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Document Number: 

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Printed 4/18/2008 10:52:08 AM Sheet 73 of 94 
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EPA-340/1-75-007 

April 1975 Stationary Source Enforcement! Series 

HI 

[Hi 

GUIDELINES FOR EVALUATION 

OF VISIBLE EMISSIONS ' 

" -

 ,:

 * ' * 

CERTIFICATION, 

FIELD PROCEDURES, LEGAL ASPECTS, 

AND BACKGROUND MATERIAL 

n# |p—3 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

Office of Enforcement 

Office of General Enforcement 

Washington, D.C. 20460 
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:ri r'"it •--

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 Orde r No. 2 

Project Officer: Kenneth B . Malmberg 

Division of Stationary Sourc e Enforcement 

Prepare d for: 

U.S . ENVIRONMENTAL PROTECTION AGENCY 

Office of Enforcement 

Office of General Enforcement 

Washington, D.C . 20460 

April 1975 
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i i 

The Enforcement Technica l Guideline serie s of reports is issued by the 

Office of Enforcement, Environmental Protection Agency, to assist the 

Regional Offices in activities related to enforcement of implementation 

plans, new sourc e emission standards, and hazardous emission standard s 

to be developed unde r the Clean Air Act. Copies of Enforcement Technica l 

Guideline reports are available - as supplies permit - from Air Pollution 

Technical Information Center, Environmental Protection Agency, Research 

Triangl e Park , North Carolina 27711, or may be obtained, for a nominal 

cost, from the National Technical Information Service , 5285 Port Royal 

Road, Springfield, Virginia 22161. 

This report wa s furnished to the Environmental Protection Agency by the 

Pacific Environmental Services, Inc . , Santa Monica, California 90404, in 

fulfillment of Contract No. 68-02-1390, Task Orde r No. 2. This report has 

been reviewed by the Environmental Protection Agency and approved for 

publication. Approval does not signify that the contents necessarily 

reflect the views and policies of the Agency, nor does mention of trade 

names or commercial products constitute endorsement or recommendation 

for use . 

Publication No. EPA-340/1-75-007 
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111 

ACKNOWLEDGEMENTS 

Much of the information contained in this manual was supplied by 

i 

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 tp 

thank Karl Luedtke who acted as a consultant on this contract. 
P.6 

,-,.., • 

TABLE OF CONTENTS 

P;age 

I 

LIST. OF FIGURES ' i x 

LIST OF TABLES

 i x 

CHAPTER 1. INTRODUCTION „1.1 

1.1 Genera l il.l 

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 i2. 6 

2.6 Apprenticeship Period . J2.7 

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 

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 . J 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 
Pafie 

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3.5.7 Sketch 

3.5.8 Photographs 

3.5.9 Number of Observers 

3.5.10 Data Reduction 

3.5.10.1 "Average Opacity" Concept . . . 

3.7.10.2 "Time" Concempt ....... . 

3.6 Source Inspection 

3.7 Bibliography 

CHAPTER 4. SOURCES OF VISIBLE EMISSIONS 

4.1 Introduction 

4.2 Procedures for Non-stack Emission Sources ... . 

4.2.1 Roof Monitors 

4.2.2 Material Handling Operations 

4.2.2.1 Drilling 

4.2.2.2 Crushing 

4.2.2.3 Conveying 

4.2.2.4 Screening 

4.2.2.5 Stockpiling 

4.2.3 Coking Operations 

4.2.3.1 Charging Operations 

4.2.3.2 Pushing Operations 

4.2.3.3 Door Leakage 

4.2.3.4 Storage 

4.3 Procedures for Specific Stack Emission Sources 

4.3.1 Power Plants, Refinery Heaters, Boilers 

and Miscellaneous Fuel Burning Equipment 

4.3.2 Refineries . 

4.3.3 Resin Kettles and Varnish Cooking 

Kettles 

4.3.4 Sulfuric Acid Manufacturing 

4.3.5 Phosphoric Acid Manufacturing 

4.3.6 Soap and Detergent Manufacturing 

4.3.7 Glass Manufacturing 

4.3.8 Frit Smelters 

4.3.9 Food Processing 

4.3.9.1 Meat Smoking 

4.3.9.2 Fish Meal Driers 

4.3.10 Paint Baking ... . 

4.3.11 Incinerators 

4.3.12 Hot-Mix Asphalt Paving Batch Plants . . . 

4.3.13 Concrete Batching Plants. 

4.3.14 Stone Quarrving,Rock and Gravel Plants . . 

4.3.15 Mineral Wool Furnaces 

4.3.16 Perlite-Expandmg Furnaces 

4.3.17 Feed and Grain Mills 

4.3.18 Pne-..i.atic Conveying and Drying 

3.13 

3.13 

3.15 

3.15 

3.15 

3.15 

3.15 

3.16 

4.1 

4.1 

4.1 

4.1 

4.3 

4.3 

4.3 

4.3 

4.6 

4.6 

4.6 

4.6 

4.8 

4.8 

4.8 

4.8 

4.8 

4.11 

4.13 

4.14 

4.14 

4.15 

4.16 

4.17 

4.17 

4.18 

4.18 

4.18 

4.19 

4.20 

4.20 

4.2] 

4.22 

4.22 

4.23 

4.23 
Vii 

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'Page 

4.3.19 Woodworking Equipment 4.24 

4.3.20 Asphalt Roofing Felt Saturators 4.24 

4.3.21 Abrasive Blast Cleaning 4.25 

4.3.22 Zinc-Galvanizing Equipment t 4.25 

4.3.23 Ceramic Spraying and Metal Deposition i 

Equipment 4.26 

4.3.24 Steel Manufacturing Processes 4.26 

4.3.25 Iron Casting 4.28 

4.3.26 Secondary Brass-and Bronze-Melting 

Processes i 4.28 

4.3.27 Secondary Aluminum Melting and Smelting . . 4.29 

4.3.28 Secondary Zinc-Melting Processes 4.29 

4.3.29 Lead Refining

 l 4.30 

4.3.30 Metal Separation Processes 1 4.31 

4.3.31 Foundry Sand-Handling Equipment j 4.31 

4.3.32 Kraft Pulp Mills 4.31 

4.3.33 Cement Plants 4.32 

4.3.34 Aluminum Reduction Plants . . 4.33 

4.3.35 Mining | 4.33 

I 

CHAPTER 5. PROBLEMS ASSOCIATED WITH CONDENSED WATER PLUMES .... . 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 Psychrometric Chart . . .\ 5.4 

5.6 Bibliography . 5.8 

i 

CHAPTER 6. LEGAL ASPECTS OF OPACITY OBSERVATIONS ; .1 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 I 6.10 

6.4.4 Type of Information Required in Testimony . . 6.12 

6.5 Bibliography J 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 
m .iWu.» nn I W l 11 IW|l f 

Vll l 

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Zi_.S?. 

