Disclaimer

This document has been reviewed in accordance with U.S. Environmental

Protection Agency policy and approved for publication. Mention of trade names or

commercial products does not constitute endorsement or recommendation for use.

I-ii
Preface

In 1971, the U.S. Environmental Protection Agency (EPA) promulgated National

Ambient Air Quality Standards (NAAQS) to protect the public health and welfare from

adverse effects of photochemical oxidants. In 1979, the chemical designation of the standards

was changed from photochemical oxidants to ozone (O3). This document focuses primarily

on the scientific air quality criteria for O3 and, to a lesser extent, on those for other

photochemical oxidants such as hydrogen peroxide and the peroxyacyl nitrates.

The EPA promulgates the NAAQS on the basis of scientific information contained

in air quality criteria issued under Section 108 of the Clean Air Act. The previous O3 criteria

document, Air Quality Criteria for Ozone and Other Photochemical Oxidants, was released in

August 1986 and a supplement, Summary of Selected New Information on Effects of Ozone on

Health and Vegetation, was released in January 1992. These documents were the basis for a

March 1993 decision by EPA that revision of the existing 1-h NAAQS for O3 was not

appropriate at that time. That decision, however, did not take into account some of the newer

scientific data that became available after completion of the 1986 criteria document. The

purpose of this revised air quality criteria document for O3 and related photochemical

oxidants is to critically evaluate and assess the latest scientific data associated with exposure

to the concentrations of these pollutants found in ambient air. Emphasis is placed on the

presentation of health and environmental effects data; however, other scientific data are

presented and evaluated in order to provide a better understanding of the nature, sources,

distribution, measurement, and concentrations of O3 and related photochemical oxidants and

their precursors in the environment. Although the document is not intended to be an

exhaustive literature review, it is intended to cover all pertinent literature available through

1995.

This document was prepared and peer reviewed by experts from various state and

Federal governmental offices, academia, and private industry and reviewed in several public

meetings by the Clean Air Scientific Advisory Committee. The National Center for

Environmental Assessment (formerly the Environmental Criteria and Assessment Office) of

EPA’s Office of Research and Development acknowledges with appreciation the contributions

provided by these authors and reviewers as well as the diligence of its staff and contractors in

the preparation of this document at the request of the Office of Air Quality Planning and

Standards.

I-iii

Air Quality Criteria for Ozone

and Related Photochemical Oxidants

Table of Contents

Volume I

1. Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

3. Tropospheric Ozone and Its Precursors . . . . . . . . . . . . . . . . . . . . . . . . 3-1

4. Environmental Concentrations, Patterns, and Exposure Estimates . . . . . . 4-1

Appendix A: Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . A-1

Volume II

5. Environmental Effects of Ozone and Related Photochemical

Oxidants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Appendix A: Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . A-1

Appendix B: Colloquial and Latin Names . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Volume III

6. Toxicological Effects of Ozone and Related Photochemical Oxidants . . . 6-1

7. Human Health Effects of Ozone and Related Photochemical Oxidants . . . 7-1

8. Extrapolation of Animal Toxicological Data to Humans . . . . . . . . . . . . 8-1

9. Integrative Summary of Ozone Health Effects . . . . . . . . . . . . . . . . . . . 9-1

Appendix A: Abbreviations and Acronyms . . . . . . . . . . . . . . . . . . . . . . . . A-1

I-v

Table of Contents

Page

List of Tables ............................................. I-xiii

List of Figures ............................................. I-xviii

Authors, Contributors, and Reviewers ............................. I-xxv

U.S. Environmental Protection Agency Science Advisory Board,

Clean Air Scientific Advisory Committee ......................... I-xxxi

U.S. Environmental Protection Agency Project Team for Development

of Air Quality Criteria for Ozone and Related Photochemical Oxidants .... I-xxxiii

1. EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

1.2 LEGISLATIVE AND REGULATORY BACKGROUND . . . . . . 1-1

1.3 TROPOSPHERIC OZONE AND ITS PRECURSORS . . . . . . . . . 1-2

1.4 ENVIRONMENTAL CONCENTRATIONS, PATTERNS,

AND EXPOSURE ESTIMATES . . . . . . . . . . . . . . . . . . . . . . . 1-9

1.5 ENVIRONMENTAL EFFECTS OF OZONE AND

RELATED PHOTOCHEMICAL OXIDANTS .............. 1-12

1.6 TOXICOLOGICAL EFFECTS OF OZONE AND

RELATED PHOTOCHEMICAL OXIDANTS .............. 1-18

1.7 HUMAN HEALTH EFFECTS OF OZONE AND

RELATED PHOTOCHEMICAL OXIDANTS .............. 1-22

1.8 EXTRAPOLATION OF ANIMAL TOXICOLOGICAL

DATA TO HUMANS ............................... 1-27

1.9 INTEGRATIVE SUMMARY OF OZONE HEALTH

EFFECTS ....................................... 1-28

2. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

2.1 LEGISLATIVE BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . 2-2

2.2 REGULATORY BACKGROUND . . . . . . . . . . . . . . . . . . . . . . 2-2

2.3 SUMMARY OF MAJOR SCIENTIFIC TOPICS

PRESENTED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.3.1 Air Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.3.2 Air Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.3.3 Environmental Effects . . . . . . . . . . . . . . . . . . . . . . . . 2-5

2.3.4 Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

2.4 ORGANIZATION AND CONTENT OF THE DOCUMENT . . . . 2-6

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

3. TROPOSPHERIC OZONE AND ITS PRECURSORS . . . . . . . . . . . . . . 3-1

3.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

I-vii
Table of Contents (cont’d)

