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- Environmental Protection Agency (EPA) : Proposed Rule

Fine Particulate Matter (PM 2.5 ) National Ambient Air Quality Standards (NAAQS) :

State Implementation Plan (SIP) Requirements

RIN 2060

- A Q48

Note: This second set of responses to interagency comments responds to follow

- up comments on only selected issues that we addressed in the first set of responses. These follow

- up comments

were received and discussed in conference calls during the week of February 2

- 6, 2015 . Also, the last section addresses five ne w comments that were received on 2/10/2015

.

1. Wildfire and wildland fire

.

a. Initial Comment : Commenter s recommend including additional context and background in the preamble and rule language about prescribed fire (planned ignitions) and wildfire (unplanned ignitions). Specifically, that not including prescribed fire and wildfire may unintentionally set a precedence that limits the options for managing wildland fire, limits the role of wildland fire in restoring and maintaining resilient landscapes, preclude options for effective management of carbon, and inadvertently violate the direction set forth in Exe cutive Order (EO)

13653.

Initial EPA Response : We understand the commenter’s interest in providing more

context for fire related issues . The text below was adapted from language to be

included in the final 2008 ozone SIP requirements rule, and we recommen d adding it as a footnote on page 1 6 , following table 1, which describes national emissions by sector.

“ It should be noted that the “miscellaneous” sector has the highest level of estimated PM2.5 emissions primarily d ue to emissions from wildfire. Wildfir e emissions can significantly contribute to periodic high PM 2.5 levels. Besides their effect on air quality, wildfires pose a direct threat to public safety

– a threat that can be mitigated through management of wildland vegetation. Attempts to suppress wi ldfires have resulted in unintended consequences, including increased risks to both humans and ecosystems. The use of wildland prescribed fire can influence the occurrence of catastrophic wildfires which may help manage the contribution of wildfires to PM 2 .5 concentrations. Additionally prescribed fires can have benefits to those plant and animal species that depend upon natural fires for propagation, habitat restoration, and reproduction, as well as myriad ecosystem functions (e.g., carbon sequestration). The EPA understands the importance of prescribed fire which mimics a natural process necessary to manage and maintain fire

- adapted ecosystems and climate change adaptation, while reducing risk of uncontrolled emissions from catastrophic wildfires,

and is c ommitted to working with federal land managers, tribes, and states to

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- effectively manage wildland fire use to reduce the impact of wildfire related

emissions

. ”

b. New Comment : A reviewer provided the following edits in bold to this paragraph:

“Wildfire e missions are a component of background PM2.5 and can significantly contribute to periodic high PM2.5 levels. Besides their effect on air quality, wildfires pose a direct threat to public safety

– a threat that can be mitigated through management of wildla nd vegetation. Attempts to suppress wildfires have resulted in unintended consequences, including increased risks to both humans and ecosystems. The use of wildland prescribed fire can influence the occurrence, behavior, and effects of catastrophic wildfires which may help manage the contribution of wildfires to background PM2.5 levels and periodic peak PM2.5

events. Additionally prescribed fires can have benefits to those plant and animal species that depend upon natural fires for propagation, habitat restoration, and reproduction, as well as myriad ecosystem functions (e.g., carbon sequestration). The EPA understands the importance of prescribed fire which mimics a natural process necessary to manage and maintain fire

- adapted

ecos ystems and climate change adaptation, while reducing risk of uncontrolled emissions from catastrophic wildfires, and is committed to working with federal land managers, tribes, and states to effectively manage prescribed wildland fire use to reduce the imp act of wildfire related

emissions on PM2.5.

EPA Response : EPA has included the above edits.

New Comment : A reviewer also suggested incl uding the following paragraph to the RACM

section of the rule.

“If wildfire impacts are significant, contributing to exceedances of the standard, states should consider Reasonably Achievable Control Measures (RACM) for this source. Fires play an important ecological role across the globe, benefiting those plant and animal species that depend upon natural fires for prop agation, habitat restoration, and reproduction. Fires are one tool that can be used to reduce fuel load, unnatural understory, and tree density, helping to reduce the risk of catastrophic wildfires. Some wildfires and the use of prescribed fire can influ ence the occurrence of catastrophic wildfires which may reduce the probability of fire

- induced smoke impacts and subsequent health effects. RACM for catastrophic wildfire may include addressing the wildland fuels through fuels management, including the us e of prescribed fire and allowing some wildfire to occur naturally in systems that are ecologically fire dependent. Where appropriate, states, land managers, and landowners may consider developing plans to ensure that

fuel accumulations are addressed and fuels management efforts, including prescribed fire, are not delayed. RACM for prescribed fires should also be considered. Information is available from the DOI and the USDA Forrest Service on smoke management programs and basic smoke management practice s and may be considered when determining RACM for prescribed

fires. RACM must be determined for each area on a case

- by

- case basis.”

