1

TECHNICAL AND POLICY ISSUES 

PROPOSED OZONE NAAQS 

August 2, 2010

Presentation to: Robert Sussman

Senior Policy Counsel

U.S. Environmental Protection Agency

Washington, D.C. 
2

Maintain current 2013 ozone review schedule

 Review new health studies to address unanswered questions on 

health effects from the last review

 Review new data on ozone background levels and significant impact 

on health benefits valuation

 Review new data on international transport and potential impacts on 

SIPs

 Assess utility and applicability of a secondary standard in the W126 

form

 The above recommendations can be accomplished by folding this 

unscheduled review into the scheduled ozone review now underway. 

Key Recommendations
3

Background

 EPA reconsidering 2008 NAAQS decision

 Outstanding issues with 2008 decision not resolved

 EPA now proposes 0.060 - 0.070 ppm standard based on:

 The scientific record from the last review

 Provisional Assessment (PA) of more recent studies

 EPA concluded that PA does not “materially change“ the conclusions 

on health effects made in the 2007 (AQCD) Criteria Document

 A comprehensive review of new studies suggests an alternate 

conclusion
4

Concerns with Health Studies from Last Review

 Reanalyzed published studies, reaching different conclusions 

 Excluded well conducted studies without justification

 Relied on conflicting hypothesis to explain inconsistent results

 Used individual responses within a group clinical study

 Failed to recognize limitations of observational studies

 Deviated from established medical criteria for adverse effect
5

Recent Studies Suggest Alternative Conclusions

 EPA concluded pulmonary function effects at 0.060 ppb

 New clinical study confirms no effects at 0.060 ppm 

 EPA claimed asthma exacerbation at current ozone levels

 3 of 4 new studies report no association

 EPA concluded airway inflammation/respiratory morbidity at current 

levels

 All new studies (3) on airway inflammation report no association

 Results of new studies on respiratory morbidity are mixed 

 EPA concluded cardiac admissions at current levels

 7 of 8 new studies in PA report no association 

 EPA concluded acute mortality at current levels

 New studies do not support case for acute mortality link 
6

 EPA defines PRB as ozone levels that would occur in the absence 

of anthropogenic emissions in North America

 EPA asserts PRB to be 15-35 ppb based on GEOS-CHEM modeling

 Modeled PRB is far too low in comparison to monitored values

 Risk assessment uses ozone in excess of PRB in benefits valuation

Policy Relevant Background (PRB)
7

EPA CASTNET DATA INDICATE LEVELS IN MANY RURAL AREAS 

WILL EXCEED A 60-70 ppb NAAQS1

1VValues are three-Year Average of Fourth Highest Daily Maximum 8-Hour Average Ozone Concentrations (ppb)

in various National Parks for 2006–2008

Yellowstone 

Rocky Mt. 

Acadia 

Blackwater 

Great Smokey

Kane National Forest

Big Bend Monmouth Cave 

Lassen

Volcano 

Yosemite 

Petrified Forest

Grand Canyon 

Sequoia 

Joshua Tree 

Konza Prairie
8

International Transport Impacts U.S.1

 Increasing Asia emissions are outpacing U.S. reductions

 Asia emissions contribute up to 17 ppb to tropospheric ozone

 Trend projected to continue at 0.7 ppbv per year

 Intrusion increases ground level ozone in the west and mid-west 

 Key conclusion: ozone transport hindering attainment in U.S.

1Statements, data, conclusions presented are from Cooper et al. (2010). 
9

Impact of PRB on Acute Mortality Estimates1

Number of Deaths 

Attributable to Ozone > 

GEOS-CHEM PRB

Number of Deaths 

Attributable to Ozone > 

40 ppb PRB

Percent Reductions If 

Using 40 ppb rather 

than GEOS-CHEM for 

PRB Assumption

Atlanta 6.5 0.3 95%

Cleveland 37.4 4.3 88%

Detroit 37.9 1.8 95%

Houston 22.7 1.5 94%

Los Angeles 38.5 0.1 >99

Sacramento 11.0 0.2 98%

St. Louis 4.4 0.3 93%

1Risks estimated using risk specific coefficients from Bell et al. 2004, at exact attainment of the 0.084 ppm NAAQS, average of 2002 and 2004 data (CRA, 

2007) 
10

A Separate Secondary NAAQS Not Warranted

 Little new evidence of secondary effects

 W126 index lacks a strong biological basis

 Peer-reviewed research concluded W126 greatly overestimated the 

negative response to ozone

 CASAC recommends ”EPA collect information and seek additional 

research that could be used to inform continued refinement of the 

[W126] standard”

 W126 standard is not ready for national implementation
11

Conclusions

 Do not change the standards without a full review of the new health 

studies and without correcting background ozone levels.