7.10 Time Interval Between Readings 7.3 

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 9.0 

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 BJV 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 

10.3 Smokescope : 10.1 

10.6 Photography 10.2 

10.7 TL>. --^photometers 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 11.1 

11.3 Types of Effluent 11.1 

11.3.1 Smoke 11.2 

11.3.2 Fumes 11.3 

11.3.3 Dusts 11.A 

11.3.4 Mists 11.5 

1..3.5 Cases 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 13.1 
., , ,_T _,r (....,. 

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FIGUPE 2.1 

FIGURE 7. .7 

•JIGU^E 3-1 

i;T--:UF'r 3,7 

.•.'T.GURL 3 . •> 

FIGURE 3.^ 

FIGURE 3.5 

FIGURE 3.6 

FIGURE A.1. 

FIGURE 4.2a 

FIG;!PR 4.2b 

FIGUFi 4. J a 

FIGURE 4.3b 

FIGURE ".4 

FIGURF. 4.5 

FI^UKE 4.6 

FIGURE 5..:. 

FIGURE 5.2 

FIGURE 7.J. 

FIGURE 9.1 

TABLE 7.1 

TABLE 9.1 

TABLE 9.2 

TABLE 9.3 

LIST OF FIGURES 

i 

Page 

Smoke School Training Form 2.4 

Car.'.iiicition Letter 2.8' 

•Tr-serv?tion Record (Federal Register) 3.6 

Rcc-orc". o_: Visual Determination of Opacity 

(Federal Register) 3.7 

Visible Emission Observation Form (Proposed) 3.8 

Record of Visual Determination of Opacity (Proposed) . . 3.9. 

Field Sketch 3.14 

Inspection Data Sheet 3.17 

Po-f Monitor Emissions A. 2 

Reck Drilling Emissions 4.4 

Cr'-r.hing Emissions 4.4 

Conveying-Screening Emissions 4.5[ 

otcvage Amissions . 4.5 

Topside View of Coke Battery 4.7 

View of Ovens from Coke Side during Pushing Operations . 4.9 

View of Ovens from Push Side 4.10 

Psychrometric Chart 5.5 

Psychrometric Chart 5.7 

Effect of Observer Location on Observed Pathlength .. . 7.4 

Typical Size Distribution of Particles in the 

Atmosphere Showing Various Average Diameters .... . 9.3 

LIST OF TABLES 

The Beaufort Scale of Wind-Speed Equivalents 2.5 

Variation of Observed Opacity with Distance from 

an Elevated Source 7•-> 

Particle Sizes and Characteristics 9.2 

Size Distribution (% by Number) From Oil Combustion . . . 9.5j 

weight Percent Less than Stated Size From Coal 

Q *v 

Combustion

 y'J 
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T'l' . |-

1.1 

INTRODUCTION 

1.1 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 the 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 regulations, provided the regulations are based on the visual aspect of plumes, 

i 

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-jcreasingly 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 

i 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 particulate 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 complex. The standard, therefore, is most versatile in accomplishing gross 

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. Detjeri mination of opacity and shade of any emission alone gives no specific 

measurements of the quantities of contaminants being emitted. 
P.12 

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 format, 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 • 

.'.. I 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 

l 

visible emissions can be made in the field during enforcement operations, 

i 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 th.. i .eld, 

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, presentation 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 ri^lH angles to the plume 

direction, and from any distance necessary to obtain a 

clear vic^w 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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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 transmissometer location to the stack exit. The two readings 

are therefore taken through approximately the same crosssection 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, handheld 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 nighttime reading a light source is required and the student should be positioned 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. 
P.15 

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 observer'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 
P.16 

ip|i, P|in. 

2.4 

Figure 2.1: NATIONAL ENVIRONMENTAL RESEARCH CENTER 

RESEARCH TRIANGLE PARK, NORTH CAROLINA 

MOKE SCHOOL TRAINING FORM 

1. Name of Observer. 

2. Affiliation 

3. Date rime. 

4. Wind Speed. Direction, Sky Condition. 

5. Observers Position. 

6. Corrected By 

Record Black and/or White Smoke in Percent Opacity (for example: 5 percent smallest division) 

PUN NO. Reading No. 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

Observer 

Reading 

Transmissometer 

Reading 

+ Deviation 

— Deviation 

Reading No. 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

Observer 

Reading 

Transmissoraeter 

Reading 

o 

"ra 

>• 

a> 

Q 

+ — Deviation 

RUN NO. Reading No. 

1 

2 

3 

4 

5 

6 

7 

8 

9' 

10 

11 

12 

Observer 

Reading 

Transmissometer 

Reading 

c_ 

o 

r_ 

> • 

o_ 

Q 

-r 

—Deviation 

Reading No. 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

Observer 

Reading 

Transmissometer 

Reading 

+ Deviation 

—Deviation 

7. Run Number 

8. Number Correct 

9. Number of Plus Deviations 

10. Number of Minus Deviations 

11. Average Plus Deviations = Sum of Plus Deyjiajtions 

No. of P4us Deviations 

12. Average Minus Deviations = Sum o;-f S'intis tjpv-iations 

No. of Minus flreviations 

13. Average Deviation -_ (Sum of Plus psvjattip) + (Sum of Minus Deviations) 

' ToitaFIJJo. of Readings 

14. Number of headings 20% Deviation and Over 

EPA(DUR)255 
2.5 

Table 2.1: THE BEAUFORT SCALE OF WIND-SPEED EQUIVALENTS 

'Tl 

P.17 

General 

Description 

Calm 

Light 

Gentle 

Moderate 

Fresh 

Strong 

Gale 

Whole gale 

Hurricane 

Specifications 

Smoke rises vertically. 

Direction of wind shown by smoke drift 

but not by wind vanes. 

Wind felt on face; leaves rustle; 

ordinary vane moved by wind. 

Leaves and small twigs in constant 

motion; wind extends light flag. 

Raises dust and loose paper; small 

branches are moved. 

Small trees in leaf begin to sway; crested 

wavelets form on inland waters. 

Large branches in motion; whistling heard 

in telegraph wires; umbrellas used with 

difficulty. 

Whole trees in motion; inconvenience felt 

in walking against wind. 

Breaks twigs off trees; generally 

impedes progiess. 

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 mi) 

above level ground 

(MPH) 1 

. i 1 

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 

i 

55 to 63 

i 

64 to 75 

Above 75 
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 "Transmissoraeter 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 

o

1 3-?rve 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 
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 

i 

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 qualification 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 inspector 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" 

i 

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 proi 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 
P.20 

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 untf.l October 7, 1975. 

Sincerely yours, 

Dennis P. Holzschuh 

Physical Science Technician 

Engineering and Enforcement Section 

Air Pollution Training Institute 

Figure 2.2: CERTIFICATION LETTER 
P.21 

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 

i 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. i 

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 training purposes in most states. 