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- EPA Response : In a conference call on 2/5/2015, it was agreed that EPA would develop a modified version of this paragraph and would include a request for comment on these issues. Our suggested language to be inserted in the RACM section on page 128 is as follows:

“It was noted in S ection II of this preamble that national PM 2.5 emissions from wildfire

are substantial. In some areas, wildfire impacts can be significant and contribute to exceedances

of the PM 2.5 standard and adverse health effects. Fires also play an important ecological role across the globe, benefiting those plant and animal species that depend upon natural fi res for propagation, habitat restoration, and reproduction. Fires are one tool that can be used to reduce fuel load, unnatural understory, and tree density, helping to reduce the risk of catastrophic

wildfires. Some wildfires and the use of prescribed fi re can influence the occurrence of catastrophic wildfires which may reduce the probability of fire

- induced smoke impacts and subsequent health effects.

In light of these wide

- ranging effects of fire and the uniqueness of this category of emissions, the EPA requests comment on the concept of RACM to reduce the impacts of emissions from catastrophic wildfire and prescribed fire. Wildland fuels can be reduced through fuels management, including the use of prescribed fire and allowing some wildfire to occur

na turally in systems that are ecologically fire dependent. Where appropriate, states, land managers, and landowners may consider developing plans to ensure that fuel accumulations are addressed and fuels management efforts, including prescribed fire, are not delayed. RACM for managing emissions from prescribed fires should also be considered by air agencies. Information is available from the DOI and the USDA Forest Service on smoke management programs and basic smoke management practices. The EPA requests comments and ideas about the concept of RACM for wildfire and prescribed fire, and requests input on practical considerations associated

with how such measures can be characterized in emission s inventor ies and attainment

demonstration s , and made federally enforceable for a doption in a nonattainment area SIP.“

8. Economic feasibility determination

.

Initial Comment : A reviewer has recommended that two additional factors

- 8. Impact on jobs and 9. Cumulative impacts to the source not considered above (e.g., delays in maintenance or other po tential safety

- related actions)

- be added to th e list of economic feasibility factors excerpted from page 142 of the preamble below :

“ In addition, if a state contends that a source

- specific control

- level should not be established because the source(s) cannot afford the control measure or technology that is demonstrated to be economically feasible for other sources in its source category, the EPA proposes that the state must support the claim with information regarding the impact o f imposing the identified control measure or technology on the following financial indicators, to the extent applicable:

1. F ixed and variable production costs ($/unit)

2. P roduct supply and demand elasticity

3. P roduct prices (cost absorption vs. cost pass

- through)

4. E xpected costs incurred by competitors

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- 5. C ompany profits

6. E mployment costs

7. O ther costs ( e.g. , for RACM implemented by public sector entities).

The EPA seeks comment on the factors described above for states to consider when

determin ing whether a control technology or measure is economically feasible. ”

EPA Response : This list of factors is taken from long

- standing guidance (the 1992 General Preamble) that is applicable to implementation of more than just the PM NAAQS. A reviewer has recommended that two additional factors be added to this list: 8. Impact on jobs and 9. Cumulative impacts to the source not considered above (e.g., delays in maintenance or other potential safety

- related actions). We think the guidance has proven suffic iently broad and has provided adequate flexibility to states to be able to present reasoning to demonstrate why certain facilities are not able to afford control technology used on similar sources. C hanging the longstanding guidance risks introducing confu sion to states in their attainment planning process with little potential gain in return.

New Comment : Commenters suggested adding a reference in the text to the relevant guidance mentioned above.

EPA Response : EPA has included a footnote cit ing the 1992 General Preamble appendices in the preamble. The footnote reads:

“ These long

- standing factors were established in EPA guidance in 1992 and are applicable to implementation programs for all NAAQS pollutants. See the appendices to

the General Pr eamble, 57 FR 18070 (April 28, 1992). ”

9. Attainment demonstration.

A. Initial C omment : Reviewer r ecommend s providing a discussion of benefits and costs of each of the proposed alternatives for the attainment demonstration. For example, discuss the rel ative level of risk of just using FRM and/or FEM monitoring data.

