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 Some commenters would like to better understand the implied consequences for small 

businesses that arise from the mix of known and unknown control strategies. To the extent that 

EPA projects costs based on known control strategies already considered in other rulemakings, 

we request EPA provide discussion of the relative contribution of small entities to the emissions 

inventory and the extent to which EPA has implicit assumed in its economic analysis that small 

entities would install control equipment not otherwise required in industry specific rules.

EPA Response: The control strategies presented in the RIA are not based on known control 

strategies from other rulemakings. The control strategy analysis in the RIA relies on emissions 

and engineering data from the National Emissions Inventory (NEI), which does not include 

comprehensive NAICS information, and therefore does not contain information on entity size. 

See additional discussion below (in response to next comment) related to lack of information on

entity size.

 Some commenters have attempted to understand these impacts for ICI boilers, but could not 

recreate the impacts based on the information made available so far. It is not clear in the RIA’s 

estimation of costs and emission reductions from known control strategies applied to ICI boilers 

if these are calculated from major or area sources or both. In order to properly evaluate the 

impact known controls will have on small entities, it is important to understand which sectors 

will have known control costs from ICI boilers at major or area sources. Specifically, to reduce 

emissions further, is EPA assuming that ICI boilers at area sources will now require SCR and LNB 

controls? If major and area ICI boilers apply controls beyond standards in the Boiler MACT, a 

significant percentage of small entities may be impacted. From EPA’s 2013 ICI boiler MACT rule 

at major and area sources, the categories of small entities potentially affected included major 

sources at lumber mills (NAICS 321) and municipal boilers (NAICS 221), and area sources at 

schools (NAICS 611), churches (NAICS 8131), and hospitals (NAICS 622). To determine the 

impact on these entities, we need to find out their appropriate share of the calculated control 

costs. Additionally, we do not have a clear understanding on how the projected costs from NOx 

measures applied to ICI boilers were calculated. When attempting to reproduce the projected 

costs of NOx measures to ICI boilers, we did not reach the same numbers from Ch.7 of the RIA 

when using a straight forward calculation of multiplying the tons reduced per year to the 

average cost per ton for the non-EGU point sector. We suggest EPA further explain how EPA 

arrived at these numbers when determining the costs of NOx measures to ICI boilers.

EPA Response: The estimates of cost and emissions reductions from known control strategies 

applied to ICI boilers include major and area sources. 

EPA is not expressly requiring ICI boilers at area sources to install SCR and LNB controls -- the 

RIA reflects illustrative control strategies of possible approaches to attain potential alternative 

standards in 2025 of 70 ppb and 65 ppb, as well as one more stringent standard than proposed (60 

ppb). State, local, and tribal agencies will analyze how best to achieve needed emissions 

reductions and will prepare control strategies through their state or tribal implementation plan 

(SIP/TIP) after a standard becomes final. The SIP/TIP process would likely take place several 

years from now and would involve the state/local/tribal agencies gathering current local 

information on sources of emissions, as well as information on control options, impacts of 

controls, and related costs. The SIP/TIP process involves proposing state/local/tribal rules, public 
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hearings, and promulgating state/local/tribal final rules; the final state/local/tribal rules would 

include any requirements for specific sources, including ICI boilers.

The analysis in the RIA relies on emissions and engineering data from the NEI, which does not 

include comprehensive NAICS information, and therefore does not contain information on entity

size. The NEI includes NAICS industry codes for non-EGU point sources, but not for area 

(nonpoint) sources. To the extent that major and/or areas sources are small entities, EPA does not 

have data to establish the connection between emissions source size (major and/or area) and 

entity size (small entity).

EPA can provide more details in the relevant RIA chapters or appendices on how costs were 

estimated for NOx control measures for ICI boilers.

 Similar issues arise in working to understand the incidence of nonroad controls. An unfunded 

nonroad diesel retrofit program would likely impose significant burdens on small entities. Some 

commenters would like to have a better understanding of how much nonroad diesel equipment 

would need to be retrofitted and the economic sectors in which this equipment is operated. In 

sectors for which small entities are a significant presence, EPA may be underestimating the 

average cost of compliance.

EPA Response: EPA is not expressly requiring nonroad diesel retrofits on specific sources -- the 

RIA reflects illustrative control strategies of possible approaches to attain potential alternative 

standards in 2025. In addition, the percent of NOx emissions reductions estimated from nonroad 

diesel retrofits for attainment of a potential alternative standard of 65 ppb is 1% of the total NOx 

emissions reductions, representing a small portion of the illustrative control strategy.

