Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 28321 

No comments objecting to the proposal 

were received. Class E airspace areas 

extending from 700 feet or more above 

the surface of the earth are published in 

paragraphs 6005 of FAA 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 

of Federal 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 of technical regulations for which 

frequent and routine amendments are 

necessary to keep 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 of a 

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 of the 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 of the FAA administrator. 

Subtitle VII, Aviation Programs, 

describes in more detail the scope of the 

agency’s authority. 

This rulemaking is promulgated 

under the authority described in 

Subtitle VII, Part A, Subpart I, Section 

40103. Under that section, the FAA is 

charged with prescribing regulations to 

assign the use of airspace necessary to 

ensure the safety of aircraft and the 

efficient use of airspace. This regulation 

is within the scope of that 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 of the Amendment 

■ In consideration of the 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 

■ 1. The authority citation for part 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] 

■ 2. The incorporation by reference in 

14 CFR 71.1 of Federal 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 Class E Airspace Areas 

Extending Upward from 700 feet or More 

Above the Surface of the Earth. 

* * * * * 

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 of the Earth within an 

8.3-mile radius of Green County Airport. 

* * * * * 

Issued in College Park, Georgia, on April 

21, 2008. 

Lynda G. Otting, 

Acting Manager, System Support Group, 

Eastern Service Center, Air Traffic 

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 of enforcement of 

regulation. 

SUMMARY: The Coast Guard will enforce 

the Portland Rose Festival Security 

Zone on the Willamette River from 1 

a.m. on June 4, 2008 until 10 a.m. June 

10, 2008. This action is necessary for the 

security of public vessels on a portion 

of the Willamette River during the fleet 

week of the Rose Festival. This security 

zone provides for the regulation of 

vessel traffic in the vicinity of the 

moored public vessels. During the 

enforcement period, entry into this zone 

is prohibited unless authorized by the 

Captain of the Port or his 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 of 33 CFR 

165.33 a vessel may not enter the 

regulated area, unless it receives 

permission from the Captain of the Port 

or his designee. The Coast Guard may be 

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 will provide 

the maritime community with extensive 

advance notification of this enforcement 

period via the Local Notice to Mariners 

and marine information broadcasts. 

Dated: May 6, 2008. 

F.G. Myer, 

Captain, U.S. Coast Guard, Captain of the 

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 

(PM2.5) 

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, 


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

generally referred to as ‘‘PM2.5’’). The 

NSR program was created by the Clean 

Air Act (Act or CAA) to ensure that 

stationary sources of air pollution are 

constructed or modified in a 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 all the SIPs related provisions. 

In this rulemaking, EPA is finalizing the 

NSR provisions of the November 1, 2005 

proposed rule including the major 

source threshold, significant emissions 

rate, and offset ratios for PM2.5, 

interpollutant trading for offsets and 

applicability of NSR to PM2.5 precursors. 

DATES: This final rule is effective on July 

15, 2008. 

ADDRESSES: The EPA has established a 

docket for this action under Docket ID 

No. EPA–HQ–OAR–2003–0062. All 

documents in the docket are listed on 

the www.regulations.gov Web site. 

Although listed in the index, some 

information may not be 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 and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available either electronically through 

www.regulations.gov or 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 legal holidays. The telephone 

number for the Public Reading Room is 

(202) 566–1744, and the telephone 

number for the Air Docket is (202) 566–

1742. 

FOR FURTHER INFORMATION CONTACT: Mr. 

Raghavendra (Raj) Rao, Air Quality 

Policy Division, Office of Air Quality 

Planning and Standards (C504–03), U.S. 

Environmental Protection Agency, 

Research Triangle Park, North Carolina 

27711, telephone number: (919) 541–

5344, facsimile number: (919) 541–5509, 

e-mail address: rao.raj@epa.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 this action apply to 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 .................................................................. 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 

a North 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 can I get a copy of this 

document and other related 

information? 

In addition to being available in the 

docket, an electronic copy of this final 

rule will also be available on the World 

Wide Web. Following signature by the 

EPA Administrator, a copy of this final 

rule will be posted in the regulations 

and standards section of our NSR home 

page located at http://www.epa.gov/nsr. 