Response : On a conference call on 2/2/2015, EPA agreed to add a discussion of the potential

benefits and costs of the four options for unmonitored area analyses. Our suggested insert for

pa ge 182 is below:

“ The four options presented above would lead to a range of potential analy sis costs, control costs, and health benefits. Option 1 would be expected to be the least costly option, in term of both analy sis costs for implementing air agencie s, and in terms of potential control costs for the regulated community. Option 2 would be expected to be the most resource intensive option to implement, and if potential violations were identified in unmonitored areas, this option

could also lead to addit ional costs for regulated entities to reduce emissions. However, any additional emission reductions (in comparison to option 1) that would result from

i mplementation of this approach would lead to additional health benefits in the area. Option 3 is

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- simila r to option 2, except that if a potential violation is indicated in an unmonitored area, there would not be a regulatory requirement for the air agency to identify enforceable controls to eliminate the potential violation. For example, the air agency could instead elect to site a new monitor to further characterize air quality in the area. The analy sis costs associated with option 3 would be the same as for option 2, but the potential for additional control costs and health benefits could vary widely, depen ding on the agency’s assessment and choice regarding further action. Option 4 most closely describes the current policy for the PM2.5 implementation program. Currently, EPA recommends that air agencies conduct an unmonitored area analysis,

but there is no regulatory requirement for the air agency to either perform an unmonitored area analysis or to impose control requirements if the analysis indicates potential violations. Thus, under option 4, if an unmonitored area analysis is performed, the analy sis cost s associated with this option would be the same as for option 2 . S imilar to option 3, the potential for additional control costs and health benefits could vary widely, depending on the agency’s assessment. Under option 4, if it is determined by EPA and the air agency to be unnecessary to perform an unmonitored area analysis, there would be no additional analy sis or control costs or health benefits beyond the monitor

- only approach of option 1. ”

10. Credits for outside of nonattainment area for reasonable further progress (RFP).

a. Comment : Reviewer r ecommend s providing additional discussion why EPA thought it was appropriate to allow up to 200 kilometers (km) away from the nonattainment area for RFP in the

2007 PM 2.5 Implementation Rule and doe s not believe that it is still appropriate.

Response : On 1/23/2015, we indicated we would add clarifying text to page 19 9 to explain

t he issue more clearly and fully, and to make it consistent with EPA’s approach to RFP and

treatment of sources outside th e nonattainment area in the upcoming final 2008 ozone SIP requirements rule

. Our suggested revision to this section reads as follows:

“4 . Geographic coverage of emission sources for RFP

EPA is proposing that the RFP demonstration to be included with a s tate’s PM2.5 nonattainment area plan must include emissions only for sources located in the nonattainment area, and not from an area larger than the nonattainment area. This policy approach differs from the remanded 2007 PM2.5 implementation rule. This se ction describes the evolution of policy on a similar RFP issue in the ozone NAAQS implementation program, and it discusses the reasoning behind this revised approach for PM2.5.

In the preamble to the remanded 2007 PM 2.5 Implementation Rule (which provided guidance for states on implementing the 1997 PM 2.5 NAAQS), the EPA allowed states to incorporate reductions of NO
x and SO 2 emissions up to 200 km from outside the nonattainment area (and potentially for reductions of VO C or ammonia) into their RFP plan when certain conditions were met. This policy was included in the 2007 PM 2.5 Implementation R ule in part to be consistent with a similar RFP policy for NOx and VOC that was included in the November

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- 2005 Phase 2 ozone NAAQS implementation rule which provided guidance for states on implementing the 1997 ozone NAAQS

. 1

Note that under the policy in the 2007 PM 2.5 I mplementation R ule, if a state intended to include emission reductions from outside the nonattainment area in the RFP plan, t he state would need to take on the additional work associated with developing 1) an expanded baseline emissions inventory for the entire geographic area ( i.e. , the nonattainment area plus the additional area outside the nonattainment area) that characteriz es emissions for all stationary, area, and mobile sources (rather than for just a select few stationary sources) in the overall area; and 2) a projected attainment year inventory for this expanded area outside the boundaries of the designated nonattainment area. By requiring inclusion of all types of sources in these “expanded area” emission inventories, the EPA intended for this approach to reflect the projected net emissions reductions in this area (the difference between the “expanded area” base year

invento ry and the projected attainment year inventory). However, it should be noted that for a state to develop these more extensive inventories, it would likely involve a substantial amount of additional time and resources. In addition, the state would need to p rovide information supporting their decision regarding how far outside the nonattainment area the RFP inventory should extend. While this “outside the nonattainment area” RFP approach was theoretically available to states in developing their PM 2.5 attainme nt plans that were due in 2008, there were no states that elected to follow this approach.

Both the 2005 Phase 2 ozone implementation rule and the 2007 PM2.5 implementation rule were challenged on several issues. With regard to the Phase 2 ozone implem entation rule,

the EPA granted a petition for reconsideration and ultimately issued a final notice of

reconsideration in June 2007. In November 2008, the U.S. Court of Appeals for the D.C. Circuit heard oral argument concerning multiple petitions for judicial review of the Phase 2 ozone rule and the notice of reconsideration. One of the issues in this case involved whether compliance by electric generating units (EGUs) with a regional emissions trading program could be considered to meet the RACT requirement f or those sources located in a nonattainment area. In its July 2009 decision, the Court emphasized that: ‘‘the RACT requirement calls for reductions in emissions from sources in the area; reductions from sources outside the nonattainment area do not satisfy the requirement . . . Accordingly, participation in the NOx SIP call would constitute RACT only if participation entailed at least RACT

- level reductions in emissions from sources within the

nonattainment area.’’

