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Citation: 73 Fed. Reg. 28321 2008

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-- The search text of this PDF is generated from uncorrected OCR text.Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

No comments objecting to the proposal

were received. Class E airspace areas extending from 700 feet or more above the surface ofthe earth are published in paragraphs 6005 ofFAA Order 7400.96, signed August 14, 2007, and effective September 15, 2007, which is incorporated by reference in 14 CFR 71.1.The class airspace designation listed in this document will be published subsequently in the Order.
The Rule

The FAA is amending Title 14, Code ofFederal Regulations (14 CFR)part 71 to modify Class E airspace at Waynesburg, PA, by providing additional controlled airspace for aircraft executing the RNAV (GPS) Runway 09/27 to the Green County Airport. This action also corrects the geographic position coordinates of the airport.

The FAA has determined that this regulation only involves an established body,oftechnical regulations for which frequent and routine amendments are necessary tokeep them operationally current. It, therefore, (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory.Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation ofa Regulatory Evaluation as the anticipated impact is so minimal. Since this is a routine matter that will only affect air traffic procedures and air navigation, it is certified that this rule, when promulgated, will not have a significant economic impact on a substantial number of small entities under the criteria ofthe Regulatory Flexibility Act.

The FAA's authority to issue rules regarding aviation safety is found in the Title 49 of the United States Code. Subtitle I, Section 106 describes the authority ofthe FAA administrator. Subtitle VII, Aviation Programs, describes in more detail the scope.ofthe agehcy's authority.

This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart 1,Section 40103. Under that section, the FAA is charged with prescribing regulations to assign the use ofairspace necessary to

ensure the safety of aircraft and the efficient use of airspace. This regulation is within the scope ofthat authority as it modifies Class E Airspace at Waynesburg, PA.
List of Subjects in 14 CFR Part 71

Airspace, Incorporation by reference, Navigation (air). Adoption ofthe Amendment

mIn consideration ofthe foregoing, the Federal Aviation Administration amends 14-CFR part 71 as follows:

PART 71-DESIGNATION OF CLASS A, -CLASS B, CLASS C, CLASS D,AND CLASS E AIRSPACE AREAS; AIRWAYS; ROUTES; AND REPORTING POINTS

m1. The authority citation forpart 71 continues to read as follows:

Authority: 49 U.S.C. 106(g); 40103, 40113, 40120; E.O. 10854, 24 FR 9565, 3 CFR, 1959- 1963 Comp., p. 389.
§71.1 [Amended]

a 2. The incorporation by reference-in 14 CFR 71.1 ofFederal Aviation Administration Order 7400.9R, Airspace Designations and Reporting Points, signed August 15, 2007, and effective September 15, 2007, is amended as follows: Paragraph 6005 ClassEAirspaceAreas Extending Upward from 700 feet orMore Above theSurface oftheEarth.

AEA PA E5 Waynesburg, PA [Revised] Green County Airport, PA

(Lat. 39°54'04" N., long. 80°07'51"W.) That airspace extending upward from 700 feet above the surface ofthe Earth within an 8.3-mile radius ofGreen County Airport.

Issued in College Park, Georgia, on April 21, 2008. Lynda G. Otting, ActingManager, System SupportGroup, EasternService Center, AirTraffic Organization. [FR Doc. E8-10425 Filed 5-15-08; 8:45 am]

BILLING CODE 4910-13-M

DEPARTMENT OF HOMELAND

SECURITY

Coast Guard

33 CFR Part 165 [Docket No. USCG-2008-0366] Security Zone; Portland Rose Festival
on Willamette River

- •
AGENCY: Coast Guard, DHS. ACTION: Notice .ofenforcement of regulation.
SUMMARY: The Coast Guard will enforce the Portland Rose Festival Security Zone onthe Willamette River from 1

a.m. onJune 4, 2008 until 10 a.m. June 10, 2008. This action is necessary for the security ofpublic vessels on a portion ofthe Willamette River during the fleet week ofthe Rose Festival. This security

zone provides forthe regulation of vessel traffic in the vicinity ofthe moored public vessels. During the enforcement period, entry into this zone is prohibited unless authorized by the Captain ofthe Port orhis designee. DATES: The .regulations in 33 CFR 165.1312 will be enforced'commencing from 1 a.m. on June 4, 2008 until 10

a.m. June 10, 2008.

FOR FURTHER INFORMATION CONTACT: MST1 Lucia Mack, Coast Guard Sector Portland, 6767 N. Basin Ave, Portland, OR 97217, telephone 503-240-9311.
SUPPLEMENTARY INFORMATION: The Coast Guard will enforce the Rose Festival Security Zone established by 33 CFR 165.1312 from 1 a.m. on June 4, 2008 until 10 a.m. June 10, 2008.

Under the provisions of33 CFR 165.33 a vessel may not enter the regulated area, unless it receives permission from the Captain ofthe Port

or his designee. The Coast Guard maybe assisted by other Federal, State, or local law enforcement agencies in enforcing this regulation.

This notice is issued under authority of 33 CFR 165.1312 and 5 U.S.C. 552(a). In addition to this notice in the Federal Register, the Coast-Guard willprovide the maritime community with extensive advance notification ofthis enforcement period via the Local Notice to Mariners and marine information broadcasts.

Dated: May 6, 2008. F.G.Myer, Captain,U.S. CoastGuard,Captain ofthe Port, Portland.

. [FR Doc. E8-10921 Filed 5-15-08; 8:45 am]

BILLING CODE 4910-15-P

ENVIRONMENTAL PROTECTION

AGENCY

40 CFR Parts 51 and 52
[EPA-HQ-OAR-2003-0062; FRL-8566-1]

RIN 2060-AN86 Implementation of the New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM 2.5 )
AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule.
SUMMARY: The EPA is finalizing regulations to implement the New Source Review (NSR) program for fine particulate matter (that is, particles with

an aerodynamic diameter less than or equal to a'nominal 2.5 micrometers, 

### 28321

### 28322 Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

generally referred to as "PM 2
.5"). The NSR program was created by the Clean Air Act (Actor CAA) to ensure that stationary sources ofair pollution are constructed or modified ina manner that is consistent with air quality goals in the area.

The Clean Air Fine Particle Implementation Rule, which was proposed in the Federal Register on November 1, 2005, included requirementS'and guidance for State and local air pollution agencies to follow in developing State implementation plans (SIPs) and also the NSR provisions. The final implementation rule that was promulgated on April 25, 2007, included allthe SIPs related provisions. In this rulemaking, EPA is finalizingthe NSR provisions ofthe November 1, 2005 proposed rule including the major
source threshold, significant emissions rate, and offset ratios for PM 2.5, interpollutant trading for offsets and applicability ofNSR to PM 2. 5 precursors. DATES: This final rule is effective on July 15, 2008. ADDRESSES: The EPA has established a docket forthis action under Docket ID No. EPA-HQ-OAR-2003-0062. All documents inthe docket are listed on the www.regulations.govWeb site. Although listed in the index, some information may notbe publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet andwill be publicly available only in hard copy form. Publicly available docket materials are available either electronically through www.regulations.govor in hard copy at the Air Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Avenue, Northwest, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding Jegal 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: Mr. Raghavendra (Raj) Rao, Air Quality Policy Division, Office ofAir Quality Planning and Standards (C504-03), U.S. Environmental Protection Agency, Research Triangle Park, North Carolind 27711, telephone -umber: (919) 541- 5344, facsimile number: (919) 541-5509, e-mail address: rao.raj@epd.gov; or Mr. Dan deRoeck, at the same address, telephone 919-541-5593, or e-mail at deroeck.dan@epa.gov.
SUPPLEMENTARY INFORMATION:

I. General Information

A. Does thisactionapplyto me?
Entities affected by this rule include

sources in all industry groups. The majority of sources potentially affected

are expected to be in the following groups:,
Industry group .NAICSa

Electric services

........................................................................................ 221111, 221112, 221113, 221119, 221121, 221122 Petroleum refining

................................................................................... 32411 Industrial inorganic chemicals

....................................................... I

......... 325181, 32512, 325131, 325182, 211112, 325998, 331311, 325188 Industrial organic chemicals

.................................................................... 32511, 325132, 325192, 325188, 325193, 32512, 325199 Miscellaneous chemical products

............................................................ 32552, 32592, 32591, 325182, 32551 Natural gas liquids

................................................................................... 211112 Natural gas transport

................................................................................ 48621, 22121 Pulp and paper mills

................................................................................. 32211, 322121,322122, 32213 Paper mills

................................................................................................ 322121, 322122 Automobile manufacturing

........................................................................ 336111, 336112, 336712, 336211, 336992, 336322, 336312, 33633, 33634,33635,336399,336212,336213 Pharmaceuticals

....................................................................................... 325411, 325412, 325413, 325414

aNorth American Industry Classification System.

Entities affected by this rule also include States, local reviewing authorities, and Indian country with

new and modified major stationary
sources.
B. Where canI geta copy ofthis documentandotherrelated information?

In addition to being available in the docket, an electronic copy ofthis final rule will also be available on the World Wide Web. Following signature bythb EPA Administrator, a copy ofthis final rulewill be posted inthe regulations and standards section of our NSR home page located at http://www.epa.gov/nsr.

C.

How is thispreambleorganized?
The information presented,inthis preamble is organized as follows: I.General Information

A. Does this action apply to me? B.Where can I get acopy ofthis document

and other related information? C.How is this preamble organized? II. Purpose III. Background A. New Source Review (NSR) Program B. Fine Particulate Matter and the NAAQS

for PM 2. 5 C. Implementation ofNSR for PM 2.5 IV. Overview ofThis Final Action V. Rationale for Final Actions

A.Applicability of NSR to Precursors uf

PM 2.5 in the Ambient Air 1.What is EPA's legal authority to regulate

precursors? 2.What is EPA's approach for addressing

precursors? 3.Final Action on SO 2 4. Final Action on NOx 5. Final Action on VOC 6. Final Action on Ammonia B. Major Stationary Source Threshold for

PM 2. 5 C. Significant Emissions Rate for Direct

Emissions of PM 2. 5 D. Significant Emissions Rates for PM 2.5

Precursors E.Condensable PM Emissions F. Prevention of Significant Deterioration

(PSD) Program Requirements 1.How must BACT be implemented for

PM 2.s? 2. How does EPA plan to address PM 2.5 Increments, Significant Impact Levels (SILs), and Significant Monitoring Concentiations (SMCs)? 3. What is the ambient air quality analysis

requirement for PM 2. 5? 4. How must the PSD preconstruction

monitoring requirement be implemented for PM 2. 5 ? G. Nonattainment New Source Review (NA

NSR) Requirements 1.

What is the required offset ratio for direct PM 2. 5 emissions? 2. Which precursors are subject to the

offset requirement? 3.

What is the required offset ratio for PM 2_5 precursors? 4.Is interpollutant trading allowable to

comply with offset requirements? H. How will the transition to the PM 2. 5 PSD requirements occur? 1.

Background 2.

Transition for "Delegated States" 3. Transition for "SIP-Approved States" I. How will the transition to thdPM2. 5 NA NSR requirements occur? 1.Background 2.Transition

### Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

3. Implementation of NSR Under the

"Emissions Offset Interpretative Ruling" (40 CFR -part51, appendix S) with Revisions J. Does major NSR apply to PM 2.5

precursors during the SIP development period? K. Are there any Tribal concerns? L. What are the requirements for minor

NSR for PM 2. 5? M. Rural Transport Areas VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory

Planning and Review B. Paperwork Reduction Act C. Regulatory Flexibility Act 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 and Safety Risks H. Executive Order 13211-Actions That

Significantly Affect Energy Supply, Distribution, or Use I.National Technology Transfer and

Advancement Act J.Executive Order 12898-Federal Actions

to Address Environmental Justice in Minority Populations and Low-Income Populations K. Congressional Review Act L. Petitions for Judicial Review M. Determination Under Section 307(d) VII. Statutory Authority II. Purpose
The purpose -ofthisrulemaking is to finalize the major NSR program provisions for PM2.5.This final rule supplements the final implementation rule for PM2.5(excluding the NSR provisions) that we 1promulgated on April 25, 2007 at 72 FR 20586. This final action on the bulk ofthe major NSR program for PM2.5along with our proposed rule on increments, SILs, and SMC, when final, will represent the final elements necessary to implement a PM2.5PSD program. When both rules are promulgated and in effect, the PM2.5 PSD program will no longer use a PM1o program as a surrogate, as has been the practice under our existing guidance.

1II.Background

A. New SourceReview (NSR) Program

The existing regulations require both major and minor NSR programs to address any pollutant forwhich there is

a National Ambient Air Quality Standard (NAAQS) and precursors to the formation ofsuch pollutant when identified forregulation by the Administrator. This final rule amends the NSR regulations to establish the minimum elements for State, local, and Tribal agency programs implementing NSR for the PM 2.5NAAQS. This preamble also explains what interim provisions would apply with respect to PM2.5during the State Implementation Plan (SIP) development period.

The NSR program is a preconstruction permitting program that applies when a
source is constructed or modified. The NSR program is composed ofthree different programs:

e Prevention of Significant Deterioration (PSD); " Nonattainment NSR (NA NSR); and " Minor NSR. We often refer to the PSD and NA NSR
programs together as the major NSR program because these programs regulate only major sources. 2

The PSD program applies when a major source that is located in an area that is designated as attainment or unclassifiable for any criteria pollutant is constructed or undergoes amajor modification. 4The NA NSR program applies when a major source that is located in an area that is designated as nonattainment for any criteria pollutant is constructed orundergoes a major modification. The minor NSR program addresses both major and minor sources that undertake construction or modification activities that do not qualify as major, and it applies regardless of the designation ofthe area in which a source is located.

The national regulations that apply to each ofthese programs are located in the Code ofFederal Regulations (CFR)

as shown in the following table:

Program Applicable regulations

PSD

.......................................................................................................... 40 CFR 52.21, 40 CFR 51.166, 40 CFR 51.165(b). NA NSR

.................................................................................................... 40 CFR 52.24, 40 CFR 51"165,40 CFR part 51, appendix S. Minor NSR

................................................................................................ 40 CFR 51.160-164.

The PSD requirements include but are not limited to: * Installation ofBest Available Control Technology (BACT); * # Air quality monitoring and modeling analyses to ensurethat a project's emissions will not cause or contribute to a violation ofany NAAQS

or maximum allowable pollutant increase (PSD increment);

• Notification ofFederal Land Manager ofnearby Class I areas; and

• Public comment on the permit. Nonattainment NSR requirements include but are not limited to:.

e Installation ofLowest Achievable Emission Rate (LAER) control technology;

'In this proposal, the terms "we," "us," and "our," refer to the EPA and the terms "you," and "your," refer to the owners or operators of stationary sources of air pollution. o Offsetting new emissions with creditable emissions reductions;

o Certification that all major sources owned and operated in the State by the

same owner are in compliance with all applicable requirements under the Act;

* An alternative siting analysis demonstrating that the benefits of the proposed source significantly outweigh the environmental and social costs imposed as a result of its location, construction, ormodification; and

e Public comment on the permit. Minor NSR programs must meet the statutory requirements in section 110(a)(2)(C) ofthe Act, which requires

.. * * regulation ofthe modification and construction of any stationary

source * * * as necessary to assure that

ZThe Act uses the terms "major emitting facility"
to refer to sources subject to the PSDprogram, and "major stationary source" to refer to sources subject
to NA NSR. SeeCAA sections 165,169,172(c)(5), and 302(j). For ease ofreference, we use the term "major source" to refer toboth terms. national ambient air quality standards

are achieved."

B. Fine Particulate Matterandthe NAAQSforPM2.5

Fine particles in the atmosphere are made up ofa complex mixtur6 of components. Common constituents include sulfate (SO4); nitrate (NO,); ammonium; elemental carbon; a great variety oforganic compounds; and inorganic material (includingmetals, dust, sea salt, and other trace elements) generally referred to as "crustal" material, although it may contain. material from other sources. Airborne particulate matter (PM) with a nominal aerodynamic diameter of2.5. miciometers or less (a micrometer is

3The term "criteria pollutant" means a pollutant for which we have set a NAAQS.

4In addition, the PSD program applies to most noncriteria regulated pollutants. 

### I 28323Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

one-millionth ofa meter, and 2.5 micrometers is less than one-seventh the average width of ahuman hair) are considered to be "fine particles," and

are also known as PM2.5. "Primary" particles are emitted directly into the air

as a solid or liquid particle (e.g., elemental carbon from diesel engines or fire activities, or condensable organic particles from gasoline engines). "Secondary".particles (e~g., sulfate and nitrate) form ip the atmosphere as a result ofvarious chemical reactions.

The health effects associated with exposure to PM 2. 5 are significant. Epidemiological studies have shown a significant correlation between elevated PM2.5 levels and premature mortality. Other important effects associated With PM2.5 exposure include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school orwork, and restricted activity days), lung disease, decreased lung function, asthma attacks, and certain cardiovascular problems. Individuals particularly sensitive to PM2. 5 exposure include older adults, people-with heart and lung disease, and children.

On July 18, 1997, we revised the NAAQS forPM to add new standards for fine particles, using PM2.5 as the indicator. We established health-based (primary) annual and 24-hour standards for PM2.5 (62 FR 38652). We set an annual standard at a level of 15 micrograms per cubic meter (gg/m 3) and

a 24-hour standard at a level of 65 gg/ M 3

. At the time we established the primary standards in 1997, we also established welfare-based (secondary) standards identical to the primary standards. The secondary standards are designed to protect against major environmental effects ofPM2. 5 such as visibility impairment, soiling, and materials damage.

On October 17, 2006, we revised the primary and secondary NAAQS for PM2:5 and PM1o. In that rulemaking, we reduced the 24-hour NAAQS for PM2.5 to 35 gg/m 3 and retained the existing annual PM2.5 NAAQS of 15 gg/m3. In addition, we retained PMo as the indicator for coarse PM, retained the existing PM1o24-hour NAAQS of 150 jg/m 3

, and revoked the annual PM10 NAAQS (which had previously been set at 50 gg/m3). See 71 FR 61236.

5Available in the docket for thisrulemaking, ID No. EPA-HQ-OAR-2003-0062, and at http:// www.epa.gov/regiono7/progroms/artdlair/nsr/ nsrmemos/pm25.pdf. C.Implementationof NSRforPM 2.5 After we promulgated the NAAQS for PM2. 5 in 1997, we issued aguidance document entitled "Interim Implementation forthe New Source Review Requirements forPM 2. 5" (John S. Seitz, EPA, October 23, 1997). 5 As noted in that guidance, section 165 of the Act suggests that PSD requirements become effective for a new NAAQS upon the effective date ofthe NAAQS. Section 165(a)(1) ofthe Act provides that no new or modified major source maybe constructed without aPSD permit that meets all ofthe section 165(a) requirements with respect to the regulated pollutant. Moreover, section 165(a)(3) provides that the emissions from any such source may not cause or contribute to aviolation ofany NAAQS. Also, section 165(a)(4) requires BACT for each pollutant'subject to PSD regulation. The 1997 guidance stated that sources would be allowed to use implementation ofaPM 1oprogram as a surrogate for meeting PM2. 5 NSR requirements until certain difficulties

were resolved, primarily the lack of necessary tools to calculate the emissions of PM 2 .5 and related precursors, the lack ofadequate modeling techniques to project ambient impacts, and the lack ofPM2.5 monitoring sites.

On April 5, 2005, we issued a guidance document entitled "Implementation ofNew Source Review Requirements in PM-2.5 Nonattainment Areas" (StephenD. Page, EPA). 6 This memorandum provides guidance on the implementation ofthe nonattainment major NSR provisions in PM2.5 nonattainment areas in the interim period between the effective date ofthe PM2. 5 NAAQS designations (April 5, 2005) and the promulgation date ofthe final NSR regulations reflected in this action. Besides affirming the continuation ofthe Seitz guidance

memo in PM 2 .5 attainment areas, the April 5, 2005 memo recommends that until we promulgate thePM2.5major NSR regulations, States should use a PM 10 nonattainment major NSR program
as a surrogate to address the requirements ofnonattainment major NSR for PM2. 5. On November 1, 2005, we proposed a rule to implement the 1997 PM2.5 NAAQS, including proposed revisions to the NSR program (70 FR 65984). As discussed above, this action finalizes the portion ofthat proposal related to

6Available in the docket for this rulemaking, ID.

No. EPA-HQ-OAR-2003-0062, and at http:// www.epa.gov/nsr/documents/nsrnemo.pdf. NSR. The other portions of that proposal, concerning attainment dates, SIP submittals, reasonable further progress (RFP) requirements, etc., were finalized on April 25, 2007 (72 FR 20586).

On September 21, 2007, we proposed additional elements for th% PSD program for PM2. 5 including PM 2. 5 "increments," significant impact levels (SILs), and significant monitoring concentrations (SMCs) (72 FR 54112). Increments are the maximum allowable increases over baseline concentrations that can be permitted to occur when a major source is constructed or modified. This is one mechanism by which the PSD program prevents significant deterioration in air quality. A SIL defines the level ofambient air impact that is considered a "significant contribution" to air quality. Ifthe modeled maximum ambient impacts of

anew source or modification are below the SILs, the source: (1) Is presumed not to cause or contribute significantly to a PSD increment or NAAQS violation, and (2) is not required to perform the multiple-source, cumulative impacts assessments that are otherwise required under PSD. An SMC defines the level of modeled ambient air impact below which the reviewing authority may .exempt a new or modified source from conducting the preconstruction monitoring that may otherwise be required under PSD. The reviewing authority may also exempt the source from preconstruction monitoring ifthe existing monitored ambient concentration is less than the SMC. This final action on the bulk ofthe major NSR program forPM2.5 along with our proposed rule on increments, SILs, and SMC, when final, will represent the final elements necessary to implement a PM 2.5 PSD program. When both rules are promulgated and in effect, the PM2. 5 PSD program will no longer use a PM 10 program as a surrogate, as has been the practice under our existing guidance.
IV. Overview ofThis Final Action

The table below summarizes the main elements ofthe existing NSR program that this action addresses for PM2.5 as a regulated NSR pollutant. The table indicates our final position on an issue and whether our position has changed based on comments received. Our final action for each element, or where appropriate, explanation of implementation under existing 

### 28324Federal Register/Vol. 73, No..96/Friday, May 16, 2008/Rules and Regulations regulations, is addressed in detail in the

referenced sections of this preamble.

