Summary of Interagency Working Comments on Draft Language under 

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Health Effects Information

 Page 48. For consistency with the controlled-exposure studies cited in the previous 

paragraph, please provide information about the ozone concentration levels typical 

in these studies. Can these studies detect effects of reducing concentrations from 75 

ppb to 70 ppb, for example? That is, would predicting hospital admissions and 

emergency department visits require an out-of-sample extrapolation of the 

statistical model? These questions are answered later in the preamble, and the 

purpose of adding this information here would be to conform with the preceding 

paragraph.

 Pg 62-63. It would be helpful to understand in more detail the scientifically relevant 

surrogate for health effects outcomes for people with heart and lung disease as it 

applies to healthy people and the severity of these effects. Additionally, it would be 

helpful to understand better how EPA extrapolates from samples of healthy 

volunteers to get the proportion of healthy individuals that are likely to experience 

clinically meaningful changes in lung function following exposure. Please provide 

interagency reviewers with a copy of the new studies referenced at the bottom of 

page 62 and bottom of page 63.

 Page 92. Please be more precise in this section about the range of ozone 

concentrations that were typical in these studies. How relevant are these results to 

the range of ozone standards being considered in this rule?

 Page 93. It is not clear why such behavioral responses are provided as a source of 

under-estimation. These behavioral/averting responses may include costs, such as 

the cost of staying indoors instead of going outside. But in this example the costs of 

staying indoors are presumably lower than the costs of going outside. Therefore, an 

estimate of hospital admissions that did not include behavioral responses would 

actually over-estimate the true cost of higher ozone concentrations. The health costs 

of higher concentrations should account for averting behavior, because such 

averting behavior would actually occur.

 Page 138. As commented on page 93, accounting for averting behavior (for example, 

by controlling for averting behavior in a multivariate regression) would lead to 

larger health effects than failing to do so. But if we believe that individuals will 

actually try to avoid high-ozone concentrations, the actual health effects of higher 

ozone concentrations would be net of such averting behavior. Therefore, accounting 

for averting behavior would yield over-estimates of the health benefits that would

actually occur if ozone concentrations decrease.

 Page 210. Given the uncertainties noted elsewhere about the epidemiological 

evidence, this emphasis makes sense. However, the controlled human exposure 
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studies mostly include young and healthy adults. This section should draw a 

stronger connection between the evidence for young and healthy adults and the 

population groups discussed in the exposure analysis—particularly, children. 

Specifically, if the epidemiological evidence is discounted, what is the remaining 

evidence that children in the real world would experience the same (or worse) 

effects as the young and healthy adults in the controlled exposure studies? 

 Page 212. What is the evidence that this similarity across population groups persists 

at 60, 70, or 80 ppb? Is this evidence more solid that the overall epidemiological 

evidence, about which a variety of uncertainties were noted above? Children could 

be more or less sensitive than other groups at these low concentrations. Suggest 

providing clearer evidence that children are indicative of exposure patterns for 

other groups.

 In the section describing the Administrator’s proposed decision on the primary 

NAAQS, would it benefit the proposal to explain the Administrator’s reasoning more 

explicitly for why a standard in this range would protect sensitive populations 

(given the case law that suggests this should be an important consideration)? Is the 

emphasis in the discussion of the primary standard on asthmatic children sufficient 

to cover all sensitive populations?

Form 

 Page 227. Please explain in more detail how this reflects the continuum of health 

effects associated with increasing ambient concentrations. Under this form, a 

monitoring site could record three very, very high levels of ozone concentration 

each year and remain in attainment.

Monitoring 

 Page 476. Please be more explicit about what changes the EPA might consider. For 

example, would the EPA consider year-round monitoring for all locations? The 

argument for extending further would be a) more accurate determination of ozone 

attainment and b) data that would be useful in determining future standards, which 

could conceivably push below the levels currently being considered.

