# Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A2012-13828 ## Record - **Collection:** Federal Register - **Document type:** Rule - **Published:** June 18, 2012 - **Citation:** 77 FR 36342 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 87 and 1068 [EPA-HQ-OAR-2010-0687; FRL-9678-1] RIN 2060-AO70 Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is adopting several new aircraft engine emission standards for oxides of nitrogen (NO X ), compliance flexibilities, and other regulatory requirements for aircraft turbofan or turbojet engines with rated thrusts greater than 26.7 kilonewtons (kN). We also are adopting certain other requirements for gas turbine engines that are subject to exhaust emission standards as follows. First, we are clarifying when the emission characteristics of a new turbofan or turbojet engine model have become different enough from its existing parent engine design that it must conform to the most current emission standards. Second, we are establishing a new reporting requirement for manufacturers of gas turbine engines that are subject to any exhaust emission standard to provide us with timely and consistent emission-related information. Third, and finally, we are establishing amendments to aircraft engine test and emissions measurement procedures. EPA actively participated in the United Nations' International Civil Aviation Organization (ICAO) proceedings in which most of these requirements were first developed. These regulatory requirements have largely been adopted or are actively under consideration by its member states. By adopting such similar standards, therefore, the United States maintains consistency with these international efforts. DATES: These final rules are effective on July 18, 2012. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of July 18, 2012. ADDRESSES: EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2010-0687. 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 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 electronically through http://www.regulations.gov or in hard copy at the EPA Docket Center, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW., Washington, DC. 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, and the telephone number for the Air Docket is 202-566-1742. FOR FURTHER INFORMATION CONTACT: Richard Wilcox, Office of Transportation and Air Quality, Office of Air and Radiation, Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105; telephone number: (734) 214-4390; fax number: (734) 214-4816; email address: wilcox.rich@epa.gov. SUPPLEMENTARY INFORMATION: Does this action apply to me? Entities potentially regulated by this action are those that manufacture and sell aircraft engines and aircraft in the United States. Regulated categories include: Category NAICS a Codes SIC b Codes Examples of potentially affected entities Industry 336412 3724 Manufacturers of new aircraft engines. Industry 336411 3721 Manufacturers of new aircraft. a North American Industry Classification System (NAICS). b Standard Industrial Classification (SIC) system code. This table lists the types of entities that EPA is now aware could potentially be regulated by this action. Other types of entities not listed in the table could also be regulated. To determine whether your activities are regulated by this action, you should carefully examine the applicability criteria in 40 CFR 87.1 (part 87). If you have any questions regarding the applicability of this action to a particular entity, consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. Table of Contents I. Executive Summary II. Overview and Background A. Contents of the Final Rule B. EPA's Authority and Responsibilities Under the Clean Air Act C. Interaction With the International Community D. Brief History of EPA's Regulation of Aircraft Engine Emissions E. Brief History of ICAO Regulation of Aircraft Engine Emissions III. Why is EPA taking this action? A. Inventory Contribution B. Health, Environmental and Air Quality Impacts 1. Background on Ozone, PM and NO X a. What is ozone? b. What is particulate matter? c. What is NO X ? 2. Health Effects Associated With Exposure to Ozone, PM and NO X a. What are the health effects of ozone? b. What are the health effects of PM? c. What are the health effects of NO X ? 3. Environmental Effects Associated With Exposure to Ozone, PM and NO X a. Deposition of Nitrogen b. Visibility Effects c. Plant and Ecosystem Effects of Ozone 4. Impacts on Ambient Air Quality IV. Details of the Final Rule A. NO X Standards for Newly-Certified Engines 1. Tier 6 NO X Standards for Newly-Certified Engines a. Numerical Emission Limits for Higher Thrust Engines b. Numerical Emission Limits for Lower Thrust Engines 2. Tier 8 NO X Standards for Newly-Certified Engines a. Numerical Emission Limits for Higher Thrust Engines b. Numerical Emission Limits for Lower Thrust Engines B. Application of NO X Standards for Newly-Manufactured Engines 1. Phase-In of the Tier 6 NO X Standards for Newly-Manufactured Engines 2. Carryover of Previously Generated Emission Data 3. Exemptions and Exceptions From the Tier 6 Production Cutoff a. New Provisions for Spare Engines b. New Provisions for Engines Installed in New Aircraft i. Time-Frame and Scope ii. Production Limit iii. Exemption Requests iv. Coordination of Exemption Requests v. Low-Volume, Time-Limited Transitional Exception Program c. Voluntary Emission Offsets 4. Potential Phase-In of New Tier 8 NO X Standards for Newly-Manufactured Engines C. Application of Standards for Derivative Engines D. Annual Reporting Requirement E. Standards for Supersonic Aircraft Turbine Engines F. Amendments to Test and Measurement Procedures G. Possible Future Revisions to Emission Standards for New Technology Turbine Engines and Supersonic Aircraft Turbine Engines V. Description of Other Revisions to the Regulatory Text A. Applicability Issues 1. Military Engines 2. Noncommercial Engines B. Non-Substantive Revisions C. Clarifying Language for Regulatory Text VI. Technical Feasibility and Cost Impacts VII. Consultation With FAA VIII. Public Participation IX. Statutory Provisions and Legal Authority X. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review, and Executive Order 13563: Improving Regulation and Regulatory Review B. Paperwork Reduction Act C. Regulatory Flexibility Analysis D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments G. Executive Order 13045: Protection of Children From Environmental Health & Safety Risks H. Executive Order 13211: Actions That Significantly Affect Energy Supply, Distribution, or Use I. National Technology Transfer Advancement Act J. Executive Order 12898: Federal Actions To Address Environmental Justice in Minority Populations and Low Income Populations K. Congressional Review Act L. Executive Order 13609: Promoting International Regulatory Cooperation I. Executive Summary A. Purpose of the Regulatory Action The primary purpose of this rule is to adopt new oxides of nitrogen (NO X ) emission standards for aircraft engines with rated thrusts greater than 26.7 kN thrust. These are mostly commercial passenger and freighter aircraft in common use at airports across the U.S. It does not include engines used on military aircraft. NO X is strongly correlated with NO 2 , for which EPA has established National Ambient Air Quality Standards (NAAQS), i.e., a criteria pollutant, and it is an important precursor gas in the formation of tropospheric ozone and secondary particulate matter which are common air pollutants in urban areas where airports are located. Currently, approximately 154 million people live in areas designated nonattainment for one or more of the current NAAQS. This rule will allow us to enforce in the U.S. the emission standards adopted by ICAO, and will be useful to states in attaining or maintaining the ozone, PM 2.5 , and NO 2 NAAQS standards. This rule also contains several provisions to facilitate the implementation of EPA's aircraft engine emission regulations and related requirements. It is also important to note that adoption of the provisions in this rule meets U.S. treaty obligations under the Chicago Convention of 1944 by aligning our regulations with those in the International Civil Aviation Organization Annex 16, Volume II (adopted in 2010) that the U.S. helped to develop and support as part of the international process. This rule is being implemented under the authority provided in section 231 of the Clean Air Act (42 U.S.C. 7571), which directs the Administrator of EPA to, from time to time, propose aircraft engine emission standards applicable to the emission of any air pollutant from classes of aircraft engines which in her judgment causes or contributes to air pollution that may reasonably be anticipated to endanger public health or welfare. B. Summary of Major Provisions of the Regulatory Action The rule contains six major provisions. The first two provisions are new NO X emission standards for newly certified-engine models. The first standards, Tier 6, take effect when this rule becomes effective. These represent approximately a 12 percent reduction from current Tier 4 levels. They were actually adopted by ICAO in 2005 with an implementation date in 2008. The second standards, Tier 8, were adopted by ICAO in 2008 and take effect in 2014. These represent approximately a 15 percent reduction from Tier 6 levels. As noted above, both tiers of emission standards are needed to address local air quality concerns (NAAQS) and to meet U.S. treaty obligations under the Chicago Convention. The third major provision is a production cut-off for newly-manufactured engines (as opposed to newly-certified engines) which basically requires that after December 31, 2012 all newly-manufactured engines must meet at least Tier 6 NO X emission standards. This is also needed to meet our obligations under the Chicago Convention. The production cut-off is needed to ensure that the emission reductions envisioned by the emission standards are achieved on new production engines. The fourth major provision is related to potential exemptions or exceptions to the production cut-off requirement. These include revised provisions allowing manufacturers to request that FAA in consultation with EPA grant exemptions from the production cut-off for a designated number of engines within a prescribed time frame. These also include a low-volume, time-limited exception provision that will exclude several engines from the production cutoff. Both of these provisions help to assure an orderly transition to the new standards for engines needing more time to comply or for a few engines at the end of their production life. Finally, the rule includes a set of provisions which may be considered as minor if viewed separately, but collectively are important in upgrading EPA's regulations by incorporating some related agreements from our ICAO process and clarifying and improving existing provisions. Examples of this include special provisions for spare engines, provisions related to derivative engine models, test procedure specifications and reporting requirements. These changes are important for an effective implementation of the new requirements, and in many cases are also needed to meet our obligations under the Chicago Convention. C. Costs and Benefits This is not an economically significant regulatory action. Aircraft engines are international commodities used on aircraft manufactured and sold around the world. When developing new engine models manufacturers not only consider current emission requirements but also try to anticipate the stringency of future standards and respond appropriately. Engine manufacturers participated in the deliberations leading up to ICAO decisions on the aircraft engine NO X emission standards and after the ICAO decisions they incorporated engine technology changes as needed to meet the new ICAO requirements. This helps to ensure the world wide acceptability of their products. Essentially all of these changes are now complete. Thus, while there is some cost to a manufacturer for responding to the new ICAO provisions, there is no significant further direct cost to the manufacturers created by EPA's adopting the requirements into U.S regulations. In fact, it is likely that our adopting these requirements facilitates the acceptance of U.S. type certificates by aircraft manufacturers and airlines around the world. II. Overview and Background This section summarizes the major provisions of the final rule for aircraft gas turbine engines. It also contains background on the EPA's standard setting authority and responsibilities under the Clean Air Act, the connection between our emission standards and those of the international community, and a brief regulatory history for this source of emissions. A. Contents of the Final Rule We are adopting several new emission standards and other regulatory requirements for aircraft turbofan and turbojet engines 1 with rated thrusts greater than 26.7 kilonewtons (kN). First, we are establishing two new tiers of more stringent emission standards for oxides of nitrogen (NO X ). 2 The standards apply differently to two classes of these engines, i.e., “newly-certified engines” and “newly-manufactured engines.” The newly-certified engine standards apply to aircraft engines that have received a new type certificate and have never been manufactured prior to the effective date of the new emission standards. Requirements for newly-manufactured engines apply to aircraft engines that were previously certified and manufactured in compliance with preexisting standards, and they require manufacturers to either comply with the newer standards by a specified future date or cease production of the affected engine models. Newly-manufactured engine standards are also sometimes referred to as “production cutoff” standards. Second, we are adopting certain time-limited flexibilities, i.e., the potential for exemptions or exceptions as defined in the regulations for newly-manufactured engines that may not be able to comply with the first tier of the NO X standards because of specific technical or economic reasons. 3 1 Turbofan and turbojet engines will be collectively referred to as turbofan engines hereafter for convenience. 