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I. EPA Responses to Specific Interagency Comments, as itemized below

Comments on the Health Effects Information

1. Comment: 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.

EPA response: We have added clarifying text that refers to the sections of the 

proposal where the ambient O3 concentrations in locations of epidemiologic studies 

are discussed (i.e., sections II.D.1.b and II.E.4.a).

2. Comment: 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.

EPA response: We have provided interagency reviewers with the requested 

studies. In addition, on page 63 we have added clarifying text that refers readers to 

the sections of the proposal where we discuss the approach to using results from 

controlled human exposure studies conducted in healthy adults to provide 

perspective on the potential public health impacts of O3-related respiratory health 

effects (i.e., sections II.A, II.C.2, and II.C.3).

3. Comment: 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?

EPA response: We have added clarifying text referring to the sections of the 

proposal where the ambient O3 concentrations in locations of epidemiologic studies 

are discussed (i.e., sections II.D.1.b and II.E.4.a). 

4. Comment: 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, 
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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.

EPA response: The purpose of this paragraph is to note the conclusions of the ISA 

regarding the potential impact of averting behavior on reported health effect 

associations. We have edited the text in this section to clarify its intent. The new text 

more clearly notes the ISA conclusion that epidemiologic studies could 

underestimate the magnitude of health effect associations to the extent members of 

study populations modify their behavior in response to air quality forecasts, and to 

the extent such behavior modification increases exposure misclassification. 

5. Comment: 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.

EPA response: The purpose of this section is to articulate the potential implications 

of averting behavior for the health effect associations reported in epidemiologic 

studies. Similar to our response above, we have modified this language to clarify the 

point that if averting behavior reduces exposure to ambient O3, then epidemiologic 

studies that do not account for averting behavior may produce effect estimates that 

are biased toward the null due to exposure misclassification.

6. Comment: Page 210. Given the uncertainties noted elsewhere about the 

epidemiological evidence, this emphasis makes sense. However, the controlled 

human exposure 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? 

EPA response: We have added text identifying the sections of the proposal where 

we discuss the use of evidence from controlled human exposure studies conducted 

in healthy adults to characterize the potential for adverse effects, including in at-risk 

groups such as children and asthmatics (i.e., II.C.2 and II.C.3.a). We have also 
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inserted text identifying the sections of the proposal where we discuss CASAC 

advice on this issue (i.e., II.D.3 and II.E.4.b).

7. Comment: 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.

EPA response: We have added text to clarify the conclusion that the patterns of 

exposure estimates across urban study areas, across years, and across air quality 

scenarios are similar in adults with asthma, older adults, all children, and children 

with asthma, though smaller percentages of adult populations are estimated to 

experience exposures of concern than children and children with asthma. We have 

also added a reference the section of the proposal notice (i.e., II.C.2.a) where the 

basis for this conclusion in the HREA is discussed in more detail. 

8. Comment: 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?

EPA response: We believe that this section adequately and appropriately 

articulates the Administrator’s reasoning as to why a revised standard with a level 

from 65 to 70 ppb would protect sensitive populations. 

Comments on the Form of the Standard

9. Comment: 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.

EPA response: We have added text to clarify that, with an exceedance-based form, 

days on which the ambient O3 concentration is well above the level of the standard 

are given equal weight to those days on which the O3 concentration is just above the 

standard (i.e., each day is counted as one exceedance), even though the public health 

impact of such days would be very different. In contrast, with a concentration-based 

form, days on which higher O3 concentrations occur would weigh proportionally 
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more than days with lower O3 concentrations since the actual concentrations are 

used directly to calculate whether the standard is met or violated. 

Comments on Monitoring 

10. Comment: 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.

EPA response: EPA’s solicitation of comment is directed toward obtaining 

responses to the specific state-by-state changes proposed in the monitoring section, 

as well as the proposed year-round ozone season for NCore multipollutant sites. 

Based on the levels of the NAAQS being considered in the proposal as well as the 

analysis of ambient data between 2010-2013, we believe the proposed changes 

appropriately balance the objective of having the ozone monitors operating when 

levels are likely to approach the NAAQS with the burden to the states of having to 

operate monitors for longer periods of time. We have proposed year-round seasons 

where the data indicate such a need exists (e.g., Florida, Colorado, and Utah). In our 

judgement, the value of requiring year-round operation for all monitors in other 

states is not warranted given the relatively low ambient levels that would be 

measured. We do note the proposed year-round operation of the NCore ozone 

monitors which would provide 1 or 2 year-round monitors in every state to support 

many objectives including the investigation of ozone patterns during periods when 

photochemistry is perhaps less well understood or characterized.

Comments on Prevention of Significant Deterioration (PSD)

11. Comment: 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 proposal and finalization, this question is somewhat different from 

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

EPA response: EPA does not believe that there will be a rush of applications 

between the proposal and final rule. Most PSD projects take a relatively long time to 

plan and permit applications include several different analyses that also take time to 

prepare. So while there may be some applicants that may be able to accelerate their 
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applications or the application process to make use of the grandfathering provision, 

it seems unlikely that many would be in a position to do so.