 EPA should maintain current 2013 ozone review schedule

 New / existing health studies do not support lower standard

 The benefits of a lower ozone NAAQS are highly uncertain 

 Majority of studies show no effects at current levels

 Low modeled PRB over-stated benefit valuation

 A lower NAAQS will vastly increase non-attainment areas preventing 

business expansion, negatively impacting jobs..... 

 W126 secondary standard is not ready for national implementation 
12

Background
13
14

EPA Data Show Lowest 10% Ozone Values Have Remained 

Relatively Flat Despite Aggressive Control Program

Year 10th Percentile

1980 0.069

1981 0.070

1982 0.069

1983 0.072

1984 0.071

1985 0.069

1986 0.070

1987 0.074

1988 0.077

1989 0.070

1990 0.070

1991 0.068

1992 0.068

1993 0.066

1994 0.069

1995 0.072

1996 0.071

1997 0.066

1998 0.071

1999 0.072

2000 0.067

2001 0.069

2002 0.069

2003 0.069

2004 0.064

2005 0.065

2006 0.064

2007 0,061

2008 0.064 http://www.epa.gov/airtrends/ozone.html
Lower NAAQS Drives Extreme Classifications

239

146

111 27 8

0 50 100 150 200 250 300

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

Arkansas

258

187

125 29 33

0 50 100 150 200 250 300

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

Colorado

739

379

111 229 39

0 100 200 300 400 500 600 700 800

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

Illinois

805

384

149 184 51

0 100 200 300 400 500 600 700 800 900

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

677

343

119 164 61

0 100 200 300 400 500 600 700 800

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

Ohio

Pennsylvania

291

146

96 29 22

0 50 100 150 200 250 300 350

2005 Historical

2020 Baseline

2020 for 60 ppb

Thousand Tons of NOx

Emissions EPA "Unknown" Controls EPA "Known" Controls

West Virginia

Source: NERA analysis of EPA data in Docket No. EPA-HQ-OAR-2007-0225 15
16

References

Adams W. et al. (2006). Comparison of chamber 6.6-h exposures to 0.04-0.08 ppm ozone via square-wave and triangular 

Profiles on pulmonary responses. Inhal. Toxicol. 8(2):127-136.

Cooper et al. (2010). Increasing springtime ozone mixing ratios in the free troposphere over western North America.

Nature 463: 344-348. 

Delfino et al. (2002). Association of asthma symptoms with peak particulate air pollution and effect modification by 

Anti-inflammatory medication use. Env. Health Persp. 110(10:607-617.

Fiore et al. (2009). Multi-model estimates for intercontinental transport of ozone pollution in the northern hemisphere (and uncertainties therein), 

presentation January 21, 2009, http://www.gfdl.noaa.gov/cms-filesystem-action/user_files/aff/presentation_ppts/fiore_gfdl_jan09.ppt

HEI (2009). Air Pollution and Health: a European and North American Approach (APHENA). HEI Report 142. 

Kamps A. et al. (2001). Peak flow diaries in childhood asthma are unreliable. Thorax 56:180-182 

Mortimer et al. (2002). The effect of air pollution on inner-city children with asthma. Eur. Resp. J. 19:699-705. 

O’Connor et al. (2008). Acute respiratory health effects of air pollution on children with asthma in U.S. inner cities. J. 

Allergy Clin. Immunol. 12: 1133-9

Schelegle et al. (2009). 6.6 Hour inhalation of ozone concentrations from 60 to 87 ppb in health humans. Am. J. Resp. Crit. Care Med. 164:505-517. 

Smith et al. (1999). Threshold dependence of mortality effects for fine and coarse particles in Phoenix, Arizona. J. Air Waste Management 

Association 50: 1467-1379. 

Schildcdrout et al. (2006). Ambient air pollution and asthma in children: an eight city analysis. Am. J. Epi. 164(5): 505-17. 

Smith et al. (2009). Reassessing the relationship between ozone and short-term mortality in U.S. urban communities. 

Inhalation Toxicology 29:37-61. 

Stoeckenius et al. (2010, 2010). Air quality modeling study for the four corners region and addendum. Environ Int. Corp Report. August 2009 and 

January 2010. http://www.nmenv.state.nm.us/aqb/4c/Modeling.htlm. 

Stylinaou and Nicolich (2009). Cumulative effects and threshold levels in air pollution mortality: data analysis of nine large

US cities using the NMMAPS dataset. Environmental Pollution 157:2216-2223.