In light of this court decision, the EPA has determined that the best reading of the statute would be to interpret the term “sources in the area” in the same manner where it appears in different nonattainment provisions for ozone. The term appears in section 182 (requirements for

ozone nonattainment areas) with regard to RFP as well as RACT. The NRDC decision found that section 182(b)(2) requires that a SIP must provide for implementation of RACT (under section 172(c)) for emissions sources “in the area,” meaning in the nonattainment area. In a consi stent manner, EPA believes that when section 182(b)(1)(A)

- (B) defines baseline emissions for RFP as

1 See Phase 2 Ozone Implementation rule, 70 FR 71612, November 29, 2005.

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- “the total amount of actual VOC or NOx emissions from all anthropogenic sources in the area,”

this also means sources “in the nonattainment area.”

With re gard to the 2007 PM2.5 implementation rule, the EPA received a petition for reconsideration in June 2007 that raised objections on several issues. One such issue dealt with the EPA’s interpretation of the statutory RFP requirements to allow a state to take “credit” for emissions reductions from outside the nonattainment area when addressing RFP in its attainment plan. 2 The EPA granted the petition for reconsideration on this issue in 2010, after the D.C. Circuit issued its decision on the Phase 2 Ozone Impl ementation Rule. 3

, 4

Specifically, the EPA believes that the D.C. Circuit’s interpretation of the phrase “sources in the area” applies to RACT and RFP requirements for both the ozone NAAQS and the

PM 2.5 NAAQS. In particular, for PM 2.5 , the statutory language at section 171(1) defines RFP in terms of “reductions in emissions” required in an attainment plan, which the EPA interprets as being directly linked to the baseline emissions inventory for sources l ocated in a PM 2.5 nonattainment area. The baseline emissions inventory is the foundation for the attainment plan. The emissions inventory requirement of section 172(c)(3) explicitly requires that the attainment plan inventory include all sources of the rel evant pollutants “in such area,” which is a clear reference to the designated nonattainment area. Given that the baseline inventory must reflect the emissions “in such area,” and that this inventory provides the starting point for a state’s RFP analysis, i n which the state must calculate generally linear progress in emissions reductions that will lead to attainment of the NAAQS in the area, the EPA believes it is appropriate that a state

should focus on sources located within the nonattainment area when con ducting its analysis to determine the annual emissions reductions necessary for demonstrating RFP.

EPA believes that the most appropriate approach with regard to the geographic area required to be covered for demonstrating RFP in a PM2.5 attainment plan also should be limited to the nonattainment area for two other reasons. First, EPA believes that it makes policy sense for the PM2.5 implementation rule approach to be consistent with the approach in the ozone implementation rule. In the past, a number of areas have been designated as nonattainment for both standards, and the nonattainment area boundaries often are the same. For such areas, a common policy approach for the geographic area covered by the RFP plan will be more efficient to implement and would be expected to be less burdensome for the air agency than if the geographic areas covered by RFP plans for the two pollutants differed.

2 This same petition raised concerns regarding the criteria used to determine the economic feasibility of controls being considered for RACT for the 1997 PM 2.5 NAAQS. See “Petition for Reconsideration,” filed by Paul Cort, Earthjustice, on behalf of the American Lung Association, Medical Advocates for Healthy Air, Natural Resources Defense Council, and the Sierra Club (June 25, 2007). A copy of the petition is in the docket for this action.

3 L e tter dated May 13, 2010

, from Gina McCarthy to David S. Baron and Paul Cort, Earthjustice. A copy of the letter is located in the docket for this action.

4 See NRDC v. EPA , 571 F.3d 1245 (D.C. Cir. 2009).

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- Second, a policy allowing the geographic area of the RFP plan to be larger than the

nonattainment area would conflic t with a key provision of subpart 4 which requires annual incremental reductions in emissions from sources within the nonattainment area. Under subpart 4, an area that fails to attain the standard by the Serious area attainment date is then subject to the provisions of section 189(d). Section 189(d) specifies that the state must submit a plan revision within 12 months which provides for “an annual reduction in PM

– 10 or PM

– 10 precursor

emissions within the area of not less than 5 percent of the amount of suc h emissions as reported in the most recent inventory prepared for such area ” (emphasis added)

. The EPA does not believe the rule should include an RFP policy approach which would not be consistent with section 189(d).