2 As previously mentioned, these new NO X standards are identical to requirements established by ICAO. The stringency of any new emission standard is selected based on an assessment of the technical feasibility, cost, and environmental benefit of potential requirements. The NO X standards we are promulgating today will not affect fuel economy or have any practical effect on CO 2 emissions. (See International Civil Aviation Organization (ICAO), “Committee on Aviation Environmental Protection (CAEP), Eighth Meeting, Montreal, 1 to 12 February 2010, CAEP/8 NO X Stringency Cost-Benefit Analysis Demonstration Using APMT-IMPACTS,” CAEP/8-IP/30, December 1, 2010. A copy of this document is in docket number EPA-HQ-OAR-2010-0687.) 3 These exemption or exception provisions are conceptually the same as the ICAO exemption provisions and provide the same regulatory flexibilities to all engine manufacturers. We are also making a number of additional changes that would apply to a wider range of aircraft gas turbine engines 4 than those that would be subject to the new emission standards. 5 First, we are defining the meaning of a derivative engine for emissions certification purposes. The intent of this definition is to distinguish when the emission characteristics of a new turbofan engine model vary sufficiently from its existing parent engine design, and must show compliance with the emission standard for a newly-certificated engine. Second, we are establishing new reporting requirements for manufacturers that produce gas turbine engines subject to any exhaust emission standard. This will provide us with timely and consistent emission data and other information that is necessary to conduct emission inventory and air quality analyses and develop appropriate public policy for the aviation sector. Specifically, reports are required for turbofan engines with rated thrusts greater than 26.7 kN, which are subject to gaseous emission and smoke standards, in addition to turbofans less than or equal to 26.7 kN, and all turboprop engines, that are only subject to smoke standards. 6 Third, we are adopting minor amendments to the test and measurement procedures for aircraft engines. Finally, as described in section IV, we are making minor amendments to regulator provisions addressing definitions, acronyms and abbreviations, general applicability and requirements, exemptions, and incorporation by reference. 4 The term gas turbine engine includes turbofan, turbojet, and turboprop engines designs. The rated output for turbofan and turbojet engines is normally expressed as kilonewtons (kN) thrust. The rated output for turboprop engines is normally expressed as shaft horsepower (hp) or shaft kilowatt (kW). 5 This includes turbofan and turbojet engines less than 26.7 kN thrust and all turboprop engines that are subject to any emission standard, e.g., smoke. 6 As discussed further in section III.D., the voluntary emission data report to ICAO does not include turbofans at or below 26.7 kN or turboprops subject to any emission standard. Most of these new regulatory requirements have already been adopted by the United Nation's International Civil Aviation Organization (ICAO). The requirements contained in this final rule bring the United States into alignment with the international standards and recommended practices. B. EPA's Authority and Responsibilities Under the Clean Air Act Section 231(a)(2)(A) of the Clean Air Act (CAA) directs the Administrator of EPA to, from time to time, propose aircraft engine emission standards applicable to the emission of any air pollutant from classes of aircraft engines which in her judgment causes or contributes to air pollution that may reasonably be anticipated to endanger public health or welfare. (See 42 U.S.C. 7571(a)(2)(A).) Section 231(a)(2)(B) directs EPA to consult with the Administrator of the Federal Aviation Administration (FAA) on such standards, and prohibits EPA from changing aircraft emission standards if such a change would significantly increase noise and adversely affect safety. 42 U.S.C. 7571(a)(2)(B)(i)-(ii). Section 231(a)(3) provides that after we propose standards, the Administrator shall issue such standards “with such modifications as he deems appropriate.” 42 U.S.C. 7571(a)(3). The U.S. Court of Appeals for the D.C. Circuit has held that this provision confers an unusually broad degree of discretion on EPA to adopt aircraft engine emission standards as the Agency determines are reasonable. NACAA v. EPA, 489 F.3d 1221 (D.C. Cir. 2007). In addition, under CAA section 231(b) EPA is required to ensure, in consultation with the U.S. Department of Transportation (DOT), that the effective date of any standard provides the necessary time to permit the development and application of the requisite technology, giving appropriate consideration to the cost of compliance. 42 U.S.C. 7571(b). Section 232 then directs the FAA to prescribe regulations to ensure compliance with EPA's standards. 42 U.S.C. 7572. Finally, section 233 of the CAA vests the authority to promulgate emission standards for aircraft or aircraft engines only in EPA. States are preempted from adopting or enforcing any standard respecting aircraft engine emissions unless such standard is identical to EPA's standards. 42 U.S.C. § 7573. Section VI of today's final rule further discusses our coordination with DOT through the FAA. 7 It also describes DOT's responsibility under the CAA to enforce the aircraft emission standards established by EPA. 7 The functions of the Secretary of Transportation under part B of title II of the Clean Air Act (§§ 231-234, 42 U.S.C. 7571-7574) have been delegated to the Administrator of the FAA. 49 CFR 1.47(g). C. Interaction With the International Community We began regulating the air pollution emissions from aircraft engines in 1973. Since that time, we have worked with the FAA and later with the International Civil Aviation Organization (ICAO) to develop international standards and other recommended practices pertaining to aircraft engine emissions. ICAO was established in 1944 by the United Nations (by the Convention on International Civil Aviation, the “Chicago Convention”) “* * * in order that international civil aviation may be developed in a safe and orderly manner and that international air transport services may be established on the basis of equality of opportunity and operated soundly and economically.” 8 ICAO's responsibilities include developing aircraft technical and operating standards, recommending practices, and generally fostering the growth of international civil aviation. The United States is currently one of 191 participating member States of ICAO. 9 10 8 ICAO, “Convention on International Civil Aviation,” Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO Web site located at www.icao.int. 9 Members of ICAO's Assembly are generally termed member States or contracting States. These terms are used interchangeably throughout this preamble. 10 There are currently 191 Contracting States according to ICAO Web site located at www.icao.int. In the interests of global harmonization and international air commerce, the Chicago Convention urges a high degree of uniformity by its member States. Nonetheless, the Convention also recognizes that member States may adopt their own unique airworthiness standards and that some may adopt standards that are more stringent than those agreed upon by ICAO. The Convention has a number of other features that govern international commerce. First, States that wish to use aircraft in international transportation must adopt emission standards and other recommended practices that are at least as stringent as ICAO's standards. States may ban the use of any aircraft within their airspace that does not meet ICAO standards. 11 Second, States are required to recognize the airworthiness certificates of any State whose standards are at least as stringent as ICAO's standards, thereby assuring that aircraft of any member State will be permitted to operate in any other member State. 12 Third, and finally, to ensure that international commerce is not unreasonably constrained, a participating nation which elects to adopt more stringent standards is obligated to notify ICAO of the differences between its standards and ICAO standards. 13 However, if a nation sets tighter standards than ICAO, air carriers not based in that nation would only be required to comply with ICAO standards or more stringent standards imposed by their own nations, if applicable. 11 ICAO, “Convention on International Civil Aviation,” Article 87, Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO Web site located at www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf. 12 ICAO, “Convention on International Civil Aviation,” Article 33, Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO Web site located at www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf. 13 ICAO, “Convention on International Civil Aviation,” Articles 38, Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO Web site located at www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf. ICAO's Committee on Aviation Environmental Protection (CAEP) undertakes ICAO's technical work in the environmental field. The Committee is responsible for evaluating, researching, and recommending measures to the ICAO Council that address the environmental impact of international civil aviation. CAEP is composed of various task groups, work groups, and other committees whose contributing members include atmospheric, economic, aviation, environmental, and other professionals interested in aviation and environmental protection. At CAEP meetings, the United States is represented by the FAA, which plays an active role at these meetings. 14 EPA has historically been a principal participant in the development of U.S. policy in various ICAO/CAEP working groups and other international venues, assisting and advising FAA on aviation emissions, technology, and policy matters. If ICAO adopts a CAEP proposal for a new environmental standard, it then becomes part of ICAO standards and recommended practices (Annex 16 to the Chicago Convention). 15 16 14 Pursuant to the President's memorandum of August 11, 1960 (and related Executive Order No. 10883 from 1960), the Interagency Group on International Aviation (IGIA) was established to facilitate coordinated recommendations to the Secretary of State on issues pertaining to international aviation. The DOT/FAA is the chair of IGIA, and as such, the FAA represents the U.S. on environmental matters at CAEP. 15 ICAO, “Aircraft Engine Emissions,” International Standards and Recommended Practices, Environmental Protection, Annex 16, Volume II, Second Edition, July 2008. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. 16 CAEP develops new emission standards based on an assessment of the technical feasibility, cost, and environmental benefit of potential requirements. D. Brief History of EPA's Regulation of Aircraft Engine Emissions As mentioned above, we initially regulated gaseous exhaust emissions, smoke, and fuel venting from aircraft engines in 1973. 17 Since that time, we have occasionally revised those regulations. Two of these revisions are most pertinent to today's final rule. First, in a 1997 rulemaking, we made our emission standards and test procedures more consistent with those of ICAO for turbofan engines used in commercial aviation with rated thrusts greater than 26.7kN. 18 These ICAO requirements are generally referred to as CAEP/2 standards. (The numbering nomenclature for CAEP requirements is discussed in the next section.) That action included new NO X emission standards for newly-manufactured commercial turbofan engines (those engines built after the effective date of the regulations that were already certified to pre-existing standards) 19 and for newly-certified commercial turbofan engines (those engine models that received their initial type certificate after the effective date of the regulations). It also included a CO emission standard for newly-manufactured commercial turbofan engines. Second, in our most recent rulemaking in 2005, we promulgated more stringent NO X emission standards for newly-certified commercial turbofan engines. 20 That final rule brought the U.S. standards closer to alignment with ICAO CAEP/4 requirements that were effective in 2004. In ruling on a petition for judicial review of the 2005 rule filed by the National Association of Clean Air Agencies (NACAA), the U.S. Court of Appeals held that EPA's approach of tracking the ICAO standards was reasonable and permissible under the CAA. NACAA v. EPA, 489 F.3d 1221, 1230-32 (D.C. Cir. 2007). 17 U.S. EPA, “Emission Standards and Test Procedures for Aircraft;” Final Rule, 38 FR 19088, July 17, 1973. 18 U.S. EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Final Rule, 62 FR 25356, May 8, 1997. While ICAO's standards were not limited to “commercial” aircraft engines, our 1997 standards were explicitly limited to commercial engines, as our finding that NO X and CO emissions from aircraft engines cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare was so limited, See 62 FR 25358. As explained later in section IV.A.2. of today's notice, we are expanding the scope of that finding and of our standards pursuant to section 231(a)(2)(A) of the Clean Air Act to include such emissions from both commercial and non-commercial aircraft engines based on the physical and operational similarities between commercial and noncommercial civilian aircraft and to bring our standards into full alignment with ICAO's. 19 This does not mean that in 2005 we promulgated requirements for the re-certification or retrofit of existing in-use engines. 20 U.S. EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Final Rule, 70 FR 2521, November 17, 2005. E. Brief History of ICAO Regulation of Aircraft Engine Emissions The first international standards and recommended practices for aircraft engine emissions was recommended by CAEP's predecessor, the Committee on Aircraft Engine Emissions (CAEE), and adopted by ICAO in 1981. 21 These standards limited aircraft engine emissions of HC, CO, and NO X . In 1994, ICAO adopted a CAEP/2 proposal to tighten the original NO X standard by 20 percent and amend the test procedures. 22 At the next CAEP meeting (CAEP/3) in 1995, the Committee recommended a further tightening of 16 percent and additional test procedure amendments, but in 1997 the ICAO Council rejected this stringency proposal and approved only the test procedure amendments. At the CAEP/4 meeting in 1998, the Committee adopted a similar 16 percent NO X reduction proposal, which ICAO approved on 1998. The CAEP/4 standards applied only to new engine designs certified after December 31, 2003 (i.e., the requirements did not also apply to previously certified, newly-manufactured engines unlike the CAEP/2 standards). In 2004, CAEP/6 recommended a 12 percent NO X reduction, which ICAO approved in 2005. 