White smoke is usually generated by vaporizing fuel oil in the 

exhaust manifold of a gasoline engine, and black smoke ia 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 procedures are given in Section 12 of this manual. 
P.22 

2.10 

2.9 BIBLIOGRAPHY 

1. Conner, W.D. and J.R. Hodkinson, Optical Properties and Visual 

Effects of Smoke Stack Plumes, DHEW, 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 EVALUATING VISIBLE EMISSIONS IN THE FIELD 

3.I 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 subsequent legal proceedings. 

3.2 OFFICE PREPARATION 

In most instances the inspector will have sufficient notice before i 

making a field observation to adequately prepare for the visit. Preparation 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-r 

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. 
-"-~T -

3.2 

The recommended procedure i.s to determine a vi -

n .-. 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 the 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) Geologists 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 ! 

I 

3.4. 1 GUIDELINES v ' 

I 

The evaluator should select an observation point consistent with j 

the following guidelines: I 

-1

 : 

1) The line of sight from the source to the observer should be . ' 

unobstructed. 

2) The line of sight should bs at right angles to the wind direction. 

3) ' he sun should be oriented within a 140 sector to the observer's 

.,ack. 

4) 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. I 

(See Section 7.9). i 

7) With good visibility it is suggested that the observer should1 

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 emiss ons from rectangular outlets, the observer 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 j 

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 evaluajtion, then the evaluation should be carried out from a location on company 

property. 

i 

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. 
P.26 

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 available 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) Do 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 

J 
• I T 

3 . 5 j 

i 

evaluator's findings should he later be asked about these [ 

conditions during the presentation of testimony. I 

j) Record the name, title and telephone number of the company 

official and note the time that the official was informed j 

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 

i 

3.5.1 OBSERVATION FORMS 

I 

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-jtion of the opacity of emissions, has been finalized, EPA is still considering 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: 

i ,.,i . 
FIGURE 3.1 OBSERVATION RECORD PAGE. .OF. 

COXPANY 

LOCAT.CN 

TEST WS'.lirT 

WTE _ 

OBSERVER 

TYPE FACILITV " ~ 

FOINT CF EMISSlMT 

l-'r. •".In . 

! 0 

I 1 

! _ 

3 

i i 

i 

. . -^ 

7 

3 

" • 

• 1 

1 1? 

! ' 3 

• •_ 

1 16 

i 17 

1 ', •-. 

1 >g 

i ^ 

1 <] .. 

! iH 

1 i 

"i-

•<'> 

'iri 

21 

23 

23 

Seconds 

c : i i : 3D • -5 

' ! 

\ ' ' 

1 : • 

1 ' ' 

! < i 

i > i 

1

 ' ! 

1

 i i 

' ! 1 

! ' 1 

i 

' ! 

I : i 

'

 ! i 

i i 

1 ; l 

i 1 i 

i i 

i i 

I 

i i i 

' ' ' 

'• i ! 

! 1 1 1

 ! 1 

i i i 

1 

! ' 1 1 

STEAM PLUME 

(c^ec'< I f applicable ) 

A;*.scr_d i r;et.Ach»d 

• 

1 

1 

1 

l 

I 

! 

j 

COMMENTS 

OBSERVATION RECORD 

(Continued) 

PAGE CF, 

COMPANY 

LOCATION 

TEST NUXBlT 

OATE 

03SERVD-: 

TYPE FACILITY 

POIIIT OF EM1SSICHT 

Hr. Kin . 

3Q 

31 

32 

Secon.s 

"0 

33 1 

34 

35 

36 

37 

33 

39 

«0 

4) 

42 

<*3 

i'..i 

15 

-5 

<"7 

a o 

49 

50-1 

51 

52 

53 

« 

55 

56 

57 

58 

59 

15 35 

1 

1 

1 

iS 

STEAM Ptu-ie 

(check i f aonlicsble) _ 

AttechcrJ 

1 

1 

1 1 

Detaciod COGENT. 

[FR Dof.74-26150 Filed U-ll-74;6:45 tun] 

FEDERAL REGISTER, VOL 39 , NO. 219—TUESDAY, NOVEMBER I J, 197 4 
FIGURE 3.2 

RECORD OF VISUAL DETERMINATION Of OPACITY PAGE ef 

a 

tn 

5 

COMPANY^ 

LOCATION 

TEST NUMBER. 

DATE 

TYPE FACILITY 

CONTROL DEVICE 

HOURS OF 03SERVATI0N_ 

OBSERVER 

03SERVER CERTIFICATION D." 

OBSERVER AFFILIATION 

POINT OF EMISSIONS 

HEIGifr OF DISCHARGE POINT 

o 

r 

z 

o 

> 

z 

o < 

CLOCK TIME 

OBSERVER LOCATION 

Distance to Discharge 

Direction from Discharge 

Height of Observation Point 

BACKGROUND DESCRIPTION 

WEATHER CONDITIONS 

Kind Direction 

Hind Speed 

Ambient Temperature 

SKY CONDITIONS (clear, 

overcast, % clouds, etc.) 

PLUME DESCRIPTION 

Color 

—Distance-Visible 

OTHER I'lFOOTIOU 

Initial Final SUMMARY OF AVERAGE OPACITY 

Set 

Number 

T'rr. 

Start-End 

Oracity 

S-J.i Average 

Readings ranged from to % opacity 

The source v/as/was not tn conpliance with 

the time evaluation was made. 

at 
P.30 

Figure 3.3: VISIBLE EMISSION OBSERVATION FORM 

Source Name Observer 

Address Date 

Observation Point: 

i 

Stack: Distance From Height 

Wind: Speed Direction 

Sky Condition: 

Color of Emission: 

Ambient Temp: Dry Bulb °F 

Wet Bulb °F 

Relative Humidity: 

Obt, :rvation began Ended 

Observer's 

Signature: 

Certification Date: 

Comments: 

1 1 

" 

1 

o 

1 

2 

3 

4 

5 

6 

7 

8 

9 

IO1 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

0 

29 

15 30 45 

30 

31 

32 

33 

34 

35 

36 

37 

T O 

J O 

39 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

54 

55 

56 

57 

58 

59 

0 15 30 45 

i 
Figure 3.4: RECORD OF VISUAL DETERMINATION OF OPACITY Page of 

COMPANY 

LOCATION 

TEST KUM3F.R 

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 corapletion of, observations -it each source. If observations are made over 

an extended period of time, additional recordings should be made, as applicable 

Clock Time 

Distance to Discharge (ft.) 

Direction from Discharge 

Height of Observation Point (ft.) 

METEOROLOGICAL CONDITIONS: 

Aabient Temp (°F) Dry Bulb/Wet Bulb 

Relative Humidity % 

Wind Direction 

Wind Speed (mph) 

SKY CONDITIONS: 

i Cloud Cover 

PLUME DESCRIPTION: 

Color 

Distance Visible (ft.) 

Other data 

Initial 

^ ^ ^ 

Final 

^ ^ 

SUMMARY OF READINGS 

Opacity 

No. of Readings 

Frequency % 

0-20 21-30 31-40 41-60 61-80 81-100 -Total 

i ! 

i 

1 

Readings over %. Average Opacity = 

Readings ranged from to % opacity. 