After reconsideration of the approach to RFP that was oppo sed in the petition for

reconsideration of the 2007 PM 2.5 Implementation Rule, and in light of the D.C. Circuit decision on the Ozone Phase 2 Implementation Rule, the EPA believes the best reading of the statute is

that the CAA does not allow for a state to include emissions reductions from sources outside a nonattainment area when developing the plan to meet the CAA section 172(c)(2) RFP requirements for a PM 2.5 nonattainment area. The EPA seeks comment on this proposed

app roach.”

14. Emission inventory.

a. Initial Comment : Commenter recommends developing a mechanism to allow for the use of emissions estimating methodologies (EEM) for animal production operations under the National Air Emissions Monitory Study (NAEMS) when they become available.

Response on 1/23/2015 : The current draft proposed rule already promotes the use of the best available data, which would include EEMs based on the NAEMS data if and when such methodologies become available for estimating emissions from animal production operations. As described on page 9 8 , CAA section 172(c)(3) requires a “comprehensive, accurate, and current inventory of actual emissions,” and the preamble further stresses that the “specific attainment plan requirements for the P M2.5 NAAQS set forth in section 189(a) and associated modeling requirements make an accurate and up

- to

- date emissions inventory a critical element of any viable attainment plan.” The current draft also continues on page 9 8 to say that “States should use th e best available, current emissions inventory information for attainment plan development, because high quality emissions inventory data are essential for the development of an effective control strategy.” Thus, it should be evident (without explicitly pro viding the suggested details in this rule) that new approaches such as the future EEMs using NAEMS data would be an option when such methodologies become available.

Furthermore, there are countless other emissions categories and countless associated

emiss ions estimating approaches that could be used for estimating the emissions from these sources. To ensure that the approaches remain flexible and up

- to

- date, the emissions inventory guidance has traditionally been the place to address such specific recommen dation methodologies, and this is the approach that we recommend in this case as well. It is unnecessary and infeasible to address all of the current and possible future approaches for

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- every source category in this rulemaking notice, nor would we do so for a single source

category.

New Comment : During a 2/5/2015 conference call with interagency representatives, it was

decided that a few sentences should be added about ammonia emissions to the emission inventory section in the preamble.

Response : EPA has added additional text on ammonia emissions in the section below. The

recommended underlined text would appear around page 108. The overall section is included

for context.

“ 5. Why is the EPA requiring certain pollutants be included in the inventories?

Th e EPA is proposing that states must submit emissions inventories that include all

emissions of direct PM 2.5 and all emissions of all PM 2.5 precursors: SO 2 , NO
x , VOC and ammonia. Furthermore, the inventory must differentiate between the condensable and filt erable portions of direct PM 2.5 emissions. Section II.B of this proposal describes the background needed to understand the importance of including these precursors in emissions inventories for attainment plan purposes for the PM 2.5 NAAQS . Emissions information about PM 2.5 and its precursors is a necessary precondition to meeting other core attainment plan requirements, such as effective evaluation of control measures and adequate demonstration of projected future attainment of the NAAQS through model ing. The EPA notes that with respect to requiring states

to include emissions of direct PM 2.5 and PM 2.5 precursors in emissions inventories, the agency is following the requirements it has established for the PM 2.5 NAAQS in the past. Section 172(c)(3) expl icitly requires states to submit a “comprehensive, accurate, and current inventory of actual emissions of the relevant pollutants” and the EPA concludes that in order to meet these basic statutory requirements for the PM 2.5 NAAQS, states must address PM 2.5 and all PM 2.5 precursors in their emissions inventories. The EPA requires air agencies to use the best available methodologies for estimating emissions of direct PM 2.5 and its precursors. It should be noted that for ammonia, in particular, updated emission estim ating methodologies for animal feeding operations are under development using data collected during 2007

- 2009 from representative operations pursuant to the National Air Emissions Monitoring Study. The EPA is hopeful that such updated methodologies will he lp reduce uncertainties in current ammonia inventories and will improve the quality of future emissions inventories needed for implementing the PM 2.5 NAAQS. ”

16. Quantitative milestones.

a. Initial Comment : R eviewer r ecommend s allowing a nonattainment area that has decreased emissions by greater than 15 percent within a 3 year period to carryover that additional decreased emission to the next quantitative milestone.

