Independent Workshop on Ozone NAAQS Science and Policy


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Pre-Workshop Webinar & Background Materials


In preparation for the workshop, a two part webinar was held for the expert panelists and speakers.  Drs. Julie Goodman and Sonja Sax of Gradient, along with Dr. Sabine Lange of TCEQ, presented background information on key ozone topics that will be discussed at the workshop. All attendees are encouraged to view this webinar and/or the slides prior to the workshop.

Lists of References from the Webinar Presentations

Webinar Introduction



Discussion of NAAQS and other causality frameworks and how they are applied to ozone



Overview of Mode of Action and discussion of thresholds



Overview of controlled exposure studies and adversity



Overview of key epidemiology literature


  • Julie E. Goodman, Ph.D., DABT, ACE, ATS, Gradient
    • Slides
    • No Recording available


Impacts of using ambient ozone concentrations as surrogates for personal exposure


  • Sonja Sax, Sc.D., Gradient
    • Slides
    • No Recording Available


Integrating evidence streams together


  • Julie E. Goodman, Ph.D., DABT, ACE, ATS, Gradient
    • Slides
    • No Recording Available


Other Background Materials


McClellan RO. 2011. Role of science and judgment in setting national ambient air quality standards: how low is low enough? Air Qual Atmos Health, 5:243–258. Available at

This paper describes the challenges faced in setting NAAQS under the Clean Air Act.



Summary Information on Selected Science Topics Related to Ozone
Prepared by Sabine Lange, TCEQ, and Julie Goodman and Sonja Sax of Gradient.

This document contains summaries of important topics for understanding ozone science. It includes discussions about ozone mode of action, human clinical studies, adverse effects, epidemiology, exposure, a history of the ozone National Ambient Air Quality Standard (NAAQS), and information about the NAAQS causal framework. These particular topics are included in this document because, in the authors opinion, these data are important to inform the choice of the level of the ozone NAAQS. This document was



Ozone-FEV1 Dose-Response Analysis
Prepared by Sabine Lange and Michael Honeycutt, TCEQ; and Ge Tao, Lorenz Rhomberg and Julie Goodman, Gradient

This presents an analysis of the ozone-forced expiratory volume in 1 second (FEV1) dose-response data, derived from human clinical ozone exposure experiments. This analysis produces a dose-response model that fits both healthy young adults and other populations, such as children and asthmatics. We calculated ozone thresholds at which specific group mean FEV1 decrements would be expected to occur, and also determined the number of people in the clinical experiments that experienced a greater-than-mean response to ozone at these thresholds. We compared these thresholds to the doses of ozone a person would be expected to attain during known exposure scenarios, given eight-hour maximum ambient ozone concentrations of 75, 70, or 65 parts per billion (ppb).



Lange et al. 2014. How dose-response curves derived from clinical ozone exposures can inform public policy. Poster presented at 2014 Society for Risk Analysis Annual Meeting, Denver, CO. December 8.

This poster reports on an analysis of how dose-response curves from human clinical studies of ozone can be used to inform the choice of a protective ambient ozone concentration. This is a companion piece to the ozone-FEV1 dose response analysis.



Goodman et al., 2014. Evaluation of Study Quality Criteria Frameworks. Poster presented at 2014 Society for Risk Analysis Annual Meeting, Denver, CO. December 8.

This poster reports on a critical evaluation of study quality criteria frameworks and identifies the most common and useful criteria for evaluating the quality of studies used to assess potential causal relationships between chemicals and health effects.



EPA Ozone Information

EPA Ground Level Ozone Web Page


Ozone Proposed Rule (2014)
Available at:
I A. Executive Summary
II E. Conclusions on the elements of the primary standard – particularly part D: Administrator’s proposed conclusions on level (pp.75303 – 75310).


Final Ozone Integrated Science Assessment (2013)
Available at:
The following sections may be of interest for the workshop:

Chapter 3 – Atmospheric Chemistry & Ambient Concentrations

    • 3.2 (pp.3-1 – 3-22) – Physical and chemical processes – includes photochemical formation of ozone in the stratosphere and trophosphere; anthropogenic emissions of ozone precursors
    • 3.4 (pp.3-40 – 3-61) – Background ozone concentrations – discusses ozone contributions from natural and anthropogenic sources; models for estimating background concentrations

Chapter 4 – Exposure to Ambient Ozone

    • 4.3 (pp. 4-4 – 4-30) – Exposure measurement – includes personal monitoring; relationships between indoor, outdoor and ambient measurements.
    • 4.4 (pp.4-30 – 4-43) – Exposure-related metrics – includes activity patterns

Chapter 5 – Dosimetry, Mode of Action & Species Homology

    • 5.2 (pp.5-2 – 5-28) – Human and animal ozone dosimetry – includes ozone uptake, ozone reactions and reaction products
    • 5.3 (pp. 5-28 – 5-51) – Possible pathways/modes of action – discusses activation of neural reflexes; inflammation; altered epithelial barrier function; sensitization of bronchial smooth muscle; modification of immune responses; airways remodeling

Chapter 6 – Integrated Health Effects of Short-term Ozone Exposure

    • 6.2 (pp.6-1 – 6-165) – Respiratory effects – includes lung function; airway hyper-responsiveness; inflammation; respiratory symptoms and medication use; hospital admissions, emergency department visits; respiratory mortality; causal determination
    • 6.6 (pp.6-220 – 6-260) – Mortality – includes associations of mortality and short-term ozone exposure; causal determination

Chapter 7 – Integrated Health Effects of Long-term Ozone Exposure

    • 7.2 (pp.7-2 – 7-36)- Respiratory effects – includes new-onset asthma; asthma hospital admissions and emergency department visits; respiratory mortality
    • 7.7 (pp.7-85 – 7-90) – Mortality