EPA^iO/1-75-007
April 1975
Stationary Source Enforcement Series
GUIDELINES FOR EVALUATION
OF VISIBLE EMISSIONS
CERTIFICATION,
FIELD PROCEDURES, LEGAL ASPECTS,
AND BACKGROUND MATERIAL
Pfil
llrpHLn
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Enforcement
Office of General Enforcement
Washington, D.C. 20460
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EPA-340/1-75-007
GUIDELINES FOR EVALUATION
OF VISIBLE EMISSIONS
CERTIFICATION,
FIELD PROCEDURES, LEGAL ASPECTS,
AND BACKGROUND MATERIAL
by
Robert Missen and Arnold Stein
Pacific Environmental Services, Inc.
1930 Fourteenth Street
Santa Monica, California 90404
Contract No. 68-02-1390,
Task Order No. 2
Project Officer: Kenneth B . Malmberg
Division of Stationary Source Enforcement
Prepared for:
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Enforcement
Office of General Enforcement
Washington, D. C. 20460
April 1975
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iii
ACKNOWLEDGEMENTS
Much of the information contained in this manual was supplied by
staff members of Federal, State and local air pollution control agencies.
The authors are particularly indebted to the following:
Division of Stationary Source Enforcement, Environmental
Protection Agency, Washington, D.C.
K. Malmberg K. Foster
Emission Standards and Engineering Division, Environmental
Protection Agency, "Research Triangle Park, N,C,
R. Neulicht
Bay Area Air Pollution Control District, San Francisco, California
J. Brinkley W. Garoutte
R. Matson
Los Angeles Air Pollution Control District, Los Angeles, California
T. Wilkes R. George
Chicago Department of Environmental Control, Chicago, Illinois
J. Boc J. Winkler
The authors would also like to express their appreciation of the
work perfomred by the staff of Pacific Environmental Services, Inc.,
especially Victor Yamada and Mel Weisburd, and they would also like to
thank Karl Luedtke who acted as a consultant on this contract.
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TABLE OF CONTENTS
Page
LIST OF FIGURES ix
LIST OF TABLES ix
CHAPTER 1. INTRODUCTION ,1.1
1.1 General 1.1
1.2 Purpose of Manual 1.2
CHAPTER 2. TRAINING AND CERTIFICATION PROCEDURES 2.1
2.1 Summary . 2.1
2.2 Classroom Work 2.1
2.3 Evaluation Procedures . 2.1
2.4 Completing the Qualification Form 2.3
2.5 Certification Procedure 2.6
2.6 Apprenticeship Period 2.7
2.7 Recertification Procedure 2.9
2.8 Smoke Generator 2.9
2.8.1 Description 2.9
2.8.2 Specifications 2.9
2.9 Bibliography 2.10
CHAPTER 3. PROCEDURES FOR EVALUATING VISIBLE EMISSIONS IN THE
FIELD 3.1
3.1 Introduction 3.1
3.2 Office Preparation 3.1
3.3 Field Equipment 3.2
3.4 Observer's Location 3.3
3.4.1 Guidelines 3.3
3.4.2 Observation Site-Off Company Property .... 3.3
3.4.3 Observation Site-On Company Property .... 3.3
3.5 Evaluation Procedures ..... ... 3.5
t 3.5.1 Observation Forms ..... 3.5
3.5.2 Types of Opacity Regulations 3.5
3.5.3 Observational Data 3.10
3.5.4 Procedures for Reading Steam Plumes 3.10
3.5.4.1 Attached Steam Plumes 3.10
3.5.4.2 Detached Steam Plumes 3.11
3.5.4.3 Recording Presence of Steam Plumes . 3.11
3.5.5 Recording Observations 3.11
3.5.6 Number of Readings 3.11
3.5.6.1 Guideline 1 3.12
3.5.6.2 Guideline 2 3.12
3.5.6.3 Guideline 3 3.12
3.5.6.4 Guideline 4 3.13
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VI
3.5.7 Sketch 3,13
3.5.8 Photographs ..... 3.13
3.5.9 Number of Observers ....... 3-15
3.5.10 Data Reduction 3.15
3.5.10.1 "Average Opacity" Concept .... 3.15
3.5.10.2 "Time" Ccmcempt , , . 3.15
3.6 Source Inspection ..... ..... 3.15
3.7 Bibliography 3.16
CHAPTER 4. SOURCES OF VISIBLE EMISSIONS .............. 4.1
4.1 Introduction ....... ... 4.1
4.2 Procedures for Non-stack Emission Sources ..... 4.1
4.2.1 Roof Monitors 4.1
4.2.2 Material Handling Operations . 4.3
4.2.2.1 Drilling 4.3
4.2.2'. 2 Crushing 4.3
4.2.2.3 Conveying . 4.3
4.2.2.4 Screening 4.6
4.2.2.5 Stockpiling 4.6
4.2.3 Coking Operations ............. 4.6
4.2.3.1 Charging Operations . 4.6
4.2.3.2 Pushing Operations . 4.8
4.2.3.3 Door Leakage , . . , , 4.8
4.2.3.4 Storage 4.8
4.3 Procedures for Specific Stack Emission Sources . , 4.8
4.3.1 Power Plants, Refinery Heaters, Boilers
and Miscellaneous Fuel Burning Equipment . 4.8
4.3.2 Refineries 4.11
4.3.3 Resin Kettles and Varnish Cooking
Kettles ,.....,,.., 4.13
4.3.4 Sulfuric Acid Manufacturing 4.14
4.3.5 Phosphoric Acid Manufacturing ....... 4.14
4.3.6 Soap and Detergent Manufacturing ...... 4.15
4.3.7 Glass Manufacturing 4.16
4.3.8 Frit Smelters 4.17
4.3.9 Food Processing 4.17
4.3.9.1 Meat Smoking 4.18
4.3.9.2 Fish Meal Driers ......... 4.18
4.3.10 Paint Baking ..4.18
4.3.11 Incinerators , 4.19
4.3.12 Hot-Mix Asphalt Paving Batch Plants .... 4.20
4.3.13 Concrete Batching Plants . . ... 4.20
4.3.14 Stone Quarrying,Rock and Gravel Plants ... 4.21
4.3.15 Mineral Wool Furnaces ........... 4.22
4.3.16 Perlite-Expanding Furnaces 4.22
4.3.17 Feed and Grain Mills 4.23
4.3.18 Pneumatic Conveying and Drying ....... 4.23
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vii
4.3.19 Woodworking Equipment
4.3.20 Asphalt Roofing Felt Saturators ....
4.3.21 Abrasive Blast Cleaning
4,3.22 Zinc-Galvanizing Equipment
4.3.23 Ceramic Spraying and Metal Deposition
Equipment ........
4.3.24 Steel Manufacturing Processes .....
4.3.25 Iron Casting ........
4.3.26 Secondary Brass-and Bronze-Melting
Processes ..............
4.3.27 Secondary Aluminum Melting and Smelting
4.3.28 Secondary Zinc-Melting Processes . , .
4.3.29 Lead Refining
4.3.30 Metal Separation Processes ......
4.3.31 Foundry Sand-Handling Equipment . . . .
4.3.32 Kraft Pulp Mills
4.3.33 Cement Plants .....
4.3.34 Aluminum Reduction Plants .......
4.3.35 Mining .
CHAPTER 5. PROBLEMS ASSOCIATED WITH CONDENSED WATER PLUMES
4.
4.
4.
4.
4,
4,
4,
24
24
25
25
26
26
28
28
29
29
30
31
4.31
4.31
4.32
4.33
4.33
5.1
5.1 General 5.1
5.2 Sources of Water Vapor Plumes 5.2
5.3 Reading Water Vapor Plumes ............. 5.3
5.4 Description of the Psychrometric Chart 5,3
5.5 Example of the Use of the Psyehrometric Chart ... 5.4
5,6
Bibliography
5.8
CHAPTER 6. LEGAL ASPECTS OF OPACITY OBSERVATIONS , - 6.1
6.1 Summary. ...................... 6.1
6.2 Legal Standing of Opacity Observations ....... 6,2
6.3 Summary of Court Cases .........,.,.,. 6.3
6.4 Presentation of Testimony ...... 6.8
6.4.1 General 6.8
6.4.2 Witness Behavior 6.9
6.4.3 Testimony 6.10
6.4.4 Type of Information Required in Testimony . . 6.12
' 6.5 Bibliography .....-..,. 6.14
CHAPTER 7,
EFFECTS OF VIEWING CONDITIONS ON OPACITY READINGS
7.1
7,1 Wind Speed 7.1
7,2 Wind Direction . 7.1
7.3 Viewing Point , . . . 7.1
7.4 Illumination . 7.2
7.5 Background . 7.2
7.6 Atmospheric Stability 7.2
7.7 Atmospheric Haze 7.3
7,8 Sun Angle 7.3
7,9 Effect of Observer Distance on Observed Opacity
7.3
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viii
7.10 Time Interval Between Readings . , 7.5
7.11 Summary of Recommended Observational Procedures . . 7.6
7.12 Bibliography ...... 7.6
CHAPTER 8. APPLICABILITY OF VISIBLE EMISSIONS EVALUATIONS ..... 8,1
8.1 Advantages ............ 8.1
8.2 Objections 8.2
8.3 Summary 8.5
8.4 Bibliography 8.5
CHAPTER 9. PARTICLE SIZES AND THEIR CHARACTERISTICS ........ 9.1
9.1 General 9.1
9.2 Sizes of Particulate Matter Emissions . 9.1
9.3 Effect of Atmospheric Particulates on Climate ... 9.5
9.4 Attenuation of Solar Radiation ..... 9,6
9.5 Health Effects of Atmospheric Particles ...... 9.7
9.6 Removal Mechanisms ..... 9.7
9.6.1 Gravitational Settling ...... 9.7
9.6.2 Coagulation 9.8
9.6,3 Rainout ...... 9.8
9.6.4 Washout. , 9,9
9.6,5 Impaction 9.9
9.7 B;V iography " , 9.9
CHAPTER 10. AIDS FOR EVALUATING VISIBLE EMISSIONS . . . . 10.1
10.1 Introduction ...... , 10.1
10.2 Smoke Charts . 10.1
10.3 Smoke Inspection Guide 10. 1
10.4 Comparators , 10.1
10.5 Smokescope 10.1
10.6 Photography 10.2
10.7 Telephotometers 10.2
10.8 Transmissometers , , , . 10.2
10.9 Laser Techniques 10.3
10.10 Bibliography 10.3
CHAPTER 11. DEFINITIONS , , 11.1
11.1 Pollutant Cloud ............ 11,1
11.2 Haze m 11,1
11.3 Types of Effluent ll.i
11,3.1 Smoke ................... 11,2
11.3.2 Fumes ,...,.. 11.3
11,3.3 Dusts 11.4
11,3.4 Mists * 11," 5
11.3.5 Gases and Vapors . , 11,6
11.4 Bibliography 11.6
CHAPTER 12. METHOD 9 - VISIBLE DETERMINATION OF THE OPACITY OF
EMISSIONS FROM STATIONARY SOURCES 12.1
TECHNICAL REPORT DATA FORM t 13.1
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ix
LIST OF FIGURES
FIGURE 2,1
FIGURE 2.2
FIGURE 3.1
FIGURE 3.2
Smoke School Training Form ......
Certification Letter
Observation Record (Federal Register)
Record of Visual Determination of Opacity
(Federal Register) .....
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
3.3
3.4
3.5
3.6
4.1
4.2a
4,2b
4.3a
4.3b
4.4
4.5
4.6
5.1
5.2
7.1
9.1
Visible Emission Observation Form (Proposed) .....
Record of Visual Determination of Opacity (Proposed) .
Field Sketch
Inspection Data Sheet .
Roof Monitor Emissions ................
Rock Drilling Emissions ........
Crushing Emissions ...........
Conveying-Screening Emissions . . ....
Storage Emissions ..... .....
Topside View of Coke Battery
View of Ovens from Coke Side during Pushing Operations
View of Ovens -from Push Side .
Psychrometric Chart .
Psychrometric Chart . . ,
Effect of Observer Location on Observed Pathlefigth . .
Typical. Size Distribution of Particles in the
Atmosphere Showing Various Average Diameters ...
Page
2.4
2.8
3.6
3.7
3.8
3.9
3.14
3.17
4.2
4.4
4.4
4.5
4.5
4.7
4.9
4.10
5.5
5.7
7.4
9.3
LIST OF TABLES
TABLE 2.1 The Beaufort Scale of Wind-Speed Equivalents . , . .
TABLE 7.1 Variation of Observed Opacity with Distance from
an Elevated Source ....
TABLE 9.1 Particle Sizes and Characteristics ...
TABLE 9.2 Size Distribution (% by Number) From Oil Combustion
TABLE 9.3 Weight Percent Less than Stated Size From Coal
Combustion
2.5
7.5
9.2
9.5
9.5
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1.1
1. INTRODUCTION
I. I GENERAL
Once a plume or effluent is identified as an air contaminant, it
must be measured by some standard to determine whether or not a violation
of thi? law has occurred, or it must be evaluated to determine the size^
or severity of a given air pollution problem.
Visual observation of plumes by field personnel can be an effective
and economical method of determining compliance with air pollution regula-
tions, provided the regulations are based on the visual aspect of plumes,
or on other properties that can be shown to be directly related to the
visual aspect.
The benefits of basing emissions statutes on opacity, or density,
are quite evident, even though equipment and fuel regulations have in-
creasingly assumed precedence in control legislation. When the visual
standard is specific with reference to a cutoff point and time interval,
it is simply and directly enforced. All enforcement officers need do is
observe an emission of an opacity or density beyond that allowed by the
regulations for a minimum time interval in order to cite a violator for
excessive emissions.
Although the visual standard is limited to estimations of particu-
late pollution which obscures vision, its application simultaneously
tends to reduce grain loading, since there is a relationship between
grain loading and opacity, although this relationship is somewhat com-
plex. The standard, therefore, is most versatile in accomplishing gross
4
reductions of atmospheric pollutants in a community, and can be applied
not only to smoke, but to fumes, dusts and mists arising from a variety
of sources.
It should be cautioned, however, that while such benefits can be
assumed, they cannot always be precisely predicted or evaluated. Deter-
mination of opacity and shade of any emission alone gives no specific
measurements of the quantities of contaminants being emitted.
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1.2
1.2 PURPOSE OF MANUAL
The purpose of this manual is to provide the certified visible
emissions evaluator, often referred to as a "smoke reader", with certain
guidelines to be followed when making visual observations of stationary
source emissions. It is intended to supplement EPA policy and procedural
guidelines for making opacity determinations.
Method 9 of Appendix A to Section 60 of the Federal Register Vol.
39, No. 219, November 12, 1974, is the basis for the visual observation
procedures. Any subsequent revisions to Method 9 that may be published
in the Federal Register should take precedence over the procedures given
in this manual.
The manual is primarily intended to assist EPA personnel:
(a) in making field evaluations of the opacity of visible
emissions in accordance with the approved procedures,
(b) in ensuring that all necessary observations are made, and all
pertinent information is obtained and recorded in a standard, clear for-
mat , and
(c) by providing recommended procedures to be adopted in preparing
and presenting a court case, should the results of the field investigation
indicate that the visible emission regulation was violated.
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2.1
2. TRAINING AND CERTIFICATION PROCEDURES
2.1 SUMMARY
To become a qualified visible emissions evaluator the student must
successfully complete a training school, normally of three days duration,
presented by a Federal, State or local air pollution agency, or educational
establishment. The training school consists of a series of lectures, and
slide and film presentations, in addition to the actual training of the
student to evaluate the opacity of visible emissions.
2.2 CLASSROOM WORK
The purpose of the classroom work is to present to the student sufficient
background material such that competent evaluations of the opacity of
visible emissions can be made in the field during enforcement operations,
and to enable these observations to be translated into testimony that will
be admissable as evidence in any future court or hearing board proceedings.
The classroom work should consist of a description of the Ringelmann chart,
the definition of opacity, a description of aids that are available for
evaluating visible emissions, procedures to be followed in tha field,
training procedures, a description of the smoke generator, sources of
visible emissions, the problems associated with water vapor plumes, pre-
paration of the evidence, courtroom and hearing board procedures, presen-
tation of the evidence and some basic meteorology.
2.3 EVALUATION PROCEDURES
The aim of the training school is to produce a qualified observer
whose judgment of plume density will be accurate and unaffected by
variable field conditions. To ensure uniformity of observing conditions,
as far as is possible, the following procedures should be adhered to:
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.
b, Reading should be made at right angles to the plume
direction, and from any distance necessary to obtain a
clear view of the stack and background.
c. Readings should be taken at the densest part of the plume
i.e., through the center of the plume immediately above
the stack exit.
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2.2
d. The student should, if possible, read the plume against
a contrasting background, such as blue sky for black
plumes or a dark background for white plumes.
e. The student should not stare at the plume, since
staring at the plume tends to cause eye fatigue which
produces erroneous readings.
f. An indication will be given by the examiner to the
students to inform them when a reading should be taken.
This will usually be the sounding of a horn. When the
horn is sounded the student should look up at the plume
and make the opacity determination as soon as possible.
Usually the control settings on the smoke generator
will not be changed for a few seconds after the horn has
sounded but the opacity can vary slightly even though the
control settings remain unchanged. For this reason it is
good practice for the student to look at the plume and take
the reading immediately when the horn is sounded, since
the time taken to accomplish this is approximately the same
as the time taken by the smoke to travel from the trans-
missometer location to the stack exit. The two readings
are therefore taken through approximately the same cross-
section of smoke.
g. Readings will be taken when the opacity, as determined by
the transmissometer readout, has stabilized, which will
be about every 15 seconds.
The operator of the generator decides when the opacity, as given
by the transmissometer readout, is constant and will sound the horn to
indicate that the reading should be taken. The control settings will
remain constant for a few seconds after which another control setting
will be selected for the next reading.
If the local agency permits it, the student may use small, hand-
held Ringelmann Charts or other aids as guides in judging the black and
gray shades. However, it is recommended that the student not use any
of these aids, since within a very short period of time the student will
gain sufficient confidence in his ability in making the observations that
these aids will become of no significant benefit.
If the student wishes to be qualified as a certified smoke reader
under nighttime conditions a separate test must be taken. For night-
time reading a light source is required and the student should be posi-
tioned such that the light is immediately behind the plume. However, at
this time EPA does not have any approved procedures for evaluating plume
opacity under nighttime conditions.
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2.3
Normally training will only be conducted on plumes containing no
condensed water vapor. If the plume does contain condensed water vapor
the observation should be made either just after the point where the
water droplets evaporate, or if the steam plume is detached from the stack,
readings can be taken before the vapor condenses, immediately above the
stack exit.
2.4 COMPLETING THE QUALIFICATION FORM
A blank qualification form is given below in Figure 2.1.
All entries must be made in ink.
The observer's name, affiliation and date are self-explanatory.
The time should be the approximate time when the run began.
The wind speed should be estimated by the observer to within a 3 to
5 mile per hour range. If an anemometer is not available, the wind speed
may be estimated by using the Beaufort wind scale given in Table 2.1.
The wind direction can be estimated to eight points of the compass
(N, NE, etc) by observing which way a flag is blowing, or by seeing which
way a few blades of grass are blown when thrown into the air. The North
direction can be obtained by reference to a map.
The 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.
The pbserver's orientation with respect to both the plume and the
sun should be indicated in the "Observer's Position."
Each run during the qualification session consists of 50 emissions,
25 of black, or grey, smoke and 25 of white smoke. The runs are numbered
successively, beginning with 1-B and 1-W, and continuing with 2-B, 2-W,
etc., where B refers to black smoke and W refers to white smoke.
The student's observations are entered in the "Observer Reading"
columns, with readings for both black and white smoke being entered in
percent opacity. The student's estimate of the opacity is made to the
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2.4
Figure 2.1: NATIONAL ENVIRONMENTAL RESEARCH CENTER
RESEARCH TRIANGLE PARK, NORTH CAROLINA
SMOKE SCHOOL TRAINING FORM
1. Name of Observer
2. Affiliation
3. Dale
4. Wind Speed,
5. Observers Position
6. Corrected By
Time,
Direction,
Sky Condition,
Record Black and/or White Smoke in Percent Opacity (for example: 5 percent smallest division)
RUN NO,
0
Z
aa
.E
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ro
01
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1
2
3
4
5
6
7
8
9
10
11
12
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=» ,=
Ju '-a
•" S
o£
Transmissometer
Reading
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0
1
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13
14
15
16
17
18
19
20
21
22
23
24
25
S.5
03 ~>3
"2
o c:
Transmissometer
Reading
•f Deviation
— Deviation
RUN NO.
o
Z
00
cr
•S
re
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1
2
3
4
5
6
7
8
9
10
11
12
S.s
o3 ^
^ ?J
-a «
o1^
Transmissometer
Reading
+ Deviation
—Deviation
0
E:
cxo
c
ta
ra
(U
CC
13
14
15
16
17
18
19
20
21
22
23
24
25
Observer
Reading
Transmissometer
Reading
c=
o
ra
"±»
o>
Q
+
—Deviation
7. Run Number
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)
' Total No. of Readings
14. Number of Readings 20% Deviation and Over
EPA(DUR)255
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2.5
Table 2.1: 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 fay smoke drift
but not fay 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 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.
Limits of Velocity
33 feet (10 m)
above level ground
(MPH)
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
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2.6
nearest 5 percent. The lowest possible reading is 0 - indicating a
clear plume - and the highest is 100 - indicating a completely opaque
plume.
After the 50 evaluations have been made the form is checked by a
fellow student. The opacity as determined by the transmissometer is
entered in the "Transmissometer Reading" columns, and the rest of the form
is then completed.
2.5 CERTIFICATION PROCEDURE
The smoke opacity evaluation training requires that the student must
observe and successfully evaluate the opacity for a run of 50 consecutive
smoke emissions - 25 of black smoke, and 25 of white smoke - in accordance
with the EPA certification procedures.
The current criteria are:
1. The deviation of any reading must not be greater than 15%.
2. The average deviation for both the black and white smoke
runs must be less than 7.5%.
A Smoke School Qualification Form similar to the one shown above in
Figure 2.1 is to be used to record the readings and deviations, and to
compute the information required for qualification.
