advanced air and noise pollution control

Advanced Air and Noise Pollution Control
Advanced Air and Noise
Pollution Control
Edited by
Lawrence K. Wang, PhD, PE, DEE
Zorex Corporation, Newtonville, NY
Lenox Institute of Water Technology, Lenox, MA
Krofta Engineering Corp., Lenox, MA
Norman C. Pereira, PhD
Monsanto Corporation (Retired), St. Louis, MO
Yung-Tse Hung, PhD, PE, DEE
Department of Civil and Environmental Engineering
Cleveland State University, Cleveland, OH
Consulting Editor
Kathleen Hung Li,
MS
VOLUME 2
H
ANDBOOK OF ENVIRONMENTAL ENGINEERING
© 2005 Humana Press Inc.
999 Riverview Drive, Suite 208
Totowa, New Jersey 07512
humanapress.com
All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted
in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise
without written permission from the Publisher.
All authored papers, comments, opinions, conclusions, or recommendations are those of the author(s), and
do not necessarily reflect the views of the publisher.
For additional copies, pricing for bulk purchases, and/or information about other Humana titles, contact
Humana at the above address or at any of the following numbers: Tel.: 973-256-1699; Fax: 973-256-8341;

E-mail:
This publication is printed on acid-free paper. h
ANSI Z39.48-1984 (American Standards Institute)
Permanence of Paper for Printed Library Materials.
Cover design by Patricia F. Cleary.
Photocopy Authorization Policy:
Authorization to photocopy items for internal or personal use, or the internal or personal use of specific
clients, is granted by Humana Press Inc., provided that the base fee of US $25.00 is paid directly to the
Copyright Clearance Center at 222 Rosewood Drive, Danvers, MA 01923. For those organizations that
have been granted a photocopy license from the CCC, a separate system of payment has been arranged
and is acceptable to Humana Press Inc. The fee code for users of the Transactional Reporting Service is:
[1-58829-359-9/05 $25.00].
eISBN 1-59259-779-3
Printed in the United States of America. 10 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Library of Congress Cataloging-in-Publication Data
Advanced air and noise pollution control / edited by Lawrence K. Wang, Norman C. Pereira, Yung-Tse
Hung ; consulting editor Kathleen Hung Li.
p. cm. — (Handbook of environmental engineering ; v. 2)
Includes bibliographical references and index.
ISBN 1-58829-359-9 (alk. paper) eISBN 1-59259-779-3
1. Air—Pollution. 2. Air quality management. 3. Noise pollution. 4. Noise control. I. Wang,
Lawrence K. II. Pereira, Norman C. III. Hung, Yung-Tse. IV. Handbook of environmental engineering
(2004) ; v. 2.
TD170 .H37 2004 vol. 2
[TD883]
628 s—dc22
[628.5 2003023705
Preface
v

The past 30 years have seen the emergence worldwide of a growing desire to
take positive actions to restore and protect the environment from the degrad-
ing effects of all forms of pollution: air, noise, solid waste, and water. Since
pollution is a direct or indirect consequence of waste, the seemingly idealistic
demand for “zero discharge” can be construed as an unrealistic demand for
zero waste. However, as long as waste exists, we can only attempt to abate the
subsequent pollution by converting it to a less noxious form. Three major ques-
tions usually arise when a particular type of pollution has been identified:
(1) How serious is the pollution? (2) Is the technology to abate it available? and
(3) Do the costs of abatement justify the degree of abatement achieved? The
principal intention of the Handbook of Environmental Engineering series is to help
readers to formulate answers to the last two questions.
The traditional approach of applying tried-and-true solutions to specific
pollution problems has been a major contributing factor to the success of envi-
ronmental engineering, and has accounted in large measure for the establish-
ment of a “methodology of pollution control.” However, realization of the
ever-increasing complexity and interrelated nature of current environmental
problems renders it imperative that intelligent planning of pollution abatement
systems be undertaken. Prerequisite to such planning is an understanding of the
performance, potential, and limitations of the various methods of pollution abate-
ment available for environmental engineering. In this series of handbooks, we
will review at a tutorial level a broad spectrum of engineering systems (pro-
cesses, operations, and methods) currently being utilized, or of potential util-
ity, for pollution abatement. We believe that the unified interdisciplinary
approach in these handbooks is a logical step in the evolution of environmen-
tal engineering.
The treatment of the various engineering systems presented in Advanced Air
and Noise Pollution Control will show how an engineering formulation of the sub-
ject flows naturally from the fundamental principles and theory of chemistry,
physics, and mathematics. This emphasis on fundamental science recognizes that

engineering practice has in recent years become more firmly based on scientific
principles rather than its earlier dependency on the empirical accumulation of facts.
It is not intended, though, to neglect empiricism when such data lead quickly to
the most economic design; certain engineering systems are not readily amenable
to fundamental scientific analysis, and in these instances we have resorted to less
science in favor of more art and empiricism.
Since an environmental engineer must understand science within the con-
text of application, we first present the development of the scientific basis of a
particular subject, followed by exposition of the pertinent design concepts and
operations, and detailed explanations of their applications to environmental
quality control or improvement. Throughout the series, methods of practical
design calculation are illustrated by numerical examples. These examples
clearly demonstrate how organized, analytical reasoning leads to the most
direct and clear solutions. Wherever possible, pertinent cost data have been
provided.
Our treatment of pollution-abatement engineering is offered in the belief that
the trained engineer should more firmly understand fundamental principles, be
more aware of the similarities and/or differences among many of the engineering
systems, and exhibit greater flexibility and originality in the definition and innova-
tive solution of environmental pollution problems. In short, the environmental
engineer should by conviction and practice be more readily adaptable to change
and progress.
Coverage of the unusually broad field of environmental engineering has
demanded an expertise that could only be provided through multiple author-
ships. Each author (or group of authors) was permitted to employ, within rea-
sonable limits, the customary personal style in organizing and presenting a
particular subject area, and consequently it has been difficult to treat all subject
material in a homogeneous manner. Moreover, owing to limitations of space,
some of the authors’ favored topics could not be treated in great detail, and
many less important topics had to be merely mentioned or commented on

