Air Plan Approval; Colorado; 2017 Base Year Inventory and Emission Statement Rule Marginal Nonattainment Requirements, Revisions to Regulation 3

ENVIRONMENTAL PROTECTION AGENCY <CFR>40 CFR Part 52</CFR> <DEPDOC>[EPA-R08-OAR-2023-0441; FRL-11837-01-R8]</DEPDOC> <SUBJECT>Air Plan Approval; Colorado; 2017 Base Year Inventory and Emission Statement Rule Marginal Nonattainment Requirements, Revisions to Regulation 3</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 state implementation plan (SIP) revisions submitted by the State of Colorado to meet certain Clean Air Act (CAA) requirements related to the Denver Metro/North Front Range (DMNFR) area's classification as Marginal nonattainment for the 2015 8-hour ozone national ambient air quality standards (NAAQS). The revisions contain a base year emissions inventory for the nonattainment area and certify that the State's existing Air Pollutant Emissions Notice (APEN) program fulfills the CAA's emission statement rule requirement. The revisions also include a new requirement for annual certification of APEN reported emissions. Unrelated to Colorado's Marginal ozone nonattainment obligations, EPA is also proposing to approve the State's revisions to Regulation 3 concerning an update to the date of incorporation by reference of global warming potentials used in the computation of the carbon dioxide equivalent for comparing emissions from various greenhouse gases (GHGs). EPA is taking this action pursuant to the CAA. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> Written comments must be received on or before May 10, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> Submit your comments, identified by Docket ID No. EPA-R08-OAR-2023-0441, to the Federal Rulemaking Portal: <E T="03">https://www.regulations.gov.</E> Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from <E T="03">www.regulations.gov.</E> 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, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit <E T="03">http://www2.epa.gov/dockets/commenting-epa-dockets.</E> <E T="03">Docket:</E> All documents in the docket are listed in the <E T="03">www.regulations.gov</E> index. Although listed in the index, some information is not publicly available, <E T="03">e.g.,</E> 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 electronically in <E T="03">www.regulations.gov.</E> To reduce the risk of COVID-19 transmission, for this action we do not plan to offer hard copy review of the docket. Please email or call the person listed in the <E T="02">FOR FURTHER INFORMATION CONTACT</E> section if you need to make alternative arrangements for access to the docket. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Matthew Lang, Air and Radiation Division, EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6709, <E T="03">lang.matthew@epa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> Throughout this document wherever “we,” “us,” or “our” is used, we mean the EPA. <HD SOURCE="HD1">Table of Contents</HD> <EXTRACT> <FP SOURCE="FP-2">I. Background</FP> <FP SOURCE="FP-2">II. The EPA's Evaluation of Colorado's SIP Submittals</FP> <FP SOURCE="FP1-2">A. Base Year Emissions Inventory</FP> <FP SOURCE="FP1-2">1. Point Source Emissions</FP> <FP SOURCE="FP1-2">2. Nonpoint Source Emissions</FP> <FP SOURCE="FP1-2">3. On-Road Mobile Source Emissions</FP> <FP SOURCE="FP1-2">4. Nonroad Mobile Source Emissions</FP> <FP SOURCE="FP1-2">5. Oil and Gas Emissions</FP> <FP SOURCE="FP1-2">6. Biogenic Emissions</FP> <FP SOURCE="FP1-2">7. EPA's Evaluation of the Base Year Emissions Inventory</FP> <FP SOURCE="FP1-2">B. Certification of Existing Emission Statement Rule and Addition of Annual Certification Requirement</FP> <FP SOURCE="FP1-2">C. Other Revisions to Regulation 3, Part A</FP> <FP SOURCE="FP1-2">1. Regulation 3, Part A, Sections I.B.10 and 1.B.44.b.(i)—Date of Incorporation by Reference of Global Warming Potentials</FP> <FP SOURCE="FP1-2">2. Regulation 3, Part A, Section I.B.44.(b).