liquids

  Promulgated
  3/8/74 (39 FR 9308)

  Revised
  4/17/74 (39 FR 13776)
  6/14/74 (39 FR 20790)
  Subpart L:

  Secondary lead
  smelters

  Promulgated
  3/8/74 (39 FR 9308)

  Reviced
  4/17/74(39FR13776)
  10/6/75 (40 FR 46250)
Storage tanks
>40,000 gal. capacity
Hydrocarbons
For vapor pressure
78-570 mm Hg, equip
with floating roof,
vapor recovery system,
or equivalent; for
vapor pressure >570
mm Hg, equip with
vapor recovery system
or equivalent
No requirement
Reverberatory and
blast furnaces
Pot furnaces
 Particulate

 Opacity

 Opacity
0.022 gr/dscf
(50 mg/dscm)
20%

10%
No requirement

No requirement

No requirement
Subpart M:
Secondary brass and
bronze plants

Promulgated
3/8/74 (39 FR 9308)

Revised
10/6/75 (40 FR 46250)
Subpart N:
Iron and steel plants

Promulgated
3/8/74 (39 FR 9308)

Reverberatory
furnace


Blast and
electric furnaces



Basic oxygen
process furnace



Particulate 0.022 gr/dscf
(50 mg/dscm)
Opacity 20%

Opacity 10%




Paniculate 0.022 gr/dscf
(50 mg/dscm)



No requirement

No requirement

No requirement




No requirement



November 1976     Volume 26, No. 11
                                                             16-3
                                                                                    1057

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           Source
           category
        Affected
         facility
    Pollutant
                        Emission level
                             Monitoring
                            requirement
   Subpart O:

   Sewage treatment
   plants

   Promulgated
   3/8/74 (39 FR 9308)

   Revised
   4/17/74(39FR13776)
   5/3/74 (39 FR 15396)
   10/6/75 (40 FR 46250)
Sludge incinerators
Particulate

Opacity
1.30lb/ton

20%
Mass or volume
of sludge
No requirement
   Subpart P:

   Primary copper
   smelters

   Promulgated
   1/15/76(41 FR2331)

   Revised
   2/26/76 (41 FR 8346)
Dryer
Roaster, smelting
furnace,* copper
converter

•Reverberatory furnaces
that process high-
impurity feed materials
are exempt from
SC>2 standard
Particulate

Opacity

S02
Opacity
0.022 gr/dscf
(50 mg/dscm)
20%

0.065%
20%
No requirement

Continuous

Continuous
No requirement
Subpart Q:
Primary zinc
smelters
Promulgated
1/15/76(41 FR 2331)
Subpart R.:
Primary lead
smelters
Promulgated
1/15/76(41 FR2331)
Subpart S:
Primary aluminum
reduction plants
Promulgated
1/26/76(41 FR3825)


Sintering machine
Roaster

Blast or reverberatory
furnace, sintering
machine discharge end
Sintering machine,
electric smelting
furnace, converter

Potroom group
(a) Soderberg
plant
(b) Prebake
plant
Anode bake plants

Particulate
Opacity
SO2
Opacity

Particulate
Opacity
SO2
Opacity

(a) Total
fluorides
Opacity
(b) Total
fluorides
Opacity
Total fluorides
Opacity

0.022 gr/dscf
(50 mg/dscm)
20%
0.065%
20%

0.022 gr/dscf
(50 mg/dscm)
20%
0.065%
20%

2.0 Ib/ton
10%
1.9 Ib/ton
10%
0.1 Ib/ton
20%

No requirement
Continuous
Continuous
No requirement

No requirement
Continuous
Continuous
No requirement

No requirement
No requirement
No requirement
No requirement
No requirement
No requirement
are regulated and the levels to which
they must be controlled; and the re-
quirements for  monitoring emissions
and operating parameters.  The stan-
           dards apply to new, modified, and re-
           constructed stationary  sources of air
           pollution and are set at levels required
           to control emissions of air pollutants to
                       the greatest degree practicable using the
                       best systems of emission  reduction,
                       considering the costs of such reduc-
                       tion.
1058
                  16-4
                 Journal of the Air Pollution Control Association

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           Source
          category
         Affected
         facility
    Pollutant
                         Emission level
                             Monitoring
                             requirement
   Subpart T:

   Phosphate fertilizer
   plants

   Promulgated
   8/6/75 (40 FR 33152)