briefly. All of the authors have provided an excellent list of references at the
end of each chapter for the benefit of the interested reader. Since each of the
chapters is meant to be self-contained, some mild repetition among the various
texts is unavoidable. In each case, all errors of omission or repetition are the
responsibility of the editors and not the individual authors. With the current
trend toward metrication, the question of using a consistent system of units
has been a problem. Wherever possible the authors have used the British sys-
tem (fps) along with the metric equivalent (mks, cgs, or SIU) or vice versa. The
authors sincerely hope that this doubled system of unit notation will prove
helpful rather than disruptive to the readers.
The goals of the Handbook of Environmental Engineering series are: (1) to cover
the entire range of environmental fields, including air and noise pollution control,
solid waste processing and resource recovery, biological treatment processes,
water resources, natural control processes, radioactive waste disposal, thermal pol-
lution control, and physicochemical treatment processes; and (2) to employ a
multithematic approach to environmental pollution control since air, water, land,
and energy are all interrelated. Consideration is also given to the abatement of
specific pollutants, although the organization of the series is mainly based on the
three basic forms in which pollutants and waste are manifested: gas, solid, and
liquid. In addition, noise pollution control is included in this volume of the hand-
book.
This volume of Advanced Air and Noise Pollution Control, a companion to the
volume, Air Pollution Control Engineering, has been designed to serve as a basic
air pollution control design textbook as well as a comprehensive reference
book. We hope and expect it will prove of equally high value to advanced
undergraduate or graduate students, to designers of air pollution abatement
systems, and to scientists and researchers. The editors welcome comments
from readers in the field. It is our hope that this book will not only provide
information on the air and noise pollution abatement technologies, but will
vi Preface

also serve as a basis for advanced study or specialized investigation of the
theory and practice of the unit operations and unit processes covered.
The editors are pleased to acknowledge the encouragement and support re-
ceived from their colleagues and the publisher during the conceptual stages of
this endeavor. We wish to thank the contributing authors for their time and
effort, and for having patiently borne our reviews and numerous queries and
comments. We are very grateful to our respective families for their patience
and understanding during some rather trying times.
The editors are especially indebted to Dr. Howard E. Hesketh at Southern
Illinois University, Carbondale, Illinois, and Ms. Kathleen Hung Li at NEC
Business Network Solutions, Irving, Texas, for their services as Consulting
Editors of the first and second editions, respectively.
Lawrence K. Wang
Norman C. Pereira
Yung-Tse Hung
Preface vii
ix
Contents
Preface v
Contributors xvii
1 Atmospheric Modeling and Dispersion
Lawrence K. Wang and Chein-Chi Chang 1
1. Air Quality Management 1
2. Air Quality Indices 4
2.1. US EPA Air Quality Index 4
2.2. The Mitre Air Quality Index (MAQI) 5
2.3 Extreme Value Index (EVI) 6
2.4. Oak Ridge Air Quality Index (ORAQI) 8
2.5. Allowable Emission Rates 9
2.6. Effective Stack Height 10

2.7. Examples 11
3. Dispersion of Airborne Effluents 16
3.1. Wind Speed Correction 16
3.2. Wind Direction Standard Deviations 17
3.3. Plume Standard Deviations 17
3.4. Effective Stack Height 17
3.5. Maximum Ground-Level Concentration 18
3.6. Steady-State Dispersion Model (Crosswind
Pollutant Concentrations) 19
3.7. Centerline Pollutant Concentrations 19
3.8. Short-Term Pollutant Concentrations 20
3.9. Long-Term Pollutant Concentrations. 20
3.10. Stability and Environmental Conditions 21
3.11. Air Dispersion Applications 23
Nomenclature 29
References 33
2 Desulfurization and Emissions Control
Lawrence K. Wang, Clint Williford, and Wei-Yin Chen 35
1. Introduction 35
1.1. Sulfur Oxides and Hydrogen Sulfide Emissions 36
1.2. SO
x
Emissions Control Technologies 36
2. Sulfur Oxides and Hydrogen Sulfide Pollution 37
2.1. Acid Rain 37
2.2. Public Health Effects 38
2.3. Materials Deterioration 38
2.4. Visibility Restriction 38
3. US Air Quality Act and SO
x

Emission Control Plan 38
4. Desulfurization Through Coal Cleaning 40
4.1. Conventional Coal Cleaning Technologies 40
4.2. Advanced Coal Cleaning Technologies 41
4.3. Innovative Hydrothermal Desulfurization for Coal Cleaning 44
5. Desulfurization Through Vehicular Fuel Cleaning 45
6. Desulfurization Through Coal Liquefaction,
Gasification, and Pyrolysis 46
6.1. Coal Gasification 46
6.2. Coal Liquefaction 48
6.3. Pyrolysis 49
7. Desulfurization Through Coal-Limestone Combustion 50
7.1. Fluidized-Bed Combustion 50
7.2. Lime–Coal Pellets 51
8. Hydrogen Sulfide Reduction by Emerging Technologies 52
8.1. Innovative Wet Scrubbing Using a Nontoxic
Chelated Iron Catalyst 52
8.2. Conventional Wet Scrubbing Using Alkaline
and Oxidative Scrubbing Solution 53
8.3. Scavenger Adsorption 53
8.4. Selective Oxidation of Hydrogen Sulfide
in Gasifier Synthesis Gas 54
8.5. Biological Oxidation of Hydrogen Sulfide 54
9. “Wet” Flue Gas Desulfurization Using Lime and Limestone 54
9.1. FGD Process Description 55
9.2. FGD Process Chemistry 55
9.3. FGD Process Design and Operation Considerations 58
9.4. FGD Process Modifications and Additives 62
9.5. Technologies for Smelters 64
9.6. FGD Process Design Configurations 65

9.7. FGD Process O&M Practices 74
10. Emerging “Wet” Sulfur Oxide Reduction Technologies 76
10.1. Advanced Flue Gas Desulfurization Process 77
10.2. CT-121 FGD Process 77
10.3. Milliken Clean Coal Technology Demonstration Project 78
11. Emerging “Dry” Sulfur Oxides Reduction Technologies and Others 79
11.1 Dry Scrubbing Using Lime or Sodium Carbonate 79
11.2. LIMB and Coolside Technologies 79
11.3. Integration of Processes for Combined SO
x
and NO
x
Reduction 80
11.4. Gas Suspension Absorbent Process 81
11.5 Specialized Processes for Smelter Emissions:
Advanced Calcium Silicate Injection Technology 82
12. Practical Examples 82
13. Summary 91
Nomenclature 92
References 92
3 Carbon Sequestration
Robert L. Kane and Daniel E. Klein 97
1. Introduction 97
1.1. General Description 97
1.2. Carbon Sequestration Process Description 98
x Contents
2. Development of a Carbon Sequestration Road Map 100
3. Terrestrial Sequestration 101
4. CO
2