 Some commenters also have significant concerns about the extrapolation of costs for unknown 

compliance technologies, and seeks to better understand how EPA modeled these costs. As 

above, presentation of average costs can hide significant disparities in compliance costs for 

small entities, and where small businesses are a significant proportion of the industry, this may 

lead to underestimates.

EPA Response: EPA understands that costs can vary significantly across emissions source sizes. 

EPA does not have information in the NEI or in the control cost equations, nor other factors 

sufficient to determine the costs for each specific emissions source. As such, EPA presents costs 

averaged across broad sectors of the economy and across broad geographic regions. It is beyond 

the scope of the RIA to reflect specific, detailed costs for each source.

 EPA bases its estimates of the extrapolated costs for emissions reductions to be $15,000 per ton 

using the average-cost methodology. This estimate is based off of known control costs 

available, which does not have a citation, rather than a survey of known control methods most 

likely to be used by firms. Additionally, it is reasonable to expect that the control cost for small 

businesses will be higher than the assumed $15,000 per ton, but the commenters do not have 

the information necessary to understand the extent of this problem because EPA does not 

present industry analysis by subcategories of industry and firm size. Using the average-cost 

methodology combined with economies of scale, costs to small businesses will consistently be 

higher across all small firms.
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 EPA states that their estimate undervalues the higher cost controls that regions may apply to 

meet the alternative standards. This means that small firms may experience an even more 

severe cost of compliance than EPA has accounted for depending on their geographic 

location. This is not factored into the $15,000/ton estimate.

EPA Response: The analysis in the RIA relies on emissions and engineering data from the NEI, 

which does not include comprehensive NAICS, and therefore does not contain information on 

entity size. To the extent that major and/or areas sources are small entities, EPA does not have 

data to establish the connection between emissions source size (major and/or area) and entity size 

(small entity). EPA removed smaller point sources (sources emitting less than 25 tpy) and 

nonpoint (area) source categories for which countywide emissions were below 25 tpy from the 

illustrative control strategies. To the extent that smaller emissions sources are small entities, this 

reduces their inclusion in the illustrative control strategy.

 Interagency commenters request that EPA provide citations for its data sources and discuss in 

greater detail the barriers to obtaining consistent data across original data sources. Without the 

proper citation of sources, it is difficult to replicate and verify EPA’s cost estimates or 

understand the original studies’ methodologies. The commenters wish to encourage EPA to 

share its data sources and methodology in a more transparent fashion.

EPA Response: EPA will post an updated CoST Equation Document and other supporting 

information on the CoST website and will provide more detail in the RIA docket.

 Tables ES-6, ES-8, 5-1, 5-2, 5-23, 5-30, 5C-10 – These tables should be split to show explicitly the 

benefits derived for ozone only and then for total benefits. We agree that the total benefits 

(ozone plus PM) should be shown; however, it is quite informative, especially in an ozone rule, 

to show the ozone-only benefits in addition to the total benefits. That would give the public a 

more complete view of the related benefits achieved by this rule. Additionally, it is unclear 

whether Tables 5-19, 5-20, 5-21, 5-22, 5-26, 5-27, 5C-6, and 5C-7 show combined ozone and PM 

values. If so, these should also be split as suggested.

EPA Response: EPA added ozone-only and PM2.5-only benefits rows to Tables 5-1, 5-2, 5-23, 5-

30 and 5C-10. In the Executive Summary in Tables ES-6 and ES-8 (renumbered to ES-10), EPA 

presents total costs, total benefits and net benefits and references Tables 5-1, 5-2, 5-23, and 5-30 

for additional detail on the benefits breakdown. EPA also modified titles for Tables 5-19, 5-20, 

5-21, 5-22, 5-26, 5-27, 5C-6, and 5C-7 to clearly identify whether they present estimates for 

ozone-only, PM2.5-only, or both combined.

 Tables ES-7 and ES-9 and Section 1.4 – EPA’s analysis of benefits related to human health are 

heavily weighted toward experimental, theoretical, and statistical analyses. EPA has revised the 

O3 NAAQS a number of times since 1979, and there have been many areas that have achieved 

attainment and/or made progress toward achieving previous NAAQS. It would seem reasonable 

that EPA should incorporate information related to the air quality improvement and resulting 

improvement in public health to verify that the assumptions and procedures used in setting the 

NAAQS actually make sense and accurately predict the actual improvement. For example, EPA 
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could look at a number of nonattainment areas for O3 that have achieved the standard and 

answer the following: “We expected __ improvement in O3 concentrations due to the 

implementation and attainment of a certain NAAQS level in area __ and thus we expected to 

achieve __ improvement in public health (choose various public health metrics used in setting 

the standards, such as expected reduced mortalities, expected reduced hospital visits, 

etc.). After implementing the regulations and achieving O3 concentrations of __, we actually 

saw __ improvement in public health.” Conducting such an analysis would lend credibility and a 

valuable means of verifying initial assumptions, as well as verifying those data obtained from 

chamber studies and other experimental work matched reality. As such, EPA should prioritize 

research and analytical efforts to begin evaluating the actual impacts achieved from ozone 

reductions.