Opacity exceeded 

Regulation: 

X for mins 

TJ 
P.32 

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 observed 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 STEAM PLUMES 

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 j 

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. I 

3.5.4.3 RECORDING PRESENCE OF STEAM PLUMES 

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 ti-e suggested alternative forms, Figures 3.3 and 3.4 are used, a 

.ndicating the presence of ar 

be made in the "Comments" section. 

note indicating the presence of an attached or detached steam plume should 

3.5.5 RECORDING OBSERVATIONS ) 

Observations should be made at the point of greatest opacity inithats 

portion of the plume where condensed water vapor is not present. The observer 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 Inumber 

of readings is as follows: 

1) In all cases, a minimum of 24 readings must be taken corresponding 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 regulalation permits 3 minutes of excess emissions in any hour, ; 

a minimum of 12 readings (3 minutes) plus 24 readings (6 i 

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 i 

readings necessary to meet the requirements of Method 9, it is not a 

simple matter to establish the number of readings necessary to document 
P.34 

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 regulal Ion limit, that ;irc_ obnerved, 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 

ttu 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 GUIDELINE 2: 

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 exemption 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 fact, the test results indicate that the chance for positive 

error in determining the opacity of white plumes is essentially non-existent 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. 
!' v JT r'nn 

3.13 

3.5.6.4 GUIDELINE 4: 

The ncluul 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 determine the source that was evaluated and the location of the observation 

i 

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 

i 

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 X 

Postion •*—^-

Date: 

Time: 

Observer: 

Source: 

November 1, 1974 

1400-1500 

Robert Missen 

CGE Power Plant 

Unit 1, Santa Monica, Calif. 

NORTH 

Wind Direction (SE) 

Pico Blvd. 

St. John's 

Church 

Unit 1 Unit 2 

Observer's 

Location 

14th Street 

Power Plant 

Property Line 

Comments: No steam plume visible 

Observation made from St. John's Church parking lot. 

l'lgurt- 3.5: FIELD SKETCH 
T T 

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 acceptable, 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 oyer 

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 thej 

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 of 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. Wei: 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. 
P.39 

- ' - "" - - " ' •' !| II! "II 

3.17 

VISIBLE EMISSIONS EVALUATION DATA SHEET 

OBSERVER: 

DATE: 

COMPANY DATA 

COMPANY NAME: 

COMPANY ADDRESS: 

COMPANY CONTACT: TELEPHONE: 

SOURCE DATA 

SOURCE IDENTIFICATION: 

APPLICABLE R1"-'JLATION: 

OPERATING RATE: 

NORMAL OPERATING RATE: 

CONSTRUCTION/MODIFICATION DATE: 

CONTROL SYSTEM DATA 

TYPE: 

DESIGN EFFICIENCY: 

INSTALLATION DATE: 

COMMENTS: 

Figure 3.6: INSPECTION DATA SHEET 

-
P.40 

T'T W 

4.1 

4. SOURCES OF VISIBLE EMISSIONS 

4.1 INTRODUCTION 

This chapter is divided into two main sections. The first section 

covers emission.s from non-stack sources, for example, coke ovens and equipment 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. Becaus|e 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 are concerned. 

4.2 PROCEDURES FOR NON-STACK EMISSION SOURCES 

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 

Che 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. 
P.41 

4.2 

EMISSIONS 

Roof Monitor 

Figure 4.1: ROOF MONITOR EMISSIONS 
"-' "!"'"l "if'-' 

4. 3 

4.2.2 MATERIAL HANDLING OPERATIONS 

Although the material may vary, the processes involved in the j 

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 released 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 a|t a 

safe distance (e.g. 10-15 feet) from the discharge point, and at thei 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. 
'*F ' ' WW.' P.43 

4.4 

Drilling Rig 

\ 

\ 

V 

EMISSIONS 

Figure 4.2a: ROCK DRILLING EMISSIONS 

Crusher 

./ 

/ 7 

\__Z7 

c. 

EMISSIONS Conveyor 

o o o u ""O" J) 

Figure 4.2b: CRUSHING EMISSIONS 
4.5 

P.44 

o 

Conveyors 

EMISSIONS 

O 

X) 

Hopper 

/ 

EMISSIONS 

EMISSIONS 

Screen _~-— 

EMISSIONS 

Figure 4.3a: CONVEYING-SCREENING EMISSIONS 

EMISSIONS 

Conveyor 

--0 

C7J' 

Figure 4.3b: STORAGE EMISSIONS 
P.45 

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 observation 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) lariry 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. 
4.7 

'T \"V7 

Larry Car x 

Hopper N 

Larry Car Control System 

| 

Standpipe Lid 

Charging Hole 

Figure 4.4: TOPSIDE VIEW OF COKE BATTERY 
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 position on the coke side of the battery, using tha 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-1101, 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 AND 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-
4.9 

,, r T.M-r-M 

Door Removed EMISSIONS 

. 

; i 

i i 

• \ 

! 1 

'. 1 

1 

1

 • ! 

.1, 1 

'!*• ' 

i 

\-

\ 

\ 

! 

i Quench Car 

1

 O O ' 

[•" J.V 

A 

i 

/ 

y> 

• • ' / 

r ,; .J 

1 I 

! I 

! 1 

.1 A 

..... 

1 ._. 

j 

•"I 

I 

! 

i i 

• 

: J..... 

i 

Coke 

Door Removal 

Machine 

Figure 4.5: VIEW OF OVENS FROM COKE SIDE DURING PUSHING OPERATIONS 
4 .10 

P.49 

All Doors Closed 

Leveling Doors Closed 

Figure 4.6: VIEW OF OVENS FROM PUSH SIDE 
P.50 

I i' 

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 S0_ 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. | 

<• i 

Orchard heaters for agricultural purposes are generally under a 

separate category of regulation and are limited to an approved typej 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: 

I 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 (operations; 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 
P.51 

4. 12 

covered storage or in open piles. In the latter case, it is again a potential 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 temperature 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 produce 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 certain amount of entrained, finely divided oil droplets. This results in 

an emissions problem unless some sort of filter or demister is used. 
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! disturbed 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 generated. 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 constitute 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 opentopped 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 temperatures 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. 
py...... — — P-^3_ 

4. IA 

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 ACID MANUFACTURING 

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 
" ' ' r.ii 

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 concentration 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. APJ40, 

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 excessiye 'opacities. 

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 
4.16 

and the crutcher. 

OI.HITV.-IL ions 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, directfired, continuous melting furnaces. Most other types are produced in small 

batch furnaces and are a minor problem compared to soda-lime glass production. 

Silica sand, dry powders, granular oxides, carbonates, cullet 

(broken recycled glass), and other raw materials are transferred from railroad 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 C0_ 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 visible 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. 
P.56 

., n , 

4.17 

REFERENCES: 

Los Angeles County APCD. Air Pollution Engineering Manual. AP-4(p, 

p. 765-782. EPA, Office of Air and Water Programs. 1973.. 