Separation and Capture 102
5. Geologic Sequestration Options 105
6. Ocean Sequestration 107
7. Chemical and Biological Fixation and Reuse 108
8. Concluding Thoughts 110
Nomenclature 110
Acknowledgment 110
References 110
4 Control of NO
x
During Stationary Combustion
James T. Yeh and Wei-Yin Chen 113
1. Introduction 113
2. The 1990 Clean Air Act 114
3. NO
x
Control Technologies 115
3.1. In-Furnace NO
x
Control 115
3.2. Postcombustion NO
x
Control 119
3.3. Hybrid Control Systems 120
3.4. Simultaneous SO
2
and NO
x
Control 120
4. Results of Recent Demonstration Plants on NO

x
Control 121
5. Future Regulation Considerations 123
6. Future Technology Developments in Multipollutant Control 123
References 124
5 Control of Heavy Metals in Emission Streams
L. Yu Lin and Thomas C. Ho 127
1. Introduction 127
2. Principle and Theory 128
2.1. Reactions in the Incinerator 128
2.2. Control of Metal Emissions 132
3. Control Device of Heavy Metals 139
3.1. Gravity Settling Chamber 139
3.2. Cyclone 140
3.3. Electrostatic Precipitator 140
3.4. Quench 140
3.5. Scrubber 141
3.6. Fabric Filters 141
3.7. Vitrification 141
3.8. Solidification 142
3.9. Chemical Stabilization and Fixation 142
3.10. Extraction 143
3.11. Fluidized-Bed Metal Capture 143
4. Metal Emission Control Examples 145
4.1. Municipal Solid-Waste Incineration 145
4.2. Asphalt-Treatment Plants 145
4.3. Hazardous Waste Incinerator Operation
at Low-to-Moderate Temperature 147
Nomenclature 148
References 148

Contents xi
6 Ventilation and Air Conditioning
Zucheng Wu and Lawrence K. Wang 151
1. Air Ventilation and Circulation 151
1.1. General Discussion 151
1.2. Typical Applications 153
2. Ventilation Requirements 157
2.1. Rate of Air Change 158
2.2. Rate of Minimum Air Velocity 159
2.3. Volumetric Airflow Rate per Unit Floor Area 159
2.4. Heat Removal 160
3. Ventilation Fans 160
3.1. Type 160
3.2. Fan Laws 163
3.3. Fan Selection to Meet a Specific Sound Limit 166
4. Hood and Duct Design 167
4.1. Theoretical Considerations 167
4.2. Hoods for Cold Processes 171
4.3. Hoods for Hot Processes 174
4.4. Ducts 180
5. Air Conditioning 186
5.1. General Discussion and Considerations 186
5.2. Typical Applications 190
6. Design Examples 193
7. Health Concern and Indoor Pollution Control 206
7.1. Health Effects and Standards 206
7.2. Indoor Air Quality 207
7.3. Pollution Control in Future Air Conditioned Environments 209
8. Heating, Ventilating, and Air Conditioning 210
8.1. Energy and Ventilation 210

8.2. HVAC Recent Approach 213
8.3. HVAC and Indoor Air Quality Control 217
Nomenclature 219
Acknowledgments 220
References 221
Appendix A: Recommended Threshold Limit Values
of Hazardous Substances 223
Appendix B: Tentative Threshold Limit Values
of Hazardous Substances 229
Appendix C: Respirable Dusts Evaluated by Count 230
Appendix D: Converting from Round to Rectangular Ductwork 231
Appendix E: Procedure for Fan Selection
to Meet a Specific Sound Level Limit 231
Appendix F: Method for Determination
of Room Attenuation Effect (RAE) 233
Appendix G: Calculation of a Single-Number Sound-Power Level
Adjusted to “A” Weighted Network (LwA) 234
Appendix H: Determination of Composite Sound Level 234
Appendix I: Noise Absorption Coefficients
of General Building Materials 235
xii Contents
7 Indoor Air Pollution Control
Nguyen Thi Kim Oanh and Yung-Tse Hung 237
1. Indoor Air Quality: Increasing Public Health Concern 237
2. Indoor Air Pollution and Health Effects 238
2.1. Sources of Indoor Air Pollution 238
2.2. Health Effects of Indoor Air Pollutants 240
3. Indoor Air Pollution 253
3.1. Identifying Indoor Air Pollution Problems 253
3.2. Monitoring Indoor Air Quality 254

3.3. Mitigation Measures 255
4. Regulatory and Nonregulatory Measures
for Indoor Air Quality Management 269
References 271
8 Odor Pollution Control
Toshiaki Yamamoto, Masaaki Okubo, Yung-Tse Hung,
and Ruihong Zhang 273
1. Introduction 273
1.1. Sources of Odors 273
1.2. Odor Classification 273
1.3. Regulations 274
1.4. Odor Control Methods 275
2. Nonbiological Method 275
2.1. Emission Control 276
2.2. Air Dilution 284
2.3. Odor Modification 292
2.4. Adsorption Method 295
2.5. Wet Scrubbing or Gas Washing Oxidation 299
2.6. Design Example of Wet Scrubbing or Gas Washing Oxidation 304
2.7. Incineration 307
2.8. Nonthermal Plasma Method 310
2.9. Indirect Plasma Method (Ozone or Radicals Injection) 318
2.10. Electrochemical Method 323
3. Biological Method 325
3.1. Introduction 325
3.2. Biological Control 326
3.3. Working Principles of Biological Treatment Processes 326
3.4. Design of Biofilters 328
Nomenclature 330
References 331

9 Radon Pollution Control
Ali Gökmen, Inci G. Gökmen, and Yung-Tse Hung 335
1. Introduction 335
1.1. Units of Radioactivity 336
1.2. Growth of Radioactive Products in a Decay Series 337
2. Instrumental Methods of Radon Measurement 340
2.1. Radon Gas Measurement Methods 340
Contents xiii
2.2. Radon Decay Product Measurement Methods 343
3. Health Effects of Radon 344
4. Radon Mitigation in Domestic Properties 347
4.1. Source Removal 351
4.2. Contaminated Well Water 351
4.3. Building Materials 352
4.4. Types of House and Radon Reduction 352
References 356
10 Cooling of Thermal Discharges
Yung-Tse Hung, James Eldridge, Jerry R. Taricska,
and Kathleen Hung Li 359
1. Introduction 359
2. Cooling Ponds 360
2.1. Mechanism of Heat Dissipation (Cooling) 360
2.2. Design of Cooling Ponds 361
3. Cooling Towers 370
3.1. Mechanism of Heat Dissipation in Cooling Towers 371
3.2. Types of Towers 371
3.3. Natural Draft Atmospheric Cooling Towers 371
3.4. Natural Draft, Wet Hyperbolic Cooling Towers 373
3.5. Example 1 376
3.6. Hybrid Draft Cooling Towers 376

