Air Plan Approval; ID; Regional Haze Plan for the Second Implementation Period

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R10-OAR 2024-0545; FRL-11879-01-R10]</DEPDOC> <SUBJECT>Air Plan Approval; ID; Regional Haze Plan for the Second Implementation Period</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Environmental Protection Agency (EPA). <HD SOURCE="HED">ACTION:</HD> Proposed rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The Environmental Protection Agency (EPA) is proposing to approve the Idaho regional haze State Implementation Plan (SIP) revision submitted on August 5, 2022, and supplemented on May 8, 2024. Idaho submitted the SIP revision to address the requirement to make reasonable progress toward the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility in certain national parks and wilderness areas. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before April 23, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R10-OAR-2024-0545 at <E T="03">https://www.regulations.gov.</E> For comments submitted at <E T="03">regulations.gov,</E> follow the online instructions for submitting comments. Once submitted, comments may not be edited or removed from <E T="03">regulations.gov</E> . For either manner of submission, the EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be confidential business information or other information the disclosure of which is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission ( <E T="03">i.e.,</E> on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section. For the full EPA public comment policy, information about confidential business information or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> John Chi, EPA Region 10, 1200 Sixth Avenue, Suite 155, Seattle, WA 98101, at (206) 553-1185 or <E T="03">chi.john@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document, the use of “we” and “our” means “the EPA.” <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background and Requirements for Regional Haze Plans</FP> <FP SOURCE="FP1-2">A. Regional Haze Background</FP> <FP SOURCE="FP1-2">B. Roles of Agencies in Addressing Regional Haze</FP> <FP SOURCE="FP-2">II. Requirements for Regional Haze Plans for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Identification of Class I Areas</FP> <FP SOURCE="FP1-2">B. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress</FP> <FP SOURCE="FP1-2">C. Long-Term Strategy for Regional Haze</FP> <FP SOURCE="FP1-2">D. Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">E. Monitoring Strategy and Other State Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">F. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">G. Requirements for State and Federal Land Manager Coordination</FP> <FP SOURCE="FP-2">III. The EPA's Evaluation of the Idaho Regional Haze SIP Revision for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Background on the Idaho First Implementation Period SIP Revision</FP> <FP SOURCE="FP1-2">B. The Idaho Second Implementation Period SIP Revision and the EPA's Evaluation</FP> <FP SOURCE="FP1-2">C. Identification of Class I Areas</FP> <FP SOURCE="FP1-2">D. Calculations of Baseline, Current, and Natural Visibility Conditions; Progress to Date; and the Uniform Rate of Progress</FP> <FP SOURCE="FP1-2">E. Long-Term Strategy for Regional Haze</FP> <FP SOURCE="FP1-2">F. Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">G. Monitoring Strategy and Other Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">H. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">I. Requirements for State and Federal Land Manager Coordination</FP> <FP SOURCE="FP-2">IV. Proposed Action</FP> <FP SOURCE="FP-2">V. Incorporation by Reference</FP> <FP SOURCE="FP-2">VI. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background and Requirements for Regional Haze Plans</HD> <HD SOURCE="HD2">A. Regional Haze Background</HD> In the 1977 Clean Air Act Amendments, Congress created a program  <SU>1</SU> <FTREF/> to protect visibility in the nation's mandatory class I Federal areas, which include certain national parks and wilderness areas. <SU>2</SU> <FTREF/> Congress established as a national goal the “prevention of any future, and the remedying of any existing, impairment of visibility in mandatory class I Federal areas which impairment results from manmade air pollution.”  <SU>3</SU> <FTREF/> Congress further directed the EPA to promulgate regulations to assure reasonable progress toward meeting this national goal. <SU>4</SU> <FTREF/> <FTNT> <SU>1</SU>  Clean Air Act section 169A. </FTNT> <FTNT> <SU>2</SU>  Areas statutorily designated as mandatory class I Federal areas consist of national parks exceeding 6,000 acres, wilderness areas and national memorial parks exceeding 5,000 acres, and all international parks that were in existence on August 7, 1977. Clean Air Act 162(a). There are 156 mandatory class I Federal areas. The list of areas to which the visibility protection program applies is set forth in 40 CFR part 81, subpart D. </FTNT> <FTNT> <SU>3</SU>  Clean Air Act section 169A(a)(1). </FTNT> <FTNT> <SU>4</SU>  Clean Air Act section 169A(a)(4). </FTNT> In 1990, Congress added section 169B to the Clean Air Act to further address visibility impairment, specifically, impairment from regional haze. The EPA subsequently promulgated the Regional Haze Rule on July 1, 1999 (64 FR 35714), codified at 40 CFR 51.308. <SU>5</SU> <FTREF/> These regional haze regulations are a central component of the EPA's comprehensive visibility protection program for Class I areas. <FTNT> <SU>5</SU>  In addition to the generally applicable regional haze provisions at 40 CFR 51.308, the EPA also promulgated regulations specific to addressing regional haze visibility impairment in Class I areas on the Colorado Plateau at 40 CFR 51.309. The latter regulations are applicable only for specific jurisdictions' regional haze plans submitted no later than December 17, 2007, and thus are not relevant here. </FTNT> Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities which are located across a broad geographic area and that emit pollutants that impair visibility. Visibility impairing pollutants include fine and coarse particulate matter (PM) ( <E T="03">e.g.,</E> sulfates, nitrates, organic carbon, elemental carbon, and soil dust) and their precursors ( <E T="03">e.g.,</E> sulfur dioxide (SO <E T="52">2</E> ), nitrogen oxides (NO <E T="52">X</E> ), and, in some cases, volatile organic compounds (VOC) and ammonia (NH <E T="52">3</E> )). Fine particle precursors react in the atmosphere to form fine particulate matter (PM <E T="52">2.5</E> ), which impairs visibility by scattering and absorbing light. Visibility impairment reduces the perception of clarity and color, as well as visible distance. <SU>6</SU> <FTREF/> <FTNT> <SU>6</SU>  There are several ways to measure the amount of visibility impairment, <E T="03">i.e.,</E> haze. One such measurement is the deciview, which is the principal metric used by the Regional Haze Rule. Under many circumstances, a change in one deciview will be perceived by the human eye to be the same on both clear and hazy days. The deciview is unitless. It is proportional to the logarithm of the atmospheric extinction of light, which is the perceived dimming of light due to its being scattered and absorbed as it passes through the atmosphere. Atmospheric light extinction (b <SU>ext</SU> ) is a metric used to for expressing visibility and is measured in inverse megameters (Mm <E T="51">−1</E> ). </FTNT> To address regional haze visibility impairment, the 1999 Regional Haze Rule established an iterative planning process that requires both States in which Class I areas are located and States “the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility” in a Class I area to periodically submit SIP revisions to address such impairment. <SU>7</SU> <FTREF/> Under the Clean Air Act, each SIP revision must contain “a long-term (ten to fifteen years) strategy for making reasonable progress toward meeting the national goal”. <SU>8</SU> <FTREF/> The initial round of SIP revisions also had to address the statutory requirement that certain older, larger sources of visibility impairing pollutants install and operate the best available retrofit technology (BART). <SU>9</SU> <FTREF/> States' first regional haze SIPs were due by December 17, 2007, <SU>10</SU> <FTREF/> with subsequent SIP revisions containing updated long-term strategies originally due July 31, 2018, and every ten years thereafter. <SU>11</SU> <FTREF/> The EPA established in the 1999 Regional Haze Rule that all States either have Class I areas within their borders or “contain sources whose emis ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 260k characters. 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