(i)—Computation of Mass of Carbon Dioxide Equivalent</FP> <FP SOURCE="FP-2">III. Proposed Action</FP> <FP SOURCE="FP-2">IV. Incorporation by Reference</FP> <FP SOURCE="FP-2">V. Statutory and Executive Order Reviews</FP> </EXTRACT> <HD SOURCE="HD1">I. Background</HD> EPA determined decades ago that ground-level ozone endangers public health and welfare. Ground-level ozone forms when nitrogen oxides (NO <E T="52">X</E> ) and volatile organic compounds (VOC) react in the presence of sunlight. Referred to as ozone precursors, these two pollutants are emitted by many types of pollution sources, including motor vehicles, power plants, industrial facilities, and nonpoint  <SU>1</SU> <FTREF/> sources. Scientific evidence indicates that adverse human health effects occur following exposure to ozone. These effects are more pronounced in children and adults with lung disease. Breathing air containing ozone can reduce lung function and inflame airways, which can increase respiratory symptoms and aggravate asthma or other lung diseases. In 1979, in response to this scientific evidence, EPA promulgated the first ozone NAAQS, the 0.12 parts per million (ppm) 1-hour ozone NAAQS. <SU>2</SU> <FTREF/> <FTNT> <SU>1</SU>  Nonpoint sources are also sometimes referred to as area sources. </FTNT> <FTNT> <SU>2</SU>  44 FR 8202 (Feb. 8, 1979). </FTNT> EPA has strengthened the ozone NAAQS over the years. In 1997, EPA promulgated a revised ozone NAAQS of 0.08 ppm, averaged over eight hours, which it determined was more protective of public health than the 1979 standard. <SU>3</SU> <FTREF/> In 2008, EPA revised the 8-hour ozone NAAQS from 0.08 to 0.075 ppm. <SU>4</SU> <FTREF/> In 2015, the Agency further strengthened the 8-hour ozone NAAQS to 0.070 ppm. <SU>5</SU> <FTREF/> <FTNT> <SU>3</SU>  62 FR 38856 (July 18, 1997). </FTNT> <FTNT> <SU>4</SU>  73 FR 16436 (Mar. 27, 2008). </FTNT> <FTNT> <SU>5</SU>  80 FR 65292 (Oct. 26, 2015). </FTNT> The DMNFR area is in nonattainment status for both the 2008 and the 2015 ozone NAAQS. It is currently classified as a Severe nonattainment area under the 2008 standard, <SU>6</SU> <FTREF/> which is not at issue in this rulemaking. Effective August 3, 2018, EPA designated the DMNFR area as Marginal nonattainment for the more stringent 2015 ozone NAAQS (2015 DMNFR Nonattainment Area). <SU>7</SU> <FTREF/> The 2015 DMNFR Nonattainment Area includes Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, and Weld counties as well as a portion of Larimer County. <SU>8</SU> <FTREF/> While EPA has since reclassified the 2015 DMNFR Nonattainment Area as Moderate for failing to attain the 2015 ozone NAAQS by the area's Marginal attainment date, <SU>9</SU> <FTREF/> Colorado must still meet the CAA requirements applicable to Marginal ozone nonattainment areas. <FTNT> <SU>6</SU>  40 CFR 81.306; 87 FR 60926, 60933 (Oct. 7, 2022). </FTNT> <FTNT> <SU>7</SU>  83 FR 25776, 25792 (June 4, 2018). </FTNT> <FTNT> <SU>8</SU>  As detailed in this proposed rule, EPA initially excluded part of Weld County from the 2015 DMNFR Nonattainment Area, but, in response to a court decision, subsequently expanded its air quality designation to include all of Weld County. </FTNT> <FTNT> <SU>9</SU>  40 CFR 81.306; 87 FR 60897, 60916 (Oct. 7, 2022). </FTNT> This proposed rule addresses only the base year inventory and emission statement rule requirements related to the Marginal nonattainment classification, as described further below, including SIP revisions to address EPA's revised designation incorporating all of Weld County into the nonattainment area. <SU>10</SU> <FTREF/> Requirements stemming from the DMNFR Nonattainment Area's Moderate nonattainment classification for the 2015 ozone NAAQS and the Severe classification for the 2008 ozone NAAQS will be addressed in separate EPA rulemakings. <FTNT> <SU>10</SU>   <E T="03">See</E> 86 FR 67864, 67869 (Nov. 30, 2021) (noting that states affected by the revised air quality designations would “work with their respective EPA Regional office to submit any necessary supplements or revisions to fulfill the Marginal area SIP revision requirements associated with the nonattainment boundaries in this final action as expeditiously as practicable”). </FTNT> The CAA and its implementing regulations—in particular, the 2015 ozone NAAQS SIP Requirements Rule, <SU>11</SU> <FTREF/> codified at 40 CFR part 51, subpart CC—establish several requirements for ozone nonattainment areas. Section 172(c)(3) of the CAA, which applies generally to states with areas classified as nonattainment for any NAAQS, requires submission of comprehensive, accurate, and current inventories of actual emissions from all sources of relevant pollutants in Marginal nonattainment areas. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 56k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━