C. How is this preamble organized? 

The information presented in this 

preamble is organized as follows: 

I. General Information 

A. Does this action apply to me? 

B. Where can I get a copy of this 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 PM2.5

C. Implementation of NSR for PM2.5

IV. Overview of This Final Action 

V. Rationale for Final Actions 

A. Applicability of NSR to Precursors of 

PM2.5 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 SO2

4. Final Action on NOX

5. Final Action on VOC 

6. Final Action on Ammonia 

B. Major Stationary Source Threshold for 

PM2.5

C. Significant Emissions Rate for Direct 

Emissions of PM2.5

D. Significant Emissions Rates for PM2.5

Precursors 

E. Condensable PM Emissions 

F. Prevention of Significant Deterioration 

(PSD) Program Requirements 

1. How must BACT be implemented for 

PM2.5? 

2. How does EPA plan to address PM2.5

Increments, Significant Impact Levels 

(SILs), and Significant Monitoring 

Concentrations (SMCs)? 

3. What is the ambient air quality analysis 

requirement for PM2.5? 

4. How must the PSD preconstruction 

monitoring requirement be implemented 

for PM2.5? 

G. Nonattainment New Source Review (NA 

NSR) Requirements 

1. What is the required offset ratio for 

direct PM2.5 emissions? 

2. Which precursors are subject to the 

offset requirement? 

3. What is the required offset ratio for PM2.5

precursors? 

4. Is interpollutant trading allowable to 

comply with offset requirements? 

H. How will the transition to the PM2.5 PSD 

requirements occur? 

1. Background 

2. Transition for ‘‘Delegated States’’

3. Transition for ‘‘SIP-Approved States’’

I. How will the transition to the PM2.5 NA 

NSR requirements occur? 

1. Background 

2. Transition 


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

1 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. 

2The Act uses the terms ‘‘major emitting facility’’

to refer to sources subject to the PSD program, and 

‘‘major stationary source’’ to refer to sources subject 

to NA NSR. See CAA sections 165, 169, 172(c)(5), 

and 302(j). For ease of reference, we use the term 

‘‘major source’’ to refer to both terms. 

3The term ‘‘criteria pollutant’’ means a pollutant 

for which we have set a NAAQS. 

4 In addition, the PSD program applies to most 

noncriteria regulated pollutants. 

3. Implementation of NSR Under the 

‘‘Emissions Offset Interpretative Ruling’’

(40 CFR part 51, appendix S) with 

Revisions 

J. Does major NSR apply to PM2.5

precursors during the SIP development 

period? 

K. Are there any Tribal concerns? 

L. What are the requirements for minor 

NSR for PM2.5? 

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 of this rulemaking 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 1 promulgated on 

April 25, 2007 at 72 FR 20586. This 

final action on the bulk of the major 

NSR program for PM2.5 along with our 

proposed rule on increments, SILs, and 

SMC, when final, will represent the 

final elements necessary to implement a 

PM2.5 PSD program. When both rules are 

promulgated and in effect, the PM2.5

PSD program will no longer use a PM10

program as a surrogate, as has been the 

practice under our existing guidance. 

III. Background 

A. New Source Review (NSR) Program 

The existing regulations require both 

major and minor NSR programs to 

address any pollutant for which there is 

a National Ambient Air Quality 

Standard (NAAQS) and precursors to 

the formation of such pollutant when 

identified for regulation 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 PM2.5 NAAQS. This 

preamble also explains what interim 

provisions would apply with respect to 

PM2.5 during 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 of three 

different programs: 

• 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 a major 

modification.3 4 The 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 or undergoes 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 of the area 

in which a source is located. 

The national regulations that apply to 

each of these programs are located in 

the Code of Federal 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 of Best Available 

Control Technology (BACT); 

• Air quality monitoring and 

modeling analyses to ensure that a 

project’s emissions will not cause or 

contribute to a violation of any NAAQS 

or maximum allowable pollutant 

increase (PSD increment); 

• Notification of Federal Land 

Manager of nearby Class I areas; and 

• Public comment on the permit. 