NSR program element Final action Section Applicability to PM2 .5 precursors

............. SO-Must be regulated as precursor, NOx-Presumed rejulated, VOC-Pre- V.A

sumed not regulated, Ammonia-Presumed not regulated. PSD major source threshold

................... 100/250 tons per year (tpy)

.................................................................................... V.B NA N SR major source threshold

............ 100 tpy
.................................................................................................................... V.B Significant emissions rate

....................... Direct PM 2.

5 emissions-10 tpy, SO2 precursor--40 tpy, NOx precursor-40 tpy, V.C &V.D if regulated. Condensable PM 2.5 emissions

................ Included in direct PM 2.

5 emissions for major NSR applicability determinations V.E after the end of the transition period (changed based on comments received). Control technology: BACT and LAER

..... Applies for direct PM 2.,emissions, SO 2,and other precursors if regulated. V.F.1 &V.G Prevention of significant deterioration

..... Increments, SILs and SMCs covered ina separate rulemaking

........................... V.F.2 Air quality im pact analysis

...................... Applies for PM2.. ..................................................................................................... V.F.3 Preconstruction monitoring

..................... Applies for PM 2.5 (finalizing options 1&3)

............................................................ V.F.4 NA NSR Statewide compliance and al- Applies for direct PM 2.5 emissions and precursors, if regulated

............................ V.G temative siting analyses. NA NSR offsets

....................................... Applies for direct PM 2.

5 emissions and precursors, if regulated

............................ V.G.1-3 Interpollutant offsetting

............................ Allowed on a regional or statewide basis; EPA is issuing guidance with rec- V.G.4

ommended regional hierarchies and trading ratios (changed based on comments received). Transition for PSD
................................... Continues to use PM 1oas a surrogate

................................................................... V.H Transition for NA NSR

............................ Applies through an approved SIP or through 40 CFR part 51, appendix S

.......... V.1 SIP development period

.......................... Clarifies that major NSR does not apply to precursors during the SIP develop- V.J

ment period inattainment areas (changed based on comments received). Tribal concerns
........................................ Cross references to proposed NSR rules for Indian country

.............................. V.K Minor NSR

............................................... Clarifies that State and local regulatory programs must include PM 2., require- V.L ments for minor sources. NSR transport option

.............................. Transport classification not available

..................................................................... V.M

The provisions of the PM2.5major NSR program finalized in this action are codified as.revisions in the previously existing regulatory text. The revisions to NA NSR are codified in 40 CFR 51.165 and appendix.S to 40 CFR part 51. The PSD revisions are codified in 40 CFR 51.166 and 52.21.

V. Rationale for Final Actions

In this section we discuss each element of our proposal'for this rulemaking, explain our final action, discuss the rationale for our final action, and summarize the major public
comments we received. The full
summary ofpublic comments on the proposal, along with our responses, can be founcrinthe docket for this rulemaking.7

A. Applicabilityof NSR to Precursors of PM 2.5in theAmbientAir
Scientific research has shown that various pollutants can contribute to 'ambient PM 2., concentrations. In additibn to direct PM2.5emissions, these include the following precursors:

" Sulfur dioxide (SO 2); " Oxides of nitrogen (NOx); " Volatile organic compounds (VOC); and

7See "Implementation ofthe New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers in Diameter (PM 2.5); Response to Comments," U.S. Environmental Protection Agency. It can be viewed or downloaded at www.regulations.gov,Docket ID No. EPA-HQOAR-2003-0062. * Ammonia. .These gas-phase precursors undergo chemical reactions in the atmosphere to form secondary PM. Formation of secondary PM depends on numerous factors including the concentrations of precursors; the concentrations ofother gaseous reactive species; atmospheric conditions including solar radiation, temperature, andrelative humidity; and the interactions ofprecursors with preexisting particles and with cloud or fog droplets. Several atmospheric aerosol species, such as ammonium nitrate and certain organic compounds,

are semi-volatile and are found in both gas and particle phases. Given the complexity ofPM formation processes,
new information fromthe scientific community continues to emerge to improve our understanding ofthe relationship between sources ofPM precursors and secondary particle formation.

Precursors contribute significantly to ambient PM2.5 concentrations, producing approximately halfof the concentration nationally. In most areas ofthe country, PM2.5precursor emissions are major contributors to ambient PM2.5concentrations. The relative contribution to ambient PM2. 5 concentrations from each ofthese pollutants varies by area. The relative effect ofreducing emissions ofthese pollutants is also highly variable. Some PM2.5precursors are already subject to major NSR under other NAAQS, as shown in the following table:

PM 25 Existing program coverage precursor for major NSR applicability

NOx

................ NA NSR and PSD for NO 2 and Ozone. SO2

......

. ..... ... NA NSR and PSD for SO2. VOC

............... NA NSR and PSD for Ozone. Ammonia

....... No coverage for NSR.

-

In the subsections that follow, we first discuss our legal authority under the Act forregulating precursors to the formation ofcriteria pollutants, and then discuss our final action for each of the PM2.5precursors. • 1.What is EPA's legal authority to regulate precursors?

As we discussed in the November 1, 2005 proposal, we interpret the Act to not only provide explicit authority for EPA to regulate precursors, but also to grant us discretion to determine how to address precursors for particular regulatory purposes. This reading is based on section 302(g) ofthe Act, which defines the term "air pollutant" to include "any precursors to the formation ofany air pollutant, to the extent the Administrator has identified such precursor or precursors for the particular purpose for which the term 'air pollutant' is used." The first clause ofthis second sentence in section 302(g) explicitly authorizes the Administrator 

### 28325Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

to identify and regulate precursors as air pollutants under other parts ofthe Act. In addition, the second clause ofthe
sentence indicates that the Administrator has discretion to identify which pollutants should be classified as precursors for particular regulatory purposes. Thus, we do not necessarily construe the Act to require that EPA identify a particular precursor as an air pollutant for all regulatory purposes where it can be demonstrated that various programs under the Act address different aspects ofthe air pollutant problem. Likewise, we do not interpret the Act to require that EPA treat all precursors ofa particular pollutant the

same under any one program when there is abasis to distinguish between such precursors within that program. For example, in a recent rule addressing PM2.5 precursors for purposes ofthe transportation conformity program, we chose to adopt a different approach for

one precursor based on the limited emissions of that precursor from onroad mobile sources and the degree to which it contributes to PM2. 5 concentrations (70 FR 24280, May 6, 2005).

Other provisions of the Act reinforce

our reading of section 302(g) to mean that Congress intended precursors to NAAQS pollutants to be subject to the air quality planning and control requirements of'the Act, but also recognized that there may be circumstances where it is not appropriate to subject precursors to certain requirements ofthe Act. Section 182 ofthe Act provides for the regulation of NOx and VOC as precursors to ozone in ozone nonattainment areas, but also provides in section 182(f) that major stationary

sources ofNOx (an ozone precursor) are not subject to emission reduction requirements for ozone where the State shows through modeling that NOx reductions do not decrease ozone. Section 189(e) provides for the regulation ofPM10 precursors in PM10 nonattainment areas, but also recognizes that there may be certain circumstances (e.g., if precursor emission sources do not significantly contribute to PM1o levels) where it is not appropriate to apply control requirements to PM10 precursors. The legislative history of section 189(e) recognized the complexity behind the science of precursor transformation into PM 10 ambient concentrations and the need to harmonize the regulation of PM1o precursors with other provisions ofthe

- Act:

The Committee notes that some ofthese precursors may well be controlled under other provisions ofthe CAA. The Committee intends that * * * the Administrator will develop models, mechanisms, and other methodology to assess the significance ofthe PM1Q precursors inimproving air quality and reducing PM 0 . Additionally, the Administrator should consider the impact on ozone levels ofPM10 precursor controls. The Committee expects the Administrator to harmonize the PM 10 reduction objective of this section with other applicable regulations ofthis CAA regarding PM 0 precursors, such

as NOx. See H. Rpt. 101-490, Pt. 1, at 268 (May 17, 1990), reprinted in S. Prt. 103-38, Vol. II, at 3292.

In summary,section 302(g) ofthe Act clearly calls for the regulation of precursor pollutants, butthe Act also identifies circumstances when it may not be appropriate to regulate precursors and gives the Administrator discretion
to determine how to address particular precursors under various programs required by the Act. Due to the complexities associated with precursor emissions and their variability from location to location, we believe that in certain situations it may notbe effective

or appropriate to control a certain precursor under aparticular regulatory program or forEPA to require similar control ofi particular precursor in all
,;.reas of the country. The term "air pollutant," as defined in section 302(g), is incorporated into the NSR provisions forvarious purposes. Thus, we interpret section 302(g) ofthe Act to require us to consider how to address precursors under the NSR program.

With regard to PSD, section 165(a)(3) ofthe Act states that new or modified major sources must demonstrate that emissions "will not cause, or contribute to, air pollution in excess ofany * * * NAAQS in any air quality control region
* * t." A source could not reasonably make this demonstration without considering precursors that EPA has identified for thispurpose. Section 165(a)(4) ofthe Act states that a new or modified source must apply BACT "for each pollutant subject to regulation under this Act emitted from, or which results from, such facility." The phrase "emitted from, or which results from" indicates that the statute is not limited
to direct emissions, but rather extends to precursors as well.

With regard to NA NSR, sections 172(c)(4) and 173 require States to demonstrate, among other things, that emissions from new or modified major

sources are consistent with the achievement of "reasonable further progress." Reasonable further progress is further defined as reductions ofthe relevant air pollutant, which is defined in section 302(g) to include precursors identified by EPA as subject to regulation for that purpose.
2. What is EPA's approach for addressing precursors?

As proposed, we are finalizing different approaches for addressing the individual precursors to PM2.5 under the Act's NSR provisions. Generally, where the scientific data and modeling analyses provide reasonable certainty that the pollutant's emissions are a significant contributor to ambient PM2. 5 concentrations, we believe that pollutant should be identified as a "regulated NSR pollutant" and subject
to the PM2. 5 NSR provisions. C6nversely, where the effect ofa pollutant'g emissions on ambient PM2. 5 concentrations is subject to substantial uncertainty, such that in some circumstances the pollutant may not result in formation ofPM2.5,or control ofthe pollutant may have no effect or may even aggravate air quality,.we generally believe it is unreasonable to establish a nationally-applicable presumption that the pollutant is a regulated NSR pollutant subject to the requirements ofNSR for PM 2.5. We discuss our final action with respect to ,each ofthe PM2.5 precursors and the basis for that action in sections V.A.2 through 5.

For those precursors that are either presumed to be regulated or not regulated (NOx, VOC, and ammonia), a State program need not follow the presumed approach if it can be demonstrated that the precursor in question is not, or is, a "significant contributor" to PM2. 5 concentrations within the specific area. "Significant contribution" in this context is a different concept than that in section 110(a)(2)(D) ofthe Act. Section 110(a)(2)(D) ofthe Act prohibits States from emitting air pollutants in amounts which significantly contribute to nonattainment or other air quality problems in other States. Consistent with the previous discussion ofsections 189(e) and 302(g), we are clarifying that the use in this NSR implementation rule ofthe term "significant contribution" to the area's PM2. 5 concentration means fhat a significant change in emissions of the precursor from sources in the area would be projected to provide a significant change in PM2.5 concentrations in the area. For example, ifmodeling indicates that a reduction in

an area's NOx emissions would reduce ambient PM2.5 levels in the area, but that

a reduction in ammonia emissions would result in virtually no change in ambient PM2.5 levels, this would suggest that NOx is a significant contributor but that ammonia is not. We are not 

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establishing in this rule a quantitative test for determining whether PM2 .5 levels in an aiea change significantly in response to reductions in precursor emissions in the area. However, in considering this question, it is relevant to consider that relatively small reductions in PM2. 5 levels are estimated to result in worthwhile public health benefits.

This approach to identifying a precursor as a regulated NSR pollutant reflects atmospheric chemistry conditions in the area and the magnitude ofemissions ofthe precursor in the area. Assessments ofwhether it is technically feasible and cost effective to control particular emissions units at

a source should be part ofthe later BACT determination within a permit action, and should occur after the basic assessment ofwhich precursors are to be regulated NSR pollutants in an area is completed. I Most commenters did not question

our legal authority to identify and regulate PM2. 5 precursors. However,

some commenters argued, based on the language ofsections 302(g) and 189(e) of the Act, that once we have designated

a compound as a precursor, we do not have discretion to presumptively exclude it from NSR requirements. Other commenters on this issue indicated that we do have such discretion, based on the deminimis doctrine ofthe AlabamaPowerdecision

or on practical implementation considerations such as the uncertainty in measuring and modeling the effect of PM 2. 5 precursors. We do not agree with the comment that the Act does not give us discretion to presumptively exclude a PM 2. 5 precursor from NSR requirements. As stated previously, we believe that section 302(g) allows the Administrator to presumptively notrequire certain precursors to be addressed in PM2.5 NSR programs generally, while allowing the State or EPA to make a finding for a specific area to override the general presumption. In the following pollutantspecific sections ofthis preamble, we find that at this time there is sufficient uncertainty regarding whether certain precursors significantly contribute to PM 2. 5 concentrations in all areas such that the policy set forth in this rule does not presumptively require certain precursors (ammonia, VOC) to be controlled in each area. However, the State or EPA may reverse the presumption and regulate a precursor if it provides a demonstration showing that the precursor is a significant contributor to PM2. 5 concentrations in the area. In addition, ifin the State's NSR program adoption process a commenter provides additional information suggesting an alternative policy for regulating a particular precursor, the Stdte will need to respond to this information in its rulemaking action.

Hence, we continue to believe that the Act provides us the authority not only to identify and regulate precursors to PM2.5,but also to treat precursors ofthe

same pollutant differently under the

same program.
3: Final Action on SO2

Sulfur dioxide is emitted mostly from the combustion offossil fuels inboilers operated by electric utilities and other industrial sources. Less than 20 percent of SO 2 emissions nationwide are from other sources, mainly other industrial processes such as oil refining and pulp and paper production. The formation of sulfuric acid from the oxidation ofSO 2 is an important process affecting most

areas in North America. There are three different pathways forthis transformation.

First, gaseous SO 2 can be oxidized by the hydroxyl radical (OH) to create sulfuric acid. This gaseous SO2 oxidation reaction occurs slowly and only in the daytime. Second, SO2 can, dissolve in cloud water (orfog or rainwater), and there it can be oxidized to sulfuric acid by a variety ofoxidants,

or through catalysis by transition metals such as manganese or iron. If ammonia is present and taken up by the water droplet, then ammonium sulfate will form as a precipitate inthe water droplet. After the cloud changes and the droplet evaporates, the sulfuric acid or ammonium sulfate remains in the atmosphere as a particle. This aqueous phase production process involving oxidants can be very fast; in some cases all the available SO 2 can be oxidized in less than an hour. Third, SO 2 can be oxidized inreactions in the particlebound water in the aerosol particles themselves. This process takes place continuously, but only produces appreciable, sulfate in alkaline (dust,sea salt) coarse particles. Oxidation ofSO 2 has also been observed on the surfaces ofblack carbon and metal oxide particles. During the last 20 years, much progress has been made in understanding the first two major pathways, but some important questions still remain about the smaller third pathway. Models indicate that more than halfofthe sulfuric acid in the eastern United States and in the overall atmosphere is produced in clouds.

The sulfuric acid formed from these pathways reacts readily with ammonia

to form ammonium sulfate, (NI) 2SO 4. If there is not enough ammonia present .to fully neutralize the produced sulfuric acid (one molecule ofsulfuric acid requires two molecules ofammonia), part of it exists as ammonium bisulfate; NH4HSO4 (one molecule ofsulfuric acid and one molecule ofammonia) and the particles are more acidic than ammonium sulfate. In certain situations (inthe absence of sufficient ammonia for neutralizatibn), sulfate can exist in particles as sulfuric acid, H 2 80 4. Sulfuric acid often exists in the plumes ofstacks where SO 2,sulfur trioxide (SOs), and water vapor are in much higher concentrations than in the ambient atmosphere, but these concentrations become quite small as the plume is cooled and diluted by mixing. Because sulfate is a significant component (e.g., ranging from 9 percent to 40 percent) of PM2. 5concentrations, and contributes to other air quality problems in all regions ofthe country,

we proposed to require States to treat SO2 as a PM2. 5 precursor in all areas. We

are retaining the same approach for SO2 in this final rule. Sulfate is an important precursor to PM2 . 5 formation in all areas, and has a strong regional impact on PM2. 5 concentrations. This apprbach is consistent with past EPA regulations, such as the Clean Air Interstate Rule (CAIR), the Clean Air Visibility Rule, the Acid Rain rules, and the Regional Haze rule, each ofwhich require SO 2 reductions to address fine particle pollution and related air quality problems. Finally, we do not believe that regulating SO 2 as a precursor to PM2. 5 is likely to add a majorburden to sources, as S02 is already regulated as part ofthe NSR program for the SO 2 NAAQS.

Most commenters who addressed this issue agreed that SO 2 should be regulated as a PM2. 5 prQcursor, although

one only supported regulation of SO2 as
a precursor in NA NSR, and not under PSD. Two commenters disagreed that SO 2 acts as precursors to PM2. 5 in all

cases and indicated that it should not be regulated as an "always-in" precursor.

We find the commenters' arguments against regulating SO 2 as a precursor unpersuasive. Sulfate is a significant fraction ofPM2 5 mass in all nonattainment areas currently, and although large SO 2 reductions are projected from electric generating units with the implementation ofthe CAIR program, sulfate is still projected to be

a key contributor to PM2 . 5 concentrations in the future, in both attainment and'nonattainment areas. Sulfur dioxide emissions also lead to sulfate formation on both regional and local scales. 

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4. Final Action on NOx

The sources ofNOx are numerous and widespread. The combustion offossil fuel generates the majority of NOx emissions, with large contributions from
power generation and mobile sources. Nitrates are formed from the oxidation of NOx into nitric acid (HN0 3) either during the daytime (reaction with OH)

or during the night (reactions with

ozone and water). Nitric acid continuously transfers between the gas and the condensed phases through condensation.and evaporation processes in the atmosphere. However, unless it
reacts with other species (such as ammonia, sea salt, or dust) to form a neutralized salt, it will volatilize and
not be measured using standard PM2. 5 measurement techniques. The formation ofaerosol ammonium nitrate is favored by the availability ofammonia, low temperatures, and high relative humidity. Because ammonium nitrate is semivolatile and not stable in higher temperatures, nitrate levels are typically lower in the summer months and higher in the winter months. The resulting ammonium nitrate is usually in the submicrometer particle size range. Reactions with sea salt and dust lead to the formation ofnitrates in coarse particles. Nitric acid may be dissolved. in ambient aerosol particles.

Based on a review of speciated monitoring data analyses, it is apparent that nitrate concentrations vary significantly across the country. For example, in some southeastern locations, annual average nitrate levels

are in the range of6 to 8 percent oftotal PM2.5 mass, whereas nitrate comprises 40 percent or more ofPM2.5 mass in certain California locations. Nitrate formation is favored by the availability of ammonia, low temperatures, and high relative,humidity. It is also dependent upon the relative degree ofnearby SO 2 emissions because ammonia reacts preferentially with SO 2 over NOx. Reductions in NOx emissions are expected to reduce PM2.5 concentrations in most areas. However, it has been sfiggested that in a limited'number of
areas, NOx control would result in increased PM 2.5 mass by disrupting the

ozone cycle and leading to increased oxidation of SO 2 to form sulfate .particles, which are heavier than nitrate particles.

Because ofthese factors, we are finalizing our proposed approach to NOx as a precursor to PM2.5 for the NSR program. Under this approach, NOx is presumed to be a significant contributor
to ambient PM2.5 concentrations in all PSD and NA NSR areas. However, a State or'EPA may rebut this presumption for a specific area ifthe State demonstrates to the Administrator's satisfaction orEPA demonstrates that NOx emissions in that

area are not a significant contributor to that area's ambient PM2. 5 concentrations. Ifa State or EPA makes such a demonstration, NOx would not be considered a PM2.5 precursor under the NSR program in that area. If a State

or EPA does not make such a demonstration, NOx must be regulated

as a precursor under the PSD, NA NSR, and minor source programs for PM 2.5. As discussed previously, this "presumed-in" approach is warranted based on the well-known transformation ofNOx into nitrates, coupled with the fact that nitrate concentrations vary significantly around the country. This approach is consistent with other recent EPA regulations requiring NOx reductions, which will reduce fine particle pollution, such as the CAIR and

a numbei ofrules targeting onroad and nonroad engine emissions.

We had proposed that NOx be presumed to be aprecursor in any State thatEPA has identified as a source of the PM 2 . 5 interstate transport problem. In the final rule, we have dropped this requirement to be consistent with EPA's Clean Air Fine Particle Implementation Rule published on April 25, 2007. 72 FR 20586. Such a requirement is not necessary in this rule because States that contribute to downwind nonattainment forPM2. 5 are otherwise required to address transported NOx emissions under the CAIR.

In areas where NOx is regulated as a precursor to PM2. 5, we do notbelieve that this is likely to add a major burden to sources, as NOx is already a regulated NSR pollutant. This is because NOx is

an identified precursor for the ozone NAAQS and an indicator for the NO2 NAAQS. Several commenters agreed that NOx should be regulated under major NSR as
a precursor to PM2.5. Some of these commenters believe that States should not have the opportunity to demonstrate otherwise, orindicated that a waiver for exclusion of NOx as a precursor should be allowed only ifdownwind States approve such awaiver. A few commenters stated that NOx should not be regulated as a precursor to PM 2.5in the major NSR program, either on grounds of scientific uncertainty regarding the impact ofNOx emissions

on ambient PM2. 5 concentrations or on policy grounds (i.e.,because NOx is already regulated under NSR for other NAAQS).

We are not persuaded by the argument that NOx should notbe regulated as a PM 2.5precursor because it is a regulated pollutant under other NAAQS. We do not find the degree of scientific uncertainty regarding PM 2. 5 formation from NOx to be great enough to preclude regulation ofNOx as a precursor with an opportunity for a case-by-case demonstration that NOx is not a significant contributor. Furthermore, the fact that we regulate NOx for other NAAQS under the NSR program does not by itselfjustify declining to regulate NOx as a PM2.5 precursor in circumstances where NOx also significantly contributes to PM2. 5 formation. As noted earlier, the regulation ofNOx as a precursor for PM 2.5 is not expected to add a major burden to regulated sources that are already required to limit NOx emission to meet other NAAQS.