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, 

1

 I 

drying, cooking, baking, frying, boiling, dehydrating, hydrogenating, 

fermenting, distilling, curing, ripening, roasting, broiling, barbecuijng, 

canning, freezing, enriching and packaging. Obviously some produce la'rge 

volumes of visible contaminants and others only insignificant amounts. Two 
FL52L 

4. JH 

of the more troublesome operations wiil 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 essentially no overheating of meal in the drier. 

Observations for these sources may be m^.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 PAINT BAKING 

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 
"'"• T VTT 

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: 

2. 

Los Angeles County APCD. Air Pollution Engineering Manual. AP-40, 

p. 435-531. EPA, Office of Air and Water Programs. 1973. 

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. 
P.59 

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. 
It I -l'j-l 

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 AND GRAVEL 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 1J_ to 2 inches. The undersize 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 problems 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 outlined in Section 4.2, above. 

REFERENCES: 

1. Stern, A., Air Pollution, Volume III. Academic Press, New York. 

p. 123-127. 1968. 

2. Los Angeles County APCD. Air Pollution Engineering Manual. AP-40, 

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. 
P.61 

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 furnace-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. 
P.62 

4.23 

REFERENCES: 

1. Los Angeles County APCD. Air Pollution Engineering Manual. AP-J40, 

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 

; i 

for other reasons, mainly to reduce the possibility of explosions. ,1 

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 productibeing 

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. 
P.63 

4.24 

REFERENCE: 

Los Angeles County APCD. Air Pollution Enginee'ring Manual. AP-40, 

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 ineffic ient 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 ASPHALT ROOFING FELT SATURATORS 

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 condensed 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 

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 materials 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 influences 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 articles 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 :'n the fumes even though they are normally of 

very low vapor pressure. _.'t 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, 
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 waterwash control section they can he 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, the1 electric furnace, or the Bessemer converter. Electric furnaces 

are of three types: direct-arc, indirect-arc and induction. 
• p 

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 submlcronic in size which lends to their very good lightscattering 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: 

i 

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. 
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 sciap 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. 
P.68 

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. j 

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 

These operations are essentially the remelting or re-refining of 

aluminum. Accompanying these, operations are: fluxing, alloying, degasi 

sing and "demagging". The metal in the form of pigs, foundry returns 

or scrap is melted in crucibles,induction furnaces or reverberatory furnaces. 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. 1973i 

4.3.28 SECONDARY ZINC-MELTING PROCESSES 

Zinc is melted in crucible, pot, kettle, reverberatory or electricinduction furnaces as well as in retort and muffle furnaces. Muffle furnaces 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. 
4.30 

The condenser portion i.s 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 malfunction 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. 
P.70 

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. 

4.3.31 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 removal 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 
P.71 

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. Weisburd, 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. 
.,,. r 

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 \ 

i 

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 i Air Pollutant Emission Factors. AP-42, j. 

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. 

I 

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 tp 

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 I 

of Air Programs. 1972.

 ! 
P.73 

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 

i 

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 scattejr 

light and affect the opacity. The droplets formed are in the submicroriic 

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 pllume 

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. 

i 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 revaporize as the plume is transported downwind. Whether 

the 1.1 ume will be attached or detached, and the distance taken for revaporization 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 SOURCES OF 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 enforcement 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 environment that has been occurring in recent years, air pollution agencies 

appear to be receiving increasing numbers of complaints about air pollution emissions from the public. Many of these complaints, concern condensed water vapor plumes which are not covered by air pollution regulations. 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 decreases rapidly from 100% to 0%. For a dry plume containing no condensed 

moisture the opacity is seldom as high as 100%, except under upset conditions, 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 electrostatic precipitator. 
'IT 

5.3 

5.3 READING WATER VAPOR PLUMES 

If the condensed water vapor plume is detached, opacity determinations can be made immediately at the stack exit, i.e. before the water 

I 

vapor begins to condense. I 

.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 jopacity 

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. 
5.4 

3) Relative humidity, which is the ratio of the partial pressureto 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 determine if a condensed water vapor plume is to be formed from a specific 

source if the ambient weather conditions are known. 

Usually the information given (or estimated) is the ambient 

temperature and relative humidity, and the effluent gas temperature and 

moisture content, the latter being defined as the volume percentage of 

water vapor in the effluent gases. 

Knowing the moisture content (M.C) , a value for the humidity ratio 

may be obtained from the following expression: 
*1 

HUO 

c 

H 

nxi 

o ffi 

o 

n 

n 

w 

ro 

tu 

f-1 

ro 

< 

ro 

o 

o 

3 

a 

Hrt 

HO 3 

Cfl p 

H i | 

ft) ; 

*-•_ 

o 

H 

OQ 

fD 

O 

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S'S 

ll..:.l ii:,. . 
P.78 

5.6 

Humidity Ratio = 4354 (M.C.) 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% 

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ratio gives: 

Humidity Ratio = 4354 (0.168) 

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 psychrometric 

chart. A line connecting these two state points crosses the saturation 

curve at about 112 F and 84 F indicating that a condensed water vapor 

plume is a distinct possibility. As the plume mixes with the ambient 

air the water vapor in the plume will begin to condense when the 

effluent temperature reaches 112 F and will begin to revaporize when its 

temperature is further cooled to 84 F. 
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P.80 

5.8 

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 CD . Doyle. Using the Psychrometric Chart. Pollution Engineering, March 1972. 

8. Rohr, F.W. Suppressing Scrubber Steam Plume. Pollution Engineering, 

November 1969. 
6.1 

LEGAL ASPECTS OF OPACITY OBSERVATIONS 

P.81 

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 rat'her 

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 [prohibited the use of coal as detrimental to health, and in 1307 one offender 

w.?s 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 legislature 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 process 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 proper 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 polluT 

tion has seen these major developments since 1907. 
mwi> I. mf^rm v ' • 

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 STANDING 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 regulations cannot be complied with. 

(5) Officers of a corporation may be held responsible for 

actions performed by the corporation. An officer is not 

respQnsible 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 allewed 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. 
nch 

6.3 

6.3 SUMMARY OF COURT CASES , 

The following are summaries of some specific court cases that havej 

given legal standing to the items listed above. 

i 

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 observataon 

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. I 

The Board then appealed this decision to the U.S. Supreme Court which 

ruled unanimously that State authorities are free to make unannounced ii 

spections on the property of suspected air polluters and neither a searwarrant nor advance notice is required for inspections. Justice Douglas, 

in his opinion, also stated that no search warrant is needed for "sightls 

seen in open fields." The court determined that, depending on the layout 

of each plant, the inspection can be made from locations inside or outs|ide 

! 

company premises, in order to be able to make an evaluation from a suitable observation point. 

