Environmental Protection Agency (EPA).
Proposed rule.
The Environmental Protection Agency (EPA) is proposing to approve as a State Implementation Plan (SIP) revision the Morgan County-related elements of an Indiana submission to EPA dated October 2, 2015, as supplemented on February 8, 2019. The October 2015 submission addresses attainment of the 2010 sulfur dioxide (SO
Comments must be received on or before August 8, 2019.
Submit your comments, identified by Docket ID No. EPA–R05–OAR–2015–0700 at
John Summerhays, Environmental Scientist, Attainment Planning and Maintenance Section, Air Programs Branch (AR–18J), Environmental Protection Agency, Region 5, 77 West Jackson Boulevard, Chicago, Illinois 60604, (312) 886–6067,
The following outline is provided to aid in locating information in this preamble.
On June 22, 2010, EPA promulgated a new 1-hour primary SO
In response to the requirement for SO
In addition to its submittal, Indiana sent multiple supplemental letters addressing the Morgan County SO
Nonattainment SIPs must meet the applicable requirements of the Clean Air Act, specifically Clean Air Act sections 110, 172, 191 and 192. EPA's regulations governing nonattainment SIPs are set forth at 40 CFR part 51, with specific procedural requirements and control strategy requirements residing at subparts F and G, respectively. Soon after Congress enacted the 1990 Amendments to the Clean Air Act, EPA issued comprehensive guidance on SIPs, in a document entitled the “General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990,” published at 57 FR 13498 (April 16, 1992) (General Preamble). Among other things, the General Preamble addressed SO
In order for EPA to fully approve a SIP as meeting the requirements of Clean Air Act sections 110, 172 and 191–192 and EPA's regulations at 40 CFR part 51, the SIP for the affected area needs to demonstrate to EPA's satisfaction that each of the aforementioned requirements have been met. Under Clean Air Act sections 110(l) and 193, EPA may not approve a SIP that would interfere with any applicable requirement concerning NAAQS attainment and RFP, or any other applicable requirement, and no requirement in effect (or required to be adopted by an order, settlement, agreement, or plan in effect before November 15, 1990) in any area which is a nonattainment area for any air pollutant, may be modified in any manner unless it ensures equivalent or
Clean Air Act sections 172(c)(1), 172(c)(6) and 192(a) direct states with SO
EPA's April 2014 guidance recommends that the emission limits be expressed as short-term average limits (
Preferred air quality models for use in regulatory applications are described in appendix A of EPA's Guideline on Air Quality Models.
As stated previously, attainment demonstrations for the 2010 SO
The meteorological data used in the analysis should generally be processed with the most recent version of AERMET. Estimated concentrations should include ambient background concentrations, should follow the form of the standard, and should be calculated as described in section 2.6.1.2 of the August 23, 2010 clarification memo on “Applicability of Appendix W Modeling Guidance for the 1-hr SO
The following discussion evaluates various features of the modeling that Indiana used in its attainment demonstration for Morgan County.
Indiana's attainment demonstrations used AERMOD, the preferred model for these applications as identified in the Guideline on Air Quality Models. Indiana's October 2015 submittal used version 14134 of this model, which was the most recent version at the time the state conducted its nonattainment planning. However, the supplemental modeling that Indiana submitted in February 2019 used the current version of AERMOD, version 18081. Indiana utilized the regulatory default mode for all air quality modeling runs.
Indiana's receptor grid and modeling domain for the Morgan County area generally followed the recommended approaches from the Guideline on Air Quality Models. Receptor spacing for each modeled facility fence line was every 50 meters, then 100-meter spacing of receptors out to a distance of 0.5 kilometers, every 250 meters out to 2.5 kilometers, every 500 meters out to 5 kilometers, and every 1000 meters out to 10 kilometers from each facility. The resulting receptor grid contained 10,445 receptors. An examination of the modest modeled spatial gradients near the facility boundaries leads to the conclusion that no facility in the area contributes to violations within any other facility's property, so that the exclusion of receptors within facility fencelines was acceptable.
