90 FR 65 pgs. 14935-14939 - Air Plan Approval; Connecticut; 2017 Base Year Emissions Inventory for the 2015 8-Hour Ozone National Ambient Air Quality Standards
Type: PRORULEVolume: 90Number: 65Pages: 14935 - 14939
Pages: 14935, 14936, 14937, 14938, 14939Docket number: [EPA-R01-OAR-2025-0076; FRL-12691-01-R1]
FR document: [FR Doc. 2025-05910 Filed 4-4-25; 8:45 am]
Agency: Environmental Protection Agency
Official PDF Version: PDF Version
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R01-OAR-2025-0076; FRL-12691-01-R1]
Air Plan Approval; Connecticut; 2017 Base Year Emissions Inventory for the 2015 8-Hour Ozone National Ambient Air Quality Standards
AGENCY:
Environmental Protection Agency (EPA).
ACTION:
Proposed rule.
SUMMARY:
The Environmental Protection Agency (EPA) is proposing approval of State Implementation Plan (SIP) revisions submitted by the State of Connecticut that relate to the 2015 Ozone National Ambient Air Quality Standards (NAAQS). The SIP revisions are for the Greater Connecticut and the Connecticut portion of the New York-Northern New Jersey-Long Island, NY-NJ-CT ozone nonattainment areas. The intended effect of this action is to propose approval of submittals which include a 2017 base year emissions inventory for the 2015 Ozone National Ambient Air Quality Standard. This action is being taken under the Clean Air Act.
DATES:
Written comments must be received on or before May 7, 2025.
ADDRESSES:
[top] Submit your comments, identified by Docket ID No. EPA-R01-OAR-2025-0076 at https://www.regulations.gov, or via email to lillis.patrick@epa.gov. Or comments submitted at Regulations.gov , follow the online instructions for submitting comments. Once submitted, comments cannot be edited or removed from Regulations.gov . 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 ( i.e., on the web, cloud, or other file sharing system). For additional submission methods, please contact the person identified in the FOR FURTHER INFORMATION CONTACT section. For the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. Publicly available docket materials are available at https://www.regulations.gov or at the U.S. Environmental Protection Agency,
FOR FURTHER INFORMATION CONTACT:
Patrick Lillis, Air and Radiation Division (Mail Code 5-MI), U.S. Environmental Protection Agency-Region 1, 5 Post Office Square, Suite 100, Boston, Massachusetts 02109-3912; tel. (617) 918-1067, or by email at lillis.patrick@epa.gov.
SUPPLEMENTARY INFORMATION:
Throughout this document whenever "we," "us," or "our" is used, we mean EPA.
Table of Contents
I. Background and Purpose
II. Description of State's Submittals
III. The EPA's Evaluation of Connecticut's SIP Submittals
A. 2017 Base Year Emissions Inventory
1. Point Source Emissions
2. Nonpoint Source Emissions
3. On-Road Mobile Source Emissions
4. Non-Road Source Emissions
5. Biogenic Emissions
6. EPA's Evaluation of the Base Year Emissions Inventory
IV. Proposed Action
V. Statutory and Executive Order Reviews
I. Background and Purpose
Ozone is one of the six common air pollutants identified in the Clean Air Act. Ground-level ozone forms when nitrogen oxides (NO X ) 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? 1 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. 2
Footnotes:
1 ??Nonpoint sources are also sometimes referred to as area sources.
2 ?See 44 FR 8202 (Feb. 8, 1979).
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. 3 In 2008, EPA revised the 8-hour ozone NAAQS from 0.08 to 0.075 ppm. 4 In 2015, the Agency further strengthened the 8-hour ozone NAAQS to 0.070 ppm. 5
Footnotes:
3 ?See 62 FR 38856 (July 18, 1997).
4 ?See 73 FR 16436 (Mar. 27, 2008).
5 ?See 80 FR 65292 (Oct. 26, 2015).
