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Proposed Rule

Approval and Promulgation of Implementation Plans; Iowa; Regional Haze State Implementation Plan

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Start Preamble

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing approval of a revision to the Iowa State Implementation Plan (SIP) submitted by the State of Iowa on July 16, 2013. Iowa's July 16, 2013, SIP submission (“progress report SIP”) addresses requirements of the Clean Air Act (CAA or Act) and EPA's rules that require states to submit periodic reports describing progress towards reasonable progress goals (RPGs) established for regional haze and a determination of the adequacy of the state's existing SIP addressing regional haze (“regional haze SIP”). EPA is proposing approval of Iowa's progress report SIP submission on the basis that it addresses the progress report and adequacy determination requirements for the first implementation period for regional haze.

DATES:

Comments must be received on or before August 4, 2014.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-R07-OAR-2014-0365 by one of the following methods:

1. www.regulations.gov: Follow the on-line instructions for submitting comments.

2. Email: harper.jodi@epa.gov.

3. Mail or Hand Delivery or Courier: Ms. Jodi Harper, Air Planning and Development Branch, Air and Waste Management Division, U.S. Environmental Protection Agency, Region 7, 11201 Renner Boulevard, Lenexa, Kansas 66219.

Instructions: Direct your comments to Docket ID No. EPA-R07-OAR-2014-0365. EPA's policy is that all comments received will be included in the public docket without change and may be Start Printed Page 37977made available online at www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through www.regulations.gov or email. The www.regulations.gov Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to EPA without going through www.regulations.gov, your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket. All documents in the electronic docket are listed in the www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in www.regulations.gov or in hard copy at the Environmental Protection Agency, Air Planning and Development Branch, 11201 Renner Boulevard, Lenexa, Kansas 66219. EPA requests that you contact the person listed in the FOR FURTHER INFORMATION CONTACT section to schedule your inspection. The interested persons wanting to examine these documents should make an appointment with the office at least 24 hours in advance.

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FOR FURTHER INFORMATION CONTACT:

Ms. Jodi Harper, Air Planning and Development Branch, Air and Waste Management Division, U.S. Environmental Protection Agency, Region 7, 11201 Renner Boulevard, Lenexa, Kansas 66219 at (913) 551-7483 or by email at harper.jodi@epa.gov.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Throughout this document “we,” “us,” or “our” refer to EPA. This section provides additional information by addressing the following:

I. What is the background for EPA's proposed action?

II. What are the requirements for the regional haze progress report SIPs and adequacy determinations?

A. Regional Haze Progress Report SIP

B. Adequacy Determination of the Current Regional Haze SIP

III. What is EPA's analysis of Iowa's progress report SIP and adequacy determination?

A. Regional Haze Progress Report SIPs

1. 40 CFR 51.308(g)(1)

2. 40 CFR 51.308(g)(2)

3. 40 CFR 51.308(g)(3)

4. 40 CFR 51.308(g)(4)

5. 40 CFR 51.308(g)(5)

6. 40 CFR 51.308(g)(6)

7. 40 CFR 51.308(g)(7)

B. Determination of Adequacy of Existing Regional Haze Plan

IV. What action is EPA proposing to take?

I. What is the background for EPA's proposed action?

States are required to submit a progress report in the form of a SIP revision every five years that evaluates progress towards the RPGs for each mandatory Class I Federal area within the state and in each mandatory Class I Federal area outside the state which may be affected by emissions from within the state. 40 CFR 51.308(g). States are also required to submit, at the same time as the progress report, a determination of the adequacy of the state's existing regional haze SIP. 40 CFR 51.308(h). The first progress report SIP is due five years after submittal of the initial regional haze SIP. On March 25, 2008, the Iowa Department of Natural Resources (IDNR) submitted the state's first regional haze SIP in accordance with 40 CFR 51.308(b).[1]

On April 4, 2013, IDNR provided to the Federal Land Managers, a revision to Iowa's SIP reporting on progress made during the first implementation period toward RPGs for Class I areas in the state and Class I areas outside the state that are affected by emissions from Iowa's sources. There are no Class I areas located in the State of Iowa. Notification was published in the Legal Notices section of the Des Moines Register on May 9, 2013. A public hearing was held on June 11, 2013, at the Air Quality Bureau in Windsor Heights, and the public comment period ended on June 12, 2013.

