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that a waiver is appropriate for purposes of that different ozone NAAQS. VI. EPA’s Proposed Action

EPA is proposing approval of Illinois’ request to exempt the State’s 8-hour ozone nonattainment areas from the section 182(f) NO X RACT requirement. This proposed approval is based on EPA’s review of the evidence that the requirements of section 182(f)(1)(A), as elaborated upon in EPA’s guidance for section 182(f) exemptions, have beenmet for Chicago-Gary-Lake County, ILIN and St. Louis, MO-IL ozone nonattainment areas. In the future, if EPA determines that a violation of the 1997 8-hour ozone NAAQS has occurred in the Chicago-Gary-Lake County, IL-IN area (or at the Chiwaukee Prairie monitoring site in Kenosha County, Wisconsin) or in the St. Louis, MO-IL area while the Illinois portions of these ozone nonattainment areas are designated as nonattainment for the 1997 8-hour ozone NAAQS, EPA will take action to revoke the exemption.

Final approval of Illinois’ NO X RACT exemption request would suspend a requirement for a NO X RACT FIP stemming from EPA’s March 24, 2008, finding of Illinois’ failure to submit the NO X RACT rules. The suspension would remain in place contingent upon continued attainment of the 1997 8-hour ozone NAAQS in the Chicago-Gary-Lake County, IL-IN and St. Louis, MO-IL areas. If EPA approves a redesignation request for either of these areas for the 1997 8-hour ozone NAAQS, the NO X RACT FIP clock will permanently stop at that time. If EPA determines that there is a violation of the 1997 8-hour ozone NAAQS while either of these areas remain designated as nonattainment for the 1997 8-hour ozone NAAQS, the NO X RACT waiver will no longer be applicable as of the effective date of any such determination for the violating area by EPA. At that time, the NO X RACT FIP requirement will no longer be suspended and the NO X RACT FIP clock will restart at the point at which it stopped. EPA will provide notice in the Federal Register of any such waiver revocation and of the restarting of the NO X RACT FIP clock. VII. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA 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 CAA. Accordingly, this 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 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);

• 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 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 CAA; and

• Does not provide EPA with the discretionary authority to address, as appropriate, disproportionate human health or environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR 7629, February 16, 1994).

In addition, this rule does not have Tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the SIP is not approved to apply in Indian country located in the State, and EPA notes that it will not impose substantial direct costs on Tribal governments or preempt Tribal law. List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Intergovernmental relations, Nitrogen dioxide, Ozone, Volatile organic compounds.

Dated: November 23, 2010. Susan Hedman, Regional Administrator, Region 5.
[FR Doc. 2010–30840 Filed 12–7–10; 8:45 am]

**BILLING CODE 6560–50–P ENVIRONMENTAL PROTECTION**  **AGENCY**

**40 CFR Part 58**

**[EPA–HQ–OAR–2006–0735; FRL–9236–4]**

**Notice of Data Availability Regarding Two Studies of Ambient Lead**  **Concentrations Near a General Aviation Airport** 

**AGENCY :**  Environmental Protection Agency (EPA).

**ACTION :**  Notice of Data Availability (NODA).

**SUMMARY :**  The EPA issued a final rule on November 12, 2008, (effective date January 12, 2009) that revised the primary and secondary National Ambient Air Quality Standards (NAAQS) for lead and associated monitoring requirements. On December 30, 2009, EPA proposed revisions to the lead monitoring requirements. As part of the proposed revisions, EPA proposed requiring monitoring near general aviation airports estimated to have lead emissions of 0.50 tons per year or greater. After the proposal was published, EPA completed a study of ambient lead concentrations near a general aviation airport which may be referenced by the EPA in preparing the final lead monitoring requirements. In addition, a final report on one of the studies relied on in the proposed rule has become available. This action announces the availability of these two studies in the Revision to Lead Ambient Air Monitoring Requirements docket (EPA–HQ–OAR–2006–0735).

**FOR FURTHER INFORMATION CONTACT :**  For questions regarding the additional data, contact Kevin Cavender, Air Quality Assessment Division, C304–06, Environmental Protection Agency, U.S. EPA (C304–06), AQAD/AAMG, Research Triangle Park, NC 27711; telephone number: 919–541–2364; fax number: 919–541–1903; e-mail address : cavender.kevin@epa.gov.

**SUPPLEMENTARY INFORMATION :**  I. What is today’s action?

This action announces the availability of two studies that contain information on ambient lead concentrations near an airport that has lead emissions from the combustion of leaded aviation fuel. The first is a local-scale airport modeling and monitoring study conducted by the EPA to investigate near-source ambient lead concentrations attributable to lead from the combustion of leaded aviation gasoline (EPA, 2010). The second is a final report documenting the study relied on in the proposed rule which was used to identify airports as having


### 76337 Federal Register / Vol. 75, No. 235 / Wednesday, December 8, 2010 / Proposed Rules

the potential to exceed the lead NAAQS (South Coast Air Quality Management District, 2010). Both studies are located in Docket ID No. EPA–HQ–OAR–2006–
0735.