Nonattainment NSR requirements 

include but are not limited to: 

• Installation of Lowest Achievable 

Emission Rate (LAER) control 

technology; 

• Offsetting new emissions with 

creditable emissions reductions; 

• 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, or modification; and 

• Public comment on the permit. 

Minor NSR programs must meet the 

statutory requirements in section 

110(a)(2)(C) of the Act, which requires 

‘‘* * * regulation of the modification 

and construction of any stationary 

source * * * as necessary to assure that 

national ambient air quality standards 

are achieved.’’

B. Fine Particulate Matter and the 

NAAQS for PM2.5

Fine particles in the atmosphere are 

made up of a complex mixture of 

components. Common constituents 

include sulfate (SO4); nitrate (NO3); 

ammonium; elemental carbon; a great 

variety of organic compounds; and 

inorganic material (including metals, 

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 of 2.5 

micrometers or less (a micrometer is 


sroberts on PROD1PC70 with RULES
28324 Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 

5Available in the docket for this rulemaking, ID 

No. EPA–HQ–OAR–2003–0062, and at http:// 

www.epa.gov/region07/programs/artd/air/nsr/ 

nsrmemos/pm25.pdf. 

6Available in the docket for this rulemaking, ID. 

No. EPA–HQ–OAR–2003–0062, and at http:// 

www.epa.gov/nsr/documents/nsrmemo.pdf. 

one-millionth of a meter, and 2.5 

micrometers is less than one-seventh the 

average width of a human 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 in the atmosphere as a 

result of various chemical reactions. 

The health effects associated with 

exposure to PM2.5 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 or work, 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 for PM 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 (μg/m3) and 

a 24-hour standard at a level of 65 μg/ 

m3. 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 of PM2.5 such as 

visibility impairment, soiling, and 

materials damage. 

On October 17, 2006, we revised the 

primary and secondary NAAQS for 

PM2.5 and PM10. In that rulemaking, we 

reduced the 24-hour NAAQS for PM2.5

to 35 μg/m3 and retained the existing 

annual PM2.5 NAAQS of 15 μg/m3. In 

addition, we retained PM10 as the 

indicator for coarse PM, retained the 

existing PM10 24-hour NAAQS of 150 

μg/m3, and revoked the annual PM10

NAAQS (which had previously been set 

at 50 μg/m3). See 71 FR 61236. 

C. Implementation of NSR for PM2.5

After we promulgated the NAAQS for 

PM2.5 in 1997, we issued a guidance 

document entitled ‘‘Interim 

Implementation for the New Source 

Review Requirements for PM2.5’’ (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 of the 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 of the 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 of any 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 of a PM10 program 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 PM2.5 and related 

precursors, the lack of adequate 

modeling techniques to project ambient 

impacts, and the lack of PM2.5

monitoring sites. 

On April 5, 2005, we issued a 

guidance document entitled 

‘‘Implementation of New Source Review 

Requirements in PM–2.5 Nonattainment 

Areas’’ (Stephen D. Page, EPA).6 This 

memorandum provides guidance on the 

implementation of the nonattainment 

major NSR provisions in PM2.5

nonattainment areas in the interim 

period between the effective date of the 

PM2.5 NAAQS designations (April 5, 

2005) and the promulgation date of the 

final NSR regulations reflected in this 

action. Besides affirming the 

continuation of the Seitz guidance 

memo in PM2.5 attainment areas, the 

April 5, 2005 memo recommends that 

until we promulgate the PM2.5 major 

NSR regulations, States should use a 

PM10 nonattainment major NSR program 

as a surrogate to address the 

requirements of nonattainment 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 of that proposal related to 

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 the PSD 

program for PM2.5 including PM2.5

‘‘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 of ambient air impact 

that is considered a ‘‘significant 

contribution’’ to air quality. If the 

modeled maximum ambient impacts of 

a new 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 if the 

existing monitored ambient 

concentration is less than the SMC. This 

final action on the bulk of the major 

NSR program for PM2.5 along with our 

proposed rule on increments, SILs, and 

SMC, when final, will represent the 

final elements necessary to implement a 

PM2.5 PSD program. When both rules are 

promulgated and in effect, the PM2.5

PSD program will no longer use a PM10

program as a surrogate, as has been the 

practice under our existing guidance. 