Page

3.2 TROPOSPHERIC OZONE CHEMISTRY . . . . . . . . . . . . . . . . . 3-2

3.2.1 Background Information . . . . . . . . . . . . . . . . . . . . . . . 3-2

3.2.2 Structure of the Atmosphere . . . . . . . . . . . . . . . . . . . . 3-3

3.2.2.1 Vertical and Horizontal Mixing in

the Atmosphere . . . . . . . . . . . . . . . . . . . . . . . 3-4

3.2.2.2 Formation of Stratospheric Ozone . . . . . . . . . . 3-4

3.2.3 Background Ozone in the Troposphere . . . . . . . . . . . . . 3-6

3.2.3.1 Tropospheric Hydroxyl Radicals . . . . . . . . . . . 3-7

3.2.3.2 Tropospheric Nitrogen Oxides Chemistry . . . . . 3-8

3.2.3.3 The Methane Oxidation Cycle ............ 3-10

3.2.3.4 Cloud Processes in the Methane-Dominated

Troposphere ......................... 3-15

3.2.4 Photochemistry of the Polluted Atmosphere ......... 3-16

3.2.4.1 Tropospheric Loss Processes of

Volatile Organic Compounds ............. 3-17

3.2.4.2 Chemical Formation of Ozone in Polluted

Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30

3.2.4.3 Hydrocarbon Reactivity with Respect to

Ozone Formation ..................... 3-34

3.2.5 Photochemical Production of Aerosols ............. 3-38

3.2.5.1 Phase Distributions of Organic Compounds . . . 3-38

3.2.5.2 Acid Deposition ...................... 3-40

3.3 METEOROLOGICAL PROCESSES INFLUENCING OZONE

FORMATION AND TRANSPORT ..................... 3-42

3.3.1 Meteorological Processes ...................... 3-42

3.3.1.1 Surface Energy Budgets ................. 3-42

3.3.1.2 Planetary Boundary Layer ............... 3-43

3.3.1.3 Cloud Venting ....................... 3-46

3.3.1.4 Stratospheric-Tropospheric Ozone

Exchange ........................... 3-47

3.3.2 Meteorological Parameters ..................... 3-48

3.3.2.1 Sunlight ............................ 3-48

3.3.2.2 Temperature ......................... 3-49

3.3.2.3 Wind Speed ......................... 3-54

3.3.2.4 Air Mass Characteristics ................ 3-56

3.3.3 Normalization of Trends ....................... 3-58

3.4 PRECURSORS OF OZONE AND OTHER OXIDANTS ....... 3-59

3.4.1 Sources and Emissions of Precursors .............. 3-59

3.4.1.1 Introduction ......................... 3-59

3.4.1.2 Nitrogen Oxides ...................... 3-60

3.4.1.3 Volatile Organic Compounds ............. 3-70

I-viii
Table of Contents (cont’d)

Page

3.4.1.4 Relationship of Summertime Precursor

Emissions and Ozone Production .......... 3-79

3.4.2 Concentrations of Precursor Substances in Ambient

Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-80

3.4.2.1 Nonmethane Organic Compounds .......... 3-81

3.4.2.2 Nitrogen Oxides ...................... 3-84

3.4.2.3 Ratios of Concentrations of Nonmethane

Organic Compounds and Nitrogen Oxides .... 3-85

3.4.3 Source Apportionment and Reconciliation ........... 3-86

3.4.3.1 Source Apportionment .................. 3-86

3.4.3.2 Source Reconciliation .................. 3-89

3.5 ANALYTICAL METHODS FOR OXIDANTS AND

THEIR PRECURSORS .............................. 3-90

3.5.1 Sampling and Analysis of Ozone and Other

Oxidants .................................. 3-90

3.5.1.1 Ozone ............................. 3-90

3.5.1.2 Peroxyacetyl Nitrate and Its Homologues ..... 3-101

3.5.1.3 Gaseous Hydrogen Peroxide .............. 3-105

3.5.2 Sampling and Analysis of Volatile Organic

Compounds ................................ 3-107

3.5.2.1 Introduction ......................... 3-107

3.5.2.2 Nonmethane Hydrocarbons ............... 3-108

3.5.2.3 Carbonyl Species ..................... 3-114

3.5.2.4 Polar Volatile Organic Compounds ......... 3-116

3.5.3 Sampling and Analysis of Nitrogen Oxides ......... 3-117

3.5.3.1 Introduction ......................... 3-117

3.5.3.2 Measurement of Nitric Oxide ............. 3-118

3.5.3.3 Measurements for Nitrogen Dioxide ........ 3-120

3.5.3.4 Calibration Methods ................... 3-126

3.6 OZONE AIR QUALITY MODELS ..................... 3-127

3.6.1 Definitions, Description, and Uses ................ 3-128

3.6.1.1 Grid-Based Models .................... 3-129

3.6.1.2 Trajectory Models ..................... 3-131

3.6.2 Model Components .......................... 3-133

3.6.2.1 Emissions Inventory ................... 3-133

3.6.2.2 Meteorological Input to Air Quality

Models ............................ 3-135

3.6.2.3 Chemical Mechanisms .................. 3-139

3.6.2.4 Deposition Processes ................... 3-140

3.6.2.5 Boundary and Initial Conditions ........... 3-143

3.6.2.6 Numerical Methods .................... 3-143

I-ix
Table of Contents (cont’d)