Initially there will be some emissions of both black and white smoke
during which time the opacity will be announced while the smoke is being
emitted, so that the student can become familiar with the procedures and
learn to correlate his observations with the announced readings. After
the familiarization period, there will be at least one practice run of
50 emissions.
Following the practice run, there will be certification runs of 50
emissions (25 black and 25 white). To qualify as a certified visible
emissions evaluator the student must achieve the criteria given above,
i.e., average deviation less than 7.5% and no deviation greater than 15%,
for both the black and white smoke.
After the qualification criteria have been achieved the student
should ensure that the form has been completely filled in. The student
should also check the transmissometer readings on the form against the
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2.7
actual transmissometer readings recorded by the examiner, which will be
on display expressly for this purpose. It is also recommended that the
student check the arithmetic on the form. The reasons for these checks
are to find any errors in transcription or arithmetic that might have
occurred, which would preclude the student from qualifying, even though
the student believes in good faith that the qualification criteria have
been met.
After the student has checked and completed the form he submits it to
the examiner, who will check all the data and the arithmetic on the quali-
fication form. To those students who successfully meet the qualification
criteria, the examiner will send written affirmation in the form of a
letter, together with a copy of the student's qualification form. An
example of this letter is shown in Figure 2.2.
The original of the completed qualification form is retained by the
examiner in his office, so that it may be available for presentation in
any future legal proceedings that may occur, as evidence that the inspec-
tor has been certified as a qualified visible emissions evaluator by a
recognized air pollution agency.
The certification is valid for a period of six months.
2.6 APPRENTICESHIP PERIOD
Under the Method 9 procedures an inspector becomes a fully qualified
visible emissions evaluator as soon as he has attended a "Smoke School"
and met the certification criteria. However, it is suggested that before
he is regarded as being fully-qualified the newly-certified inspector
should demonstrate his ability to satisfactorily evaluate visible emissions
»
in the field during an "apprenticeship period" under the guidance and
supervision of an experienced inspector.
Since this apprenticeship period is not part of the current EPA pro-
cedures there are no specific guidelines that should be adopted, but it
is suggested that during this period the trainee inspector should perform
about ten field evaluations on plumes of various colors, and if possible,
on at least one plume containing condensed water vapor.
The purposes of the apprenticeship period are to demonstrate to the
-------
2.8
ENVIRONMENTAL PROTECTION AGENCY
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27711
April 30, 1975
Mr. Kenneth B. Malmberg
U.S. EPA, Region V
1 North Wacker Driver
Chicago, Illinois 60606
Dear Mr. Malmberg:
Please be advised that you successfully completed our recent "Visible
Emissions Evaluation" course. Having attended the lectures (April 8,
1975) and participated in the smoke evaluation sessions, you met the
following certification criteria;
1. The average deviation for the sets of 25 black smoke and
25 white smoke emissions was less than 7.5%.
2. The deviation of each reading was 15%, or less.
This certification is valid until October 7, 1975.
Sincerely yours,
Dennis P. Holzschuh
Physical Science Technician
Engineering and Enforcement Section
Air Pollution Training Institute
Figure 2.2: CERTIFICATION LETTER
-------
2.9
supervisor of the Inspection Department that the trainee inspector is not
only capable of evaluating a wide variety of sources under various weather
conditions, but is familiar with the field equipment and the data reduction
procedures.
2.7 RECERTIFICATION PROCEDURE
To become recertified it is not necessary for the inspector to attend
the lecture program again - achieving the certification criteria on the
emissions evaluation test is sufficient. Otherwise, the procedures are
identical to those described above in the preceding sections.
It is recommended that even after an inspector has successfully met
the criteria, that he continue to make evaluations of the opacity of the
emissions to gather additional experience and improve his accuracy. The
results of these evaluations need not be given to the examiner.
After becoming recertified the inspector is qualified to determine
the opacity of visible emissions for a period of six months from the date
of the test.
2.8 SMOKE GENERATOR
2.8.1 DESCRIPTION
In order to train personnel to evaluate visible emissions, it is
necessary to have a system which will produce both black and white plumes,
and is equipped with an instrument for measuring and recording the amount
of light transmitted by the smoke. Several companies are now manufacturing
these devices, and at least one smoke generator is now available for train-
ing purposes in most states.
White smoke is usually generated by vaporizing fuel oil in the
exhaust manifold of a gasoline engine, and black smoke is generated by
burning benzene in a combustion chamber.
2.8.2 SPECIFICATIONS
The specifications for the smoke generator are given in the Method 9
procedures published in the Federal Register. The current Method 9 pro-
cedures are given in Section 12 of this manual.
-------
2.10
2.9 BIBLIOGRAPHY
1. Conner, W.D. and J.R. Hodkinson, Optical Properties and Visual
Effects of Smoke Stack Plumes, DREW, PHS Publication No.
999-AP-30, 1967.
2. Coons, J.D., et al, Development, Calibration, and Use of a
Plume Evaluation Training Unit , J. Air Poll. Control Assoc.
15, 199-203, May 1965.
3- Sholtes, R.S. Operation of the Mark II, Smoke Observers' Training
Unit, 1967.
-------
3.1
3. PROCEDURES FOR EVALUATINGVISIBLE EMISSIONS IN THE FIELD
3.1 INTRODUCTION
This chapter outlines the steps to be followed to satisfactorily
evaluate visible emissions in the field. Recommended guidelines are
included for the collection of all information that is necessary to
document a violation of the opacity regulation and for use in any subse-
quent legal proceedings.
3.2 OFFICEPREPARATION
In most instances the inspector will have sufficient notice before
making a field observation to adequately prepare for the visit. Prepara-
tion is a very important aspect of the inspector's work. The following
items concerning the facility in question should be researched.
a) Plant location
b) Names and positions of responsible plant contacts
(company officers or management personnel)
c) Type and number of processes
d) Type of process to be observed
e) Process operating conditions
f) Type and location of control equipment
g) Probable location of source emissions
h) Possible observation sites
I) Regulations applicable to the source
j) Status of source with respect to any variance or exemption from
the agency's rules and regulations. Observation is not required
if the source is on a variance, or exempt from the regulations.
k) Involvement of steam plume, if any. The procedure in the
"Condensed Water Vapor Plume" section will indicate if a steam
plume might be present, and could indicate a time of day when
a steam plume might not be present.
Familiarity with the opacity regulations, and the regulation exemp-
tions will help to prevent an inspector from documenting what he perceives
to be a violation when in actuality it is not. For example, although
Colorado regulations state that an opacity greater than 20% constitutes
a violation, a source may emit visible emissions of 40% opacity for 3
minutes out of 60 minutes if it is undergoing process modification, start
up, cleaning, etc.
-------
3.2
The recommended procedure is to determine a vi - ~* .1 ~ion regardless of
plant operation (e.g. for Colorado, an emission greater than 20% for any
time period greater than 3 minutes would constitute a violation). In this
way the investigator knows that a documented and enforceable violation
has occurred without having to fear a company reporting at a later date
that the readings (in the case of Colorado, greater than 20%, but less
than 40% opacity) cannot be utilized because the plant was undergoing a
process change at ths time of the visible emission evaluation.
3.3 FIELD EQUIPMENT
The following equipment should be available for use by the
observer:
a) Hard hat
b) Stopwatch
c) Clipboard, note pad and at least two pens (Pencils must not be
used for recording opacity readings).
d) Geologist's compass
e) Air velocity meter
f) Range finder
g) Psychrometer
h) Binoculars
i) Camera
j) Topographic maps
k) Necessary forms, including ample spare copies:
1. Observation Form
2. Summary Form
3. Sketch Form and Data Sheet, if standard formats are used.
1) Safety goggles
m) Safety shoes
n) Respirator face mask
o) Pouch, to carry the equipment
NOTE: Items 1, m and n are required only if site conditions
warrant their use.
The equipment should be inspected in the office before going out on
a field observation in order to ensure that it is in good working order.
-------
3.3
3.4 OBSERVER'S LOCATION
3.4.1 GUIDELINES
The evaluator should select an observation point consistent with
the following guidelines:
1) The line of sight from the source to the observer should be
unobstructed,
2) The line of sight should ba at right angles to the wind direction.
3) '.he sun should be oriented within a 140 sector to the observer's
A) The location should be safe.
5) If the pollutants are emitted at ground level, the observer
should be as close to the source as possible.
6) If the pollutants are emitted from an elevated position, the
inspector should be at a suitable distance from the source.
(See Section 7.9) .
7) With good visibility it is suggested that the observer should
be within about a quarter of a mile from the source.
8) When visibility is restricted, the observer should be within
a distance that is about one quarter of the visual range,
9) When evaluating emissions from rectangular outlets, the ob-
server should be positioned at right angles to the longer axis
of the outlet.
3.4.2 OBSERVATION SITE-OFF COMPANY PROPERTY
If a position can be selected that is not on company property, that
meets all the above requirements, the evaluator may begin the field
evaluation of the source in accordance with Section 3.5. The inspector
should not notify company officials that an evaluation is to be conducted.
3.4.3 OBSERVATION SITE-ON COMPANY PROPERTY
*
If the evaluator decides that it is not possible to select a suit-
able point that is not on company property from which to make the evalua-
tion, then the evaluation should be carried out from a location on company
property.
If a site can be selected that is on company property, but is
accessible to the public, the evaluator may begin the evaluation without
notifying company officials.
If, however, a site meeting the criteria given in Section 3.4.1 is
-------
3.4
on company property, that is not publicly accessible, then the evaluator
must obtain permission from a responsible company official to enter the
plant. Before notifying the company of the proposed evaluation, however,
it is recommended that the inspector take several opacity readings from
the best available site off company property. These preliminary
readings can then be used as a comparison between stack emissions before
and after company notification. If a noticeable change is observed, the
inspector should record this fact.
If it is necessary to enter the plant property in order to make the
observations, every attempt should be made to ensure management cooperation.
Entering a plant, especially for the first time, can present a delicate
situation; tact and courtesy are most important considerations under these
conditions. The evaluator should follow the steps below to correctly and
courteously enter the plant for the purpose of conducting the evaluation.
a) When entering the plant be prepared to state your name,
affiliation and position, and have identification avail-
able for presentation.
b) State the nature of your visit and request an interview
with a company officer or responsible employee of the
company.
c) Describe to the company representative the nature of work
or duties you intend to perform on the premises and request
their permission to do so.
d) Should you meet with refusal, and if attempts to discuss the
situation are unsuccessful, contact your office for further
instructions.
e) Should you be given permission to proceed to a specific area
without escort, ask for directions and go there directly.
f) Spend as little time as possible with entrance procedures
so as not to become liable to charges of "interfering with
company work,"
g) fto not sign any documents, such as liability waivers or
others, that are conditions for your presence on the company
premises. Discussion between your responsible officer and
the plant official are the best means of resolving any
problems that might arise in this matter.
h) Maintain a business-like and cordial relationship with
company officials and employees at all times.
i) The evaluator should take note of the length of time he
is kept waiting, cooperation and attitude of plant personnel,
and any changes in operating conditions which may result from
his presence. The latter may affect the credibility of the
-------
3.5
evaluator'a findings should he later be asked about these
conditions during the presentation of testimony,
j) Record the name, title and telephone number of the company
official and note the time that the official was informed
that an evaluation was to be conducted.
The inspector's ultimate objective is the improvement of the ambient
air quality by ensuring that sources emit pollutants in compliance with
the regulations. This objective can be achieved much more readily with
the willing cooperation of the company. The visible emissions evaluation
affords the inspector an opportunity to engage in some "public relations"
work. The inspector should therefore endeavor to maintain a polite, yet
professional, attitude while he is on company premises.
3,5 EVALUATION PROCEDURES
3.5.1 OBSERVATION FORMS
Once a suitable observation site has been selected the inspector
should begin the evaluation of the source, recording all the pertinent
information on an approved set of forms.
Two sets of forms are included in the manual:
1) Those forms that appeared in the Federal Register, Volume 39,
No. 219, dated Tuesday, November 12, 1974, and included as
Figures 3.1 and 3.2.
2) Suggested alternative forms, included as Figures 3.3 and 3.4.
The forms in the Federal Register represent the approved forms to be
used when making a visual determination of opacity at the time this manual
was written. Although Method 9, the reference method for visual determina-
tion of the opacity of emissions, has been finalized, EPA is still consi-
dering additional changes to the observation time, and the method of
evaluating'exception periods and non-consecutive violations. The forms
included as Figures 3,3 and 3.4 have been proposed as possible improvements
to the Federal Register forms.
The forms that appear in. any subsequent issues of the Federal Register
should be used for recording the field data.
3.5.2 TYPES OF OPACITY REGULATIONS
At the present time there are two types of opacity regulations in
use. These are based on the following concepts:
-------
COMPA
LOCAT
TEST
PATE
Hr.
l—
FIGURE 3 . 1 OBSERVATION RECORD PASE OF
NY OBSERVER
ION
NUMBER
Min.
0
£
TYPE FACILITY
POIHT OF EMISSIONS
1 STEAM PLUME
Seconds uchgc'-; 1f anpHeable)
i
1 3 ]
4 1
5
I
!
1 '6
i 7
9
10
11
L_
12 1 1
14
i 15
I 16
17
.. j ''*-
[ 19
__n
—
2U
n
22
23
24
<:5
V6
2!
28
29
—
—
„.
1 |
1^ .-
|
^-1
t I
>
i
L
"~
COMMENTS
C
(Cor
:OM?ASY
.OCATION
TEST
DATE
Hr.
NUMBER
f«n.
30
31
32
33
3d
3b
36
3?
38
39
40
41
1 42
43
45
46
— yr~
49
50
Seconds
0
IS
30 1 '13
l
Si |
5?
53
54
r 55
1 56"
_kL
59 1
_0_
1
1
1111
I
fcl
At
I IB Do;.!-,
OESERVATIOS RECOM
OF
OBSERVER
TYPE FACILITY''
POINT OF EMISSIONS
-------
COMPANY
LOCATION
TEST NUMBER,
DATE
TYPE FAC!LITY_
CONTROL DEVICE:
FISWE 3.2
RECORD OF VISUAU DETERMINATION OF OPACITY
PAfiE cf.
HOURS OF OBSERVATION
OBSERVER
OBSERVER CERTIFICATION DATE_
OBSERVER AFFILIATION,
POINT OF EMISSIONS
HEIGHT OF DISCHARGE POINT
O
z
O
O
CLOCK TIME
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.)
PLl)!€ DESCRIPTION
Color
Distance Visible
OTHER IZIFORJIATIOf!
Initial
Final
SUWttRY OF AVERAGE OPACITY
Readings ranged from
to
Set
Number
T-fr-r.
Start-End
Opacity
Sun
Average
opacity
The source was/was not 1n conpliance with
the time evaluation was made.
.at
-------
Source Name
Address
3.8
Figure 3,3: VISIBLE EMISSION OBSERVATION FORM
„___ Observer
Dace
Observation Point:
Stack: Distance From Height
Wind: Speed Direction
Sky Condition:
Color of Emission:
Ambient Temp; Dry Bulb °F
Wet Bulb ~ t _ °F
Relative Humidity:
Observation began Ended
•
Observer s
Signature:
Certification Date:
Comments :
0
1
2
3
4
5
6
i
8
9
10
11
1?
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
0
15
30
45
30
31
32
33
34
35
36
J/
38
39
40
41
4?
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
0
15
30
45
l_
i
-------
Figure 3.4: RECORD OF VISUAL DETERMINATION OF OPACITY
Page
of
COMPANY
LOCATION
TEST NUMBER
DATE
TYPE FACILITY
CONTROL DEVICE
HOURS OF OBSERVATION
OBSERVER
OBSERVER CERTIFICATION DATE
OBSERVER AFFILIATION
POINT OF EMISSIONS
HEIGHT OF DISCHARGE POINT
NOTE: Record the following information prior to, and upon completion of, observations at each source. If observations are made over
an extended period of time, additional recordings should be made, as applicable
Initial
Final
Clock Time
OG^KVER LOCATION"
Distance to Discharge (ft.)
Direction from Discharge
Height of Observation Point (ft.)
METEOROLOGICAL CONDITIONS:
Ambient Temp ( F) Dry Bulb/Wet Bulb
Relative Humidity 7,
Wind Direction
Wind Speed (mph)
SKY CONDITIONS:
Z Cloud Cover
PLUME DESCRIPTION:
Color
Distance Visible (ft.)
Other data
,^"
^^-"
,--''
^^
^~^~
^,*^
.x-"'
^^
*
Opacity 0-20 21-30 31-40 41-60 61-80 81-100 JTotal [
No. of Readings) |
i J
•
Readings over Z, Average Opacity = 7.
Readings ranged from to % opacity.
Opacity exceeded % for mine sees.
Regulation:
-------
3.10
a) Opacity is to be averaged over a specified time period—six
minutes in the current Method 9 procedures—and this average
opacity is compared to the regulation limit.
b) There is no need to average the observed opacities—any ob-
served opacity that is greater than the regulation limit
constitutes a violation.
Usually the opacity regulation will permit the source to emit
visible emissions greater than the regulation limit for a specified time
interval—often this exemption period is three minutes in a one hour
period.
Figures 3.1 and 3.2 are used if the "average opacity" concept
is employed.
Figures 3.3 and 3.4 are used if the "time" concept is employed.
3.5.3 OBSERVATIONAL DATA
The inspector should begin the evaluation by recording the source
identification parameters, site location and ambient weather conditions
on the observation forms, Figures 3.1 and 3,2, or Figures 3.3 and 3.4.
A photograph of the source should be taken at this point.
3.5.4 PROCEDURES FOR READING STEAM PLUMES
This section describes procedures for reading steam plumes. The
nature of steam plumes is treated in detail in Volume II. Chapter 5 treats
the sources of steam plumes, how they can be eliminated and how to use a
psychrometric chart,
3.5.4.1 ATTACHED STEAMPLUMES
When condensed water vapor is present within the plume as it emerges
from the emission outlet, opacity observations should be made beyond the
point in the plume at which condensed water vapor is no longer visible.
The observer should record the approximate distance from the emission outlet
to the point in the plume at which the observations are made.
-------
3.11
3.5.4.2 DETACHED STEAM PLUMES
When water vapor in the plume condenses and becomes visible at a dis-
tinct distance from the emission outlet, the opacity of emissions should be
evaluated at the emission outlet prior to the condensation of water vapor
and the formation of the steam plume.
3.5.4.3 RECORDING PRESENCE OF STEAM FLUMES
If the forms in the November 12, 1974 Federal Register, Figures3.1
and 3.2, are used, a check mark should be placed in the appropriate box
to denote the presence of a steam plume.
If the suggested alternative forms, Figures 3.3 and 3.4 are used, a
note indicating the presence of an attached or detached steam plume should
be made in the "Comments" section.
3.5.5 RECORDING OBSERVATIONS
Observations should be made at the point of greatest opacity in that
portion of the plume where condensed water vapor is not present. The ob-
server should not look continuously at the plume, since this can lead to
eye fatigue, but instead should observe and evaluate the plume momentarily
at 15-second intervals.
3.5.6 NUMBER OF READINGS
In order to meet the requirements of EPA method 9, the required number
of readings is as follows:
1) In all cases, a minimum of 24 readings must be taken corres-
ponding to six minutes of observation.
2) In- cases where the regulation permits an exemption period
for excess emissions, a minimum of 24 observations must be
recorded over and above the number of readings equal to the
permissible exemption period. For example, if the regula-
lation permits 3 minutes of excess emissions in any hour,
a minimum of 12 readings (3 minutes) plus 24 readings (6
minutes) must be recorded. That is, a total of 36 readings
(9 minutes) must be recorded in order to establish a single
six-minute average for that hour.
While it is a simple matter to establish the minimum number of
readings necessary to meet the requirements of Method 9, it is not a
simple matter to establish the number of readings necessary to document
-------
3,12
an enforceable violation of the opacity regulations. Whether there is
sufficient proof that a violation did occur will depend upon the amount
of evidence collected in the field. The more readings above the regula-
tion limit that are observed, the stronger will be the ensuing case if the
results of the evaluation are used as evidence at any subsequent legal
proceedings,
Some guidelines to aid in this matter are given below:
3.5.6.1 GUIDELINE 1;
In most cases, the amount of evidence that should be regarded as
the minimum necessary to document an enforceable violation should consist
of at least one set of 24 readings with an average opacity of at least 10%
above the regulation limit.
3.5.6.2 GUIDELINE2:
Concerning regulations based on actual opacity instead of average
opacity, it is recommended that before legal proceedings are initiated,
the observed opacity should exceed the regulation limit by at least 10%
for at least three minutes in any hour; this is in addition to any exemp-
tion time period that may be permitted for excess emissions,
3.5.6.3 GUIDELINE 3:
Weather conditions during the observation period should be taken into
account when considering the number of observations and the degrees of
excess emissions necessary to document a violation. Tests conducted by
EPA (See Section 7.5), indicate that the possibility of a positive bias
is greatest when a contrasting background is used (i.e. - white plume,
blue sky). In a similar manner when a noncontrasting background is used
(i.e. - white plume, overcast sky) the possibility of a negative bias is
greatest. In factj the test results indicate that the chance for positive
error in determining the opacity of white plumes is essentially non-exis-
tent when a noncontrasting background is present. This should be taken
into consideration when the inspector is determining the amount of data
needed to verify a violation.
-------
3.13
3.5.6.4 GUIDELINE 4;
The actual opacity of emissions from the source can be used as a
further guideline in determining the number of readings that are necessary,
e.g. if the opacity of the emissions is 100% an observation time of six
minutes in excess of. the exemption period should be sufficient evidence to
ensure that the violation could be enforced. If, however, the opacity of
the emissions averages about 30%, in those areas where the regulation limit
is 20%, considerably more readings would be necessary.
3.5.7 SKETCH
A reasonably detailed sketch should be drawn. It should include
sufficient detail to allow a person who has not visited the site to deter-
mine the source that was evaluated and the location of the observation
point. The sketch should depict:
Source Location
Observer Location
Distance from observer to source
North direction
Wind direction - from which wind is blowing
Sun position
Landmarks and nearby streets
Plume type
Distance plume visible
An example of a sketch is shown in Figure 3.5.