IV. Overview of This Final Action 

The table below summarizes the main 

elements of the 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 


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

7See ‘‘Implementation of the New Source Review 

(NSR) Program for Particulate Matter Less Than 2.5 

Micrometers in Diameter (PM2.5); Response to 

Comments,’’ U.S. Environmental Protection 

Agency. It can be viewed or downloaded at 

www.regulations.gov, Docket ID No. EPA–HQ–

OAR–2003–0062. 

regulations, is addressed in detail in the 

referenced sections of this preamble. 

NSR program element Final action Section 

Applicability to PM2.5 precursors ............. SO2—Must be regulated as precursor, NOX—Presumed regulated, VOC—Presumed not regulated, Ammonia—Presumed not regulated.V.A 

PSD major source threshold ................... 100/250 tons per year (tpy) .................................................................................... V.B 

NA NSR major source threshold ............ 100 tpy .................................................................................................................... V.B 

Significant emissions rate ....................... Direct PM2.5 emissions—10 tpy, SO2 precursor—40 tpy, NOX precursor—40 tpy, 

if regulated.

V.C & V.D 

Condensable PM2.5 emissions ................ Included in direct PM2.5 emissions for major NSR applicability determinations 

after the end of the transition period (changed based on comments received).

V.E 

Control technology: BACT and LAER ..... Applies for direct PM2.5 emissions, SO2, and other precursors if regulated. V.F.1 & V.G 

Prevention of significant deterioration ..... Increments, SILs and SMCs covered in a separate rulemaking ........................... V.F.2 

Air quality impact analysis ...................... Applies for PM2.5 ..................................................................................................... V.F.3 

Preconstruction monitoring ..................... Applies for PM2.5 (finalizing options 1 & 3) ............................................................ V.F.4 

NA NSR Statewide compliance and alternative siting analyses.Applies for direct PM2.5 emissions and precursors, if regulated ............................ V.G 

NA NSR offsets ....................................... Applies for direct PM2.5 emissions and precursors, if regulated ............................ V.G.1–3 

Interpollutant offsetting ............................ Allowed on a regional or statewide basis; EPA is issuing guidance with recommended regional hierarchies and trading ratios (changed based on comments received).V.G.4 

Transition for PSD ................................... Continues to use PM10 as a surrogate ................................................................... V.H 

Transition for NA NSR ............................ Applies through an approved SIP or through 40 CFR part 51, appendix S .......... V.I 

SIP development period .......................... Clarifies that major NSR does not apply to precursors during the SIP development period in attainment areas (changed based on comments received).V.J 

Tribal concerns ........................................ Cross references to proposed NSR rules for Indian country ................................. V.K 

Minor NSR ............................................... Clarifies that State and local regulatory programs must include PM2.5 requirements for minor sources.V.L 

NSR transport option .............................. Transport classification not available ..................................................................... V.M 

The provisions of the PM2.5 major 

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 of public comments on the 

proposal, along with our responses, can 

be found in the docket for this 

rulemaking.7

A. Applicability of NSR to Precursors of 

PM2.5 in the Ambient Air 

Scientific research has shown that 

various pollutants can contribute to 

ambient PM2.5 concentrations. In 

addition to direct PM2.5 emissions, these 

include the following precursors: 

• Sulfur dioxide (SO2); 

• Oxides of nitrogen (NOX); 

• Volatile organic compounds (VOC); 

and 

• 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 of other 

gaseous reactive species; atmospheric 

conditions including solar radiation, 

temperature, and relative humidity; and 

the interactions of precursors 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 of PM formation processes, 

new information from the scientific 

community continues to emerge to 

improve our understanding of the 

relationship between sources of PM 

precursors and secondary particle 

formation. 

Precursors contribute significantly to 

ambient PM2.5 concentrations, 

producing approximately half of the 

concentration nationally. In most areas 

of the country, PM2.5 precursor 

emissions are major contributors to 

ambient PM2.5 concentrations. The 

relative contribution to ambient PM2.5

concentrations from each of these 

pollutants varies by area. The relative 

effect of reducing emissions of these 

pollutants is also highly variable. 