Page

3.6.3 Urban and Regional Ozone Air Quality Models ....... 3-144

3.6.3.1 The Urban Airshed Model ............... 3-148

3.6.3.2 The Regional Oxidant Model ............. 3-151

3.6.3.3 The Regional Acid Deposition Model ....... 3-154

3.6.4 Evaluation of Model Performance ................ 3-156

3.6.4.1 Model Performance Evaluation

Procedures .......................... 3-157

3.6.4.2 Performance Evaluation of Ozone Air

Quality Models ....................... 3-159

3.6.4.3 Database Limitations ................... 3-160

3.6.5 Use of Ozone Air Quality Models for Evaluating

Control Strategies ........................... 3-162

3.6.6 Conclusions ............................... 3-163

3.7 SUMMARY AND CONCLUSIONS ..................... 3-165

3.7.1 Tropospheric Ozone Chemistry .................. 3-165

3.7.1.1 Ozone in the Unpolluted Atmosphere ....... 3-165

3.7.1.2 Ozone Formation in the Polluted

Troposphere ......................... 3-166

3.7.2 Meteorological Processes Influencing Ozone

Formation and Transport ...................... 3-168

3.7.2.1 Meteorological Processes ................ 3-168

3.7.2.2 Meteorological Parameters ............... 3-168

3.7.2.3 Normalization of Trends ................ 3-169

3.7.3 Precursors ................................. 3-169

3.7.3.1 Volatile Organic Compound Emissions ...... 3-169

3.7.3.2 Nitrogen Oxides Emissions ............... 3-169

3.7.3.3 Concentrations of Volatile Organic

Compounds in Ambient Air ............. 3-170

3.7.3.4 Concentrations of Nitrogen Oxides in

Ambient Air ......................... 3-170

3.7.3.5 Ratios of Concentrations of Nonmethane

Organic Compounds to Nitrogen Oxides ..... 3-171

3.7.3.6 Source Apportionment and Reconciliation .... 3-171

3.7.4 Analytical Methods for Oxidants and Their

Precursors ................................. 3-172

3.7.4.1 Oxidants ........................... 3-172

3.7.4.2 Volatile Organic Compounds ............. 3-173

3.7.4.3 Oxides of Nitrogen .................... 3-174

3.7.5 Ozone Air Quality Models ..................... 3-174

3.7.5.1 Definitions, Descriptions, and Uses ......... 3-174

3.7.5.2 Model Components .................... 3-175

3.7.5.3 Evaluation of Model Performance .......... 3-176

I-x
Table of Contents (cont’d)

Page

3.7.5.4 Use of Ozone Air Quality Model for

Evaluating Control Strategies ............. 3-176

3.7.5.5 Conclusions ......................... 3-176

REFERENCES ......................................... 3-177

4. ENVIRONMENTAL CONCENTRATIONS, PATTERNS, AND

EXPOSURE ESTIMATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

4.1.1 Characterizing Ambient Ozone Concentrations . . . . . . . 4-2

4.1.2 The Identification and Use of Existing Ambient

Ozone Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

4.2 TRENDS IN AMBIENT OZONE CONCENTRATIONS . . . . . . . 4-6

4.3 SURFACE OZONE CONCENTRATIONS ................ 4-14

4.3.1 Introduction ............................... 4-14

4.3.2 Urban Area Concentrations ..................... 4-15

4.3.3 Nonurban Area Concentrations .................. 4-27

4.3.3.1 Sites That Experience Low Maximum Hourly

Average Concentrations ................. 4-27

4.3.3.2 Urban-Influenced Nonurban Areas ......... 4-36

4.4 DIURNAL VARIATIONS IN OZONE CONCENTRATIONS . . . 4-46

4.4.1 Introduction ............................... 4-46

4.4.2 Urban Area Diurnal Patterns .................... 4-47

4.4.3 Nonurban Area Diurnal Patterns ................. 4-51

4.5 SEASONAL PATTERNS IN OZONE CONCENTRATIONS . . . 4-55

4.5.1 Urban Area Seasonal Patterns ................... 4-55

4.5.2 Nonurban Area Seasonal Patterns ................ 4-57

4.5.3 Seasonal Pattern Comparisons with Sites

Experiencing Low Exposures ................... 4-61

4.6 SPATIAL VARIATIONS IN OZONE CONCENTRATIONS .... 4-62

4.6.1 Urban-Nonurban Area Concentration Differences ..... 4-62

4.6.2 Concentrations Experienced at High-Elevation Sites .... 4-62

4.6.3 Other Spatial Variations in Ozone Concentrations ..... 4-65

4.7 INDOOR OZONE CONCENTRATIONS ................. 4-72

4.8 ESTIMATING EXPOSURE TO OZONE ................. 4-73

4.8.1 Introduction ............................... 4-73

4.8.2 Fixed-Site Monitoring Information Used To Estimate

Population and Vegetation Exposure .............. 4-76

4.8.3 Personal Monitors ........................... 4-77

4.8.4 Population Exposure Models .................... 4-78

4.8.5 Concentration and Exposures Used in Research

Experiments ............................... 4-80

I-xi
Table of Contents (cont’d)