Response : To address this comment, we have added the sente nce below to the paragraph on page 34 5 :

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- “Although section 189(d) requires that a state develop measures that will obtain annual emissions reductions of “not less than 5 percent” from the most recent inventory, the EPA interprets this language to authoriz e states to elect to front

- load emissions reductions in earlier years and still meet the 5 percent per year requirement. The EPA believes that interpreting the statute in this way will encourage states to implement measures earlier, where possible, rather than delay implementation of measures merely to assure that the 5 percent requirement can be met in later years. Early reductions of this kind would also be accounted for in state submittals to show they are meeting quantitative milestones every three

year s. Consistent with its past action to approve a Serious area nonattainment plan for the San Joaquin Valley (CA) PM 10 nonattainment area under section 189(d), the EPA therefore proposes and seeks comment on an approach to allow states to carry forward any e missions reductions beyond the required minimum 5 percent in a given year to the next year as a means to encourage states to achieve emissions reductions as quickly as possible. 5

New Comment : On a 2/2/2015 conference call, reviewers suggested including a dditional

clarification on this issue.

EPA Response : We have now changed the underlined sentence to read:

“Thus, using the example described above, the annual reduction requirement for the area would be 5 tons/day from a base year emissions level of 100 tons/day. The required level after year 1 would be 95 tons/day, after year 2 the level would be 90 tons/day, and so on. If the air agency reached a level of 81 tons/day by the end of year 3, then by the end of year 4 it would only need to reduce emissions by 1 ton/day to yield an emi ssions level of 80 tons/day.”

20. Major source thresholds for PM 2.5 precursors.

c. Initial Comment : Re viewer re commend s modifying EPA’s policy on preferred ratios for major source threshold determinations for PM 2.5 precursors related to sulfur dioxide ( SO 2 )

and nitr ogen oxides ( NO X ) . Specifically, the EPA believes that the preferred ratios in the

2008 PM 2.5 NSR Rule were not conservative enough (page 374). However, not considering the relative effect of PM 2.5 precursors to direct PM 2.5 puts an undue burden on

poten tial sources of PM 2.5 precursors and sets a de facto more protective air quality

standard than for direct PM 2.5 sources

.

Initial Response : It is not clear what is meant by “modifying EPA’s policy on preferred ratios for major source threshold determinations....” As explained in the draft preamble, the policy on preferred ratios that the EPA set forth in the 2008 PM2.5 NSR Implementation Rule was developed “ for purposes of interpollutant offset trading, whereby a source could obtain reductions of a PM 2.5 precursor to offset an increase of

direct PM 2.5 emissions or another PM 2.5 precursor based on the “preferred” offset ratios.” Arguably, such ratios , if approvable, could potentially also have been applied to the

5 69 FR 30006 ( May 26, 2004 )

.

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- setting of major source thresholds f or the individual PM2.5 precursors

. However, we indicated in a subsequent 2011 memo that we could no longer support the preferred offset ratios as being presumptively approvable in state implementation plans. 6 Similarly, while we generally agree with the c omment that precursor thresholds should reflect the relative effect of the individual precursor on ambient PM2.5 levels, we do not currently have a sufficient technical basis to prescribe specific higher thresholds by rule . We believe that the preamble ade quately explains the technical and legal impediments and requests public

comments as to how to best address this issue.

New Comment : Commenter recommends further clarification of these issues.

Response : EPA has revised this section (around page 392 and 394 ) to read:

“ Moreover, the EPA believes that a reasonable argument can be made that whatever

threshold is set for PM 2.5 emissions, the same level would be too low to be regarded as “major” for each precursor when considering the effects that such precursor sources could have on ambient PM 2.5 concentrations. The EPA previously analyzed the relationship between emissions of SO 2 and NO
x and the formation of secondary PM 2.5 in

the ambient air expressly for purposes of determining an appropriate ratio for allowing interprecursor offsets for PM 2.5 . Those studies resulted in the EPA providing in the 2008

PM 2.5 NSR Rule “preferred” ratios for both SO 2 and NO
x , whereby a source could obtain

reductions of a PM 2.5 precursor to offset an increase of direct PM 2 .5 emissions or another

PM 2.5 precursor based on the “preferred” offset ratios. 7 In brief, the preferred ratios were

as follows: for NO
x - to

- primary PM 2.5 : 200 to 1 (NO
x tons to PM 2.5 tons) for areas in the eastern U.S, and 100 to 1 for areas in the western U.S.; and for SO 2

- to

- primary PM 2.5 : 40 to 1 (SO 2 tons for PM 2.5 tons). In each case, the ratio illustrates that it requires considerably more precursor emissions than direct PM 2.5 emissions to result in a particular ambient concentration of PM 2.5

. It shou ld be noted that at that time the EPA did not consider using the preferred ratios for the purpose of adjusting the major source thresholds or significant emissions rates for SO 2 and NOx when regulating as PM 2.5

precursors. ”

6 See memorandum from Gina McCarthy, EPA Assistant Administrator for Air and

Radia tion, to Regional Office Air Division Directors, “ Revised Policy to Address Reconsideration of Interpollutant Trading Provisions for Fine Particles (PM2. 5 ) , issued on July

2 1, 2011. The memo indicated that, “First, upon re

- examination of the original data, we believe that the original preferred ratios are not sufficiently representative of conditions in all areas of the country..... Second, we have determined that the ratios defined in the 2008 preamble are generally not suitable for application to offsets th at address violations of the 24

- hour primary PM2.5 NAAQS.”