Some PM2.5 precursors are already 

subject to major NSR under other 

NAAQS, as shown in the following 

table: 

PM2.5

precursor 

Existing program coverage 

for major NSR applicability 

NOX ................ NA NSR and PSD for NO2

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 for regulating precursors to the 

formation of criteria pollutants, and 

then discuss our final action for each of 

the PM2.5 precursors. 

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) of the Act, 

which defines the term ‘‘air pollutant’’

to include ‘‘any precursors to the 

formation of any 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 

of this second sentence in section 302(g) 

explicitly authorizes the Administrator 


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to identify and regulate precursors as air 

pollutants under other parts of the Act. 

In addition, the second clause of the 

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 of the air pollutant 

problem. Likewise, we do not interpret 

the Act to require that EPA treat all 

precursors of a particular pollutant the 

same under any one program when 

there is a basis to distinguish between 

such precursors within that program. 

For example, in a recent rule addressing 

PM2.5 precursors for purposes of the 

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 of the Act. Section 

182 of the 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 of NOX (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 of PM10 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 PM10

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 PM10

ambient concentrations and the need to 

harmonize the regulation of PM10

precursors with other provisions of the 

Act: 

The Committee notes that some of these 

precursors may well be controlled under 

other provisions of the CAA. The Committee 

intends that * * * the Administrator will 

develop models, mechanisms, and other 

methodology to assess the significance of the 

PM10 precursors in improving air quality and 

reducing PM10. Additionally, the 

Administrator should consider the impact on 

ozone levels of PM10 precursor controls. The 

Committee expects the Administrator to 

harmonize the PM10 reduction objective of 

this section with other applicable regulations 

of this CAA regarding PM10 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) of the Act 

clearly calls for the regulation of 

precursor pollutants, but the 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 not be effective 

or appropriate to control a certain 

precursor under a particular regulatory 

program or for EPA to require similar 

control of a particular precursor in all 

areas of the country. 

The term ‘‘air pollutant,’’ as defined 

in section 302(g), is incorporated into 

the NSR provisions for various 

purposes. Thus, we interpret section 

302(g) of the Act to require us to 

consider how to address precursors 

under the NSR program. 

With regard to PSD, section 165(a)(3) 

of the Act states that new or modified 

major sources must demonstrate that 

emissions ‘‘will not cause, or contribute 

to, air pollution in excess of any * * * 

NAAQS in any air quality control region 

* * *.’’ A source could not reasonably 

make this demonstration without 

considering precursors that EPA has 

identified for this purpose. Section 

165(a)(4) of the 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 of the 

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. 

Conversely, where the effect of a 

pollutant’s emissions on ambient PM2.5

concentrations is subject to substantial 

uncertainty, such that in some 

circumstances the pollutant may not 

result in formation of PM2.5, or control 

of the 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 of NSR for PM2.5. We 

discuss our final action with respect to 

each of the 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) of the Act. Section 

110(a)(2)(D) of the 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 of sections 

189(e) and 302(g), we are clarifying that 

the use in this NSR implementation rule 

of the term ‘‘significant contribution’’ to 

the area’s PM2.5 concentration means 

that 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, 

if modeling 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 area 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 of emissions of the precursor 

in the area. Assessments of whether it 

is technically feasible and cost effective 

to control particular emissions units at 

a source should be part of the later 

BACT determination within a permit 

action, and should occur after the basic 

assessment of which precursors are to 

be regulated NSR pollutants in an area 

is completed. 

Most commenters did not question 

our legal authority to identify and 

regulate PM2.5 precursors. However, 

some commenters argued, based on the 

language of sections 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 de minimis 

doctrine of the Alabama Power decision 

or on practical implementation 

considerations such as the uncertainty 

in measuring and modeling the effect of 

PM2.5 precursors. 

We do not agree with the comment 

that the Act does not give us discretion 

to presumptively exclude a PM2.5

precursor from NSR requirements. As 

stated previously, we believe that 

section 302(g) allows the Administrator 

to presumptively not require 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 of this preamble, we 

find that at this time there is sufficient 

uncertainty regarding whether certain 

precursors significantly contribute to 

PM2.5 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, if in the State’s 

NSR program adoption process a 

commenter provides additional 

information suggesting an alternative 

policy for regulating a particular 

precursor, the State 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 of the 

same pollutant differently under the 

same program. 