3.7. Induced (Mechanical) or Forced Draft Wet Cooling Towers 376
3.8. Cooling Tower Performance Problems 380
Nomenclature 381
Glossary 382
Acknowledgment 383
References 383
11 Performance and Costs of Air Pollution Control Technologies
Lawrence K. Wang, Jiann-Long Chen, and Yung-Tse Hung 385
1. Introduction 385
1.1. Air Emission Sources and Control 385
1.2. Air Pollution Control Devices Selection 386
2. Technical Considerations 386
2.1. Point Source VOC Controls 386
2.2. Point Source PM Controls 388
2.3. Area Source VOC and PM Controls 388
2.4. Pressure Drops Across Various APCDs 391
3. Energy and Cost Considerations for Minor Point Source Controls 391
3.1. Sizing and Selection of Cyclones, Gas Precoolers,
and Gas Preheaters 391
3.2. Sizing and Selection of Fans, Ductworks,
Stacks, Dampers, and Hoods 393
3.3. Cyclone Purchase Costs 396
3.4. Fan Purchase Cost 397
3.5. Ductwork Purchase Cost 400
xiv Contents
3.6. Stack Purchase Cost 400
3.7. Damper Purchase Cost 403
4. Energy and Cost Considerations for Major Point Source Controls 404
4.1. Introduction 404
4.2. Sizing and Selection of Major Add-on Air

Pollution Control Devices 404
4.3. Purchased Equipment Costs of Major Add-on
Air Pollution Control Devices 404
5. Energy and Cost Considerations for Area Source Controls 412
5.1. Introduction 412
5.2. Cover Cost 414
5.3. Foam Cost 415
5.4. Wind Screen Cost 415
5.5. Water Spray Cost 415
5.6. Water Additives Costs 416
5.7. Enclosure Costs 416
5.8. Hood Costs 416
5.9. Operational Control Costs 416
6. Capital Costs in Current Dollars 417
7. Annualized Operating Costs 421
7.1. Introduction 421
7.2. Direct Operating Costs 421
7.3. Indirect Operating Costs 426
8. Cost Adjustments and Considerations 428
8.1. Calculation of Current and Future Costs 428
8.2. Cost Locality Factors 428
8.3. Energy Conversion and Representative Heat Values 429
8.4. Construction Costs, O&M Costs, Replacement Costs,
and Salvage Values 430
9. Practice Examples 431
Nomenclature 436
References 438
Appendix: Conversion Factors 440
12 Noise Pollution
James P. Chambers 441

1. Introduction 441
2. Characteristics of Noise 442
3. Standards 443
4. Sources 445
5. Effects 446
6. Measurement 446
7. Control 450
References 452
13 Noise Control
James P. Chambers and Paul Jensen 453
1. Introduction 453
2. The Physics of Sound 454
Contents xv
2.1. Sound 454
2.2. Speed of Sound 454
2.3. Sound Pressure 455
2.4. Frequency 456
2.5. Wavelength 456
2.6. rms Sound Pressure 458
2.7. Sound Level Meter 458
2.8. Sound Pressure Level 458
2.9. Loudness 459
2.10. Sound Power Level 461
2.11. Sound Energy Density 461
3. Indoor Sound 462
3.1. Introduction 462
3.2. Sound Buildup and Sound Decay 464
3.3. Diffuse Sound Field 467
3.4. Reverberation Time 468
3.5. Optimum Reverberation Time 469

3.6. Energy Density and Reverberation Time 469
3.7. Relationship Between Direct and Reflected Sound 470
4. Sound Out-of-Doors 471
4.1. Sound Propagation 471
4.2. Wind and Temperature Gradients 471
4.3. Barriers 472
5. Noise Reduction 473
5.1. Absorptive Materials 473
5.2. Nonacoustical Parameters of Absorptive Materials 479
5.3. Absorption Coefficients 480
6. Sound Isolation 480
6.1. Introduction 480
6.2. Transmission Loss 481
6.3. Noise Reduction 486
6.4. Noise Isolation Class (NIC) 487
7. Vibrations 488
7.1. Introduction 488
7.2. Vibration Isolation 489
8. Active Noise Control 491
9. Design Examples 491
9.1. Indoor Situation 491
9.2. Outdoor Situation 495
Glossary 503
Nomenclature 507
References 508
Index 511
xvi Contents
Contributors
J
AMES

P. C
HAMBERS
,
P
h
D
• National Center for Physical Acoustics and Department
of Mechanical Engineering, University of Mississippi, University, MS
C
HEIN
-C
HI
C
HANG
,
P
h
D
,
PE
• District of Columbia Water and Sewer Authority, Washing-
ton, DC
J
IANN
-L
ONG
C
HEN
,
P

h
D
,
PE
• Department of Civil, Architectural, Agricultural, and Envi-
ronmental Engineering, North Carolina A&T State University, Greensboro, NC
W
EI
-Y
IN
C
HEN
,
P
h
D
• Department of Chemical Engineering, University of Mississippi,
University, MS
J
AMES
E. E
LDRIDGE
,
MS
,
ME
• Lantec Product, Agoura Hills, CA
A
LI
G

ÖKMEN
,
P
h
D
• Department of Chemistry, Middle East Technical University,
Ankara, Turkey
I
NCI
G. G
ÖKMEN
,
P
h
D
• Department of Chemistry, Middle East Technical University,
Ankara, Turkey
T
HOMAS
C. H
O
,
P
h
D
• Department of Chemical Engineering, Lamar University, Beau-
mont, TX
Y
UNG
-T

SE
H
UNG
,
P
h
D
,
PE
,
DEE
• Department of Civil and Environmental Engineering,
Cleveland State University, Cleveland, OH
P
AUL
J
ENSEN
• BBN Technologies, Cambridge, MA
R
OBERT
L. K
ANE
,
MS
• Office of Fossil Energy, U.S. Department of Energy, Washing-
ton, DC
D
ANIEL
E. K
LEIN