EPA Response: This would represent new research conducted in the future and as such is out of 

scope for the current review.

 Chapter 5 (and other benefits analyses) – In estimating costs associated with this rule, EPA 

seems to exclude those costs associated with the implementation of already promulgated or 

known rules. While this is acceptable, EPA needs to ensure that the benefits associated with 

those rules particularly are also excluded such that they are not double-counted. It appears that 

EPA’s ozone benefits estimates simply look at benefits accrued by achieving certain ambient 

standards without instead focusing on the difference in ozone concentrations expected after 

implementation of the promulgated or known rules and achievement of the various standard 

levels included in the analysis. For example, if already promulgated or known rules would result 

in achievement of a 70 ppb level in a certain area, there should be a zero value for benefits 

resulting from this rule in that area, just as there is a zero value for costs to achieve the 70 ppb 

level in that area. In short, benefits (and costs, for that matter) attributed to this rule should be 

strictly limited to those achieved via the attainment strategies needed to achieve the various 

standard levels in addition to those rules already promulgated or known.

EPA Response: All of the alternative standard levels are evaluated for benefits incremental to the 

baseline. As discussed in section 5.2 of Chapter 5, the baseline reflects application of existing 

regulations potentially impacting ambient ozone levels. Consequently, if an existing regulation 

would drive ambient ozone levels in a given location below the current standard, that will be 

reflected in the baseline used to generate benefits estimates for this review. 

 More Specific Comments:

(2-1) In practice, the distinction between natural and anthropogenic sources is often unclear, as human 

activities may directly or indirectly affect emissions from what would have been considered natural 

sources during the preindustrial era. Thus, emissions from plants, animals, and wildfires could be 

considered either natural or anthropogenic, depending on whether emissions result from agricultural 

practices, forest management practices, lightning strikes, or other types of events (US EPA, 2013, 

sections 3.2 and 3.7.1). Modern anthropogenic efforts to restore natural ecological function, such as 

those associated with prescribed fire (both forestry and agricultural) and forest management practices, 

should not be considered anthropogenic. Rather, they are intended to reverse negative anthropogenic 

influences on natural ecosystems.
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(2-16) – General Comment:

The RIA states “Background ozone is a relatively larger percentage (e.g., 70-80%) of the total 

seasonal mean ozone in locations within the intermountain western U.S. and along the U.S. 

border. In locations where ozone levels are generally higher, like California and the eastern U.S., 

the seasonal mean background fractions are relatively smaller (e.g., 40-60%). The additional 

2007 modeling confirms that background ozone, while generally not approaching levels of the 

ozone standard, can comprise a considerable fraction of total seasonal mean ozone across the 

U.S (EPA, 2014c).”

Yet just 2 pages before (p. 2-14) EPA states “From a seasonal mean perspective, background 

ozone levels are typically well-below the NAAQS thresholds.” Clearly, 40-80% background (of 

total) is NOT “well-below.” It is very significant, especially in the rural West, and the statement 

on p. 2-14 can be very misleading and is in fact erroneous. Please provide a more in-depth and 

accurate discussion of background levels in different parts of the country.

EPA Response: EPA has revised the characterization of background ozone from “well-below” to 

simply “below”. EPA has not added any additional information on background ozone to this 

chapter of the RIA, as we believe the in-depth discussion in Chapter 2.4 of the Policy Assessment 

in combination with section 2.4 of this document is already sufficiently detailed.

(2-17) – General Comment:

The RIA states “It should be noted here that EPA has policies for treatment of air quality 

monitoring data affected by these types of events. EPA’s exceptional events policy allows 

exclusion of certain air quality monitoring data from regulatory determinations if a State 

adequately demonstrates that an exceptional event has caused the exceedance or violation of a 

NAAQS. In addition, Section 179B of the Clean Air Act (CAA) also provides for treatment of air 

quality data from international transport when an exceedance or violation of a NAAQS would 

not have occurred but for the emissions emanating from outside of the United States. Finally, 

CAA section 182(h) authorizes the EPA Administrator to determine that an area designated 

nonattainment can be treated as a “rural transport area”. In accordance with the statute, a 

nonattainment area may qualify for this distinction if it meets the following criteria: 1) the area 

does not contain emissions sources that make a significant contribution to monitored ozone 

concentrations in the area, or in other areas; and 2) the area does not include and is not 

adjacent to an MSA.”

