Summary of Interagency Working Comments on Draft Language under 

EO12866/13563 Interagency Review. Subject to Further Policy Review.

 Table 3-1 – EPA has assumed no change in VOC or NOx emissions from Fires (both Wild and 

Prescribed) and Biogenics in their Base Case modeling between 2011 and 2025. It would 

seem that fire emissions would increase – wildfire is likely to be more prevalent if prescribed 

fire is not allowed or suppressed, and wildfire emissions are much greater than prescribed 

fire emissions due to the fire and emission characteristics of wild vs. prescribed fire. Also, if 

improved ozone concentrations result in improved vegetative health and vigor, it would be 

reasonable to expect that VOC emissions from vegetation will likewise increase. Assuming 

that these two categories will stay the same is just not a good assumption.

EPA Response: EPA recognizes that climate change may lead to temperature 

increases, higher stagnation frequency, and increased wildfire activity, all of which 

could lead to higher ozone concentrations. Potential future elevated ozone 

concentrations could, in turn, necessitate more stringent emissions reductions.

However, there are significant uncertainties regarding the precise location and timing 

of climate change impacts on ambient air quality. Generally, climate projections are 

most robust for periods at least several decades in the future because the forcing 

mechanisms that drive near-term natural variability in climate patterns (e.g., El Nino, 

North American Oscillation) have substantially larger signals over short time spans 

than the driving forces related to long-term climate change. It should be noted that 

international emissions, which may also influence future ozone concentrations, are 

also held constant in this analysis based on a similar rationale regarding the 

significant uncertainty in estimating future levels. We have added the above 

explanation to the RIA. 

In addition, the impacts of ozone levels on biogenic emissions are not currently 

included in biogenic emissions models. Therefore it is not possible at this time to 

project how lower ozone levels might impact biogenic VOC emissions.

 In Appendix 6A, there is additional considerable discussion of crop yield improvements due 

to improved ozone concentrations. However, all of these improvements are based on 

modeled conditions of theoretical research. For soybeans especially, there appears to be no 

good correlation between actual yields (using data from the 2012 Census of Agriculture) for 

nonattainment counties in 5 nonattainment areas in the upper mid-West vs. those 

attainment counties directly adjacent to the nonattainment counties (in Indiana, Illinois, 

Missouri, and Ohio, as well as a few additional counties in Kentucky and Wisconsin to 

complete the nonattainment areas and surrounding attainment counties). In fact, the 

nonattainment counties in those areas in 2012 generally had a higher yield per acre than the 

attainment counties immediately surrounding them. EPA had intended to address some of 

this uncertainty in the preamble document, but it appears that they are still relying on 

benefits from crops in the RIA. The commenters would recommend that this discussion in 

the RIA be quite limited, as it appears that EPA’s modeling isn’t matching reality for

crops. Additionally, EPA states “Crop acreage was projected to decline with the introduction 

of the ozone standards because additional productivity per acre reduces the demand for 

crop acreage...” (see p. 6A-29, section 6A.2.1.2). Given the increasing worldwide population 

and the worldwide demand for agricultural crops, a small increase in production due to 
Summary of Interagency Working Comments on Draft Language under 

EO12866/13563 Interagency Review. Subject to Further Policy Review.

improved ozone concentrations (if that is actually correct) will not result in a decrease in 

agricultural crop acreage anytime in the near future. That decision will be driven more by 

global crop demand, so EPA’s assumption in their modeling is incorrect. As such, the 

commenters strongly recommend scaling back the discussion on benefits from crops, as 

there appear to be incorrect assumptions and inconsistencies with reality in EPA’s current 

modeling assessment.

EPA Response: EPA does not rely on benefits from crops in the RIA; the welfare cobenefits 

are not added to the human health benefits in any presentation of benefits or net benefits 

in the RIA.

In the RIA, EPA used a peer-reviewed model of changes in agricultural and timber markets 

using concentration-response functions from the Integrated Science Assessment for Ozone 

and Related Photochemical Oxidants to assess regional changes in ozone 

concentrations. The analytical approach employed by the commenter is not directly 

comparable to the approach EPA employed. In addition, Appendix 6A is a support 

document for the FASOMGHG modeling conducted to assess welfare cobenefits associated 

with crop and timber production. The scenarios analyzed in the Appendix are illustrative, as 

described elsewhere in the RIA, and the assumptions used in the FASOMGHG modeling are 

detailed in the Appendix. Assumptions are made in any type of modeling and were used in 

this analysis, for example, to assign crop and timber lands to a particular product because it 

is not known how crop and timber producers will allocate their lands in the future under 

actual conditions. Because EPA does not rely on welfare cobenefits in estimating benefits 

associated with the proposed standards, EPA does not plan to change the current discussion 

in Chapter 6 or Appendix 6A of this proposal RIA.

 Page 2-1, please change wildfires to wildland fires in the sentence (wildfires have never 

been considered as anthropogenic under any EPA rule or policy to date): Thus, emissions 

from plants, animals, and wildfires wildland fires 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)

EPA Response: The EPA agrees that this language could be misinterpreted and has removed 

this sentence and the preceding sentence from the RIA. 

 Page2-13, please clarify and specify the fire sources to wildfire, prescribed fire and 

agricultural burning, in the sentence: Fire emissions were based on a multi-year 

climatological average as this analysis was meant to capture seasonal mean background and 

typical ranges rather than explicitly quantify background ozone on specific days.