Comments on the Different Primary and Secondary Ozone NAAQS and the General 

Conformity Determination Thresholds

12. Comment: 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.

EPA response: In the event that EPA finalizes a distinct secondary ozone NAAQS, 

we would address the details of implementing such a NAAQS in rulemaking and/or 

guidance that would be issued at a later date. The EPA would consider and address, 

as appropriate, impacts of a distinct secondary standard on the tables located in 40 

CFR 93.153. No edits to proposal needed. 

Comments on the Secondary Standard

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

EPA response: On pages 2, 449, and 451 (page numbers based on Interagency 

review draft), we have made the suggested edits to the text describing the proposed 

revisions to the secondary standard. 

14. Comment: 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 

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?

EPA response: In the event that EPA finalizes a distinct secondary ozone NAAQS, 

we would address the details of implementing such a NAAQS in rulemaking and/or 

guidance that would be issued at a later date. As was discussed the last time EPA 

considered revising the ozone NAAQS and possibly setting a distinct secondary 

NAAQS, we continue to believe that the transportation conformity rule is structured 

so that it would apply to a distinct secondary NAAQS. No edits to proposal needed.

15. Comment: 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.)

EPA response: In the event that EPA finalizes a distinct secondary ozone NAAQS, 

we would address the details of implementing such a NAAQS in rulemaking and/or 

guidance that would be issued at a later date. No edits to proposal needed.

16. Comment: 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?
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EPA response: In the event that EPA finalizes a distinct secondary ozone NAAQS, 

we would address the details of implementing such a NAAQS in rulemaking and/or 

guidance that would be issued at a later date. No edits to proposal needed.

17. Comment: 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).

EPA response: We believe US DOT is aware that transportation conformity applies 

in maintenance areas only if they are redesignated to attainment with an approved 

CAA section 175A maintenance plan. Since CAA section 175A maintenance plans 

are not required in order for areas to be redesignated for a secondary NAAQS, 

transportation conformity ceases to apply in such areas on the effective date of their 

redesignation. No edits to proposal needed.

18. Comment: 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.

EPA response: We thank the interagency commenters for this input. No edits to 

proposal needed.

Comments on State, local and tribal agency ozone SIP inventories 

19. Comment: 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 

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 
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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).” 

EPA response: It is the responsibility of the states with areas designated as 

nonattainment to develop inventories. States with nonattainment areas classified as 

Moderate and higher are required to develop implementation plans that detail the 

controls to be implemented to bring the area into attainment by the specified 

attainment date. Such plans contain motor vehicle emissions budgets (MVEBs). 

These MVEBs should reflect all anticipated roadway projects in the nonattainment 

area. Regarding the suggested language for general conformity, the EPA agrees that 

the suggested text would provide additional clarity. The EPA agrees to put a slightly 

modified version of the sentence in the location specified by the commenter.

Comments on Implementation

20. Comment: 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 
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reducing the resource load of implementing a new standard and providing 

increased certainty for the on-road transportation community.

EPA response: Thank you for your input. As indicated on page 526 of the proposal, 

the EPA intends to propose an implementation rule for the 2015 ozone NAAQS 

within 1 year of finalizing the NAAQS and to finalize an implementation rule within 

2 years of finalizing the NAAQS. We would consider revocation of the 2008 NAAQS 

at that time. No edits to the proposal needed.

Comments on how Background 03 is Addressed in CAA Implementation Provisions

21. Comment: In the discussion of relief mechanisms associated with management of 

background 03 EPA should consider including a discussion of economic 

development zones (EDZs) per section 173(a)(1)(B) of the CAA in nonattainment 

areas as an additional vehicle for regulatory relief. 

EPA response: It is unclear what background-related ozone relief is being 

suggested through this statutory provision. The provision allows states to provide 

relief for major sources (locating in nonattainment areas designated as Economic 

Development Zones (EDZ)) from obtaining “offsets.” States can establish an EDZ, 

subject to EPA approval, upon a satisfactory showing that meets certain criteria 

including that emissions of such pollutant resulting from proposed new or modified 

stationary sources in that area will not cause or contribute to emissions levels that 

exceed the allowance permitted for such pollutant for such area from new or 

modified major stationary sources. However this provision does not seem relevant 

to "background" ozone. No edits to proposal needed.

22. Comment: 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 response: Fire-related issues are addressed separately in response to firerelated communication provided to EPA on 11/12/12014. The EPA has also added 

language in VII. F.1. noting that temperature increases could lead to more prevalent 

wildfires, the impacts of which may be lessened by various mitigation measures. 
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23. Comment: 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.

EPA response: Fire-related issues are addressed separately in response to firerelated communication provided to EPA on 11/12/12014. The EPA has added 

language in VII. F.1. noting that temperature increases could lead to more prevalent 

wildfires, the impacts of which may be lessened by various mitigation measures. 

24. Comment: 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 

fire-dependent 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. 