Prevention of Significant Deterioration (PSD)

 Page 542. Some commenters not that this grandfathering provision is very sensible, 

overall, but it does raise one concern: what is the likelihood that this provision will 

yield to an increase in applications between publication of the proposed rule and 

finalization? Because the question here is specifically about the period between 
Summary of Interagency Working Comments on Draft Language under 

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proposal and finalization, this question is somewhat different from the discussion 

that begins on page 549 about the transition to the new standards.

Different primary and secondary ozone NAAQS and the General Conformity 

determination thresholds.

 If the final primary and secondary ozone NAAQS will be different and if the 

classification threshold methodology that EPA uses for the secondary NAAQS differs 

from that of the primary NAAQS, it is possible that the tables in the General 

Conformity regulations at 40 CFR 93.153(b) will need to be revised, accordingly.

In paragraph VII.A.4 of the draft preamble to the proposed rule for the ozone 

NAAQS, EPA discusses the possibility that the primary and secondary ozone NAAQS 

could end up being different. To account for this possibility, EPA is considering 

methodologies for establishing air-quality based thresholds for assigning the CAA § 

181 classifications to areas that are not in attainment with a secondary ozone 

NAAQS that differs from the primary ozone NAAQS. If the secondary ozone NAAQS 

does end up being different from the primary ozone NAAQS, then not only will EPA 

need to consider a separate classification threshold methodology for the secondary 

ozone NAAQS, but EPA will also need to consider the possibility that the tables in 

the General Conformity regulations at 40 CFR 93.153(b) will need to be revised, 

accordingly, to ensure that the tables continue to be viable. 

If the final primary and secondary ozone NAAQS will be different and if the 

classification threshold methodology that EPA uses for the secondary NAAQS differs 

from that of the primary NAAQS, then EPA will need to ensure it considers whether 

the tables in 40 CFR 93.153 will need to be revised, accordingly.

Secondary Standard

 When outlining the Administrator’s proposed decision on the secondary NAAQS, 

rather than phrasing the proposed level as “within a range identical to the proposed 

range for the primary standard,” why doesn’t EPA instead refer to the numeric 

range (65 to 70)? This may strengthen the agency’s case that the proposed 

secondary standard reflects a careful step-by-step analysis of whether a given 8-

hour level (65-70) can achieve the appropriate seasonal/cumulative average 

outcome and may help avoid the misimpression that EPA is trying to achieve a predetermined outcome of not setting a separate secondary standard.

 EPA requested comments (p. 533) on the unique implementation issues that would 

arise if the EPA were to establish a separate and distinct secondary standard, 

including impacts to conformity demonstrations. On page 558, under “Will 

Transportation and General Conformity Apply to a Distinct Secondary O3 NAAQS, if 
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One is Established?,” the preamble states that “because the CAA refers to the NAAQS 

without distinguishing between them, conformity applies to both the primary and 

secondary NAAQS for all criteria pollutants. Therefore, if a distinct secondary O3 

NAAQS is established, both transportation and general apply in any areas 

designated nonattainment for such a NAAQS.” Some commenters support the 

option of setting the secondary standard to match the primary standard in form and 

in level. A distinct secondary standard using a weighted seasonal average would 

present a new set of transportation conformity challenges for the highway program. 

For example: How would conformity be demonstrated in areas solely designated for 

the secondary standard?

What would be the metric for emissions quantities appropriate to a weighed 

seasonal standard? (Currently, transportation practitioners use tons per (summer) 

day for the parts per million form for ozone.)

What transportation data would be appropriate to generate on-road emissions 

estimates from the transportation sector for a weighted seasonal average? Are these 

transportation data available? Are they accurate?

How would conformity apply once areas designated nonattainment for the 

secondary standard are redesignated attainment (e.g., maintenance areas) because 

areas designated under a secondary standard are not required to complete a CAA 

Section 175A maintenance plan, which is the definition for maintenance areas under 

the Transportation Conformity Rule (40 CFR Part 93).