We disagree with the commenters who believe that emissions of NOx cannot be correlated to PM2.5 formation,

or that it is unclear when NOx acts as
a precursor. As discussed previously,

our decision to regulate NOx as a precursor to PM2.5is based onthe wellknown transformation ofNOx into nitrates. Nevertheless, nitrate concentrations vary significantly across the country. As a result, we believe that the "presumed-in" approach is appropriate-for NOx since a State can demonstrate that NOx should not be a precursor in a given area or region.

While we recognize that NOx emissions can affect PM2. 5 - concentrations in downwind areas, we disagree that approval from downwind States should be required'for a State to exclude NOx as a PM2. 5 precursor for a particular area. This is because States that contribute to downwind nonattainment for PM2. 5 are otherwise required to address transported NOx emissions under the CAIR.
5. Final Action on VOC

The organic component ofambient particles is a complex mixture of hundreds or even thousands oforganic compounds. These organic compounds

are either emitted directly from sources (i.e.,primary organic aerosol) or can be formed by reactions in the ambient air (i.e., secondary organic aerosol, or SOA). Volatile organic compounds are key precursors in the formation processes for both SOA and ozone. The relative importance of organic compounds in the formation of secondary organic particles varies from

area to area, depending upon local emissions sources, atmospheric chemistry, and season ofthe year. -

The lightest organic molecules (i.e., molecules with six or fewer carbon atoms) occur in the atmosphere mainly

as vapors and typically do not directly 

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form organic particles at ambient temperatures due to the high vapor pressure oftheir products. However, they participate in atmospheric chemistry processes resulting in the formation ofozone and certain free radical compounds (such as OH) which in turn participate in oxidation reactions to form SOA, sulfates, and nitrates. These VOCs include all alkanes with up to six carbon atoms (from methane to hexane isomers), all alkenes with up to six carbon atoms (from ethene to hexene isomers), benzene, and many low-molecular weight carbonyls, chlorinated compounds, and oxygenated solvents.

Intermediate weight organic molecules (i.e.,-compounds with 7 to 24 carbon atoms) often exhibit a range of volatilities and can exist in both the gas and aerosol phase at ambient conditions. For thisreason they are also referred to as semivolatile compounds. Semivolatile compounds react in the atmosphere to form SOA. These chemical reactions are accelerated in

warmer temperatures, and studies show that SOA typically comprises a higher percentage of carbonaceous PM in the

summer as opposed to the winter. The production ofSOA from the atmospheric oxidation of a specific VOC depends on four factors: Its atmospheric abundance, its chemical reactivity, the availability of oxidants (ozone, OH, HNO3), and the volatility ofits products. In addition, recent work suggests that the presence ofacidic aerosols may lead to an increased rate ofSOA formation. Aromatic compounds such as toluene, xylene, and trimethyl benzene are considered to be the most significant anthropogenic SOA precursors and have been estimated to be responsible for 50 to 70 percent oftotal SOA in some airsheds. Man-made sources of aromatics gases include mobile sources, petrochemical manufacturing, and solvents. Some ofthe biogenic hydrocarbons emitted by trees are also considered to be important precursors of secondary organic PM. Terpenes (andbpinene, limonene, carene, etc.) and the sesquiterpenes are expected to be fiajor contributors to SOA in areas with significant vegetation cover, but isoprene is not. Terpenes are very prevalent in areas with pine forests, especially in the southeastern United States. The rest ofthe anthropogenic hydrocarbons (higher alkanes, paraffins, etc.) have been estimated to contribute 5 to 20 percent to the SOA concentration depending on the area.

The contribution ofthe primary and secondary components oforganic aerosol to the measured organic aerosol concentrations remains a complex issue. Most ofthe research performed to date has been done in southern California, and more recently in central California, while fewer studies have been completed on other parts ofNorth America. Many studies suggest that the primary and secondary contributions to total organic aerosol concentrations are highly variable, even on short time scales. Studies ofpollution episodes indicate that the contribution of SOA to the organic PM can vary from 20 percent to 80 percent during the same day.

Despite significant advances in understanding the origins and properties ofSOA, it remains probably the least understoQd component of PM2. 5. The reactions forming secondary organics are complex, and the number of intermediate and final compounds formed is voluminous. Some ofthe best efforts to unravel the chemical composition of ambient organic aerosol matter have resulted in quantifying the concentrations ofhundreds oforganic compounds representing only 10 to 20 percent ofthe total organic aerosol

mass. For this reason, SOA continues to be a significant topic ofresearch and investigation.

Current scientific and technical information shows that carbonaceous material is a significant fraction oftotal PM2. 5 mass in most areas, that certain VOC emissions are precursors to the formation of SOA, and that a considerable fraction ofthe total carbonaceous material originates from local as opposed to regional sources. However, while significant progress has been made in understanding the role of gaseous organic material in the formation of organic PM, this relationship remains complex. We recognize that further research and technical tools are needed to better characterize emissions inventories for specific VOC, and to determine the extent of the contribution ofspecific VOC to organic PM mass.

As a result, this final rule does not, in general, require regulation ofVOC as a precursor to PM2.5 forthe NSR program. However, a State may demonstrate to the Administrator's satisfaction or EPA may demonstrate that VOC emissions in

a specific area are a significant contributor to that area's ambient PM 2 . 5 concentrations. After such a demonstration, the State would regulate VOC (ora subset ofVOC) as a PM 2 . 5 precursor for the NSR program in that

area. That is, the State would need to regulate construction and modification of stationary sources that increase emissions ofVOC in that area to assure that these emissions do not interfere with reasonable further progress orthe ability ofthat area to attain Or maintain the PMi. 5NAAQS.
We believe that this "presumed-out" approach is appropriate for VOC because of the complexity in assessing the role ofVOC in PM2.5 formation, as discussed previously. Where the effect ofa pollutant's emissions on ambient PM 2.5concentrations is subject to this degree ofuncertainty, we do not have justification to establish a nationallyapplicable presumption that the pollutant is a regulated NSR pollutant subject to the requirements ofNSR for PM 2 .5. Under the circumstances, we believe the best policy is to continue to regulate VOC under NSR as aprecursor to ozone in all areas, which will potentially provide a co-benefit for PM2.5 concentrations despite the uncertainty in PM2.5formation from VOC. As discussed previously, we do not find it appropriate to utilize the

same approach for NOx because the scientific data and modeling analyses provide more certainty that NOx emissions are a significant contributor to ambient PM2.5concentrations.

Note that we intend to regulate high molecular weight VOC (with 25 carbon
atoms ormore and low vapor pressure)

as direct PM2.5 emissions because they

are emitted directly as primary organic particles and exist primarily in the condensed phase at ambient temperatures. See section V.E following for more on the regulation ofsuch "condensables."

Most commenters agreed with the "presumed-out" approach for VOC. One commenter gaid that the role of VOC in the formation ofPM2.5 is sufficiently understood to recommend a "waiver" approach forthis pollutant in the same way as NOx is treated for PM 2. 5 in the rule.

As discussed previously, the reactions forming secondary organics are complex and the number ofintermediate and final compounds formed is voluminous. Some ofthe best efforts to unravel the chemical composition ofambient organic aerosol matter have merely been able to quantify the concentrations of hundreds oforganic compounds representing only 10 to 20 percent ofthe total organic aerosol mass. For this
reason, SOA continues to be a significant topic ofresearch and investigation. Accordingly, we do not agree with the commenter who suggested a waiver or "presumed-in" approach for VOC. We continue to believe that our "presumed-out" approach is most appropriate for VOC and have included this approach in the final iules. 

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6. Final Action on Ammonia

Ammonia (NH 3) is a gaseous pollutant that is emitted by natural and anthropogenic sources. Emissions inventories for ammonia are considered
to be among the most uncertain of any species related to PM. Ammonia serves
an important role in neutralizing acids in clouds, precipitation, and particles. In particular, ammonia neutralizes sulfuric acid and nitric acid, the two key contributors to acid deposition-(acid rain). Deposited ammonia also can contribute to problems of eutrophication in water bodies, and deposition of ammonium particles may effectively result in acidification of soil as ammonia is taken up by plants. The NARSTO Fine Particle Assessment 8 indicates that reducing ammonia emissions where sulfate concentrations

are high mayreduce PM 2.5 mass concentrations, but may also increase the acidity ofparticles and precipitation. An increase in particle acidity is suspected to be linked with adverse human health effects and with

an increase in the formation of secondary organic compounds. Based

on this information and further insights gained from the NARSTO Fine Particle Assessment, it is apparent that the formation of particles related to ammonia emissions is a complex, nonlinear process.

Though recent studies have improved

our understanding ofthe role of ammonia in aerosol formation, ongoing research is required to better describe the relationships between ammonia emissions, PM concentrations, and related impacts. The control'techniques for amnionia and the analytical tools to quantify the impacts ofreducing ammonia emissions on atmospheric aerosol formation are both evolving. Also, area-specific data are needed to evaluate the effectiveness ofreducing ammonia emissions on reducing PM2. 5 concentrations in different areas, and to determine where ammonia decreases may increase the acidity ofparticles and precipitation.

Due to the considerable uncertainty related to ammonia as a precursor, our final rules do not require ammonia to be regulated as a PM2.5 precursor but do give States the option to regulate ammonia as a precursor to PM2. 5 in nonattainment areas for purposes of NSR on a case-by-case basis. Consistent with our proposal, ifa State

8NARSTO (2004) "Particulate Matter Assessment for Policy Makers: A NARSTO Assessment." P. McMurry, M. Shepherd, and J. Vickery, ads. Cambridge University Press, Cambridge, England. ISBN 0 52 184287 5. See the docket for this -rulemaking, Docket ID No. EPA-HQ-OAR-2003- 0062, or http://www.narsto.org/section.src?SID-6. demonstrates to the Administrator's satisfaction that ammonia emissions in

a specific nonattainment area are a significant contributor to that area's ambient PM2.5concentrations, the State would regulate ammonia as aPM2.5 precursor under the NSR program in that nonattainment area. Once this demonstration is made, ammonia would be a "regulated NSR pollutant" under NA NSR for that particular nonattainment area, and the State would need to regulate construction and modification of stationary sources that increase emissions of ammonia in that

area to assure that these-emissions do not interfere with reasonable further progress or the ability ofthat area to attain or maintain the PM2.5 NAAQS. In all other npnattainment areas in that State and nationally, ammonia would
not be subject to the NSR program. In addition, the action ofany State identifying ammonia emissions as a significant contributor to a nonattainment area's PM 2.s concentrations, or our approval of a nonattainment SIP doing so, does not make ammonia aregulated NSR pollutant for the purposes ofPSD in any attainment or unclassifiable areas nationally. This is consistent with our proposal (70 FR 66036) and no commenters took issue with the proposal. We also retain the ability to make a technical demonstration for any

area in a State, ifappropriate, to reverse the presumption and require ammonia
to .beaddressed in that State's nonattainment area plan.

We elected to finalize the proposed approach because ofcontinued uncertainties regarding ammonia emission inventories and the effects of ammonia emission reductions. Ammonia emission inventories are presently very uncertain in most areas, complicating the task of assessing potential impacts ofammonia emissions reductions. In addition, data necessary to understand the atmospheric composition and balance ofammonia and nitric acid in an area are not widely available, making it difficult to predict the results ofpotential ammonia emission reductions. Ammonia reductions maybe effective and appropriate for reducing PM2. 5 concentrations in selected locations, but in other locations such reductions may lead to minimal reductions in PM2,5 concentrations and increased atmospheric acidity. Research projects continue to expand our collective understanding ofthese issues, but at this time we believe this case-by-case approach for fionattainment areas is appropriate given that there is sufficient uncertainty regarding the impact of ammonia emission reductions on PM2.5 concentrations in all nonattainment

areas. In light ofthese uncertainties, we encourage States to continue efforts to better understand the role of ammonia in their fine particle problem areas.

Several commenters agreed with our "presumed-out" approach for anunonia. One ofthese commenters recommended that we recognize the role ammonia plays in PM2.5formation and develop a policy to require the minimization and mitigation ofknown emissions of ammonia, while another suggested that

we require States to initiate comprehensive ambient'air monitoring networks to determine the extent of local effects of ammonia.

Four commenters did not support treating ammonia as a PM 2.5 precursor under any circumstances. Three of-these
commenters stated that if EPA permits States to demonstrate that ammonia shouldbe regulated as aPM 2.5 precursor for NSR purposes, we should make clear that ammonia emissions from the operation ofan air pollution control system to control NOx should not factor into such a demonstration.

Two commenters preferred that we
use the "presumed-in" approach for ammonia, as for NOx. One ofthese commenters stated that the "presumedout" approach would improperly delegate our authority to regulate ammonia as a PM2.5precursor to the States and would reverse Congress' requirement to regulate PM precursors unless the emissions are not part ofthe problem, instead taking the approach that we will "not regulate unless proven to be part ofthe problem."

We continue to believe that the "presumed-out" approach is most appropriate for ammonia. As discussed previously, considerable uncertainties remain regarding ammonia emission inventories and the effects ofammonia emission reductions. As a result, we do not believe it advisable to adopt a "presumed-in"_ approach. However, where a State can gather sufficient data to demonstrate that reductions in ammonia emissions will decrease ambient concentrations ofPM2. 5 in a particular nonattainment area, we believe that the State should be allowed
to regulate ammonia emissions under its PM 2.5NSR program for that area.

, We do notbelieve that this approach improperly delegates authority to the States. The final rule establishes a general presumption for all nonattainment areas through this rulemaking process, and allows for the presumption to be modified by the State

on a case-by-case basis with EPA approval. Under the Clean Air Fine 

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Particle Implementation Rule (72 FR 20586, April 5, 2007).(addressing various nonattainment plan elements other than NSR), we still retain the ability to make a technical demonstration for any area if appropriate to reverse the presumption and require ammonia to be addressed in its nonattainment area plan. As discussed previously in section V.A.1,

we interpret the Act to allow the "presumed-out" approach adopted in the final rule.

We agree with the commenter who suggested that we continue research on the role ofammonia in the formation of PM 2.5. We believe that it is prudent to. continue research on ammonia control technologies and'the ammonia-sulfatenitrate-SOA equilibrium before undertaking abroad national program to reduce ammonia emissions. As we develop a greater understanding about the potential air quality effects of

. reducing ammonia emissions in specific nonattainment areas, it may be appropriate for ammonia reduction strategies to be included in future SIPs. At this time, however, we believe that reducing S02 and NOx emissions will achieve significant reductions in ambient PM2 5 concentrations.

Regarding the comment related to ammonia emissions from NOx control systems, we believe that a State should evaluate all sources ofammonia emissions when determining whether to regulate ammonia under its PM2.5NSR program for a particular nonattainment

area. However, we also encourage States
to be mindful ofthe potential tradeoff in terms ofambient PM2.5 concentrations that may be related to reducing ammonia emissions from NOx control systems.
B.MajorStationarySource Threshold forPM2. 5 The majorNSR program applies to construction ofmajor stationary sources and major modifications at major stationary sources. A stationary source is a "major source" ifits actual emissions or its potential to emit for a. specific pollutant equals orexceeds the major source threshold for that pollutant established in the Act. Different pollutants, including precursors, are not summed to determine applicability.



### , Sections 169 and 302(j) ofthe Act contain definitions of"major emitting facility" and "major stationary source" that apply to programs implemented under part C and subpart 1 ofpart D of the Act (PSD and NA NSR, respectively). Consistent with our proposal, these final rules follow these definitions forpurposes ofdefining a major emitting facility or.major ; stationary source that wouldbe subject to major NSR. The thresholds set out in the definitions are applied to each relevant pollutant individually, that is,

to direct PM2.5 emissions and to emissions ofeach pollutant identified as

a PM2. 5 precursor for the applicable NSR
program. Under the final rules, the inajor source thresholds are as follows:

PSD

............. 100 tpy for source categories

listed in 40 CFR 51.166(b)(1)(i)(a) and 52.21 (b)(1)(i)(a). 250 tpy for all other source

categories. NA NSR

...... 100 tpy for all source categories.

No regulatory change is required to implement this approach to the major

source thresholds for direct PM2. 5 emissions and the PM 2.5 precursors. See
"40 CFR 51.165(a)(1)(iv)(a),

51.166(b)(1)(i), 52.21(b)(1)(i), and part 51, appendix S,section II.A.4.

This approach is consistent with'how

we treat other criteria pollutants that are covered by subpart 1 ofpart D ofthe Act. Nonattainment NSR programs under subpart 1 do not include a tiered classification system such as the one required for ozone nonattainment areas under subpart 2 ofpart D. We do not interpret subpart 4 of part D ofthe Act (creating "serious" and "moderate" classifications for PM10 nonattainment areas) as applying to PM 2.5.

•Although our approach is consistent with sections 169 and 302(j) and subpart 1 ofpart D ofthe Act, it results in a higher major source threshold in PM2.5 nonattainment areas than the major

source threshold that applies in some PM 10 nonattainment areas under subpart 4 ofpart D ofthe Act. This is because section 189(b) ofthe Act establishes a 70-tpy major source threshold for "serious" PM 1 0 nonattainment areas while "moderate" PM 0 nonattainment

areas apply a 100-tpy major source threshold based 6nthe definition in section 302(j). We do not believe the Act gives us the discretion to promulgate a lower major source threshold for pollutants such as PM2.5 that are only subject to subpart 1 ofpart D ofthe Act.

Our emissions inventory data do not indicate that this situation will adversely impact attainment ofthe PM2. 5 NAAQS. These data indicate that

a significant number of sources have actual PM2. 5 emissions in the 100 to 250 tpy range. Additionally, our more current inventory data show that the number ofsources that would be covered as major sources by a lower major source threshold would not increase substantially unless thd threshold were lowered to 20 tpy or below. Thus, even ifEPA had the discretion to adopt a 70-tpy major

source threshold forPM2. 5 nonattainment areas, our data indicate that few additional sources would be subject to the major NSR program in PM2.5 nonattainment areas. 9

We believe that States should consider such information in developing their own SP-approved NSR programs. For example, ifconstruction ofPM2.5 sources emitting 99 tpy with no major NSR controls and without mitigation would undermine a State's ability to achieve reasonable further progress or attain the PM2. 5 NAAQS, the State should consider imposing emissions controls or other requirements on these sources through the State's minor NSR program. Note that such programs are required under the existing statute and regulations to

assure that the NAAQS are achieved. See section 110(a)(2)(C) ofthe Act and 40 CFR 51.160. In addition, States may address such sources through other elements in their nonattainment area SIPs that are not statutorily bound to the definition ofmajor source, as the major NSR program is. We reiterate that since

we do not interpret subpart 4 ofthe Act
to apply to PM2.5,we do not believe that

we have discretion under section 302(j) ofthe Act to define a lower major source threshold for pollutants such as PM2.5 that are only subject to subpart 1 ofpart .D of the Act. Some commenters indicated that State minor NSR programs would notbe sufficient to address such sources due to interstate transport and the existence of interstate PM2. 5 nonattainment areas. These commenters indicated -thata lower major source threshold for PM2.5 sources located in designated nonattainment areas should be applied uniformly throughout the entire nonattainment area, which would notbe. possible when minor NSR programs are defined on a State-by-State basis.

We believe, to the contrary, that States

can coordinate their minor NSR programs to address interstate PM2. 5 nonattainment areas, and we encourage them to do so. In addition, we note that the impacts ofdirect PM 2. 5 emissions

are generally felt primarily in the local

area.

One commenter stated that in order to address the impact ofhigh PM concentrations, the Act mandates EPA to define a criteria pollutant's NSR major threshold at levels less than 100 tpy. The commenter gave the example of

9 See "NEI-PM2

_ 5 Source Analysis" in the docket for this rulemaking, Docket ID No. EPA-HQ-OAR2003-0062. 

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subparts 2 and 4 ofpart D ofthe Act, which define lower major source thresholds for certain classifications of

ozone and PMo nonattainment areas, respectively. The commenter argued that it is unreasonable for us to assert that subpart 4 does not apply to this rlle because it regulates all PM with a diameter ofless than 10 micrometers, which includes PM2. 5. The commenter believes that we recognized as much in

our proposal preamble discussion ofthe options for implementing reasonably available control technology (RACT), where we discussed potential " approaches that "would be consistent with the approach set forth in theAct in subpart 4." 70 FR 66017..This commenter stated that a reasonable interpretation ofthe Act requires major

sources-of direct PM2 . 5 emissions and precursor emissions to be defined at a baseline level of70 tpy, and adjusted further downward as appropriate considering the characteristics and potential impacts ofthe pollutants.

We do not agree that subpart 4 ofpart D applies t0PM2. 5 nonattainment areas. Subpart 4 was added to the Actby Congress specifically to address the PM 1oNAAQS. We believe that the PM2. 5 standard should be implemented under subpart 1 ofpart D, which is the general provision of the Act related to NAAQS implementation. Part D oftitle Iof the Act sets forth the requirements for SIPs needed to attain the NAAQS. Part D also includes a general provision under subpart 1, which applies to all NAAQS for which a specific subpart does not exist. Because the PM2.5 standards were not established until 1997, the nonattainment plan provisions found in section 172 of subpart 1 apply. Subpart 4 on its face applies only to the PM 10 standard. Ingeneral, the emphasis in subpart 4 onreducing PM1o concentrations -fromcertain sources of direct PM2.5emissions can be somewhat effective in certain PM 2.5 nonattainment

areas but not in all. Contributions to PM2.5concentrations are typically from

a complex mix of sources of primary emissions and sources of precursor emissions, which form particles through reactions in the atmosphere. In addition, PM 2.5differs from PM 1 oin terms of atmospheric dispersion characteristics, chemical composition, and contribution from regional transport.