On July 16, 2013, IDNR submitted the SIP to EPA. This progress report SIP and accompanying cover letter also included a determination that the state's existing regional haze SIP requires no substantive revision to achieve the established regional haze visibility improvement and emissions reduction goals for 2018. EPA is proposing to approve Iowa's progress report SIP on the basis that it satisfies the requirements of 40 CFR 51.308(g) and 51.308(h).

II. What are the requirements for the regional haze progress report SIPs and adequacy determinations?

A. Regional Haze Progress Report SIP

Under 40 CFR 51.308(g), states must submit a regional haze progress report as a SIP revision every five years and must address, at a minimum, the seven elements found in 40 CFR 51.308(g). As described in further detail in section III below, 40 CFR 51.308(g) requires a description of the status of measures in the approved regional haze SIP; a summary of emissions reductions achieved; an assessment of visibility conditions for each Class I area in the state; an analysis of changes in emissions from sources and activities within the state; an assessment of any significant changes in anthropogenic emissions within or outside the state that have limited or impeded progress in Class I areas impacted by the state's sources; an assessment of the sufficiency of the approved regional haze SIP; and a review of the state's visibility monitoring strategy.

B. Adequacy Determinations of the Current Regional Haze SIP

Under 40 CFR 51.308(h), states are required to submit, at the same time as the progress report SIP, a determination of the adequacy of their existing regional haze SIP and to take one of four possible actions based on information in the progress report. As described in further detail in section III below, 40 CFR 51.308(h) requires states to either: (1) Submit a negative declaration to EPA that no further substantive revision to Start Printed Page 37978the state's existing regional haze SIP is needed; (2) provide notification to EPA (and other state(s) that participated in the regional planning process) if the state determines that its existing regional haze SIP is or may be inadequate to ensure reasonable progress at one or more Class I areas due to emissions from sources in other state(s) that participated in the regional planning process, and collaborate with these other state(s) to develop additional strategies to address deficiencies; (3) provide notification with supporting information to EPA if the state determines that its existing regional haze SIP is or may be inadequate to ensure reasonable progress at one or more Class I areas due to emissions from sources in another country; or (4) revise its regional haze SIP to address deficiencies within one year if the state determines that its existing regional haze SIP is or may be inadequate to ensure reasonable progress in one or more Class I areas due to emissions from sources within the state.

III. What is EPA's analysis of Iowa's regional haze progress report and adequacy determination?

On July 16, 2013, IDNR submitted a revision to Iowa's regional haze SIP to address progress made towards RPGs of Class I areas in the state and Class I areas outside the state that are affected by emissions from Iowa's sources. This progress report SIP also included a determination of the adequacy of the state's existing regional haze SIP. Iowa has no Class I areas within its borders. IDNR utilized particulate matter source apportionment (PSAT) techniques for photochemical modeling conducted by the Central Regional Air Planning Association (CENRAP) to identify four Class I areas in two nearby states potentially impacted by Iowa sources: Boundary Waters Canoe Area Wilderness (BOWA) and Voyagers National Park (VOYA) in Minnesota, and Isle Royale National Park (ISLE) and Seney Wilderness Area (SENE) in Michigan. Collectively these four Class I areas are referred to as the Northern Midwest Class I areas. 77 FR 11979.

A. Regional Haze Progress Report SIPs

The following sections summarize: (1) Each of the seven elements that must be addressed by the progress report under 40 CFR 51.308(g); (2) how Iowa's progress report SIP addressed each element; and (3) EPA's analysis and proposed determination as to whether the state satisfied each element.

1. 40 CFR 51.308(g)(1)

40 CFR 51.308(g)(1) requires a description of the status of implementation of all measures included in the regional haze SIP for achieving RPGs for Class I areas both within and outside the state.