3.5.8 PHOTOGRAPHS
Photographs should not be taken during the observation period. They
&
should be taken before and after the observation is made. Even though
photographs cannot be used as evidence in court, they do put on permanent
record conditions as they existed at the time of the observation. The use
of a 35 mm - type camera is recommended, so that good photographs are
ensured.
Each photograph should be identified - including such information as
date and time the photograph was taken, the source and the position from
which the photograph was taken.
-------
3.14
FIELD SKETCH
Looping Plume
Plume Visible
for 100 Yards
Observer A
Postion t-1.
Date:
JSjovember 1, 1974
Time:
1400-1500
Observer: Robert Missen
Source: CGE Power Plant
Unit 1, Santa Monica, Calif.
NORTH
Sun
Position
Wind Direction (SE)
Pico Blvd.
St. John's
Church
Observer's
Location
Unit 1
14th Street
Unit 2
Power Plant
Property Line
Comments: No steam plume visible
Observation made from St. John's Church parking lot.
Figure 3.5: FIELD SKETCH
-------
3.15
3.5.9 NUMBER OF OBSERVERS
Only one inspector should evaluate a given source during any given
period of time. In cases where the source is continually evaluated and
reevaluated over extended periods of time (days and months), it is accep-
table, indeed preferable, to have different inspectors perform the evalua-*
tions.
3.5.10 DATA REDUCTION
3.5.10.1 DATA REDUCTION - "AVERAGE OPACITY" CONCEPT
Opacity is determined as an average of all the readings taken over
a time period corresponding to the applicable standard. For example, for
a six minute standard, the opacity is defined as the average of a "set"
of any 24 consecutive readings taken over a six minute period at 15 second
intervals. The observations recorded on the observation record sheet,
Figure 3.1 are divided up into sets of 24 consecutive readings and the
average opacity for that set is determined by dividing the sum of the
readings by 24.
The sum and average opacity for each set is entered in the "Summary
of Average Opacity" table in Figure 3.2. The sets need not be consecutive
in time, but in no case should two sets overlap.
3.5.10.2 DATA REDUCTION - "TIME" CONCEPT
The opacity readings recorded on Figure 3.3 should be summarized by
completing the items on the right hand side of Figure 3.4.
3.6 SOURCE"INSPECTION
After the visual observation has been made, whether from a location
inside or outside the plant property, an inspection of the source that was
evaluated, should be made. To do this, the highest ranking official of
the company, who is readily available, should be contacted.
At all times during the inspection the inspector should maintain a
business-like relationship with company personnel. If requested by the
company representative, the inspector may give a brief discussion of the
purposes of the opacity evaluation.
-------
3.16
The inspector should not under any circumstances indicate whether a
violation of the regulations was observed, and indeed at the time of the
inspection a determination of whether a violation was observed will not
have been made, since the information on Figures 3.3 or 3.4 has to be
completed before such a determination can be made,
During the Inspection, information concerning the source should be
obtained from the company official. This information can be obtained by
asking such questions as:
1) Were the plant and the source of interest operating normally
at the time the evaluation was conducted?
2) Are there, any control devices associated with the source?
Were they operating properly?
3) When were the source and its control devide installed
or modified?
Since an inspection report has to be written after the evaluation
has been made, the relevant information about the source should be collected
and recorded in a standard format. A data sheet similar to Figure 3.6
should be used to record this information.
3.7 BIBLIOGRAPHY
1, Lucas.M,The Objective Calibration and Air Pollution Significance of
Ringelmann Numbers, Atmos. Env., pp. 775-780. 1972.
2, Marks, L.S. Inadequacy o£ the Ringelmann Chart, Mech. Eng., p. 681.
1973,
3. Stein, A. Guide to Engineering Permit Processing, APTD-1164, EPA
Office of Air Programs. 1972.
4. Weisburd, M.I. Field Operations and Enforcement Manual for
Air Pollution Control. Volume I: Organization and Basic
Procedures, APTD-1100, EPA Office of Air Programs. 1972.
5. Weit'-urd, M.I. Field .Operations and Enforcement Manual for
Air Pollution Control. Volume II: Control Technology
and General Source Inspection, APTD-1101, EPA Office of
Air Programs. 1972.
6. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries, APTD-1102, EPA Office of Air Programs.
1972.
7. Yocum, J.E. Problems in Judging Plume Opacity, J. Air Poll, Control
Assoc. 13, 36-39. January 1963.
-------
3.17
VISIBLE EMISSIONS EVALUATION DATA SHEET
OBSERVER:
DATE:
COMPANY DATA
COMPANY NAME:
COMPANY ADDRESS:
COMPANY CONTACT: TELEPHONE:
SOURCE DATA
SOURCE IDENTIFICATION:
APPLICABLE RELATION:
OPERATING RATE:
NORMAL OPERATING RATE:
CONSTRUCTION/MODIFICATION DATE:
CONTROL SYSTEM DATA
TYPE:
DESIGN EFFICIENCY:
INSTALLATION DATE:
COMMENTS:
Figure 3.6: INSPECTION DATA SHEET
-------
4.1
4. SOURCESOF VISIBLE EMISSIONS
4.1 INTRODUCTION
This chapter Is divided into two main sections. The first section
covers emissions from non-stack sources, for example, coke ovens and equip-
ment used for handling various kinds of materials. The second section
briefly outlines many of the sources that emit visible emissions from
stacks.
The chapter presents a review of most of the major sources of
visible emissions commonly encountered on field inspections. Because an
industry or a specific source has not been reviewed,this should not be
taken as an indication that the industry or source does not present a
problem as far as visible emissions axe concerned.
4.2 PROCEDURES FOR NON-STACK EMISSIONSOURCES
Many sources of emissions are common to several Industries, These
include, for example, roof monitors on buildings, crushers, conveyors,
screening operations, storage piles, etc. Other sources are specific to
any given industry such as coke ovens in the steel industry.
4.2.1 ROOF MONITORS
Many sources of visible emissions simply vent into the building,
particularly if there are a large number of small point sources, and the
emissions are allowed to escape into the atmosphere through an opening in
the roof.
Figure 4.1 Is a sketch of a roof monitor showing the emission points.
Evaluations should be made at the point of densest emissions, from a
position at ground level that is approximately perpendicular to the longer axis.
In connection with the current trend for tightening the existing air
pollution regulations, some agencies are not only observing the emissions
from the roof monitor, but are also making observations of individual
point sources from positions within the building. This procedure, however,
depends on strict interpretation of local definitions of "atmosphere".
This practice is not currently followed by EPA.
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4.2
EMISSIONS
Roof Monitor
Figure 4.1: ROOF MONITOR EMISSIONS
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4. 3
4.2.2 MATERIAL HANDLING OPERATIONS
Although the material may vary, the processes involved in the
handling of many diverse substances remain essentially similar. These
processes include drilling, crushing, conveying, screening and stockpiling
operations from the following industries:
- rock, sand and gravel handling
- dry concrete batching plants
- deep hopper grain unloading
- grain drying
- woodworking plants
- abrasive cleaning operations
- coal preparation plants
- fertilizer plants
- lime plants
— mining operations
4.2.2.1 DRILLING
Emissions from drilling operations are evaluated as they are re-
leased from the drilling device or the drill hole at a safe distance
(30-40 feet) from the drilling machine. See Figure 4.2a.
4.2.2.2 CRUSHING
Emissions are released as material is discharged from the primary
and secondary crushing machines. Observations should be performed at a
safe distance (e.g. 10-15 feet) from the discharge point, and at the same
elevation as the discharge, if possible. See Figure 4.2b.
4.2.2.3 CONVEYING
Visible emissions should be evaluated as material is discharged at
conveyor belt loading and transfer points. Evaluation should be made at
the same elevation as the discharge, if possible. See Figure 4.3a.
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4.4
Drilling Rig
EMISSIONS
Figure 4.2a: ROCK DRILLING EMISSIONS
Crusher
EMISSIONS
Conveyor
O
O
CT
"O"
Figure 4.2b: CRUSHING EMISSIONS
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4.5
EMISSIONS
EMISSIONS
i O
Conveyors
Hopper
EMISSIONS
Screen ,—•"-""""""'"
EMISSIONS
Figure 4.3a: CONVEYING-SCREENING MISSIONS
Conveyor
EMISSIONS
Figure 4.3b: STORAGE EMISSIONS
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4.6
4.2.2.4 SCREENING
Visible emissions should be evaluated as material is discharged
from the screen into the chute. The observer should maintain an obser-
vation point as close to the elevation of the screens as possible. See
Figure 4.3a.
4.2.2.5 STOCKPILING
Emissions occur as material is dumped from the conveyor onto the
storage pile. Observations should be made from ground level. See
Figure 4.3b.
Usually visible emissions from stockpiles are not performed and this
source may be governed by the fugitive emission regulation rather than the
opacity regulation. Emissions from stockpiles are a possible source to be
evaluated, however.
4.2.3 COKING OPERATIONS
These operations are found mostly in conjunction with the iron and
steel industry. Emissions of smoke and particulate matter occur during
charging and pushing operations, from leaks in the system and from storage
piles. Charging and pushing are generally the most serious problems.
4.2,3,1 CHARGING OPERATIONS
During charging, emissions emanate from:
a) charging holes
b) larry car hoppers
c) larry car control systems
d) standpipes
Figure 4.4 is a sketch of the top of a typical coke oven showing
these features. Emissions from these sources should be evaluated from a
position on top of the battery, in which case a respirator is essential.
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4.7
Larry Car
Hopper
Larry Car Control System
Standpipe Lid
Charging Hole
Figure 4,4: TOPSIDE VIEW OF COKE BATTERY
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4.8
4.2.3.2 PUSHING OPERATIONS
During pushing, the emissions are to be read while the door is in
the open position. Observations should be made from a ground level posi-
tion on the coke side of the battery, using the sky as the background.
Figure 4.5 shows a sketch of the ovens during the pushing operation.
4.2.33 DOOR LEAKAGE
Leakage can occur from both the leveler door and the coke oven door.
Emissions should be evaluated after the doors are closed and until emissions
diminish, from a ground level position, using the battery structure as
the background. Figure 4.6 is a sketch of the ovens with the doors closed.
4.2.3.4 STORAGE
When finished coke is stored in piles large quantities of windblown
dust can cause emission, as well as nuisance, problems.
REFERENCES:
1. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume II: Control Technology and
General Source Inspection. APTD-11Q1, Section 7.5. EPA
Office of Air Programs. 1972.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.2. EPA, Office of Air and Water Programs. 1973.
4.3 PROCEDURES FOR SPECIFIC STACK EMISSION SOURCES
4.3.1 POWER PLANTS, REFINERY HEATERS, BOILERS AMD MISCELLANEOUS
FUEL BURNING EQUIPMENT
This type of equipment generally only represents an opacity problem
while burning liquid or solid fuels without an adequate control system.
Fuel oils of greater than 0.5% sulfur content, coal and hogged fuel or
sawdust will usually creater opacities of greater than 20% and mostly in
the 30-50% range. As ash is formed, it clings to the tubes and is a
deterrent to efficient heat transfer. Hence, an operation called "soot-
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4.9
Door Removed
EMISSIONS
X i
r. • V
Quench Car
o
___J L..J _i~_.j__i
Coke
Door Removal
Machine
Figure A.5: VIEW OF OVENS FROM COKE SIDE DURING PUSHING OPERATIONS
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4 .10
All Doors Closed
M
Leveling Doors Closed
T"
Figure 4.6: VIEW OF OVENS FROM PUSH SIDE
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4,11
blowing" must be performed periodically to remove the ash deposit. This
is done with air or steam jets from retractable lances and the operation
tends to increase the opacity of the plume. If a detached plume exists,
this indicates that SO,, is reaching its dew-point at some small distance
downstream from the lip of the stack, and the plume must be evaluated at
the point that the acid mist plume becomes visible.
Orchard heaters for agricultural purposes are generally under a
separate category of regulation and are limited to an approved type of
equipment which can operate fairly cleanly. The old "smudge-pots" and
rubber tires for this purpose are no longer used.
Observations are to be made from ground level according to the usual
procedures for evaluating stack emissions.
REFERENCE:
Weisburd, M.I. Field Operations and Enforcement Manual for Air Pollution
Control. Volume II: Control Technology and General Source
Inspection. APTD-1101, Section 6.2. EPA, Office of Air
Programs. 1972.
4.3.2 REFINERIES
In addition to the numerous boilers and heaters in refineries, the
main sources of visible contaminants are: coking and coke-handling opera-
tions; catalyst regenerators and catalyst-handling equipment; incinerators
or flares as they are commonly called; brightening operations; hot asphalt
loading operations; asphalt air—blowing and grease-compounding.
Coking is usually done batch-wise in large vessels. During the
heating cycle the gases vent off into a closed system. At the end of the
cycle, the quench is made by filling the vessel with water. The vessel
is then opened to remove the coke, usually into a pit. If the quench was
not properly made or the level sensors malfunctioned, then heavy visible
emissions can be noted when the towers are opened. These emissions will
contain condensed water and must be evaluated with this in mind.
The coke is then crushed and conveyed to storage. If allowed to
become too dry, visible dust emissions may be a potential problem at
every operation and transfer point. The coke is then maintained in either
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4.12
covered storage or in open piles. In the latter case, it is again a poten-
tial problem in excessive winds.
To carry the situation further, the coke is then loaded into trucks
or rail transportation for transfer to a port and a shiploading operation.
Almost all of these handling operations present an emissions problem.
Catalyst regeneration for all the catalytic cracking and reforming
processes is performed to restore the catalyst activity by burning off
carbon and other contaminants deposited on the surface. Controlled tem-
perature and air rates provide the means. When the air is discharged it
contains a considerable amount of catalyst "fines" and even though the
kilns are generally constructed to allow the discharge of the flue gases
through dry type inertial dust collectors, a sufficient number of small
particles carry through to provide a severe opacity problem. Control
equipment such as an electrical precipitator is often added and many times
the discharge from these devices still represents a problem.
The catalyst handling facilities such as conveyor systems, etc.,
present the usual dust and opacity problems at all open transfer or
discharge points. Systems are varied in construction and operation and
must be evaluated during their operational cycle.
The three general types of flares for refinery waste gas disposal
are; Elevated flares, ground-level flares and burning pits. The opacity
problems occur when smoke is created by virtue of the combustion process
being incomplete. When there are inadequate heat values necessary to
obtain minimum theoretical combustion temperatures or an inadequate
supply of combustion air or an inadequate mixing of the air and fuel,
there will be hydrocarbon side reactions with the resultant production of
smoke. Steam jets are normally used to inspirate sufficient air and pro-
duce the turbulence required for good mixing and a smokeless flame.
Brightening operations is the broad term given to blowing a stream
of air through oil containing a slight amount of water dispersed through
it. The oil has a cloudy look and it loses sales appeal unless it is
"brightened". Thus any air stream discharging from equipment used for this
purpose generally contains in addition to the water vapor removed, a cer-
tain amount of entrained, finely divided oil droplets. This results in
an emissions problem unless some sort of filter or demister is used.
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4.13
When hot asphalt (normally at a temperature of about 400 F ) is
loaded into tank cars or trucks an emissions problem arises, if the
loading operation is not controlled. The surface of the asphalt is dis-
turbed and exposed to the air as it discharges from the loading spout.
The light ends escape as a visible vapor. Opacity readings can usually
be made at the loading opening of either the trucks or rail tank cars.
Grease compounding is a rather minor problem but emissions of
sufficient opacity to violate certain rules and regulations can be genera-
ted. As the temperature is increased, no appreciable emissions occur for
the first half of the cycle. At that time some emissions occur and when
a final quench is made by adding water at a temperature in the vicinity
of 400 F some oil mist droplets as well as condensed water vapor con-
stitute the elements of a fairly dense plume. The condensed water vapor
disappears and leaves a residual plume of oil vapor a short distance
downwind under normal conditions.
Observations can be made from gound level according to the usual
procedures for evaluating stack emissions.
REFERENCES;
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 579-698. EPA, Office of Air and Water Programs. 1973.
2. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries, APTD-1102, Section 7.6. EPA Office
of Air Programs. 1972.
4.3.3 RESIN KETTLES AND VARNISH COOKING KETTLES
Briefly described, this equipment most often is merely a large open-
topped kettle in which the ingredients for a polymerized resin or varnish
are heated and at certain points in the process, dry dusty ingredients
may be added. The chemical reactions taking place at elevated tempera-
tures can cause heavy visible emissions at times. Dumping of the dry
ingredients often is an opacity problem also.
Any convenient place from which the emissions can be observed is
suitable.
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4.14
REFERENCE:
Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 701-716. EPA, Office of Air and Water Programs. 1973.
4.3.4 SULFURIC ACIDMANUFACTURING
The only major opacity problem from this operation is the SO,, mist
that is emitted in the tail gas from the absorber. SO readily absorbs
the moisture that is present in the plume, forming droplets of sulfuric
acid. These droplets are in the submicronic size range and thus high
values for the opacity can occur.
Often the plume does not become visible until a few stack diameters
downwind, and this should not be confused with a detached steam plume.
Observations should be taken through the densest part of the plume,
which will not necessarily be at the plume exit.
The evaluation should be made from ground level.
REFERENCES:
1. Public Health Service. Atmospheric Emissions from Sulfuric Acid
Manufacturing Processes, U.S. Department of Health,
Education and Welfare. AP-13, 1965.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 716. EPA, Office of Air and Water Programs. 1973.
3. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.7. EPA, Office
of Air Programs. 1972.
4. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 5.17. EPA, Office of Air and Water Programs, 1973.
4.3,5 PHOSPHORIC ACID MANUFACTURING
The use of phosphoric acid, its salts and derivatives has enjoyed
a great increase in recent years. With the exception of fertilizers, most
phosphorous compounds are derived from orthophosphoric acid. Phosphorous
is burned to form the pentoxide which is reacted with water to form
the acid. Excess air is used to prevent formation of the trioxide. The
final stage of manufacture is the hydrator in which the pentoxide reacts
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4.16
and the crutcher.
Observations can be made in the usual manner.
REFERENCES;
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 737-749. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 5.15. EPA, Office of Air and Water Programs, 1973.
4.3.7 GLASS MANUFACTURING
Soda-lime glass constitutes about 90 percent of the total production
of commercial glass. It is produced on a massive scale in large, direct-
fired, continuous melting furnaces. Most other types are produced in small
batch furnaces and are a minor problem compared to soda-lime glass pro-
duction.
Silica sand, dry powders, granular oxides, carbonates, cullet
(broken recycled glass), and other raw materials are transferred from rail-
road hopper cars to storage bins. These materials are then batch-weighed
and blended in a mixer. The mixed batch is then conveyed to the feeders
attached to the sides of the furnace. A potential opacity problem exists
wherever the dust from these operations can be seen.
As the feeders supply the dry materials previously blended, they
float upon the molten glass in the furnace until they melt. Carbonates
decompose, releasing CO^ in the form of bubbles. Volatilized particulates,
composed mostly of alkali oxides and sulfates, are captured by the flame
and hot gases passing across the molten surface. The particulates that
do not settle out in the checkers are discharged out the stack and a visi-
ble white plume is formed.
The molten glass goes to the forming machines where the greases and
parting compounds create a visible emission which can be a very significant
source.
Observations are made in the usual manner.
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4.15
with water vapor to form the acid mist. The tail gas out of this vessel
is saturated with water and can produce a very dense plume. The concen-
tration of acid in the plume can be kept low with a well-designed plant.
However, even this small amount is effectively removed by an electrical
precipitator, a venturi scrubber or a Brink fiber mist eliminator.
Observations should be made from gound level in the usual manner,
bearing in mind that there is a strong possibility of a condensed water
vapor plume being present.
REFERENCES:
1. Public Health Service. Atmospheric Emissions from Wet-Process
Phosphoric Acid Manufacture. AP-57, U.S. Department of
Health, Education and Welfare, 1970.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p, 734-737. EPA, Office of Air and Water Programs. 1973.
3. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 5.11. EPA, Office of Air and Water Programs, 1973.
4.3.6 SOAP AND DETERGENT MANUFACTURE
In soap finishing operations dust can be emitted from equipment
performing the following operations: Addition of powdered and fine
crystalline materials to crutchers (mixers), mechanical sawing and cutting
of cold frame soap, milling and plodding soap, air-drying of soap in steam
heated dryers, forming and packaging. Emissions from these operations are
generally not extremely dense and may be marginal or very low key.
However, the grinding of soap chips, pneumatic conveying of powders, and
spray drying operations will generally cause emissions of excessive opaci-
ties.
The oleum or fuming sulfuric acid used in detergent manufacture
produces a dense mist when displaced vapors are allowed to escape into
the atmosphere. Thus, dense white 100% opacity emissions can be seen from
the vents of storage tanks and process vessels during filling operations
with oleum.
The receiving, storage and batching of the various dry ingredients
as well as pneumatic conveying, create dust and opacity problems. Dust
emissions occur during mixing and batching at the scale hoppers, mixers
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4.17
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 765-782. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.13. EPA, Office of Air and Water Programs, 1973.
4.3.8 FRIT SMELTERS
Ceramic coatings are water suspensions of ground frit and clay and
are used on glass, pottery or metal.
The frit is prepared by fusing various minerals in a smelter and then
quenching the molten material with air or water. The thermal shock
shatters the solidified material into small glass particles called "frit".
The frit is dried and put into a ball mill and ground with some other
materials. Ceramic slip is then prepared by suspending the ground frit
in a mixture of water and clay. The slip is applied to the metal or
glass or pottery surface and fired in a kiln.
Significant visible dust and fume emissions may or may not be
present depending on the batch composition. There most generally are some
visible emissions when charging. Other emissions come from condensed
metallic oxide fumes that have volatilized from the molten batch. They
often contain a mineral dust carryover in addition. Some glass fibers
are released and contribute to the opacity of the emissions.
Observations can be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 788-804. EPA, Office of Air and Water Programs. 1973.