Page

4.9 CONCENTRATIONS OF PEROXYACETYL NITRATES IN

AMBIENT ATMOSPHERES .......................... 4-81

4.9.1 Introduction ............................... 4-81

4.9.2 Urban Area Peroxyacetyl Nitrate Concentrations ...... 4-82

4.9.3 Concentration of Peroxyacetyl Nitrate and

Peroxypropionyl Nitrate in Rural Areas ............ 4-83

4.10 CONCENTRATION AND PATTERNS OF HYDROGEN

PEROXIDE IN THE AMBIENT ATMOSPHERE ........... 4-86

4.11 CO-OCCURRENCE OF OZONE ....................... 4-88

4.11.1 Introduction ............................... 4-88

4.11.2 Nitrogen Oxides ............................ 4-89

4.11.3 Sulfur Dioxide ............................. 4-89

4.11.4 Acidic Sulfate Aerosols ....................... 4-90

4.11.5 Acid Precipitation ........................... 4-91

4.11.6 Acid Cloudwater ............................ 4-93

4.12 SUMMARY ...................................... 4-94

REFERENCES ......................................... 4-102

APPENDIX A: ABBREVIATIONS AND ACRONYMS . . . . . . . . . . . . . . . A-1

I-xii
List of Tables

Number Page

2-1 National Ambient Air Quality Standards for Ozone . . . . . . . . . . . 2-3

3-1 Estimated Emissions of Methane, Nonmethane Organic

Compounds, Nitrous Oxide, and Nitrogen Oxides into the

Earth’s Atmosphere from Biogenic and Anthropogenic

Sources .......................................... 3-16

3-2 Calculated Tropospheric Lifetimes of Selected Volatile

Nonmethane Organic Compounds Due to Photolysis and

Reaction with Hydroxyl and Nitrate Radicals and with

Ozone ........................................... 3-19

3-3 Calculated Incremental Reactivities of Selected Volatile

Organic Compounds as a Function of the Volatile Organic

Compound/Nitrogen Oxide Ratio for an Eight-Component

Volatile Organic Compound Mixture and Low-Dilution

Conditions ........................................ 3-37

3-4 Rates of Increase of Peak Ozone with Diurnal Maximum

Temperature for Temperature Less Than 300 K and

Temperature Greater Than 300 K, Based on Measurements

for April 1 to September 30, 1988 ....................... 3-52

3-5 Recent Studies Examining Trends in Ozone Data After Removal of

Variability Associated with Meteorological Factors ............ 3-60

3-6 Source Categories Used To Inventory Nitrogen Oxides

Emissions ........................................ 3-62

3-7 1991 Emission Estimates for Manmade Sources of Nitrogen

Oxides in the United States ............................ 3-63

3-8 Recent Trends in Nitrogen Oxides Emissions for Major

Manmade Source Categories ........................... 3-66

3-9 Comparison of Estimates of Nitrogen Oxides Emissions

from Manmade Sources in the United States ................ 3-68

3-10 Annual Nitrogen Oxides Emissions from Soils by

U.S. Environmental Protection Agency Region .............. 3-69

I-xiii
List of Tables (cont’d)

Number Page

3-11 Estimated 1991 Emissions of Volatile Organic Compounds

from Manmade Sources in the United States ................ 3-71

3-12 Recent Trends in Emissions of Volatile Organic Compounds

from Major Categories of Manmade Sources ................ 3-73

3-13 Annual Biogenic Hydrocarbon Emission Inventory for the

United States ...................................... 3-77

3-14 Annual Biogenic Hydrocarbon Emission Inventory by Month

and by U.S. Environmental Protection Agency Region for

United States Emissions .............................. 3-78

3-15 Performance Specifications for Automated Methods of Ozone

Analysis ......................................... 3-92

3-16 Reference and Equivalent Methods for Ozone Designated

by the U.S. Environmental Protection Agency ............... 3-93

3-17 List of Designated Reference and Equivalent Methods for

Ozone ........................................... 3-94

3-18 Performance Specifications for Nitrogen Dioxide Automated

Methods ......................................... 3-121

3-19 Comparability Test Specifications for Nitrogen Dioxide ........ 3-121

3-20 Reference and Equivalent Methods for Nitrogen Dioxide

Designated by the U.S. Environmental Protection Agency ....... 3-122

3-21 Grid-Based Urban and Regional Air Pollution Models: Overview

of Three-Dimensional Air Quality Models .................. 3-145

3-22 Grid-Based Urban and Regional Air Pollution Models: Treatment

of Emissions and Spatial Resolution ...................... 3-146

3-23 Grid-Based Urban and Regional Air Pollution Models: Treatment

of Meteorological Fields, Transport, and Dispersion ........... 3-147

3-24 Grid-Based Urban and Regional Air Pollution Models: Treatment

of Chemical Processes ............................... 3-149

I-xiv
List of Tables (cont’d)

Number Page

3-25 Grid-Based Urban and Regional Air Pollution Models: Treatment

of Cloud and Deposition Processes ....................... 3-150

3-26 Regional Oxidant Model Geographical Domains ............. 3-152

3-27 Applications of Photochemical Air Quality Models to Evaluating

Ozone ........................................... 3-164

4-1 Ozone Monitoring Season by State . . . . . . . . . . . . . . . . . . . . . . . 4-5

4-2 Summary by Forestry and Agricultural Regions for Ozone Trends

Using the W126 Exposure Parameter Accumulated on a Seasonal

Basis ............................................ 4-13

4-3 The Highest Second Daily Maximum One-Hour Ozone

Concentration by Metropolitan Statistical Area for the Years

1989 to 1991 ...................................... 4-17

4-4 Summary of Percentiles of Hourly Average Concentrations for

the April-to-October Period ............................ 4-20

4-5 The Highest Second Daily Maximum Eight-Hour Average Ozone

Concentration by Metropolitan Statistical Area for the Years

1989 to 1991 ...................................... 4-22

4-6 Seasonal (April to October) Percentile Distribution

of Hourly Ozone Concentrations, Number of Hourly

Mean Ozone Occurrences Greater Than or Equal to 0.08

and Greater Than or Equal to 0.10, Seasonal Seven-Hour

Average Concentrations, W126, and SUM06 Values for Sites

Experiencing Low Hourly Average Concentrations with Data

Capture Greater Than or Equal to 75% .................... 4-30

4-7 Seasonal (April to October) Percentile Distribution

of Hourly Ozone Concentrations, Number of Hourly

Mean Ozone Occurrences Greater Than or Equal to 0.08

and Greater Than or Equal to 0.10, Seasonal Seven-Hour

Average Concentrations, and W126 Values for Three

"Clean" National Forest Sites with Data Capture

Greater Than or Equal to 75% .......................... 4-33

I-xv
List of Tables (cont’d)

Number Page

4-8 The Value of the W126 Sigmoidal Exposure Parameter

Calculated Over the Annual Period ....................... 4-34

4-9 The Value of the Ozone Season (Seven-Month) Average

of the Daily Seven-Hour (0900 to 1559 Hours)