23 24 The CAEP/6 standards applied to new engine designs (newly-certified models) certified after December 31, 2007. At the most recent meeting, CAEP/8 recommended a further tightening of the NO X standards by 15 percent for newly-certified engines. 25 26 The Committee also recommended that the CAEP/6 standards be applied to newly-manufactured engines. ICAO approved these recommendations in 2011. 27 21 ICAO, Foreword of “Aircraft Engine Emissions,” International Standards and Recommended Practices, Environmental Protection, Annex 16, Volume II, Third Edition, July 2008. Copies of this document can be obtained from the ICAO Web site at www.icao.int. 22 CAEP conducts its work over a period of years. Each work cycle is numbered sequentially and that identifier is used to differentiate the results from one CAEP to another by convention. The first technical meeting on aircraft emission standards was CAEP's successor, i.e., CAEE. The first meeting of CAEP, therefore, is referred to as CAEP/2. 23 CAEP/5 did not address new aircraft engine emission standards. 24 ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 4 effective on July 20, 2008. Copies of this document can be obtained from the ICAO Web site at www.icao.int. 25 CAEP/7 did not address new aircraft engine emission standards. 26 ICAO, “Committee on Aviation Environmental Protection (CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 2010,” CAEP/8-WP/80. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. 27 ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 7 effective on July 18, 2011. Copies of this document can be obtained from the ICAO Web site at www.icao.int. III. Why is EPA taking this action? As mentioned above, section 231(a)(2)(A) of the CAA authorizes the EPA Administrator to “from time to time, issue proposed emission standards applicable to the emission of any air pollution from any class or classes of aircraft or aircraft engines which in his judgment causes, or contributes to air pollution which may reasonably be anticipated to endanger public health or welfare.” 42 U.S.C. 7571(a)(2)(A). One of the principal components of aircraft exhaust emissions is NO X , a precursor to the formation of tropospheric ozone and secondary PM. 28 Most commercial airports are located in urbanized areas 29 and many urbanized areas have ambient pollutant levels above the National Ambient Air Quality Standards (NAAQS) for ozone and fine particulate matter (PM 2.5 ) (i.e., they are in nonattainment for ozone and PM 2.5 ). 30 This section discusses the contribution of aircraft engines used in commercial service with rated thrusts greater than 26.7kN to the national NO X emissions inventory and to NO X emission inventories in selected ozone and PM 2.5 nonattainment areas, the potential effect of NO X emissions in the upper atmosphere on ground level PM 2.5 in addition to the health and welfare impacts of NO X and PM emissions. 28 Ground-level ozone, the main ingredient in smog, is formed by complex chemical reactions of volatile organic compounds (VOC) and NO X in the presence of heat and sunlight. Standards that reduce NO X emissions will help address ambient ozone levels. They can also help reduce particulate matter (PM) levels as NO X emissions can also be part of the secondary formation of PM. See Section II.B below. 29 According to Airport Council International—North America and similar FAA databases, most commercial operations occur at airports that are in or near large cities or urbanized areas. There are about 130 commercial airports in 78 ozone and fine particulate nonattainment areas (based on the nonattainment areas status of 2008). There are about 325 commercial airports in the U.S. 30 For a current list of nonattainment areas see: http://www.epa.gov/oar/oaqps/greenbk/index.html. A. Inventory Contribution In contrast to all other mobile sources, whose emissions occur completely at ground level, the emissions from aircraft and aircraft engines can be divided into two flight regimes. The first regime includes the emissions that are released in the lower layer of the atmosphere and directly affect local and regional ambient air quality. These emissions generally occur at or below 3,000 feet above ground level, i.e., during the landing and takeoff (LTO) cycle. The aircraft operations that comprise an LTO cycle are: engine idle at the terminal gate (and sometimes during ground delays while holding for the active runway); taxiing between the terminal and the runway; take-off; climb-out; and approach to the airport. The second regime includes emissions that occur above 3,000 feet above ground level, known as non-LTO emissions. Collectively, the emissions associated with all ground and flight operations are generally referred to as full flight emissions. In this section, we will discuss NO X emission inventories for commercial turbine-engine aircraft, both nationally and for selected ozone and PM 2.5 nonattainment areas (NAAs). These inventories reflect emissions during the landing and takeoff cycle only. The most recent comprehensive analysis of historical and current LTO emissions from aircraft engines comes from a study undertaken for us by Eastern Research Group (ERG). 31 The study analyzed the national emissions of commercial aircraft operations in the United States, and showed that in the most recent year studied (2008), such aircraft LTO operations contributed about 97 thousand tons to the national NO X inventory. 32 A summary of the national inventory of LTO NO X emissions is shown in Table 1. 31 “Historical Assessment of Aircraft Landing and Take-off Emissions (1986-2008),” Eastern Research Group, May 2011. A copy of this document can be found in public docket EPA-HQ-OAR-2010-0687. 32 The cumulative LTO NO X reduction associated with the new NO X standards is projected to be about 100,000 tons from 2014 to 2030 (2014 is the implementation date of the CAEP/8 NO X standards). See “Historical Assessment of Aircraft Landing and Take-off Emissions (1986-2008),” Eastern Research Group, May 2011. A copy of this document can be found in public docket EPA-HQ-OAR-2010-0687. When these nationwide LTO emissions are compared to the total U.S. mobile source inventory for 2009, they account for less than one percent of the total. However, such a comparison may be a bit misleading, as it only includes those aircraft emissions that occur below 3,000 feet altitude, while comparing them to the entirety of other mobile source emissions. In the U.S., LTO emissions account for only about ten percent of full flight NO X emissions. When considering full flight aircraft emissions (i.e., including both LTO and non-LTO emissions), the contribution of aircraft to the total mobile source NO X inventory is approximately 7.7 percent. 33 It is also worth noting that these LTO emissions are more localized in that they occur near airports, which are mostly within urban areas. 33 U.S. EPA, “Comparison of Aircraft LTO and Full Flight NO X Emissions to Total Mobile Source NO X Emissions,” memorandum from John Mueller, Assessment and Standards Division, Office of Transportation and Air Quality, to docket EPA-HQ-OAR-2010-0687, May 10, 2011. Table 1—Current National NO X Emissions From Commercial Aircraft Aircraft category 2008 Total NO X (thousand tons) Air Carrier 86 Commuter/Air Taxi 11 Total Commercial 97 In addition, it is important to assess the contribution of commercial aircraft LTO NO X emissions on a local level, especially in areas containing or adjacent to airports. The historical analysis conducted by ERG also included an assessment of selected ozone nonattainment areas (NAAs). The NAAs selected for study were chosen as follows. First, the 25 NAAs with airports which had high commercial traffic volumes were identified. Second, the 25 NAAs with the largest population were identified. These lists were combined. However, there was some overlap, and this led to a total of 40 NAAs being identified for the study. 34 These NAAs collectively include 200 airports, accounting for about 70 percent of commercial air traffic operations. 34 Although 41 NAAs were studied, the non-aircraft emissions data source that the aircraft emissions were compared to for this analysis did not distinguish between the Boston NAA in Massachusetts and the greater Boston NAA in New Hampshire. Thus, aircraft emissions from those two NAAs were combined into a single NAA for the purpose of this analysis, yielding 40 NAAs for study. Of the 40 NAAs originally studied by ERG as previously described, we identified the 30 areas that were in nonattainment for ozone or PM 2.5 as of March 30, 2012. 35 Current (2008) and projected (2020) NO X emissions for these 30 ozone and PM 2.5 NAAs, as well as the percent contribution of aircraft to total mobile source inventories (as compared to 2005 and 2020 mobile source inventories), are shown in Table 2. 36 37 38 The relative contribution of aircraft in any given NAA varies based on activity in other transportation and industrial sectors. As can be seen from this table, expected growth in aircraft operations in many of these areas combined with anticipated reductions in NO X emissions from other mobile source categories results in the growth of the relative contribution of aircraft LTO emissions to mobile source NO X emissions in NAAs. 35 For a current list of nonattainment areas see: http://www.epa.gov/oar/oaqps/greenbk/index.html. 36 U.S. EPA, “Relative Contribution of Aircraft to Total Mobile Source NO X Emissions in Selected Ozone Nonattainment Areas,” memorandum from John Mueller, Assessment and Standards Division, Office of Transportation and Air Quality, to docket EPA-HQ-OAR-2010-0687, May 10, 2011. 37 U.S. EPA, “Addendum to ‘Relative Contribution of Aircraft to Total Mobile Source NO X Emissions in Selected Ozone Nonattainment Areas,’ ” memorandum from John Mueller, Assessment and Standards Division, Office of Transportation and Air Quality, to docket EPA-HQ-OAR-2010-0687, May 17, 2011. 38 U.S. EPA, “Update to ‘Relative Contribution of Aircraft to Total Mobile Source NO X Emissions in Selected Ozone Nonattainment Areas,’ ” memorandum from John Mueller, Assessment and Standards Division, Office of Transportation and Air Quality, to docket EPA-HQ-OAR-2010-0687, April 30, 2012. Table 2—NO X Emissions in Selected Ozone and PM 2.5 Nonattainment Areas Nonattainment area 2008 Total NO X (tons) 2008 Aircraft percent of mobile source NO X 2020 Aircraft percent of mobile source NO X Atlanta, GA 5,808 2.6 8.2 Baltimore, MD 1,148 1.3 4.4 Boston—including MA and NH NAAs 2,032 1.0 2.7 Charlotte-Gastonia-Rock Hill, NC-SC 1,917 2.6 10.0 Chicago-Gary-Lake County, IL-IN 6,007 1.8 5.0 Cleveland-Akron-Lorain, OH 680 0.5 1.3 Dallas-Fort Worth, TX 3,880 1.7 6.9 Denver-Boulder-Greeley-Fort Collins-Loveland, CO 2,649 2.5 7.1 Detroit-Ann Arbor, MI 2,312 1.1 3.0 Greater Connecticut, CT 405 0.8 2.4 Houston-Galveston-Brazoria, TX 3,045 1.3 3.4 Indianapolis, IN 1,089 1.4 3.0 Las Vegas, NV 2,308 6.0 15.8 Los Angeles South Coast Air Basin, CA 6,479 1.5 4.5 Louisville, KY-IN 1,211 1.9 6.2 Milwaukee-Racine, WI 557 0.9 3.2 New York-N. New Jersey-Long Island, NY-NJ-CT 10,093 2.3 6.3 Philadelphia-Wilmington-Atlantic City, PA-NY-MD-DE 2,308 1.0 2.8 Phoenix-Mesa, AZ 2,298 1.4 3.3 Pittsburgh-Beaver Valley, PA 480 0.5 1.1 Providence (entire State), RI 232 1.0 2.3 Riverside County (Coachella Valley), CA 70 0.2 0.5 Sacramento Metro, CA 603 1.0 2.0 Salt Lake City, UT 1,235 4.4 14.1 San Diego, CA 1,035 1.4 3.4 San Francisco Bay Area, CA 4,405 2.7 6.7 San Joaquin Valley, CA 74 0.0 0.1 Seattle-Tacoma, WA 1,958 1.4 3.9 St. Louis, MO-IL 810 0.6 1.6 Washington, DC-MD-VA 2,983 2.0 6.2 Table 3 shows how commercial aircraft operations are projected to rise in the future on a nationwide basis. As operations increase, the inventory impact of these aircraft on national and local NO X inventories will also increase. Table 3—Current and Projected Commercial Aircraft Operations Year Air carrier operations (millions) Commuter/air taxi operations (millions) Total commercial operations (millions) Total increase in commercial operations over 2008 (percent) 2008 14.1 13.8 27.9 2020 16.5 14.1 30.5 9 2030 20.6 16.0 36.6 31 Source: December 2010 FAA TAF, which is located at http://aspm.faa.gov/main/taf.asp. B. Health, Environmental and Air Quality Impacts NO X emissions from aircraft and other mobile and stationary sources contribute to the formation of ozone. In addition, NO X emissions at low altitude also react in the atmosphere to form secondary fine particulate matter (PM 2.5 ), particularly ammonium nitrate. In the following sections we discuss the adverse health and welfare effects associated with NO X emissions, in addition to the current and projected levels of ozone and PM across the country. The ICAO NO X standards with which we are aligning will help reduce ambient ozone and secondary PM levels and thus will help areas with airports achieve or maintain attainment with the National Ambient Air Quality Standards (NAAQS). 39 39 The discussion of PM health and welfare effects throughout this notice relates exclusively to the effects of the NO X emission standards on the formation of secondary PM from nitrate formation in the atmosphere. Presently, there are no emission standards for PM emitted directly from aircraft turbine engines. The current and planned future work programs for CAEP/ICAO are developing PM test procedures and information to characterize the amount and type of these emissions from aircraft engines that are in production. Ultimately, this information will be used to assess the need for an aircraft turbine engine PM standard (i.e., whether PM emissions from aircraft cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare), with standard setting as appropriate. 1. Background on Ozone, PM and NO X a. What is ozone? Ground-level ozone pollution is typically formed through reactions involving VOC and NO X in the lower atmosphere in the presence of sunlight. These pollutants, often referred to as ozone precursors, are emitted by many types of pollution sources, such as highway and nonroad motor vehicles and engines, power plants, chemical plants, refineries, makers of consumer and commercial products, industrial facilities, and smaller area sources. The science of ozone formation, transport, and accumulation is complex. 