2. EPA. ^Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.12. EPA, Office of Air and Water Programs, 1973.
4.3.9 FOOD PROCESSING
Food processing includes such operations as slaughtering, smoking,
drying, cooking, baking, frying, boiling, dehydrating, hydrogenating,
fermenting, distilling, curing, ripening, roasting, broiling, barbecuing,
canning, freezing, enriching and packaging. Obviously some produce large
volumes of visible contaminants and others only insignificant amounts. Two
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4.18
of the more troublesome operations will be discussed.
4.3.9.1 MEAT SMOKING
Smoke is normally generated from hardwood to provide a smoky
atmosphere for the purpose of partially cooking, curing and adding flavor
to ham, bacon, wieners, etc. A certain amount of the smoke is exhausted
continuously from both atmospheric and recirculating type smoke houses.
Unfortunately the particulates are in a submicron size range where light
scattering is maximum. These exhaust plumes can periodically be expected
to exceed 40% opacity.
4.3.9.2 FISH MEAL DRIERS
Excessive visible air contaminants can be created in fish meal
driers by the overheating of meal and volatilization of low-boiling oils
and other organic compounds. Smoke is more likely to be emitted from
direct-fired driers than from steam-tube units. Driers operated in the
200-300 F range of the gas discharge temperature can be expected to
produce a visible plume. Addition of certain low boiling materials to
drier feedstocks can also create visible emissions when there is essen-
tially no overheating of meal in the drier.
Observations for these sources may be im.de in the usual manner.
REFERENCES;
1. Public Health Service. Air Pollution in the Coffee Roasting Industry.
AP-9,U.S. Department of Health, Education and Welfare, 1964.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 788-812. EPA, Office of Air and Water Programs. 1973.
3. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
' Section 6.6, 6.7. EPA, Office of Air and Water Programs, 1973.
4.3.10 PAINTBAKING
Many systems for the application of protective or decorative coatings
on surfaces consist of a method for applying the coating. The coating is
then cured, or baked, into a hard finish in an oven. The ovens may be
batch or continuous; direct- or indirect-fired; resistance or infra-red
heating; etc. As the initial solvent or vehicle flashes off and the
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4.19
temperature increases, there is often a great deal of smoke produced.
Vent stacks in the roof and oven doors, or openings in the ovens of the
continuous type, are sources of visible emissions.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 865-871. EPA, Office of air and Water Programs. 1973.
4.3.11 INCINERATORS
There are numerous types of incinerators used to dispose of waste
material of one sort or another. Almost all present an opacity problem
unless they are properly designed with an additional combustion chamber
to incinerate the smoke. Both smoke and fly ash contribute to the opacity
of the visible emissions emanating from the incinerator stack.
Some of the more common names of incinerators used for various
purposes are as follows:
a. General-refuse
b. Mobile
c. Wood-waste
d. Flue-fed apartment
e. Pathological-waste
f. Brake-shoe debonder
g. Electrical winding reclaiming
h. Drum reclaiming
i. Wire burners
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 435-531. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 2.1, 2.2, 2.3. EPA, Office of Air and Water Programs, 1973.
3. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume II: Inspection Procedures for
Specific Industries. APTD-1101, Section 6.3 EPA, Office of
Air and Water Programs, 1972.
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4.20
4.3.12 HOT-MIX ASPHALT PAVING BATCH PLANTS
A typical hot-mix asphalt paving plant has the following components:
an oil- or gas-fired rotary drier, a. screening and classifying system,
weigh boxes for asphalt and aggregate, a mixer, and necessary conveying
and storage equipment.
Aggregate Is conveyed to the drier which heats it to 250-350 F.
This is then screened and classified and dumped into elevated storage
bins. Selected amounts of given sizes along with asphalt are weighed into
the mixer. The batch is then dumped into trucks.
Opacity problems arise from dust from the drier, conveying equipment,
screens and weigh hopper. Smoke comes from the mixing section. Trucks
are generally sprayed with a diesel oil to prevent sticking and as the hot
asphalt hits the diesel oil, it is vaporized into a bluish-white cloud
of considerable opacity.
Observations may be made in the usual manner.
REFERENCES;
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 325-333. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.1. EPA, Office of Air and Water Programs, 1973.
4.3.13 CONCRETE-BATCHING PLANTS
The aggregate generally arrives from the rock and gravel plant
along with sand in a sufficiently moist condition as not to be a problem.
The cement ,dust represents the main problem which can be emitted from the
receiving hopper, elevating equipment, and silo in the receiving and storage
system. Other points of emission are the weigh hopper, the gathering hopper
and the mixer. All cement-handling operatings may be considered in this
category.
Observations may be made in the usual manner.
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4.21
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 334-339. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.10. EPA, Office of Air and Water Programs, 1973.
4.3.14 STONE QUARRYING,ROCK ANDGRAVEL PLANTS
Rock and crushed stone products are loosened by drilling and
blasting and removed by heavy earth-moving equipment to the crushers.
Gravel from old dry beds is screened to obtain useable sizes, with
the oversize rock being crushed into various size ranges. A conveyor
system from the quarry carries the material into the plant proper. The
material passes through the first jaw crusher which is set to act on
rocks larger than 6 inches and to pass smaller sizes. The material is then
screened to get sizes smaller and larger than 1% to 2 inches. The under-
size goes to a screening plant and the oversize to another crushing plant.
This plant usually has several primary cone-crushers in parallel and several
more secondary cone-crushers also in parallel. The material is again
screened and goes to storage of the proper size.
As the material leaves the pit or quarry it is usually moist either
naturally or having been wetted down. Once crushing operations have
started, dry surfaces are exposed and dust emissions creating opacity pro-
blems begin. Then as the material moves to more screens and crushers, the
rock becomes more finely ground and the dust problem becomes greater.
All conveyor transfer points, screens, and crushers after the first
jaw crusher are potential sources of dust clouds with excessive opacity.
Observations should be made in accordance with the procedures out-
lined in Section 4.2, above.
REFERENCES:
1. Stern, A., Air Pollution, Volume 111. Academic Press, New York.
p. 123-127. 1968.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-AO,
p. 340-342. EPA, Office of Air and Water Programs. 1973.
3. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Sections 8.19, 8.20. EPA, Office of Air and Water Programs, 1973.
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4.22
4,3.15 MINERAL WOOL FURNACES
Mineral wool, known also as slagwool, rock wool, and glass wool,
is merely silicate fibers made in a cupola by using blast furnace slag,
silica, and coke (to serve as fuel). Its use is mainly for thermal and
acoustical insulation.
The major source of pollutants is the cupola or furnace stack.
The visible portion is mainly condensed fumes that have volatilized from
the molten charge. Heavy emissions can also be noted from the blowchamber
which consist of condensed fumes, oil vapors, binding agent aerosols, and
wool fibers. The curing oven may also have up to 70% opacity and the asphalt
applicator can smoke if the temperature of the holding pot exceeds 400 F.
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 342-350. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.16. EPA, Office of Air and Water Programs, 1973.
4.3.16 PERLITE-EXPANDING FURNACES
Perlite ore is surface-mined, or quarried, and is normally dried,
crushed, and screened at the mine.
A perlite plant for expansion of perlite, often referred to as
"bloated clay", consists of ore-unloading and storage facilities, a fur-
nace-feeding device, expanding furnace (rotary kiln), gas and product
cooling equipment, product classifying equipment and product collecting
equipment. Most of the opacity problems arise from leakage in the product
handling system and the outlet of the last product collector. Even when this
is a well-designed baghouse, the nature of the particles (sub-micron and
needle-like in shape) is such that they can penetrate the cloth filter and
evolve as an opacity problem.
Observations may be made in the usual manner.
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4.23
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual, AP-40,
p, 350-352. EPA, Office of Air and Water Programs, 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.17. EPA, Office of Air and Water Programs, 1973.
4.3.17 FEED AND GRAIN MILLS
This is strictly a mechanical problem of receiving, handling, storing,
size reduction, cleaning, and possibly bulk-loading from spouts. The
problems which occur are created mostly by dust. This is often controlled
for other reasons, mainly to reduce the possibility of explosions.
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 352-361. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 6.4. EPA, Office of Air and Water Programs, 1973.
4.3.18 PNEUMATIC CONVEYING AND DRYING
Almost all material handling by pneumatic conveying is accomplished
by new sophisticated, efficient equipment. However, occasionally something
happens to the air unlocking device (cyclone, etc.) and emissions occur in
the discharging air stream.
Driers can also be operated in myriads of processes without any
visible emissions other than water vapor. However, if the product being
b
dried is of an organic nature or otherwise capable of being decomposed,
scorched, burned, etc., there is always a possibility of an opacity problem.
All driers and their gases, either from the exit or entrance openings or
vent(s), should be scrutinized and analyzed for a possible emission of
visible contaminants.
Observations may be made in the usual manner.
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4.24
REFERENCE;
Los Angeles County APCD. Air Pollution Engineering Manual. AP-4Q,
p. 362-365. EPA, Office of Air and Water Programs. 1973.
4.3.19 WOODWORKING EQUIPMENT
Woodworking machines produce large quantities of waste sawdust,
chips, and shavings that must be removed from the work site. An exhaust
system is almost always used for this purpose and it almost always has
an unlocking or control device to remove the material from the plume.
However, at times this equipment can be somewhat inefficient on the smaller
particle sizes and a resultant visible plume occurs. Although the amount
of particulate may not be great, it should be remembered that there is
no simple correlation between weight of material emitted and the opacity
of the plume in which it is distributed.
Observations may be made in the usual manner.
REFERENCE:
Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 372-375. EPA, Office of Air and Water Programs. 1973.
4.3.20 ASPHALTROOFING FELT SATURATQRS
Asphalt saturators are machines used to Impregnate a moving web of
paper felt with hot asphalt by spraying and by dipping. The saturated
felt is converted into shingles by applying mineral granules while the
asphalt is in a soft condition, allowing the felt to cool and then cutting
to shape,
A very visible plume containing some moisture is generally exhausted
from the spraying and dipping area. The opacity is created by the con-
densed oil vapor from the hot asphalt. Some dust from the mineral handling
and loose fibers from the felt also contribute to the opacity.
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 378-390. EPA, Office of Air and Water Programs. 1973
-------
4.25
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.2. EPA, Office of Air and Water Programs, 1973.
4.3.21 ABRASIVE BLAST CLEANING
The applications of this type of cleaning are many and varied.
The type of abrasive can vary from sand, nutshells, and other light ma-
terials that break into dust easily, to all types of metals such as small
sharp pieces of steel wire or lead shot. The method of propelling these
onto a surface can be high pressure air or merely a centrifugal throwing
wheel or even an air and water jet. The nature of the surface also in-
fluences the amount of dust created. Surfaces covered with rust and scale
for example can have a great deal of finely divided material removed.
Blasting is often done in the open, but in populous areas an enclosure
housing the blasting operation is used. Unless controlled, the vents from
most enclosures will represent an opacity problem from time to time.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 397-401. EPA, Office of Air and Water Programs. 1973.
4.3.22 ZINC GALVANIZING EQUIPMENT
Zinc galvanizing is defined as the art of coating clean oxide-free
iron or steel with a thin layer of zinc by immersion into molten zinc
held at temperatures from 840°-860°F.
Opacity problems arise from this operation from a number of mechanisms.
If the metal has not been properly cleaned and degreased, an oil mist is
discharged when the article is dipped into the molten zinc. If the arti-
cles are not properly pickled and rinsed, more flux must be used to get the
desired coating. This creates more fumes. Whenever the flux cover is
disturbed or more flux added the fumes increase. Some zinc and zinc
chloride are to be found :'*i the fumes even though they are normally of
very low vapor pressure. it is thought that a wet article immersed in
the molten zinc will form steam that atomizes some zinc and flux into the
air. A dusting with finely ground sal ammoniac on the article immediately
after removal from the molten zinc is sometimes used to produce brighter,
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4. 26
smoother finishes. Although only small amounts of dusting fluxes are
used, dense fumes are always created.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 402-410. EPA, Office of Air and Water Programs, 1973.
4.3.23 CERAMIC SPRAYING AND METAL DEPOSITION EQUIPMENT
Ceramic sprays are slurries made up by suspending mixtures of feldspar,
quartz, clays, finely ground frit, pigments, etc. in water. When they are
sprayed onto metallic or pottery surfaces, the overspray can be emitted
through the vent in the spray booth. Although easily captured by a water-
wash control section they can be an opacity problem if not properly
controlled.
Metal deposition is accomplished by spraying molten metal onto a
surface to form a coating. Metallizing, thermal spraying or plasma arc
spraying all produce a discharge of clouds of molten metal fumes along with
finely divided oxide particles which are quite visible as emissions from
the spray booth vents. Attempts to control the emissions with a dry type
baffle or paint arrestor will result in remaining opacities in the
effluent which will be excessive.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 421-433. EPA, Office of Air and Water Programs. 1973.
4.3.24 STEEL MANUFACTURING PROCESSES
The two common steel-refining processes are: (1) The basic process,
wherein oxidation takes place in combination with a strong base such as lime;
and (2) the acid process, wherein oxidation takes place without the base
addition. These processes are usually carried out in the open hearth
furnace, the electric furnace, or the Bessemer converter. Electric furnaces
are of three types: direct-arc, indirect-arc and induction.
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4.27
Visible emissions are produced in the open hearth furnace throughout
the heat which lasts from 8-10 hours. A portion of the emissions is due
to the combustion of grease, oil and other contaminants in the scrap
along with the fuel, but most comes from the fumes or oxides of the
various metal constituents from which the alloy is being made. Much of
the emissions are submicronic in size which lends to their very good light-
scattering ability, producing plumes of high opacity.
The quantity and type of fumes emitted from an electric arc furnace
depend on several factors: Furnace size, type of scrap, composition and
cleanliness of the scrap, type of furnace process, order of charging
materials, melting rate, refining procedure, and tapping temperature.
Most of the emissions which are generated during the first half of the
heat, are either retained in the slag or discharged from the furnace vent.
Induction furnaces produce fumes with the same characteristics as
the electric-arc furnaces. They are generally smaller in size but the
opacity problem is just as great-
The Bessemer converters are not very common at present having been
supplanted by the open hearth and electric-arc furnaces.
It should be kept in mind that in addition to the furnaces, other
associated sources of emissions are the launder, ladles and molds during
tapping and pouring operations.
Observations should be made from a safe position using the usual
manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 239-255. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.5. EPA, Office of Air and Water Programs, 1973.
3. Weisburd, M.I, Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.4. EPA, Office
of Air Programs. 1972.
4. Public Health Service. Air Pollution Aspects of the Iron and Steel
Industry. AP-1. U.S. Department of Health, Education and
Welfare. 1963.
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4,28
4,3.25 IRON CASTING
The cupola, electric arc, and reverberatory furnaces are the types
mostly widely encountered. Dust and fumes, smoke, and oil vapor contribute
to the opacity problem. About 15% of the effluent is in the 1-3 micron
range. The dust in the discharge gases of the cupola comes from dirty
scrap and fines in the coke and limestone charge. Smoke and oil vapors
stem from partial combustion and distillation of oils from a greasy or
oily scrap charge. The other types are somewhat cleaner but may still
have an opacity problem from condensed metal fumes and dirty or oil scrap.
Observations may be made in the usual manner.
REFERENCES:
1. Public Health Service. Air Pollution Aspects of the Iron and Steel
Industry. AP-1. U.S. Department of Health, Education and
Welfare. 1963.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 256-269. EPA, Office of Air and Water Programs. 1973.
3. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.10. EPA, Office of Air and Water Programs, 1973.
4.3.26 SECONDARY BRASS- AND BRONZE-MELTING PROCESSES
Brass, an alloy of zinc and copper, and bronze, an alloy of copper
and tin are generally melted in reverberatory, electric-arc, induction, or
crucible-type furnaces. The visible emissions are comprised mostly of
dust and metallic fumes. The particle sizes of zinc oxide fumes vary from
0,03 to 0.3 microns. Lead oxide fumes, emitted from many brass alloys are
in this same size range. Consequently very opaque effluents may be expected
since the particles are in the 0.2-0.6 micron range producing a maximum
scattering of light.
Some of the factors causing large zinc fume concentrations are:
alloy composition, pouring temperature, type of furnace and poor foundry
practice.
Observations may be made in the usual manner.
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4. 29
REFERENCES:
1. Public Health Service. Air Pollution Aspects of Brass and Bronze
Smelting and Refining Industry. . AP-58. U.S. Department of
Health, Education and Welfare. 1969.
2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p . 269-283. EPA, Office of Air and Water Programs. 1973.
3. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.9. EPA, Office of Air and Water Programs, 1973,
4.3.27 SECONDARY ALUMINUM MELTING AND SMELTING
Thesa operations are essentially the remelting or re-refining of
aluminum. Accompanying these operations are: fluxing, alloying, degas-
sing and "demagging". The metal in the form of pigs, foundry returns
or scrap is melted in crucibles,induction furnaces or reverberatory fur-
naces. Much of the scrap charged to a reverberatory furnace is covered
with paint, dirt, oil, grease and other contaminants which create dense
fumes and smoke. Chemicals added during the accompanying operations noted
above create opacity problems also. The mean particle size given off
during fluxing, for example, is about 0.7 microns.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 283-292. EPA, Office of Air and Water Programs. 1973.
4.3.28 SECONDARY ZINC-MELTING PROCESSES
Zinc is melted in crucible, pot, kettle, reverberatory or electric-
induction furnaces as well as in retort and muffle furnaces. Muffle fur-
naces can also be used to manufacture zinc oxide by vaporizing and burning
the zinc in air.
The visible emissions from melting furnaces are generally caused by
excessive temperatures and melting of metal contaminated with organic
material. Fluxing can also create excessive emissions.
Zinc vapors escape from retort-type equipment when the residue is
removed and a new charge is put in. As the zinc vapors mix with air, dense
white zinc oxide fumes are formed. This operation can take up to one hour.
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4.30
The condenser portion is vented through a "speiss" hole and although the
emission rate is low, the opacity is high and goes on for 20 hours per
day.
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Mannual. AP-40,
p. 293-299. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.14. EPA, Office of Air and Water Programs, 1973.
3. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III. Inspection Procedures for
Specific Industries. APTD-1102, Section 7.8. EPA, Office
of Air Programs. 1972.
4.3.29 LEAD REFINING
For this operation the three principal types of furnaces used are:
The reverberatory, blast, and pot. Lead oxide is also produced by some
lead refiners by the Barton process. The pot furnaces create less problems
than either the reverberatory or the blast furnaces. All have the usual
problems of oxide formation, dirt and vaporized metal. The unagglomerated
particulate matter from secondary lead-smelting operations has been found
to be in a range of 0.07 to 0.4 microns with a mean of 0.3 microns.
The Barton process requires a baghouse for product collection of the
oxide, hence it normally does not represent a problem except for malfunc-
tion and leakages.
Observations may be made in the usual manner.
REFERENCES,:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 299-304. EPA, Office of Air and Water Programs. 1973.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.6. EPA, Office of Air and Water Programs, 1973.
3. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control, Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.8. EPA, Office
of Air Programs. 1972.
-------
4.31
4.3.30 METAL SEPARATION PROCESSES
This operation is also commonly known as "sweating" and can be
accomplished in rotary, reverberatory or muffle-type furnaces. The
material consisting of scrap or junk is charged to the furnace, and by
virtue of different melting points of the metals, the desired metal can
be made molten while the others remain solid by carefully controlling the
temperature.
This operation, as most metal-melting processes, is plagued by the
smoke from organic constituents as well as metal and metal oxide fumes.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 304-308. EPA, Office of Air and Water Programs. 1973,
A.3.31 FOUNDRY SAND-HANDLING EQUIPMENT
After the metal has cooled in the mold, the sand from the core is
generally recovered and mixed with fresh sand. The minimum equipment
required for reconditioning the old sand is a shake-out screen to remove
oversize particles, and a mixer-muller where clay and water are combined
with the sand to render it suitable for remolding. In addition, there ma}
be equipment for cooling, oversize crushing, fines removal, coating re-
moval and conveying. Emissions occur at any point where the dust from
sand breakdown can escape to the atmosphere.
Observations may be made in the usual manner.
REFERENCE:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40,
p. 315-319. EPA, Office of Air and Water Programs, 1973.
4,3.32 KRAFT PULP MILLS
This is the process most frequently employed in reducing wood to
cellulose fibers for paper manufacture. The largest source of visible
emissions is the recovery furnace, where the emissions include sodium
-------
4.32
sulfate, sodium carbonate, and carbon of 1 micron in diameter or less.
Other points that are potential sources of visible emissions include the
smelt tank, lime kiln, and hog fuel burning equipment which is used to
produce power.
Observations may be made in the usual manner.
REFERENCES:
1. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume II: Inspection Procedures for
Specific Industries. APTD-1101 Section 7.2. EPA, Office
of Air Programs. 1972.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42, Section
10.1. EPA, Office of Air and Water Programs, 1973,
4.3.33 CEMENT PLANTS
Virtually all of the processes involved in producing cement are
potential sources of visible emissions. These include: quarrying,
crushing, grinding, bagging, and material storage, although usually the
major source of emissions is the kiln. Normally there is some form of
control device on the kiln, but even so it is still a potential problem
as far as compliance with the opacity regulation is concerned.
Observations may be made in the usual manner.
REFERENCES:
1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40.
p. 335-340. EPA, Office of Air and Water Programs. 1973.
2. Weisbu^dj M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.10. EPA, Office
of Air Programs. 1972.
3- EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 8.6. EPA, Office of Air and Water Programs, 1973.
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4.33
4.3.34 ALUMINUM REDUCTION PLANTS
This activity is confined to the southeast portion of the United
States where the bauxite ore is mined. Imported ore is also processed
in areas where cheap power is available. The obvious visible emissions
come predominantly from the stacks of the anode plant and the potroom
air vents and roof monitors. Floor operations such as crushing and other
feed preparation operations may cause other emissions.
Observations may be made in the usual manner:
REFERENCES:
1. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.11. EPA, Office
of Air Programs. 1972.
2. EPA. Compilation of Air Pollutant Emission Factors. AP-42,
Section 7.1. EPA, Office of Air and Water Programs, 1973.