   Subpart U:
  Subpart V:
  Subpart W:
  Subpart X:
 Wet process
 phosphoric acid
Superphosphoric acid
Diammonium
phosphate
Triple super-
phosphate
Granular triple
superphosphate
 Total fluorides
Total fluorides
                   0.02 Ib/ton
                                                                           0.01 Ib/ton
Total fluorides     0.06 Ib/ton
                                                         Total fluorides     0.2 Ib/ton
Total fluorides     5.0x10-"
                  Ib/hr/ton
                          Total pressure
                          drop across
                          process
                          scrubbing
                          system

                          Total pressure
                          drop across
                          process
                          scrubbing
                          system

                          Total pressure
                          drop across
                          process
                          scrubbing
                          system

                          Total pressure
                          drop across
                          process
                          scrubbing
                          system

                          Total pressure
                          drop across
                         process
                          scrubbing
                          system
  Subpart Y:

  Coal preparation
  plants

  Promulgated
  1/15/76(41  FR2232)
Thermal dryer
                             Pneumatic coal
                             cleaning equipment
                             Processing and Conveying
                             equipment, storage
                             systems, transfer and
                             loading systems
Particulate



Opacity

Particulate

Opacity

Opacity
0.031 gr/dscf
(0.070 g/dscm)
                                              20%

                                              0.018 gr/dscf
                                              (0.040 g/dscm)
                                              10%

                                              20%
Temperature
Scrubber
pressure loss
Water pressure
No requirement

No requirement

No requirement

No requirement
  Subpart Z:

  Ferroalloy production
  facilities

  Promulgated
  5/4/76(41 FR 18497)

  Revised
  5/20/76 (41 FR 20659)
Electric submerged
arc furnaces
Particulate
0.99 Ib/Mw-hr
(0.45 kg/Mw-hr)
("high silicon alloys")
0.51 Ib/Mw-hr
(0.23 kg/Mw-hr)
(chrome and
manganese alloys)

No visible emissions
may escape furnace
capture system
No requirement
                                                                                                     Flowrate
                                                                                                     monitoring
                                                                                                     in hood
  Before  developing standards for a
particular source category, EPA must
first identify the pollutants emitted and
determine that they contribute signifi-
            cantly to air pollution which endangers
            public health or welfare. The standards
            are then developed and proposed in the
            Federal Register. After a period of time
                         during which the public is encouraged to
                         submit comments on the proposal, ap-
                         propriate  revisions are made  to  the
                         regulations and they are promulgated in
November 1976     Volume 26, No. 11
                                                             16-5
                                                                                                                 1059

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          Source
          category
         Affected
         facility
   Pollutant
                       Emission level
                            Monitoring
                           requirement
   Ferroalloy production
   facilities (cont.)
                           Dust handling equipment
                            Opacity
                            CO

                            Opacity
                  No visible emission
                  may escape tapping
                  system for  >40% of
                  each tapping period

                  15%
                  20% volume basis

                  10%
                                                                       Flowrate
                                                                       monitoring
                                                                       in hood
                         Continuous
                         No requirement

                         No requirement
   Subpart AA:

   Iron and steel
   plants

   Promulgated
   9/23/75 (40 FR 43850)
Electric arc Furnaces
Particulate

Opacity
(a) control
   device
(b) shop roof
                           Dust handling equipment
                            Opacity
0.0052 gr/dscf
(12 mg/dscm)

3%

0, except
20%—charging
40%—tapping
                  10%
No requirement
Continuous

Flowrate
monitoring
in capture hood
Pressure
monitoring
in DSE system

No requirement
the Federal Register. To cite such a
promulgation, it is common to refer to it
by volume and page number, i.e., 36 FR
24876, which means Volume 36, page
24876 of the Federal Register. The table
gives such references for the promulga-
tion and subsequent revisions of each
standard listed.
  Once a year, all regulations that have
been published in the Federal Register
during that year are codified for inclu-
sion in the Code of Federal Regulations
(CFR). Only the regulations are codi-
fied; the preambles which appear with
the regulations in the Federal Register
are not included in the CFR. The CFR
is divided into 50 titles which represent
            broad areas subject to Federal regula-
            tion. Each title is divided into chapters
            which  usually, bear the name  of  the
            issuing agency. Each chapter is further
            subdivided into parts covering specific
            regulatory areas. EPA's regulations are
            included in Title 40—Protection of the
            Environment, Chapter  I—Environ-
            mental Protection Agency. Breaking the
            classification down further, Subchapter
            C covers regulations concerning  Air
            Programs which is then broken down
            into more specific parts. Part 60 is titled
            "Standards of Performance for New
            Stationary Sources," thus the reference
            in the table heading to 40 CFR Part
            60.
                         The table lists all standards of per-
                       formance  promulgated through June
                       1976. The complete regulations for these
                       standards are included  in  the CFR
                       which  was revised July  1, 1976, and
                       contains Parts 60 to 99. Any regulations
                       proposed or promulgated  between July
                       1,1976, and July 1,1977, will appear in
                       the Federal  Register (published daily
                        Acept Saturday and Sunday) and will
                       b3 codified in the 1977 revision to the
                       CFR. Anyone wishing to subscribe to the
                       Federal Register or purchase the CFR
                       should contact the Superintendent of
                       Documents, U.S. Government Printing
                       Office, Washington, DC 20402.
1060
                                                      16-6
                                              Journal of the Air Pollution Control Association