Effective August 3, 2018, the EPA designated as nonattainment any area that was violating the 2015 8-hour ozone NAAQS based on the three most recent years (2014-2016) of air monitoring data. 6 With that rulemaking, the Connecticut portion of the New York-Northern New Jersey-Long Island NY-NJ-CT area was originally designated as a moderate ozone nonattainment area. This area is herein referred to as the Connecticut portion of the NY-NJ-CT area. Additionally, in that rulemaking, the Greater Connecticut area was originally designated as a Marginal ozone nonattainment area. Effective November 7, 2022, the EPA reclassified the Greater Connecticut area under the CAA from "Marginal" to "Moderate" for the 2015 8-hour ozone NAAQS. 7 Areas that were designated as moderate nonattainment were required to attain the 2015 8-hour ozone NAAQS no later than August 3, 2024, based on 2021-2023 monitoring data. Effective July 25, 2024, the EPA published a final rule granting a voluntary reclassification request to redesignate the Connecticut portion of the NY-NJ-CT area to Serious nonattainment for the 2015 8-hour ozone NAAQS. 8 And effective July 29, 2024, EPA published a final rule granting a voluntary reclassification request to redesignate the Greater Connecticut area to Serious nonattainment for the 2015 8-hour ozone NAAQS. 9 Serious areas are required to attain the 2015 8-hour ozone NAAQS as expeditiously as practicable, but no later than nine years from the date of the initial designation as nonattainment, i.e., by August 3, 2027. 10 While EPA has since reclassified both nonattainment areas in Connecticut to Serious for the 2015 8-hour ozone NAAQS, Connecticut must still meet the CAA requirements applicable to Marginal ozone nonattainment areas.
Footnotes:
6 ?See 83 FR 25776, 25792 (June 4, 2018).
7 ?See 87 FR 60897 (October 7, 2022).
8 ?See 89 FR 60314 (July 25, 2024).
9 ?See 89 FR 60827 (July 29, 2024).
10 ?See 40 CFR 51.1303
This proposed rule addresses only the base year inventory requirements related to the Marginal nonattainment classification. The CAA and its implementing regulations-in particular, the 2015 ozone NAAQS SIP Requirements Rule, 11 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. 12 Specific to areas classified as Marginal ozone nonattainment, section 182(a)(1) requires states to submit a base year inventory of ozone precursors (NO X and VOC).
Footnotes:
11 ??See 83 FR 62998 (Dec. 6, 2018). The SIP Requirements Rule established implementation requirements for the 2015 ozone NAAQS, including requirements for base year emissions inventories.
12 ?See 42 U.S.C. 7502(c)(3).
Emissions inventories provide data that inform a variety of air quality planning tasks. States use emissions inventories to establish baseline emissions levels, calculate emissions reduction targets needed to attain the NAAQS, determine emissions inputs for ozone air quality modeling analyses, and track emissions over time to determine progress toward achieving air quality and emissions reduction goals. EPA has issued guidance to assist states in developing their emission inventories; states retain the discretion to adopt approaches on a case-by-case basis that differ from that guidance where appropriate. 13
Footnotes:
13 ?U.S. EPA, "Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations," EPA-454/B-17-002 at 1 (May 2017) (hereinafter, "2017 Emissions Inventory Guidance").
II. Description of State's Submittals
On May 3, 2024, Connecticut Department of Energy and Environmental Protection (CT DEEP) submitted a 2017 base year emissions inventory of ozone precursors for all areas of the State. A copy of the 2017 base year inventory is located in the docket of this proposed rulemaking.
III. The EPA's Evaluation of Connecticut's SIP Submittals
A. 2017 Base Year Emissions Inventory
[top] Under CAA sections 172(c)(3) and 182(a)(1), Connecticut must submit a comprehensive, accurate, and current accounting of actual emissions of ozone precursors from all sources (point,
Footnotes:
14 ?See 40 CFR 51.1315(a).
15 ?See 83 FR 62998, 63005.
16 ?See 40 CFR 51.1315(c).
17 ?See 40 CFR 51.1300(q).
18 ?See 2017 Emissions Inventory Guidance, 75.
On May 3, 2024, Connecticut submitted to EPA as a SIP revision request an emissions inventory of ozone precursors for 2017. The inventory was submitted to meet the CAA section 182(a)(3)(A) obligation to develop a base year inventory. The State conducted a public comment process on the inventory which concluded on January 26, 2024. The inventories include emission estimates in tons per summer day and represent emissions estimates from stationary and mobile source categories during a typical summer day when ozone formation is highest. The ozone emissions inventory catalogs NO X and VOC emissions because these pollutants are precursors to ozone formation. Connecticut's 2017 emissions inventory contains emission estimates at the county level and summed to the geographic areas that correspond to the State's two Serious ozone nonattainment areas.
We propose to find that the air emission estimates for these sources were adequately accounted for in Connecticut's 2017 base year emissions inventory. The methodology used to calculate emissions for each source category followed relevant EPA guidance, most notably the May 2017 guidance entitled "Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter National Ambient Air Quality Standards and Regional Haze Regulations,"? 19 used appropriate, documented emission factors, or relied on emission estimates prepared for EPA's National Emissions Inventory. Furthermore, the inventory submittal is sufficiently documented as to the techniques used to prepare the emission estimates.
Footnotes:
19 ?See 2017 Emissions Inventory Guidance.