CASE 2: NORTHWESTERN LAUNDRY VS. DES 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 pollutiojn 

laws. The court decided that: 

1. The Des Moines ordinance declaring the emission of dense smoke 

to be a public nuisance was constitutional. 

i 

2. The Ringelmann Smoke Chart represented a valid method of 

measuring the opacity of emissions. i 

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. 
__-^^_________ _ P.84 

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 the common 

welfare; the only requirement is that the regulation be free from arbitrariness. Northwestern Laundry Co. vs. Des Moines 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. (U.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 Ringelmann 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 prohibition, as far as opacity is concerned cannot be drawn; or if such 

a distinction can be drawn, it is drawn in the wrong place. They 
-,p 

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 tcl3imed 

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 timeithe 

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. 1 

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 

I 

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 

/ ; I 

that the company was responsible for the fire and therefore was liable lin 

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 thie Los Angeles area and was charged with two coun|ts| 

of emitting smoke from boilers in these buildings. It was his contenition, 

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 
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, different, 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 operations 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/J.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 

ihe original judges had not abused their authority by admitting the testimony of inspectors with only two day's training in the evaluation of 
,, I -p., 

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 j 

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 Portland Cement Association vs. Train, Adminlsitrator, 

i 

No. 72-1073 D.C. Cir. May 22, 1975. While this validation of opacity! regulations is binding only for Section 111 purposes, it will serve as .valuable 

precedent for challenge to opacity standards within the State Implementation 

Plans. j 

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 

"l)....were scientifically inaccurate in that they were simply estimates 

obtained by the unaided eyes of field observers, and that the investigai 

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 visuajl 

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. 
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 inadequate 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 arid 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. 
P.89 

. p ...,,. 

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 witness 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. Aftejr 

the oath has been administered he should say "I do" in a loud voice, and 

generally behave in a confident manner. 
P.90 

6.10 

6.4.3 TESTIMONY 

The two main categories of witness testimony is the direct examination 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. g 

8. Did you learn to evaluate black smoke? 

9. Did you learn to evaluate any color other than black? 

10. Did you learn to evaluate 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 
.•,,-,-, ; 

P.91 

7. 

8. 

6.11 

did they end? What were the times, duration and densities of the 

emissions? 

Did you see the source of the erais'sions? 

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. Th|e 

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 deposition or interrogatories. For a deposition the potential witness! is 

placed under oath before a court reporter and asked a wide range of questions 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 
P.92 

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 proceedings 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 INFORMATION REQUIRED IN TESTIMONY 

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, 
. , , ,--:, 

N 

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 I attorney 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 information. 

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 anyi attempt 
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 counsel. 

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 question 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, DHEW, 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 Pollution Control Field Operations Manual, PHS Publication No. 937. 

1962. 

11. Weisburd, M.I. Field Operations and Enforcement Manual for Air 

Pollution Control. APTD-1100, EPA. 1972. 
P.95 

H ! 

7.1 

EFFECTS OF VIEWING CONDITIONS ON OPACITY READINGS 

7.1 WIND SPEED 

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 15- orj 

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 right angles 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 
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 _._.. u-.rted downwind. 

Always read at the point of maximum opacity. For a particulate 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 increasing 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 background 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 background should 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. 
P.97 

•i . |. -|i . • 

7.3 

7.7 ATMOSPHERIC HAZE 

I 

The presence of haze, either natural or man-made, in the atmosphere 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 h 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 direction (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 

l 

produce the lowest opacity reading possible with the existing conditions, 

but it has been found experimentally that the observed opacity is npt 

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 

Figure 7.1: EFFECT OF OBSERVER LOCATION ON OBSERVED PATHLENGTH 
P.99 

T''l V 

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 % 

I 8 

2 

'• 1 

1 

Significant increases in the observed opacity can therefore be introduced 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 

i between the plume and the background decreases, causing a decrease jin 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 

i 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 source the observer should be ajt a 

suitable distance from the source. 

7.10 TIME INTERVAL BETWEEN 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. Thei recommended time interval between readings is 15 seconds. If longer time intervals between readings are taken, the reasons for this should be shown on 

the observation form. 

Read at 15-second time intervals. 
P. 100 

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 Collaborative Study of Method for Determination of Opacity of Emissions 

from Stationary Sources. EPA, Research Triangle Park, N.C. 1975. 
p.l 

V 1 T 

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 

I 

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 a'gency, 

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 trainingf 

and it is not necessary that the observers have an exten- \ 

, i 

sive technical background. Recertification can be achieved 

in one day, or less, every six months. i 

(3) No expensive equipment is required in comparison to alter- , 

native source measurement procedures. 

(4) A qualified inspector can make several observations per day, 

i I enabling a wide area to be inspected, particularly for thos|e 

agencies equipped with a helicopter or light aircraft, , 

allowing potential violators to be quickly located and identified, j 

(5) Violators can be cited without resorting to time-consuming 

and costly source testing. i 

(6) Opacity regulations serve as an effective screening process' 

to reduce the number of expensive source tests required fori 

informational and enforcement requirements. j 

i 

(7) Although it is usually not possible to accurately quantify I 

the reduction in mass emissions by visual observations, there 

is a definite relationship between reducing visible emissions 

;ind improvements in particulate air quality. 
P.2 

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 adjustment, 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: 
__________________________________________________• 

•i | '1 | i I n " -

8.3 

1.1. "The opacity observed is a subjective measurement, varying i 

with the position of the observer in relation to the sun arid 

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 

I 

with other methods of measurement." 

2.2 In recent years several plume opacity models have been developed that, have shown good correlation between predicted and 

observed opacity. The models do require that the input parameters, 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 emicsions, whereas the particles causing light jabsorption 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 regulation 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. 
Ji4_ 

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 nighttime evaluation at the present time. 

5.1 "Water droplets interfere with the equivalent opacity observations." 

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 condensed 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 arbitrary 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 control 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 introduction of dilution air, or by reducing the exit diameter of the 

stack." 
P.5 

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 observations are made according to the approved procedures by a properly qualified inspector the courts will probably continue to accept opacity observations 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 NonBlack 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.,Plume Opacity and Particulate Mass Concentration, 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 Prevention Associations in Washington, D.C. December 1970. 
P.6 

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.H. 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. 
P.7 

9.1 

9. PARTICLE SIZES AND THEIR CHARACTERISTICS 

9.1 GENERAL 

A particle is defined as any dispersed material, either solid!or 

i 

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 7s 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 (Volz.il959) , 

i 

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 addition 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 frpm 

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) 

(min) 

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 

>x> 

hO 

> 

From: Sheehy et al. (1968) 

Tl 

00 
,.,.., (•••Mill ' 

r i 

P.9 

•». ( 

Count Mode (0.619 fi) 

0.4 

c 

o 

(0 

u 

LL, 

0.2 

0.0 

Count Median (1.0//) 

Diameter of Average Mass (2.056 /i) 

Area Median (2.614 A*) 

Area Mean (3.324 H ) 

Mass Median (4.226//) 

Mass Mean 

(51374//) 

Particle Diameter (microns) 

Figure 9.1: TYPICAL SIZE DISTRIBUTION OF PARTICLES IN THE ATMOSPHERE 

SHOWING VARIOUS AVERAGE DIAMETERS (VOLZ, 1959) ' 
P.10 

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 molecular 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 

Municipal 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, Keranitz 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 Wagraan, 1968) 

About 70% by weight<2 microns 

About 90% of lead emissions is contained in particles<0.5 microns 
P.11 

ll'l'l 

9.5 

Fuel Oil Combustion 

The size distribution of particulate emissions from large oil 

burning units Table 9.2, was given by Smith (1962). 