EPA response: Fire-related issues are addressed separately in response to firerelated communication provided to EPA on 11/12/12014. The EPA has added 

language in section VII. F.1. to clarify that background O3 generally refers to O3 that 

originates from natural sources of O3 (e.g., wildfires and stratospheric O3 

intrusions) and O3 precursors, as well as from manmade international emissions of 

O3 precursors. The EPA has also added language in VII. F.1. noting that temperature 

increases could lead to more prevalent wildfires, the impacts of which may be 

lessened by various mitigation measures. Identifying and implementing appropriate 

mechanism(s) to mitigate the effects of wildfires is a state decision that is part of the 

State Implementation Plan process. The EPA does not intend to endorse one 

mitigation approach over another. Committing resources to assess the impacts of 

potential future fires requires a policy decision that is outside the scope of this O3 

NAAQS process. 

25. Comment: 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 
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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. 

EPA response: Fire-related issues are addressed separately in response to firerelated communication provided to EPA on 11/12/12014. The EPA has also added 

language in section VII. F.1. to clarify that background O3 generally refers to O3 that 

originates from natural sources of O3 (e.g., wildfires and stratospheric O3 

intrusions) and O3 precursors, as well as from manmade international emissions of 

O3 precursors. Canadian and Mexican wildfires would be included in the definition 

of natural background and could be excluded from use in regulatory decisions by 

employing the provisions in the Exceptional Events Rule. The EPA is currently 

undertaking a notice-and-comment rulemaking effort to revise the Exceptional 

Events Rule and develop wildfire/ozone implementation guidance, both of which 

are intended to streamline the exceptional events demonstration development 

process. 

26. Comment: 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. 

EPA response: It is unclear what the commenter is asking for here. Further, the 

FLM has its role clearly defined in §165(D) and this provision is not addressed in 

this rulemaking. We believe that clarification of the statutory and historical 

participation of the FLM has already been established and is outside the scope of 

this rulemaking.

27. Comment: 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. 

EPA response: It is unclear what the commenter is addressing here. Nonetheless, 

the commenter’s suggestion is beyond the scope of this rule. It is the FLMs that 
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protect the AQRVs and make judgments about the information needed for such 

protection. 

28. Comment: 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).

EPA response: General Conformity applies in nonattainment areas. It is unclear to 

the EPA why this is a critical issue for this rulemaking, which does not address 

nonattainment area-related requirements. Nonattainment areas for a revised 

NAAQS would not be established until 2017. The General Conformity regulations, 

which were last revised April 15, 2010 (75 FR 17254) provide flexibilities in 40 CFR 

93.153 (h) and (i) for prescribed fires to meet general conformity requirements 

using SMPs and BSMP. No edits to proposal needed. 

Comments on the Statutory and Executive Order Reviews

29. Comment: 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?

EPA response: We are in the process of updating the EO section to be consistent

with the most recent templates. 

30. Comment: 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). 

EPA response: We are in the process of updating the EO section to be consistent

with the most recent templates. 

General Comments 
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31. Comment: 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.

EPA response: We have made this change. 

32. Comment: 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

EPA response: We have made this change.

33. Comment: On page 2 of the preamble please clarify that EPA is proposing to revise 

the 8 hour primary standard. 

EPA response: We have made this change.

II. Additional Changes Made in Response to Interagency Comments 

1. Primary standard

In section II.E.4.d, we have added clarifying text on margin of safety considerations 

and on CASAC’s advice with respect to margin of safety. 

In section II.C.3.a.ii, we have added additional text identifying asthma severity and 

medication use as potential sources of uncertainty in using results from healthy 

subjects to estimate risks in asthmatics. 

In section II.E.4.d, we have provided additional explanation for the relative impacts 

of standard levels of 65 and 70 ppb on estimates of premature mortality. 

In the discussion of standard levels below 65 ppb in section II.E.4.d, we now refer to 

“moderate or larger” lung function decrements rather than “moderate to large” 

decrements. 

We have made additional editorial changes throughout the draft notice, based on 

the track changes document sent from OMB to EPA. 

2. Secondary standard

In section IV.E, we are adding further clarification of the framework in the NPR (and 

legal necessity of this framework) which focuses on identifying an appropriate level 

of protection and considering the protection afforded by potential alternate levels of 
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protection (in the form of the W126 metric) before discussing the Administrator’s 

consideration of whether the current averaging time and form also provide 

protection to vegetation when set at an appropriate level.

In various locations in section IV, we are removing redundancies in discussion of the 

impacts of ozone on crops and the importance to public welfare of these effects.

We have made additional editorial changes throughout the draft notice, based on 

the track changes document sent from OMB to EPA. 

3. Implementation-related sections

In several locations, we are updating the text to reflect the lifting of the stay of the 

Cross-State Air Pollution Rule.

In section VII.F.3, we are adding text to clarify that states can use the 2005 

overwhelming transport guidance for the purpose of developing technical 

information to support a request that the EPA treat a specific nonattainment area as 

a rural transport area.