Iowa evaluated the status of all measures included in its 2008 regional haze SIP in accordance with 40 CFR 51.308(g)(1). Specifically, in its progress report SIP, Iowa summarizes the status of the emissions reduction measures that were included in the final iteration of the Central Regional Air Planning Association (CENRAP) regional haze emissions inventory and RPG modeling. Iowa also discusses the status of those measures that were not included in the final CENRAP emissions inventory and were not relied upon in the initial regional haze SIP to meet RPGs. The state notes that the emissions reductions from these measures, which are relied upon by Iowa for reasonable progress, will help ensure Class I areas impacted by Iowa sources achieve their RPGs. The measures include applicable Federal programs (e.g., mobile source rules, Maximum Achievable Control Technology (MACT) standards, Federal and state consent agreements, and Federal and state control strategies for electric generating units (EGUs)). This summary includes a discussion of the benefits associated with each measure.

EPA proposes to find that Iowa's analysis adequately addresses 40 CFR 51.308(g)(1). The state documents the implementation status of measures from its regional haze SIP as well as describes significant measures resulting from EPA regulations other than the regional haze program as they pertain to the state's sources. The progress report SIP highlights the effect of several Federal control measures both nationally and in the CENRAP region, and when possible, in the state.

Regarding the status of BART and reasonable progress control requirements for sources in the state, Iowa's progress report SIP notes that no non-EGU BART sources were found to be BART eligible and therefore, no BART specific emissions limits were developed. Additionally, Iowa summarized its reasonable progress control determinations from its regional haze SIP. Because the state found no additional controls to be reasonable for the first implementation period for sources evaluated for reasonable progress in Iowa, no further discussion of the status of controls was necessary in the progress report SIP.

EPA proposes to conclude that Iowa has adequately addressed the status of control measures in its regional haze SIP as required by 40 CFR 51.308(g)(1). Iowa describes the implementation status of measures from its regional haze SIP, including the status of control measures to meet BART and reasonable progress requirements, the status of significant measures resulting from EPA regulations, as well as measures that came into effect since the CENRAP analyses for the regional haze SIP were completed.

2. 40 CFR 51.308(g)(2)

40 CFR 51.308(g)(2) requires a summary of the emissions reductions achieved in the state through the measures subject to 40 CFR 51.308(g)(1).

In its regional haze SIP and progress report SIP, Iowa focuses its assessment on NOX and SO2 emissions from EGUs because available information from multiple sources (CENRAP, CAIR provided by EPA's Clean Air Markets Division (CAMD), etc.) determined that these compounds accounted for the majority of the visibility-impairing pollution in the Central Region.

During the period from 2002-2011, SO2 emissions decreased in Iowa by 25 percent.[2] Also during that same period, NOX emissions decreased by 51 percent. Iowa noted that Integrated Planning Model (IPM) projections for the 2018 planning period indicated an anticipated increase in EGU SO2 emissions and decrease in EGU NOX emissions. Iowa notes that the 2011 actual SO2 and NOX EGU emissions were significantly below the projected 2018 values, representing SO2 and NOX emissions that are 37 percent and 41 percent below their 2018 projections. Iowa also noted that these decreases in emissions have occurred while actual heat input has increased, indicating the reductions reflect cleaner generation and not merely decreased electricity demand.

EPA proposes to conclude that Iowa has adequately addressed 40 CFR 51.308(g)(2). The state provides estimates, and where available, actual emissions reductions of NOX and SO2 from EGUs in Iowa that have occurred since Iowa submitted its regional haze SIP. Iowa appropriately focused on NOX and SO2 emissions from its EGUs in its progress report SIP because it previously identified these emissions as the most significant contributors to visibility impairment at those areas that Iowa sources impact. Given the large NOX and SO2 reductions at EGUs that have actually occurred, further analysis of emissions from other sources or other Start Printed Page 37979pollutants, was ultimately unnecessary in this first implementation period. Because no additional controls were found to be reasonable for reasonable progress for the first implementation period for evaluated sources in Iowa, EPA proposes to find that no further discussion of emissions reductions from controls was necessary in the progress report SIP.