To meet these new requirements, substantial resources are expected to be needed 

from state/local transportation and air agencies, metropolitan planning 

organizations (staff and board members), and federal agencies to analyze 

conformity with implementation plans for a distinct secondary standard. It is not 

clear if on-road mobile source emissions play a significant role. If environmentally 

protective of vegetation/public welfare, utilizing a secondary standard matching the 

primary standard would considerably lighten the resource load for the on-road 

transportation community for implementing the new NAAQS, and spend the limited 

resources on the primary standard that we know a reduction in mobile source 

emissions can play an important role in protecting human health.

State, local and tribal agency ozone SIP inventories should be maintained on an 

annual basis

 State, local and tribal agencies that use ozone SIP inventories as a method of 

determining conformity of planned federal projects to ozone SIPs need to ensure 

that their inventories are current to facilitate compliance of federal agencies with 

CAA § 176(c).

It has been the experience of some federal agencies that in conducting conformity 

determinations, ozone SIP inventories maintained by state and local agencies are 
Summary of Interagency Working Comments on Draft Language under 

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sometimes not current enough to facilitate making a timely determination that 

planned federal projects conform to an ozone SIP. In such instances, state and local 

agencies must take the time to update their ozone SIP inventories in order to make a 

determination regarding whether planned federal projects conform to an ozone SIP. 

Such delays hinder the ability of federal agencies, to comply with CAA § 176(c) and 

have the potential for delaying planned federal projects and adversely impacting the 

ability of federal agencies to accomplish their mission. 

In the preamble to the proposed rule for the ozone NAAQS, EPA should encourage 

state, local and tribal agencies that use ozone SIP inventories as a method of 

determining conformity of planned federal projects to SIPs to make sure that the 

inventories are current to facilitate compliance of federal agencies with CAA § 

176(c). Section VII.E.5 of the preamble to the proposed rule appears to be an 

appropriate location for EPA to include language to encourage state, local and tribal 

agencies to maintain current ozone SIP inventories. 

Some commenters suggests adding the following language just before the last 

sentence of the first paragraph in section VII.E.5: “However, because some federal 

agencies may not have an established emissions budget in the SIP, state, local and 

tribal agencies are encouraged to maintain ozone SIP emissions inventories on an 

annual basis, at a minimum, to facilitate compliance of federal agencies with CAA § 

176(c).” 

Implementation

 EPA notes (p. 530) its intention to use the same general framework of the 2008 

ozone NAAQS for implementing the revised (2014) ozone NAAQS and proposes to 

issue a SIP Requirements Rule. The 1997 ozone standard was revoked for 

conformity purposes under the Classifications Rule for the 2008 ozone standard as 

opposed to the SIP Requirements Rule mentioned in the NPRM., Some commenters 

support revocation of the 2008 ozone standard for conformity purposes, however 

we prefer the general approach of revoking the previous ozone standard entirely. 

This will avoid transportation and general conformity practitioners completing 

conformity determinations to multiple ozone standards simultaneously. This 

revocation adequately provides air quality protection while reducing the resource 

load of implementing a new standard and providing increased certainty for the onroad transportation community.

How Background 03 is addressed in CAA Implementation Provisions

 In the discussion of relief mechanisms associated with management of background 

03 EPA should consider including a discussion of economic development zones 
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(EDZs) per section 173(a)(1)(B) of the CAA in nonattainment areas as an additional 

vehicle for regulatory relief. 

 EPA should clearly recognize the current effect of wildfires on ozone and consider 

the future trends of wildfire which indicate a growing impact on air quality in the US 

through direct inclusion into all definitions of background used in the rule. 

Additionally current language of the rule does not address the role of prescribed fire 

as a critical fuels management technique which has been previously recognized by 

EPA as able to “reduce the risk of adverse health and environmental impacts due to 

catastrophic wildfire.” EPA should clearly define the natural role of prescribed fire 

in response to the wildfire threat and the importance of this and other fuels 

management tools for long-term vegetation management and health that could 

potentially be limited in subsequent nonattainment areas. 