,
MBA
• Twenty-First Strategies, LLC, McLean, VA
K
ATHLEEN
H
UNG
L
I
,
MS
• NEC Business Network Solutions, Inc., Irving, TX
L. Y
U
L
IN
,
P
h
D
• Department of Civil and Environmental Engineering, Christian Broth-
ers University, Memphis, TN
N
GUYEN
T
HI
K
IM
O
ANH

, D
R
E
NG
• Environmental Engineering and Management,
School of Environment, Resources and Development, Asian Institute of Technology,
Pathumthani, Thailand
M
ASAAKI
O
KUBO
,
P
h
D
• Department of Energy Systems Engineering, Osaka Prefecture
University, Sakai, Osaka, Japan
N
ORMAN
C. P
EREIRA
,
P
h
D
(
RETIRED
) • Monsanto Company, St. Louis, MO
J
ERRY

R. T
ARICSKA
,
P
h
D
,
PE
• Environmental Engineering Department, Hole Montes, Inc.,
Naples, FL
L
AWRENCE
K. W
ANG
,
P
h
D
,
PE
,
DEE
• Zorex Corporation, Newtonville, NY, Lenox Institute
of Water Technology, Lenox, MA, and Kofta Engineering Corp., Lenox, MA
C
LINT
W
ILLIFORD
,
P

h
D
• Department of Chemical Engineering, University of Mississippi,
University, MS
Z
UCHENG
W
U
,
P
h
D
• Department of Environmental Engineering, Zhejiang University,
Hangzhou, People’s Republic of China
xvii
T
OSHIAKI
Y
AMAMOTO
,
P
h
D
• Department of Energy Systems Engineering, Osaka Prefec-
ture University, Sakai, Osaka, Japan
J
AMES
T. Y
EH
,

P
h
D
• National Energy Technology Laboratory, US Department of Energy,
Pittsburgh, PA
R
UIHONG
Z
HANG
,
P
h
D
• Biological and Agricultural Engineering Department, Univer-
sity of California, Davis, CA
xviii Contributors
1
Atmospheric Modeling and Dispersion
Lawrence K. Wang and Chein-Chi Chang
CONTENTS
AIR QUALITY MANAGEMENT
AIR QUALITY INDICES
DISPERSION OF AIRBORNE EFFLUENTS
NOMENCLATURE
REFERENCES
1. AIR QUALITY MANAGEMENT
Air pollution is the appearance of air contaminants in the atmosphere that can create
a harmful environment to human health or welfare, animal or plant life, or property (1).
In the United States, air pollution is mainly the result of industrialization and urbanization.
In 1970, the Federal Clean Act was passed as Public Law 91-604. The objective of the act

was to protect and enhance the quality of the US air resources so as to promote public
health and welfare and the productive capacity of its population. The Act required that the
administrator of the US Environmental Protection Agency (EPA) promulgate primary and
secondary National Ambient Air Quality Standards (NAAQS) for six common pollutants.
NAAQS are those that, in the judgment of the EPA administrator, based on the air quality
criteria, are requisite to protect the public health (Primary), including the health of sensi-
tive populations such as asthmatics, children, and the elderly, and the public welfare
(Secondary), including protection against decreased visibility, damage to animals, crops,
vegetation, and buildings. These pollutants were photochemical oxidants, particulate
matter, carbon monoxide, nitrogen dioxides, sulfur dioxide, and hydrocarbons.
1. Photochemical oxidants are those substances in the atmosphere that are produced when
reactive organic substances, principally hydrocarbons, and nitrogen oxides are exposed to
sunlight. For the purpose of air quality control, they shall include ozone, peroxyacyl
nitrates, organic peroxides, and other oxidants. Photochemical oxidants cause irritation of
the mucous membranes, damage to vegetation, and deterioration of materials. They affect
the clearance mechanism of the lungs and, subsequntly, resistance to bacterial infection.
The objective of photochemical oxidants’ control is to prevent such effects.
2. A particulate is matter dispersed in the atmosphere, where solid or liquid individual parti-
cles are larger than single molecules (about 2×10
−10
m in diameter), but smaller than about
5 × 10
−4
m. Settleable particulates, or dustfall, are normally in the size range greater than
1
From: Handbook of Environmental Engineering, Volume 2: Advanced Air and Noise P ollution Control
Edited by:L. K. Wang, N. C. Pereira and Y T. Hung © The Humana Press, Inc., Totowa, NJ
2 Lawrence K. Wang and Chein-Chi Chang
10
−5

m, and suspended particulates range below 10
−5
m in diameter. The objective of
suspended particulate control is the protection from adverse health effects, taking into
consideration its synergistic effects.
3. Carbon monoxide is a colorless, odorless gas, produced by the incomplete combustion of
carbonaceous material, having an effect that is predominantly one that causes asphyxia.
4. Nitrogen dioxide is a reddish-orange-brown gas with a characteristic pungent odor. The
partial pressure of nitrogen dioxide in the atmosphere restricts it to the gas phase at usual
atmospheric temperatures. It is corrosive and highly oxidizing and may be physiologically
irritating. The presence of the gas in ambient air has been associated with a variety of res-
piratory diseases. Nitrogen dioxide gas is essential for the production of photochemical
smog. At higher concentrations, its presence has been implicated in the corrosion of elec-
trical components, as well as vegetation damage.
5. Sulfur dioxide is a nonflammable, nonexplosive, colorless gas that has a pungent, irritating
odor. It has been associated with an increase in chronic respiratory disease on long-term
exposure and alteration in lung and other physiological functions on short-term exposure.
6. Hydrocarbons are organic compounds consisting only of hydrogen and carbon. However,
for the purpose of air quality control, hydrocarbons (nonmethane) shall refer to the total
airborne hydrocarbons of gaseous hydrocarbons as a group that have not been associated
with health effects. It has been demonstrated that ambient levels of photochemical oxidant,
which do have adverse effects on health, are associated with the occurrence of concentrations
of nonmethane hydrocarbons.
In 1990, the US Congress passed an amendment to the Clean Air Act of 1970. Under
its requirements, the US EPA is to revise national-health-based standards—National
Ambient Air Quality Standards (NAAQS) as shown in Table 1 (2)—and set the
Significant Harm Levels (SHLs). The Standards, which control pollutants harmful to
people and the environment, were established for six criteria pollutants. These criteria
pollutants are ozone, particulate matter, carbon monoxide, nitrogen dioxides, sulfur
dioxide, heavy metals (especially lead), and various hazardous air pollutants (HAPs).