A group ofenvironmental
commenters believed that EPA should be consistent with the stationary source size thresholds proposed for RACT in option 2, see 70 FR 66019/1. In our proposal preamble discussion ofRACT, while we discussed developing a classification system for PM 2.5 nonattainment areas under section 172(a)(1) of subpart 1, we did not discuss subjecting PM2. 5 to the requirements of subpart 4. While our discussion ofRACT contemplated a lower threshold for RACT applicability in'some PM2. 5 nonattainment areas, we did not characterize this as defining a lower major source threshold. Moreover, section 302(j) defines a major stationary

source as one that emits 100 tpy or more "except as otherwise expressly provided." Since section 172 does not expressly provide EPA with the authority to promulgate a major source threshold below 100 tpy, we do not believe we are authorized to do so under subpart 1 ofpart D ofthe Act.

One commenter stated that the major

source threshold for PM2.5 emissions should be calculated using the current SO 2 and NOx definitions ofmajor

source and significant emissions rate.. Specifically, the commenter suggested that the ratio ofthese values (100 tpy and 40 tpy, respectively) should be multipfied by the significant emissions
rate for direct PM 2.5emissions (10 tpy;

see section V.C following) to yield a PM 2 .5 major source threshold of25 tpy. As previously stated, we do not believe that we have discretion under the Act to define a lower major source threshold under subpart 1 ofpart D of the Act. In any case, the major source thresholds and significant emissions rates for SO 2 and NOx were not defined in relation to one another, and therefore their relationship would not provide a suitable basis for developing the PM?. 5 major source threshold from the PM2. 5 significant emissions rate. Major source thresholds are defined directly in the Act, while the significant emissions
rates were codified independently in regulations through a modeling analysis of ambient impacts.

C.SignificantEmissionsRate forDirect Emissionsof PM2. 5 The determination of what should be classified as a modification subject to major NSR is based, inpart, on a "significant emissions rate." 10 The major NSR regulations define this term

as a rate above which anet emissions increase will trigger major NSR permitting requirements, ifthe increase results from amajor modification. Sources are exempt from major NSR requirements ifthe emissions increase resulting from a modification is below this ratebecause EPA considers such lower emissions increases to be de minimisfor purposes ofthe major NSR program.

The significant emissions rates for the criteria pollutants other than PM 2.5 are given inthe following table:

Criteria pollutant Significant emissions rate (tpy)

Ozone

................................................................. VOC: Any increase up to 40 tpy (dependent on NA classification). NOx: Any increase up to 40 tpy (dependent on NA classification). NO2

.....................................

..... ..... .... ..... ..... ..... ... NOx: 40 tpy. Particulate Matter

............................................. 25 tpy, particulate matter emissions. 15 tpy, PM 1o emissions. CO

................................. 50 or 100 tpy (dependent on NA classification). S02

..................................................................... 40

### tpy. Lead

.................................................................... 0.6 tpy.

Significant emissions rates for additional (non-criteria) pollutants that

are subject to the PSD program are contained in 40 CFR 51.166(b)(23).and 40 CFR 52.21(b)(23).

For direct ,emissionsof PM2.5, these final rules define the significant

t0 Foradditional background on EPA's interpretation ofmodification and rationale for emissions rate as 10 tpy. This is the level that we proposed as our preferred option. This final significant emissions
rate for direct PM2.5 emissions is based fundamentally on the same approach that we used in setting the previous

including significant emissions rates in defining significant emissions rates for PM emissions and PM 0 emissions.

Historically, the original significant emissions rate for PM (25 tpy of PM emissions) was set using a modeling analysis to determine the amount ofPM emissions that a source could emit that

major modifications, see 61 FR 38253-54 (Dec. 31,- 2002). 

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would be unlikely to cause ambient impacts above 4 percent ofthe PM NAAQS (measured as total suspended particulate (TSP)). 1 1 Although a range of

source configurations can yield awide range of impacts per tpy ofemissions,

our review oftypical configurations of major PM sources led us to the conclusion that a major modification that increased PM emissions by 25 tpy

or less would be unlikely to increase 24- hour average concentrations ofTSP by

more than 4 percent ofthe 24-hour TSP NAAQS. Subsequently, when we set the significant emissions rate for PM10, we adjusted the rate for PM emissions using the ratio ofthe 24-hour PM1oNAAQS to the 24-hour TSP NAAQS to derive the PM 10 significant emissions rate of 15 tpy. W6 used the ratio of 24-hour NAAQS for this adjustment because that NAAQS was controlling for both PM and PM10.

We used aconceptually similar methodology to derive the final PM2.5 significant emissions rate from the rate for PM10 . However, because the 24-hour NAAQS is not controlling for PM2.5,we revised the methodology to take into account the annual impact ofemissions. See the proposal preamble for additional information on the methodology we used to develop the final significant emissions rate for direct PM2.5 emissions (70 FR 66038).

Several commenters supported our approach to setting the significant emissions rate for direct PM2. 5 emissions and the level (10 tpy) based on the same methodology used for PM emissions and PM10 emissions. Numerous other commenters believe that our rethodology was too conservative, and suggested a significant emissions rate of 15 tpy. Two commenters suggested that

we use significant emissions rate of5 tpy or less. Another commenter suggested that we could "split the

"The EPA established the original NAAQS for PM id terms ofambient concentrations ofTSP (40. CPR 51.100(ss)). Source applicability for PM was .determined in terms ofamounts ofPM emissions (40 CFR 51.100(pp)) from the affected source. In 1993, at 58 FR 31622 (see page 31629), EPA eliminated TSP as the ambient indicator for measuring compliance with both the NAAQS and PSD increments. Thus, EPA no longer considers the TSP ambientindicator to be a regulated NSR pollutant. The EPA is currently evaluating whether itremains appropriate- to consider PM as a "regulated NSR pollutant." There is no NAAQS for TSP/PM, rather the standards address specific size fractions of PM, namely PM1e and PM 2. 5. However, PM emissions, based on in-stack measurements, continue to beregulated under PSD because ofthe

use ofsuch emissions for evaluating compliance under a variety ofCAA section 111 new source performance standards (40 CFRpart 60). Given the regulatory changes and positions taken by EPA since 1993, EPA is re-evaluating the implications forPM emissions in the NSPS program (and other airprograms) and will act accordingly to clarify this issue inthe near-term. difference," using an option that could give States and companies some flexibility: Modifications less than 5 tpy ofdirect PM2. 5 emissions could be considered de minimis;modifications between 5 and 15 tpy ofdirect PM2. 5 emissions could choose to either demonstrate less than a 4 percent NAAQS increase or simply be subject; and modifications with increases of 15

or more tpy ofdirect PM 2. 5 emissions would be subject.

We agree with commenters who indicated that we were correct in using the same methodology for direct PM 2 .5 that was used to setthe significant emissions rate forPM 1J and PM emissions. We do not agree that using the same-level as PM 1 oemissions (15 tpy) is warranted, given the demonstrated health effects of PM 2.5. Neither do we agree that a significant emissions rate of5 tpy or less is warranted. While our screening model

runs indicated that emissions increases in this range at facilities with short stacks can cause measurable increases in ambient PM2. 5 levels, we do not believe that facilities at the extremes. should dictate the program for all

sources.

We do not agree that inclusion of condensable emissions in future testing and applicability determinations (see section V.E) is grounds for increasing the SER for direct PM2. 5 emissions. The results of the modeling analysis that is the basis forthe SER of10 tpy is not affected by the nature ofthe direct PM2. 5 emissions (i.e., condensable or not).

We also do not agree that'the proportions ofprimary and secondary PM2.5 that comprise ambient PM2.5 concentrations is relevant to determining the appropriate SER for direct PM2.5 emissions. Following our historic approach for PM and PM10,we based our analysis on determining the size ofa source of direct PM2.5 emissions that would be expected to have an ambient impact of 4 percent or

more ofthe NAAQS. This relationship holds true regardless of the origin ofthe particles that make up the ambient PM2. 5. The commenter's approach (i.e., carrying outthe analysis based on onehalf ofthe NAAQS because primary PM2. 5 makes up only one-half ofthe ambient PM2.5)•implies that an increase in ambient PM2. 5 concentrations due to

an increase in direct PM2. 5 emissions is somehow automatically matched by a like increase in the ambient concentration ofsecondary PM2.5. We do not believe that this is a reasonable approach. D. Significant EmissionsRates forPM2. 5 Precursors

Consistent With the preferred option in the proposal, we are setting significant emissions rates for PM2. 5 precursors at the levels forthose pollutants already included in major NSR programs, as shown in the following table:
Significant emissions PM2.5 rate (equal to or precursor exceeding)

S0 2

........................... 40 tpy. NOx

.......................... 40 tpy. VOC

..................... 40 tpy. Ammonia

.................. Adopted inSIP.

VOC is presumed notto be a precursor to PM2. 5 in any attainment or unclassifiable area, unless the State demonstrates to the Administrator's -satisfactionor EPA demonstrates that emissions of VOC from sources in a specific .areaare a significant contributor to that area's ambient PM2. 5 concentrations. Any State making such

a demonstration would be required to adopt the 40-tpy significant emissions
rate unless it demonstrates that a more stringent significant emissions rate (lower rate) is more appropriate.

For ammonia, States determining in their SIPs that control ofammonia is a necessary part ofa PM2. 5 control strategy in a particular area must set the significant emissions rate for ammonia. Otherwise, according to the definition of "significant" in the PSD program, "any emissions rate" would be considered significant. See40 CFR 51.166(b)(23)(ii).

One commenter stated that we-should not leave it to States to set significant emissions rates for ammonia. The
commenter argued that EPA's scientists should shoulder this responsibility, and the resulting significant emissions rate should be subject to notice and
comment.

In the final rule, we are allowing those States that determine in their SIPs that control ofammonia is necessary to set the significant emissions rate for ammonia, based on the information developed for each attainment demonstration. At this time, we believe this is more appropriate than EPA setting a single, nationwide significant emissions ratebecause ofthe different role ammonia plays in the formation of PM2. 5 from one area to another, as well

as our still-evolving understanding of the impact ofreducing ammonia emissions on ambient PM2.5 concentrations. In dddition, we note that the SIP revisions that States undertake to add ammonia to their NA NSR

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programs are subject to notice and
comment rulemaking procedures.

Numerous commenters supported our proposal to set significant emissions
rates for PM2.5 precursors at the levels already used'for otherpurposes in the NSR program. One commenter indicated that since roughly half or more of ambient PM2.5 is derived from precursors, 140tpy would be an appropriate significant emissions rate for PM2. 5 precursor emissions. Another commenter suggested a significant emissions rate of4 ipy for SO 2 and 2 tpy forNOx, based on the percentage of PM2. 5 that is typically derived from these precursors and the ratios between the existing significant emissions rates for these pollutants and the SO 2 and NO 2 annual NAAQS. Since the ambient concentrations ofPM2.5vary across the country and since significant emissions rates have notbeen developed as a ratio of the NAAQS, we do not believe that the suggested approach is appropriate.

As discussed in the proposal, the use of existifig significant emission rates where the PM2,5 precursor is also regulated under NSR as a separate criteria pollutant harmonizes the NSR program for PM2. 5 with the NSR programs for those other criteria pollutants. This enables a source to determine the NSR impacts ofproposed modifications by reference to a single significant emissions rate for each pollutant, and enables streamlining of determinations regarding the applicable control technology and analysis ofair quality impacts into a single and comprehensive decision making process forboth PM2. 5 and other criteria pollutants that also cover PM2. 5 precursors. This also follows precedent. When ozone became a criteria pollutant, EPA used the NOx significant emissions rate from the NO2 program.

The burden imposed is not the only factor to consider when setting the significant emission rates for precursors-the process for determining the significant emission rates must also take into account the accuracy and certainty with which we can predict the effect ofthe precursors on PM 2. 5 concentrations. It is difficult to determine the ambient air quality effects that result from a single source of emissions ofPM2. 5 precursors. There are conservative screening models for predicting impacts oflarge NOx and SO2 sources on ambient PM2.5 concentrations. We conducted a range of modeling analyses to determine the
amount ofPM2.5 precursor emissions

- needed to show an increase in ambient PM2. 5 concentrations. These analyses showed that precursor emissions probably have some localized impacts, but that most impact is farther downwind as precursors have the time
to convert to PM2.5. In addition, the modeling available atthis time does not provide sufficient information to estimate impacts ofemissions from individual sources ofammonia and VOC on ambient PM 2 . 5 concentrations. While we know that precursors contribute to the formation ofPM 2 .

5 in the ambient air, the degree to which these individual precursors contribute to PM2.5 formation in a given location is complex and variable. There are competing chemical reactions taking place in the atmosphere, and meteorological conditions play a significant role in the size and characteristics ofparticle formation. For these reasons, we do not believe that we have adequate data on the impacts of precursor emissions from individual

sources to override the administrative advantages ofsetting the significant emissions rates for SO 2,NOx, and VOC for purposes ofthe PM2. 5 NSR program at the same levels that are already used for other purposes inthe major NSR program.

E.CondensablePM Emissions
In this final NSR rule, EPA will not require that States address condensable PM in establishing enforceable emissions limits for either PM 1 o or PM2. 5 inNSR permits until the completion of

a transition period, as described herein. In response to significant comments on the variability oftest methods available for measuring condensable emissions,

we have adopted this transition period approach to allow us to assess the capabilities ofthe test methods and possibly revise them to improve performance. The transition period will end January 1, 2011 unless EPA advances this date through the rulemaking process described below. Subsequent to the completion ofthe test methods assessment, EPA will be conducting a notice and comment rulemaking to codify new orrevised test methods. Once these new orrevised test methods are in place, States will have the tools necessary to issue NSRpermits addressing condensable PM. Thus, as part ofthe test methods rulemaking, we will take comment on an earlier closing date for the transition period in the NSR
program ifwe are ontrack to meet our expectation to complete the test methods rule much earlier than January 1, 201.1. In the meantime, however, we
are establishing January 1, 2011 as the latest possible end date forthe NSR transition period because this is also the end ofthe transition period for SIP purposes as described in the Clean Air Fine Particle Implementation Rule (see section II.L in 72 FR 20586, April 25, 2007). Prevention of Significant Deterioration and NA NSR permits issued after the effective date ofthis NSR implementation rule but prior to the end ofthe transition period for the NSR program are not required to account for condensable emissions in " PM2. 5 or PM 1 0 emissions limits. After January 1, 2011 (or any earlier date .establishedin the upcoming rulemaking codifying test methods), EPA will require that NSR permits include limits ofcondensable emissions, as appropriate. Prior to this date, States are not prohibited from establishing emissions limits inNSR permits that include the condensable fraction of direct PM2. 5. As noted in the proposal preamble, certain commercial orindustrial activities involving high temperature :processes (e.g., fuel combustion, metal• processing, and process cooking operations) emit gaseous pollutants into the ambient air, some ofwhich rapidly condense into particle form. The constituents ofthese condensed particles include, but are not limited to, organic materials, sulfuric acid, and metals and metal compounds. We consider such condensable emissions to be acomponent of direct PM emissions. Specifically, direct PM emissions consist ofboth the "filterable fraction"' which already exist in particle form at the elevated temperature ofthe exhaust stream, and the "condensable fraction" which exist ingaseous form under exhaust stream conditions but condenses rapidly in the ambient air.

Because condensable PM emissions exist almost entirely inthe 2.5 micrometer range and smaller, these emissions are inherently more. significant for PM2. 5 than for prior PM standards addressing larger particles. Condensable PM emissions commonly make up a significant component of direct PM 2.5 emissions. Therefore, we believe that it is important that the air quality management of PM promote a comprehensive approach to the control ofcondensable PM.

We proposed on November 1, 2005 to clarify that condensable PM emissions mustbe included when determining whether a source is.subject to the major NSR program. We noted in the proposal that our prior guidance 12 had clarified that PMo includes condensable PM and

12 Leter from Thompson G. Pace, Acting Chief, Particulate Matter Programs Branch, to Sean Fitzsimmons, Iowa Department ofNatural Resources (Mar. 31, 1994) (available at http:// www.epa.govfRegion7/programs/artd/air nsr.nsrmemos/cpm.pdf andin the docket for th.is rulemaking, Docket ID No. EPA-HQ-OAR-2003- 0062). 

### 28334Federal Register / Vol. 73, No. 96/ Friday, May 16, 2008 / Rules and Regulations

that, where States expect condensable PM emissions to be inhigher amounts, States should use methods that appropriately measure condensable PM emissions. In addition, we pointed out that the 2001 consolidated emissions reporting rule (CERR) requires States to report condensable emissions in each inventory revision (see67 FR 39602, June 10, 2001) and that Method 202 in appendix M of40 CFR part 51 quantifies condensable PM. We also noted that States have not applied this existing guidance consistently.

Wereceived a number ofcomments

on whether NSR programs should account for condensable PM emissions in. light ofthe current state ofknowledge ofand uncertainties around the measurement of direct PM2.5. Several
commenters supported our proposal to require the inclusion ofcondensable PM emissions in NSR applicability determinations. On the other hand, several other commenters expressed opposition to including condensables at this time and raised concerns about the availability and implementation oftest methods and related issues about the uncertainties in existing data for condensable PM 2. 5 . As a result ofthe
concerns, these commenters believed EPA would be premature inrequiring a comprehensive evaluation of condensable PM 2.5,especially as it related to developing any new emissions limits for stationary sources.

One commenter noted that regulation of condensable PM at this time will impede, rather than facilitate, expeditidus attainment ofthe PM2.5 standard. Another commenter expressed

concern about the poteitial for retroactive enforcement over applicability decisions made in good faith, and forretroactive application of the new test method to assert violations of an emission limit, where the applicability decision or the emission limit was originally based on flawed testing/estimatilg methodology. Several commenters raised serious concerns about the availability and implementation of accurate test methods and emissions factors for condensable PM2.5. They further stated that regulation ofcondensable PM2.5 emissions would be appropriate only after we have developed a workable transitional strategy that ensures existing major sources are not placed in "NSR jeopardy" for physical and operational changes undertaken before

new test methods and other -requirements for condensable PM2. 5 are established.

In recognition ofthese concerns, both

as they apply to the NSR program and the broader air program, we have adopted a transition period during which NSR permits need not address limits ofcondensable PM2.5 emissions. During this transition period, EPA will undertake a collaborative testing effort with industry, National Association of Clean Air Agencies (NACAA), and other stakeholders to assess and improve the. effectiveness and accuracy ofthe available or revised test methods. The purpose ofthe stakeholder testing projects will be to collect new direct filterable and condensable PM2. 5 emissions data using methodologies that provide data more representative of sources' direct PM 2. 5 emissions. The EPA, States, and others will use these data to establish or improve emissions factors and to define more representative source emissions limits in permits.

The EPA acknowledges the legitimate

concerns raised by commenters concerning potential exposure to

- retroactive enforcement and has established rules to address this issue. The EPA will not revisit applicability determinations made in good faith prior to the end ofthe transition period, insofar as the quantity ofcondensable PM emissions are concerned, unless the applicable implementation plan clearly required consideration ofcondensable PM. Likewise, EPA will interpret PM emissions limitations in existing permits or permits issued during the transition period as not requiring quantification ofcondensable PM2. 5 for compliance purposes unless such a requirement was clearly specified in the permit conditions or the applicable 

## .implementation plan. " After the end ofthe transition period (January 1, 2011 or any earlier date established in the upcoming rulemaking codifying test methods), EPA will require that all NSR applicability determinations for PM2. 5 and PM 1 o address condensable emissions as applicable, and the source may not rely

on calculations made for previous determinations that did not include an accurate accounting ofcondensables. Additionally, compliance with these limits must be determined using the promulgated validated test methods that

are applicable after that date. Moreover, after that date, we expect that condensable PM emissions willbe addressed in all other aspects of the major NSR program, such as impact analyses under PSD and offsets under NA NSR. See 72 FR 20586, April 25, 2007 for the discussion ofthe transition period as it applies to the other elements ofthe air program in the final Clean AirFine Particle Implementation Rule. Although EPA is not requiring that State NSR programs address condensable emissions ofPM until the end ofthe transition period, States that have developed the necessary tools ae not precluded from acting to measure and control condensable PM emissions inNSR permit actions prior to the end ofthe transition period, especially if it is required in an applicable SIP. To the
extent that a State has the supporting technical information and test methods, the State may assess the capabilities of
current control technologies, possible modifications to such technologies, or
-new technologies as appropriate relative
to control ofcondensable PM 2.5 emissions. As an example, a specific approach for controlling condensable PM could be a change in control device operating temperature to improve emissions reductions. We also note that it is important that implementation of any new or revised emissions limits and
test 'methods that account for condensable emissions should be prospective and clearly differentiated from existing NSR permit requirements. This will avoid confusion over the compliance status relative to existing PM emissions limits that were not developed considering the condensable portion.

Notwithstanding the issues and uncertainties related to condensable PM, we encourage States to begin immediately to identify measures for reducing condensable PM emissions in major NSR permit actions, particularly where those emissions are expected to represent a significant portion oftotal PM emissions from a sourceF.PreventionofSignificant Deterioration (PSD) Program Requirements

To receive a permit for a new major

source or amajor modification, sources subject to PSD must:

* Install Best Available Control Technology (BACT). * Conduct air quality modeling to

ensure that the project's emissions will
not cause or contribute to either-

-A violation of any NAAQS or

maximum allowable pollutant increase (PSD increment); or -An adverse impact on any Class I area "air quality related value" (AQRV).

e As required, comply with preconstruction monitoring requirements.
This final action regarding each ofthese elements is discussed in the following sections. 

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1. How must BACT be implemented for PM 2.5?

- We arenot making any change to our
current regulations or policy for implementing BACT requirements at a major source that is subject to the requirements ofthe PSD program. Accordingly, ifa new major source will emit, or have the potential to emit, a significant amount ofa regulated NSR pollutant in an attainment area for that pollutant, the source must apply BACT for each emissions unit that emits the pollutant. In addition, ifa physical or operational change at an existing major

source will result in a significant emissions increase and a significant net emissions increase ofa regulated NSR pollutant in an attainment area for that pollutant, the source must apply BACT
to each proposed emissions unit experiencing a net increase in emissions of that pollutant as a result ofthe physical or operational change in the unit. Under the PM2. 5 PSD program, these requirements will apply to direct PM2.5emissions; SO 2 emissions; NOx emissions, unless a State demonstrates that NOx is not a significant contributor to ambient PM2. 5 concentrations in that
area; and to VOC if identified by a State

as a precursor in the PM2.5 attainment

area where the source is located.
2. How does EPA plan to address PM2.5 Increments, Significant Impact Levels (SILs), and Significant Monitoring Concentrations (SMCs)?