40 Ground-level ozone is produced and destroyed in a cyclical set of chemical reactions, many of which are sensitive to temperature and sunlight. When ambient temperatures and sunlight levels remain high for several days and the air is relatively stagnant, ozone and its precursors can build up and result in more ozone than typically occurs on a single high-temperature day. Ozone and its precursors can be transported hundreds of miles downwind from precursor emissions, resulting in elevated ozone levels even in areas with low local VOC or NO X emissions. 40 U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document is available in Docket EPA-HQ-OAR-2010-0687. This document may be accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html. b. What is particulate matter? The discussion includes PM 2.5 because the NO X emitted by aircraft engines can react in the atmosphere to form nitrate, a component of PM 2.5 . Particulate matter is a generic term for a broad class of chemically and physically diverse substances. It can be principally characterized as discrete particles that exist in the condensed (liquid or solid) phase spanning several orders of magnitude in size. Since 1987, EPA has delineated that subset of inhalable particles small enough to penetrate to the thoracic region (including the tracheobronchial and alveolar regions) of the respiratory tract (referred to as thoracic particles). The current PM NAAQS uses PM 2.5 as the indicator for fine particles (with PM 2.5 generally referring to particles with a nominal mean aerodynamic diameter less than or equal to 2.5 micrometers (µm)), and use PM 10 as the indicator for purposes of regulating the coarse fraction of PM 10 (referred to as thoracic coarse particles or coarse-fraction particles; generally including particles with a nominal mean aerodynamic diameter greater than 2.5 µm and less than or equal to 10 µm, or PM 10-2.5 ). Ultrafine particles are a subset of fine particles, generally less than 100 nanometers (0.1 μm) in diameter. Fine particles are produced primarily by combustion processes and by transformations of gaseous emissions (e.g., SO X , NO X and VOC) in the atmosphere. The chemical and physical properties of PM 2.5 may vary greatly with time, region, meteorology, and source category. Thus, PM 2.5 may include a complex mixture of different components including sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These particles can remain in the atmosphere for days to weeks and travel hundreds to thousands of kilometers. c. What is NO X ? Nitrogen dioxide (NO 2 ) is a member of the NO X family of gases. Most NO 2 is formed in the air from the oxidation of nitric oxide (NO) emitted when fuel is burned at a high temperature. NO 2 and its gas phase oxidation products can dissolve in water droplets and further oxidize to form nitric acid which reacts with ammonia to form nitrates, an important component of ambient PM. NO X and VOC are the two major precursors of ozone. The health effects of ozone, ambient PM and NO X are covered in section II.B.2. 2. Health Effects Associated With Exposure to Ozone, PM and NO X a. What are the health effects of ozone? The health and welfare effects of ozone are well documented and are assessed in EPA's 2006 Air Quality Criteria Document and 2007 Staff Paper. 41 42 People who are more susceptible to effects associated with exposure to ozone can include children, the elderly, and individuals with respiratory disease such as asthma. Those with greater exposures to ozone, for instance due to time spent outdoors (e.g., children and outdoor workers), are of particular concern. Ozone can irritate the respiratory system, causing coughing, throat irritation, and breathing discomfort. Ozone can reduce lung function and cause pulmonary inflammation in healthy individuals. Ozone can also aggravate asthma, leading to more asthma attacks that require medical attention and/or the use of additional medication. Thus, ambient ozone may cause both healthy and asthmatic individuals to limit their outdoor activities. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular-related morbidity and highly suggestive evidence that short-term ozone exposure directly or indirectly contributes to non-accidental and cardiopulmonary-related mortality, but additional research is needed to clarify the underlying mechanisms causing these effects. In a report on the estimation of ozone-related premature mortality published by the National Research Council (NRC), a panel of experts and reviewers concluded that short-term exposure to ambient ozone is likely to contribute to premature deaths and that ozone-related mortality should be included in estimates of the health benefits of reducing ozone exposure. 43 Animal toxicological evidence indicates that with repeated exposure, ozone can inflame and damage the lining of the lungs, which may lead to permanent changes in lung tissue and irreversible reductions in lung function. The respiratory effects observed in controlled human exposure studies and animal studies are coherent with the evidence from epidemiologic studies supporting a causal relationship between acute ambient ozone exposures and increased respiratory-related emergency room visits and hospitalizations in the warm season. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular-related morbidity and non-accidental and cardiopulmonary mortality. 41 U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document is available in Docket EPA-HQ-OAR-2010-0687. This document may be accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html. 42 U.S. EPA (2007) Review of the National Ambient Air Quality Standards for Ozone, Policy Assessment of Scientific and Technical Information. OAQPS Staff Paper.EPA-452/R-07-003. This document is available in Docket EPA-HQ-OAR-2010-0687. This document is available electronically at: http:www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp.html. 43 National Research Council (NRC), 2008. Estimating Mortality Risk Reduction and Economic Benefits From Controlling Ozone Air Pollution. The National Academies Press: Washington, DC A copy of this document is in docket number EPA-HQ-OAR-2010-0687. b. What are the health effects of PM? Scientific studies show ambient PM is associated with a series of adverse health effects. These health effects are discussed in detail in EPA's Integrated Science Assessment for Particulate Matter (ISA). 44 The ISA summarizes health effects evidence associated with both short-term and long-term exposures to PM 2.5 , PM 10-2.5 , and ultrafine particles. 44 U.S. EPA (2009) Integrated Science Assessment for Particulate Matter, EPA 600/R-08/139F. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. The ISA concludes that health effects associated with short-term exposures (hours to days) to ambient PM 2.5 include mortality, cardiovascular effects, such as altered vasomotor function and myocardial ischemia, and hospital admissions and emergency department visits for ischemic heart disease and congestive heart failure, and respiratory effects, such as exacerbation of asthma symptoms in children and hospital admissions and emergency department visits for chronic obstructive pulmonary disease and respiratory infections. 45 The ISA notes that long-term exposure (months to years) to PM 2.5 is associated with the development/progression of cardiovascular disease, premature mortality, and respiratory effects, including reduced lung function growth in children, increased respiratory symptoms, and asthma development. 46 The ISA concludes that the currently available scientific evidence from epidemiologic, controlled human exposure, and toxicological studies supports a causal association between short- and long-term exposures to PM 2.5 and cardiovascular effects and premature mortality. Furthermore, the ISA concludes that the collective evidence supports likely causal associations between short- and long-term PM 2.5 exposures and respiratory effects. The ISA also concludes that the scientific evidence is suggestive of a causal association for reproductive and developmental effects including respiratory-related infant mortality and cancer, mutagenicity, and genotoxicity and long-term exposure to PM 2.5 . 47 45 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, 2009. Section 2.3.1.1. 46 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, 2009. page 2-12, Sections 7.3.1.1 and 7.3.2.1. 47 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, 2009. Section 2.3.2. For PM 10-2.5 , the ISA concludes that the current evidence is suggestive of a causal relationship between short-term exposures and premature mortality, cardiovascular effects, and respiratory effects. Data are inadequate to draw conclusions regarding the health effects associated with long-term exposure to PM 10-2.5 . For ultrafine particles, the ISA concludes that there is suggestive evidence of a causal relationship between short-term exposures and cardiovascular effects, such as changes in heart rhythm and blood vessel function. It also concludes that there is suggestive evidence of association between short-term exposure to ultrafine particles and respiratory effects. Data are inadequate to draw conclusions regarding the health effects associated with long-term exposure to ultrafine particles. c. What are the health effects of NO X ? Information on the health effects of NO 2 can be found in the EPA Integrated Science Assessment (ISA) for Nitrogen Oxides. 48 The EPA has concluded that the findings of epidemiologic, controlled human exposure, and animal toxicological studies provide evidence that is sufficient to infer a likely causal relationship between respiratory effects and short-term NO 2 exposure. The ISA concludes that the strongest evidence for such a relationship comes from epidemiologic studies of respiratory effects including symptoms, emergency department visits, and hospital admissions. The ISA also draws two broad conclusions regarding airway responsiveness following NO 2 exposure. First, the ISA concludes that NO 2 exposure may enhance the sensitivity to allergen-induced decrements in lung function and increase the allergen-induced airway inflammatory response following 30-minute exposures of asthmatics to NO 2 concentrations as low as 0.26 ppm. Second, exposure to NO 2 has been found to enhance the inherent responsiveness of the airway to subsequent nonspecific challenges in controlled human exposure studies of asthmatic subjects. Small but significant increases in non-specific airway hyperresponsiveness were reported following 1-hour exposures of asthmatics to 0.1 ppm NO 2 . Enhanced airway responsiveness could have important clinical implications for asthmatics since transient increases in airway responsiveness following NO 2 exposure have the potential to increase symptoms and worsen asthma control. Together, the epidemiologic and experimental data sets form a plausible, consistent, and coherent description of a relationship between NO 2 exposures and an array of adverse health effects that range from the onset of respiratory symptoms to hospital admission. 48 U.S. EPA (2008). Integrated Science Assessment for Oxides of Nitrogen—Health Criteria (Final Report). EPA/600/R-08/071. Washington, DC: U.S. EPA. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. Although the weight of evidence supporting a causal relationship is somewhat less certain than that associated with respiratory morbidity, NO 2 has also been linked to other health endpoints. These include all-cause (non-accidental) mortality, hospital admissions or emergency department visits for cardiovascular disease, and decrements in lung function growth associated with chronic exposure. 3. Environmental Effects Associated With Exposure to Ozone, PM and NO X a. Deposition of Nitrogen Emissions of NO X from aircraft engines contribute to atmospheric deposition of nitrogen in the U.S. Atmospheric deposition of nitrogen contributes to acidification, altering biogeochemistry and affecting animal and plant life in terrestrial and aquatic ecosystems across the United States. The sensitivity of terrestrial and aquatic ecosystems to acidification from nitrogen deposition is predominantly governed by geology. Prolonged exposure to excess nitrogen deposition in sensitive areas acidifies lakes, rivers and soils. Increased acidity in surface waters creates inhospitable conditions for biota and affects the abundance and nutritional value of preferred prey species, threatening biodiversity and ecosystem function. Over time, acidifying deposition also removes essential nutrients from forest soils, depleting the capacity of soils to neutralize future acid loadings and negatively affecting forest sustainability. Major effects include a decline in sensitive forest tree species, such as red spruce ( Picea rubens ) and sugar maple ( Acer saccharum ); and a loss of biodiversity of fishes, zooplankton, and macro invertebrates. In addition to the role nitrogen deposition plays in acidification, nitrogen deposition also leads to nutrient enrichment and altered biogeochemical cycling. In aquatic systems increased nitrogen can alter species assemblages and cause eutrophication. In terrestrial systems nitrogen loading can lead to loss of nitrogen sensitive lichen species, decreased biodiversity of grasslands, meadows and other sensitive habitats, and increased potential for invasive species. Adverse impacts on soil chemistry and plant life have been observed for areas heavily influenced by atmospheric deposition of nutrients, metals and acid species, resulting in species shifts, loss of biodiversity, forest decline damage to forest productivity and reductions in ecosystem services. Potential impacts also include adverse effects to human health through ingestion of contaminated vegetation or livestock (as in the case for dioxin deposition), reduction in crop yield, and limited use of land due to contamination. Atmospheric deposition of pollutants can reduce the aesthetic appeal of buildings and culturally important articles through soiling, and can contribute directly (or in conjunction with other pollutants) to structural damage by means of corrosion or erosion. 49 Atmospheric deposition may affect materials principally by promoting and accelerating the corrosion of metals, by degrading paints, and by deteriorating building materials such as concrete and limestone. Particles contribute to these effects because of their electrolytic, hygroscopic, and acidic properties, and their ability to adsorb corrosive gases (principally sulfur dioxide). 