Descriptions for additional pollutants are described as follows.
Ozone (O
3
) is a gas composed of three oxygen atoms. It is not usually emitted
directly into the air, but at ground level it is created by a chemical reaction between
oxides of nitrogen (NO
x
) and volatile organic compounds (VOCs) in the presence of
heat and sunlight. Ozone has the same chemical structure whether it occurs miles above
the Earth or at ground level and can be “good” or “bad,” depending on its location in
the atmosphere. “Good” ozone occurs naturally in the stratosphere approx 10–30 miles
above the Earth’s surface and forms a layer that protects life on Earth from the sun’s
harmful rays. In the Earth’s lower atmosphere, ground-level ozone is considered “bad.”
Motor vehicle exhaust and industrial emissions, gasoline vapors, and chemical solvents
are some of the major sources of NO
x
and VOCs that contribute to the formation of
ozone. Sunlight and hot weather cause ground-level ozone to form in harmful concen-
trations in the air. As a result, it is known as a summer air pollutant. Many urban areas
tend to have high levels of bad ozone, but even rural areas are also subjected to
increased ozone levels because wind carries ozone and pollutants that form it hundreds
of miles away from their original sources.
Lead is a metal found naturally in the environment as well as in manufactured
products. The major sources of lead emissions have historically been motor vehicles
VOC + NO Heat + Sunlight = Ozone
x
+
Atmospheric Modeling and Dispersion 3
(such as cars and trucks) and industrial sources. Because of the phase out of leaded
gasoline, metals processing is the major source of lead emissions to the air today. The

highest levels of lead in air are generally found near lead smelters. Other heavy metals
in other stationary sources are waste incinerators, utilities, and lead-acid battery man-
ufacturers (4–6).
The list of HAPs and their definitions can be found in ref. 7. New Source Review
(NSR) reform and HAPs control likely will have the most immediate impact on indus-
trial facilities. HAP control will be very active in the 21st century on several fronts—
new regulations, the Maximum Achievable Control Technology (MACT) hammer, and
residual risk. Each presents issues for industrial plant compliance at the present. The
Clean Air Act’s HAP requirements will be a major challenge for any facility that has
the potential to emit major source quantities of HAPs (10 tons/yr of any one HAP or
25 tons/yr of all HAPs combined). It is important to realize that these thresholds apply
to all HAP emissions from an industrial facility, not just the emissions from specific
activities subject to a categorical MACT standard.
In addition to the air quality indices, air effluent dispersion is another air pollution
topic worthy of discussion. In the past decade, there has been a rapid increase in the
height of power plant stacks and in the volume of gas discharged per stack. Although
Table 1
National Ambient Air Quality Standards (NAAQS)
Pollutant Standard value
a
Standard type
Carbon monoxide (CO)
8-h Average 9 ppm (10 mg/m
3
) Primary
1-h Average 35 ppm (40 mg/m
3
) Primary
Nitrogen dioxide (NO
2

)
Annual arithmetic mean 0.053 ppm (100 μg/m
3
) Primary and Secondary
Ozone (O
3
)
1-h Average 0.12 ppm (235 μg/m
3
) Primary and Secondary
8-h Average
b
0.08 ppm (157 μg/m
3
) Primary and Secondary
Lead (Pb)
Quarterly average 1.5 μg/m
3
Primary and Secondary
Particulate (PM 10)
c
Annual arithmetic mean 50 μg/m
3
Primary and Secondary
24-h Average 150 μg/m
3
Primary and Secondary
Particulate (PM 2.5)
c
Annual arithmetic mean

b
15 μg/m
3
Primary and Secondary
24-h Average
b
65 μg/m
3
Primary and Secondary
Sulfur dioxide (SO
2
)
Annual arithmetic mean 0.03 ppm (80 μg/m
3
) Primary
24-h Average 0.14 ppm (365 μg/m
3
) Primary
3-h Average 0.50 ppm (1300 μg/m
3
) Secondary
a
Parenthetical value is an approximately equivalent concentration.
b
The ozone 8-h standard and the PM 2.5 standards are included for information only. A 1999 federal
court ruling blocked implementation of these standards, which the EPA proposed in 1997. The EPA has
asked the US Supreme Court to reconsider that decision. The updated air quality standards can be found at
the US EPA website (2).
c
PM 10: particles with diameters of 10 μm or less; PM 2.5: particles with diameters of 2.5 μm or less.

interest in tall stacks has increased, there is still a lack of proven pollutant (such as sulfur
dioxide) removal devices. Accordingly, air quality control, in part, should continue to
rely on the high stacks for controlling the ground-level pollutant concentrations. The
dispersion of such airborne pollutants, thus, must be monitored and/or predicted. Most
of the mathematical models used for the control of airborne effluents are reported in
a manual, Recommended Guide for the Prediction of the Dispersion of Airborne
Effluents, published by the American Society of Mechanical Engineers (3). In addition
to the models presented for calculating the effective stack height, pollutant dispersion,
and pollutant deposition, the manual also describes meteorological fundamentals,
experimental methods, and the behavior of airborne effluents.
2. AIR QUALITY INDICES
There have been several air quality indices proposed in the past. These indices are
described in the following subsections.
2.1. US EPA Air Quality Index
Initially, the US EPA produced an air quality index known as the Pollutant Standards
Index (PSI) to measure pollutant concentrations for five criteria pollutants (particulate
matter, sulfur dioxide, carbon monoxide, nitrogen dioxide, and ground-level ozone).
The measurements were converted to a scale of 0–500. An index value of 100 was
ascribed to the numerical level of the short-term (i.e., averaging time of 24 h or less)
primary NAAQS and a level of 500 to the SHLs. An index value of 50, which is half the
value of the short-term standard, was assigned to the annual standard or a concentration.
Other index values were described as follows: 0–100, good; 101–200, unhealthful;
greater than 200, very unhealthy. Use of the index was mandated in all metropolitan areas
with a population in excess of 250,000. The EPA advocated calculation of the index
value on a daily basis for each of the four criteria pollutants and the reporting of the
highest value and identification of the pollutant responsible. Where two or more pollu-
tants exceeded the level of 100, although the PSI value released was the one pertaining
to the pollutant with the highest level, information on the other pollutants was also
released. Levels above 100 could be associated with progressive preventive action by state
or local officials involving issuance of health advisories for citizens or susceptible groups