First, as some interagency commenters have previously stated regarding the proposed new 

primary and secondary NAAQS levels, EER demonstrations can be unnecessarily burdensome for 

states, and until fire—both wild and prescribed—is fully incorporated into EPA background 

levels there will be an increasing EER burden on the states. EER demonstrations are not easy, 

nor quick. The approach outlined by EPA is not a solution to this major issue.

Second, it would be good to know about “rural transport areas” and how vast areas of the 

western and central US might be designated in this way (esp. w.r.t. fire needs). Please provide 
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more discussion of RTA’s, how they have been used in the past, and the extent to which RTA’s 

can affect the obligations of States to demonstrate attainment in SIPs.

EPA Response: EPA has added an additional sentence to the RIA noting that more detail on how 

background ozone is addressed in CAA implementation is provided in Section VII.F of the NPR. 

A more in depth discussion regarding exceptional event determinations and rural transport areas 

is outside of the scope of the RIA. 

Additional Changes to RIA

 A request was made for EPA to solicit comment on the $15,000/ton costing method for unknown 

controls.

EPA Response: Additional language was added to Chapter 7 to request comment on this topic.

 A request was made for EPA to provide details on what comprises the social vulnerability index 

discussed in Appendix 9A.

EPA Response: EPA removed the term social vulnerability index, and in Section 9A.1.1 of 

Appendix 9A retained separate paragraphs that discuss demographic variables of interest that are 

included in the analysis. Each paragraph contains a reference or references underlying each 

variable (endnotes 3 through 17). 

 A request was made to add language to Chapter 7 about why average costs may decrease when 

analyzing lower alternative standards. 

EPA Response: The following language was added to Section 7.1.2: The cost trend is increasing 

for some sectors and decreasing for others. The variation is small for most sectors and depends on 

the sources that happen to be in the geographic areas of control. In general, the same set of 

controls is being applied at each level of the alternative standards analyzed. The primary 

difference in the control strategies for the alternative standards is the greater size of the 

geographic area of control as the stringency of the alternative standards increases. Overall for all 

sectors as a whole, the average cost per ton is actually increasing slightly with increasing 

stringency of the alternative standard analyzed.

 A request was made to add language in Chapter 7 to the discussion about differences in 

methodology between 2008/10 analyses and the current analysis related to not including in the 

current analysis the hybrid methodology to estimate costs associated with unknown controls. 

EPA Response: In Chapter 7, Section 7.5, EPA added additional language about the hybrid 

approach not being used in this RIA.

 Chapter 9

Table 9-1: Please provide a footnote clarifying what “other or multiracial” constitutes.

Table 9-2: Please provide a footnote clarifying what “low income” constitutes.

EPA Response: Appendix 9A clarifies on page 2 that “other or multiracial” is derived from 

individual reporting on Census forms (Census information referenced in endnotes 1 and 4), and 
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on page 4 that “low income” in this analysis is defined as income two times the poverty line or 

less. EPA has added two footnotes to Tables 9-1 and 9-2 in Chapter 9 to this effect.

 Executive Summary

Suggest deleting “supplemental” in characterizing CA analysis. 

EPA Response: EPA has changed 'supplemental' to 'separate' when referring to the California 

analysis.

 Chapter 5 

Would you clarify exactly what air quality modeling was done to assess the reduction in 

secondary PM formation?

EPA Response: EPA enhanced the discussion to more clearly state that (i) denovo modeling was 

used to generate ozone-specific benefits estimates, and (ii) PM2.5 cobenefits were generated using 

benefit-per-ton values derived using air quality modeling completed prior to this review, i.e., no 

new air quality modeling was completed to estimate the benefit-per-ton values.

5-53 – 5-54: We suggest that using Graff Zivin and Neidell (2012) to assess worker productivity 

may not be appropriate without understanding the generalizability of the study results. We 

suggest that EPA use the previous discussion regarding the nascent literature on the effect of 

ozone on worker productivity.

EPA Response: The text that has been added addresses the issue related to generalizability of 

data from this single study in the context of making national-scale benefits estimates.