On November 1, 2005, we proposed a rule to implement the PM2. 5 NAAQS, including proposed revisions to the NSR program (70 FR 65984). In that proposal,

we indicated our intent to propose a separate rule for developing PM2.5 increments, SILs, and SMCs and sought comments on general approaches for developing these values. We proposed PM2. 5 increments, SILs, and SMCs in a rule dated September 21, 2007. 72 FR 54112. We intend to address comments received on these components ofthe PM2. 5 PSD program when we finalize that proposed rule.
3. What is the ambient air quality analysis requirement for PM 2.5?
All sources subject to PSD review
must perform an ambient air quality impact analysis to show that the emissions from.the source will not

cause or contribute to aPSD increment

or NAAQS violation. See section 165(a)(3) ofthe CAA; 40 CFR 51.166(k) and 52.21(k). We did not propose, and

our final rules do not contain, any changes to the regulations on air quality impact analyses for purposes ofthe PM2. 5 NSR program. Accordingly, sources will be required to perform this analysis for the PM 2. 5 NAAQS and, when finalized, PM2.5 increments. Such analyses must consider how a source, in combination with other sources in the
area, will impact air quality at existing PM2.5monitor locations, as well as at other locations that are appropriate for comparing predictcd PM2. 5 concentrations to the NAAQS based on PM2.5monitor siting requirements and recommendations.

4. How must the PSD preconstruction monitoring requirement be implemented for PM2. 5? Sources subject to PSD are subject to preconstruction ambient air quality monitoring requirements. See sections 165(a)(7) and 165(e) ofthe Act and 40 CFR 51.166(m) and 52.21(m). The PSD permitting requirements provide that continuous preconstruction ambient air quality monitoring must be conducted for any criteria pollutant emitted in significant amounts. Under 40 CFR 51.166(i)(5) and 52.21(i)(5), the reviewing authority has the discretion to exempt an applicant from this monitoring requirement if:

o The maximum modeled concentration for the applicable averaging period caused by the proposed significant emissions increase (ornet emissions increase) is less-than theprescribed SMC; or

o The existing monitored ambient concentrations are less than the prescribed SMC. A source may also use existing data as
a surrogate for preconstruction monitoring if the existing monitored data record is determined to be representative ofthe project's location.

We proposed five options for how to address preconstruction monitoring for PM2.5.We are adopting a combination of options 1 and 3 from the proposal, primarily because we believe that it reflects existing procedures for other regulated NSR pollutants. The following sections summarize the major comments received on each option and explain why we are not adopting particular options. Option 1-Require Preconstruction Monitoring for All Sources But Exempt

on a Case-by-Case Basis

Generally, commenters who supported option I believed the option gives regulatory agencies enough flexibility to address sources with unique characteristics. One
commentator stated that another benefit is that this option would avoid unnecessary installation ofnew PM2.5 monitors and redundant preconstruction monitoring. Another commenter, however, believed option Ito be overly burdensome until EPA develops an SMC. The commenter argued that for example, there are many upcoming PSD projects in their State, which would be located in extremely remote areas where there are no local or regional PM2. 5 emission sources, so there would be no need to collect such data forthese areas. Additionally, one group ofcommenters stated that option 1 appeared to be "streamlining" preconstruction permit requirements, which is not the intention of the Act's PSD provisions, and that EPA does not have the authority to exempt sources from the requirements of section 165(e)(2).

We agree with the "commenterthat recommended combining option 3 (the

use of a 24-hr PM2.5 SMC) with option 1 and are finalizing this approach. We have proposed an SMC for PM2.5 in the rulemaking on increments, SILs, and SMCs (72 FR 54112, September 21, 2007). Our regulations at 40 CFR 51.166(i)(5) and 52.21(i)(5) have allowed the use ofan SMC as screening tool for identifying when an impact is de minimisand there is thus little or no value in gathering preconstruction monitoring data The use of deminimis levels ofthis nature (such as significant emission rates and significant impact levels) is supported by court precedent interpreting the NSR provisfons ofthe Act. AlabamaPowerCo. v. Costle,636 F.2d 323, 360 (DCCir. 1979). ("Unless Congress has been extraordinarily rigid, there is likely abasis for an implication ofdeminimisauthority to provide [an] exemption when the burdens of regulation yield a gain oftrivial or no value.") Option 2-Exempt All Sources From Preconstruction Monitoring

Under option 2, we proposed to exempt all PM2. 5 sources from preconstruction monitoring through a * blanket determination that the existing PM2. 5 monitoring network is sufficient. One commenter who preferred option 5 (described subsequently) was also supportive of option 2. This commenter noted that preconstruction monitoring is expensive and can significantly delay a project. The commenter also pointed out that it is very difficult to locate monitors forboth direct PM2. 5 and precursors because precursors may transport over long distances before transforming into PM2.5. The commenter indicated that we should not rely on the existing regulations, which are already known to be problematic.

One comment letter from a group of environmental advocacy organizations specifically opposed option 2. These 

### 28336Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations

commenters noted that spatial gradients

can be significant forPM2. 5 ,especially for direct PM2. 5 emissions, and that the existing monitoring network is severely limited in its spatial coverage, most especially in attainment areas where PSD preconstruction monitoring requirements apply. The commenters indicated that to make a blanket determination that the existing network suffices for any source, regardless of where it might choose to locate, would be absurd.

We decided not to finalize option 2 because we do not believe that the
current network will be sufficient for all existing and potential new sources. As stated in the proposal preamble, we believe that the existing PM 2. 5 monitoring record has the following limitations:

* The PM 2.5-monitoring data record would require spatial interpolation between monitors for the determination of appropriate concentrations atthe project's location.

* Use ofexisting monitored data will not increase the PM 2.5 monitoring data record to confirm or contradict conventional perceptions.

* The PM 2.5 monitoring data record

assumes that local hot spots ofhigh PM2. 5 concentrations do not exist orare already being monitored, which may not be true in all cases.

.* Automatic acceptance ofexisting
measurements does not follow our current policy that a case-by-case determination needs to be made to determine whether preconstruction ambient monitoring is necessary. * When used with the impact modeling, separate concentrations of direct and precursor-formed PM are needed. Option 3-Use SMC's To Exempt Sources From Preconstruction Monitoring

Several commenters supported this option adding that this approach follows existing procedures tojustify the exclusion ofpreconstruQtion monitoring requirements when source impacts are less than the SMC or when sufficient representative data exists. One group ofcommenters stated that EPA's proposed options 1 and 3, which would allow case-by-case or de minimis exemptions from the monitoring requirements, are ill-conceived as a - matter ofpublic policy and contradict the Act's PSD provisions.

We agree with the commenters that support adopting option 3 because a combination of options 1 and 3 reflects existing procedures for other regulated NSR pollutants. As discussed previously, a de minimisexemption from monitoring requirements is supported by court precedent interpreting the PSD provisions ofthe Act. We do not consider it sound policy to require gathering additional data when it is unnecessary to demonstrate that a proposed source or modification will not adversely impact air quality. Option 4-Use Existing PM10 Data

We proposed using the available large PMo data record combined with the recently acquired PM2. 5 data to provide representative ambient measurements for most sources: One comnient letter from an industry group opposed any requirement for preconstruction monitoring, and endorsed option 4 if nationally gathered PM2.5 data is not available. Three commenters specifically opposed option 4. One comment letter from an environmental advocacy organization stated that option 4 is illegal on its face, to the extent that EPA intends it as a universally available alternative. This comment indicated that some individual sources might be able to demonstrate that PM10 monitoring could fulfill the statutory requirements and purposes ofPM2.5 monitoring (e.g., with sufficiently protective assumptions about PM2. 5/ PM1o proportions), but due to the variability in the relationship between PM2.5 and PM10, EPA cannot categorically allow this substitution. Two other commenters stated that option 4 was not a viable approach due to the convoluted nature ofattempting to infer PM2. 5 concentration from PM10 monitoring data for source-specific applications.

We decided not to finalize option 4. As we recognized in the proposal preamble, the differences in characteristics between PM2. 5 and PM 0 and our limited understanding oftheir relationship are problematic for this application. We do notbelieve that generalized factors to convert PM10 concentrations to PM2.5 concentrations sufficiently reflect important industryspecific and spatially-related characteristics ofPM2.5. In addition, removing altogether the obligation to provide preconstruction PM 2. 5 ambient monitoring data would eliminate industry's contribution to the PM2. 5 data record when source impacts are more than de minimis. Option 5-Exempt Sources From Preconstruction Monitoring if No SMC Is Established

We noted in the proposed rule that the existing regulations at 40 CFR 51.166(i)(5)(iii) and 52.21(i)(5(ii) could be interpreted to allow a reviewing authority to exempt an applicant from preconstruction monitoring for any pollutant for which we have not established an SMC. These provisions state that a source may be exempted from preconstruction monitoring "if * * * the pollutant is not listed in" the list ofpollutants for which SMC have been set.1 3 The original rationale for this exemption is based on the lack of adequate methods for measuring ambient concentrations ofpollutants not

on the list. See45 FR 52709, 52723- 52724. We r~quested comment on this interpretation and any other legal or policy rationale that could support applying the text ofthese provisions to exempt sources from preconstruction monitoring-if we elected not to define

an SMC for PM2 . 5. One commenter stated that option 5 is the most practicable to implement until

an SMC can be established and any potential gaps in the monitoring network can be filled. Two commenters question the legality of option 5 under the Act. They added that whatever may have been the case when the existing list of SMCs was adopted, methods now exist for conducting the monitoring required under section 165(e)(2). We decided not to finalize option 5, and have proposed an SMC rule for PM2.5.

In conclusion, we are finalizing a combination ofoptions 1 and 3 from the proposal, since we believe that it reflects existing procedures for other regulated NSR pollutants. Once we finalize an SMC forPM 2.5,the reviewing authority will have the discretion to exempt a source frofh the preconstruction monitoring requirement ifthe projected PM2. 5 ambient impact of the source is below the PM 2.5 level promulgated in our rules. In addition, additional preconstruction monitoring data may not be necessary based on the availability ofexisting representative monitoring data in the area, as discussed previously.
G.Nonattainment New SourceReview (NA NSR) Requirements

To receive a permit for a new major

source or a major modification, sources subject to NA NSR must:

* Install Lowest Achievable Emission Rate (LAER) control technology;

* Offset new emissions with creditable emissions reductions;

13 These sections actually cross-reference the list

at 40 CFR 51.166(i)(8)(i) and 52.21(i)(8(i), however

we renumbered those paragraphs to paragraph (i}{5)(i) ofthose provisions in the December 31, 2002 NSR reform rule and inadvertently overlooked correcting the cross-references in paragraphs (i)(5)(ii) and (il(5)(iii). See 67 FR 80186. As proposed, in this final action we have corrected this misnumbering and others in this section. 28337Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations



### * Certify that all major sources owned

or operated by the applicant in the same State are in compliance; and * Conduct an alternative siting analysis demonstrating that the benefits of the proposed source significantly outweigh the environmental and social
costs. We did not propose, nor are we finalizing, any revisions to the first, third, and fourth ofthese requirements. Thus, these requirements apply for
purposes of PM2. 5 and its designated precursors just as they apply for other criteria pollutants and their designated precursors. In the remainder of this section G, we discuss our final actions related to offsets for direct PM2.5 emissions and emissions ofPM 2. 5 precursors.
1.What is the required offset ratio for direct PM2.5 emissions?

Under section 173 of the Act, all major sources and major modifications at existing major sources within a nonattainment area must obtain emissions reductions to offset any emissions increases resulting from the project in an amount that is at least equal to the emissions increase, aid that is consistent with reasonable further progress towards attainment. We refer to the proportional difference between the amount ofthe required offsets to the
amount ofemissions increase as the "offset ratio."

The Act specifies an offset ratio for several situations. In ozone nonattainment areas subject to subpart 2 (oftitle I, part D ofthe Act), the ratio is set between 1.1:1 and 1.5:1 depending

on the area's level ofclassification pursuant to subpart 2. For other nonattainment areas, the Act establishes

a minimum offset ratio of 1:1 pursuant to subpart 1 oftitle I, part D of the Act.

As proposed, we are finalizing the offset ratio for direct PM2.s emissions as at least 1:1 on amass basis because the PM2. 5 program is being implemented under subpart 1 of the Act. The
commenters on this issue generally agreed that our regulations should require an offset ratio of at least 1:1 pursuant to subpart 1.

A few commenters indicated that a lower ratio could be acceptable on a source-specific basis if accompanied by

a modeling analysis demonstrating a net air quality benefit. One commenter suggested that such a demonstration wouldbe possible when a direct PM2.5 emissions increase from a tall stack is being offset by ground-level PM2. 5 emission reductions. Applying diesel retrofit technology to bus and truck fleets is an example ofhow ground-level PM2.s emission reductions could be achieved. We do not believe that a lower offset ratio is authorized under subpart 1, which prescribes an offset ratio ofat least 1:1, and therefore we have not adopted this approach in our final rules.

Some ofthe commenters disagreed regarding whether an offset ratio ofat least 1:1 under subpart 1represents a ceiling or a floor on the level we can prescribe in our regulations. We interpret section 173 ofthe Actto allow higher offset ratios where necessary to achieve reasonable further progress. Accordingly, We believe that States may establish higher offset ratios in their State programs ifthey wish, but we do
notbelieve that it wouldbe appropriate for us to do so for PM2.sin national regulations. We do not have cause to believe a higher ratio is necessary for PM 2.5 in each area ofthe country and prefer to leave this to the discretion of States. We do notbelieve that the higher offset ratios required for ozone precursors under subpart 2 apply in any way to direct PM2. 5 emissions or PM 2.5 precursors. 2. Which precursors are subject to the offset requirement?

- Consistent with our proposal, the pollutants that are designated as PM 2 .- precursors-in a particular area are subject to the offset requirement in that

area. Accordingly, SO 2 is subject to offsets in all PM 2.5nonattainment areas. As a "presumed-in" precursor, NOx will be subject to offsets unless a State obtains an exemption for-its NSR program through a demonstration that NOx emissions ina particular area are not a significant contributor to ttiat area's ambient PM 2. 5 concentrations. As "presumed-out" precursors, VOC and ammonia would be subject to offsets only in areas where the State has demonstrated thatthese emissions are significant contributors to the area's ambient PM2.s concentrations. Two commenters on this issue agreed with this approach; one commenter recommended that we not require offsets for any PM2 5 precursors. We believe that it is appropriate to offset emissions increases ofall precursors that have been established to contribute
to the PM 2.snonattainment problem in

a particular area. 3.What is the required offset ratio for
PM2.5 precursors?

As discussed previously, the Act requires that a source obtain offsets for emissions increases that occur in a nonattainment area. As with PM2.5 direct emissions, the minimum offset ratio permitted under subpart 1 ofthe Act is at least 1:1. Based on these requirements ofthe Act, we are finalizing our proposal that an offset ratio of at least 1:1 applies where a
source seeks to offset an increase in emissions ofa PM2. 5 precursor with creditable reductions ofthe same precursor. This offset ratio applies for all pollutants that have been designated

as PM2.5precursors in a particular nonattainment area.

Most commenters agreed with this approach. A few commenters indicated that an offset ratio ofless than 1:1 for
precursor emissions of PM 2.5 should be allowed only ifthere is a net air quality benefit and if the lower ratio isjustified by air quality modeling analysis. They noted that for PM2.5 precursors, chemical reactivity modeling demonstrations should be developed and approved that are, at a minimum, capable ofdetermining the impacts of the precursor emissions on tl~e air quality in the nonattainment area in which the source is located. As noted previously, we do notbelieve that any offset ratio less than 1:1 is permissible under subpart 1.

One commenter stated that consistent with the statutory scheme for ozone laid
out in section 182, and given the severity ofthe health risks associated with PM2.5,EPA mustrequire offsets of

at least 1.15:1 for PM2.sprecursors in "moderate" nonattainment areas, and
must increase the offset ratio in "serious" nonattainment areas or in

areas that request extensions oftheir attainment deadlines. As mentioned previously, we do not believe that subpart 2 ofthe Act (which includes section 182) has any relevance to PM 2.5
or its precursors. Subpart 2 is specific to

ozone. In addition, we are implementing the PM 2 .5 program under subpart 1. Nevertheless, under the Act, we believe that a State may require higher offset ratios if it determines that they are necessary to achieve reasonable further
progress. For the reasons discussed previously with respect to direct PM2. 5 , we do not believe that it is appropriate for us to set higher offset ratios for PM2.5 precursors on a national basis.

Two commenters requested that we make clear in the final rule that an increase in precursor emissions need only be offset once, even if the increase triggers nonattainment NSR under, for example, both the ozone and PM2.5 programs. We agree with these
commenters and are clarifying that a precursor emissions increase only needs
to be offset once. A permit applicant will not, for example, need to obtain
two sets ofoffsets for NOx emissions if NOx is regulated as a precursor both for

ozone and PM2.s in the area. The NOx
precursor emissions need only be offset

once in accordance with the applicable 

### 28338Federal Register/Vol. 73, No. 96/Friday, May 16, 2008 /Rules and Regulations

ratio. To the extent a higher ratio applies for ozone under subpart 2, the applicant would have to obtain offsets at the higher ratio. However, when the offset ratios are the same, both requirements can be met with a single set ofNOx offsets.

4. Is interpollutant trading allowable to comply with offset requirements?

In this final rule, we are allowing limited interpollutant trading for purposes ofoffsets only (and not netting) under the PM2.5 NA NSR program. Specifically, the final rules allow interpollutant trading only based

on a trading ratio established in the SIP

as part of the attainment demonstration approved for a specific nonattainment
area, on a statewide basis, or in a regional, multi-state program. This differs from our proposal in that the final rules do not allow interpollutant trading on a case-by-case basis as part of

an individual NANSR permitting process. For the purpose ofoffsets in the NA NSR program for PM2. 5,the final rules"allow reductions in directPM 2 .

5 emissions to offset precursor emissions increases, emissions reductions of one precursor to offset emissions increases ofanother precursor, and reductions in precursor emissions to offset direct
.PM 2. 5 emissions increases. We have completed a technical assessment to develop preferred interpollutant trading ratios that may be used for the purposes of PM 2.5offsets, where appropriate. The preferred ratios

were generated with a PM2.5 response surface modeling (RSM) approach based

on the EPA's Community Multi-Scale Air Quality (CMAQ) model. This RSM approach allows one to distinguish the impact ofdirect and precursor emissions from particular source groupings on total PM2. 5 concentrations within nine specific urban areas and broadly across U.S. regions. This approach Was recently applied by the Agency to inform development of potential PM 2 .s control strategies as part of the Regulatory Impact Assessment (RIA) for the final PM 2.5NAAQS.1 4
Based on results from the RSM, we determined the distribution ofpredicted ratios for urban areas and regions across the country and developed the preferred ratios with agoal to be environmentally protective. The technical approach with details on data and modeling inputs are fully described in a technical memo to the docket, "Details on Technical Assessment to Develop Interpollutant

14 A full description of this approach is available in the technical support document at http://www. epa.gov/scramool/repoils/pmnaaqs-tsd rsm-alL 021606.pdfand in the docket for this rulemaking, Docket ID No. EPA-HQ-OAR-2003--0062. Trading Ratios for PM2.sOffsets." 15 Use ofthe preferred ratios is recommended by EPA but not mandatory, and we do not intend to preclude the opportunity for a local demonstration oftrading ratios on a case-by-case basis and public input into that process.

Our work here and in other recent PM2. 5 assessments clearly show that the relative efficacy ofemissions reductions varies across pollutants and that a ton ofdirect PM2.5 is generally more effective than a ton ofprecursor emissions in reducing overall PM 2.5 concentrations. For the purposes of reporting information here, we define the "East" to be the 37 States either completely or in part east of100 degrees west longitude. "West" would include the remaining 11 western-most States in the continental United States. We found the following relationships between pollutants in developing the preferred trading ratios:

1.NOx to S0 2. S0 2 to NOx: Our assessment indicated potential disbenefits of reducing NOx (i.e.,.reducing NOx tons in urban areas may increase overall PM 2.5 concentrations) in the eastern United States andurban areas inthe western United States. Dueto thepossibility ofthese disbenefits and thehigh degree ofvariability inthe observed NOx to SO 2ratios or SO2 to NOx ratios across urban areas, we are not defining preferred ratios involving trades between these precursors but will relyupon a local demonstration to determine the appropriate trading ratios.

2. NOx to Primary PM2 .5; Primary.PM2.5 to NOx: Based on a local demonstration that NOx reductions are beneficial in reducing
PM 2. 5 concentrations (i.e., no disbenefits from NOx reductions asnoted previously), our assessment indicates that the preferred

- trading ratio is 200 to 1 (NOx tons for PM2 . 5 tons) or 1to 200 (PM2. 5 tons for NOx tons) for areas in the eastern United States, and 100 to 1(NOx tons for PM 2. 5 tons) or 1 to 100 (PM 2 .

5 tons for NOx tons )for areas in the western United States.

3. SO 2 to Primary PM 2.s; Primary PM2 . 5 to SO2 :We have determined a nationwide preferred ratio of40 to 1 (SO 2 tons for PM 2

_ 5 tons) or.1 to 40 (PM 2 .stons for SO 2)for trades between these pollutants. We recognize there is spatial variability here between urban and regionally located sources ofthese pollutants that can be addressed through a local demonstration to detqrmine an area-specific relationship, as appropriate.

We recommend that States hse thiese hierarchies and trading ratios in their interpollutant trading programs to provide consistency and streamline the trading process. As indicated by our work and findings, it is appropriate to establish acceptable trading ratios for interpollutant trading forPM2:5 NSR offsets. If States elect to'use EPA's

15 Available in the docket for this rulemaking, DocketID No. EPA-HQ-OAR-2003-0062. recommended trading ratios, they may rely on EPA's technical work and a presumption that such ratios will be approvable by EPA absent a credible showing that EPA's trading ratios are not appropriate for that location. If States choose to develop thEir own hierarchies/trading ratios, they will have to substantiate by modeling and/or other technical demonstrations ofthe net air quality benefit for PM 2. 5 ambient concentrations, and such a trading program will have to be approved by EPA.