4.3.35 MINING
Open-pit mines and strip-mining produce large amounts of visible
emissions. Dusts, smoke and organic emissions are produced from surface
operations such as amassing spoil piles, loading and dumping, blasting
and transportation activities. Some mines will have greater emission
potentials than others, due to the type of mine and nature of the
deposits.
Observations should be made from safe vantage points as close to
the individual emission sources as is feasible,
REFERENCE:
1. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. Volume III: Inspection Procedures for
Specific Industries. APTD-1102, Section 7.12. EPA, Office
of Air Programs. 1972.
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5.1
5. PROBLEMS ASSOCIATED WITH CONDENSED WATER PLUMES
5.1 GENERAL
Plumes containing large amounts of water in the liquid form have
been variously described as "moist", "wet", "steam", "condensed water",
or "condensed water vapor" plumes. Usually they are referred to as
"steam plumes", which technically is not a correct term since steam is
defined as water in the gaseous phase. This term, however, has become
the generally accepted description of a plume containing droplets of
condensed water. As long as the temperature of the plume remains above
the dew point,—defined as the temperature at which water vapor just
begins to condense—the water remains in the gaseous phase and has no
effect on the opacity. In this context the plume is sometimes referred
to as being "dry".
Many sources of air pollution also emit large quantities of water
vapor. While water vapor itself is not normally classified as an air
pollutant, it can have adverse effects on the environment and can cause
problems to an inspector who wishes to make an opacity determination of
a source. In making the opacity determination of a source, the problem
occurs when the water vapor in the plume condenses, in which case the
effect of the water vapor cloud that is formed far exceeds the effect of
the particulate present in the plume.
Water vapor itself is invisible and thus has no effect on opacity,
but as soon as condensation occurs, the condensed water droplets scatter
light and affect the opacity. The droplets formed are in the submicronic
*
size range so that a relatively small mass concentration can have a large
effect on the plume opacity. Usually the effect is so great the the plume
is completely opaque and the opacity reading would be 100%. This is not
a valid reading however, since it reflects the opacity of the condensed
water vapor plume rather than the opacity of the pollutant plume.
Condensation of the moisture contained in the plume can occur within
the stack itself—when the steam plume is said to be "attached" to the
stack—or it can occur some distance downwind of the stack—in which case
-------
5.2
the steam plume is said to be "detached". In both cases the steam, plume
will eventually revaporlze as the plume is transported downwind. Whether
the plume will be attached or detached, and the distance taken for re-
vaporization to occur, depends upon the specifics of the case of interest:
plume temperature and moisture content, atmospheric pressure, temperature
and relatively humidity, and the degree of mixing between the hot effluent
gases and the ambient air.
5,2 SOURCESOF WATER VAPOR PLUMES
The largest water vapor plumes are produced from cooling ponds or
cooling towers which are not of direct concern to air pollution enforce-
ment officers, except from an esthetic point of view. These plumes can
cause fogging or icing problems over a considerable area, obstructing
visibility and creating a safety hazard to automotive traffic, aircraft
operations or shipping.
With the increasing public awareness and concern over the environ-
ment that has been occurring in recent years, air pollution agencies
appear to be receiving increasing numbers of complaints about air pollu-
tion emissions from the public. Many of these complaints, concern con-
densed water vapor plumes which are not covered by air pollution regula-
tions. The inspector must be able to tell at a glance whether the plume
contains condensed water vapor or not. This can be determined fairly
easily since a steam plume has a very wispy appearance and the opacity de-
creases rapidly from 100% to 0%. For a dry plume containing no condensed
moisture the opacity is seldom as high as 100%, except under upset condi-
tions, and the rate of change of opacity with distance is not so rapid.
The main effect of steam plumes is the possibility of masking the
presence of other pollutants in the plume.
Moisture in the plume may come from several sources, such as:
1) water produced by the combustion of fuels
2) from dryers
3) water introduced by scrubbers
4) water introduced to control the heat released by chemical reactions
5) water introduced to cool the flow before it enters an electro-
static precipitator.
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5.3
5.3 READING WATER VAPOR PLUMES
If the condensed water vapor plume is detached, opacity determina-
tions can be made immediately at 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
readings will become, which of course, tends to act in the 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 5.5 in conjunction with estimates of meteorological
and effluent conditions, and a few minutes of computation, will allow the
inspector to 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.
5.4 DESCRIPTION OF THE PSYCHROMETRIC CHART
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 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.
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5.4
3) Relative humidity, which is the ratio of the partial pressure
to the saturation vapor pressure of water, at the same
temperature.
4) Humidity ratio, which is the ratio of the mass of water
vapor present per unit mass of dry air.
5} 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 5.1 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
100 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; 1) Toward the lower end of the ambient temperature
range it takes very little 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; 2) The possibility of a
steam plume being formed is smallest on hot, dry days.
5.5 EXAMPLE OF THE USE OF THE PSYCHROMETRIC CHART
The psychrometric chart shown in Figure 5,1 may be used to deter-
mine 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.)S a value for the humidity ratio
may be obtained from the following expression;
-------
— 0,1*
PSYCHROMETR1C CHART
Boromslric Preiiwre 2?.92 tnclsci ol Mercury
n !ii !/i lii/H \f\ d/j-i i /Is HH/tr^^i/ i tin i
R-filJ; /; Al /r; iK'oi r /u! i'/; .! • ;Tr4iJ I i n
5j^oip-'-, _-f:: L -t;:^:-y<\.\f*K-L
?0^J^t;^^i4£S
-j»*^>
-------
5.6
Humidity Ratio «= 4354 (M.CJ Grains
1- M.C. Lb of Dry Air
which follows from the Ideal Gas Law and the definitions 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
Effluent Gas
Exhaust Temperature (Dry Bulb) = 160°F
Moisture Content = 16.8%
Substituting these values into the expression for the humidity
ratio gives:
Humidity Ratio = 4354 (Q.168)
1-0,168
= 880 Grains
Lb. of dry air
The state point of the ambient air is at the intersection 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 5.2 shows the two state points plotted on the psychrometrie
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,
-------
PSYCHROMETRIC CHART
Borometric Pressure 29.92 Inchei of Mercury
•g^^'Ij; "j^^y^l^fl:^^^ p. i i.y|riCi|T;.jt.; r.t-TFrfs4.jH't i-j I J^-i l-r;"^;:^ i •-''•i' j I '- ij^rr-^iU ^t!
tO SO «0 SO «0 TO, 80 W 100 IIO 120
WO ISO 160 170 180 190 200 2IO 2ZO 250 Z40 Z50 260 270 £30 2SO 300 S!0. JZO 3SO
OBV BULB TEMPEH«TUHE-*F
Buffalo Forge Company
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5.
5.6 BIBLIOGRAPHY
1. Buffalo Forge Company. Fan Engineering. 1970.
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.
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. Pollu-
tion Engineering, March 1972.
8. Rohr, F.W. Suppressing Scrubber Steam Plume. Pollution Engineering,
November 1969.
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6.1
6. LEGAL ASPECTS OF OPACITY OBSERVATIONS
6.1 SUMMARY
Most people are under the impression that "air pollution" and more
particularly, the laws that have been passed to control it, are of rather
recent origin. As a matter of fact, in the year 1273 during the reign
of Edward I, the first smoke abatement statute was enacted. This law pro-
hibited the use of coal as detrimental to health, and in 1307 one offender
was condemned and executed.
Although present-day punishment for violators is not nearly so
drastic, the original concept of the nuisance category has been accepted,
enlarged upon, and developed into the modern laws. These laws have been
tested in most State Supreme Courts, as well as the United States Supreme
Court, and have been upheld as legal, proper, and constitutional in the
control of excessive visible emissions.
Most of the current laws have been developed since the turn of the
century. However, Kennedy, (1957), in a 50-year review paper, has
summarized the accomplishments of the pre-1907 period. He states that
"the following aspects of air pollution control law represent the majority,
if not all, of the basic principles which became settled and accepted:
(1) Although at common law, smoke and other air contaminants
were not considered to be a nuisance "per se" the legis-
lature can declare air contaminants to be a public nuisance
and the courts will not invalidate such legislative acts,
provided that the legislative declaration is reasonably
clear and certain,
(2) A statute or ordinance will be valid as far as due pro-
. cess is concerned, if it is reasonably necessary for the
benefit of the public welfare, and if it is not arbitrary
or oppressive,
(3) The state has the power to confer upon municipalities the
power to enact ordinances for the purpose of regulating air
pollution as constituting a propep exercise of the police
power of the municipality.
(4) The courts take judicial notice that dense smoke is a
nuisance or at least harmful enough to be declared a
nuisance."
Kennedy states further: Generally speaking, the law of air pollu-
tion has seen these major developments since 1907.
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6.2
(1) The doctrine of nuisance has followed in the course of
urban and industrial development.
(2) The control of air contamination by the use of strict
statutory and administrative regulations has become
quite popular.
(3) The courts have adhered fairly rigidly to the letter of
the new police regulations. The way of the transgressor
has become increasingly difficult."
6.2 LEGAL STAMPING OF OPACITY OBSERVATIONS
Various courts in the country have found that:
(1) The opacity of emissions may be ascertained according to
a definite scientific scale, such as the Ringelmann chart.
(2) Inspectors can be trained to read the opacity of emissions
of any color. It is not necessary for them to have a
Ringelmann chart, or any other aid, with them in the field
at the time observations are made.
(3) The Ringelmann chart has been accepted into court as
evidence.
(4) It is not unconstitutional to force a source to curtail
its emissions in order to conform to the air pollution
regulations, no matter what the cost may be to the source.
The source may even be forced to close down if the regu-
lations cannot be complied with.
(5) Officers of a corporation may be held responsible for
actions performed by the corporation. An officer is not
responsible for these actions, however, if he had no control
over the actions,
(6) Certain operations may be exempt from the regulations.
(7) Regulations may be allowed to vary with locations depending
upon the local problems and conditions.
(8) Evaluation of the opacity of the emissions may be made from
either inside or outside the plant property. Advance notices
or search warrants are not necessary.
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6.3
6.3 SUMMARY OF COURT CASES
The following are summaries of some specific court cases that have
given legal standing to the items listed above.
CASE 1. AIR POLLUTION VARIANCE BOARD OF COLORADO VS. WESTERN ALFALFA
CORPORATION, U.S. SUPREME COURT, No. 73-690. (MAY 20, 1974)
The Air Pollution Variance Board of the State of Colorado challenged
the Colorado Court of Appeals decision (No. 71-494, 1973, 510 P. 2d 907)
that an evaluation of the opacity of visible emissions from an observation
site on company property, and which was made without notifying the company,
constituted an unreasonable search and lacked the fundamental elements of
due process of law.
The Board then appealed this decision to the U.S. Supreme Court which
ruled unanimously that State authorities are free to make unannounced in-
spections on the property of suspected air polluters and neither a search
warrant nor advance notice is required for inspections. Justice Douglas,
in his opinion, also stated that no search warrant is needed for "sights
seen in open fields." The court determined that, depending on the layout
of each plant, the inspection can be made from locations inside or outside
company premises, in order to be able to make an evaluation from a suit-
able observation point.
CASE 2: NORTHWESTERN LAUNDRY VS. DBS MOINES, 239 U.S. 486, 365, ct. 206,
60 L.ed. 396, Des Moines, Iowa (1916)
This is a very important early case in the history of air pollution
laws. The court decided that:
1. The Des Moines ordinance declaring the emission of dense smoke
to be a public nuisance was constitutional.
2. The Ringelmann Smoke Chart represented a valid method of
measuring the opacity of emissions.
3. There are no constitutional objections to the regulations,
even though the company may be forced to spend a considerable
amount of money in order to comply with the regulations, or
close down if compliance could not be achieved.
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6.4
CASE 3; BOARD OF HEALTH OF WEEHAWKEN TOWNSHIP, HUDSON COUNTY VS. NEW
YORK CENTRAL RAILROAD 4 N.J. 293, 72 A 2d (1950)
The court said: "...There are no constitutional restraints upon
state actions against the emissions of dense smoke injurious to tbe common
welfare; the only requirement is that the regulation be free from ar-
bitrariness. Northwestern Laundry Co. vs.DesMgines supra."
CASE 4: CINCINNATI VS. BURKHARDT, 30 OHIO CIR. CT. REP. 350, ANN. CAS.,
1918 B, 174. Cincinnati, Ohio- (1908)
An ordinance which provided for the measurement of the density of
smoke by use of a color scale was upheld.
CASE 5: CITY OF ROCHESTER VS. MACAULAY-FIEN MILL COMPANY, 199 N.Y. 207,
92 N.E. 641, 32 L.R.A. (N.S.). 554, Rochester, N.Y. (1910)
The court held reasonable an ordinance of the City of Rochester which
provided for the adoption of the standard of the Ringelmann Scale,
prohibited dense smoke during the day, except from between 5 a.m. and
7:30 a.m., and which permitted the emission of dense smoke for 5 minutes in
every 4 consecutive hours.
CASE 6: PEOPLE VS. INTERNATIONAL STEEL CORPORATION 102 CAL. APP. 2ND
SUPP. 935, 226 p. 2d 587, Los Angeles, California. (1951)
The Appellate Department of the Los Angeles County Superior Court
approved the use of the Ringelmann Chart for measuring the opacity of
visible emissions, and asserted that inspectors trained in the use of the
chart may be classified as experts and may testify as such to the Ringel-
mann number of a particular smoke emission, without using an actual chart
during the evaluation.
CASE 7: PEOPLE VS. INTERNATIONAL STEEL CORPORATION ET AL., CR A 2654
Los Angeles, California,(1951)
The defendants claimed that the California opacity regulation
was unconstitutional in that a distinction between permission and pro-
hibition, as far as opacity is concerned cannot be drawnj or if such
a distinction can be drawn, it is drawn in the wrong place. They
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6.5
further claimed that the opacity regulation does not apply to certain
agricultural operations or orchard heaters which they claimed prevents the
law from having a uniform operation, making the law arbitrary in its
application. The court disallowed all the above claims.
Three witnesses testified regarding the opacity of the smoke being
discharged from the defendants' place of business. The defendants claimed
that the witnesses showed no qualifications sufficient to enable them to
give expert testimony on the subject, and that their observations were not
sufficient because they had no Ringelmann chart with them at the time the
observations were made. The court ruled that the witnesses were qualified
to testify as expert witnesses and that a Ringelmann chart was not necessary
since they had all been certified as "smoke readers" without the use of the
Ringelmann chart at a school given by the Los Angeles County Air Pollution
Control District.
The court upheld the conviction against one of the officers of the
corporation since the court decided that he was in charge of the operation.
The court dismissed the charges against the other officer of the corporation,
since it decided that although he knew of the operations he did not have
any control over them.
CASE 8: PEOPLE VS. SOUTHERN PACIFIC COMPANY, ETC., CR A 3585 TRIAL COURT
NO. 57288, Los Angeles, California. (1957).
This case concerned a fire that burned for several hours and the
opacity of the smoke from this fire exceeded the regulation limit. It
was not clear how the fire was started, but an employee of the company
was aware of the fire and made no effort to extinguish it. The court held
that the company was responsible for the fire and therefore was liable in
the same manner as the one who started the fire.
CASE 9: PEOPLE VS. FRANK BABCOCK, CR A 3676, Los Angeles, California.
(1957)
The defendant was the owner and operator of several apartment and
hotel buildings in the Los Angeles area and was charged with two counts
of emitting smoke from boilers in these buildings. It was his contention,
on appeal of being gound guilty, that the statute was unconstitutional in
that in San Francisco where there Is also an Air Pollution Control District
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6,6
the violation would not have been a criminal offense, whereas in Los
Angeles the same act would have been. He contended that there was unequal
classification, therefore the statute was unconstitutional. The People's
contention, on appeal, was that there was a reasonable classification in
that in different localities there were different smog conditions, differ-
ent problems, and therefore, different regulations. The court dismissed
the defendant's claims.
CASE 10: PEOPLE VS. METROPOLITAN STEVEDORE COMPANY, CR A 3562,
Long Beach, California (1957)
The defendants operated a bulk loader in such a manner that cargo
being loaded into the hold of a ship emitted dust of an opacity darker
than the regulation limit. They contended that: (.1) Application of the
opacity regulation to the bulk loader constituted an unlawful burden on
foreign commerce, (2) the opacity regulation was not applicable to opera-
tions made pursuant to its contract, and (3) the evidence was insufficient
to support the judgment. The court dismissed all of the defendants' claims,
CASE 11: ESSEX CHEMICAL CORPORATION, ET AL, VS. RUCKELSHAUS,U.S. APP. D.C.
486 F2d 427. (SEPTEMBER 10, 1973)
The 10% opacity standard for sulfuric acid plants, and the 20%
opacity standard for coal-fired steam generators, were challenged on
grounds identical to the Portland Cement Association case discussed below
i.e. the standard Is arbitrary and opacity determinations cannot be made
with sufficient accuracy at these low opacity values.
This case was also remanded, and at the time of publication of this
manual the case has not yet been reheard.
CASE 12; STATE VS. FRY ROOFING COMPANY, OREGON COURT OF APPEALS, 495 P.
2d 751. (1973)
The circuit court had found Fry Roofing Company guilty of violating
the Oregon opacity regulation. The Oregon Court of Appeals found that the
regulation limiting emissions that are greater than 40% opacity to three
minutes in any hour was constitutional. The Appeals Court also ruled that
the original judges had not abused their authority by admitting the testi-
mony of inspectors with only two day's training in the evaluation of
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6.7
visible emissions who had been recertified shortly before making the
evaluation.
CASE 13: PORTLAND CEMENT ASSOCIATION VS. RUCKELSHAUS 486 F 2d 375,
U.S. COURT OF APPEALS, DISTRICT COLUMBIA CIRCUIT (JUNE
29, 1973)
EPA's response to the "unreliability" challenge to Section 111 opacity
standards was held sufficient justification for such regulations to measure
pollution and to aid in control of emissions, and were therefore validated on
remand by the Court in PortlandCement Association vs.Train, Administrator,
No. 72-1073 B.C. Cir. May 22, 1975. While this validation of opacity regu-
lations is binding only for Section 111 purposes, it will serve as valuable
precedent for challenge to opacity standards within the State Implementation
Plans.
CASE 14: NATIONAL ASPHALT PAVEMENT ASSOCIATION VS. TRAIN, U.S. APP.
D.C. - NO. 74-1332 (1975)
This case deals with opacity issues similar to those contained in
Case #13, and will be heard by the Court in the fall of 1975.
CASE 15: STATE OF NEW JERSEY VS. FRY ROOFING Docket No. C-3682-72
New Jersey Superior Court, Trenton, New Jersey. (1974)
Fry Roofing contended that the procedures for determining opacity
"!)....were scientifically inaccurate in that they were simply estimates
obtained by the unaided eyes of field observers, and that the investiga-
tors did not distinguish visible water vapor from the particulate plume;
and 2) that the investigations were conducted without a warrant, without
notice to and without consent of the defendant, constituting unreasonable
searches in violation of the Fourth and Fourteenth Amendments to the U.S.
Constitution,"
Violations of the opacity regulation were observed on two separate
occasions; once from a location on company property and once from off
company property. For both cases the company contended that the visual
inspections violated the Fourth Amendment to the U.S. Constitution.
Citing the Air Pollution Variance Board of the State of Colorado vs.
Western Alfalfa Corporation (Case 1, above), the court concluded that the
company's constitutional rights had not been violated.
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6,8
The company contended that the observations were made without prior
warning, violating the right of due process under the law. The court
concluded that no prior warning is necessary.
The company also contended that the observers' training was inade-
quate since they had not received any training in the evaluation of plumes
containing visible water vapor. Evidence was introduced to demonstrate
that it is not difficult to determine if a steam plume is present and the
observers testified that a "steam plume" had not been present. Using
representative data for the stack exit conditions and actual meteorological
observations, the witnesses demonstrated by use of a psychrometric chart
that a steam plume would not be formed. The court concluded that the
observers were fully qualified and the court was satisfied that there
was no steam plume present at the time the observations were made,
The case was remanded, and at the time of publication of this manual
the case had not reached the courts.
6.4 PRESENTATION OF TESTIMONY
6.4.1 GENERAL
Whether the case is to be heard before an administrative body or in
a regular court of law, the witness must be prepared to properly convey
to a board, jury, or judge his competency to testify, and his credibility
as an evaluator of visible emissions.
The witness must have had adequate and proficient training as a result
of attending a smoke-reading school operated in the manner prescribed in
EPA Method 9 and from which he has received a certificate. He should be
familiar with moisture laden plumes and understand how to evaluate them.
He must be able to evaluate weather conditions by visual observations and
with simple measuring devices.
The witness should have some familiarity with courtroom procedures.
This can be acquired by attending actual trials or by participating in
mock trials. He should be familiar with all aspects of the law that
pertain to his responsibilities.
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6.9
Given his expertise and knowledge of the case under review, the
attitude of the witness is crucial to the effectiveness and acceptability
of his testimony. His objective should be to provide accurate and complete
facts in as clear a manner as possible in response to direct questions.
He should not offer his opinions and judgments of the source being tried
or of official programs or policies, nor should he be concerned with
justifying his infallibility as an expert in his field. He should not
argue with or "talk down" to the examiner, or give the impression that
he is an expert in a specialized area when he is not. He should avoid
exaggeration of the facts and boasting of his accomplishments.
The witness should be prepared for the proceeding. He should know
the exact substance of what he will be called upon to testify. He should
be rested and alert. Fatigue can affect concentration and the precision
of answers to a marked degree. He should be able to quickly think through
his answers before responding, and avoid saying anything that he does not
mean.
6.4.2 WITNESS BEHAVIOR
Personal appearance in the courtroom is quite important. The witness
should come to the courtroom in conservative dress (preferably a business
suit, or in uniform, if applicable). He should be well-groomed with
neatly trimmed hair. The witness should always arrive on time or a little
ahead of time so as not to hold up the proceedings. In general the wit-
ness should avoid any behavior that might tend to create an unfavorable
impression in the mind of the court.
When called to the stand, the witness should walk with assurance.
When being sworn in, he should hold his right hand high with fingers
extended and look directly at the person administering the oath. After
the oath has been administered he should say "I do" in a loud voice, and
generally behave in a confident manner.