Table 1 shows the emissions by source category, in tons per summer day (tpsd), from the 2017 base year emission inventory for each of the State's two nonattainment areas.
Footnotes:
20 ?See CT DEEP's 2017 Emission Inventory Submittal, 1-15.
| Source | CT portion of NY-NJ-CT area | VOC | NO X | Greater CT area | VOC | NO X |
|---|---|---|---|---|---|---|
| Point | 3.6 | 14.0 | 1.1 | 10.2 | ||
| Nonpoint | 52.7 | 6.9 | 53.0 | 6.0 | ||
| Onroad | 20.0 | 25.5 | 18.1 | 22.2 | ||
| Nonroad | 16.6 | 19.0 | 13.5 | 15.4 | ||
| Biogenic | 168.3 | 0.8 | 308.8 | 1.7 | ||
| Totals | 261.3 | 66.2 | 394.5 | 55.6 |
1. Point Source Emissions
Point sources are large, stationary, identifiable sources of emissions that release pollutants into the atmosphere. The SIP Requirements Rule provides that emissions from point sources shall be reported according to the thresholds of EPA's Air Emissions Reporting Requirements (AERR). 21 The 2017 Emissions Inventory Guidance directs those preparing point source inventories to volume 2 of the Emissions Inventory Improvement Program technical report series for information on point source inventory methodology. 22 This resource describes the three principal methods for estimating point source emissions as source testing, mass balance calculations, and emission factors, with a fourth method utilizing engineering calculations if the principal methods are not possible. 23
Footnotes:
21 ?See?40 CFR 51.1315(d).
22 ?See 2017 Emissions Inventory Guidance, 81-82.
23 ??U.S. EPA, EIIP Technical Report Series Vol. II, Ch. 1: "Introduction to Stationary Point Source Emission Inventory Development" (May 2001), 1.4-1-1.4-3.
Since 2009, Connecticut requires all Title V sources that have a Title V permit or that have been specifically requested to file by CT DEEP to submit an emissions statement. Beginning in 2014, companies were required to submit their emissions statements electronically via CT DEEP's software application, EMIT. Ozone precursor emissions are collected using EMIT. The 2017 stationary source inventory is primarily based on the emissions statement submittals, which reported the source's actual 2017 emissions signed by a corporate officer who attested to the accuracy of their calculations. Facility data for the eighty-three (83) Connecticut sites are recorded in Section 2.1 of CT DEEP's 2017 emissions inventory submittal that is located in the docket of this proposed rulemaking. Since Connecticut's base year inventory is consistent with the reporting thresholds in the AERR and uses methods for estimating emissions recommended by EPA guidance, 24 the base year inventory adequately addresses emissions from the point source category.
Footnotes:
24 ?See CT DEEP's 2017 Emission Inventory Submittal, 2-5.
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2. Nonpoint Source Emissions
Nonpoint or area source emission estimates are made for small, stationary sources of air pollution that do not emit much individually, but do have significant emissions collectively. Examples include gasoline stations, residential heating, and fuel combustion. Connecticut's area source emissions inventory identifies the source categories for which the State relied upon EPA's estimates, provides information on any adjustments made to EPA estimates, and notes which categories' emission estimates were prepared by the State. The inventory also explains how double counting between emissions from facilities inventoried as individual point sources were excluded from the area source emission estimates. 25 Therefore, the base year inventory adequately addresses emissions from the nonpoint source category.
Footnotes:
25 ?See CT DEEP's 2017 Emission Inventory Submittal, Section 4.
3. On-Road Mobile Source Emissions
On-road mobile sources are motor vehicles ( e.g. automobiles, buses, and trucks) that travel on local roads and highways. A motor vehicle is defined in 40 CFR 51.50? 26 as "any self-propelled vehicle used to carry people or property on a street or highway". Emissions from on-road vehicles are the result of several processes, including the combustion of fuel while vehicles are starting, idling, or moving; the evaporation of fuel from the fuel system and during refueling; as well as from the wearing of brakes and tires.
Footnotes:
26 ?See 40 CFR 51.50
To estimate on-road emissions in 2017, CT DEEP ran EPA's model MOVES2014b for all eight Connecticut counties in inventory-mode using established annual and summer day input data. EPA's Motor Vehicle Emission Simulator (MOVES) is a state-of-the-science emission modeling system that estimates emissions for mobile sources at the national, county, and project level for criteria air pollutants, greenhouse gases, and air toxics. Vehicles are classified in MOVES according to thirteen source types and five Highway Performance Monitoring System (HPMS) vehicle types. Part 3.1.1 of CT DEEP's 2017 emission inventory submittal provides an explanation and the basis for the input parameters used in MOVES2014b for the calculation and development of this emissions inventory. CT DEEP's 2017 emission inventory is located in the docket of this proposed rulemaking.