49 U.S. EPA. (2005). Review of the National Ambient Air Quality Standards for Particulate Matter: Policy Assessment of Scientific and Technical Information, OAQPS Staff Paper. Retrieved on April 9, 2009 from http://www.epa.gov/ttn/naaqs/standards/pm/data/pmstaffpaper_20051221.pdf . b. Visibility Effects NO X emissions contribute to visibility impairment in the U.S. through the formation of secondary PM 2.5 . 50 Visibility impairment is caused by light scattering and absorption by suspended particles and gases. Visibility is important because it has direct significance to people's enjoyment of daily activities in all parts of the country. Individuals value good visibility for the well-being it provides them directly, where they live and work, and in places where they enjoy recreational opportunities. Visibility is also highly valued in significant natural areas, such as national parks and wilderness areas, and special emphasis is given to protecting visibility in these areas. For more information on visibility see the final 2009 PM ISA. 51 50 U.S. EPA. (2004). Air Quality Criteria for Particulate Matter (AQCD). Volume I Document No. EPA600/P-99/002aF and Volume II Document No. EPA600/P-99/002bF. Washington, DC: U.S. Environmental Protection Agency. Retrieved on March 18, 2009 from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87903 . 51 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/139F, 2009. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. c. Plant and Ecosystem Effects of Ozone Elevated ozone levels contribute to environmental effects, with impacts to plants and ecosystems being of most concern. Ozone can produce both acute and chronic injury in sensitive species depending on the concentration level and the duration of the exposure. Ozone effects also tend to accumulate over the growing season of the plant, so that even low concentrations experienced for a longer duration have the potential to create chronic stress on vegetation. Ozone damage to plants includes visible injury to leaves and impaired photosynthesis, both of which can lead to reduced plant growth and reproduction, resulting in reduced crop yields, forestry production, and use of sensitive ornamentals in landscaping. In addition, the impairment of photosynthesis, the process by which the plant makes carbohydrates (its source of energy and food), can lead to a subsequent reduction in root growth and carbohydrate storage below ground, resulting in other, more subtle plant and ecosystems impacts. These latter impacts include increased susceptibility of plants to insect attack, disease, harsh weather, interspecies competition and overall decreased plant vigor. The adverse effects of ozone on forest and other natural vegetation can potentially lead to species shifts and loss from the affected ecosystems, resulting in a loss or reduction in associated ecosystem goods and services. Lastly, visible ozone injury to leaves can result in a loss of aesthetic value in areas of special scenic significance like national parks and wilderness areas. The final 2006 Ozone Air Quality Criteria Document presents more detailed information on ozone effects on vegetation and ecosystems. 4. Impacts on Ambient Air Quality The aircraft NO X emission standards we are promulgating would affect ambient concentrations of air pollutants. Nationally, levels of PM 2.5 , ozone, and NO X are declining. 52 However as of March 30, 2012, over 15 million people live in areas designated nonattainment for one or more of the current NAAQS. 53 These numbers do not include the people living in areas where there is a future risk of failing to maintain or attain the NAAQS. 52 U. S. EPA (2010) Our Nation's Air: Status and Trends through 2008. Office of Air Quality Planning and Standards, Research Triangle Park, NC. Publication No. EPA 454/R-09-002. This document can be accessed electronically at: http://www.epa.gov/airtrends/2010/ . 53 U.S. EPA, 2012. http://www.epa.gov/oar/oaqps/greenbk/index.html States with ozone nonattainment areas are required to take action to bring those areas into attainment. The attainment date assigned to an ozone nonattainment area is based on the area's classification. Most ozone nonattainment areas are required to attain the 1997 8-hour ozone NAAQS in the 2007 to 2013 time frame and then to maintain it thereafter. 54 We anticipate designating areas for the 2008 ozone standards in late spring 2012; thus, the attainment dates for areas designated nonattainment for the 2008 8-hour ozone NAAQS would likely be in the 2015 to 2032 timeframe, depending on the severity of the problem in each area. 55 54 The Los Angeles South Coast Air Basin 8-hour ozone nonattainment area and the San Joaquin Valley Air Basin 8-hour ozone nonattainment area are designated as extreme and will have to attain before June 15, 2024. The Sacramento, Coachella Valley and Houston 8-hour ozone nonattainment areas are designated as severe and will have to attain by June 15, 2019. In addition, the Western Mojave 8-hour ozone nonattainment area has requested to be reclassified as severe. This request has not yet been acted on. 55 U.S. EPA, 2012. Proposed Rule—Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area Classifications Approach, Attainment Deadlines and Revocation of the 1997 Ozone Standards for Transportation Conformity Purposes. (77 FR 8107, February 14, 2012). Areas designated as not attaining the 1997 PM 2.5 NAAQS will need to attain the 1997 standards in the 2010 to 2015 time frame, and then maintain compliance with them thereafter. The 2006 24-hour PM 2.5 nonattainment areas will be required to attain the 2006 24-hour PM 2.5 NAAQS in the 2014 to 2019 time frame and then be required to maintain the 2006 24-hour PM 2.5 NAAQS thereafter. EPA has already adopted many emission control programs that are expected to reduce ambient ozone and PM 2.5 levels and which will assist in reducing the number of areas that fail to achieve the NAAQS. Even so, our air quality modeling projects that in 2030 as many as 10 counties with a population of over 30 million may not attain the 2008 ozone standard of 0.075 ppm (75 ppb) without additional controls. 56 In addition, our air quality modeling projects that in 2030 at least four counties with a population of nearly 7 million may not attain the 1997 annual PM 2.5 standard of 15 μg/m 3 and 22 counties with a population of over 33 million may not attain the 2006 24-hour PM 2.5 standard of 35 μg/m 3 without additional controls. 57 58 These numbers do not account for those areas that are close to (e.g., within 10 percent of) the standards. These areas, although not violating the standards, would also benefit from any reductions in NO X ensuring long-term maintenance of the NAAQS. 56 U.S. EPA (2010). Regulatory Impact Analysis: Final Rulemaking To Establish Greenhouse Gas Emission Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Chapter 8: Health and Environmental Impacts. EPA 420-R-11-901. 57 U.S. EPA (2010). Regulatory Impact Analysis: Final Rulemaking To Establish Greenhouse Gas Emission Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles. Chapter 8: Health and Environmental Impacts. EPA 420-R-11-901. 58 These figures are based on the results of EPA computer modeling, which is not affected by the upcoming 2008 ozone NAAQS nonattainment designations. In summary, the aircraft NO X reductions resulting from these new aircraft engine emission standards will be useful to states in attaining or maintaining the ozone, PM 2.5 , and NO 2 NAAQS standards. IV. Details of the Final Rule The following is a description of the regulations being adopted in this final rule, with any changes from the proposal also noted. The descriptions also include our response to the most significant comments received on the proposal. A full summary of the comments and our responses are contained in the response to comments document for the rule that is available in the public docket for this action. 59 59 U.S. Environmental Protection Agency, “Summary and Analysis of Comments: Control of Air Pollution From Aircraft and Aircraft Engines,” Office of Transportation and Air Quality, EPA-420-R-12-011, May 2012. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. We are establishing two different levels or “tiers” of increasingly more stringent NO X emission standards for gas turbofan engines with maximum rated thrusts greater than 26.7 kilonewtons (kN). 60 Each of the tiers apply to newly-certified engines. Newly-certified aircraft engines are those that would receive a new type certificate after the effective date of the applicable standards. Such engine types or models would not have begun production prior to the effective date of the new requirement. 61 60 The standards will apply to engines used in commercial and noncommercial aviation for which the FAA issues airworthiness certificates, e.g., non-revenue, general aviation service. The vast majority of these engines are used in commercial applications. 61 ICAO standards describe newly-certified engines as “* * * engines of a type or model for which the date of manufacture of the first individual production model was after. * * *” the effective date of the emission standards. See ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 4 effective on July 20, 2008. Copies of this document can be obtained from the ICAO Web site at www.icao.int. The term “first individual production model” means the first engine ever produced of a unique model or type. We are also requiring newly-manufactured engines to comply with the first tier of the two tiers of standards. Newly-manufactured aircraft engines are those that have been previously certified and manufactured in compliance with preexisting standards, and will continue to be produced after the effective date of a new applicable standard. Normally, these newly-manufactured engines must comply with the same NO X limits as newly-certified engines, but at a later date or cease production. 62 The end of this “phase-in” period for the newly-manufactured engine standards is sometimes referred to as a “production cutoff.”. Again, we are adopting only the first of the two new tiers of NO X standards for newly-manufactured engines. These provisions are described in detail below. 62 The standards for newly-manufactured engines are described in general regulatory terms as the date that the type or model was first certified and produced in conformance with specific emission standards, and the date beyond which an individual engine meeting those same requirements cannot be made. So ICAO standards describe newly-manufactured engines as “* * * engines of a type or model for which the date of manufacture of the first individual production model was after. * * *” the effective date of the applicable standards, and “* * * for which the date of manufacture of the individual engine was on or before. * * *” a specific date that is later than the first effective date of the standards. See ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 4 effective on July 20, 2008. Copies of this document can be obtained from the ICAO Web site at www.icao.int. Five other regulatory features are being established in this final rule. First, we are revising provisions for certain time-limited flexibilities, i.e., potential exemptions, for newly-manufactured engines that may not be able to comply with the first tier of the new NO X standards because of specific technical or economic reasons. 63 Second, we are defining “derivative engine” for emissions certification purposes. The intent of this definition is to distinguish when the emission characteristics of a new turbofan engine model vary substantially from its existing parent engine design, and must show compliance with the emission standards for a newly-certificated engine. Third, we are establishing new CO and NO X standards for turbofan engines that are used to propel supersonic aircraft. These standards were adopted by ICAO in the 1980s, but were not previously added to our HC emission standard for these engines. Promulgating these standards meets our treaty obligation under the Convention on International Civil Aviation as previously described in section I.C. Fourth, we are making several changes to the emission testing and measurement procedures in our regulations that are intended to implement ICAO's Annex 16 and to incorporate the entire annex in our regulations by reference. Finally, as described in section IV, we are amending the current regulatory provisions that address definitions, acronyms and abbreviations, general applicability and requirements, exemptions, and incorporation by reference. These amendments are intended to clarify requirements, make them more consistent with other parts of the program, update the text to be consistent with current standard language conventions, or remove obsolete provisions. 