3. Final Action on SO2

Sulfur dioxide is emitted mostly from 

the combustion of fossil fuels in boilers 

operated by electric utilities and other 

industrial sources. Less than 20 percent 

of SO2 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 of SO2

is an important process affecting most 

areas in North America. There are three 

different pathways for this 

transformation. 

First, gaseous SO2 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 (or fog or 

rainwater), and there it can be oxidized 

to sulfuric acid by a variety of oxidants, 

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 in the 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 SO2 can be oxidized in 

less than an hour. Third, SO2 can be 

oxidized in reactions 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 of SO2

has also been observed on the surfaces 

of black 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 half of the 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, (NH4)2SO4. 

If there is not enough ammonia present 

to fully neutralize the produced sulfuric 

acid (one molecule of sulfuric acid 

requires two molecules of ammonia), 

part of it exists as ammonium bisulfate; 

NH4HSO4 (one molecule of sulfuric acid 

and one molecule of ammonia) and the 

particles are more acidic than 

ammonium sulfate. In certain situations 

(in the absence of sufficient ammonia 

for neutralization), sulfate can exist in 

particles as sulfuric acid, H2SO4. 

Sulfuric acid often exists in the plumes 

of stacks where SO2, sulfur trioxide 

(SO3), 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 PM2.5 concentrations, 

and contributes to other air quality 

problems in all regions of the 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 approach 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 of which require SO2

reductions to address fine particle 

pollution and related air quality 

problems. Finally, we do not believe 

that regulating SO2 as a precursor to 

PM2.5 is likely to add a major burden to 

sources, as SO2 is already regulated as 

part of the NSR program for the SO2

NAAQS. 

Most commenters who addressed this 

issue agreed that SO2 should be 

regulated as a PM2.5 precursor, although 

one only supported regulation of SO2 as 

a precursor in NA NSR, and not under 

PSD. Two commenters disagreed that 

SO2 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 SO2 as a precursor 

unpersuasive. Sulfate is a significant 

fraction of PM2.5 mass in all 

nonattainment areas currently, and 

although large SO2 reductions are 

projected from electric generating units 

with the implementation of the 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 of NOX are numerous and 

widespread. The combustion of fossil 

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 (HNO3) 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 

of aerosol ammonium nitrate is favored 

by the availability of ammonia, 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 of nitrates 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 of 6 to 8 percent of total 

PM2.5 mass, whereas nitrate comprises 

40 percent or more of PM2.5 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 of nearby SO2

emissions because ammonia reacts 

preferentially with SO2 over NOX. 

Reductions in NOX emissions are 

expected to reduce PM2.5 concentrations 

in most areas. However, it has been 

suggested that in a limited number of 

areas, NOX control would result in 

increased PM2.5 mass by disrupting the 

ozone cycle and leading to increased 

oxidation of SO2 to form sulfate 

particles, which are heavier than nitrate 

particles. 

Because of these 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 if the 

State demonstrates to the 

Administrator’s satisfaction or EPA 

demonstrates that NOX emissions in that 

area are not a significant contributor to 

that area’s ambient PM2.5

concentrations. If a 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 PM2.5. 

As discussed previously, this 

‘‘presumed-in’’ approach is warranted 

based on the well-known transformation 

of NOX 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 number of rules targeting onroad and 

nonroad engine emissions. 

We had proposed that NOX be 

presumed to be a precursor in any State 

that EPA has identified as a source of 

the PM2.5 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 for PM2.5 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 not believe 

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, or indicated that a waiver for 

exclusion of NOX as a precursor should 

be allowed only if downwind States 

approve such a waiver. A few 

commenters stated that NOX should not 

be regulated as a precursor to PM2.5 in 

the major NSR program, either on 

grounds of scientific uncertainty 

regarding the impact of NOX 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 not be 

regulated as a PM2.5 precursor because 

it is a regulated pollutant under other 

NAAQS. We do not find the degree of 

scientific uncertainty regarding PM2.5

formation from NOX to be great enough 

to preclude regulation of NOX 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 itself justify 

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 of NOX as a precursor for 

PM2.5 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 PM2.5 is based on the wellknown transformation of NOX 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 of ambient 

particles is a complex mixture of 

hundreds or even thousands of organic 

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 of the 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 of their products. However, 

they participate in atmospheric 

chemistry processes resulting in the 

formation of ozone 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 this reason 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 of SOA 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 of its products. 