We acknowledge that the relationship between pollutants can vary across geographic areas. Thus, local demonstrations, to determine trading ratios, will need to address anumber of local factors including, but not limited to, the following:

1.The relative magnitude of emissions of direct PM2. 5 and precursor gases (e.g., SO 2 andNOx) within the geographic area of
interest.

2.The relative contribution to local PM2 .5 nonattainment of directly emitted PM2. 5 and individual precursors from the various

sources or source categories under consideration as part of a potential interpollutant trade.

3.The meteorological conditions and topography ofthe area, which result in different source-receptor relationships across pollutants within the local area.

We.have adopted this approach to capture the flexibility advantages.of interpollutant trading, while remaining mindful ofthe limitations of existing air quality models. We believe that the regional-scale models used for areawide attainnient demonstrations have sufficient accuracy to establish an overall equivalence ratio for a nonattainment area. However, we do not believe that available models can accurately determine the effects of interpollutant trades'at a single source. In addition, permit-by-permit modeling demonstrations are extremely resource intensive, dnly to yield limited results. For these reasons, the final rules only allow a State to develop its own interpollutant trading rule forinclusion in its SIP, based on a technical demonstration for a specific nonattainment area. We will not accept case-by-case demonstrations on an individual source permit basis.

The flexibility provided by this policy allows sources to select the most costeffective manner to obtain the offsets necessary to ensure that PM2. 5 air quality improves. This willbe particularly beneficial where offsets for

one particular pollutant are scarce in a particular area, as is often the case for direct PM2. 5 emissions and SO 2. 

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### Federal Register/Vol. 73, No. 96/Friday, May 16, 2008/Rules and Regulations

We received a large number of comments on this issue representing a wide variety ofviewpoints. Several
commenters supported flexible interpollutant trading atratios established either on an area-wide basis

or permit by permit. They often pointed out the economic and administrative benefits offlexibility in the program, especially in areas where offsets for

some pollutants will be difficult to obtain. One commenter asserted that such flexibility is essential to the ability ofenterprises to be able to expand as the PM2. 5 NAAQS is implemented, especially in the program's early years. Another commenter suggested allowing such trading on an equal basis, without the "unnecessary complication" of interpollutant offset ratios.

Many commenters argued against allowing interpollutant trading for offsets. These commenters commonly pointed out that direct PM2.5emissions typically have amore local impact, while the impact ofprecursor emissions

are farther afield. A number of commenters pointed out the complex atmospheric chemistry ofsecondary particulate formation and the shortcomings ofthe air quality models currently available to perform a.detailed PM2. 5 formation assessment, specifically that local-scale.models are not sufficiently accurate and regional-scale models do not have the resolution to show local impacts adequately. According to two commenters, trading precursors for direct PM 2.5 emissions raises serious environmental justice

concerns due to the localized impacts of direct PM2 .semissions. These commenters also asserted that the equivalence between precursors would vary spatially and temporally, making it extremely difficult to assess, and that PM2. 5 precursors also differ in their impacts on other air pollution problems, such as direct health and welfare impacts ofSO 2 and NOx; and formation ofozone, acid deposition, and reactive nitrogen deposition.

We also received comments opposing allowing interpollutant trading for netting purposes, on the basis that the resulting program wouldbe very staffintensive apart from the difficulty of demonstrating through modeling the net air quality benefit ofa single source trade. We concur with these commenters and are not allowing interpollutant trading for netting purposes at this time. A number ofcommenters supported

some types oftrades, but not others. Most frequently, these commenters favored allowing reductions in direct PM2. 5 emissions to offset precursor emissions increases. One commenter suggested a hierarchy as follows: Direct PM2.5 emissions, S02, NOx, ammonia, and VOC. That is, apollutant should be allowed as an offset for a pollutant ranked lower, but not the-reverse (e.g., reductions in direct PM2. 5 emissions could be used to offset increases in any ofthe listed pollutants, SO 2 emissions reductions could offset NOx increases, etc.).

As previously noted, this rule allows interpollutant and interprecursor trading of offsets according to a SIPapproved trading program. To be approved, the trading program must either adoptEPA's recommended trading ratios orbe backed up by regional-scale modeling that demonstrates anet air quality benefit using appropriate overall offset ratios for such trades for a specified nonattainment area, State, or multi-State region. There is considerable uncertainty about the relationship of precursor and direct PM2.5 emissions to localized ambient PM2. 5 concentration both spatially and temporally. Given the uncertainty as tO localized adverse and beneficial effects, we have opted for program flexibility. We believe this is necessary, in part, because of the shortage of available offsets for some pollutants, particularly direct PM2.5 emissions and SO 2,in many areas.
H. How will the transitionto thePM2.5 PSD requirementsoccur?
1. Background

On October 23, 1997, after the NAAQS for PM2. 5 was originally promulgated, we issued a guidance document entitled "Interim Implementation for the New Source Review Requirements for PM2. 5," John S. Seitz, EPA. As noted in that guidance, section 165 of the Act suggests that PSD requirements become effective for a new NAAQS upon the effective date ofthe NAAQS. Section 165(a)(1) of the Act provides that no new or modified major

source may be constructed without a PSD permit that meets all ofthe section 165(a) requirements with respect to the regulated pollutant. Moreover, section 165(a)(3) provides that the emissions from any such source may not cause or contribute to-a violation ofany NAAQS. Also, section 165(a)(4) requires BACT for each pollutant subject to PSD regulation.

The 1997 guidance stated that sources should continue to use implementation ofa PM 1o program as a surrogate for meeting PM2. 5 NSR requirements until certain difficulties were resolved, primarily the lack ofnecessary tools to calculate the emissidns ofPM2. 5 and related precursors, the lack ofadequate modeling techniques to.project ambient impacts, and the lack ofPM 2 .

5 ' monitoring sites. With this final action and technical developments in the interim, these difficulties have largely been resolved.

2. Transition for "Delegated States"

The Federal PSD program is contained in 40 CFR 52.21. This section is the Federal implemeritation plan for

areas lacking an approved PSD program. We implement this program in Indian country and some U.S. territories, but for the most part we have delegated implementation of40 CFR 52.21 to those States without approved PSD programs (typicallyreferred to as "delegated States;'). Except asprovided in the grandfathering provisions that follow, these final rules go into effect and must be implemented beginning on the effective date of thisrule, July 15, 2008 in all areas subject to 40 CFR 52.21, including the delegated States.

Consistent with 40 CFR 52.21(i)(1)(x), wherein EPA grandfathered sources or modifications with pending permit applications based onPM from the PM1o requirements established in 1987, EPA will allow sources or modifications who previously submitted applications in accordance with the PMo surrogate policy to remain subject to that policy for purposes ofpermitting ifEPA or its delegate reviewing authority subsequently determines the application

was complete as submitted. This is contingent uponthe completed permit application being consistent isith the requirements pursuant to the EPA memorandum entitled "Interim Implementation of New Source Review Requirements for PM2. 5" (Oct. 23, 1997) recommending the use of PM 0 as a surrogate for PM2. 5. Accordingly, we have added 40 CFR 52.21(i)(1)(xi) to reflect this grandfathering provision.
3. Transition for "SIP-Approved States"

The requirements for State PSD programs arecontained in 40 CFR 51.166. Most States have developed PSD programs according to these requirements, which we have approved into each State's implementation plan. States with PSD programs approved under 40 CFR 51.166 are called "SIP-- approved States."

States with SIP-approved PSD programs that require amendments to incorporate these final NSR rule changes for PM2. 5 will need time to accomplish these SIP amendments. For example, a State may need to amend its existing regulations to add the specific significant emissions rate for PM2. 5 or a designated precursor. In our December 31, 2002 Federal Register notice 

### 28340Federal Register / Vol. 73, No. 96/Friday, May 16, 2008 / Rules and Regulationspromulgating other changes to the NSR program, we explained that the Act does
not specifically address the timeframe by which States must submit SIP revisions when we revise the PSD and NA NSR rules. W6nonetheless looked
.to section 110(a)(1) to guide our decision to require States to adopt and submit plan revisions within 3 years from when we publish changes in the Federal Register. We codified this approach in the PSD regulations at 40 CFR 51.166(a)(6)(i) and applied this

same timeframe to State NA NSR programs through that finalrule action. .64 FR 80241. This rule follows our established approach for determining when States must adopt and submit revised SIPs following changes to the NSR regulations, but does not revise otherwise applicable SIP submittal deadlines. Accordingly, we are requiring States with SIP-approved PSD programs to submit revised PSD programs and revised NA NSR programs for PM2 .5 

### (see section V.I.) within'3 years from the date ofthis action.1 6

During this SIP development period, the PM2.5 NAAQS must still be protected under the PSD program in such States. We are finalizing our proposed option 1that ifa SIP-approved State is unable to implement a PSD program for the PM2.5NAAQS based on these final rules, the State may continue
to implement a PM1o program as a surrogate to meet the PSD program requirements for PM2.5pursuant to the 1997 guidance mentioned previously. Under option 1for SIP-approved States,

we had proposed two additional requirements. These were to require

sources to demonstrate that emissions from constiuction or operation ofthe facility will not cause or contribute.to a violation ofthe PM2.5NAAQS'and to include condensable PM emissions in

6 1n our proposal, we proposed April 5, 2008 as
a deadline for States to comply with the revised nonattainment NSR and PSD requirements in this rule. However, in light ofthe time it has taken to complete this final rule, expecting States to submit required SIPrevisions consistent with this final rule by April 5, 2008 is no longer practical or fair. Nevertheless, States are still cugrently required to implement a PSD program for PM2.s, and we still expect States to fulfill the SIP infrastructure requirements ofCAA section 110(a)(2), including the PSD program requirements, by April5, 2008. Webelieve these PSD program requirements are currently met by implementing the transitional PSD
program for PM2. 5 described in this preamble (ak..a. the PM 1 0 surrogate policy). In accordance with a Consent Decree in Environmental Defense and American LungAss'n v.Johnson,No. 1:05CV00493 (D.D.C. June 15, 2005), EPA must determine by October 5, 2008 whether each State has submitted the SIP revisions for thePM2.5PSD program required under section 110(a)(2) ofthe Act. This rulemaking does not change the specific guidance

we previously provided to States on what they should submit by April 5, 2008 to comply with section 110(a)(2). determining major NSR applicability and control requirements. We are not finalizing either ofthese additional requirements of our proposed option 1.- We have dropped the requirement for demonstrating compliance with the PM 2.5NAAQS in order to maintain consistency in the application ofthe existing surrogate policy across the PSD program during the interim period. Since in the final rule we are otherwise allowing SP-approved States to continue with the existing PM10 surrogate policy to meet the PSD requirements forPM2. 5, partially implementing the PM1o surrogate policy in this manner would be confusing and difficult to administer. Thus, to ensure consistent administration during the transition period, we have elected to maintain our existing PM 1osurrogate policy which only recommends as an interim measure that sources and reviewing authorities conduct the modeling necessary to show that PM~o emissions will not cause a violation of the PM1oNAAQS as a surrogate for demonstrating compliance with the PM2.5 NAAQS. Also as discussed previously in section V.E, we are not requiring condensable emissions to be fully integrated into the PM2.5program until the end of the transition period to. validate test methods discussed in section V.E ofthis preamble.

In our proposal, we offered two additional option for the SIP development period in-States with SIPapproved PSD programs. Under option 2, we would have updated the 1997 guidance to reflect the provisions in these final rules and allowed States to

run a PM2. 5 program pursuant to this updated guidance. Alternatively under option 2, we would have amended appendix S and 40 CFR 52.24 so that the PSD requirements of40 CFR 52.21 would govern the issuance ofmajor NSR permits during the SIP development period. Finally, under option 3, we would have allowed a State to request delegation ofjust the Federal PM2. 5 PSD program in 40 CFR 52.21 in that State. A State that otherwise had a SIPapproved PSD program could have requested delegation for PM2.sby informing us that it did not intend to submit a PSD SIP for PM2.5in the immediate future.

We received several comments supporting option 1, although some of these commenters requested that we not require condensable emissions to be included until the c6ncerns with test methods were resolved. One ofthese
commenters favored continuing to implement the PMmo program as a surrogate under the 1997 guidance to provide clarity and certainty to the permitting agency and regulated community. The commenter indicated that PM2. 5 inventories and methods for estimating emission rates are rudimentary and may even be nonexistent in some.cases, which would nmke permitting onerous.

A few commenters opposed option 1. One of these commenters indicated that

we should not continue outdated policy (i.e.,the 1997 NSR guidance) because it does not address'the PM2. 5 problem,
cannot be implemented in some States, and does not incorporate precursor emissions.

Four commenters expressed support for option 2. Three ofthese suggested that we issue updated guidance to incorporate these PSD requirements for PM2. 5, while one preferred that we revise appendix Sto point to the requirements of 40 CFR 52.21. We received one comment in favor of option 3 and three-opposed.

Two commenters supported approaches different from our options. One ofthese commenters requested that the interim framework should, at a minimum, ensure that any new or modified project that exceeds thresholds

use BACT. The commenter also

-suggested that we require offsets for projects approved before the other protective elements ofthe full PSD program are in place to ensure that there is no significant deterioration in air quality. Another commenter stated that

none ofthe proposed options were viable for their State. The commenter requested that we allow States to continue their existing PMo program as

asurrogate forPM2.5,without caveat.

As noted previously, we are finalizing proposed option 1, without the requirement of demonstrating compliance with the PM2s NAAQS or the requirement to include condensable emissions. We believe that our final rule is reasonable for the following reasons. First, PMio will act as an adequate surrogate for PM2. 5 in most respects, because all new major sources and major modifications that would trigger PSD requirements forPM2.5would also trigger PM1o requirements because PM2.s is a subset ofPM10 . Second, both ofthe.
precursors designated in the final ruleSO 2 and NOx (presumptively)-are already regulated under State NSR
programs for other criteria pollutants. Thus, those precursors will be subject to NSR through those otherprograms. We do not believe that the other options or suggestions offer significant advantages that outweigh the utility and ease of implementation ofthis approach.

States may include grandfathering provisions similafto the ones EPA 

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included in the transition requirements for 40 CFR 52.21.

L How willthe transition to the PM 2.

5 NA NSR requirementsoccur?

1. Background

The requirements for State NA NSR programs are contained in 40 CFR 51.165. All States with nonattainnent

areas have developed NA NSR program according to these requirements, which

we have approved into each State's implementation plan. However, as noted previously, it takes time fora State to amend its SEP when it must make changes to its NA NSR program. According to the provisions of 40 CFR 52.24(k), during such an interim period when a State lacks an approved NA 1IS program for a particular pollutant, appendix S of40 CFR part 51 applies ft NA NSR permitting.'

Section 172(c)(5) of theAct requires that States issue major NSR permits for construction and major modifications o major stationary sources in any nonattainment area. Thus, since the PM2. 5 nonattainment designations became effective on April 5, 2005, StatE

are now required to issue major NSR permits that address the section 173 NY NSR requirements for PM2.5.

On the date that the PM2. 5 nonattainment designations took effect (April 5, 2005), we issued guidance to address implementation ofthe NA NSR program pending the completion of thi, action to develop implementation rules forPM2. 5. See memorandum from Stephen D. Page, Director, Office ofAir Quality Planning and Standards to Regional Air Directors, "Implementatio ofNew Source Review Requirements in PM2. 5 Nonattainment Areas" (April 5, 2005).

Our current guidance permits States
to implement aPM1oNA NSRprogram
as a surrogate to address the requirements ofNA NSR for the PM2. 5 NAAQS. A State's surrogate major NSR
program in PM2.5 nonattainment areas may consist of either the implementation of the State's SIPapproved NA NSR program forPM1 oor implementation of amajor NSR prograr for PM10 under the authority in 40 CFR part 51, appendix S.
2. Transition

With this finalization of the new PM 2.5 NSR implementation requirements under 40 CFR 51.165, States now have the necessary tools to implement a NA NSR program forPM2. After the effective date ofthe amended rule (that is,July 15, 2008, States will

no longer be permitted.to implement a NA NSR program for PM1oas a surrogat forthe PM2. 5 NA NSR requirements. Most States will then need to implemeni

atransitional PM2.5NA NSR program under appendix S (as amended in this rulemaking action) until EPA approves changes to a State's SIP-approved NA NSR program to reflect the new requirements under 40 CFR 51.165. At this time, we do notbelieve it is

s appropriate to allow grandfathering of pending permits being reviewed under the PM10 surrogate program in nonattainment areas, mainly because of

a State's obligations to expedite attainment and the fact that we had not established a similar precedent for transitioning from PM to PMio.

The NA NSR provisions in a State's
R existing SP-approved NA NSR program would also apply in areas designated as )r nonattainment for the PM2.5 NAAQS if the SP-approved regulations contain a generic requirement to issue part D permits in areas designated as f nonattainment for any criteria pollutant and do not otherwise need to be amended to incorporate the changes finalized in this action. States belonging
!s to the following categories will need to revise their NA NSR regulations and submit them to EPA for incorporation into the SIP within 3 years fromthe datc ofthis action 17:

* States that have nonattainment regulations which need to be amended to incorporate the new PM2. 5 requirements.

* States that have designated nonattainment areas for PM2.5 and their nonattainment NSR regulations specifically list the areas in which NA

n NSR applies (i.e.,the list does not include the designated nonattainment

areas forPM2.5).

* States that have not previously had nonattainment areas but now have nonattainment areas for PM2.5;

These States will have to implement

a transitional NA NSR permitting program for PM2.5 pursuant to 40 CFR 52.24(k) and appendix S until their existing part D SlPs are revised to meet

17

As discussed earlier, we are following the precedent we established in our 2002 rule for NA n2 NSR program revisions to allow States adequate time to adopt these revisions. For practical and fairness reasons, we are not requiring the NA NSR elements ofthis rule to be submitted by April 5, 2008, as we had proposed. However, the States are still required to submit nonattainment plans for PM

2 .

5 (including NA NSR programs) on April 5, 2008. We believe thisrequirement is satisfied by implementing the transitional NA NSR program for PM2 .5 (a.k.a. the PM,Q surrogate policy) described in

ourApril 5, 2005 guidance, or, ifsubmitted after 5. the effective date ofthis rule, implementing Appendix S as revised in this rule.This rulemaking does not change the specific guidance we previously provided to States on what they should submit to EPA by April 5, 2008 tocomply with

.e nonattainment area requirements under Part D. these new PM2.5 NSR requirements t under 40 CFR51.165.
3. Implementation ofNSR Under the "Emissions Offset Interpretative Ruling" (40 CFR Part 51, Appendix S)With Revisions

In general, appendix S requires new

or modified major sources to meet LAER and obtain sufficient offsetting emissions reductions to assure that a
new major source or major modification of an existing major source willnot interfere with the area's progress toward attainment. Readers should refer to appendix S for a complete understanding ofthese and other appendix S requirements. In this action,

we are finalizing our proposed revisions
to appendix S to include provisions necessary to implement a transitional NA NSR program forPM2. 5 ,including significant emissions rates applicable to major modifications forPM 2. 5 and, as appropriate, precursors. Additionally, since we are finalizing interpollutant trading provisions in the NSR rules at 40 CFR 51.165, we are also amending appendix S to allow interpollutant trading forPM2. 5 . Appendix S applies directly to new and modified major stationary sources. In accordance with the requirements ofsection 110(a)(2)(c) of the Act, we believe that the majority of States have the legal authority to issue permits consistent with these requirements under an existing SIPapproved permitting program. Nonetheless, at least one State has reported that it lacks the legal authority
to issue permits implementing the requirements of appendix S under its existing permitting rules.

Ifa State is unable to apply the requirements ofappendix S, we will act

as the reviewing authority for the relevant portion ofthe permit. We -believe that it is appropriate forEPA to issue the preconstruction permits in such circumstances. Congress amended the Act in 1990 to remove the requirements that would have applied a construction ban in areas that lacked a SIP-approved part D permit program. Thus, we believe that it is consistent with Congressional intent that either the State or EPA issues construction permitsfor those projects meeting the applicable criteria during the interim period. See the preamble ofthe proposal forthis rule for more detail on the legal basis for requiring States to issue NA NSR permits pursuant to appendix S during the SIP development period (70 FR 66045-46).

We received three comments supporting the issuance ofNA NSR permits under appendix S during the.
SEP development period. Two ofthese 

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commenters expected States generally to be able to do so, while one suggested that EPA issue such permits because States will lack the authority to do so without protracted rule revisions. One of these commenters also suggested that

we revise appendix S to authorize interprecursor trading during the transition period, believing that the paucity ofexisting direct PM2. 5 emissions and SO 2 offsets likely will make business expansion in PM 2 . 5 nonattainment areas from now until at least April 2008 impossible unless this is done. One commenter suggested that

we suspend the 2005 PM2. 5 NSR guidance which allows use of PM 1o. emissions'as a surrogate for PM2.5 emissions in PM 2.5 nonattainment areas when we adopt the final PM2.5 implementation rules, while three other
commenters requested continued implementation ofthat guidance during the interim period.

As noted previously, this final action will require States to amend their NA NSR programs consistent with the amended rules at 40 CFR 51.165. During the SIP development period, where they have legal .authorityto do so, States
must issue NA NSR permits under appendix S (as revised for purposes of, the PM 2.5 program). To address one of the points raised by commenters, we are amending appendix S to allow interpollutant trading for PM2. 5 in this final rule. Where a State determines that it does not have legal authority to issue such permits, we will act as the reviewing authority. As ofthe effective date of this action, the 2005 PM2. 5 NSR guidance on use ofPM10 emissions as a surrogate forPM2.5 emissions will remain in effect only for PSD in the SIPapproved States during the SIP development period. In the delegated PSD States and in nonattainment areas, the new PM2. 5 requirements will apply immediately on the effective date ofthig final action.

J.

DoesmajorNSR apply toPM2. 5 precursors duringtheSIPdevelopment period?

As discussed previously in section V.A,we have taken final action on NSR applicability forPM2.5precursors. Specifically, we have designated SO2 as
a national precursor to PM2. 5 in all
areas, NOx as a "presumed-in" precursor in all areas, VOC as a "presumed-out" precursor in all.areas, and ammonia as a "presumedrout" precursor. Thus, States have the option of bxcluding NOx as a precursor by demonstrating that NOx emissions are not a significant contributor to ambient PM2. 5 concentrations in a particular

area. In addition, States have the option ofidentifying VOC and/or ammonia as precursor(s) by demonstrating that emissions ofVOC and/or ammonia are
a significant contributor in an area, and thus should be subject to major NSR.