Concentration ...................................... 4-35

4-10 Summary of Percentiles, Number of Hourly Occurrences

Greater Than or Equal to 0.10 ppm, and Three-Month

SUM06 Values for Selected Rural Ozone Monitoring

Sites in 1989 (April to October) ......................... 4-37

4-11 Summary of Percentiles of Hourly Average Concentrations

for Electric Power Research Institute Sulfate Regional

Experiment Program Sites/Eastern Regional Air Quality Study

Ozone Monitoring Sites .............................. 4-38

4-12 Seven-Hour Growing Season Mean, W126 Values, and

Number of Hourly Ozone Concentrations Greater Than or Equal

to 80 ppb for Selected Eastern National Dry Deposition

Network Sites ..................................... 4-40

4-13 Summary of Percentiles for National Dry Deposition

Network Monitoring Sites ............................. 4-41

4-14 Description of Mountain Cloud Chemistry Program

Sites ............................................ 4-63

4-15 Seasonal (April to October) Percentiles, SUM06, SUM08,

and W126 Values for the Mountain Cloud Chemistry

Program Sites ..................................... 4-64

4-16 Summary Statistics for 11 Integrated Forest Study Sites ........ 4-67

4-17 Quarterly Maximum One-Hour Ozone Values at Sites

in and Around New Haven, Connecticut, 1976 ............... 4-69

4-18 Summary of Reported Indoor-Outdoor Ozone Ratios .......... 4-74

4-19 Summary of Measurements of Peroxyacetyl Nitrate and

Peroxypropionyl Nitrate in Urban Areas ................... 4-84

I-xvi
List of Tables (cont’d)

Number Page

4-20 Summary of Measurements of Peroxyacetyl Nitrate and

Peroxypropionyl Nitrate in Rural Areas .................... 4-87

I-xvii
List of Figures

Number Page

3-1 The cyclic reactions of tropospheric nitrogen oxides ........... 3-10

3-2 Atmospheric reactions in the complete oxidation

of methane ....................................... 3-13

3-3 Cyclic reactions of methane oxidation to formaldehyde,

conversion of nitric oxide to nitrogen dioxide, and concomitant

formation of ozone in the atmosphere ..................... 3-15

3-4 Major steps in production of ozone in ambient air ............ 3-31

3-5 Time-concentration profiles for selected species during

irradiations of a nitrogen oxide-propene-air mixture in an

indoor chamber with constant light intensity ................ 3-32

3-6 Time-concentration profiles for selected species during

irradiations of a nitrogen oxide-propene-air mixture in an

outdoor chamber with diurnally varying light intensity ......... 3-32

3-7 Surface radiation budget for short- and long-wave radiation ...... 3-43

3-8 The number of reports of ozone concentrations greater

than or equal to 120 ppb at the 17 cities studied in

Samson and Shi (1988) ............................... 3-50

3-9 A scatter plot of maximum daily ozone concentration in Atlanta,

Georgia, and New York, New York, versus maximum daily

temperature ....................................... 3-51

3-10 A scatter plot of maximum daily ozone concentration in Detroit,

Michigan, and Phoenix, Arizona, versus maximum daily

temperature ....................................... 3-51

3-11 A scatter plot of maximum ozone concentration versus maximum

daily temperature for four nonurban sites .................. 3-52

I-xviii
List of Figures (cont’d)

Number Page

3-12 The frequency of 24-hour trajectory transport distance en route

to city when ozone was greater than or equal to 120 ppb in four

Southern U.S. cities, compared with the percent frequency

distribution for all 17 cities of a nationwide study,

1983 to 1985 ...................................... 3-55

3-13 The frequency of 24-hour trajectory transport distance en route

to city when ozone was greater than or equal to 120 ppb in four

New England cities, compared with the percent frequency

distribution for all 17 cities of a nationwide study,

1983 to 1985 ...................................... 3-55

3-14 The root-mean-square-difference between CLASS

observations and profiler observations as a function of height

above ground level .................................. 3-56

3-15 The root-mean-square-difference between CLASS

observations and lidar observations as a function of height

above ground level .................................. 3-57

3-16 Model of ozone levels using regression techniques ............ 3-58

3-17 Simulated versus observed ozone levels using regression

techniques on an independent data set obtained in the summer of

1992 in Atlanta, Georgia .............................. 3-59

3-18 The 50 largest sources of nitrogen oxides (power plants) in the

United States ...................................... 3-63

3-19 Nitrogen oxides emissions from manmade sources in the

10 U.S. Environmental Protection Agency regions of the

United States, 1991 .................................. 3-64

3-20 Changes in nitrogen oxides emissions from manmade sources in

the United States, 10-year intervals, 1940 through 1990 ........ 3-65

3-21 Changes in nitrogen oxides emissions from stationary source

fuel combustion and transportation from 1940 through

1990 ............................................ 3-66

I-xix
List of Figures (cont’d)

Number Page

3-22 Changes in emissions of volatile organic compounds from major

manmade sources in the United States, 10-year intervals, 1940

through 1990 ...................................... 3-72

3-23 Changes in emissions of volatile organic compounds from major

manmade sources, 1940 through 1990 ..................... 3-73

3-24 Estimated biogenic emissions of volatile organic compounds in

the United States as a function of season ................... 3-80

3-25 Example of Empirical Kinetic Modeling Approach diagram

for high-oxidant urban area ............................ 3-132

3-26 Regional oxidant model superdomain with modeling domains .... 3-153

4-1 National trend in the composite average of the second highest

maximum one-hour ozone concentration at both National Air

Monitoring Stations and all sites with 95% confidence intervals,

1983 to 1992 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

4-2 The annually averaged composite diurnal curves for the following

sites that changed from nonattainment to attainment status:

Montgomery County, Alabama; Concord, California;

