Air Plan Approval; Vermont; Regional Haze State Implementation Plan for the Second Implementation Period

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R01-OAR-2025-0142; FRL-12778-01-R1]</DEPDOC> <SUBJECT>Air Plan Approval; Vermont; Regional Haze State Implementation 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 Regional Haze State Implementation Plan (SIP) revision submitted by Vermont on July 1, 2024, as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule for the program's second implementation period. Vermont's SIP submission addresses the requirement that states must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to sections 110 and 169A of the Clean Air Act. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before June 23, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-0142 at <E T="03">https://www.regulations.gov,</E> or via email to <E T="03">martinelli.ayla@epa.gov.</E> For comments submitted at <E T="03">Regulations.gov</E> , follow the online instructions for submitting comments. Once submitted, comments cannot 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 (CBI) or other information whose disclosure 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 CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">https://www.epa.gov/dockets/commenting-epa-dockets.</E> Publicly available docket materials are available at <E T="03">https://www.regulations.gov</E> or at the U.S. Environmental Protection Agency, EPA Region 1 Regional Office, Air and Radiation Division, 5 Post Office Square—Suite 100, Boston, MA. EPA requests that if at all possible, you contact the contact listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section to schedule your inspection. The Regional Office's official hours of business are Monday through Friday, 8:30 a.m. to 4:30 p.m., excluding legal holidays and facility closures due to COVID-19. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Ayla Martinelli, Air Quality Branch, U.S. Environmental Protection Agency, EPA Region 1, 5 Post Office Square—Suite 100, (Mail code 5-MI), Boston, MA 02109-3912, tel. (617) 918-1057, email <E T="03">martinelli.ayla@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. What action is the EPA proposing?</FP> <FP SOURCE="FP-2">II. 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">III. Requirements for Regional Haze Plans for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Long-Term Strategy for Regional Haze</FP> <FP SOURCE="FP1-2">B. Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">C. Monitoring Strategy and Other State Implementation Plan Requirements</FP> <FP SOURCE="FP1-2">D. Requirements for Periodic Reports Describing Progress Towards the Reasonable Progress Goals</FP> <FP SOURCE="FP1-2">E. Requirements for State and Federal Land Manager Coordination</FP> <FP SOURCE="FP-2">IV. The EPA's Evaluation of Vermont's Regional Haze Submission for the Second Implementation Period</FP> <FP SOURCE="FP1-2">A. Background on Vermont's First Implementation Period SIP Submission</FP> <FP SOURCE="FP1-2">B. Vermont's Second Implementation Period SIP Submission 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">a. Vermont's Response to the Six MANEVU Asks</FP> <FP SOURCE="FP1-2">b. The EPA's Evaluation of Vermont's Response to the Six MANEVU Asks and Compliance With Section 51.308(f)(2)(i)</FP> <FP SOURCE="FP1-2">c. Additional Long-Term Strategy Requirements</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="FP1-2">J. Other Required Commitments</FP> <FP SOURCE="FP-2">V. Proposed Action</FP> <FP SOURCE="FP-2">VI. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. What action is the EPA proposing?</HD> On July 1, 2024, the Vermont Department of Environmental Conservation (VT DEC) submitted a revision to its SIP to address regional haze for the second implementation period. VT DEC made this SIP submission to satisfy the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. The EPA is proposing to find that the Vermont regional haze SIP submission for the second implementation period meets the applicable statutory and regulatory requirements and thus proposes to approve Vermont's submission into its SIP. <HD SOURCE="HD1">II. Background and Requirements for Regional Haze Plans</HD> A detailed history and background of the regional haze program is provided in multiple prior EPA proposal actions. <SU>1</SU> <FTREF/> For additional background on the 2017 RHR revisions, please refer to Section III. Overview of Visibility Protection Statutory Authority, Regulation, and Implementation of “Protection of Visibility: Amendments to Requirements for State Plans” of the 2017 RHR. <SU>2</SU> <FTREF/> The following is an abbreviated history and background of the regional haze program and 2017 Regional Haze Rule as it applies to the current action. <FTNT> <SU>1</SU>   <E T="03">See</E> 90 FR 13516 (March 24, 2025). </FTNT> <FTNT> <SU>2</SU>   <E T="03">See</E> 82 FR 3078 (January 10, 2017). </FTNT> <HD SOURCE="HD2">A. Regional Haze Background</HD> In the 1977 CAA Amendments, Congress created a program for protecting visibility in the nation's mandatory Class I Federal areas, which include certain national parks and wilderness areas. <SU>3</SU> <FTREF/> CAA 169A. The CAA establishes 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.” CAA 169A(a)(1). 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 (NH3)). 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>4</SU> <FTREF/> <FTNT> <SU>3</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. CAA 162(a). There are 156 mandatory Class I areas. The list of areas to which the requirements of the visibility protection program apply is in 40 CFR part 81, subpart D. </FTNT> <FTNT> <SU>4</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 RHR. 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> ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 148k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━