7 The technical assessment, with details on data and modeling inputs, was fully described in a technical memo titled “Details on Technical Assessment to Develop Interpollutant Trading

Ratios for PM 2.5 Offsets,” which was placed in the docket to the 2008 final rule. See also 73 FR

28339.

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- ...

“ The EPA does not believe that a sufficient technical basis exists at this time to enable the agency to propose specific higher major source thresholds for any of the four PM 2.5 precursors presumptively regulated in PM 2.5 nonattainment area s

. ”

23. EO 12866 and EO 13563

.

d. Initial Comment : Reviewer recommends providing benefits and costs for this proposed rule within a regulatory impact analysis even if those benefits and costs

are at the state level.

Response : A Regulatory Impact Assessment (RIA) was developed for the 2012 PM2.5 NAAQS. As has traditionally been done for NAAQS rulemakings, the EPA conducted this RIA to provide the public with illustrative estimates of the potential costs and health and welfare benefits of attaining the revised annual

standard. This document is available o n the PM2.5 NAAQS website at: http://www.epa.gov/ttn/ecas/regdata/RIAs/finalria.pdf

.

EPA commonly provide s a regulatory impact analysis for NAAQS revisions, but

not for implementation rules.

Comment : Reviewer requests adding a reference to the RIA to this section.

Response : We have now added a footnote to this section, which reads:

“Note that a regulatory impact analysis evaluating the costs and benefits associated with attaining the 2012 PM2.5 NAAQS was released at the time the NAAQS review was finalized. See “Regulatory Impact Analysis for the Final Revisions to the National Ambient Air Quality Standards for Particulate Matter.” U.S. Environmental Protection Agency, Office of Ai r Quality and Planning Standards, Health and Environmental Impacts Division, February 28, 2013. EPA

452/R

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- 005.”

Additional Comments Received on 2/10/2015

1. Comment : Reviewer recommends providing additional information on whether food security, the ava ilability of an abundant and affordable food supply, and ecosystem impacts, in addition to technical and economic feasibility and adverse environmental or energy effects, in determining the “reasonableness” of mitigation/control options, especially in rela tion to ammonia. This relates to page 54, and the use of term “additional reasonable measures” to identify additional measures that are not included in RACM and

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- EPA’s response to comments that PM10 and ozone programs do not have this term as those program s already include specific requirements.

Response : Our response to this suggestion from the reviewer ( to add additional factors for states to consider in determining technological and economic feasibility of potential control measures) is similar to the r esponse we have provided on pages 3

- 4 above regarding suggested chang es to the factors for economic feasibility. The set of factors to be considered by states in determining “reasonable” control measures is described in depth in pages 120

- 150 in section 2 . Identification and selection of RACM and RACT and

additional reasonable measures. These factors are taken from long

- standing guidance (the 1992 General Preamble) that is applicable to implementation of more than just the PM NAAQS. We think the guidance has proven sufficiently broad and has provided adequate flexibility to states to be able to present reasoning to demonstrate why certain

facilities may or may not be able to afford control technology used on similar sources. For example, it appears that an issue such as food security could be addressed under economic factors in existing guidance dealing with product supply and product prices. As indicated before, w e think that changing within this preamble the longstanding guidance that has applied to all N AAQS risks introducing confusion to states in their attainment planning process es for this NAAQS and for other NAAQS as well, with little potential gain in return.

2. Comment : Reviewer recommends providing additional clarification on why PM10 requirements for control measures guidance documents do not apply to PM2.5, as PM2.5 is a subset of PM10 (one of the bases for the regulating PM2.5 under Subpart 4). If the previous statement is correct, should the requirements for PM2.5 be the same as PM10?

Response : Section 190 was included in the 1990 Clean Air Act Amendments, and it directed EPA to issue guidance on RACM and BACM for three important source categories

– urban fugitive dust, residential wood combustion, and prescribed burning

– which were identified at that time as key contributors to high concentrations of PM10 (which at the time was the only PM

- related NAAQS in effect). EPA issued guidance on those topics at that time and has fulfilled this statutory requirement. M oreover, m uch has been learned in the scientific and air quality management communities in the past twenty years to inform the actions of air agencies as they develop control strategies to attain

PM2.5 stand ards. We do not believe the control measu re requirements for PM2.5 should

be the same as for PM10. PM2.5 is a much more complex pollutant than PM10, and

many new and/or more cost

- effective emission reduction technologies and management techniques exist today that did not exist in the 1990’s. The Act does not require EPA to update the 1990 guidance for either PM

- 10 or PM

- 2.5, and EPA does not plan to do so at this time. However we will assist states in the development of their RACM and BACM plans.