Louisville, Kentucky; and Dade County, Florida; for the

period 1987 to 1990 ................................. 4-10

4-3 A summary of the seasonal (January to December) averaged

composite ozone diurnal curve and integrated exposure W126

index for the Los Angeles, California, site for the period 1980

to 1991 .......................................... 4-11

4-4 United States map of the highest second daily maximum one-hour

average ozone concentration by Metropolitan Statistical Area,

1991 ............................................ 4-16

4-5 The relationship between the second highest daily maximum

hourly average ozone concentration and the maximum threemonth SUM06 value and the second highest daily maximum

eight-hour average ozone concentration and the maximum threemonth SUM06 value for specific site years at rural

agricultural sites for the 1980-to-1991 period ................ 4-24

I-xx
List of Figures (cont’d)

Number Page

4-6 The relationship between the second highest daily maximum

hourly average ozone concentration and the maximum threemonth SUM06 value and the second highest daily maximum

eight-hour average ozone concentration and the maximum threemonth SUM06 value for specific site years at rural forested

sites for the 1980-to-1991 period ........................ 4-25

4-7 The location of National Dry Deposition Network monitoring sites

as of December 1990 ................................ 4-39

4-8 The kriged 1985 to 1986 maximum seven-hour and 12-hour

average concentrations of ozone across the United States ....... 4-44

4-9 The kriged estimates of the W126 integrated ozone exposure index

for the eastern United States for 1988 and 1989 .............. 4-45

4-10 The comparison of the seasonal diurnal patterns using 1988 data

for Jefferson County, Kentucky, and Oliver County, North

Dakota .......................................... 4-48

4-11 Diurnal behavior of ozone at rural sites in the United States

in July .......................................... 4-49

4-12 Percent of time hourly average concentrations greater than or equal

to 0.1 ppm occurred between 0900 and 1559 hours in comparison

to 24-hour period for all rural agricultural and forested sites with

three-month SUM06 greater than or equal to 26.4 ppm per hour . . 4-50

4-13 Percent of time hourly average concentrations greater than or equal

to 0.1 ppm occured between 0900 and 1559 hours in comparison

to 24-hour period for all non-California rural agricultural and

forested sites with three-month SUM06 greater than or equal to

26.4 ppm per hour .................................. 4-50

4-14 Diurnal pattern of one-hour ozone concentrations on July 13, 1979,

Philadelphia, Pennsylvania ............................. 4-51

4-15 Diurnal and one-month composite diurnal variations in ozone

concentrations, Washington, District of Columbia, July 1981 ..... 4-52

I-xxi
List of Figures (cont’d)

Number Page

4-16 Diurnal and one-month composite diurnal variations in ozone

concentrations, St. Louis County, Missouri, September 1981 ..... 4-53

4-17 Diurnal and one-month composite diurnal variations in ozone

concentrations, Alton, Illinois, October 1981 (fourth quarter) ..... 4-54

4-18 Composite diurnal patterns of ozone concentrations by quarter,

Alton, Illinois, 1981 ................................. 4-55

4-19 Quarterly composite diurnal patterns of ozone concentrations

at selected sites representing potential for exposure of major

crops, 1981 ....................................... 4-56

4-20 Composite diurnal ozone pattern at a rural National Crop Loss

Assessment Network site in Argonne, Illinois, August 6 through

September 30, 1980 ................................. 4-57

4-21 Composite diurnal ozone pattern at selected National Dry

Deposition Network sites .............................. 4-58

4-22 Composite diurnal pattern at Whiteface Mountain, New York, and

the Mountain Cloud Chemistry Program Shenandoah National

Park site for May to September 1987 ..................... 4-59

4-23 Seasonal variations in ozone concentrations as indicated by

monthly averages and the one-hour maximum in each month at

selected sites, 1981 .................................. 4-60

4-24 Seven- and 12-hour means at Whiteface Mountain and

Shenandoah National Park for May to September 1987 and

integrated exposures at Whiteface Mountain and

Shenandoah National Park for May to September 1987 ......... 4-65

4-25 Integrated exposures for three non-Mountain Cloud Chemistry

Program Shenandoah National Park sites, 1983 to 1987 ........ 4-66

4-26 Number or days in 1991 for which the maximum hourly average

ozone concentration was greater than 0.1 ppm at Chicago,

Illinois .......................................... 4-70

I-xxii
List of Figures (cont’d)

Number Page

4-27 Maximum one-hour ozone concentrations and average 0800 to

2000 hours strong acid concentrations for each day that

pulmonary function data were collected at Fairview Lake

camp in 1988 ...................................... 4-78

4-28 Maximal one-hour ozone concentrations at Fairview Lake during

the study period .................................... 4-79

4-29 The number of occurrences for each of the seven categories

described in text .................................... 4-82

4-30 The co-occurrence pattern of ozone and sulfuric acid for

July 25, 1986, at a summer camp on the north shore of Lake Erie,

Ontario, Canada .................................... 4-91

4-31 Sulfate, hydrogen ion, and ozone measured at Breadalbane Street

(Site 3) in Toronto during July and August, 1986, 1987, and

1988 ............................................ 4-92

I-xxiii

Authors, Contributors, and Reviewers

Chapter 1. Executive Summary

Principal Authors

Mr. James A. Raub—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. William G. Ewald—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. J.H.B. Garner—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Judith A. Graham—National Exposure Research Laboratory (MD-75), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Ms. Beverly E. Tilton—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Chapter 2. Introduction

Principal Author

Mr. James A. Raub—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Chapter 3. Tropospheric Ozone and Its Precursors

Principal Authors

Dr. A. Paul Altshuller—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Roger Atkinson—Statewide Air Pollution Research Center, University of California,

900 Watkins Avenue, Riverside, CA 92521

Mr. Michael W. Holdren—Battelle, 505 King Avenue, Columbus, OH 43201

Dr. Thomas J. Kelly—Battelle, 505 King Avenue, Columbus, OH 43201-2693

I-xxv
Authors, Contributors, and Reviewers (cont’d)