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6.10
6.4-3 TESTIMONY
The two main categories of witness testimony Is the direct examina-
tion by his own counsel and the cross-examination by the opposing counsel.
The direct examination is usually started with a line of questioning which
will provide a foundation for the qualifications of the witness. The
following list of questions which will be asked by the agency counsel will
give some idea of how this is achieved:
1. State your full name and home address, please.
2. By whom are you employed?
3. How long?
4. Prior to your employment with (agency or company), did you have any
college or university work? What kind of work? Graduate work? Degree?
5. Have you had any prior employment which might be relevant to this case?
6. Have you ever attended a training course which might be referred to
as "Smoke School" or "Smoke-reading School"? When? Were you certified?
7. Describe briefly the training you received.
8. Did you learn to evaluate black smoke?
9, Did you learn to evaluate any color other than black?
10. Did you learn to e\'aluate emissions without the use of the Ringelmann
Chart?
11. Were you required to attain a certain degree of proficiency before
being certified?
12. What were the standards?
13. Do you recall your own personal proficiency?
14. Have you testified in court before as an expert?
The foundation of the case is then laid with questions similar to the
following:
1. On date and location, were you on duty as a representative of (agency
or company)?
2. What directed your attention to this location? (Routine observation,
citizen's complaint, etc.)
3, Where were you when you first saw It?
4. Could you determine the source of emission?
5. Describe the premises.
6. Did you make any readings. What time did they begin? What time
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6.11
did they end? What were the times, duration and densities of the
emissions?
7. Did you see the source of the emissions?
8. Were any representatives of the defendant present and were there any
conversations?
These are the types of questions that will be asked by the counsel in
order to present the case to the court. The witness may use notes including
the observation and summary forms, he has personally made in order to refresh
his memory on any facts, but may not read from them directly. The answers
to the questions should not be memorized but they should be accurate, factual
and truthful.
After the direct examination is finished, the opposing counsel will
cross-examine the witness. In this phase, he may try to discredit the
witness, or present conflicting technological evidence. The witness must
be knowledgeable in his field and be prepared to respond to such questions.
Re-direct examination by the witness' counsel may be necessary to
rebut some points brought up in the cross-examination. Opposing counsel
may then want to make an additional refutation. This type of questioning
could go on indefinitely except that it will usually be terminated by the
judge when he feels it is no longer useful to the trial.
For some administrative type hearings direct testimony is written out
in narrative form and only the cross-examination is done orally. The
opposition is usually given a week or two to study the document before the
witness appears. This document usually consists of four parts: (a) his
qualifications as an expert, (b) the material from which he fashions his
opinion, (c) the reasoning process used to arrive at an opinion from the
material, and (d) the conclusion or opinion itself.
Other cases involve discovery or the process by which one side finds
out what the factual basis for the other side is. This may be done by de-
position or interrogatories. For a deposition the potential witness is
placed under oath before a court reporter and asked a wide range of ques-
tions designed to prepare the opposing lawyer for his testimony at the
trial. The interrogatories are merely written questions served upon the
opposition which are to be answered under oath.
In any case, the witness must eventually appear in court to present
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6.12
his testimony. Some guidelines for this presentation are given below.
If at all possible, the witness should be on hand to view the pro-
ceedings prior to his testimony. This will give him the "tone" of the
hearing and indicate in general what type of questions to expect. Most
importantly, it will reassure him.
6.4.4 TYPE OF INFORMATIONREQUIRED INTESTIMONY
The witness may be called upon to present any information that he
may have that will be necessary to prove a violation. These tend to fall
into two categories:
1. Basic elements
a. The rule or state code section violated.
b. The date and location of the violation.
c. The time or times of violation.
d. The time, duration, and densities of the violating
opacities.
e. The names and titles of the owners and operators of
the equipment emitting the violating opacities.
f. The names of the enforcement officers observing the
violation (usually the witness).
2. Supportive elements
a. Identity of visible emissions, i.e. "smoke" "fume" "dust"
etc.
b. Description of the equipment and process or processes with
their operating cycles.
c. Ambient atmospheric conditions.
1. Light conditions and sun position.
2. Wind direction and velocity..
3. Temperature and relative humidity.
d. Background against which observation was made.
e. Position of observer relative to point of emission; the
height of the stack and his distance from it.
f. Description of surrounding geographic features such as
buildings and streets.
g. Certification date of the observer.
h. Description of plume appearance, i.e. color, length,
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6.13
moisture, etc.
While on the stand the witness should always be truthful, fair and
frank. Before replying to a question the witness should pause for a while
in order to collect his thoughts. A hasty answer may not convey the full
facts that should be brought out and an incomplete, or erroneous, reply
might place the opposing counsel in a position to discredit the witness,
which in turn could seriously jeopardize the case.
Answers should be brief and to the point. Information should never
be volunteered—the reply should merely be an answer to the question asked.
If an objective is raised the witness should stop speaking at once, and
not continue until the court has given its ruling. If the opposing attor-
ney interrupts an answer this should be indicated to the presiding judge.
The skillful witness also knows when to concede a point, even if it reflects
poorly on his work.
The witness should express himself as lucidly as possible, using
simple technical language that the judge, jury and attorneys can understand.
The court should not be treated in.a condescending manner, however.
Mannerisms, witicisms and colloquialisms should be held to a minimum, and
no attempt should be made to overimpress the court with irrelevant infor-
mation.
For the court reporters' benefit, the witness should speak loudly,
clearly and slowly, waiting until the question has been completed before
beginning the answer. Replies should not be made by a movement of the head
to imply a "yes" or "no" answer, since the court reporter may not always
be looking at the witness.
When addressing the court, use "Your Honor"; when addressing the
attorneys, use their names.
The witness should never lose his composure by becoming flustered or
losing his temper, especially when being goaded or aroused by the opposing
counsel. The witness also has no obligation to answer a question which he
does not feel qualified to answer. An "I am not qualified to answer that"
is perfectly acceptable.
If the witness has made a mistake, or a contradictory statement, this
should be admitted and corrected. Under no circumstances should any attempt
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6.14
be made to cover up the error, since it is almost inevitable that the
true facts will eventually emerge, throwing the witness' credibility into
a very poor light.
During recesses the witness should not discuss anything with other
witnesses or parties to the case, and should only speak with his own coun-
sel.
The witness should not allow the opposing counsel to suggest facts
or an opinion. Under no circumstances should the counsel be engaged in an
argument. An answer to a question which is identical to a previous ques-
tion should be restated as given the first time. Additional statements can
be given, however, to help clarify the original statement, if this Is
indicated by the line of questioning.
6.5 BIBLIOGRAPHY
1. Cantor, B.J. The Expert Witness, ABAJ, 52, 946-948. October 1966.
2. Conner, W.D. and Hodkinson, J.R., Optical Properties and Visual Effects
of Smoke Stack Plumes, DREW, PHS Publication No. 999-AP-30, 1967,
3. Hammon, S. The Lawyer and the Expert, ABAJ, 54, 583-585, June 1968.
4. Health, Education and Welfare (Department of), A Compilation of Selected
Air Pollution Emission Control Regulations and Ordinances, PHS,
Publication No. 999-AP-43, 1968.
5. Horsley, J,E. How to Prepare Yourself for Cross-Examination, Journal
of Legal Medicine, Vo. 2, No. 1, pp. 26-28. 1974.
6. Kennedy, H.W. Legal Support for Los Angeles' Strict Air Pollution
Program. Report to Los Angeles County Board of Supervisors. 1957.
7. Nickerson, The Expert Technical Witness on Trial, ABAJ, 50, 731, August
1964,
8- Norman, J., How to be a Witness. Program Guidelines and Information
Branch, EPA. 1972.
9. Rodgers, J.A., A Primer for EPA Employees: Presenting Scientific
Evidence, Paper from office of General Counsel. 1974,
10. Weisburd, M.I. (Editor), The Law of Air Pollution Control, Air Pollu-
tion Control Field Operations Manual, PHS Publication No. 937,
1962.
11. Weisburd, M.I. Field Operations and Enforcement Manual for Air
Pollution Control. APTD-110Q, EPA. 1972.
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7.1
7. EFFECTS OF VIEWING CONDITIONS ON OPACITY READINGS
7.1 WINDSPEED
The stronger the wind speed the more the plume will be diluted,
thus reducing the opacity. However, a small finite time "must elapse
before the plume can mix significantly with the ambient air, with the
result that the plume opacity at the emission point is not affected by
wind speed to any great extent.
Read at stack exit, or the source point.
7.2 WIND DIRECTION
If the plume is being blown directly toward or away from the
observer, the observer tends to read through a longer path length than
when readings are taken with the wind blowing perpendicularly to the
observer's line of sight. The longer the path length through the plume,
the greater the plume opacity will appear.
Difficulties in obtaining good readings, especially for low-level
sources, can be experienced under light, variable wind conditions. (This
is most likely to occur on hot, sunny afternoons). Wind direction can
vary considerably within a very short period of time (360 in less than
a minute, for example) with the result that the observer can find himself
in a poor position for taking opacity readings at the specified 1.5- or
30- second time intervals. Under variable wind conditions the observer
should watch the plume more or less continually and take readings when the
plume is being blown at right angles to the observer's line of sight.
(The observer can change the observation point should the mean wind
direction change, provided that the sun remains in the proper orientation.
Any changes in the observer's location must be indicated on the observation
summary form).
Read at rightangles to the wind direction.
7.3 VIEWING POINT
As the plume is transported downwind diffusion takes place, reducing
the concentration of the effluent and thus reducing the opacity.
An exception to this may occur in the case of an acid mist plume
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7,2
where the greatest opacity can occur a small distance from the stack exit.
This is caused by the hygroscopic acid mist particles growing in size by
absorbing water vapor as they are t-..^ r.jrted downwind.
Always read at the point of maximum opacity. For a part.iculate plume
this will be at the stack exit but for an acid mist plume it can be some
distance downstream. (Indicate on the observation form where the viewing
point is in relation to the stack exit or source point).
7,4 ILLUMINATION
Contrast between the plume and the background will increase with in-
creasing illumination, causing the apparent opacity to increase.
Attempt to take readings with good lighting conditions.
7.5 BACKGROUND
Tests conducted by Hamil, et. al., (1975) indicated that the back-
ground used to evaluate the opacity of an emission does have an effect on
the observed opacity. Hamil presented data showing that for white smoke
the inspectors' readings tended to have a negative bias (i.e. they read
low) whenever a non-contrasting background (overcast sky) was used. When
a contrasting background (blue sky) was used, the inspectors tended to
have a slight positive bias (i.e. they read high) for very low opacities
(15% opacity, or lower) and they tended to read low in the 20% to 35%
opacity range.
Whenever possible black plumes should be evaluated using blue sky
as background and white plumes should be evaluated using a dark background,
such as buildings or hills. Evaluating plumes against a non-contrasting
background tends to reduce the observed opacity.
A contrasting backgroundshould be used if possible.
7,6 ATMOSPHERIC STABILITY
A plume disperses more rapidly in an unstable atmosphere than in
stable atmosphere. Although a plume appears less dense downwind in an
unstable atmosphere, if readings are taken at the source, atmospheric
stability has no significant; effect on the opacity.
Read at stack exit or source point.
-------
7.3
7.7 ATMOSPHERIC HAZE
The presence of haze, either natural or man-made, in the atmos-
phere will reduce the contrast between the plume and its background, and
hence will reduce the opacity reading. Atmospheric haze should not
significantly affect the opacity reading if the visibility is greater
than about three miles and the observation point is within % mile of the
emission point.
Readings should not be taken in poor visibility conditions.
7.8 SUN ANGLE
The particles in the plume scatter more light in the forward direc-
tion (at small angles with reference to the direction of the sun's rays).
A plume viewed such that the observer is looking toward the sun appears
to be more dense than a plume viewed with the sun located behind the
observer. A reading taken with the sun directly behind the observer will
produce the lowest opacity reading possible with the existing conditions,
but it has been found experimentally that the observed opacity is not
particularly sensitive to the sun's location provided the sun is behind
the observer, within an angle of about 70 with the line of sight,
The sun should be within a 140 sector oriented behind the
observer's back.
7.9 EFFECT OF OBSERVER DISTANCE ON OBSERVED OPACITY
As the observer moves closer to the base of the stack of an elevated
source the pathlength through the plume increases, so that the observed
opacity increases with decreasing observational distance, even though the
cross-plume opacity remains constant, (See Figure 7.1.) Table 7.1 below
compares the variation of the observed opacity with distance from the base
of the stack which is emitting a plume of 20% opacity. As shown in the
table the observed opacity, as evaluated from a distance of one stack
height (H) is 28%, whereas this value drops to 22% from a distance of 2H,
and 21% from a distance 3H.
-------
Plume
18
Y=3H —
Figure 7.1: EFFECT OF OBSERVER LOCATION ON OBSERVED PATHLENGTH
-------
7.5
Table 7.1: VARIATION OF OBSERVED OPACITY WITH
DISTANCE FROM AN ELEVATED SOURCE
OBSERVER
DISTANCE (Y)
H
2H
3H
OBSERVED
PATHLENGTH
1.41D
1.12D
1.05D
ACTUAL
OPACITY %
20
20
20
OBSERVED
OPACITY %
28.2
22.4
21.0
DEVIATION %
8
2
1
Significant increases in the observed opacity can therefore be intro-
duced if the observer selects an observation location that is very close to
the base of the stack. If observations are made from positions that are
very close to an elevated source the effect that this has on the opacity
readings should be carefully weighed if the readings are to be used as
testimony in subsequent legal proceedings.
As the observer moves further away from the source, the contrast
between the plume and the background decreases, causing a decrease in the
observed opacity. This is due to light scattering by the particles in the
air between the source and the observer, and it is particularly noticeable
when the visibility is not very good.
Earlier versions of Method 9 recommended that the observer should be
between two stack heights and a quarter or a mile from the source. While
these requirements are no longer valid, they do indicate approximately what
the distance between the source and the observer should be.
When evaluating an elevated sourcethe observershould be at a
suitable distance from the source.
7.10 TIME INTERVALBETWEEN READINGS
Staring continuously at the plume will result in eye fatigue resulting
in reduced visual acuity. For this reason the observer should glance at the
plume and make the opacity determination at regular intervals. The recom-
mended time interval between readings is 15 seconds. If longer time inter-
vals between readings are taken, the reasons for this should be shown on
the observation form.
Read at 15-second time intervals.
-------
7.6
7.11 SUMMARY OF RECOMMENDED OBSERVATIONAL PROCEDURES
Opacity readings should be taken:
• at 15-second intervals
• through the densest part of the plume
• under good lighting conditions
• with a contrasting background, if possible
• with the sun behind the observer
• with the plume being blown at right angles to the line of sight
• at a suitable distance from the source.
7.12 BIBLIOGRAPHY
1. Conner, W.D. and J.R. Hodkinson. Optical Properties and Visual Effects
of Smoke Stack Plumes. Department of Health, Education and
Welfare, PHS Publication No. 999-AP-30. 1967.
2. Hamil, H.F., R.E. Thomas and N.F. Swynnerton. Evaluation and Collabora-
tive Study of Method for Determination of Opacity of Emissions
from Stationary Sources. EPA, Research Triangle Park, N,C. 1975.
-------
8.1
8. APPLICABILITY OF VISIBLE EMISSIONS EVALUATIONS
8.1 ADVANTAGES
Opacity regulations (formerly Ringelmann and equivalent opacity
method) have been the foundation for the vast majority of particulate
control or enforcement actions in this country. The task of visible
emission compliance would be much more difficult without this simple but
effective means of source surveillance.
From the standpoint of the responsible air pollution control agency,
some of the advantages of the use of opacity regulations are:
(1) The validity of using the Ringelmann Chart and opacity
provisions has been well established in the field of air
pollution legislation by the courts,
(2) Observers can be qualified in about three days of training
and it is not necessary that the observers have an exten-
sive technical background. Recertification can be achieved
in one day, or less, every six months.
(3) No expensive equipment is required in comparison to alter-
native source measurement procedures.
(4) A qualified inspector can make several observations per day,
enabling a wide area to be inspected, particularly for those
agencies equipped with a helicopter or light aircraft,
allowing potential violators to be quickly located and iden-
tified.
(5) Violators can be cited without resorting to time-consuming
and costly source testing.
(6) Opacity regulations serve as an effective screening process
to reduce the number of expensive source tests required for
informational and enforcement requirements.
(7) Although it is usually not possible -to accurately quantify
the reduction in mass emissions by visual observations, there
is a definite relationship between reducing visible emissions
and improvements in particulate air quality.
-------
8,2
(8) Control can be achieved for those operations not readily
suitable to regular source testing methods, such as dust and
other leakage from process equipment, visible automobile
exhaust, and bulk loading, unloading, or storage of dusty
materials (grains, coal, ores, etc.)-
(9) Opacity regulations provide an expedient means for sources
to conduct self-appraisals and monitor their operating
conditions.
(10) The presence of visible emissions is prima facie evidence
that something other than clean air is present in the
atmosphere.
(11) It provides an excellent tool to bring minor or marginal
sources of pollution under control that would normally
be exempt under process weight restrictions.
(12) In most cases, a trained observer can distinguish smokes
and mists by color, behavior and dissipation point.
He can distinguish between emissions of smoke resulting
from rubbish burning, fuel-oil burning and even natural
gas, when gas-fired boilers are severely out of adjust-
ment, by color and escape velocity of the body of the plume.
(13) The results of such regulations provide an indication to
any observer (officials, citizens, etc.) that the agencies
maintain good operating practices and procedures.
(14) Opacity can be monitored and recorded automatically by means
of bolometers, photoelectric cells, etc., to ensure compliance
with the applicable regulations.
(15) Visible emissions are easily observed by laymen who can act as
"spotters" for the air pollution agency. Although laymen
cannot be considered as expert witnesses, they can serve to
inform the agency of possible violations of the regulations.
8.2 OBJECTIONS
The most common objections to the use of equivalent opacity, and
rebuttals to these objections, are given below:
-------
8.3
1.1 "The opacity observed is a subjective measurement, varying
with the position of the observer in relation to the sun and
sky, with the size of particles in the plume, stack diameter,
and with atmospheric lighting and background of the plume,"
1.2 This objection has been used for many years against the use of
the Ringelmann Chart for gray smoke, but to date no other
method has been found to be as practical and useful. It has
been shown that with adequate training, using consistent
observational procedures, an experienced observer can learn
to weight the opacity readings according to various conditions,
with good accuracy and reproducability.
2.1 "Opacity has not as yet been successfully correlated in detail
with other methods of measurement."
2.2 In recent years several plume opacity models have been deve-
loped that have shown good correlation between predicted and
observed opacity. The models do require that the input para-
meters, such as grain loading and particulate size distribution,
be well defined.
The particles causing the light scattering are in the submicronic
range and normally constitute a small percentage of the total
particulate emissions, whereas the particles causing light ab-
sorption are primarily greater than 10 microns in diameter.
Reducing the plume opacity therefore would result in a reduction
of the total particulate emissions, although not necessarily in
the same ratio.
3.1 "Gaseous emissions cannot be determined by equivalent opacity."
3.2 This is generally true since most, although not all, gaseous
emissions are invisible. However, the use of a visible emission
regulation should not be regarded as the only enforcement regu-
lation available to an air pollution agency and it does not
eliminate the need for qualified technical personnel, source
testing capability, a thorough understanding of the processes
leading to air pollutant emissions, and sound engineering and
administrative judgment.
-------
8.4
4,1 "Visible emission observations are difficult to make at night."
4.2 Provided the observer has been properly qualified to make
opacity determinations at night and the approved procedures
are followed, opacity observations can be made during the hours
of darkness. However, EPA does not have a procedure for night-
time evaluation at the present time.
5.1 "Water droplets interfere with the equivalent opacity obser-
vations."
5,2 Air pollution control regulations exempt visible emissions
which violate the opacity rule because of the presence of water
droplets In the plume, so that some allowance must be made for
those plumes whose opacity is derived from the presence of con-
densed water vapor. It is relatively simple to identify the
presence and exact location of a steam plume, and the problem
is easily handled by making the evaluation at a point in the
plume where condensed water is not present.
6.1 "The regulations concerning the opacity of emissions are ar-
bitrary and capricious,"
6.2 There are many legal precedents including a U.S. Supreme ruling
(Air Pollution Variance Board of the State of Colorado vs.
Western Alfalfa Corporation, - U.S. - 94 S. Ct. 2114. 1974)
which indicate that this is not the case. If a reading is made
in a proper manner by a trained observer, this is considered
to be a perfectly legal and valid measurement of the degree of
pollution created by visible emissions from a given source.
7.1 "It is difficult to secure guarantees from vendors that a con-
trol system can be designed to ensure that a source will
achieve compliance with the visible emission regulation."
7,2 For a given set of stack conditions it is possible to obtain
good correlation between opacity and grain loading. Vendors
can therefore design control equipment for a specific source
that will ensure compliance,
8.1 "Visible emission regulations can be circumvented by the intro-
duction of dilution air, or by reducing the exit diameter of the
stack."
-------
8.5
8.2 Normally the introduction of air in order to bring a source
into compliance is a contravention of the regulations. Reducing
the stack diameter may not be a contravention of the regulations,
however, this may not be a/very wise strategy for the source to
undertake, since compliance with the process weight and grain
loading regulations must still be achieved.
8.3 SUMMARY
While the arguments continue and positions remain polarized, the fact
remains that opacity regulations and their enforcement have unquestionably
proven to be an effective and dynamic abatement and compliance tool for use
in the control of air pollution.
The general public is probably more aware aware and concerned with
visible emissions than with any other aspect of the air pollution problem,
and the application of an opacity standard is a. very effective means of
demonstrating that measures are being taken to ameliorate the problem.
While enforcement actions based on opacity observations have been,
and probably will continue to be, challenged in the courts, if the obser-
vations are made according to the approved procedures by a properly quali-
fied inspector the courts will probably continue to accept opacity obser-
vations as a valid measure of the emissions from a source.
8.4 BIBLIOGRAPHY
1. Collis, R.R.H., Lidar Observation of Cloud, Science 149, 978-891. 1965.
2. Coons, J.D., et al, Development, Calibration and Use of a Plume
Evaluation Training Unit, J. Air Pollution Control
Assoc., 15, 199-203. 1965.