Table 9.2: SIZE DISTRIBUTION (% BY NUMBER) FROM OIL 

COMBUSTION 

Case 

1 

2 

3 

4 

0-1^ 

48.4 

64.2 

93.5 

94.8 

1-2, 

28.8 

18.8 

3.2 

2.2 

2

-

5

„ 

16.7 

10.0 

2.0 

1.5 

>5„ 

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 

i by Smith and Gruber (1966) and are reproduced below in Table 9.3. 

Table 9.3: WEIGHT PERCENT LESS THAN STATED SIZE FROM COAL COMBUSTION 

Particle Size 

ill) 

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) 

' 1 

15 

26 

36 

43 

50 

i 66 

i 

9.3 EFFECT OF ATMOSPHERIC PARTICULATES ON CLIMATE 

Particles in the atmosphere play several roles in the behavior and 

determination of the weather. One of the 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 
P.12 

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 iP increased usage of fossil fuels 

for heating purposes, particularly i_. :'..e 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 OF SOLAR RADIATION 

Solar radiation is attenuated during its passage through the atmosphere 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 
'Tl' | "i'i" 

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 Walkenhorst (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 

i 

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 
P.14 

9.8 

would reach the ground after about 14 minutes. With a wind speed of 5ra/ 

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 atmosphere 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 process is called coagulation. Particles can come into close proximity because 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 gravitational 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. 
P.15 

.,, pn,..-

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 

i 

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 

I 

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. 

3. 

5. 

6. 

Cabe and Atkins, Wind Tunnel Study of Light Absorbance in a 

Dispersing Smoke Plume. Texas Univ. Austin, Dept, 

Civil Eng. Env. Res. Lab., Tech. Dept., EHE-71-5, 

p 80. 1971. 

of 

Chass, R. L. and A. H. Rose. Discharge from Municipal Incinerators. 

Presented at 46th Annual Meeting, Air Pollution Control 

Association. 1953. 

Conner, W. D. and J. Raymond Hodkinson. Optical Properties and 

Visual Effects of Smoke-Stack Plumes, DHEW, PHS 

Publication No. 999-AP-30. 1967. 

Crider, W. L. and J. A. Tash. Study of Vision-""Obscuration by NonBlack Plumes, J. Air Poll. Control Assoc. 14 161-167. 1964. 

Dautrebande, L., H. Bedmann and W. Walkenhorst. Lung Deposition |Of 

Fine Dust Particles. Arch. Ind. Health, Vol. 16, 

pp 179-187. 1957. 

. and M. J. Pilat. Calculation of Smoke Plume Opacity 

from Particulate Air Pollutant Properties, JAPCA, 

p 496. 1971. 

. and M. J. Pilat. Plume Opacity and Particulate Mass 

Concentration, Atmos. Env., 4, p 163-173. 1970. 

. and M. J. Pilat. The Relationship between the 

Visibility and Aerosol Properties of Smoke Stack Plumles, 

Paper presented at the Second International Union of Air 

Pollution Prevention Associations in Washington, D.C.i 1970. 

7. 

8. 

9. 

Ensor, 

Ensor, 

Ensor, 

D. 

D. 

D. 
P.16 

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, APCA, 

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 Characteristics 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. Amer., 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. 
• ; I1 fl" | <;ip -

9.11 

P.17 

26. Mueller, P. K., H. L. Helwig, A. E. Alcocer, 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-56-204/6y 

Air Force Cambridge Research Laboratory, Bedford, Mass. 

1956. ' 

19. 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 Atmosphere1, 

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. 

36. 

37. 

38. 

39. 

40. 

Stoecher, W. 

U. S. Dept. 

Atmospheric Emissions from Fuel Oil Combustion. 

U. S. Dept. of Health, Education and Welfare, 

Publication No. AP-2. 1962. 

F. Smoke Density Measurement, Mech. Eng. 72, 793. 1950. 

of Health, Education and Welfare. Atmospheric Emissions 

from Sulfuric Acid Manufacturing Processes. 

Publication No. AP-2. 1965. 

Van De Hulst, H. C. Light Scattering by Small Particles, John Wiley 

& Sons, Inc., New York. 1957. 

Volz, F. A Photometer for Measurement of Solar Radiation, Arch. 

Met. Geophys. & Bioklimat. B 10, 100-131. 1959. 

Wanta, R. C. Meteorology and Air Pollution, Air Pollution Vol. Ij 

edited by A. C. Stern. 1968. 
P.18 

p-l -:ip -• 

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 

i the source emission. They are simply smaller, hand held Ringelmann charts, 

and should be used to evaluate gray or black emissions. 

10.3 SMOKE INSPECTION GUIDE 

The Public Health Service has developed a film strip comprised bf 

pieces of film with densities of zero, 20, 40, 60 and 80 percent transmission, 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 "costeffectiveness" standpoint for observations in connection with enforcement 

proceedings. 

10.4 COMPARATORS 

These include the smoke tintometer and the umbrascope 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 
P.19 

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 illuminations of the smoke and the reference are both influenced by the same factors. 

Thus, the smokescope is automatically compensated for varying light conditions. (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 transmittance 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 available 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 combination 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 
P.20 

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 resistance 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 backscatter 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 

Collis, Ronald T.H. 

1965. 

Lidar Observation of Cloud, Science 149, 978-981. 

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 AssoCi. 

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 Equivalent 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. 
P.21 

> " rn r "ITI " v • 

11.1 

1 1. 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 pf 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 hkze 

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. 
P.22 

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 described 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. 
P.23 

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 pyroligneoiis 

acid due to sulfide treated paper and wood tar constituents. The blue 

i 

plume contains little or no carbon or soot particles. 

11.3.2 FUME In airS 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, calcilnation 

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 a'nd 

J

 ' | 

metallic oxides and chlorides. Also contained in the fumes are commo;n solid 

I i 

particulates such as fly ash, carbon, mechanically-produced dust and Igases 

such as sulfur dioxide. The fumes principally emitted, however, are |actually 

dusts condensed from the more volatile elements in the metals melted Isuch 

as zinc, sulfur, lead and others. 

Metallurgical operations are the most common form of fume whichi 

consists primarily of the metallic oxide driven from the melting 

surface when metal is heated to the molten state. Metals such as cop'per 

and bronze with relatively high boiling temperatures, as compared to Itheir 

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. 

i 

Some metals may contain alloys with extreme differences in volatility. 