In the proposal, during the SIP development period, we proposed that SO2 should be treated as a regulated PM2.5 precursor as ofthe effective date ofthis final rule since there is no doubt about its status as such in any area and proposed to defer NSR applicability for NOx until a State SIP ubmittal so that ifa State elected to submit information
to rebut the presumption that NOx is a regulated PM2. 5 precursor, the State would have an opportunity to do so in its SIP submittal. We also proposed that VOCs and ammonia would not be treated as PM2. 5 precursors.during the interim periodbecause they are presumed not to be precursors until they have been demonstrated to be through a State's SIP submittal.

A few commenters supported staying the applicability ofNSR to all precursors during the interim period. However, two of these supporters suggested that EPA establish mechanisms for interpollutant trading for offsets during the interim period so that increases in direct PM 2.5 emissions

can be offset with SO 2 or NOx emissions reductions. Another supporter noted that their State cannot impose obligations on NSR applicants until those obligations are established in State regulations or statutes. Another indicated that this delay would allow States the time to develop experience and knowledge in establishing local photochemical models and to performance test their accuracy.

Two commenters opposed staying

- NSR applicability for any precursors. They believe that this would make attainment more difficult. One commenter suggested that S02 should be designated as a precursor during the interim period, and another suggested the same for S02 and NOx.

Based on the comments, we have been persuaded that SIP-approved PSD States will not have the authority to regulate PM2. 5 precursors before they have amended thefr SIPs to incorporate these requirements in attainment areas. Thus, in order to allow time for these States
to revise their regulations to incorporate such requirements, this final action does not require regulation of SO2 orNOx as precursors to PM2. 5 under PSD until the SIP development period ends. In addition, we are allowing SIP-approved
PSD States to continue with the existing PM 10 surrogate policy to meet the PSD requirements forPM 2.5. However, for delegated PSD States, SO 2 and NOx are regulated as precursors from the effective date of this rule. However, these States or EPA have the option of excluding NOx as a precursor by demonstrating that NOx emissions are not a significant contributor to ambient PM2.5 concentrations in a particular

area.

For nonattainment areas, the transitional program pursuant to appendix S will apply on the effective date of this action. Under appendix S, SO 2 will be regulated as a precursor in all nonattainment areas for PM 2 . 5. - However, unlike in the proposal, NOx will notbe regulated as aprecursor for PM2.5 because we believe it is appropriate to give States the opportunity to determine whether NOx emissions are a significant contributor
to the ambient PM2. 5 problem, and to make the appropriate demonstration in their SIP. Finally, for States determining that VOC and/or ammonia are PM2. 5 precursors under their SIPs, we will approve their definition of "significant emissions rate" for each precursor based

on an appropriate demonstration.

K.Are thereany Tribalconcerns?

Some Tribal areas may be designated

as nonattainment, in part because of pollution that is transported from surrounding State lands. Tribal representatives have advocated for additional flexibility to address nonattainment problems caused by transported pollution, such as a pool of available NSR offset set-asides (which

we expect would come from State offset pools or banks), because they have limited ability to generate offsets on their own. Tribal representatives have raised these and other concerns in discussions on implementation of the 8- hour ozohe and PM 2.5 standards, and in
comments on the 8-hour ozone implementation rule. We requested comment on whether emissions offset set-asides, possibly generated by innovative measures to promote additional emissions reductions, are an appropriate method to help level theplaying field for the Tribes and support economic development in Tribal areas. We also requested comment on ways in which States may help -providethe Tribes access to offsets from non-Tribal

areas. We received no comments on these issues.

We recently proposed Tribal NSR rules. See 71 FR 48696, August 21, 2006. They include a NANSR rule, which refers to appendix S forits substantive requirements, and aminor NSR rule. Inrecognition ofthe concerns mentioned above, we have proposed and sought comments on options for obtaining offset reliefin that proposal. 

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We will address these issues inthe
context ofthat rule.

L. What arethe requirements forminor NSRforPM2.5 ?

Pursuant to section 110(a)(2)(C) ofthe Act, States must have a minor source permitting program. This applies to new arid modified stationary sources that are not considered major for a criteria pollutant or a precursor for a criteria pollutant. Prior to this action, States

were required to include the following pollutants in their minor NSR program:

* VOC, " SO 2, " NOx, * CO, " PM 1 0,and " Lead (Pb). Based on this action, States must now amend their minor source programs to include direct PM 2.5 emissions and
precursor emissions in the same manner
as included for purposes of PM2.5 major NSR.

M.Rural Transport Areas
In the proposal for the Clean Air Fine Particle ImplementAtion Rule and this NSR implementation rule for PM2. 5,we considered the option ofclassifying

some nonattainment areas as transport

areas that suffer from overwhelming transport, and of developing NA NSR rules specific to such areas. However, the final implementation rule does not include the rural transport classification. Conseqluently, no NA NSR rules have been developed or finalized in this rule.

VI. Statutory and Executive Order Reviews

A. Executive Order12866:Regulatory, Planning andReview
Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is a "significant regulatory action" because it is likely toraise novel legal or policy issues arising out oflegal mandates, the President's priorities, or theprinciples set forth in the Executive Order. Accordingly, EPA submitted this action to the Office ofManagement and Budget (OMB) for review under EO 12866 and any changes made in response to OMB recommendations have been documented in the docket for this action.

B. Paperwork ReductionAct
The information collection requirements in this rule have been' submitted for approval to the OMB under the Paperwork ReductionAct, 44 U.S.C. 3501 etseq. The information collection requirements are not enforceable until OMB approves them. The Information Collection Request (ICR) document prepared by EPA has been assigned OMB Control Number 2060-0003 (EPA ICR No. 1230.21).

To achieve the purposes of the major NSR program, certain records and reports are necessary for the Stateor local agency (orthe EPA Administrator innon-delegated States), for example,
to: (1) Confirm the compliance ofstatus ofstationary sources, identify any stationary sources -notsubject to the rules, and identify stationary sources subject to the rules; and (2) ensure that the stationary source control ' requirements are being achieved. The information would be used by EPA or State enforcement personnel to (1) identify stationary sources subject to the rules, (2) ensure that appropriate control technology is being properly applied, and (3) ensure that the emission control devices are being properly operated and maintained on acontinuous basis.

This final NSR rule does not create

new information collection requirements, but rather expands the coverage ofthe existing requirements of the major NSR program. Specifically, the rule changes finalized in This action afdd PM2.5 to the list ofair pollutants that must be addressed in the major NSR program, and the companion proposal adds certain elements that are necessary for a complete PM2.5 NSR program. This change is unlikely to increase significantly the number of NSR permits that must be issued, but may add to the analyses that sources and Federal, State, and local reviewing authorities must conduct as part of the construction permit application and review process.

We expect the rule changes finalized in this action to increase the.burden associated with major NSR permitting for tracking new emissions of PM2.5 against increments; collecting ambient air quality monitoring data for existing PM2.5 concentrations; reviewing the effects ofPM2.5 emissions on soils Wd vegetation, as well as on air quality related values in Class I areas; determining the appropriate best available controltechnology orlowest achievable emission rate; and/or obtaining offsets. At the same time, there would be areduction in burden directly associated with the revocation of the annual increment for PM 10,which is proposed inthe propbsed rule.

Over the 3-year period covered by the ICR, we estimate an average annual burden increase ofabout 39,000 hours (about 8 percent) and $4.3 million (about 10 percent) for all industry entities that would be affected by this final NSR rule. For the same reasons, we also expect the final rule to increase burden for the State and local authorities reviewing permit applications when fully implemented. In addition, there would be additional burden for State and local agencies to revise their SIPs to incorporate the proposed changes. We estimate the cgmbined increase in burden to average about 16,000 hours and $700,000 annually for all State and local reviewing autihsrities, which is less than 13 percent.

Burden means the total time, effort, or financial resources expended by persons to generate, maintain, retain, or disclose

orprovide information to or for a Federal agency. This includes the time needed to review instructions; develop, acquire, install, and utilize technology and systems for the purposes of collecting, validating, and verifying information, processinig and maintaining information, and disclosing and providing information; adjust the existing ways to comply with any previously applicable instructions and requirements; train personnel to be able to respond to a collection of information; search data sources; complete and review the collection of information; and transmit orotherwise disclose the information.

An agency may not conduct or sponsor, and a person is notrequired to respond to a collection of information unless it displays a currently valid OMB control number. The OMB control numbers for EPA's regulations in 40 CFR are listed in 40 CFR part 9. When this ICR is approved by OMB, the Agency will publish atechnical amendment to 40 CFR part 9 in the Federal Register to display the OMB control number for the approved information collection requirements contained in this final rule.

C.Regulatory Flexibility Act

. The Regulatory Flexibility Act (RFA) generally requires an agency to prepare
a regulatory flexibility analysis ofany rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or any other statute unless the Agency certifies that the rule will not have a significant economic impact on a substantial number ofsmall entities. Small entities include small businesses, small organizations, and small governmental jurisdictions.

For purposes of assessing the impacts ofthis proposed rule on small entities, "small entity" is defined as: (1) A small business as defined by the Small Business Administration's regulations at 13 CFR 121.201; (2) a small governmental jurisdiction that is a government ora city, county, town, I 

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school district or special district with a population ofless than 50,000; and (3)

a small organization that is any not-forprofit enterprise which is independently owned and operated and is not dominant in its field.

After considering the economic impacts ofthis final rule on small entities, I certify that this rule will not have a significant economic impact on

a substantial number ofsmall entities. The requirements ofthis final rule apply only to new major stationary sources or major modifications ofexisting major stationary sources. This final rule does not create anynew requirements under the major NSR program, but simply expands the program to cover an - additional pollutant, referred to as PM2. 5 . There is no reason to expect that the rule will significantly or uniquely affect small businesses, organizAtions, or governments (few, if any, ofwhich act

as reviewing authorities pursuant to this final rule).

D. UnfundedMandatesReformAct

Title II ofthe Unfunded Mandates Reform Act of 1995 (UMRA), Public Law 104-4, establishes requirements for Federal agencies to assess the effects of their regulatory actions on State, local, and tribal governments and the private
sector. Under section 202 ofthe UMRA,

.wegenerally must prepare a written statement, including a cost-benefit analysis, for proppsed and final rules with "Federal mandates" that may result in expenditures to State, local, and tribal governments, in aggregate, or to the private sector, of $100 million or
more in any 1year. Before promulgating

an EPA rule for which a written statement is needed, section 205 ofthe UMRA generally requires us to identify and consider a reasonable number of regulatory alternatives and adopt the least costly, most cost-effective, or least burdensome alternative that achieves the objectives ofthe rule. The provisions of section 205 do not apply when they are inconsistent with applicable law. Moreover, section 205 allows us to adopt an alternative other than the least-costly, most cost-effectivo,

or least-burdensome alternative ifthe Administrator publishes with the final rule an explanation ofwhy that alternative was not adopted. Before we establish any regulatory requirements that may significantly or uniquely affect 'small governments, including tribal governments, we must have developed under section 203 ofthe UMRA a small government agency plan. The plan must provide fornotifying potentially affected small governments, enabling officials ofaffected small governments to have meaningful and timely input in the development ofour regulatory proposals with significant Federal intergovernmental mandates; and informing, educating, and advising, small governments on compliance with the re ulatory requirements.

We ave determined that this rule does not contain a Federal mandate that may result in expenditures of$100 million or more for State, local, and tribal governments,-in the aggregate, or the private sector-in any 1year. The final rule does not add any new requirements to the NSR program; it simply expands the program to cover PM2. 5 in addition to the several other

- pollutants already defined as regulated NSR pollutants. (Technically, the rule also subjects the precursors to PM2.5to the NSR program. However, these precursors (SO 2,NOx" and VOC) are already subject to the existing NSR program.) As discussed previously in section VI.B on the Paperwork ReductionAct, the expansion of the NSR program to cover PM2. 5 will only marginally increase the expenditures of State, local, and tribal governments and the private sector on the program. Thus, this action is not subject to the requirements of sections 202 and 205 of the UMRA..

The EPA has determined that this rule contains noregulatory requirements that might significantly oruniquely affect small governments. As noted previously, thisrule does not create any
new requirements under the major NSR program, but simply expands the .program to cover an additional pollutant (PM 2.

5). There is no reason to expect that the rule will significantly or uniquely affect small governments, few if any of Which act as reviewing authorities.
E. Executive Order13132-Federalism

Executive Order 13132, entitled "Federalism" (64 FR 43255, August 10, 1999), requires us to develop an accountable process to ensure "meaningful and timely input by State and local officials in the development of regulatory policies that have federalism implications." "Policies that have federalism implications" is defined in the Executive Order to include regulations that have "substantial direct effects on the States, on the relationship between the national government-and the States, or on the distribution of powe and responsibilities among the various levels ofgovernment."

This final rule does not have federalism implications. It will not have substantial direct effects on the States,.

on the relationship between the national government and the States, or on the distribution ofpower and responsibilities among the various levels of government, as specified in Executive Order 13132. Pursuant to the terms ofExecutive Order 13132, it has been determined that this proposed rule does not have "federalism implications" because it does not meet the necessary criteria. Thus, the requirements of section 6 of the Executive Order do not apply to this proposed rule.

In the spirit ofExecutive Order 13132, however, and consistent with our policy to promote communications between us and State and local governments, we specifically solicited comment onthe proposed rule from State and local officials.

F.Executive Order13175-Consultation and CoordinationWith IndianTribal Governments

Executive Order 13175, entitled ','Consultation and Coordination with Indian Tribal Governments" (65 FR 67249, November 9, 2000), requires EPA to develop an accountable process to

ensure "meaningful and timely input by Tribal officials in the development of regulatory policies that have Tribal implications." This final rule does not have "Tribal implications" as defined in Executive Order 13175. This rule

concerns the NSR requirements for State and tribal implementation plans. The CAA provides for States to develop plans to regulate emissions of air pollutants within theirjurisdictions. The Tribal Air Rule (TAR) under the CAA gives Tribes the opportunity to develop and implement CAA programs such as programs to attain and maintain the PM 2.5 NAAQS, but it leaves to the discretion of the Tribe the decision of whether to develop theseprograms and which programs, or appropriate elements ofa program, they will adopt.

Although Executive Order 13175 does not apply to this rule, EPA did reach out to Tribal leaders and'environmental staffin developing thisrule. From 2001-2004, the EPA supported a National Designations,Workgroup to provide a forum for tribal professionals
to give input to the designations process. In 2006, EPA supported a national "Tribal Air call" which provides an open forum for all Tribes to voice concerns to EPA about the NAAQS implementation process, including the PM2. 5 NAAQS. In these meetings, EPA briefed call participants and Tribal environmental professionals gave input'as the rule was under development. Furthermore, in December 2005, EPA sent individualized letters to all federally recognized Tribes about the proposal to give Tribal leaders the opportunity for consultation.

This final rule does not have Tribal implications as defined by Executive 

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### .Order 13175. It does not have a substantial direct effect on one or more Indian Tribes, since no Tribe has implemented a CAA program to attain the PM2. 5 NAAQS'at this time. The EPA
notes that even ifa Tribe were implementing sich a plan at this time, while therule might have Tribal implications with respectto that Tribe, it would not impose substantial direct
costs upon.it, nor would itpreempt Tribal law.

Furthermore, thisrule does not affect the relationship or distribution ofpower and responsibilities between the Federal government andIndian Tribes. The CAA and the TAR establish the relationship ofthe Federal government and Tribes in developing plans to attain the NAAQS, and this rule does nothing
to modify that relationship. As this rule does not have Tribal implications, Executive Order 13175 does not apply.

G. Executive Order13045-Protection of ChildrenFromEnvironmental Health andSafety Risks

Executive Order 13045, entitled "Protection ofChildren from Environmental Health Risks and Safety Risks" (62 FR 19885, April 23, 1997), applies to any rule that: (1) Is determined to be "economically significant" as defined under Executive Order 12866; and (2) concerns an environmental health or safety risk that

we have reason td believe may have a disproportionate effect on children. If the regulatory action meets both criteria, the Agency must evaluate the environmental health or safety effects of the planned rule on children, and explain why the planned regulation is preferable to other potentially effective and reasonably feasible alternativesconsidered by the Agency.

This final rule is not subject to the Executive Order because it is not economically significant as defined in Executive Order 12866, and because the Agency does not have reason to believe the environmental health or safety risks addressed by this action present a disproportionate risk to children. This rule does not impose any new requirements under the NSR program. However, in expanding the major NSR program to address PM2. 5, we believe that this rule will serve to reduce environmental health risks to all citizens, including children, because

one ofthe basic requirements of the major NSR program is that new and modified major stationary sources must not cause or contribute to air quality in violation ofthe NAAQS. H. Executive Order13211-Actions That Significantly Affect EnergySupply, Distribution, or Use

This rule is not a "significant energy action" as defined inExecutive Order 13211, "Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution,-orUse" (66 FR 28355 (May 22, 2001)) because it is not likely to

. have a significant adverse effect on the supply, distribution, or use ofenergy. The final rule does not add any new requirements to the major NSR program; it simply expands the program to cover PM 2. 5 in addition to the several other pollutants already defined as regulated NSR pollutants. Although the major NSR program may apply to energy supply and distribution companies that build or significantly modify major

sources ofregulated NSRpollutants, we believe that any increase in expenditures for obtaining NSR permits that may resultfrom this rule will be marginal rather than significant.

L NationalTechnology Transferand AdvancementAct

As noted in the proposed rule, section 12(d) ofthe National Technology

- Transfer and Advancement Act of 1995 (NTTAA), Public Law No. 104-113, 12(d) (15 U.S.C. 272 note) directs us to

use voluntary consensus standards (VCS) in our regulatory and procurement activities unless to do so would be inconsistent with applicable law or otherwise impractical. The VCS

are technical standards (e.g., materials specifications, test methods, sampling procedures, and business practices) developed or adopted by one or more voluntary consensus bodies. The NTTAA directs us to provide Congress, through annual reports to OMB, with explanations when we do not use available and applicable VCS.

This final rule does not involve technical standards. Therefore, we did not consider the use ofany VCS.

J.Executive Order12898-Federal Actions toAddressEnvironmental Justicein MinorityPopulations and Low-Income Populations

ExecutiveOrder 12898 (59 FR 7629 (Feb. 16, 1994)) establishes Federal executive policy on environmental justice. Its main provision directs Federal agencies, to the greatest extent practicable and permitted by law, to make environmental justice part oftheir mission by identifying and addressing,

as appropriate, disproportionately high and adverse human health -or environmental effects ofits programs, policies, and activities on minorities and low-income populations in the United States.

The EPA has determined that this final rule will nothave disproportionately high and adverse human health or environmental effects

on minority or low-income populations because it will have the effect of improving air quality. While it does not impose any new requirements under the major NSR program, we believe that this rule, in expanding the NSR program to address PM2. 5 , will serve to reduce adverse human health and environmental effects for all citizens, including minorities and low-income populations.

K. Congressional ReviewAct The Congressional Review Act, 5 U.S.C. 801 etseq., as added by the Small Business Regulatory Enforcement Fairness Act of 1996, generally provides thatbefore arule may take effect, the agency promulgating the rule must submit a rule report, which includes a copy ofthe rule, to each House ofthe Congress and to the Comptroller General ofthe United States. The EPA will submit a report containing thisrule and other required information to the U.S. Senate, the U.S. House of Representatives, and the Comptroller General of the United States -priorto publication ofthe rule inthe Federal Register. A major rule cannot take effect until 60 days after it is published in the Federal Register. This action is not a "major rule" as defined by 5 U.S.C. 804(2). The rules affected bythis action will be effective July 15, 2008.

L. Petitions forJudicial Review
Under section 307(b)(1) ofthe Act, petitions forjudicial review ofthis action must be filed in the United States Court of Appeals for the District of Columbia Circuit byJuly 15, 2008. Filing a petition for reconsideration by the Administrator of this final rule does not affect the finality ofthis rule forthe purposes ofjudicial review nor does it extend the time within which a petition forjudicial review maybe filed, and shall not postpone the effectiveness of such rule or action. This action may not be challenged later in proceedings to enforce its requirements. See Act section 307(b)(2).

M.DeterminationUnderSection 307(d)

.The PSD portions of this rulemaking, which implements part C oftitle I ofthe Act, are subject to the proceduralrequirements in section 307(d) of the Act. See section 307(d)(1)(J). In addition, pursuant to section 307(d)(1)(V) ofthe Act, the Administrator determines that the NA 

### 28346Federal Register/Vol. 73, No.'96/Friday, May:'16, 2008/Rules and Regulations

NSR portions ofthis'action should also be subject to the provisions ofsection 307(d) to ensure consistency. All of the procedural requirements ofsection 307(d), e.g., docketing, hearing, and comment periods, have been complied with during the course ofthis rulemaking.

VII. Statutory Authority

The statutory authority for this action is provided by sections 101, 110, 165, 169, 172, 173, 301, and 302 ofthe Act

as amended (42 U.S.C. 7401, 7410, 7475, 7479, 7502, 7503, 7601, and 7602). This rulemaking is also subject to section 307(d) ofthe Act (42 U.S.C. 7407(d)).
List of Subjects

40 CFRPart51

Environmental protection, Administrative practices and procedures, Air pollution control, Intergovernmental relations.

40 CFRPart52

Environmental protection, Administrative practices and procedures, Air pollution control, Intergovernmental relations.

Dated: May 8, 2008. Stephen L. Johnson, Administrator.

mForthe reasons stated in the preamble, title 40, chapter Iof the Code ofFederal Regulations is amended as follows.

PART 51-fAMENDED]

m 1. The authority citation for part 51 continues to read as follows:

Authority: 23 U.S.C. 101; 42 U.S.C. 7401- 7671q. 