Connecticut's on-road mobile source emissions inventory methodology follows the SIP Requirements Rule? 27 as well as EPA's 2017 Emissions Inventory Guidance. 28 Therefore, the base year inventory adequately addresses emissions from the on-road mobile source category.
Footnotes:
27 ?See 83 FR 62998.
28 ?See 2017 Emissions Inventory Guidance, 89-90.
4. Non-Road Source Emissions
Non-road mobile sources are comprised of non-road engines and non-road vehicles, which are respectively defined in 40 CFR 51.50? 29 as "an internal combustion engine (including fuel system) that is not used in a motor vehicle or a vehicle used solely for competition, or that is not affected by sections 111 or 202 of the Clean Air Act"? 30 and "a vehicle that is run by a non-road engine and that is not a motor vehicle or a vehicle used solely for competition."? 31 These sources include vehicles, engines, and equipment used for construction, agriculture, recreation, and many other purposes. The equipment must either move under its own power or be capable of being moved from site to site. Emissions from non-road vehicles come from both exhaust and non-exhaust processes, including the combustion of fuel while vehicles are starting, idling, or moving, as well as from the evaporation of fuel from the fuel system and during refueling.
Footnotes:
29 ?See 40 CFR 51.50.
30 ?See CAA Section 111 and 202.
31 ?See 40 CFR 51.50.
To estimate non-road emissions in 2017, CT DEEP ran MOVES2014b for all eight Connecticut counties in inventory-mode using established annual and summer day input data. Connecticut's 2017 base year inventory used EPA's MOVES-Nonroad model to estimate emissions from nonroad mobile sources in the Connecticut portion of the NY-NJ-CT Nonattainment area as well as the Greater Connecticut Nonattainment Area, except for emissions from aviation, locomotives, and commercial marine vessels (CMV). Connecticut adopted EPA's 2017 NEI estimates for aviation, locomotive, and CMV emissions. See section 3.3 through 3.5 in CT's 2017 emission inventory for more information on aviation, locomotives, and CMV emission calculations. CT DEEP's 2017 emission inventory is located in the docket of this proposed rulemaking. Therefore, the base year inventory adequately addresses emissions from the non-road mobile source category.
5. Biogenic Emissions
Biogenic emissions come from natural sources. Connecticut included a 2017 inventory of biogenic emissions separate from the anthropogenic portion of the inventory. Connecticut accepted the EPA biogenic emissions estimates as published in the 2017 NEI. For more information on these estimates, please refer to Section 4.6 of the 2017 NEI v1 TSD. 32 The annual estimates for this sector in 2017 are presented in Section 5 of Connecticut's 2017 emission inventory submittal. CT DEEP's 2017 emission inventory is located in the docket of this proposed rulemaking. Therefore, the base year inventory adequately addresses emissions from the biogenic source category.
Footnotes:
32 ?See Section 4.6 of the 2017 NEI v1 TSD.
6. EPA's Evaluation of the Base Year Emissions Inventory
Based on EPA's review and evaluation of the methodologies, procedures, and results in Connecticut's 2017 base year emissions inventory, we propose to find that the inventory meets the requirements of CAA sections 172(c)(3) and 182(a)(1) and the SIP Requirements Rule. The base year inventory is based on the most current and accurate information that was available to the State at the time the inventory was developed. Additionally, the 2017 inventory comprehensively addresses all source categories in the Connecticut portion of the NY-NJ-CT Nonattainment Area, as well as the Greater Connecticut Nonattainment Area and was developed consistent with the relevant EPA emissions inventory regulations, guidance, and models.
IV. Proposed Action
EPA is proposing to approve SIP submittals from the state of Connecticut for the 2017 base year emissions inventory for the 2015 8-hour ozone NAAQS for both the Greater Connecticut and the Connecticut portion of the NY-NJ-CT nonattainment areas. EPA is soliciting public comment on the issues discussed in this document or on other relevant matters. These comments will be considered before taking final action. Interested parties may participate in the Federal rulemaking procedure by submitting written comments to this proposed rule by following the instructions listed in the ADDRESSES section of this Federal Register .
V. Statutory and Executive Order Reviews
[top] Under the Clean Air Act, the Administrator is required to approve a
• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders 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 subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;
• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and
• 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 Clean Air Act.
In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by reference, Nitrogen dioxide, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds.
Dated: March 20, 2025.
Karen McGuire,
Acting Regional Administrator, EPA Region 1.
[FR Doc. 2025-05910 Filed 4-4-25; 8:45 am]
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