to limit their activities and for industries to cut back on emissions. At a PSI level of 400,
the EPA deemed that “emergency” conditions would exist and that this would require
cessation of most industrial and commercial activity.
In July 1999, the EPA issued its new “Air Quality Index” (AQI) replacing the PSI. The
principal differences between the two indices are that the new AQI does the following:
1. Incorporates revisions to the primary health-based national ambient air quality standards
for ground-level ozone and particulate matter, issued by the EPA in 1977, incorporating
separate values for particulate matter of 2.5 and 10.0 μg (PM
2.5
and PM
10
), respectively.
2. Includes a new category in the index described as “unhealthy for sensitive groups” (index
value of 101–150) and the addition of an optional cautionary statement, which can be used
at the upper bounds of the “moderate” range of the 8-h ozone standard.
3. Incorporates color symbols to represent different ranges of AQI values (“scaled” in the
manner of color topographical maps from green to maroon) that must be used if the index
is reported in a color format.
4 Lawrence K. Wang and Chein-Chi Chang
4. Includes mandatory requirements for the authorities to supply information to the public on
the health effects that may be encountered at the various levels, including a requirement to
report a pollutant-specific sensitive group statement when the index is above 100.
5. Mandates that the AQI shall be routinely collected and that state and local authorities shall
be required to report it, for all metropolitan areas with more than 350,000 people (previ-
ously the threshold was urban areas with populations of more than 200,000).
6. Incorporates a new matrix of index values and cautionary statements for each pollutant.
7. Calculates the AQI using a method similar to that of the PSI—using concentration data
obtained daily from “population-oriented State/Local Air Monitoring Stations (SLAMS)”
for all pollutants except particulate matter (PM).
2.2.The Mitre Air Quality Index (MAQI)

2.2.1. Mathematical Equations of the MAQI
The Mitre Air Quality Index (MAQI) was based on the 1970 Secondary Federal
National Ambient Air Quality Standards (8). The index is the root-sum-square (RSS)
value of individual pollutant indices (9), each based on one of the secondary air quality
standards. This index is computed as follows:
(1)
where I
s
is an index of pollution for sulfur dioxide, I
c
is an index of pollution for carbon
monoxide, I
p
is an index of pollution for total suspended particulates, I
n
is an index of
pollution for nitrogen dioxide, and I
o
is an index of pollution for photochemical oxidants.
These subindices are explained below.
Sulfur Dioxide Index (I
s
): The sulfur dioxide index is the RSS value of individual terms cor-
responding to each of the secondary standards. The RSS value is used to ensure that the index
value will be greater than 1 if one of the standard values is exceeded. The index is defined as
(2)
where C
sa
is the annual arithmetic mean observed concentration of sulfur dioxide, S
sa

is
the annual secondary standard value (i.e., 0.02 ppm or 60 μg/m
3
) consistent with the unit
of measure of C
sa
, C
s24
is the maximum observed 24-h concentration of sulfur dioxide,
S
s24
is the 24-h secondary standard value (i.e., 0.1 ppm or 260 μg/m
3
) consistent with the
unit of measure of C
s24
, C
s3
is the maximum observed 3-h concentration of sulfur dioxide,
S
s3
is the 3-h secondary standard value (i.e., 0.5 ppm or 1300 μg/m
3
) consistent with the
unit of measure of C
s3
, K
1
is 1 if C
s24

≥S
s24
and is 0 otherwise, and K
2
is 1 if C
s3
≥S
s3
and
is 0 otherwise.
Carbon Monoxide Index (I
c
): The carbon monoxide index component of the MAQI is
computed in a fashion similar to the sulfur dioxide index:
(3)
where C
c8
is the maximum observed 8-h concentration of carbon monoxide, S
c8
is the 8-h
secondary standard value (i.e., 9 ppm or 10,000 μg/m
3
) consistent with the unit of measure
of C
c8
, C
c1
is the maximum observed 1-h concentration of carbon monoxide, S
c1
is the 1-h

secondary standard value (i.e., 35 ppm or 40,000 μg/m
3
) consistent with the unit of mea-
sure of C
c1
, and K is 1 if C
c1
≥S
c1
and is 0 otherwise.
ICS KCS
ccc cc
=
()
+
()
[]
88
2
11
2
05.
ICS KCS KCS
ssasa ss ss
=
()
+
()
+
()

[]
2
12424
2
233
2
05.
MAQI =
22222
0.5
IIIII
scpno
++++
[]
Atmospheric Modeling and Dispersion 5
Total Suspended Particulates Index (I
p
): Total suspended particulate concentrations are
always measured in micrograms per cubic meter. The index of total suspended particulates
is computed as
(4)
where C
pa
is the annual geometric mean observed concentration of total suspended partic-
ulate matter. The geometric mean is defined as
(4a)
Because of the nature of a geometric mean, a single 24-h reading of 0 would result in an
annual geometric mean of 0. The EPA recommends that one-half of the measurement
method’s minimum detectable value be substituted (in this case, 0.5 μg/m
3

) when a “zero”
value occurs. S
pa
is the annual secondary standard value (i.e., 60 μg/m
3
), C
p24
is the maxi-
mum observed 24-h concentration of total suspended particulate matter, S
p24
is the 24-h
secondary standard value (i.e., 150 μg/m
3
), and K is 1 if C
p24
≥S
p24
and is 0 otherwise.
Nitrogen Dioxide Index (I
n
): The index of nitrogen dioxide does not require the RSS tech-
nique because only a single annual federal standard has been promulgated. The index is
(5)
where C
na
is the annual arithmetic mean observed concentration of nitrogen dioxide and
S
na
is the annual secondary standard value (i.e., 0.05 ppm or 100 μg/m
3

) consistent with the
unit of measure of C
na
.
Photochemical Oxidants Index (I
o
): The index is computed in a manner similar to the
nitrogen dioxide index. A single standard value is used as the basis of the index, which is
(6)
where C
o1
is the maximum observed 1-h concentration of photochemical oxidants and S
o1
is the 1-h secondary standard value (i.e., 0.08 ppm or 160 μg/m
3
) consistent with the unit
of measure of C
o1
.
2.2.2. Application of the MAQI
A MAQI value of less than 1 indicates that all standards are being met for those pol-
lutants in the MAQI computations. Because nine standards for five pollutants are
involved in computing MAQI, any MAQI value greater than 3 guarantees that at least
one standard value has been exceeded. If the MAQI values to be estimated by Eq. (1)
are based on only five standards for three pollutants, then, for these figures, any MAQI
value greater than 2.24 guarantees that at least one standard has been exceeded.
2.3.Extreme Value Index (EVI)
2.3.1. Mathematical Equations of the EVI
The extreme value index (EVI) was developed by Mitre Corporation (9) for use in
conjunction with the MAQI values. It is an accumulation of the ratio of the extreme

values for each pollutant. The EVIs for individual pollutants are combined using the
RSS method. Only those pollutants are included for which secondary “maximum values
not to be exceeded more than once per year” are defined. The EVI is given by
ICS
ooo
=
[]
11
ICS
nnana
=
gX
i
i
n
n
=
⎡
⎣
⎢
⎤
⎦
⎥
=
∏
1
1
ICS KCS
ppapa pp
=