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CHAPTER XVII.
VISIBLE EMISSION STANDARDS
OF THE UNITED STATES
                   Volume 2 of "The World's Air Quality Management
                   Standards," EPA publication No. EPA 650/9-75-001-b by W.
                   Martin and Arthur C. Stern, gives visible emission
                   standards in existence as of 1973 for 49. states, the
                   District of Columbia and Puerto Rico expressed in terms
                   of emissions from mobile sources, aircraft, automobiles,
                   trucks and buses, locomotives, and marine vessels, as
                   well as from a wide variety of stationary sources and
                   the combustion of wood, fossil fuels, and refuse.  This
                   publication is available from the National Technical
                   Information Service, 5285 Port Royal Road, Springfield,
                   Virginia  22161.  Another source of information would
                   be reference to the "Environmental Reporter" available
                   in most libraries.
                   With the requirement of State Implementation Plans by
                   Section 110 of the Clean Air Act, as amended,
                   all 55 states and territories have adopted Ringelmann
                   and equivalent opacity provisions, now commonly referred
                   to as "opacity regulations."  The standard predominantly
                   adopted by the states is 20 percent opacity; however, a
                   few agencies and  the Federal Government in some of their
                   new source performance standards are adopting  10 percent
                   and in some cases zero opacity regulations for many
                   source categories.  There  is now considerable  test
                   data available to support  new  source performance
                   standards with very low opacity limitations.
                                   17-1

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.
   EPA-450/3-78-106
                             2.
                                                           I. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
  VISIBLE EMISSIONS EVALUATION
  TRAINING COURSE 439
  Student   Manual
- AIR POLLUTION
                           5. REPORT DATE
                               September  1978
                           6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
                                                           8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
  Northrop Services,  Inc.
  Air Pollution  Training Institute
  c/o U.S. Environmental Protection Agency  (MD-20)
  Research Triangle Park, NC  27711
                                                           10. PROGRAM ELEMENT NO.
                           11. CONTRACT/GRANT NO.

                                 68-02-2374
12. SPONSORING AGENCY NAME AND ADDRESS
  U.S. Environmental Protection Agency
  Office of Air  Quality Planning and Standards
  Control Programs  Development Division
  Research Triangle Park, NC  27711
                           13. TYPE OF REPORT AND PERIOD COVERED
                                 FINAL
                           14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
  There is an  accompanying instructor's  and operators manual to be  used in conducting
  visible emission training courses.   See  EPA publication EPA-450/3-78-105.
16. ABSTRACT
  This manual  is  to be used by students who are learning how to evaluate ("read")
  visible emissions to the atmosphere  from air pollution sources.   Both black, grey,
  and white plumes  are covered.  The manual discusses sources of air  pollution and
  describes visible emissions to be expected and the reasons why such may occur.  A
  brief review of meteorological phenomena affecting stack plume behavior is given.
  Practices and procedures to be used  in  evaluating visible emissions of both the
  black/grey and  other color nature are described in detail.  The  Ringelmann chart
  and its use  are discussed.  Equipment for generating visible emissions to be observed
  in training  observers is described in detail.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.IDENTIFIERS/OPEN ENDED TERMS  C. COSATI Field/Group
  EPA Method 9
  Smoke
  Air Pollution
  Inspection
  Effluents
  Detection
                training materials
                smoke inspection
                visible emissions
   13 b
   68 A
18. DISTRIBUTION STATEMENT
                       Unlimited.
  Available from National Technical
  Information  Service, 5285 Port Royal
  Road.           -
              19. SECURITY CLASS (This Report)

                  unrl agg-if -i
21. NO. OF PAGES
     240
              20. SECURITY CLASS (Thispage/
                  unclassified
                                         22. PRICE
EPA Form 2220-1 (9-73)
                                            17-3

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