3. Crider, W.L. and J.A. Tash, Study of Vision Obscuration by Non-
Black Plumes, J. Air Pollution Control Assoc. 14, 161-
167, 1964.
4. Ensor, D.S. and Pilat, M.J., Calculation of Smoke Plume Opacity
from Particulate Air Pollution Properties, JAPCA, p.,496.
August, 1971.
5. Ensor, D.S. and Pilat, M.J.,Pluroe Opacity and Particulate Mass Con-
centration, Atmos. Env. 4, pp. 163-173. April 1970.
6. Ensor, D.S. and Pilat, M.J,, The Relationship Between the Visibility
and Aerosol Properties of Smoke Stack Plumes, Paper presented
at the Second International Union of Air Pollution Preven-
tion Associations in Washington, B.C. December 1970.
-------
8.6
7, Halow and Zeek, Predicting Ringelmann No. and Optical Characteristics
of Plumes, JAPCA, 676-684. August 1973.
8, Lucas, The Objective Calibration and Air Pollution Significance of
Ringelmann Numbers, Atmos. Env, Vol. 6, pp. 775-780. 1972,
9. Marks, L.S., Inadequacy of the Ringelmann Chart, Mech, Eng., p. 681.
1973.
10. Ringelmann, M., Method of Estimating Smoke Produced by Industrial
Installations, Rev. Technique, 268. 1898.
11. Rose, A.H., Nader, J.S., and Drinker, P,A, Development of an
Improved Smoke Inspection Guide, J. Air pollution Control
Assoc. 8, 112-116. 1958.
12. Rose, A.M. and Nader, J.S., Field Evaluation of an Improved Smoke
Inspection Guide, J. Air Pollution Control Assoc. 8,
117-119, 1958.
13. Stoecher, W.F., Smoke Density Measurement, Mech. Eng. 72, p. 793. 1950.
14. U.S. Department of the Interior, Ringelmann Smoke Chart , Information
Circular 8333. 1967.
15. Yocum, J.E., Problems in Judging Plume Opacity, J. Air Pollution
Control Assoc. 13, 36-39. 1963.
-------
9.1
9. PARTICLE SIZES AND THEIR CHARACTERISTICS
9.1 GENERAL
A particle is defined as any dispersed matei'ial, either solid or
liquid, in which the individual aggregates are larger than single small_
molecules (0.002 microns in diameter) but smaller than 500 microns.
Particles have a life-time in the suspended state varying from a few
seconds to several months. Chemically they are a most diverse class of
substances, although physically they do have a number of properties in
common. Table 9.1 gives a brief summary of the types of particles and
their characteristics.
The usual means of classifying particles is by their "size". Size
may be defined in several ways, although the most usual definition is to
classify particles by their "Stokes" or aerodynamic diameter, which is a
measure of their settling velocity. This settling velocity depends on
the configuration of the particle, so that a non-spherical particle is
classified by the Stokes diameter of a spherical particle that has the same
settling rate.
Although the distribution of particle sizes usually encountered in
the atmosphere closely approximates a log-normal distribution (Volzt1959),
shown in Figure 9.1 with a median size of 1 micron, the particle size
distribution in a plume is usually very different from this, and in addi-
tion the distribution is different for each type of source.
9.2 SIZES OF PARTICULATE MATTER EMISSIONS
Particles are produced by two mechanisms: those below 1 micron are
formed principally by condensation, while larger particles result from
comminution.
Combustion of fuels is a complex source of particulate emissions
with particles being formed in the following ways:
1. The heat may vaporize material which subsequently
condenses to yield particles in the size range
between 0.1 and 1 microns.
-------
Table 9.1? PARTICLE SIZES AND CHARACTERISTICS
Size (microns)
(mm)
Light
Light Scattering
Examples
Settling Velocity cm/sec.
0.1
0.0001
uv
Some
Carbon Black,
Fume,
Combustion
Nuclei
0.0002
0,5
0.0005
Visible
Yes
Tobacco
Smoke ,
Smog,
Oil Smoke
0.002
1
0.001
Near IR
Yes
Sulfuric
Acid Mist,
Talc, Clay
0.007
10
0.01
IR
Some
Cement
Dust,
Fog,
Bacteria
0.6
100
0.1
Far IR
Little
Human
Hair,
Mist, Sand
50
From: Sheehy et al, (1968)
-------
9.3
0.8
Count Mode (0.619
g
y
IS
0.6
0.4
0.2 -
0.0
Count Median (1.0 // )
Diameter of Average Mass (2.056/O
Area.Median (2.614//)
Area Mean (3.324
Mass Median (4.226^)
Mass Mean
(5.374/O
234
Particle Diameter (microns)
Figure 9.1: TYPICAL SIZE DISTRIBUTION OF PARTICLES IN THE ATMOSPHERE
SHOWING VARIOUS AVERAGE DIAMETERS (VOLZ , 1959)
-------
9.4
2. Particles of very small size are also produced
(below 0.1 microns); these particles may be of short
life as a result of their being simply unstable mole-
cular clusters.
3, Mechanical processes may reduce either fuel or ash to
particle sizes larger than 1 microns and may entrain it,
4. If the fuel is itself an aerosol during combustion, a
very fine ash may escape directly.
5. Partial combustion of fossil fuels may result in soot
formation.
Particles larger than 10 microns frequently result from mechanical
processes such as wind erosion, grinding, spraying, etc., although natural
precipitation is obviously not produced in this way.
NAPCA (1969) has given the size distributions of particulate
emissions from several major source categories:
Open-Hearth Furnaces (Silverman, 1955)
Majority of particles by number<0,1 microns
About 46% by weight<5 microns
Muni.cipa 1 Incinerators (Chass and Rose, 1953)
About 30% by weight<5 microns
Sulphuric Acid Manufacture
Chamber Process (NAPCA, 1969)
About 10% by weight <3 microns
Contact Process (U.S. Department of HEW, 1965)
About 63% by weight<3 microns
Cement Plants (Kreichelt, Kemnitz and Cuffe, 1967)
About 30% by weight <5 microns
About 20% by weight<2 microns
Automobiles (Mueller, Helwig, Alcocer, Gong, and Jones, 1964,
and Lee, Patterson, Crider and Wagman, 1968)
About 70% by weight <2 microns
About 90% of lead emissions is contained in particles<0.5 microns
-------
9.5
Fue1 Oil Comb us t i on
The size distribution of particulate emissions from large oil
burning units Table 9.2, was given by Smith (1962).
Table 9.2: SIZE DISTRIBUTION (% BYNUMBER)FROM OIL
COMBUSTION
Case
1
2
3
4
0-1M
48.4
64.2
93.5
94.8
i 9
1 ^
28.8
18.8
3.2
2.2
2^
16.7
10.0
2.0
1.5
>V
6.1
7.0 .
1.3
1.0
Largest
15
15
20
20
Coal Combustion
Size distributions for four coal-burning furnace types were given
by Smith and Gruber (1966) and are reproduced below in Table 9.3.
Table 9.3: WEIGHT PERCENT LESS THAK STATED SIZE FROM COAL. COMBUSTION
1
Particle Size
(M)
10
20
40
60
80
100
200
Pulverized Fuel
Fired Furnace
30
50
70
80
85
90
96
Cyclone
Furnace
76
83
90
92
94
95
97
Spreader
Stoker-Fired
Furnace
10
20
37
47
54
60
_
Stoker-Fired
(Other- than
Spreader)
7
15
26
36
43
50
66
9.3 EFFECT OF ATMOSPHERIC PARTICULATESONCLIMATE
Particles in the atmosphere play several roles in the behavior and
determination of the weather. One of ehe more obvious ways is the effect
they have on solar radiation, by scattering and absorbing the incoming
light to greater or lesser extents in different wavelengths depending upon
particle size, character and concentration, providing not only colorful
sunsets, but also dense, urban palls and reducing the amount of solar energy
-------
9.6
reaching the ground.
They play an essential role in the formation of clouds and in causing
precipitation from these clouds. The question has also been raised in
recent years of the long-term effects of high particulate loading in the
atmosphere. It has been suggested that a high atmospheric particulate
loading would lead to a reduction of the Earth's temperature, effected by
the particles absorbing the solar radiation before it is allowed to reach
the surface, although no conclusive evidence has been produced to date to
either prove or disprove this suggestion.
During the winter period there is increased usage of fossil fuels
for heating purposes, particularly in the colder areas of the country,
resulting in greater emissions of particulates to the atmosphere which
has the effect of reducing the amount of sunlight reaching the surface.
Sheleikovskii (1949) presented figures to show that in Leningrad this
reduction could be as high as 10% during the summer and 70% during the
winter.
9.4 ATTENUATION 07 SOLAR RADIATION
Solar radiation is attenuated during its passage through the atmos-
phere by four physical factors:
1. Scattering by the air molecules and particles which are smaller
than the wavelength of light. This is known as "Rayleigh
scattering." Scattering is inversely proportional to the fourth
power of the wavelength so that light of shorter wavelength
is scattered most, accounting for the blue color of the sky.
2. Selective absorption by the gases present in the atmosphere
(Ozone, Carbon Dioxide, water vapor, etc,)
3. Scattering by particulate matter which is roughly the same size
as the wavelength of light. This is known as "Mie scattering."
4. Absorption by particulate matter which is the same as, or
larger than, the wavelength of light.
Mie scattering is the dominant form of attenuation in the atmosphere,
and for plumes the other three factors may usually be ignored.
Visible light has a wavelength of between about 0.4 and 0.7 microns.
Particles within the 0.1 to 1 micron range scatter light more efficiently
than particles of other sizes. When light is scattered, more is scattered
in the forward direction (parallel to the direction of the light) than in
-------
9.7
other directions.
Scattering of light in the atmosphere reduces the contrast between
a target and its background i.e. visibility is reduced by the presence of
small particles in the atmosphere, Because of the forward scattering
mentioned above, visibility is greater when measured away from the sun
than when measured toward the sun.
9.5 HEALTH EFFECTS OF ATMOSPHERIC PARTICLES
Experiments by various workers, Dautrebande, Bechmann and Walken-
horst (1957) and Findeisen (1935), for example, have shown that particles
of small diameter settle out in the passageways of the human lung. It has
been shown that virtually all particles larger than 1 micron become trapped
in the respiratory system, and moreover, for particles of about 1 micron
in diameter, 80% are deposited in the alveolar region with a corresponding
value of 50% for 0.5 micron particles. It is in the alveoli that oxygen
from the air is transferred into the bloodstream, and waste gases are
transferred into the air, and if the subject is exposed to continually high
concentrations of these particles they will tend to decrease the lung
efficiency and eventually can lead to lung disease.
It should be noted here that the particles in the 0.5 to 1 micron
range, which do the most damage in the alveolar region, are also those
particles which are of the same size as the wavelength of light and have
the greatest effect on scattering the light, and therefore the greatest
effect on plume opacity. There is then a correlation between the plume
opacity, as determined by the observer in the field, and the amount of
lung-damaging particulate being emitted.
9.6 REMOVAL MECHANISMS
9.6.1 GRAVITATIONAL SETTLING
This is an important removal mechanism primarily for those particles
larger than about 20 microns, when settling occurs within a fairly short
distance from the source.
For a 50 micron particle the settling velocity is about 12 cm/sec,
so that if the release point is 100m above ground level the particle
-------
9.8
would reach the ground after about 14 minutes. With a wind speed of 5m/
sec. the particle would therefore reach ground level some 4 km from the
emission point.
For a 0.5 micron particle emitted from the same stack with the same
wind speed the settling velocity is only about 0.002 cm/sec, and ground
impact would not occur until some 250,000 km downwind, so that to all
intents and purposes these very small particles would remain in the atmos-
phere almost indefinitely, being transported across State and international
borders, unless there existed some other removal mechanism. Fortunately
there are other processes available for removal, such as coagulation,
rainout, washout and impaction.
The above times and distances should not be taken as absolute values
since the particles are affected by the turbulent eddies in the atmosphere,
with the result that some particles will settle out before the distances
given above, and some particles will settle out at considerably further
distances.
9.6.2 COAGULATION
When particles come into contact and adhere to one another the pro-
cess is called coagulation. Particles can come into close proximity be-
cause of their Brownian motion, resulting in thermal coagulation, or
superimposed on this there can also exist an orderly motion produced by
electrical, gravitational or other forces.
After coagulation has occurred the new particle has a larger gravita-
tional settling rate and different light scattering properties, compared to
the original.
9.6.3 RAINOUT
If there is sufficient water vapor present in the air, particles
that are 0.2 microns or larger in diameter act as nuclei for the formation
of raindrops.
-------
9.9
9.6.4 WASHOUT
Particles that are larger than about 1 micron can collide with and be
absorbed by raindrops. Particles smaller than about 1 micron have such
small inertia that the pressure forces surrounding a falling raindrop are
sufficiently large to prevent the particle from contacting the raindrop.
9.6.5 IMPACTION
When particles come into contact with a surface, such as a building
or vegetation, present in the atmosphere, they can settle out from the
flow and become loosely attached to the surface. This attachment can be
strengthened by any electrostatic attraction between the particle and
the surface.
9.7 BIBLIOGRAPHY
1. Bush, A. S. Municipal Incineration, Sanitary Engineering Research
Project, Technical Bulletin No. 6, University of
California, Los Angeles, California. 1951.
2. Cabe and Atkins, Wind Tunnel Study of Light Absorbance in a
Dispersing Smoke Plume. Texas Univ. Austin, Dept. of
Civil Eng. Env. Res. Lab., Tech. Dept., EHE-71-5,
P 30. 1971.
3. Chass, R. L. and A. H. Rose. Discharge from Municipal Incinerators.
Presented at 46th Annual Meeting, Air Pollution Control
Association. 1953.
4. Conner, W. D. and J. Raymond Hodkinson. Optical Properties and
Visual Effects of Smoke-Stack Plumes, DHEW, PHS
Publication No. 999-AP-30. 1967.
5. Crider, W. L. and J. A. Tash. Study of Vision Obscuration by Non-
Black Plumes, J, Air Poll. Control Assoc. 14 161-167. 1964.
6. Dautrebande, L., H. Bedmann and W. Walkenhorst. Lung Deposition of
Fine Dust Particles. Arch. Ind. Health, Vol. 16,
pp 179-187. 1957.
7. Ensor, D. S. and M. J. Pilat. Calculation of Smoke Plume Opacity
from Particulate Air Pollutant Properties, JAPCA,
p 496. 1971.
8. Ensor, D. S. and M. J. Pilat. Plume Opacity and Particulate Mass
Concentration, Atmos. Env., 4, p 163-173. 1970.
9. Ensor, D. S. and M. J. Pilat. The Relationship between the
Visibility and Aerosol Properties of Smoke Stack Plumes,
Paper presented at the Second International Union of Air
Pollution Prevention Associations in Washington, D.C. 1970.
-------
9.10
10. Findeisen, W. Uber das Absetzen Kleiner in der Luft suspendierten
Teilchen in der menshlichen Lunge bei der Atmung.
Arch. Ges. Physiol., Vol. 236, pp 367-379. 1935.
11. Gansler, N. R. The Use of a Bolometer for Continuous Measurement
of Particulate Losses from Kraft Mill Recovery Furnaces,
Pacific Northwest International Sections, APGA,
Vancouver, B.C. 1968.
12. Giese, R. H., E. de Bary, K. Bullrich and C. D. Vinnemann. Tables
of Scattering Functions, M = 1.50. Abhand, Deutch.
Skad. Wissenschaft. Berlin No. 6. 1961.
13. Halow and Zeek. Predicting Ringelmann No. and Optical Charact-
eristics of Plumes, APCA, 676-684. 1973.
14. Hawksley, P. G., S. Badzioch and J. Blackett. Measurement of
Solids in Flue Gases, British Coal Utilization Research
Assoc. Leatherhead, Surrey, England. 1961.
15. Hodkinson, J. R. Dust Measurement by Light Scattering and
Absorption, Ph. D. thesis, University of London. 1962.
16. Hodkinson, J. R. The Optical Measurement of Aerosols, in
Aerosol Science, ed. C. N. Davies, Academic Press,
London. 1966.
17. Hodkinson, J. R. The Refractive Index and Extinction Efficiency
Factor of Carbon, J. Opt, Soc. Araer., 54 846. 1964.
18. Hurley, T. F. and P. L. Bailey. The Correlation of Optical Density
with the Concentration and Composition of the Smoke
Emitted from a Lancashire Boiler. J. Inst. Fuel 31,
534. 1958.
19. Jarman, R. T. and C. M. de Turville. The Visibility and length
of Chimney Plumes, Atmo. Env. 3, 257. 1969.
20. Kreichelt, T. E., D. A. Kemnitz and S. T. Cuffe. Atmospheric Emissions
from the Manufacture of Portland Cement. U. S. Dept of
Health, Education and Welfare. Publication No. AP-17
1967.
21. Lee, R. E., Jr., R. K. Patterson, W. L. Crider and J. Wagman.
Concentration and Particulate Size Distribution of
Particulate Emissions in Auto Exhaust. 1968.
22. Lehr, P.E., R. W. Burnett and H. Z. Zim. Weather, a Guide to
Phenomena and Forecasts, Golden Press, New York. 1965.
23. McCormick, R. A. Air Pollution Climatology, Air Pollution Vol. 1,
edited by A. C. Stern. 1968.
24. McDonald, J. E. Visibility Reduction due to Jet-Exhaust Carbon
Particles, J. Appl. Met., 1, 391. 1962.
25. Middleton, W. E. K. Vision through the Atmosphere, University of
Toronto Press, pp. 83-102. 1963.
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9.11
26. Mueller, P. K., H. L. Helwig, A. E. Alcoccr, W. K. , Gong and E. E.
Jones. Concentration and Particle Size Distribution
of Particulate Emissions in Auto Exhaust. American
Society for Testing and Materials, Spec. Tech. Pub.
352, 1968.
27. NAPCA. Air Quality Criteria for Particulate Matter. U. S. Dept.
of Health, Education and Welfare. Publication No.
AP-49. 1969.
28. Penndorf, R. B. New Table of Mie Scattering Functions, Part 6,
Geophysical Research Paper No. 45, AFCRC-TR-56-204/6,
Air Force Cambridge Research Laboratory, Bedford, Mass.
1956.
29. Penndorf, R. B. Research on Aerosol Scattering in the Infra-Red,
Final Report, AFCRL-63-668, Air Force Cambridge Research
Laboratory, Bedford, Mass. 1963.
30. Robinson, E, Effect on the Physical Properties of the Atmosphere,
Air Pollution Vol. 1, edited by A. C. Stern.
31. Sheehy, J. P., W. C. Achinger and R. A. Simon. Handbook of Air
Pollution. U. S. Dept. of Health, Education and Welfare,
Publication No. AP-44. 1968.
32. Sheleikhovskii, G. V. Smoke Pollution of Towns. Translated from
Russian and published by the National Science Foundation.
1961.
33. Silverman, L. Technical Aspects of High Temperature Gas Cleaning
for Steel Making Processes. Air Repair, Vol. 4, pp.
189-196. 1955.
34. Smith, W. S. and C. W. Gruber. Atmospheric Emissions from Coal
Combustion. An Inventory Guide. U. S. Dept. of Health,
Education and Welfare, Publication No. AP-24. 1966.
35. Smith, W. S. Atmospheric Emissions from Fuel Oil Combustion.
U. S. Dept. of Health, Education and Welfare,
Publication No. AP-2. 1962.
36. Stoecher, W. F. Smoke Density Measurement, Mech. Eng. 72, 793. 1950.
37. U. S. Dept. of Health, Education and Welfare. Atmospheric Emissions
from Sulfuric Acid Manufacturing Processes.
Publication No. AP-2. 1965.
38. Van De Hulst, H. C. Light Scattering by Small Particles, John Wiley
& Sons, Inc., New York. 1957.
39. Volz, F. A Photometer for Measurement of Solar Radiation, Arch.
Met. Geophys. & Bioklimat. B 10, 100-131. 1959.
40. Wanta, R. C. Meteorology and Air Pollution, Air Pollution Vol. 1,
edited by A. C. Stern. 1968.
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10.1
10. AIDS FOR EVALUATING VISIBLE EMISSIONS
10.1 INTRODUCTION
A number of aids for evaluating the opacity of visible emissions
has been developed, ranging from a simple hand-held Ringelmann chart to
sophisticated laser techniques. The aids vary in price from a few cents
to tens of thousands of dollars. Although some are useful for research
purposes, none of them produces any significant improvement over an
inspector who has been properly trained to evaluate emissions.
10.2 SMOKE CHARTS
The various smoke charts that have been developed work on the
Ringelmann principle by comparing shades of gray printed on paper, with
the source emission. They are simply smaller, hand held Ringelmann charts,
and should be used to evaluate gray or black emissions.
10.3 SMOKEINSPECTION GUIDE
The Public Health Service has developed a film strip comprised of
pieces of film with densities of zero, 20, 40, 60 and 80 percent trans-
mission, and which is referred to as a "Smoke Inspection Guide." The
inspector views the source through the guide and evaluates the opacity
of the source by comparing it to the pieces of film on the guide. Of
all the aids available this guide is probably the best from a "cost-
effectiveness" standpoint for observations in connection with enforcement
proceedings.
10.4 COMPARATORS
These include the smoke tintometer and the umbrascppe which use
tinted glasses graduated to the Ringelmann scale against which the opacity
of the emissions may be compared.
10.5 SMOKESCOPE
This instrument consists of two barrels for receiving incoming light,
similar to binoculars, with one eyepiece for viewing. The stack is viewed
through one barrel of the instrument. Light from an area adjacent to the
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10.2
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 discs
is projected onto a screen in front of the eyepiece and this image surrounds
a small aperture 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 illumina-
tions of the smoke and the reference are both influenced by the same factors,
Thus, the smokescope is automatically compensated for varying light condi-
tions. (The amount of light transmitted is used to evaluate plume opacity,
while the amount of light reflected is used to evaluate a conventional
Ringelmann chart).
10.6 PHOTOGRAPHY
Photographs of the source can be used to evaluate the plume trans-
mittance by placing filters along the side of the camera film plane so that
a calibration scale is superimposed on the photograph.