! • 

Copper-based alloys such as yellow brass, manganese bronze, brazing spelter 

and various plumbing metals contain from 14 to 40 percent zinc, the boiling 

temperature of which is around 2200 F. Since the metal must be heatejd to 

melt the copper which has the highest pouring temperature, a portion of the 
11.4 

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 

smoke. 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, sublimation 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 constituent 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 temperature 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 a 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. 
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 micron in diameter and are readily . 

controlled by centrifugal separators, cloth filters and electrostatic1 

precipitators. 

11.3.4 MISTS 

Mists consist of liquid particulates or droplets, less than the1 size 

;>i 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 las 

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 GASES AND 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 

i 

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 
P.26 

11.6 

be made to stop the emissions as soon as possible. 

11.4 * BIBLOGRAPHY 

1. Weisburd, M.I. (Editor), Identifying Effluent Plumes, Air Pollution 

Control Field Operations Manual, PHS Publication No. 937. 1962. 
12.1 

12. METHOD 9 — VISUAL DETERMINATION OF THE OPACITY OF EMISSIONS FROM 

STATIONARY" SOURCES 

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 atmosphere; 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 observers, and procedures to be used in the field for determination of plume 

opacity. The appearance of a plume as viewed by an observer depends upon 

a 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 respect to the plume; angle of the observer with respect to the sun; point 

of observation of attached and detached steam plume; and angle of the 

observer with 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. Howeyer, 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 
P.28 

12.2 

bias decreases rather than increases the possibility that a plant operator 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 sulfuric 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 applicable 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 qualifying 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. 
' "P I 

12.3 

2.1 POSITION 

The qualified observer shall stand at a distance sufficient to provide a clear view of the emissions with the sun oriented in the 140 

sector to his back. 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 rectangular outlets (e.g. roof monitors, open baghouses, noncircular stacks), 

approximately perpendicular to the longer axis of the outlet. The observer's line of sight should not include more than one plume at a time when 

multiple stacks are involved, and in any case the observer should make his 

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. 

i 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 beyond 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. 
P.30 

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 paragraph 3.2. Smoke generators used pursuant to paragraph 3.2 shall be 

equipped with a smoke meter which meets the requirements of paragraph 3.3. 
P.31 

- n 

12.5 

The certification shall be valid for a period of 6 months, at which 

time the qualifica-tion procedure must be repeated by any observer in order 

to retain certification. j 

3-. 2 CERTIFICATION PROCEDURE 

i 

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[ determined. 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 

i 

Any smoke generator used for the purpose of paragraph 3.2 shall be 

equipped with a smoke meter installed to measure opacity across the diameter of the smoke generator stack. The smoke meter output shall dijsplay 

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 

: I 

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 percent opacity, the condition shall be corrected prior to conducting any subsequent 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 replacement of the photocell or associated electronic circuitry including tjhe 

chart recorder or output meter, or every 6 months, whichever occurs first. 
P.32 

12.6 

TABLE 9-1: SMOKE METER DESIGN AND 

PERFORMANCE SPECIFICATIONS 

Parameter 

a. Light sourcefa. Spectral response of photocell 

c. Angle of view 

d. Angle of projection 

e. Calibration errorf. Zero and span drift 

g. Response time 

Specification 

Incandescent lamp operated at nominal 

rated voltage. 

Photopic (daylight spectral response 

of the human eye - reference 4.3). 

-, ,-o , 

15 maximum total angle. 

15 maximum total angle. 

+ 3% opacity, maximum 

+ 1% opacity, 30 minutes. 

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 percent. 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. 
P.33 

r | 

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 

I 

Check construction geometry to ensure that the total angle of1 view 

of the smoke plume, as seen by the photocell, does not exceed 15 . j The 

total angle of view may be calculated from: 6=2 tan d/2L, where 6- total 

angle of view; d=the sum of the photocell diameter + the diameter o|f 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 projection of the lamp on the smoke plume does not exceed 15 . The total 

angle of projection may be calculated from: 6=2 tan d/2L, where 0= total 

angle of projection; ,d=the sum of the length of the lamp filament -If the 

diameter of the limiting aperture; and L=the distance from the lamD to the 

i 

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 neutraldensity 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 readings 

for each filter. The maximum error on any one reading shall be 3 percent 

opacity. 
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, APTD1100, 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;" 
P.35 

13.1 

TECHNICAL REPORT DATA 

(I'lcasc rca.1 tuunn-titiris on thr /nvn v hr/orc ranii'Utini;! 

1. REPORT NO. 

EPA-340/1-75-007 

I. TITL t ANO SUBTITLE 

Guidelines for Evaluation of Visible Emissions 

Certification, Field Procedures, Legal Aspects. 

and Background Material 

7. AUTHOR(S) 

Robert Missen and Arnold Stein 

9. PERFORMING ORGANIZATIO N NAME AND ADDRESS 

Pacific Environmental Services Inc. 

1930 14th Street. 

Santa Monica, California 90404 

1?. SPONSORING AC',1 NCY NAM L AN O ADDRESS 

U. S. Environmental Protection Agency 

Division of Stationary Source Enforcement 

401 M Street SW 

Washington, DC 20460 

3. RECIPIENT'S ACCESSION-NC. 

5. REPORT OATE 

Apri l 1975 * 

6. PERFORMING ORGANIZ AT 1 ONlCODE 

8. PERFORMING ORGANIZATIO N REPORT MO. 

10. PROGRAM ELEMENT NO. 

1 1. CONTRACT/GRAN T NO. 

68-02-1390, Task 2 

13. TYPE OF REPORT AN D PERIOD COVERED 

14. SPONSORING AGENCY 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 evaluationj of nonstack 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 AN D DOCUMENT ANALYSIS 

DESCRIPTORS 

Air Pollution 

Visible Emissions Evaluations 

Plume 

Observations 

Litigation 

Water Vapor 

b.IDENTIFIERS/OPEN ENDED TERMS 

Visible Emissions 

c. COSATI Field/Group 

14B 

14D 

18. DISTRIBUTION STATEMENT 

Unlimited 

19. SECURITY CLASS (This Keporl) 

Unclassified 

20 SECURITY CLASS VvVl/.i/T-X'1) 

Unclassified 

2 1 . NO. OF PAGES 

132, 

EPA Form 2220-1 (9-73>\ 
CO 

co 

ENVIRONMENTAL PROTECTION AGENCY 

Technical Publications Branch 

Office of Administration 

Research Triangle Park, North Carolina 27711 

POSTAGE AND FEES PAID 

ENVIRONMENTAL PROTECTION AGENCY 

EPA - 335 

OFFICIAL BUSINESS 

AN EQUAL OPPORTUNITY EMPLOYER 

Return this sheet if you do NOT wish to receive this material T , 

or if change of address is needed |3J. (Indicate change, including 

ZIP code.) 

PUBLICATION NO. EPA-340/1-75-007 

TSS'