3. 40 CFR 51.308(g)(3)

40 CFR 51.308(g)(3) requires that states with Class I areas provide the following information for the most impaired and least impaired days for each area, with values expressed in terms of five-year averages of these annual values:[3]

(i) current visibility conditions;

(ii) the difference between current visibility conditions and baseline visibility conditions; and

(iii) the change in visibility impairment over the past five years.

Iowa does not have any Class I areas within its boundaries, and as this section pertains only to states containing Class I areas, no further discussion is necessary. EPA proposes to conclude that Iowa has adequately addressed 40 CFR 51.308(g)(3).

4. 40 CFR 51.308(g)(4)

40 CFR 51.308(g)(4) requires an analysis tracking emissions changes of visibility-impairing pollutants from the state's sources by type or category over the past five years based on the most recent updated emissions inventory.

In its progress report SIP, Iowa presents data from a statewide emissions inventory developed for the year 2002 and compares this data to the National Emissions Inventory (NEI) version 2 (dated April 10, 2012), or simply the 2008 NEIv2. For both the 2002 dataset and the 2008 NEIv2 data, pollutants inventoried include volatile organic compounds, NOX, fine particulate matter, coarse particulate matter, ammonia, and SO2. The emissions inventories from both the 2002 dataset and the 2008 NEIv2 include the following: ammonia, area, fugitive dust, offroad and onroad mobile sources, stationary point sources, road dust, fires, and biogenic sources. The comparison of emissions inventory data shows that emissions of the key visibility-impairing pollutants identified by CENRAP for the central states, NOX and SO2, continued to drop from 2002 to 2008 (decreasing 68,109 and 37,380 tons, respectively). While not all emissions in Iowa contribute to visibility impairment at a Class I area, Iowa chose to include a complete statewide inventory containing emission rates for all anthropogenic and biogenic sources, however in the Midwest, point source emissions of NOX and SO2 are often more closely evaluated in the context of regional haze.

The comparison also shows that a projected increase in emissions of fine and coarse particulate matter occurred, but increased less than the projected amount. Actual increase in fine and course particulate matter emissions during that same time period was by 20,318 and 173,147 tons, respectively. This increase was driven almost entirely by fugitive dust emissions, and to a lesser extent the road dust sector for coarse particulate emissions. Iowa also noted that the 2002 fugitive dust and road dust emissions estimates represent values after the application of transport factors, while the 2008 data have not been similarly adjusted. While the transport factor discrepancy does not permit a precise comparison of the 2002 and 2008 fugitive dust and road dust emissions, Iowa notes that a crude evaluation is possible assuming a simple fifty percent reduction of the 2008 fugitive dust and road dust emissions as a surrogate for the application of county-level transport factors. This simple reduction would bring the 2008 fine particulate and coarse particulate fugitive and road dust emissions in line and generally below the 2002 values. Iowa further notes that such emissions from Iowa are not known to contribute significantly to visibility impairment at Class I areas.

EPA proposes to conclude that Iowa has adequately addressed 40 CFR 51.308(g)(4). While ideally the five-year period to be analyzed for emissions inventory changes is the time period since the current regional haze SIP was submitted, there is an inevitable time lag in developing and reporting complete emissions inventories once quality-assured emissions data becomes available. Therefore, EPA believes that there is some flexibility in the five-year time period that states can select. Iowa tracked changes in emissions of visibility-impairing pollutants using the 2008 National Emissions Inventory, the most recent updated inventory of actual emissions for the state at the time that it developed the progress report SIP. EPA believes that Iowa's use of the six-year period from 2002-2008 reflects a conservative picture of the actual emissions realized between 2002-2013, as in many cases, Iowa had already reached or surpassed their 2018 goals by 2008. There also is a general downward trend from 2002-2008, so it is likely additional NOX and SO2 emissions reductions occurred between the 2008 data and actual conditions in 2013.