63 These apply only to the first tier of NO X standards. We are not adopting a production cutoff for the second tier of standards. As discussed further below, with the exception of the annual reporting requirement described in section III.D, the amendments reflect those changes that were previously adopted by ICAO. This final rule also is consistent with our authority and obligations under the CAA as described in section I.B. More specifically, the technical feasibility and cost of the emission standards were well documented by our own analyses and CAEP as described later in this section and in section V, Technical Feasibility, Costs, and Emission Benefits. We think that the final rule provides adequate lead time for the development and application of the requisite technology with appropriate consideration to the cost of compliance. We have consulted with the Department of Transportation through the FAA regarding lead time, noise, safety, and the technical feasibility of the new standards. Today's final rule is also consistent with U.S. treaty obligations under the Chicago Convention as described in section I.C., because the requirements are consistent with current ICAO standards. Except to the extent needed to make our standards conform to ICAO's standards by making them applicable to both commercial and non-commercial engines, we are not revising exhaust emission standards for HC, CO, or smoke. All engines subject to the new NO X standards would also continue to be subject to the existing HC, CO, and smoke standards. It is worth emphasizing that although we are including these existing HC, CO, and smoke standards in a new section 87.23, which would also contain the new Tier 6 and Tier 8 NO X standards, we are not actually adopting new standards for these three pollutants, since under the current form of part 87 these HC, CO and smoke standards would already continue to apply to new engine types subject to future revised NO X standards. As discussed above, we are adopting a new naming convention in this preamble and the regulatory text to more easily distinguish between the tiers of increasingly more stringent NO X emission standards. This convention is also consistent with the numeric identifier that CAEP uses to differentiate the CAEP work cycle that produces new NO X standards. (The CAEP naming convention is described in section I.E.) As a result, the first tier of NO X standards, which correspond to CAEP/6, are referred to as Tier 6 in the remainder of today's notice. The second tier of standards is referred to as Tier 8, which correspond to CAEP/8. We are also incorporating the new naming convention in the regulations for the existing NO X emission standards, i.e., Tier 0, Tier 2, and Tier 4. There is no material change to the existing NO X standards themselves, except to the extent that when today's final rule becomes effective, the existing NO X standards would be superseded by Tier 6 standards. We acknowledge that this new naming convention is a change from the past practice of not describing aircraft engine emission standards as tiers. However, we believe the new naming scheme is a valuable tool that makes referring to individual NO X standards much easier. It is also similar to the terminology we use for other mobile source sectors that are subject to environmental regulation and for which standards have become more stringent or have otherwise been amended over time. A. NO X Standards for Newly-Certified Engines We are adopting two different tiers of increasingly stringent NO X standards. These standards would apply for all for newly-certified turbofan aircraft engines with maximum rated thrusts greater than 26.7 kN. 64 (See section III.B for a discussion of how these standards apply for newly-manufactured engines that are not considered to be newly certified.) The numerical value of the applicable standard for an individual engine model is defined by the engine's thrust level and pressure ratio. Simply stated, the pressure ratio is the numerical ratio of the air pressure entering the engine to the air pressure at the entrance to the combustor, i.e., after the air has passed through the compressor section of the engine. 65 The new tiers are described separately below. 64 There are no gaseous emission standards, e.g., NO X , for gas turbine engines with maximum rated thrusts equal to or less than 26.7 kN. These engines are, however, subject to smoke and fuel venting standards. 65 The combustor is a chamber where a mixture of fuel and air is burned to form very hot, expanding gases. As these gases move through the combustion chamber, the walls of the combustor are cooled with dilution air to prevent thermal damage. Dilution air is also used to tailor the gas' temperature profile as it exits the combustor so that the final temperatures will not exceed the allowable limit at the turbine inlet. 1. Tier 6 NO X Standards for Newly-Certified Engines This first tier of new standards is equivalent to the CAEP/6 NO X limits that were adopted by ICAO and became internationally applicable after December 31, 2007. Given that aircraft turbofan engines are international commodities, engine manufacturers introduced engine models after that date that demonstrate compliance with these international standards, or are already planning to do so for upcoming engine designs. Based on this, our evaluation of the necessary lead time, and the lack of any comments on this aspect of the proposal, this tier of standards takes effect immediately upon the effective date of this final rule. The basic form of the NO X standards for turbofan engines is different for higher- and lower-rated thrust engines. Higher output engines are defined as having rated thrusts equal to or greater than 89 kN, while lower output engines are defined as having rated thrusts less than 89 kN but greater than 26.7 kN. The new Tier 6 NO X standards for each of these power groupings are described separately below. a. Numerical Emission Limits for Higher Thrust Engines The Tier 6 NO X standards for newly-certified gas turbine engines with rated thrusts more than 89 kN are differentiated by pressure ratio as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 16.72 + (1.4080 * engine pressure ratio) • For engines with a pressure ratio of more than 30 but less than 82.6: g/kN rated output = −1.04 + (2.0 * engine pressure ratio) • For engines with a pressure ratio of 82.6 or more: g/kN rated output = 32 + (1.6 * engine pressure ratio) The new Tier 6 NO X standards for these higher thrust engines are presented in Figure 1 along with the previous EPA NO X standards, which were based on CAEP/4, for comparison. ER18JN12.000 As a matter of convention, the relative stringency from one CAEP standard to another is expressed relative to a pressure ratio of 30, because the percentage reduction is usually inconsistent across all of the possible pressure ratios, which otherwise makes a simple comparison difficult. Using that convention, the Tier 6 standards (CAEP/6) are referred to as being 12 percent more stringent than the existing EPA NO X Tier 4 standards (CAEP/4). The relative stringency can also be illustrated at other pressure ratios. At pressure ratios less than 30 the reductions are also 12 percent. At pressure ratios above 30, however, the percent reduction decreases as the pressure ratio is increased. Based on the figure, the percent reduction for current technology engines ranges from about 8 to 12 percent. b. Numerical Emission Limits for Lower Thrust Engines The new Tier 6 NO X standards for newly-certified gas turbine engines with rated thrusts between 26.7 and equal to or less than 89.0 kN are differentiated by both pressure ratio and rated thrust as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 38.5486 + (1.6823 * engine pressure ratio) − (0.2453 * kN rated thrust) − (0.00308 * engine pressure ratio * kN rated thrust) • For engines with a pressure ratio of more than 30 but less than 82.6: g/kN rated output = 46.1600 + (1.4286 * engine pressure ratio) − (0.5303 * kN rated thrust) + (0.00642 * engine pressure ratio * kN rated thrust) In developing the corresponding NO X standards for lower thrust engines, CAEP recognized the technical challenges that physically smaller-sized engines sometimes present relative to incorporating some of the lowest NO X technology approaches, which are otherwise available to their larger counterparts. These technical difficulties are well documented and increase progressively as size is reduced (from around 89 kN). 66 For example, the relatively small combustor space and section height of these engines creates constraints on the use of low NO X fuel-staged combustor concepts which inherently require the availability of greater flow path cross-sectional area than conventional combustors. Also, fuel-staged combustors need more fuel injectors, and this need is not compatible with the relatively smaller total fuel flows of lower thrust engines. (Reductions in fuel flow per nozzle are difficult to attain without having clogging problems due to the small sizes of the fuel metering ports.) In addition, lower thrust engine combustors have an inherently greater liner surface-to-combustion volume ratio, and this requires increased wall cooling air flow. Thus, less air will be available to obtain acceptable turbine inlet temperature distribution and for emissions control. 67 With these technological constraints in mind, CAEP fashioned the CAEP/6 NO X standards across the range of thrusts represented by low-thrust engines to become comparatively less stringent, i.e., CAEP/6 relative to CAEP/4, as the rated output and physical size of the engines decrease. We agree with this approach. 66 ICAO/CAEP, “Report of Third Meeting, Montreal, Quebec, December 5-15, 1995,” Document 9675, CAEP/3. A copy of this paper can be found in Docket EPA-HQ-OAR-2010-0687. 67 ICAO, “Combined Report of the Certification and Technology Subgroups,” section 2.3.6.1, CAEP Working Group 3 (Emissions). Presented by the Chairman of the Technology Subgroup, Third Meeting, Bonn, Germany, June 1995. A copy of this paper can be found in Docket EPA-HQ-OAR-2010-0687. As mentioned, the new Tier 6 standards depend on an individual engine's rated thrust and pressure ratio. With two variables in the calculation, the standards cannot be represented in a simple figure, i.e., no single line graph showing the standards for all engines within the thrust range is possible as it was for higher thrust engines. Regardless of this complexity, however, some general observations are useful to characterize the Tier 6 NO X standards for lower thrust engines based on the engine size versus technological challenge described in the previous paragraph. Comparing the new lower and higher thrust standards at 89 kN, which is the demarcation point between the two sets of standards, shows that the standards for lower thrust engines are numerically equivalent to the limit for higher thrust engines at each pressure ratio. This is as expected because the engine sizes and ability to incorporate low-NO X technologies are the same at 89.0 kN delineation point. Again focusing only on 89 kN engines, the new Tier 6 standards represent a 12 percent reduction from the existing EPA Tier 4 (CAEP/4 based standards) for pressure ratios of 30 or less as shown below in Figure 2. This includes the region represented by almost all current engine designs. At higher pressure ratios, the relative numerical reduction is progressively less because the slope of the two standards is essentially the same. ER18JN12.001 At other thrust ratings the percent reduction between the new Tier 6 and existing EPA NO X standards at any pressure ratio becomes progressively smaller as thrust decreases. This is illustrated in Figure 3 for a pressure ratio of 30. This pressure ratio was chosen for the example because, as before, the relative stringency of CAEP NO X standards is generally compared at this point as a matter of convention. As shown in the figure for current engines, the reduction ranges from 12 percent at the upper end of the thrust range to 0 percent at the lower end of the range. The pattern is similar for the other pressure ratios. Only the actual numerical value for percentage reduction at 89 kN, as shown on the far right of the figure, may vary by pressure ratio, as described at the beginning of this paragraph. However, in the region of pressure ratios represented by today's engines, the results are identical to those shown in the figure, i.e., a 12 percent reduction at 89 kN decreasing to 0 percent at 26.7 kN. ER18JN12.002 2. Tier 8 NO X Standards for Newly-Certified Engines The second tier of new standards, i.e., Tier 8, are equivalent to the NO X limits that were most recently recommended at CAEP/8 in February 2010 for adoption by ICAO. 68 The CAEP/8 recommended standards have a recommended applicable date after December 31, 2013. As discussed further in section V of today's notice, we agree with CAEP that this provides engine manufacturers with adequate lead time to respond to these more stringent NO X standards considering the technical feasibility and cost associated with the requirements. 69 Therefore, this tier of standards takes effect on January 1, 2014. As with the new Tier 6 NO X standards, the basic form of the new Tier 8 standards for turbofan engines is different for higher- and lower-rated thrust engines. Higher output engines are defined as having rated thrusts equal to or greater than 89 kN, while lower output engines are defined as having rated thrusts less than 89 kN but greater than 26.7 kN. The longer-term standards for each of these power grouping are described separately below. 68 CAEP/7 did not adopt new aircraft engine NO X standards. 69 Leadtime in this context refers to the time between CAEP adoption of a new emission standard and the effective date of the requirement. ICAO emission standards are global in nature and designed to provide engine manufacturers with adequate time to develop and deploy the requisite technology. Manufacturers produce engines that comply with new ICAO standards to ensure their products can be sold and used worldwide even in the absence of specific U.S. regulations. Based on this response to the ICAO standard, we find that there is also adequate leadtime between EPA's promulgation of the new requirement and the associated effective date. No public comments pertaining to leadtime were received. a. Numerical Emission Limits for Higher Thrust Engines The new Tier 8 NO X standards for newly-certified turbofan engines with rated thrusts of 89 N or more are differentiated by pressure ratio as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 7.88 + (1.4080 * engine pressure ratio) • For engines with a pressure ratio of more than 30 but less than 104.7: g/kN rated output = −9.88 + (2.0 * engine pressure ratio) • For engines with a pressure ratio of 104.7 or more: g/kN rated output = 32 + (1.6 * engine pressure ratio) The new Tier 8 NO X standards for these higher thrust engines are presented in Figure 4 along with the new Tier 6 standards for comparison. ER18JN12.003 As noted previously, as a matter of convention the relative stringency from one CAEP standard to another is generally expressed relative to a pressure ratio of 30. Using that convention, the new Tier 8 standards (CAEP/8) are referred to as being 15 percent more stringent than the new Tier 6 NO X standards (CAEP/6). The relative stringency can also be illustrated at other pressure ratios. At pressure ratios less than 30 the reductions increase. At pressure ratios above 30, however, the percent reduction decreases. Based on the figure, the percent reduction for current engine designs range from about 11 to 19 percent. b. Numerical Emission Limits for Lower Thrust Engines The new Tier 8 NO X standards for newly-certified gas turbine engines with rated thrusts between 26.7 but less than or equal to 89.0 kN are differentiated by both pressure ratio and rated thrust as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 40.052 + (1.5681 * engine pressure ratio) − (0.3615 * kN rated thrust) − (0.0018 * engine pressure ratio * kN rated thrust) • For engines with a pressure ratio of more than 30 but less than 104.7: g/kN rated output = 41.9435 + (1.505 * engine pressure ratio) − (0.55823 * kN rated thrust) + (0.005562 * engine pressure ratio * kN rated thrust) In developing the corresponding CAEP/8 NO X standards for low thrust engines, CAEP recognized the technical challenges that physically smaller-sized engines represent relative to incorporating some of the lowest NO X technology, which is otherwise available to their larger counterparts. These technical difficulties were described in the previous section for the Tier 6 low-thrust engine standards. Also as previously described, no single line graph showing the standards for all engines within the thrust range is possible as it was for higher thrust engines, because the equations have two variables. However, some general observations are useful to characterize the new Tier 8 NO X standards for lower thrust engines based on the engine size versus technological challenge described in the previous paragraph. First, the new Tier 8 NO X standards for lower thrust engines are numerically equivalent to the limit for higher thrust engines across all pressure ratios at the highest rating of 89 kN, where the engine sizes and ability to incorporated low-NO X technologies are comparable. This same characteristic was observed for the Tier 6 standards. Second, as shown below in Figure 5 for 89 kN engines, at this thrust rating the new Tier 8 standards represents a 15 percent reduction from the Tier 6 standards for a pressure ratio of 30. However, within the region of pressure ratios for all current engine designs, the reductions range from 19 to 23 percent. ER18JN12.004 Third, at other thrust ratings the percent reduction between the new Tier 6 and Tier 8 standards at any pressure ratio becomes progressively smaller as thrust decreases. This is illustrated in Figure 6 for a pressure ratio of 30, following the convention described above. Also as shown in the figure for current engines, the reduction ranges from 15 percent at the upper end of the thrust range to 5 percent at the lower end of the range. While not depicted in a figure, the pattern is similar for the other pressure ratios. However, the actual numerical values for percentage reductions at both ends of the thrust range, i.e., 26.7 to 89 kN, may vary by pressure ratio. In the region of pressure ratios represented by today's engines, the results are identical to those shown in Figure 6 at 26.7 kN, i.e., a 5 percent reduction at all pressure ratios for that thrust rating. However, percent reductions increase linearly up to a maximum 23 percent reduction for 89 kN engines with pressure ratios of about 15. ER18JN12.005 B. Application of the Tier 6 NO X Standards to Newly-Manufactured Engines This section describes the application of the new Tier 6 NO X standards to newly-manufactured engines, and our amended temporary flexibilities for newly-manufactured engines that show significant problems complying with these requirements. Also, consistent with CAEP/8, we are not applying the new Tier 8 NO X standards to newly-manufactured engines at this time. This section concludes with a description of future efforts to examine such a possibility. 1. Phase-In of the Tier 6 NO X Standards for Newly-Manufactured Engines As described above, the new Tier 6 NO X standards apply to all engine types or models that receive a new type certificate after the effective date of the final rule. We are also phasing in these same NO X limits for newly-manufactured engines for engine models (and their derivatives for emissions certification purposes) that were originally certified to less stringent requirements (i.e., Tier 2 or Tier 4) and were already being produced for installation on new aircraft prior to the effective date of the final rule. 70 As a result, manufacturers need to bring newly-manufactured engines of these previously certified models into compliance with the applicable Tier 6 standards by a future date or cease production of those engine models. 71 As we discussed and described in our analysis of the need for a CAEP/6 production cutoff during the CAEP process, establishing a date certain for compliance with any emission standard is necessary to ensure that the full benefits of newer, more stringent requirements will be achieved in a reasonable time. 72 We are, however, adopting certain limited flexibilities for engines that cannot be made compliant because of specific technical or economic reasons, as discussed later in this section. 70 The requirement that newly-manufactured engines must meet the CAEP 6 NO X standard by a date certain applies only to engines that are intended to be installed on all new airframes. It would not apply to engines produced as “spares,” which are intended to be installed on existing airframes as replacements for maintenance or other reasons. See section III.B.2 for more information about new and spare engines. 71 After this date the production of any noncompliant engines would cease because the FAA would discontinue issuing an airworthiness approval tag (FAA Form 8130-3) to these engines. 72 ICAO, Committee on Aviation Environmental Protection (CAEP), Eight Meeting, Montreal, 1 to 12 February 2010, Agenda 2: Review of Technical Proposals Relating to Aircraft Engine Emissions, Adoption of Production Cutoff for Emission Standards, WP/56, Presented by the United States, December 12, 2009. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. As described in the proposal, the effective date of January 1, 2013 73 for the newly-manufactured engine standards is consistent with the expected market demand for these previously certified engine types. Historically, engine manufacturers have often responded to the adoption of more stringent NO X standards by bringing older engine types into compliance with the newer requirements well before the required date in anticipation of the likely market demand, or planning for the orderly withdrawal of these engines from the marketplace. Information developed during the ICAO process in 2008 and 2009 74 75 76 and our more recent discussions with manufacturers indicate that: (1) All but a few models are already compliant with CAEP/6 standards, (2) nearly without exception, all current production models will meet the CAEP/6 requirements by the 2012 time frame, and (3) any noncompliant models will be phased out of production because of low market demand. 73 The regulatory text specifies that engine models certified at or below the Tier 4 NO X standards may be produced through December 31, 2012 without meeting the Tier 6 NO X standards. Therefore, the effective date of the standards for newly-manufactured engines is effectively January 1, 2013. 74 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 2009, Agenda 6: Emissions Technical-WG3, Production Cutoffs and Associated Flexibilities for ICAO Engine Emission Standards, WP/39, Presented by U.S. Representative, August 6, 2009. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. 75 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 2009, Agenda Item 3: Forecasting and Economic Analysis Support Group (FESG), CAEP/6 NO X Production Cutoff Cost Analysis, WP/39, Presented by the FESG NO X Stringency Task Group, February 6, 2009. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. 76 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Seattle, 22 to 26 September 2008, Agenda Item 3: Forecasting and Economic Analysis Support Group (FESG), Production Cutoff for NO X Standards, WP/6, Presented by the FESG Rapporteurs, April 9, 2008. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. We think that the five-year phase-in period from ICAO's effective date of the CAEP/6 standards (corresponding to our new Tier 6 NO X standards) for newly-manufactured engines is adequate for manufacturers and their customers to respond to the new requirements without disrupting their future planning and purchasing decisions. 77 78 This phase-in period for applying the Tier 6 NO X standards to newly-manufactured engines is also identical to the date for this same requirement that was adopted by ICAO. No comments were received expressing concern with this phase-in period for newly-manufactured engines. 77 The ICAO CAEP/6 NO X standards became effective after December 31, 2007. 78 This period of time is also consistent with the phase-in period associated with previous ICAO standards. CAEP's predecessor, the Committee on Aircraft Engines Emissions, established the first international emission standards with an effective date four years after adoption, i.e., effectively a four year phase-in. CAEP2 included a phase-in period of 4 years for newly-manufactured engines. We did, however, receive two comments expressing the view that the time between the date of our final rule and the January 1, 2013 effective date of the production cutoff would be too short if it is less than one year. General Electric Aviation (GE) was the most detailed and began by noting that most of the engine models currently in production were certified to the Tier 4 standards and had demonstrated NO X emissions below the Tier 6 at that time. They continued that if the original certification reports are sufficient for the FAA to formally certify these engines to the Tier 6 standards, then none of these engines would be adversely affected by the production cutoff. However, GE expressed the concern that if additional interactions or formal action by the FAA were needed, or revisions to the FAA's FAR Part 34 were required, then having less than one year between EPA's final rule and the production cutoff could disrupt current engine production. As a result, GE asked that the date of the production cutoff be delayed to take effect 12 months after the final rule, i.e., 2013. The other joint comment from the Aerospace Industries Association (AIA) and the General Aviation Manufacturers Association (GAMA) was similar in nature, but without supporting details. The commenters' concerns do not relate to the technical or economic feasibility of newly-manufactured engines achieving emission levels in compliance with the new Tier 6 standards by the date of the production cutoff as proposed. The concerns expressed do not argue that additional time is necessary “to permit the development and application of the requisite technology” to comply with the standards under CAA section 231(b). Therefore, the date of the Tier 6 production cutoff is appropriate and consistent with the Clean Air Act. Section 232(b) of the Act directly addresses our obligation relative to the effective date of the regulation. Specifically, it says: “Any regulation prescribed under this section (and any revision thereof) shall take effect after such period as the Administrator finds necessary (after consultation with the Secretary of Transportation) to permit the development and application of the requisite technology, giving appropriate consideration to the cost of compliance within such period.” Based on the information provided above, the aircraft engine models described by GE are already capable of complying with the EPA Tier 6 NO X standards using already applied requisite technology, i.e., the cost of applying with has already been borne, as the effective date of the corresponding ICAO CAEP/6 NO X standard has already passed. We do not believe there are any technical feasibility or economic implications arising from the continued application of the requisite technology for those engines to meet the Tier 6 NO X standards. Also, consistent with our most recent previous amendment to the NO X standards, which similarly promulgated the standard at a level that was already being met by aircraft engine manufacturers who were already applying the requisite technology, the effective date does not need to include additional lead time for the development and application of additional technology that would be needed to comply with the standards. See, e.g., 70 FR 69604, 69674-76 (Nov. 17, 2005). As a result, the implementation dates provide more than adequate lead time under the statute. Therefore, because aircraft engine manufacturers are already able to comply with the Tier 6 NO X standard through the continued use of already applied requisite technology, and because the effective date of the corresponding ICAO CAEP/6 NO X standard has already passed (and also based on the assessment described in section V. Technical Feasibility, Cost, and Emission Benefits), we find that the dates provide more than adequate lead time under the statute for application of requisite technology. We also want to stress that the production cutoff is actually an ICAO standard and we think it is important to stay aligned with the CAEP production cutoff date. We note that this is also being adopted by the European Aviation Safety Agency (EASA) and perhaps other aviation certification authorities. Our adoption of the proposed date insures international consistency regarding the production cutoff date and avoids contradicting our international bilateral agreements with other governments, e.g., the European Union. Regarding the need for engine models to be formally recognized by the FAA as complying with the new Tier 6 standard, this is completely within the purview of the FAA. In our previous most recent amendment to the NO X standard, we provided just a one-month lead time period before the revised standard became effective, and FAA did not adopt corresponding implementing regulations until one year later, with no apparent disruption to the industry. (See 70 FR 69664, Nov. 17, 2005.) The new Tier 6 standards are the same as the CAEP/6 standards that were approved by ICAO in 2005 with an effective date of beginning after December 31, 2007. Therefore, just as for the 2005 revised NO X standard that we similarly promulgated significantly later than the effective date of the corresponding ICAO CAEP standard, we do not believe that it is necessary to delay the effective date based on a need for the FAA to revise its own implementation and enforcement regulations. Finally, section 232(a) of the Act directs the FAA to ensure compliance with our standards. In this regard, the FAA has developed a streamlined process to recognize compliance with Tier 6 and or Tier 8 as appropriate for currently type certified engine models which meet the emission standards and they have assured the regulated industry that they will dedicate the necessary resources to formally recognize conformance with the standards before the production cutoff date. For the reasons stated above, EPA is promulgating the Tier 6 production cutoff with the originally proposed effective date of January 1, 2013. 