EPA Response: We have edited the sentence to read: “Wildfire emissions were based on a 

multi-year climatological average as this analysis was meant to capture seasonal mean 

background and typical ranges rather than explicitly quantify background ozone on specific 

days.” Prescribed burns and agricultural fires were treated like other anthropogenic sources 

in that they used 2007 or 2008 year-specific emissions. Therefore these two sources are not 
Summary of Interagency Working Comments on Draft Language under 

EO12866/13563 Interagency Review. Subject to Further Policy Review.

described separately since the previous sentence describes how all anthropogenic sources 

were treated.

 Chapter 3

Page 3-5, please insert in current text (citations are available if needed): ...and more 

prevalent wildfires. In the U.S. over the last 15 years this trend is already occurring with the 

total acres of wildfires increasing and frequency of large wildfires increasing with many 

states recording their largest fires ever. To the extent that climate change does lead to 

higher ozone concentrations, there could potentially be a need for more stringent emissions 

reductions to counteract the higher ozone potential from these phenomena. 

EPA Response: We have added the following sentence to this section: “In the western U.S. 

over the last 15 years, increasing wildfires have already been observed (Dennison et al., 

2014).” 

Additional Changes to RIA

 Chapter 5

A request was made to include the following clarifying edit (shown below as underlined text) in 

Section 5.4.4. Benefit-per-ton Estimates for PM2.5.

Consequently, these estimates may not reflect local variability in factors associated with 

PM2.5-realted health impacts (e.g., population density, baseline health incidence rates) 

since air quality modeling that could have shed light on local conditions was not 

performed for this NPRM.

EPA Response: EPA made the edit, with one exception noted below (shown in underlined text).

Consequently, these estimates may not reflect local variability in factors associated with 

PM2.5-realted health impacts (e.g., population density, baseline health incidence rates) 

since air quality modeling that could have shed light on local conditions was not 

performed for this RIA.

A request was made to include the following clarifying edits (shown below as underlined text and 

strikeout text) in the last paragraph of Section 5.6.3.4. Unquantified Human Health Effects. 

While Graff Zivin and Neidell (2012) report the information needed to quantify ozonerelated worker productivity, we are still evaluating the whether and how to most 

appropriate way to appropriately apply the results of the study in a national benefits 

assessment because this is a nascent literature. Some of the analytic issues to contend 

with include (1) how to assess the robustness the results including whether results can be 

replicated and (2) generalizability of the results to the appropriate population. We are 

considering the feasibility appropriateness of applying the results of this study to estimate 

the benefits of increased worker productivity as part of the final ozone RIA, and seek 

public comment on this approach as an important input to our consideration.

EPA Response: EPA made the majority of the suggested edits, with a few exceptions noted 

below (shown as underlined text and strikeout text).
Summary of Interagency Working Comments on Draft Language under 

EO12866/13563 Interagency Review. Subject to Further Policy Review.

While Graff Zivin and Neidell (2012) report the information needed to quantify ozonerelated worker productivity, we are still evaluating the whether and how to most 

appropriately apply the limited evidence from this results of the study in a national 

benefits assessment because this is a nascent literature. Some of the analytic issues to 

contend with include (1) how to assess the robustness the results including whether 

results can be replicated and (2) An important issue is the generalizability of the results to 

the appropriate population. We are considering the appropriateness of applying the 

results of this study to estimate the benefits of increased worker productivity as part of 

the final ozone RIA, and seek public comment on this approach as an important input to 

our consideration.

 Chapter 7

A request was made to add the following sentence to the last paragraph of Section 7.1.2 

Compliance Cost Estimates for Known Controls.

The reason for slight increase in cost relative to the increase in stringency is newly 

affected areas are expected to comply with known technologies rather unknown 

technologies.

EPA Response: The suggested edit was somewhat out of context, so EPA made the 

following changes to that paragraph (shown below as underlined text and strikeout text). 

The reason for these changes is to (i) remove the reference to Tables 7-1 through 7-3 

because those tables are for total costs, not cost per ton, (ii) clarify that the discussion is 

about cost per ton, and (iii) correct an error in the final sentence in the paragraph.

As shown in Tables 7-1 through 7-3 below, tThe cost trend in terms of dollars per ton of 

emissions reduction 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. The reason for slight increase in cost per ton relative to the 

increase in stringency is that newly affected areas are estimated to obtain emissions 

reductions using slightly more expensive known technologies as the alternative standards 

become more stringent.

A request was made to add the following sentence to the third to last paragraph of sub-Section 

7.3.1. Methods (of Section 7.3 Compliance Cost Estimates for Known Controls).

On the other hand, Figure 1 suggests that $15,000 may be an under-estimate of the 

average value of the unidentified abatement.

EPA Response: The suggested edit was somewhat out of context, so EPA added the following 

sentence in the middle of that paragraph (shown below as underlined text).
Summary of Interagency Working Comments on Draft Language under 

EO12866/13563 Interagency Review. Subject to Further Policy Review.

If, for example, the true costs of the unidentified controls are distributed at the upper end of 

the identified control costs depicted in Figure 7-1, $15,000 per ton may under-estimate the 

average value of the unidentified abatement. Alternatively, the assumed value might 

overestimate the ‘”unobserved” abatement discussed in Section 7.2. The results shown in 

Table 7-4 (per ton cost of NOx reductions for five major NOx-reducing rules) and Table 7-7 

(annualized per ton cost of NOs offsets in four regions) may suggest that the $15,000 per ton 

assumed average cost may be over-estimating the average value of the unidentified 

abatement. 

 Chapter 10

A request was made to delete a sentence above Table 10-1 and delete rows in Tables 10-1 and 10-

2, all related to additional labor categories potentially involved in construction and maintenance 

of control equipment.

EPA Response: The suggested edits to the text and tables were made.