5. 40 CFR 51.308(g)(5)

40 CFR 51.308(g)(5) requires an assessment of any significant changes in anthropogenic emissions within or outside the state that have occurred over the past five years that have limited or impeded progress in reducing pollutant emissions and improving visibility in Class I areas impacted by the state's sources.

In its progress report SIP, Iowa addresses the changes in anthropogenic emissions between the 2008 NEIv2 data and the 2018 projections from the initial regional haze SIP. Iowa noted that there have been significant reductions among anthropogenic emissions categories, and that during the period from 2002-2008, in many cases the emissions reductions had already dropped below the 2018 projections. An increase in ammonia (NH3) was noted, however, the actualized increase was less than the projected increase and Iowa is still on track to meet the 2018 NH3 emissions target. Iowa also noted that it is uncertain if this increase is a reasonable representation of actual emissions increases or if it is computational in nature, because of changes to the versions and inputs to the Carnegie Mellon University (CMU) NH3 emissions model. Iowa concluded that emissions reductions of all pollutants in 2008 were generally ahead of schedule or had already met the 2018 projections, and that no changes in anthropogenic emissions have limited or impeded progress in reducing pollutant emissions and improving visibility.

EPA proposes to conclude that Iowa has adequately addressed 40 CFR 51.308(g)(5). Iowa demonstrated that there are no significant changes in anthropogenic emissions that have impeded progress in reducing emissions and improving visibility in Class I areas impacted by Iowa sources. The state referenced its analyses in the progress report SIP identifying an overall downward trend in these emissions from 2002 to 2008. Further, the progress report SIP shows that Iowa is on track to meeting its 2018 emissions projections.

6. 40 CFR 51.308(g)(6)

40 CFR 51.308(g)(6) requires an assessment of whether the current regional haze SIP is sufficient to enable Iowa, or other states, to meet the RPGs Start Printed Page 37980for Class I areas affected by emissions from the state.

In its progress report Iowa states that it believes that the elements and strategies outlined in its original regional haze SIP are sufficient to enable Iowa and other neighboring states to meet all the established RPGs. To support this conclusion, Iowa notes that the actual 2011 EGU emissions of SO2 and NOX are already below the 2018 projected emissions (by 55,408 and 27,055 tons, respectively), with further decreases expected. In particular, Iowa notes that the emissions reductions already achieved in the 2007 to 2011 period and the additional reductions not accounted for in the original regional haze SIP (as discussed previously for purposes of 40 CFR 51.308(g)(1)) further support Iowa's conclusion that the regional haze SIP's elements and strategies are sufficient to meet the established RPGs.

EPA proposes to conclude that Iowa has adequately addressed 40 CFR 51.308(g)(6). EPA views this requirement as a qualitative assessment that should evaluate emissions and visibility trends and other readily available information, including expected emissions reductions associated with measures with compliance dates that have not yet become effective. Iowa referenced the improving visibility trends at affected Class I areas and the downward emissions trends in the state, with a focus on NOX and SO2 emissions from Iowa's EGUs that support Iowa's determination that its regional haze SIP is sufficient to meet RPGs for Class I areas outside the state impacted by Iowa sources. EPA believes that Iowa's conclusion regarding the sufficiency of the regional haze SIP is appropriate because of the calculated visibility improvement using the latest available data and the downward trend in NOX and SO2 emissions from EGUs in Iowa.

7. 40 CFR 51.308(g)(7)

40 CFR 51.308(g)(7) requires a review of the state's visibility monitoring strategy and an assessment of whether any modifications to the monitoring strategy are necessary. In its progress report SIP, Iowa summarizes the existing IMPROVE monitoring network and its intended continued reliance on IMPROVE for visibility planning. Iowa operates two IMPROVE Protocol sampling sites, one at Viking Lake State Park in southwestern Iowa, and the other at Lake Sugema Wildlife Management in southeastern Iowa.

EPA proposes to conclude that Iowa has adequately addressed the sufficiency of its monitoring strategy as required by 40 CFR 51.308(g)(7). Iowa reaffirmed its continued reliance upon the IMPROVE monitoring network.