2. Carryover of Previously Generated Emission Test Data Aircraft engine models normally receive type certificates, which include a determination that the model meets the emission standards in force at the time the type certificate is granted. EPA has not updated its aircraft emission standards or test procedure regulations since 2005. In this action we are adopting Tier 6 and Tier 8 NO X emission standards and are adopting either in 40 CFR part 87 directly or through incorporation by reference of Annex 16, Volume II a number of minor changes to test procedures and related requirements. These changes will become effective on the date when the rule becomes effective. This leaves open a question regarding the future validity and acceptability for amended type certificates of emission tests and emission test data generated under previously specified test procedures and related requirements. For example, there may be an engine model tested in 2004 that demonstrated HC, CO, and NO X emission levels below the exhaust emission standards in effect at that time and also below the Tier 6 or perhaps even the Tier 8 standards that are being promulgated in this final rule. We want to be clear that we do not intend minor changes to test procedures or related provisions and requirements to trigger the need for additional testing. Thus, in cases where a manufacturer has a valid current type certificate based on emissions information generated under the test procedures in force at the time the type certificate was granted, we consider that data to be valid for any formal FAA recognition of compliance, e.g., an amended type certificate, with the Tier 6 or Tier 8 NO X emission requirements if the original test data demonstrate such compliance. The same is true for the HC and CO emission standards. This clarification should greatly facilitate compliance determinations by the FAA and eliminate any uncertainty regarding the potential for otherwise minor test procedure changes to trigger new emissions testing for previously certificated engines with emission levels below the new NO X standards. 3. Exemptions and Exceptions From the Tier 6 Production Cutoff In conjunction with the implementation of the new Tier 6 NO X standards, we are establishing provisions which allow engine manufacturers to request an exemption or exception from meeting the Tier 6 NO X standards for newly-manufactured engines. These provisions replace existing provisions addressing exemptions that were promulgated in section 87.7 of our aircraft engine regulations. (Any exemptions previously issued under section 87.7 would not be affected by the revisions.) This section of the preamble describes these exemption and exception provisions, i.e., exemptions for engines installed in new aircraft and exceptions for spare engines used in existing aircraft for maintenance purposes. It also includes a description of a short-term exception program (termed the low-volume, time-limited transitional exemption program). These provisions have largely been crafted to be consistent with exemption provisions in the ICAO Environmental Technical Manual (ETM). 79 80 The provisions of the ETM guidance were developed in the context of the CAEP/6 NO X production cutoff deliberations leading up to the CAEP/8 meeting in February 2010. 79 ICAO, “Committee on Aviation Environmental Protection (CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 2010,” CAEP/8-WP/80. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. 80 Note that EPA has submitted a paper to amend the exemption provisions included in this ETM to be consistent with this rule. See ICAO, “Newly Produced Engine Exemptions for CAEP/6 NO X Production Cutoff,” CAEP9_WG3-CTG-2_IP01, September 23, 2010. A copy of this document is in docket number EPA-HQ-OAR-2010-0687. While we are revising our regulations, the process for evaluating any request for an exemption, i.e., petition, and any final decision on its disposition would be unchanged. In this regard, the FAA is the process owner under its enforcement authority contained in section 232 of the Clean Air Act. 81 The FAA must consult with EPA in evaluating the merits of the request, and the EPA must formally concur with any decision regarding the granting or denial of the request. 81 EPA formally transferred the responsibility and authority for the evaluation of requests for exemptions from the emission standards to the Secretary of Transportation (DOT). See “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Final Rule, 47 FR 58462, December 30, 1982. We are deleting from our regulations the requirement in § 87.7(e) that the FAA publish a notice of the exemption in the Federal Register . The FAA has an established process in place for publishing requests for exemption that are filed in accordance with 14 CFR part 11. Under § 87.7(b) of the existing regulations, the FAA, with EPA concurrence, may also exempt low-production volume engines from being fully compliant with the emission standards. Several such short-term exemptions were granted in the 1980s when emission standards were first applied. These exemptions have since expired, and requests for new exemptions under those provisions have not been submitted. We have determined that these provisions, which were adopted in conjunction with revised emission standards in 1982, are no longer of any utility. 82 Therefore, we are deleting these provisions to avoid confusion. 82 U.S.EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures,” Final Rule, 47 FR 58462, December 30, 1982. We are also deleting the time-limited exemption provision for in-use engines that is contained in section 87.7(d) of the existing regulations. This provision applies to fuel venting and smoke emission standards, which were new when the exemption was adopted in 1973. The exemption allowance was limited to in-use engines that were unable to comply with the requirements when the regulation became effective in 1974. The in-use fleet of engines was fully retrofitted to comply with the standards later in the 1970s. Therefore, this provision is now obsolete and we are deleting it to avoid confusion. We proposed to delete the existing provisions for temporary exemptions based on flights for short durations and infrequent intervals. This proposal was based on the EPA's and FAA's belief that the provisions were unnecessary because our standards apply to aircraft certificated by the FAA, and the FAA does not address in the certification process whether an aircraft will be used for short durations or infrequent intervals. Hence, the provisions appeared to have no utility. We received two comments from the Aerospace Industries Association (AIA) and the General Aviation Manufacturers Association (GAMA) requesting that the provision be retained. First, they argued that as in the past, a new aircraft may be produced at a commercial facility that is destined for immediate conversion to a military only application at a separate facility. These aircraft may require a small number of airworthiness flight tests before being delivered to the conversion facility and conceivably would be subject to EPA standards during flight testing. While these aircraft would generally utilize compliant engines, it may be possible that non-compliant engines could be used (our standards do not apply to engines used on military aircraft as discussed later) and temporary exemptions would be necessary. Second, AIA and GAMA commented that it would be helpful if the provision also allowed for granting a discrete number of exemptions over a specified time period, rather than having to request the exemption prior to each flight as currently required. In considering the commenters' suggestion to retain the exemption provision, we note that allowing such operations will not have any significant adverse affect on the environment because of the infrequent nature and short duration of such flights. Retaining the exemption is also consistent with exempting military aircraft from emission control requirements as discussed later. Therefore, we have retained the provision with one change, made in response to the comments, as described below. The current provision calls for the Secretary of Transportation to consult with the EPA Administrator when considering any exemption request for infrequent interval and short duration flights not explicitly allowed by the regulations. Given the inconsequential nature of such flights on the environment, we believe that the Secretary should be able to consider and act on these petitions unilaterally to streamline the process. Therefore, we are deleting that portion of the previous exemption provision. Of course, we will consult with the Secretary if asked to do so. As for requesting a discrete number of temporary exemptions, we believe this is an issue that the Secretary of Transportation may address under its enforcement role as described in section 232 of the CAA. The current regulations also provide for permanent exemptions for newly-manufactured engines based on consideration of the certain factors specified in section 87.7(c). We are replacing these provisions with new regulatory text generally consistent with the ETM that would provide for permanent exemptions or exceptions 83 for newly manufactured engines used on new aircraft and spare engines used for maintenance or replacement purposes. These are summarized below. (See § 87.50 of the regulations for additional details on these exemptions/exceptions.) 83 As used in 40 CFR part 87, as a practical matter the meanings of “exception” and “exemption” are essentially equivalent. However, under FAA regulations, the meanings of these terms are distinct, especially with respect to the manner in which they are administered. a. New Provisions for Spare Engines We are revising the regulations to allow the sale of a newly-manufactured engine for installation on an in-service aircraft, i.e., a spare engine that does not conform to the applicable emissions standards at the time it was produced. It does not allow for installing such an engine on a new aircraft. Spare engines are produced from time to time in order to keep an aircraft in revenue service when the existing in-service engine must be removed for maintenance or replacement purposes as needed. Otherwise removing these aircraft from active service would be very expensive and logistically difficult. As we explained in the proposal, explicitly allowing for the production of spare engines is not addressed in the existing regulations because there is no production cutoff for the current Tier 4 NO X standards. Thus manufacturers have been allowed to continue production of older engine designs under type certificates first issued before the Tier 4 standards took effect (e.g., Tier 2). However, final regulations now apply a Tier 6 NO X production cutoff to all newly- manufactured engines. This means that if we did not also adopt a provision for the continued production of spare engines, manufacturers would be prohibited from producing Tier 4 engines under the existing type certificates for this purpose. We see no reason to change our policy of allowing manufacturers to produce new engines for use as spares. Therefore, the final regulatory provisions allow this practice to continue. To ensure there would be no adverse environmental effect from allowing the use of a spare engine as a direct replacement for an existing engine, we proposed that the spare could be used only when the emissions for all pollutants of that engine were equal to or lower than those of the engine it replaced. This proposed requirement was consistent with the ETM, which also contains this allowance. We received a joint comment from AIA and GAMA stating that this is impractical because, while unlikely, a spare engine might have a different emissions profile for some pollutants than the engine it would replace. As an example, they stated that the two engines could have somewhat different combustion systems that might make one engine lower in NO X but higher in CO. They also suggested that EPA should consider the totality of the emissions in the decision, or delete the requirement in the final rule. These comments are surprising because this ETM provision, as well as the exception provisions, was subject to significant discussions within CAEP that included the engine manufacturers as well as a representative from AIA. Nonetheless, in this instance we believe the proposed provision should be modified to accommodate the potential for unusual circumstances as explained by the commenter. As noted above, AIA and GAMA suggested that EPA consider of the totality of emissions relative to their environmental effects as the basis for evaluating spare engine exemptions. This would entail understanding and comparing the environmental consequences of the different pollutants. We find that could be very complicated because different pollutants have different health and welfare end points and consequences. For example, in the illustration offered by the commenters, the effects of LTO NO X and CO are largely unrelated to one another. We think a preferred option to evaluating total environmental effects, or even dropping the provision entirely, is to incorporate an anti-backsliding requirement which ensures that at a minimum the excepted spare engine at least meets the same emission standards that are applicable to the engine it is replacing. For this reason, in response to the AIA and GAMA comment, we are modifying this provision in the final rule to allow an excepted spare engine to have different emission levels compared to the engine it replaces as long as it remains compliant with each of the applicable emission standards and any other requirements of its type certificate. Given the limited number of spare engines in the fleet, we expect allowing these engines to have somewhat different emissions profile from engines they are replacing will have no significant adverse environmental effect. This is especially true given that we expect the emissions of an excepted spare engine will be equal or better than the engine it is replacing in most cases in accordance with the basic tenant of the ETM. We are not requiring engine manufacturers to obtain FAA or EPA approval before producing spare engines. However, they must submit information about the production of spare engines in an annual report to EPA (see section III. D for more on the annual report). We proposed that because manufacturers are not require [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A2012-13828. Public record. Not legal advice.