Dr. Charles W. Lewis—National Exposure Research Laboratory (MD-47) U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Perry J. Samson—Department of Atmospheric, Oceanic, and Space Sciences, University of

Michigan, 2455 Hayward Street, Ann Arbor, MI 48109

Dr. John H. Seinfeld—Division of Engineering and Applied Science, California Institute of

Technology, 391 South Holliston Avenue, Pasadena, CA 91125

Dr. Joseph Sickles II—National Exposure Research Laboratory (MD-75), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Ms. Beverly E. Tilton—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Halvor (Hal) Westberg—Department of Civil and Environmental Engineering, Washington

State University, Pullman, WA 99164

Reviewers

Dr. A. Paul Altshuller—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. Robert R. Arnts—National Exposure Research Laboratory (MD-84) U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Frank M. Black—National Exposure Research Laboratory (MD-46), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Joseph J. Bufalini—National Exposure Research Laboratory (MD-84), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Daewon Byun—National Exposure Research Laboratory (MD-80), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Jason K. S. Ching—National Exposure Research Laboratory (MD-80), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Kenneth L. Demerjian—Atmospheric Sciences Research Center (SUNY-Albany),

100 Fuller Road, Albany NY 12205

I-xxvi
Authors, Contributors, and Reviewers (cont’d)

Dr. Robin L. Dennis—National Exposure Research Laboratory (MD-80), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Basil Dimitriades—National Exposure Research Laboratory (MD-75), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Marcia C. Dodge—National Exposure Research Laboratory (MD-84), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Chris D. Geron—National Risk Management Laboratory (MD-62), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Michael W. Gery—Atmospheric Research Associates, 160 North Washington Street,

Boston, MA 02114

Dr. James M. Godowitch—National Exposure Research Laboratory (MD-80),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Jimmie W. Hodgeson—National Exposure Research Laboratory (MD-84),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Harvey E. Jeffries—Department of Environmental Sciences and Engineering, School of

Public Health, CB #7400, University of North Carolina, Chapel Hill, North Carolina

27599-7400

Dr. Douglas R. Lawson—Energy and Environmental Engineering Center, Desert Research

Institute, Reno, NV 89506

Dr. Charles W. Lewis—National Exposure Research Laboratory (MD-47), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. William A. Lonneman—National Exposure Research Laboratory (MD-84),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. William A. McClenny—National Exposure Research Laboratory (MD-44),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. Frank F. McElroy—National Exposure Research Laboratory (MD-77), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Thomas B. McMullen—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

I-xxvii
Authors, Contributors, and Reviewers (cont’d)

Dr. Edwin L. Meyer—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. David C. Misenheimer—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. J. David Mobley—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Will Ollison—American Petroleum Institute, 1220 L Street NW, Washington, DC 20005

Dr. Kenneth Olszyna—Tennessee Valley Authority, CEB 2A, Muscle Shoals, AL 35660

Mr. Thomas E. Pierce—National Exposure Research Laboratory (MD-80), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Larry J. Purdue—National Exposure Research Laboratory (MD-56), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Kenneth A. Rehme—National Exposure Research Laboratory (MD-77),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Harold G. Richter—Private consultant, 8601 Little Creek Farm Road, Chapel Hill, NC

27516

Mr. Shawn J. Roselle—National Exposure Research Laboratory (MD-80), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Kenneth L. Schere—National Exposure Research Laboratory (MD-80),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Jack H. Shreffler—National Exposure Research Laboratory (MD-75), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Dr. Joseph Sickles II—National Exposure Research Laboratory (MD-75), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. Robert L. Seila—National Exposure Research Laboratory (MD-84), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Ms. Beverly E. Tilton—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

I-xxviii
Authors, Contributors, and Reviewers (cont’d)

Dr. Fred Vukovich—Private consultant, 7820 Harps Mill Road, Raleigh, NC 27615

Mr. Richard A. Wayland—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Chapter 4. Environmental Concentrations, Patterns, and

Exposure Estimates

Principal Authors

Dr. Allen S. Lefohn—A.S.L. & Associates, 111 Last Chance Gulch, Suite 4A,

Helena, MT 59601

Dr. A. Paul Altshuller—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Reviewers

Dr. Thomas C. Curran—Office of Air Quality Planning and Standards (MD-12),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. Gary F. Evans—National Exposure Research Laboratory (MD-56), U.S. Environmental

Protection Agency, Research Triangle Park, NC 27711

Mr. William G. Ewald—National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. Warren P. Freas—Office of Air Quality Planning and Standards (MD-14),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Jon Heuss—General Motors Environmental and Energy Staff, 3044 West Grand Blvd.,

Detroit, MI 48202

Dr. Nelson Kelly—Environmental Sciences Department, General Motors Research and

Development Center, Warren, MI 48090

Dr. Paul J. Lioy—Department of Environmental and Community Medicine, UMDNJ-Robert

Wood Johnson Medical School, Piscataway, NY 08854

Mr. Thomas R. McCurdy— National Exposure Research Laboratory (MD-56),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

I-xxix
Authors, Contributors, and Reviewers (cont’d)

Mr. Cornelius J. Nelson—National Exposure Research Laboratory (MD-56),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. William Parkhurst—Tennessee Valley Authority, CEB 2A, Muscle Shoals, AL 35660

Mr. Harvey M. Richmond—Office of Air Quality Planning and Standards (MD-12),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

I-xxx
U.S. Environmental Protection Agency

Science Advisory Board

Clean Air Scientific Advisory Committee

Ozone Review

Chairman

Dr. George T. Wolff—General Motors Corporation, Environmental and Energy Staff,

General Motors Bldg., 12th Floor, 3044 West Grand Blvd., Detroit, MI 48202

Members

Dr. Stephen Ayres—Office of International Health Programs, Virginia Commonwealth

University, Medical College of Virginia, Box 980565, Richmond, VA 23298

Dr. Jay S. Jacobson—Boyce Thompson Institute, Tower Road, Cornell University, Ithaca, NY