### Subpart I--[Amended]

* 2. Section 51.165 isamended as follows: " a.By revising paragraph (a)(1)(x)(A); " b. By removing the word "or" at the end of paragraph (a)(1)(xxxvii)(B);


### mc.By revising paragraph (a)(1)(xxxvii)(C); * d.By adding paragraph (a)(1)(xxxvii)(D);


### me.By redesignating paragraphs (a)(9)(i) through (iii) as paragraphs (a)(9)(ii) through (iv), respectively, and adding

- new paragraph (a)(9)(i);


### mf.By removing from newly redesignated paragraph (a)(9)(iii) the reference to "paragraph (a)(9)(i)" and adding in its place "paragraph (a)(9)(ii)"; and


### mg.By adding paragraph (a)(11).
§51.165 Permit requirements. 

### (a)* * * (1)* * *

. .. (x)(A) Significantmeans, inreference to a net emissions increase orthe potential ofa-source to emit any ofthe following pollutants, a rate ofemissions that would equal orexceed any ofthe following rates:
Pollutant Emission Rate
Carbon monoxide: 100 tons per year

(tpy) Nitrogen oxides: 40 tpy Sulfur dioxide: 40 tpy Ozone: 40 tpy ofvolatile organic

compounds or nitrogen oxides Lead: 0.6 tpy PMIo: 15 tpy PM2. 5: 10 tpy of direct PM2. 5 emissions; 40 tpy ofsulfur dioxide emissions; 40 tpy ofnitrogen oxide emissions unless demonstrated not to be a PM2. 5 precursor under paragraph (a)(1)(xxxvii) ofthis section

* * * * *

(xxxvii)* * * (C) Any pollutant that is identified under this paragraph (a)(1)(xxxvii)(C) as
a constituent or precursor ofa general pollutant listed under paragraph (a)(1)(xxxvii)(A) or (B) ofthis section, provided that such constituent or precursor pollutant may only be regulated under NSR as part of regulation ofthe general pollutant. Precursors identified by the Administrator for purposes ofNSR are the following: (1) Volatile organic compounds and nitrogen oxides are precursors.to ozone in all ozone nonattainment areas. (2)Sulfur dioxide is aprecursor to PM2. 5 in allPM2. 5 nonattainment areas. (3)Nitrogen oxides are presumed to be precursors to PM 2. 5 in all PM2. 5 nonattainment areas, unless the State demonstrktes to the Administrator's satisfaction or EPA demonstrates that emissions ofnitrogen oxides from

sources in a specific area are not a significant contributor to that area's ambient PM 2 .5 concentrations.

(4) Volatile organic compounds and ammonia are presumed not tobe precursors to PM2. 5 in any PM2. 5 nonattainment area, unless the State demonstrates to the Administrator's satisfaction orEPA demonstrates that emissions ofvolatile organic compounds or ammonia from sources in

a specific area are a significant contributor to that area's ambient PM2.5 concentrations; or

(D) PM2. 5 emissions and PM10 emissions shall include gaseous emissions from asource or activity which condense to form particulate

- matter at ambient temperatures. On or

after January 1, 2011 (or any earlier date established in the upcoming rulemaking codifying test methods), such condensable particulate matter shall be accounted for in applicability determinations and in establishing emissions limitations for PM2. 5 and PM 1 0 in nonattainment major NSR permits. Compliance with emissions limitations forPM2. 5 and PM 0 issued prior to this date shall not be based on condensable particulate matter unless required by the terms and conditions of the permit or the applicable implementation plan. Applicability determinations made prior to this date without accounting for condensable particulate matter shall notbe considered in violation ofthis section unless the applicable implementation plan required condensable particulate matter to be included.

* * * * *

(9)(i) The plan shall require that in meeting the emissions offset requirements ofparagraph (a)(3) ofthis section, the ratio oftotal actual emissions reductions to the emissions increase shall be at least 1:1 unless an alternative ratio is provided for the applicable nonattainment area in paragraphs (a)(9)(ii) through (a)(9)(iv) of this section.

(11) The plan shall require that in meeting the emissions offset

- requirements ofparagraph (a)(3) ofthis section, the emissions offsets obtained shall be for the same regulated NSR pollutant unless interprecursor offsetting is permitted for a particular pollutant as specified in this paragraph., The plan may allow the offset requirements in paragraph (a)(3) ofthis section for direct PM2. 5 emissions or emissions ofprecursors ofPM2.sto be satisfied by offsetting reductions in direct PM2.5 emissions or emissions of any PM2. 5 precursor identified under paragraph (a)(1)(xxxvii)(C) of-this section if such offsets comply with the interprecursor trading hierarchy and ratio established in the approved plan fora particular nonattainment area.



### m3. Section 51.166 is amended as follows:

ma. By revisingparagraphs (b)(23)(i) and (b)(49)(i);

m

b. By removing theword "or" at the end ofparagraph (b)(49)(iii);

mc. By adding and reserving paragraph (b)(49)(v);



### md. By adding paragraph (b)(49)(vi); and



### me. By revisingparagraphs (i)(5)(ii) and (i)(5)(iii). 

### 28347Federal Register/ Vol. 73, No. 96/ Friday, May 16, 2008 / Rules and Reg-Jations

§51.166 Pevention of significant deterioration of air quality.

* * * * *

(23)(i) Significantmeans, in reference
to a net emissions increase or the potential ofa source to emit any ofthe following pollutants, a rate of emissions that would equal or exceed any ofthe following rates:
Pollutant and Emissions Rate

Carbon monoxide: 100 tons per year

(tpy) Nitrogen oxides: 40 tpy Sulfur dioxide: 40 tpy Particulate matter: 25 tpy of particulate

matter emissions. 15 tpy ofPM10 emissions PM2.5: 10 tpy of direct PM2. 5 emissions; 40 tpy ofsulfur dioxide emissions; 40 tpy of nitrogen oxide emissions unless demonstrated not to be a PM 2 . 5 precursor under paragraph (b)(49) of this section Ozone: 40 tpy ofvolatile organic

compounds or nitrogen oxides Lead: 0.6 tpy Fluorides: 3 tpy Sulfuric acid mist: 7 tpy Hydrogen sulfide (H2S): 10 tpy Total reduced sulfur (includirig H2S): 10

tpy Reduced sulfur compounds (including

H2S): 10 tpy Municipal waste combustor organics (measured as total tetra-through octachlorinated dibenzo-p-dioxins and dibenzofurans): 3.2 x 10 - - 6

megagrams per year (3.5 x 10-6 tons per year) Municipal waste combustormetals

(measured as particulate matter): 14 megagrams per year (15 tons per year) Municipal waste combustor acid gases

(measured as sulfur dioxide and hydrogen chloride): 36 megagrams per year (40 tons per year) Municipal solid waste landfill

emissions (measured as nonmethane organic compounds): 45 megagrams per year (50 tons per year)

* *

- * * *

(49) * * * (i)

Any pollutant for which a national ambient air quality standard has been promulgated and any pollutant identified under this paragraph (b)(49)(i)

as a constituent or precursor to such pollutant. Precursors identified by the Administrator for purposes ofNSR are the following:

(a) Volatile organic compounds and nitrogen oxides are precursors to ozone in all attainment and unclassifiable

areas.

(b) Sulfur dioxide is a precursor to PM2. 5 in all attainment and unclassifiable areas. (c) Nitrogen oxjdes are presumed to be precursors to PM2. 5 in all attainment and unclassifiable areas, unless the State demonstrates to the Administrator's satisfaction or EPA demonstrates that emissions of nitrogen oxides from sources in a specific area
are not a significant contributor to that area's 

### unbient PM 2. 5 concentrations. (d) Volatile organic compounds are presumed not to be precursors to PM2.5 in any attainment orunclassifiable area, unless the State demonstrates to the Administrator's satisfaction or EPA demonstrates that emissions ofvolatile organic compounds from sources in a specific area are a significant contributor to that area's ambient PM2.5 concentrations.

* * * * *

(v) [Reserved.] (vi) Particulate matter (PM) emissions, PM2.5 emissions, and PM 1

### oemissions shall include gaseous emissions from a

source or activity which condense to form particulate matter at ambient temperatures. On or after January 1, 2011 (or any earlier date established in the upcoming rulemaking codifying test methods), such condensable particulate
matter shall be accounted for in applicability determinations and in establishing emissions limitations for PM, PM2. 5 and PM 10 in PSD permits. Compliance with emissions limitations for PM, PM2. 5 and PMoissued prior to this date shall not be based on condensable particular matter unless required by the terms and conditions of the permit or the applicable implementation plan. Applicability determinations made prior to this date without accounting for condensable particular matter shall notbe considered in violation of this section unless the applicable implementation plan required condensable particular matter tobe included.

* * * * *

(i) * * * (5) * * * (ii)The concentrations ofthe pollutant in the area that the source or modification would affect are less than the concentrations listed inparagraph (i)(5)(i) .of this section; or (iii)The pollutant is not listed in paragraph (i)(5)(i) ofthis section.

* -* * * *
E 4:Appendix S to Part 51 is amended

as follows: * a. By revisingparagraphs II.A.10(i) and fl.A.31; * b.By revising paragraph IV.A, Condition 3;


### mc. By redesignating paragraphs IV.G.1 through IV.G.3 as paragraphs IV.G.2 through IV.G.4, respectively, and adding

new paragraph IV.G.1;

md. By removing from newly redesignated paragraph IV.G.3 the reference to "paragrAph IV.G.1" and adding in its place "paragraph IV.G.2"; and


### me. By adding paragraph IV.G.5. Appendix S -to Part 51-Emission Offset Interpretative Ruling

* * * * *

II.

* * * A.* * 10. (i) Significantmeans, in reference to a net emissions increase orthe potential ofa
source to emit any ofthe following pollutants, a rate ofemissions that would equal or exceed any ofthe following rates: Pollutant and Emissions Rate Carbon monoxide: 100 tons per year (tpy) Nitrogen oxides: 40 tpy Sulfur dioxide: 40 tpy Ozone: 40 tpy ofvolatile organic compounds

ornitrogen oxides Lead: 0.6 tpy Particulate matter: 25 tpy ofparticulate

matter emissions PM1o: 15 tpy

PM 2 .5: 10 tpy of direct PM2. 5 emissions; 40 tpy ofsulfur dioxide emissions

* * * * *

31. RegulatedNSRpollutant,forpurposes of thisRuling, means the following:

(i)Nitrogen oxides or any volatile organic compounds;

(ii)Any pollutant for which a national ambient air quality standard has been promulgated;

(iii)Any pollutant that is identified under this paragraph II.A.31(iii) as a constituent or precursor ofa general pollutant listed under paragraph ll.A.31(i) or (ii)ofthis Ruling, provided that such constituent or precursor pollutant may only be regulated underNSR

as part ofregulation of the general pollutant. Precursors identified by the Administrator for purposes ofNSR are the following:

(a) Volatile organic compounds and nitrogen oxides are precursors to ozone in all

ozone nonattainment areas.

(b) Sulfur dioxide is a precursor to PM2

_ 5 in all PM 2. 5 nonattainment areas; or (iv) Particulate matter (PM)emissions, PM2,5 emissions and PMie emissions shall include gaseous emissions from a source or activity which condense to form particulate matter at ambient temperatures. On or after January 1, 2011 (or any earlier date established in the upcoming rulemaking codifying test methods), such condensable particulate matter shall be accounted for in applicability determinations and in establishing emissions limitations for PM,
PM2 . 5 andPM10 in permits issued under this ruling. Compliance with emissions limitations for PM, PM2. 5and PMo issued priorto this date shall notbe based on condensable particulate matter unless required by the terms and conditions ofthe permit orthe applicable implementation plan. Applicability determinations made priorto this date without accounting for condensable particulate matter shall not be 28348

### Federal Register/Vol. 73, No. 96/ Friday, May 16, 2008 /Rules and Regulations

considered in violation of this section unless the applicable implementation plan required condensable particulate matter to be included.

* * * * *t

IV. * * * A. * * * Condition3. Emission reductions (offsets) from existing sources 5 in the.area of the proposed source (whether ornot under the

same ownership) are required such that there willbe reasonable progress toward attainment ofthe applicable NAAQS. Except

as provided in paragraph IV.G.5 ofthis Ruling (addressing PM2.5and its precursors), only intrapollutant emissibn offsets will be acceptable (e.g., hydrocarbon increases may notbe offset against SO 2reductions).

5Subject to the provisions of paragraph 

### IV.C ofthis Ruling.

6The discussion in this paragraph is a proposal, but represents EPA's interim policy untilfinal rulemaking is completed.

. * * * *

G. Offsetratios. 1. In meeting the emissions offset requirements of paragraph IV.A, Condition 3 ofthis Ruling, the ratio of total actual emissions reductions to the emissions increase shall be at least 1:1 unless an alternative ratio is provided for the applicable nonattainment aredin paragraphs IV.G.2 through IV.G.4.

* * * * *

5. Interpollutant offsetting.In meeting the emissions offset requirements ofparagraph IV.A, Condition 3 ofthis Ruling, the emissions offsets obtained shallbe for the

same regulated NSR pollutant unless interpollutant offsetting is permitted for a particular pollutant as specified inthis paragraph IV.G.5. The offsetrequirements of paragraph IV.A, Condition 3of thisRuling for direct PM 2.5emissions oremissions of precursors ofPM2. 5may be satisfied by offsetting reductions of direct.PM2.5 emissions or emissions of any PM2 . 5 precursor identified under paragraph II.A.31 (iii)ofthis Ruling ifsuch offsets comply with

an interprecursor trading hierarchy andratio approved bythe Administrator.

* * *

. * *

PART 52--[AMENDED]

u 5. The authority citation for part 52 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq. Subpart A-f[Amended]

* 6. Section 52.21 is amended as follows:


### ma. By revisingparagraphs (b)(23)(i) and (b)(50)(i);

mb. Byremoving the word "or" at the end ofparagraph (b)(50)(iii);

a c. By adding and reserving paragraph (b)(50)(v];

n d. By adding paragraphs (b)(50)(vi) and (i)(1)(xi);


### me. By revisingparagraph (i)(5)(ii); and * f. By adding paragraph (i)(5)(iii). §52.21 Prevention of significant deterioration of airquality.

* * * * *



### (b)* (23)(i) Significant means, in reference to a net emissions increase or the potential ofa source to emit any ofthe following pollutants, a rate of emissions that would equal or exceed any ofthe following rates:
Pollutant and Emissions Rate
Carbon monoxide: 100 tons per year

(tpy) Nitrogen oxides: 40 tpy Sulfur dioxide: 40 tpy Particulate matter: 25 tpy ofparticulate

matter emissions PM1o: 15 tpy PM2. 5: 10 tpy ofdirect PM2. 5 emissions; 40 tpy ofsulfur dioxide emissions; 40 tpy of nitrogen oxide emissions unless demonstrated not to be a PM2. 5 precursor underparagraph (b)(50) of this section Ozone: 40 tpy ofvolatile organic

compounds or nitrogen oxides Lead: 0.6 tpy Fluorides: 3 tpy Sulfuric acid mist: 7tpy Hydrogen sulfide (H2S): 10 tpy Total reduced sulfur (including H 2 S): 10

tpy Reduced sulfur compounds (including

H 2S): 10 tpy Municipal waste combustor organics

(measured as total tetra-through octachlorinated dibenzo-p-dioxins and dibenzofurans): 3.2 x 10 6 megagrams per year (3.5 x 10 6
tons per year) Municipal waste combustor metals

.(measured as particulate matter): 14 megagrams per year (15 tons per year) Municipal waste combustor acid gases

(measured as §ulfur dioxide and hydrogen chloride): 36 megagrams per year (40 tons per year) Municipal solid waste landfills

emissions (measured as nonmethane organic compounds): 45 megagrams per year (50 tons per year)

* * * * *

(50)* * * (i) Any pollutant for which a national ambient air quality standard has been promulgated and any pollutant identified under this paragraph (b)(50)(i)

as a constituent or precursor for such pollutant. Precursors identified by the Administrator for purposes ofNSR are the following:

(a) Volatile 6rganic compounds and nitrogen oxides are precursors to ozone in all attainment and unclassifiable

areas.

(b) Sulfur dioxide is aprecursor to PM 2.5 in all attainment and unclassifiable areas. (c)Nitrogen oxides are presumed to be precursors to PM2.5 in all attainment and unclassifiable areas, unless the State demonstrates to the Administrator's satisfaction orEPA demonstrates that emissions of nitrogen oxides from sources in a specific area
are not a significant contributor to that area's ambient PM 2 .5 concentrations.

(d) Volatile organic compounds are presumed not to be precursors to PM2.5 in any attainment or unclassifiable area, unless the State demonstrates to the Administrator's satisfaction orEPA demonstrates that emissions of volatile organic compounds from sources in a specific area are a significant contributor to that area's ambient PM2.5 concentrations.

* * * * *

(v) [Reserved.] (vi) Particulate matter (PM) emissions, PM2. 5 emissions and PMI 0 emissions shall include gaseous emissions from a
source or activity which condense to form particulate matter at ambient temperatures. On or after January 1, 2011 (orany earlier date established in the upcoming rulemaking codifying test methods), such condensable particulate matter shall be accounted forin applicability determinations and in establishing emissions limitations for PM, PM2.5and PM 10 in PSD permits. Compliance with emissions limitations for PM, PM2.5 and PMI 0 issued priorto this date shall not be based on condensable particular matter unless required by the terms and conditions of the permit or the applicable

- implementation plan. Applicability determinations made prior to this date without accounting for condensable particular matter shall notbe considered in violation ofthis section unless the applicable implementation plan required condensable particular matter to be included.

* * * * *



### (i] * * * (1)*

... (xi) The source or modification was subject to 40 CFR 52.21, with respect to PM2.5, as in effect before July 15, 2008, and the owner or operator submitted an application for a permit under this section before that date consistent with EPA recommendations'to use PM 0 as a surrogate for PM2. 5, and the Administrator subsequently determines that the application as submitted was complete with respect to the PM2.5 requirements then in effect, as interpreted in the EPA memorandum entitled "Interim Implementation of New Source Review Requirements for PM 2.5" (October 23, 1997). Instead, the requirements ofparagraphs (j)through 

### 28349

### Federal Register/Vol. 73, No. 96/ Friday, May 16, -2008/Rules and Regulations

(r) ofthis section, as interpreted in the aforementioned memorandum, that

were in effect before July 15, 2008 shall -applyto such source or modification.

* * * * *

(5) * * * (ii) The concentrations ofthe pollutant in the area that the source or modification would affect are less than the concentrations listed in paragraph (i)(5)(i) ofthis section; or

(iii) The pollutant is not listed in paragraph (i)(5)(i) ofthis section.

* * * * * [FRDoc. E8-10768 Filed 5-15-08; 8:45 am]

BILLING CODE 6560-50-P

DEPARTMENT OF HOMELAND SECURITY

Federal Emergency Management Agency

44 CFR Part 67

Final Flood Elevation Determinations
AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final rule.

SUMMARY: Base (1% annual chance) Flood Elevations (BFEs) and modified BFEs are made final for the communities listed below. The BFEs and modified BFEs are the basis for the floodplain management measures that each community is required either to adopt orto show evidence ofbeing already in effect in order to qualify or remain qualified for participation in the National Flood Insurance Program (NFIP). DATES: The date ofissuance ofthe Flood Insurance Rate Map (FIRM) showing BFEs and modified BFEs for each community. This date maybe obtained by contacting the office where the maps
are available for inspection as indicated

on the table below. ADDRESSES: The final BFEs for each community are available forinspection at the office of the ChiefExecutive Officer ofeach community. The respective addresses are listed in the table below.

FOR FURTHER INFORMATION CONTACT: William R. Blanton, Jr., Engineering Management Branch, Mitigation Directorate, Federal Emergency Management Agency, 500 C Street, SW., Washington, DC 20472, (202) 646-3151.

SUPPLEMENTARY INFORMATION: The Federal Emergency Management Agency (FEMA) makes the final determinations listed below for the modified BFEs for each.cornmunity listed. These modified elevations have been published in newspapers oflocal circulation and ninety (90) days have elapsed since that publication. The Assistant Administrator ofthe Mitigation Directorate has resolved any appeals resulting from this notification.

This final rule is issued in accordance with section 110 ofthe Flood Disaster Protection Act of 1973, 42 U.S.C. 4104, and 44 CFR part 67. FEMA has developed criteria for floodplain management in floodprone areas in accordance with 44 CFR part 60.

Interested lessees and owners ofreal property are encouraged to review the proofFlood Insurance Study and FIRM available at the address cited below for each community. The BFEs and modified BFEs are made final'in the communities listed below. Elevations at selected locations in each community

are shown. National EnvironmentalPolicy Act. This final rule is categorically excluded from the requirements of44 CFR part 10, Environmental Consideration. An environmental impact assessment has not beet prepared.

RegulatoryFlexibility Act. As flood elevation determinations are not within the scope ofthe Regulatory Flexibility Act, 5 U.S.C. 601-612, a regulatory flexibility analysis is not required.

RegulatoryClassification.This final rule is not a significant regulatory action under the criteria of section 3(f) of Executive Order 12866 ofSeptember 30, 1993, Regulatory Planning and Review, 58 FR 51735.

Executive Order13132,Federalism. This final rule involves no policies that have federalism implications under Executive Order 13132.

Executive Order12988, CivilJustice Reform. This final rule meets the applicable standards ofExecutive Order 12988.

List ofSubjects in 44 CFR Part 67

Administrative practice and procedure, Flood insurance, Reporting and recordkeeping requirements.

mAccordingly, 44 CFRpart 67 is amended as follows:

PART 67-[AMENDED]

m1. The authority citation for part 67 -continues to read as follows: Authority: 42 U.S.C. 4001 etseq.; Reorganization Plan No. 3 of 1978, 3 CFR, 1978 Comp., p. 329; E.O. 12127, 44 FR 19367, 3 CFR, 1979 Comp., p. 376. §67.11 [Amended]

m2. The tables published under the authority of § 67.11 are amended as follows:

* Elevation in feet (NGVD)
+ Elevation in feet Communities Flooding source(s) Location of referenced elevation (NAVD) affected # Depth in feet above ground Modified
Randolph County, Illinois, and Incorporated Areas Docket No.: FEMA-B-7740

•Kaskaskia River

.....................

Mississippi River

.................... At confluence with Mississippi River

....................................

Randolph/Monroe County boundary (approximately 700

feet upstream Anna Lane extended). Jackson/Randolph County boundary (approximately Cora

Road extended). +392

+392

+382 Village of Evansville, Unincorporated Areas of Randolph County.

City of Chester, Unincorporated Areas of Randolph County, Village of Kaskaskia, Village of Prairie Du Rocher, Village of Rockwood. 

### 28350