II. How does this information relate to the Proposed Rule—revisions to lead ambient air monitoring requirements?

These two studies provide information on the potential for lead emissions from the combustion of leaded aviation fuel at airports to exceed the lead NAAQS as well as other information (locations of maximum emissions and lead concentration gradients) that may be referenced in the final rule.

The first study developed and evaluated an air quality modeling approach that could be used to evaluate local-scale concentrations of lead in thevicinity of an airport where pistonengine aircraft are operated. The study also included an assessment of the maximum 3-month average lead concentration and model sensitivity tests. The maximum 3-month average lead concentration was evaluated in order to compare the model output with the NAAQS for lead, 0.15 μg/m3, reported as the maximum 3-month average concentration.

Air monitoring was conducted to evaluate the performance of the air modeling approach, to assist in the quantification of the contribution of lead from general aviation emissions to local air quality, and to provide information about the change in lead concentrations with distance from the airport. Air quality modeling was conducted using EPA’s American Meteorological Society/Environmental Protection Agency Regulatory Model or AERMOD. Inputs to the model included a comprehensive lead emissioninventory incorporating on-site, time-inmode and sub-daily activity data for piston engine aircraft. Model inputs alsoincluded considerations of aircraftinduced wake turbulence, plume rise of the aircraft exhaust, and allocation of approach and climb-out emissions to 50 meter increments in altitude.

To evaluate the modeling approach used here, ambient lead concentrations were measured upwind and downwind of the Santa Monica Airport and compared to modeled air concentrations. Modeling results paired in both time and space with monitoring data showed excellent overall agreement. Modeling results show aircraft engine run-up is the most important source contribution to the maximum lead concentration. Sensitivity analysis shows that engine run-up time, lead concentration in aviation gasoline, and the fraction of piston engine aircraft that are twin engine are the most important parameters in determining near-field lead concentrations. Year-long air quality modeling for 2008 and sensitivity analysis for the maximum 3-month average concentration period suggest the potential for 3-month average lead concentrations that exceed the current NAAQS for lead (0.15 μg/

m 3 ) and help inform the process for identifying locations of maximum concentration.

The second study is the final report on one of the airport studies referenced in the proposed rule. This report provides additional information on the approach, methods, and results of the study. III. How can I get a copy of these documents and other related information?

1. Docket. EPA has established a docket for this action under Docket ID No. EPA–HQ–OAR–2006–0735. All documents in the docket are listed on the http://www.regulations.gov Web site. Although listed in the index, some information is not publicly available,
e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through http://www.regulations.gov or in hard copy at the Revisions to Lead Ambient Air Monitoring Requirements docket, Docket ID No. EPA–OAR–2006–0735, EPA Docket Center, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30 p.m. Monday through Friday excluding legal holidays. The docket telephone number is (202) 566–1742. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566–1744.

2. Electronic Access. You may access this Federal Register document electronically through the EPA Internet under the ‘‘ Federal Register’’ listings at http://www.epa.gov/fedrgstr/

. IV. References
U.S. EPA (2010) Development and evaluation of an air quality modeling approach for lead emissions from piston-engine aircraft operating on leaded aviation gasoline. EPA–420–R–10–007. Available at http://www.epa.gov/otaq/ aviation.htm. South Coast Air Quality Management District (2010) General Aviation Airport Air Monitoring Study Final Report. Final Report. List of Subjects in 40 CFR Part 58

Ambient air monitoring, Air pollution control, Environmental protection, Intergovernmental relations, Reporting and recordkeeping requirements.

Dated: December 2, 2010. Mary E. Henigin, Acting Director, Office of Air Quality Planning and Standards.
[FR Doc. 2010–30849 Filed 12–7–10; 8:45 am]

**BILLING CODE 6560–50–P**

**ENVIRONMENTAL PROTECTION AGENCY** 

**40 CFR Parts 85, 86, and 600**

**DEPARTMENT OF TRANSPORTATION**

**National Highway Traffic Safety Administration** 

**49 CFR Parts 531 and 533**

**[EPA–HQ–OAR–2010–0799; FRL–9235–8; NHTSA–2010–0131]** 

**RIN 2060–AQ54; RIN 2127–AK79**

**2017 and Later Model Year Light-Duty Vehicle GHG Emissions and CAFE**  **Standards: Supplemental Notice of Intent** 

**AGENCIES :**  Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA), Department of Transportation (DOT).

**ACTION :**  Supplemental Notice of Intent to conduct a joint rulemaking.

**SUMMARY :**  On May 21, 2010, President Obama issued a Presidential Memorandum requesting that the Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA), on behalf of the Department of Transportation, develop, through notice and comment rulemaking, a coordinated National Program under the Clean Air Act (CAA) and the Energy Policy and Conservation Act (EPCA), as amended by the Energy Independence and Security Act (EISA), to improve fuel economy and to reduce greenhouse gas emissions of light-duty vehicles for model years 2017–2025. President Obama requested that the agencies issue a Notice of Intent (NOI) to issue a proposed rulemaking that announces plans for setting stringent fuel economy and greenhouse gas emissions standards for light-duty