()
+
()
⎡
⎣
⎢
⎤
⎦
⎥
2
24 24
2
05.
6 Lawrence K. Wang and Chein-Chi Chang
(7)
where E
c
is an extreme value index for carbon monoxide, E
s
is an extreme value index
for sulfur dioxide, E
p
is an extreme value index for total suspended particulates, and E
o
is an extreme value index for photochemical oxidants.
Carbon Monoxide Extreme Value Index (E
c
): The carbon monoxide extreme value is the
RSS of the accumulated extreme values divided by the secondary standard values. The
index is defined as

(8)
where A
c8
is the accumulation of values of those observed 8-h concentrations that exceed
the secondary standard and is expressed mathematically as
(8a)
where K
i
is 1 if (C
c8
)
i
≥S
c8
and is 0 otherwise, S
c8
is the 8-h secondary standard value (i.e.,
9 ppm or 10,000 μg/m
3
) consistent with the unit of measure of the (C
c8
)
i
values, A
c1
is the
accumulation of values of those observed 1-h concentrations that exceed the secondary
standard and is expressed mathematically as
K
i

is 1 if (C
c1
)
i
≥S
c1
and is 0 otherwise, and S
c1
is the 1-h secondary standard value (i.e.,
35 ppm or 40,000 μg/m
3
) consistent with the unit of measure of the (C
c1
)
i
values.
Sulfur Dioxide Extreme Value Index (E
s
): The sulfur dioxide extreme value is computed
in the same manner as the carbon monoxide EVI. This index also includes two terms, one
for each of the secondary standards, which are maximum values, and to be expected more
than once per year. It should be noted that no term is included for the annual standard. The
index is computed as
(9)
where A
s24
is the accumulation of those observed 24-h concentrations that exceed the sec-
ondary standard and is expressed mathematically as
(9a)
where K

i
is 1 if (C
s24
)
i
≥S
s24
and is 0 otherwise, S
s24
is the 24-h secondary standard value
(i.e., 0.1 ppm or 260 mg/m
3
) consistent with the unit of measure of the (C
s24
)
i
values, A
s3
is the accumulation of values of those observed 3-h concentration that exceed the secondary
standard and is expressed mathematically as
where K
i
is 1 if (C
s3
)
i
≥S
s3
and is 0 otherwise, and S
s3

is the 3-h secondary standard value
(i.e., 0.1 ppm or 260 μg/m
3
) consistent with the unit of measure of the (C
s3
)
i
values.
Total Suspended Particulates Extreme Value Index (E
p
): A secondary standard single
maximum value not to be exceeded more than once per year is defined for total suspended
particulates. The total suspended particulates EVI has only one term; no annual term is
included. This index is computed as
AKC
sis
i
i
33
=
()
∑
AKC
sis
i
i
24 24
=
()
∑

EAS AS
sss ss
=
()
+
()
[]
24 24
2
33
2
05.
AKC
cic
i
i
11
=
()
∑
AKC
cic
i
i
88
=
()
∑
EAS AS
ccc cc

=
()
+
()
[]
88
2
11
2
05.
EVI =
2222
EEEE
cspo
+++
[]
05.
Atmospheric Modeling and Dispersion 7
(10)
where A
p24
is the accumulation of those observed 24-h concentrations that exceed the sec-
ondary standard and is expressed mathematically as
where K
i
is 1 if (C
p24
) ≥S
p24
and is 0 otherwise, and S

p24
is the 24-h secondary standard
value (i.e., 150 μg/m
3
).
Photochemical Oxidants Extreme Value Index (E
o
): The index, like the total suspended
particulates index, consists of a single term. The index is calculated as
(11)
where A
o1
is the accumulation of those observed 1-h concentrations that exceed the sec-
ondary standard and is expressed mathematically as
where K
i
is 1 if (C
o1
)
i
≥S
o1
and is 0 otherwise, and S
o1
is the 1-h secondary standard value
(i.e., 0.08 ppm or 160 μg/m
3
) consistent with the unit of measure of the (C
o1
)

i
values.
2.3.2. Application of the EVI
The number or percentage of extreme values provides a meaningful measure of the
ambient air quality because extreme high air pollution values are mostly related to per-
sonal comfort and well-being and affect plants, animals, and property. The EVI and its
component indices always indicate that all standards are not being attained if the index
values are greater than 0. The index value will always be at least 1 if any standards based
on a “maximum value not to be exceeded more than once per year” is surpassed.
It should be noted that the index truly depicts the ambient air quality only if obser-
vations are made for all periods of interest (i.e., 1 h, 3 h, 8 h, and 24 h) during the year
for which secondary standards are defined. Trend analyses using EVI values based on
differing numbers of observations may be inadequate and even misleading.
2.4. Oak Ridge Air Quality Index (ORAQI)
2.4.1. Mathematical Equations of the ORAQI
The Oak Ridge Air Quality Index (ORAQI), which was designed for use with all major
pollutants recognized by the EPA (10), was based on the following formula:
(12)
COEF equals 39.02 when n = 3, and equals 23.4 when n = 5. The concentration of the
pollutants was based on the annual mean as measured by the EPA National Air
Sampling Network (NASN). These are the same data on which the MAQI was based.
The EPA standards used in the calculation were the EPA secondary standards nor-
malized to a 24-h average basis. For SO
2
, the standard used was 0.10 ppm; for NO
2
, it
was 0.20 ppm; and for particulates, it was 150–160 μg/m
3
.

ORAQI = COEF Concentration of Pollutant EPA Standard for Pollutant
3
ii
i
(
)
⎡
⎣
⎢
⎤
⎦
⎥
=
∑
1
096
7
.
AKC
oio
i
i
11
=
()
∑
EAS
ooo
=
11

AKC
pip
i
i
24 24
=
()
∑
EAS
ppp
=
24 24
8 Lawrence K. Wang and Chein-Chi Chang