 EPA should include language which clearly outlines the need to address fuels 

management and protect the use of natural prescribed fire in areas which may 

become nonattainment for either the primary and secondary standard.

 It is highly likely that the growing impact of wildfire may mask indication of 

progress towards improving air quality as has been found in addressing regional 

haze. It is critical that EPA address the role of wildland fire in all three types of 

background cited in the rule. The constructive use of the three types of background 

for this rule with direct consideration of wildland fire can address a number of 

issues and could aid considerably in reducing risk to public and firefighter safety by 

allowing natural fuel build-ups to be addressed. In the Rule EPA should: 1) cite the 

importance of natural prescribed fire for reducing the risk of wildfire; 2) insert the 

importance of addressing fuels management including use of fire within 

nonattainment and transport areas; 3) directly acknowledge the role that firedependent ecological systems play in maintaining the nation’s carbon security; and 

4) insert a process by which natural prescribed fire can be included in the 

appropriate background for ozone. An annual assessment of background including 

wildland fire impacts by EPA could appropriately guide and allow progress towards 

meeting the standard. 

 The influence of Canadian and Mexican wildfires on ozone is also significant and 

needs to be considered as a background component addressed by directly in the 

rule and by EPA. Reliance on the Exceptional Event Rule to track the important 

influence of these wildfires is not feasible by states. The current criteria for ozone 

exceptional events is to consider only when there is an ozone exceedance and not 

just elevated levels which could be critical when addressing the secondary standard 

as well for areas with little margin due to high background ozone levels. It is far 

beyond the scope of single states in terms exceptional events of international 

wildfire’s influence on ozone levels. 
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 Under the CAA amendments of 1977, the Federal Land Managers (FLMs) have the 

responsibility to set air quality related values (AQRVs), including identifying the 

ozone exposure thresholds to protect the vegetation Air Quality Related Values 

(AQRVs) for federally mandated Class I areas. The FLM’s retain the ability to cite 

impacted AQRVs (even when an area complies with the primary and secondary 

standards) in New Source Review, PSD, and other decision-making arenas affecting 

ozone exposures in Class I areas. Some commenters request that this be recognized 

in the new rule. 

 Some commenters are concerned that the 8-hour daily exposure period will be 

inadequate for some Class I areas, where peak ozone levels may occur after 8:00 PM 

due to the regional transport of ozone. In the AQRVs analysis, it may be helpful to 

use values for the entire 24-hour period and take into consideration the frequency 

of acute ozone exposures. 

 It is critical in this rule to have EPA reaffirm that General Conformity can be 

addressed for prescribed fire activity when conducted under a Smoke Management 

Program or using Basic Smoke Management Practices (as defined by USDA, 2011) .

Statutory and Executive Order Reviews

 It is not clear how the Agency has determined that the provisions of UMRA do not 

apply to this rulemaking and while at the same time acknowledging that the action 

is an Economically Significant” action because it is likely to have an annual effect on 

the economy of $100 million or more. It is unclear how these two premises can be 

consistent. Can EPA provide some additional analysis or explanation for why 

sections 202, 203 and 205 of UMRA do not apply to this rulemaking?

 Similarly, it would be helpful if EPA could provide some additional explanation 

regarding the conclusion that this rulemaking will not have Federalism implications. 

Please provide additional analysis specifically regarding the premise that “states 

will have a substantial interest in this rule and any corresponding revisions to 

associated SIP requirements and air quality surveillance requirements” contained in 

the Federalism section of the preamble (pp. 578). 

Other General Comments 

 Discussion in the proposed rule of the Cross State Air Pollution Rule should be 

updated to reflect the fact that on October 23, 2014, the DC Circuit issued the 

attached order lifting the judicial stay of CSAPR.
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 The pin cite to ATA III on p. 33 of the proposed rule should be corrected as follows: 

ATA III, 283 F.3d at 279 379

 On page 2 of the preamble please clarify that EPA is proposing to revise the 8 hour

primary standard.