B. Determination of Adequacy of Existing Regional Haze Plan

Under 40 CFR 51.308(h), states are required to take one of four possible actions based on the information gathered and conclusions made in the progress report SIP. The following section summarizes: (1) the action taken by Iowa under 40 CFR 51.308(h); (2) Iowa's rationale for the selected action; and (3) EPA's analysis and proposed determination regarding the state's action.

In its progress report SIP, Iowa took the action provided for by 40 CFR 51.308(h)(1), which allows a state to submit a negative declaration to EPA if the state determines that the existing regional haze SIP requires no further substantive revision at this time to achieve the RPGs for Class I areas affected by the state's sources. The basis for Iowa's negative declaration is the findings from the progress report (as discussed in section III.A of this action), including the findings that: NOX and SO2 emissions from Iowa's sources have decreased beyond original projections; and the NOX and SO2 emissions from EGUs in Iowa are already below the levels projected for 2018 in the regional haze SIP and are expected to continue to trend downward for the next five years. Based on these findings, EPA proposes to agree with Iowa's conclusion under 40 CFR 51.308(h) that no further substantive changes to its regional haze SIP are required at this time.

IV. What action is EPA proposing to take?

EPA is proposing approval of a revision to the Iowa SIP, submitted by the State of Iowa on July 16, 2013, as meeting the applicable regional haze requirements as set forth in 40 CFR 51.308(g) and 51.308(h).

Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this proposed action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

  • Is not a “significant regulatory action” subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);
  • does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
  • is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq.);
  • does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
  • does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);
  • is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997);
  • is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001);
  • is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA; and
  • does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this rule does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP is not approved to apply in Indian country located in the state, and EPA notes that it will not impose substantial direct costs on tribal governments or preempt tribal law.

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List of Subjects in 40 CFR Part 52

  • Environmental protection
  • Air pollution control
  • Carbon monoxide
  • Incorporation by reference
  • Intergovernmental relations
  • Lead
  • Nitrogen dioxide
  • Ozone
  • Particulate matter
  • Reporting and recordkeeping requirements
  • Sulfur oxides
  • Volatile organic compounds
End List of Subjects Start Signature

Dated: June 13, 2014.

Mark J. Hague,

Acting Regional Administrator, Region 7.

End Signature End Supplemental Information

Footnotes

1.  On June 26, 2012, EPA finalized a limited approval of Iowa's March 25, 2008, regional haze SIP to address the first implementation period for regional haze (77 FR 38006). In a separate action, published on June 7, 2012 (77 FR 33642), EPA finalized a limited disapproval of the Iowa regional haze SIP because of the State's reliance on the Clean Air Interstate Rule to meet certain regional haze requirements, which EPA replaced in August 2011 with the Cross-State Air Pollution Rule (CSAPR) (76 FR 48208 (Aug. 8, 2011)). In the aforementioned June 7, 2012, action, EPA finalized a Federal Implementation Plan (FIP) for Iowa to replace the State's reliance on CAIR with reliance on CSAPR. Following these EPA actions, the DC Circuit issued a decision in EME Homer City Generation, L.P. v. EPA (hereinafter referred to as “EME Homer City”), 696 F.3d 7 (D.C. Cir. 2012), vacating CSAPR and keeping CAIR in place pending the promulgation of a valid replacement rule. On April 29, 2014, the U.S. Supreme Court reversed the DC Circuit opinion vacating CSAPR, and remanded the case for further proceedings. EME Homer City, 572 U.S. 134 S. Ct. 1584. CAIR continues to remain in place.

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2.  See also sections III.A.4. and III.A.6. of this action.

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3.  The “most impaired days” and “least impaired days” in the regional haze rule refers to the average visibility impairment (measured in deciviews) for the twenty percent of monitored days in a calendar year with the highest and lowest amount of visibility impairment, respectively, averaged over a five-year period. 40 CFR 51.301.

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[FR Doc. 2014-15686 Filed 7-2-14; 8:45 am]

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