Indiana determined that Morgan County should be modeled with rural dispersion characteristics. Indiana did not provide an Auer analysis or provide other rationale for this selection. Nevertheless, the nonattainment area, consisting of two townships (Clay and Washington Townships) have a 2016 estimated population of 21,379 people in an area of 232.3 square kilometers, an average population density of 92 people per square kilometer. By comparison, the Guideline on Air Quality Models suggests that areas with less than 750 people per square kilometer warrant being modeled with rural dispersion characteristics. Therefore, EPA concurs with Indiana's determination that this
Indiana used the Indianapolis National Weather Service (NWS) surface data and the Lincoln, Illinois upper air station (WBAN 048233) data for modeling Morgan County. EPA finds these selections appropriate.
Indiana identified two sources in Morgan County emitting over 100 tons per year. Indianapolis Power and Light's Eagle Valley power plant, which conducts continuous SO
An important prerequisite for approval of an attainment plan is that the emission limits that provide for attainment be quantifiable, fully enforceable, replicable, and accountable. See General Preamble at 13567–68.
In preparing its plans, Indiana adopted revisions to a previously approved state regulation governing emissions of SO
Given the requirement for Eagle Valley to burn natural gas, EPA finds the low emission rate that Indiana modeled for this plant to be an appropriate reflection of allowable emissions. Indiana did not explicitly model Hydraulic Press Brick, choosing instead to address this source as part of the background concentration. The adequacy of Indiana's background concentration to reflect the impact of this source and other unmodeled emissions in the area is addressed in the following section.
Indiana determined background concentrations for Morgan County using hourly measurements at the Centerton School monitor (site number 18–109–1001). In its original analysis, documented in its submittal of October 2, 2015, Indiana determined background concentrations for this area by selecting the 99th percentile of a monitoring data set that excluded values when the monitor was downwind of either the Eagle Valley plant or Hydraulic Press Brick, except that values below 10 ppb were retained in the analysis. The 99th percentile among the pertinent values was 9.4 ppb, or 24.6 micrograms per cubic meter (μg/m
The purpose of background concentrations in a model simulation is to represent the impact of emissions from sources that are not explicitly modeled. Indiana explicitly modeled the allowable emissions from Eagle Valley, and so Indiana's approach, determining background concentrations in a manner that excluded occasions with significant impacts from Eagle Valley, was appropriate for avoiding double counting the impacts of this source. However, Indiana did not explicitly model Hydraulic Press Brick, choosing instead to represent this source as part of the background concentration in the modeling. For this reason, EPA found it inappropriate that Indiana excluded occasions with impacts from Hydraulic Press Brick in its determination of a background concentration.
To address this concern, Indiana conducted additional analyses to identify background concentrations that would better represent the impacts of Hydraulic Press Brick and minor other SO
Examination of these data led to the finding that aside from occasions when Eagle Valley was upwind of the monitor, the highest concentrations were observed when winds were in a relatively narrow band of wind directions approximately centered on Hydraulic Press Brick being upwind of the monitor. Ordinarily background concentrations are determined by examining concentrations for almost all wind directions, excluding data for a modest set of directions when modeled sources are upwind. However, in this case Indiana followed the reverse approach, excluding occasions when Hydraulic Press Brick was not upwind of the monitor and considering concentrations only for a relatively small band of wind directions in which the largest unmodeled source (Hydraulic Press Brick) was most directly upwind. In particular, the data set used in this analysis included concentrations when the winds were from between 25 degrees and 60 degrees (roughly from NNE to ENE). This approach was designed to estimate the maximum background concentration that could be attributed to unmodeled sources in the area, including a conservative representation of the impacts of Hydraulic Press Brick.