3. Comment : Reviewer recommends providing additional discussion on ammonia as the primary sources of amm onia are currently identified in the EPA’s National Emissions Inventory to be “livestock raising” (54%) and “fertilizer application”

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- (27%). Specifically, given that ammonia emissions from these sources are primarily driven by biological activity and meteo rology, which have generally less opportunity for human control than chemical or mechanical processes, how is this rela tive lack of ability for human control into control technologies for these sources incorporated within mitigation and control options? C an these limitations be included in a state’s determination of “reasonableness” or “feasibility”?

4. Comment : Reviewer recommends providing additional clarification as ammonia is a reactive nitrogen species with multiple environmental pathways, how is the po tential for other nitrogen

- related environmental impacts from reactive nitrogen due to potential

ammonia controls evaluated? Is this an aspect that can be considered in a “reasonableness” determination as related to adverse environmental impacts? How are ammonia air emission impacts weighed in relation to potential water quality or other environmental impacts?

Response to Comments 3 and 4 : We understand that there are specific issues that arise when considering potential emission reduction strategies for ammonia. However, it can be argued that specific issues arise when considering control measures for many other categories of emissions as well. T he preamble sections on RACT/RACM and

BACT/BACM both include an extensive discussion of the general framework for air agencies to follow in considering a range of factors in determining economic and technological feasibility of control measures , in order to make judgments about what

measures could be “ reasonable ” for a particular nonattainment area. For example, o n page 135 of the draft preamble, it states:

“ Furthermore, the EPA believes that reducing air emissions may not justify adversely affecting other resources, for example, by increasing pollution in bodies of water, creating additional solid waste disposal problems or creating excessive energy demands. An otherwise available control technology may not be reasonable if these other environmental impacts are sufficiently adverse and cannot reasonably be mitigated. The EPA proposes that a state may

consider a co ntrol measure for direct PM 2.5 or a PM 2.5 precursor not reasonable if, considering the availability of mitigating adverse impacts of that control on pollution of other media, the control would not, in the state's reasoned judgment, provide a net benefit to public

health and the environment. It sh ould be noted that, in many past situations, states and owners of existing sources have adopted control technologies for direct PM 2.5 and /or PM 2.5 precursors with known energy penalties and some adverse effects on other media, based on the reasoned judgmen t that installation of such technology would result in a net benefit to public health and the environment. States should consider this before determining that a control technology is not reasonable because it may have other, negative environmental impacts that are, on balance, marginal.”

State implementation plans will address ammonia and other precursor issues on a case

- by

case basis, as supported by the state’s reasoned judgment. As indicated in our initial set of

responses, w e think the existing guidance on economic and technological feasibility of

control measures has proven sufficiently broad and has provided adequate flexibility to states

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- to be able to present reasoning to demonstrate why certain facilities are not able to afford

control techno logy used on similar sources. W e think that changing within this preamble the longstanding guidance that has applied to all NAAQS risks introducing confusion to states in their attainment planning process es for this NAAQS and for other NAAQS as well, with little potential gain in return. In addition, t he EPA does not believe it would be effective to

include a series of subsections in this guidance , each providing specific guidance and specific factors for developing control measures for just a single speci fic category of emissions. To structure the document this way would result in a much larger and even more complex rulemaking, and simply would not be feasible. For this reason, we do not recommend adding any additional text to the preamble in response to c omments 3 and 4.

Precursor Policy Options

1. Comment : Reviewer recommends providing clarification relating to PM2.5 precursor

demonstration. Specifically, when conducting a PM2.5 precursor demonstration, would a state only consider emissions of a precurso r in a nonattainment area for this

demonstration? In this instance, is it assumed that if emissions of a precursor in the nonattainment area are not significant, then the state would not need to consider emissions of the PM2.5 precursor outside the nonatt ainment area unless attainment could

not be demonstrated otherwise?

Response : Yes, the precursor demonstration options would be based on the evaluation of precursor emissions only from the nonattainment area. And yes, if emissions of a precursor in the n onattainment area are determined to not contribute significantly to PM2.5 levels in the area that exceed the standard, then the state would not need to consider emissions of the PM2.5 precursor outside the nonattainment area unless attainment by the Modera te area attainment date could not be demonstrated otherwise. We feel the preamble in the precursor section clearly states that the proposed options for evaluating significance are to be based on emissions from within the nonattainment area;

for this reason , we do not think changes to the preamble are needed on this issue.