14853

Dr. Joseph Mauderly—Inhalation Toxicology Research Institute, Lovelace Biomedical and

Environmental Research Institute, P.O. Box 5890, Albuquerque, NM 87185

Dr. Paulette Middleton—Science & Policy Associates, Inc., Western Office, Suite 140,

3445 Penrose Place, Boulder, CO 80301

Dr. James H. Price, Jr.—Research and Technology Section, Texas Natural Resources

Conservation Commission, P.O. Box 13087, Austin, TX 78711

Invited Scientific Advisory Board Members

Dr. Morton Lippmann—Institute of Environmental Medicine, New York University Medical

Center, Long Meadow Road, Tuxedo, NY 10987

Dr. Roger O. McClellan—Chemical Industry Institute of Toxicology, P.O. Box 12137,

Research Triangle Park, NC 27711

Consultants

Dr. Stephen D. Colome—Integrated Environmental Services, University Tower, Suite 280,

4199 Campus Drive, Irvine, CA 92715

I-xxxi
U.S. Environmental Protection Agency

Science Advisory Board

Clean Air Scientific Advisory Committee

(cont’d)

Dr. A. Myrick Freeman—Department of Economics, Bowdoin College, Brunswick, ME 04011

Dr. Allan Legge—Biosphere Solutions, 1601 11th Avenue, NW, Calgary, Alberta T2N 1H1,

CANADA

Dr. William Manning—Department of Plant Pathology, University of Massachusetts, Amherst,

MA 01003

Dr. D. Warner North—Decision Focus, Inc., 650 Castro Street, Suite 300, Mountain View,

CA 94041

Dr. Frank E. Speizer—Harvard Medical School, Channing Lab, 180 Longwood Avenue,

Boston, MA 02115

Dr. George E. Taylor—Department of Environmental and Resource Sciences, 130 Fleischmann

Agriculture Bldg. 199, University of Nevada, Reno, NV 89557

Dr. Mark J. Utell—Pulmonary Disease Unit, Box 692, University of Rochester Medical

Center, 601 Elmwood Avenue, Rochester, NY 14642

Designated Federal Official

Mr. Randall C. Bond—Science Advisory Board (1400), U.S. Environmental Protection

Agency, 401 M Street, SW, Washington, DC 20460

Staff Assistant

Ms. Lori Anne Gross—Science Advisory Board (1400), U.S. Environmental Protection

Agency, 401 M Street, SW, Washington, DC 20460

I-xxxii
U.S. Environmental Protection Agency

Project Team for Development of Air Quality Criteria

for Ozone and Related Photochemical Oxidants

Scientific Staff

Mr. James A. Raub—Health Scientist, National Center for Environmental Assessment

(MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. A. Paul Altshuller—Physical Scientist, National Center for Environmental Assessment

(MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Mr. William G. Ewald—Health Scientist, National Center for Environmental Assessment (MD52), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. J.H.B. Garner—Ecologist, National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Dr. Judith A. Graham—Associate Director, National Center for Environmental Assessment

(MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Ms. Ellie R. Speh—Secretary, National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Ms. Beverly E. Tilton—Physical Scientist, National Center for Environmental Assessment

(MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Technical Support Staff

Mr. Douglas B. Fennell—Technical Information Specialist, National Center for Environmental

Assessment (MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC

27711

Mr. Allen G. Hoyt—Technical Editor and Graphic Artist, National Center for Environmental

Assessment (MD-52), U.S. Environmental Protection Agency, Research Triangle Park, NC

27711

Ms. Diane H. Ray—Technical Information Manager (Public Comments), National Center for

Environmental Assessment (MD-52), U.S. Environmental Protection Agency, Research

Triangle Park, NC 27711

I-xxxiii
U.S. Environmental Protection Agency

Project Team for Development of Air Quality Criteria

for Ozone and Related Photochemical Oxidants

(cont’d)

Mr. Richard N. Wilson—Clerk, National Center for Environmental Assessment (MD-52),

U.S. Environmental Protection Agency, Research Triangle Park, NC 27711

Document Production Staff

Ms. Marianne Barrier—Graphic Artist, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Mr. John R. Barton—Document Production Coordinator, ManTech Environmental Technology,

Inc., P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Lynette D. Cradle—Word Processor, ManTech Environmental Technology, Inc., P.O. Box

12313, Research Triangle Park, NC 27709

Ms. Shelia H. Elliott—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Sandra K. Eltz—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Jorja R. Followill—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Sheila R. Lassiter—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Wendy B. Lloyd—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Carolyn T. Perry—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. Cheryl B. Thomas—Word Processor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Mr. Peter J. Winz—Technical Editor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

I-xxxiv
U.S. Environmental Protection Agency

Project Team for Development of Air Quality Criteria

for Ozone and Related Photochemical Oxidants

(cont’d)

Technical Reference Staff

Mr. John A. Bennett—Bibliographic Editor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

Ms. S. Blythe Hatcher—Bibliographic Editor, Information Organizers, Inc., P.O. Box 14391,

Research Triangle Park, NC 27709

Ms. Susan L. McDonald—Bibliographic Editor, Information Organizers, Inc., P.O. Box 14391,

Research Triangle Park, NC 27709

Ms. Carol J. Rankin—Bibliographic Editor, Information Organizers, Inc., P.O. Box 14391,

Research Triangle Park, NC 27709

Ms. Deborah L. Staves—Bibliographic Editor, Information Organizers, Inc., P.O. Box 14391,

Research Triangle Park, NC 27709

Ms. Patricia R. Tierney—Bibliographic Editor, ManTech Environmental Technology, Inc.,

P.O. Box 12313, Research Triangle Park, NC 27709

I-xxxv