EPA guidance offers both the option to determine a single background concentration, to be used for all seasons and all hours, and the option to determine separate season- and hour-specific background concentrations. Indiana applied both options in this case. The resulting single background concentration was 96.0 μg/m
Modeling for Morgan County in Indiana's October 2, 2015 submittal showed a design value of 35.9 μg/m
Pursuant to the requirements in Indiana's rules, Hydraulic Press Brick began sorbent injection, to achieve either 50 percent control or 2.5 lbs/MMBTU of SO
The emissions inventory and source emission rate data for an area serve as the foundation for air quality modeling and other analyses that enable states to: (1) Estimate the degree to which different sources within a nonattainment area contribute to violations within the affected area; and (2) assess the expected improvement in air quality within the nonattainment area due to the adoption and implementation of control measures. As noted above, the state must develop and submit to EPA a comprehensive, accurate and current inventory of actual emissions from all sources of SO
Indiana provided a comprehensive, accurate, and current inventory of SO
Indiana's emission inventory indicated that Eagle Valley in 2012 emitted 3,436 tons of SO
By providing a comprehensive, accurate, and current inventory of SO
In its submission, Indiana discusses its rationale for concluding that the nonattainment plans meet the RACM/RACT requirements in accordance with EPA guidance. For most criteria pollutants, RACT is control technology as needed to meet the NAAQS that is reasonably available considering technological and economic feasibility. However, Indiana cites EPA guidance that the definition of RACT for SO
In addition, Indiana has adopted and submitted limits that require effective control of the most significant sources in Morgan County. The requirement for Eagle Valley to burn natural gas brings the emissions of this source nearly to zero. The requirement for Hydraulic Press Brick to operate a sorbent injection system in a manner that generally achieves 50 percent emission control requires operating a control that is cost effective and achieves a relatively high degree of control for this type of source. Thus, while Indiana did not conduct a cost effectiveness analysis of these controls, and EPA does not require such an analysis, the controls required in this area appear to represent a full set of reasonably available emission control.
Indiana has determined that these measures suffice to provide for timely attainment. EPA concurs and proposes
As Indiana's submittal explains, EPA approved Indiana's nonattainment new source review rules on October 7, 1994 (94 FR 24838). As Indiana notes, these rules provide for appropriate new source review for SO
Indiana's adopted rules in 326 IAC 7 require that control measures be implemented no later than January 1, 2017. Indiana has concluded that this plan requires that affected sources implement appropriate control measures as expeditiously as practicable in order to ensure attainment of the standard by the applicable attainment date. Indiana concludes that this plan therefore provides for RFP in accordance with the approach to RFP described in EPA's guidance. EPA concurs and proposes to conclude that the plan provides for RFP.
Indiana's approach to contingency measures is one of the subjects of a clarification memo that Indiana submitted on November 15, 2017. In this memo, Indiana explained its rationale for concluding that its plans met the requirement for contingency measures in accordance with EPA guidance. Specifically, Indiana relies on EPA's guidance, noting the special circumstances that apply to SO
Indiana's rules also provide for additional contingency measures as necessary, following a review of any air quality problems that become identified and following a review of options for mitigating the problems that arise. However, Indiana is not relying on these provisions to satisfy the requirements for contingency measures.
EPA is proposing to approve Indiana's SIP submission, which the state submitted to EPA on October 2, 2015 and supplemented on November 15, 2017, June 7, 2017, February 8, 2019, and February 12, 2019, for attaining the 2010 1-hour SO
The rules that underpin Indiana's attainment plan for Morgan County include Indiana Administrative Code, Title 326, Rule 7–4–11.1 (326 IAC 7–4–11.1, entitled “Morgan County sulfur dioxide emission limitations”), as well as Rule 326 IAC 7–1.1–3 (entitled “Compliance date”) and Rule 326 IAC 7–2–1 (entitled “Reporting requirements; methods to determine compliance”). EPA has already approved the latter two rules, as part of its rulemaking on the plans for Marion and Vigo Counties. These rules provide compliance dates and recordkeeping and compliance determination provisions that apply to all four areas in Indiana's original submittal. Because these latter two rules are already part of the Indiana SIP, and no further action on these rules is necessary, EPA is proposing only to approve 326 IAC 7–4–11.1.
EPA is taking public comments for thirty days following the publication of this proposed action in the
In this rule, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference 326 IAC 7–4–11.1, “Morgan County sulfur dioxide emission limitations”, effective at the state on October 2, 2015. EPA has made, and will continue to make, these documents generally available through
Under the Clean Air Act, 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 Clean Air Act. 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) and 13563 (76 FR 3821, January 21, 2011);
• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501
• 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
• 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 Clean Air Act; and
• Does not provide EPA with the discretionary authority to address, as
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).
Environmental protection, Air pollution control, Incorporation by Reference, Intergovernmental relations, Reporting and recordkeeping requirements, Sulfur oxides.