10.7 TELEPHOTOMETERS
Telephotometers are used to measure the luminance of a source, often
using a bright light source as a datum.
10.8 TRANSMISSOMETERS
Many permanently installed, in-stack devices are commercially avail-
able to continuously monitor and record the emission transmittance. Some
are designed to set off an alarm to warn operating personnel when the
transmittance reaches a preset level. Others indicate the transmittance
on a meter, or record it on a strip chart.
Most of these devices use either a light source-photocell combina-
tion to measure the transmission of light through the plume, or remove a
sample of the plume and measure the transmission of light through this
sample. One problem with the light source photocell system is that both
the light source and photocell deteriorate with time and require frequent
recalibration. If the light transmission of a sample is measured, it is
frequently difficult, especially under varying conditions, to obtain a
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10.3
representative sample.
The bolometer is another device available that uses the same general
principal as the light source photocell. This device measures the resis-
tance change across a filament which is proportional to the light that is
transmitted through the emission. According to the manufacturer the main
advantage of the bolometer over the light source-photocell system is that
bolometers do not need to be calibrated as often.
10.9 LASER TECHNIQUES
Laser techniques for measuring the transmittance of plumes have
recently been developed. The method is based on the measurement of back-
scatter signals of a pulsed laser beam by aerosols in the air beyond a
plume. The plume's transmittance is obtained by comparing the backscatter
signal when the beam is directed through the plume to the backscatter
signal obtained when the beam is directed beside the plume.
10.10 BIBLIOGRAPHY
1. Collis, Ronald T.H., Lidar Observation of Cloud, Science 149, 978-981.
1965-
2. Gansler, N.R., The Use of a Bolometer for Continuous Measurement of
Particulate Losses from Kraft Mill Recovery Furnaces,
Pacific Northwest International Sections, APCA,
Vancouver, B.C. 1968.
3. Hawksley, P.G., S. Badzioch and J. Blackett, Measurement of Solids in
Flue Gases, British Coal Utilization Research Assoc.
Leatherhead, Surrey, England. 1961.
4. Hodkinson, J.R., The Theory of the Tyndahlscope, Staub. March 1966.
5. McKee, Instrumental Method Substitutes for Visual Estimation of Equi-
valent Opacity, APCA, 488. August 1971.
6. Rose, A.H., J.S. Nader and P.A. Drinker, Development of an Improved
Smoke Inspection Guide, J. Air Poll. Control Assoc. 8,
112-116. August 1958.
7. Rose, A.H. and J.S. Nader, Field Evaluation of an Improved Smoke
Inspection Guide, J. Air Poll. Control Assoc. 8, 117-119.
August 1958.
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11.1
11. DEFINITIONS
11.1 POLLUTANT CLOUD
A cloud of air pollution is an emission of air contaminants which
has become completely divorced from its source or sources and is gradually
being dissipated by the processes of dilution, gravitational settling and
diffusion, but may still retain visible boundaries. The cloud is shaped
by the direction of air flow, and by dilution which occurs at right
angles to this flow. The cloud is the extension or the fanning effect,
of the plume and generally occurs under stable atmospheric conditions.
Clouds are often produced from large source emissions and from building,
brush and forest fires. Generally speaking, the larger the quantity of air
pollutants, the longer a cloud remains coherent.
Noting the appearance of clouds in reports, especially as to height,
length, breadth and thickness, can be important in determining the severity
of a general or local problem.
11.2 HAZE
Hazes are frequently formed by condensation of vapors on atmospheric
particles, or by aerosol production in smog formation, and by dusts and
pollen. Smog is itself a chemical haze. A haze may also be considered
as a more attenuated form of cloud residing at ground level, representing
Stagnant atmospheric conditions. Notation of the existence of the haze
is important, particularly when it is peculiar to a community, since an
acute local problem may be present.
11.3 TYPES OF EFFLUENT
The plume represents the form of the air contaminant of primary
interest. It is the "discharge" or "emission" regulated or prohibited in
most statutes or rules.
Since all substances become liquid, solids and gases at certain
temperatures, the plume may consist of a variety of contaminants in
various states of matter. Smoke, for instance, contains visible aerosols—
carbon particles and solid or liquid particles of partially burned fuels—
and such gases as sulfur dioxide, oxides of nitrogen, and unburned vapors.
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11.2
The identity ascribed to the plume is usually made in terms of
its outstanding visual characteristic. For example, even though sulfur
dioxide may be the most significant of the pollutants emitted from a
given stack, the effluent in which it is contained is frequently des-
cribed as smoke due to the visible soot, carbon particles and fly ash
contained in the plume.
The mere observation of a plume, however, does not result in its
conclusive identification. Knowledge of the specific conditions which
caused the contaminants is required. The distinction between smoke and
fumes cannot be made unless the processes by which they are generated are
described.
11.3.1 SMOKE
Smoke is the visible effluent resulting from incomplete combustion.
It consists mostly of soot, fly ash and other solid or liquid particles
less than one micro-meter in diameter. Depending upon the composition
of the fuel or materials being burned and the efficiency of combustion,
various volatilized gases and organics such as aldehydes, various acids,
sulfur oxides, nitrogen oxides and ammonia may also be emitted. Due to
the low vapor pressures and slow settling properties of the particles,
the smoke may be carried considerable distances from the source and many
submicro-meter particles will remain dispersed in the atmosphere almost
permanently.
Smoke will vary in color, but will be generally observed as grey,
blue, black, brown and white, and sometimes yellow, depending upon the
conditions under which certain types of fuels or materials are burned.
The color of smoke is generally a fairly good indication of the type of
combustion problem encountered.
Smoke which is grey or black in color may indicate that material
is being burned with insufficient air or inadequate mixing of fuel and
air.
White smoke usually results when combustion is cooled by excessive
drafts of air, or when the materials being burned contain excessive
amounts of moisture. In the latter case, of course, a condensed water
vapor plume is not subject to the opacity regulation.
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11.3
Brown or yellow smoke may result from the burning of semi-solid
tarry substances such as asphalt or tar paper, resulting from inadequate
temperature or poor mixing.
A blue color or light blue color is often associated with the burning
of domestic trash consisting mostly of paper or wood products. The
light blue color seems to stem from the fine particles of pyroligneous
acid due to sulfide treated paper and wood tar constituents. The blue
plume contains little or no carbon or soot particles.
11.3.2 FUMES
In air pollution control, fumes are referred to specifically as
"condensed fumes." These are minute solid particles generated by the
condensation of vapors from solid matter after volatilization from the
molten state, or may be generated by sublimation, distillation, calcination
or chemical reaction when these processes create air-borne particles.
Fume particles are generally less than one micro-meter in diameter and
will behave like smoke. Fumes will more commonly consist of metals and
metallic oxides and chlorides. Also contained in the fumes are common solid
particulates such as fly ash, carbon, mechanically-produced dust and gases
such as sulfur dioxide. The fumes principally emitted, however, are actually
dusts condensed from the more volatile elements in the metals melted such
as zinc, sulfur, lead and others.
Metallurgical operations are the most common form of fume which
consists primarily of the metallic oxide driven from the melting
surface when metal is heated to the molten state. Metals such as copper
and bronze with relatively high boiling temperatures, as compared to their
melting and pouring temperatures, do not readily volatilize and do not
constitute an air pollution problem. Copper and tin, for example, have
boiling temperatures above 4000 F., but are poured at temperatures at
about 2000°F.
Some metals may contain alloys with extreme differences in volatility.
Copper-based alloys such as yellow brass, manganese bronze, brazing spelter
and various plumbing tnetals contain from 14 to 40 percent zinc, the boiling
temperature of which is around 2200 F. Since the metal must be heated to
melt the copper which has the highest pouring temperature, a portion of the
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11. A
zinc will be brought to its boiling point and will volatilize. Copper
alloys with high zinc contents may lose from 2 to 15 percent of their
zinc through fuming.
When vented to the atmosphere, fumes may have the appearance of
snoke. However, all of the sources of fumes may not be practically
vented in a large-scale foundry operation, so that fumes in the vicinity
of a plant may appear as a haze or a cloud emitted from factory monitors
and windows.
Other processes which will produce fumes include calcination., sub-
limation and distillation.
Calcination consists of heating, roasting or smelting to decompose
minerals. Calcination is commercially applied in the manufacture of glass
and mineral catalysts through the heating of materials such as sand and
limestone. It is variously employed to remove moisture or a volatile con-
stituent by such methods as heating limestone to form carbon dioxide gas
and calcium oxide, or to reduce minerals by oxidation.
Sublimation is the process in which a solid substance is converted
to a gas without a change in composition and without first going through
the liquid state. Iodine, carbon dioxide (dry ice) and many metallic and
nonmetallic crystals are examples of sublimed materials. Sublimation of these
materials may be accomplished by lowering the pressure, raising the tem-
perature or by changing both temperature and pressure.
Distillation is a cycle of vaporization and condensation in which
a liquid is converted to a vapor and condensed to 3 liquid. Distillation
is generally employed to purify a liquid or to segregate components
according to relative volatility.
11.3.3 DUSTS
Dusts are minute solid particles released in the air by natural
forces or by mechanical processes such as crushing, grinding, melting,
drilling, demolishing, shoveling, sweeping, sanding, etc. Dust particles
are larger and less concentrated than those in colloidal systems, such
as smoke and fumes, and will settle fairly quickly on surfaces. A dust
effluent, however, may also contain many submicroscopic particles.
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11.5
Dusts are produced from virtually every human activity as well as
from the natural environment. Some dusty industries include mineral
earth processors such as ceramic and cement manufacturing, calcining,
and wood-working and feed, and flour industries.
Dust particles mainly exceed one macron in diameter and are readily
controlled by centrifugal separators, cloth filters and electrostatic
precipitators.
11.3.4 MISTS
Mists consist of liquid particulates or droplets, less than the size
of raindrops, such as fog, and are formed by condensation of a vapor, or
atomization of a liquid by mechanical spraying. Mist droplets may contain
contaminant material in solution or suspension. The impregnation and
coating of building materials with asphalt or the manufacture or heating
of asphalt at batch plants may produce hazes or fogs containing droplets
of liquid asphalt. Paint spraying operations emit liquid particulates
containing organic solvents, pigments and other materials. Mists may also
be emitted from control devices such as•cyclones and scrubbers, using a
liquid air cleaning medium. Acid particulates, such as chromic and sulfuric
acid produced from chrome plating operations, may also form mists when
exhausted to the atmosphere.
In large oil-burning installations., sulfur trioxide is formed as
a gas, and, after contact with sufficient moisture in the air, forms as
a white-to-blue plume several feet above the stack (detached plume).
After further contact with moisture in the air, the sulfur trioxide is
transformed to a sulfuric acid mist.
11.3.5 GASESAND VAPORS
Most gaseous and vapor plumes are colorless. If they are visible
however, e.g. a,chlorine or nitrogen dioxide emission, it would probably
be wiser for the inspector to report these emissions to a plant official
at once rather than to attempt to prove a violation of the opacity
regulation. Emissions of some gases in quantities of sufficient magnitude
to violate the opacity regulation would very likely constitute a real
threat to human health and the local environment, and every attempt should
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11.6
be made to stop the emissions as soon as possible.
11.A BIBLOGRAPHY
1. Weisburd, M.I. (Editor), Identifying Effluent Plumes, Air Pollution
Control Field Operations Manual, PHS Publication No. 937. 1962.
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12.1
12• METHOD 9 — VISUAL DETERMINATION OF THE OPACITY OF EMISSIONS FROM
STATIONARY SPURGED ~"~ ~~~"
The current Method 9, published in the Federal Register, Volume
39, No. 219 on November 12, 1974 is reproduced below.
Many stationary sources discharge visible emissions into the atmos-
phere; these emissions 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 obser-
vers, 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 number of variables, some of which may be controllable and some 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 observer with re-
spect 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 respect 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 controllable in the field are
luminescence and color contrast between the plume and the background
against which the plume is viewed. These variables exert an influence
upon the appearance of a plume as viewed by an observer, and can affect
the ability of the observer to accurately assign opacity values to the
observed plume. Studies of the theory of plume opacity and field studies
have demonstrated 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 background is
present can be assigned with the greatest degree of accuracy. However, the
potential for a positive error is also the greatest when a plume is viewed
under such contrasting 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
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12.2
bias decreases rather than increases the possibility that a plant opera-
tor will be cited for a violation 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 reading 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:
1) For black plumes (133 sets at a smoke generator),100
percent of the sets were read with a positive error
of less than 7.5 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 sul-
furic acid plant), 99 percent of the sets were read
with a positive error of less than 5 percent 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.
1. PRINCIPLE AND APPLICABILITY
1.1 PRINCIPLE
The opacity of emissions from stationary sources is determined
visually by a qualified observer.
1.2 APPLICABILITY
This method is applicable for the determination of the opacity of
emissions from stationary sources pursuant to § 60.11 (b) and for quali-
fying observers 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 visually determining the opacity of
emissions.
For a set, positive error = average opacity determined by observers' 25
observations - average opacity determined from transmissometer's 25 recordings.
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12,3
2.1 POSITION
The qualified observer shall stand at a distance sufficient to pro-
vide a clear view of the emissions with the sun oriented in the 140°
sector to his back. Consistent with maintaining the above requirement,
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 rect-
angular outlets (e.g. roof monitors, open baghouses, noncircular stacks),
approximately perpendicular to the longer axis of the outlet. The obser-
ver'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
observations with his line of sight perpendicular to the longer axis of
such a set of multiple stacks (e.g. stub stacks on baghouses).
2.2 FIELD RECORDS
The observer shall record the name of the plant, emission location,
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 readings are initiated
and completed.
2.3 OBSERVATIONS
Opacity observations shall be made at the point of greatest opacity
in that portion of the plume where condensed water vapor is not present.
The observer shall not look continuously at the plume, but instead shall
observe the plume momentarily at 15~second intervals.
2.3.1 ATTACHED STEAM PLUMES
When condensed water vapor is present within the plume as it
emerges from the emission outlet, opacity observations shall be made be-
yond the point in the plume at which condensed water vapor is no longer
visible. The observer shall record the approximate distance from the
emission outlet to the point in the plume at which the observations are made.
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12.4
2.3.2 DETACHED STEAM PLUME
When water vapor in the plume condenses and becomes visible at a
distinct distance from the emission outlet, the opacity of emissions should
be evaluated at the emission outlet prior to the condensation of water
vapor and the formation of the steam plume.
2.4 RECORDING OBSERVATIONS
Opacity observations shall be recorded to the nearest 5 percent at
15-second intervals on an observational record sheet. (See Figure 9-2 for
an example). A minimum of 24 observations shall be recorded. Each
momentary observation recorded shall be deemed to represent the average
opacity of emissions for a 15-second period.
2.5 DATA REDUCTION
Opacity shall be determined as an average of 24 consecutive observations
recorded at 15-second intervals. Divide the observations recorded on the
record sheet into sets of 24 consecutive observations. A set is composed
of any 24 consecutive observations. Sets need not be consecutive 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 observations, calculate the average for all
observations 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 candidate 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.
Candidates shall be tested according to the procedures described in para-
graph 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.
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12.5
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 certification 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 random order. The candidate assigns an opacity
value to each plume and records his observation on a suitable form. At the
completion of each run of 50 readings, the score of the candidate is de-
termined. If a candidate fails 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 preceded 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 generator used for the purpose of paragraph 3.2 shall be
equipped with a smoke meter installed to measure opacity across the dia-
meter of the smoke generator stack. The smoke meter output shall display
in-stack opacity based upon a pathlength equal to the stack exit diameter,
on a full 0 to 100 percent chart recorder scale. The smoke meter optical
design and performance shall meet the specifications shown in Table 9-1.
The smoke meter shall be calibrated as prescribed in paragraph 3.3.1 prior
to the conduct of each smoke reading test. At the completion of each test,
the zero and span drift shall be checked and if the drift exceeds + 1 per-
cent opacity, the condition shall be corrected prior to conducting any sub-
sequent 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 following any subsequent repair or replace-
ment of the photocell or associated electronic circuitry including the
chart recorder or output meter, or every 6 months, whichever occurs first.
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12.6
TABLE 9-1: SMOKE METER DESIGN AND
PERFORMANCE SPECIFICATIONS
Parameter Specification
a. Light source Incandescent lamp operated at nominal
rated voltage.
b. Spectral response of photocell Photopic (daylight spectral response
of the human eye - reference 4.3).
c. Angle of view 15 maximum total angle.
d. Angle of projection 15 maximum total angle.
e. Calibration error- + 3% opacity, maximum
f. Zero and span drift + 1% opacity, 30 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 adjusted to produce an output of 0 percent or 100 percent as
appropriate. This calibration shall be repeated until stable 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.
3.3.2 SMOKE METER EVALUATION
The smoke meter design and performance are to be evaluated as
follows:
3.3.2.1 LIGHT SOURCE
Verify from manufacturer's data and from voltage measurements made
at the lamp, as installed, that the lamp is operated within + 5 percent of
the nominal rated voltage.
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12.7
3.3.2.2 SPECTRAL RESPONSE OF PHOTOCELL
Verify from manufacturer's data that the photocell has a photopic '
response; i.e., the spectral sensitivity of the cell shall closely
approximate the standard spectral-luminosity curve for photopic vision
which is referenced in (b) of Table 9-1.
3.3.2.3 ANGLE OF VIEW
Check construction geometry to ensure that the total angle of view
of the smoke plume, as seen by the photocell, does not exceed 15 . The
total angle of view may be calculated from: (9=2 tan d/2L, where 8= total
angle of view; d=the sum of the photocell diameter + the diameter of the
limiting aperture; and L=the distance from the photocell to the limiting
aperture. The limiting aperture is the point in the path between the
photocell and the smoke plume where the angle of view is most restricted.
In smoke generator smoke meters this is normally an orifice plate.
3.3.2.4 ANGLE OF PROJECTION
Check construction geometry to ensure that the total angle of pro-
jection of the lamp on the smoke plume does not exceed 15 . The total
angle of projection may be calculated from: d~2 tan d/2L, where &= total
angle of projection; d=the sum of the length of the lamp filament + the
diameter of the limiting aperture; and L=the distance from the lamp to the
limiting aperture.
3.3.2,5 CALIBRATION ERROR
Using neutral-density filters of known opacity, check the error
between the actual response and the theoretical linear response of the
smoke meter, This check is accomplished by first calibrating the smoke
meter according to 3.3.1 and then inserting a series of three neutral-
density filters of nominal opacity of 20, 50, and 75 percent in the smoke
meter pathlength. Filters calibrated within + 2 percent shall be used.
Care should be taken when inserting the filters to prevent stray light
from affecting the meter. Make a. total of five nonconsecutive rea.dings
for each filter. The maximum error on any one reading shall be 3 percent
opacity.
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12.8
3.3.2.6 ZERO AND SPAN DRIFT
Determine the zero and span drift by calibrating and operating the
smoke generator in a normal manner over a 1-hour period. The drift is
measured by checking the zero and span at the end of this period.
3.3.2.7 RESPONSE TIME
Determine the response time by producing the series of five simulated
0 percent and 100 percent opacity values and observing the time required to
reach stable response. Opacity values of 0 percent and 100 percent may be
simulated by alternately switching the power to the light source off and on
while the smoke generator is not operating.
4. REFERENCES
4.1 Air Pollution Control District Rules and Regulations, Los Angeles
County Air Pollution Control District, Regulation IV, Prohibitions, Rule
50.
4.2 Weisburd, Melvin I., Field Operations and Enforcement Manual for Air,
U.S. Environmental Protection Agency, Research Triangle Park, N.C., APTD-
1100, August 1972. pp. 4.1-4.36.
4.3 Condon, E.U., and Odishaw, H., Handbook of Physics, McGraw-Hill Co.,
N.Y., N.Y. 1958, Table 3.1, p. 6-52."
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13.1
TECHNICAL REPORT DATA
{Please read Injunctions on the reverse before completing}
, REPORT NO,
3, RECIPIENT'S ACCESSfQP*NO.
EPA-340/1-75-007
4. TITLE AND SUBTITLE
Guidelines for Evaluation of Visible Emissions
Certification, Field Procedures, Legal Aspects,
and Background Material
5. REPORT DATE
April 1975
, AUTMOR(S)
Robert Missen and Arnold Stein
6, PERFORMING ORGANIZATION CODE
8, PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Pacific Environmental Services Inc.
1930 14th Street
Santa Monica, California 90404
12, SPONSORING AGENCY NAME AND ADDRESS
D. S. Environmental Protection Agency
Division of Stationary Source Enforcement
401 M Street SW
Washington, DC 20460
1O, PROGRAM ELEMENT NO,
TiTCONTRACTAfHANT KfoT
68-02-1390, Task 2
13, TYPE OF REPORT AND PERIOD COVERED
14, SPONSORING AGFNCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This report provides guidelines for:
(a) Field procedures to follow in evaluating visible emissions from stationary
sources of air pollution, (Procedures are included for evaluation of non-
stack emission sources such as are found in the minerals industry as well
as specific stack emission sources.)
(b) Visible emissions evaluator regarding specific problems of applicability,
including the effects of viewing conditions on opacity readings and the
effects of water vapor on plume opacity.
Also included are training and certification procedures for visible emissions
evaluation, brief descriptions of affected process operations, general instruction
on being a witness during legal proceedings involving opacity evaluations, and the
use of aids in evaluating visible emissions
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Air Pollution
Visible Emissions Evaluations
Plume
Observations
Litigation
Water Vapor
b-IDENTIFtEHS/OPEN ENDED TERMS
Visible Emissions
COSATI Field/Croup
14B
14D
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS (This fit-port}"
Unclassified
21. NO. OF PAGES
132
Unlimited
j 20. SECURITY CLASS (This page)
22. PRICE
Unclassified
EPA Form 2220-1 (9-73)
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ENVIRONMENTAL PROTECTION AGENCY
Technical Publications Branch
Office of Administration
Research Triangle Park, North Carolina 27711
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EPA - 335
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AN EQUAL OPPORTUNITY EMPLOYER
Return this sheet if you do NOT wish to receive this material i" ,
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PUBLICATION NO. EPA-340/1-75-007
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