In addition, recent work suggests that 

the presence of acidic aerosols may lead 

to an increased rate of SOA 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 of total SOA in some 

airsheds. Man-made sources of 

aromatics gases include mobile sources, 

petrochemical manufacturing, and 

solvents. Some of the biogenic 

hydrocarbons emitted by trees are also 

considered to be important precursors of 

secondary organic PM. Terpenes (and bpinene, limonene, carene, etc.) and the 

sesquiterpenes are expected to be major 

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 of the 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 of the primary and 

secondary components of organic 

aerosol to the measured organic aerosol 

concentrations remains a complex issue. 

Most of the 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 of North 

America. Many studies suggest that the 

primary and secondary contributions to 

total organic aerosol concentrations are 

highly variable, even on short time 

scales. Studies of pollution 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 of SOA, it remains probably 

the least understood component of 

PM2.5. The reactions forming secondary 

organics are complex, and the number 

of intermediate and final compounds 

formed is voluminous. Some of the best 

efforts to unravel the chemical 

composition of ambient organic aerosol 

matter have resulted in quantifying the 

concentrations of hundreds of organic 

compounds representing only 10 to 20 

percent of the total organic aerosol 

mass. For this reason, SOA continues to 

be a significant topic of research and 

investigation. 

Current scientific and technical 

information shows that carbonaceous 

material is a significant fraction of total 

PM2.5 mass in most areas, that certain 

VOC emissions are precursors to the 

formation of SOA, and that a 

considerable fraction of the 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 of specific 

VOC to organic PM mass. 

As a result, this final rule does not, in 

general, require regulation of VOC as a 

precursor to PM2.5 for the 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 PM2.5

concentrations. After such a 

demonstration, the State would regulate 

VOC (or a subset of VOC) as a PM2.5

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 of VOC in that area to assure 

that these emissions do not interfere 

with reasonable further progress or the 

ability of that area to attain or maintain 

the PM2.5 NAAQS. 

We believe that this ‘‘presumed-out’’

approach is appropriate for VOC 

because of the complexity in assessing 

the role of VOC in PM2.5 formation, as 

discussed previously. Where the effect 

of a pollutant’s emissions on ambient 

PM2.5 concentrations is subject to this 

degree of uncertainty, we do not have 

justification to establish a nationallyapplicable presumption that the 

pollutant is a regulated NSR pollutant 

subject to the requirements of NSR for 

PM2.5. Under the circumstances, we 

believe the best policy is to continue to 

regulate VOC under NSR as a precursor 

to ozone in all areas, which will 

potentially provide a co-benefit for 

PM2.5 concentrations despite the 

uncertainty in PM2.5 formation 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 PM2.5 concentrations. 

Note that we intend to regulate high 

molecular weight VOC (with 25 carbon 

atoms or more 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 of such 

‘‘condensables.’’

Most commenters agreed with the 

‘‘presumed-out’’ approach for VOC. One 

commenter said that the role of VOC in 

the formation of PM2.5 is sufficiently 

understood to recommend a ‘‘waiver’’

approach for this pollutant in the same 

way as NOX is treated for PM2.5 in the 

rule. 

As discussed previously, the reactions 

forming secondary organics are complex 

and the number of intermediate and 

final compounds formed is voluminous. 

Some of the best efforts to unravel the 

chemical composition of ambient 

organic aerosol matter have merely been 

able to quantify the concentrations of 

hundreds of organic compounds 

representing only 10 to 20 percent of the 

total organic aerosol mass. For this 

reason, SOA continues to be a 

significant topic of research 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 rules. 


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28330 Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 

8NARSTO (2004) ‘‘Particulate Matter Assessment 

for Policy Makers: A NARSTO Assessment.’’ P. 

McMurry, M. Shepherd, and J. Vickery, eds. 

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. 

6. Final Action on Ammonia 

Ammonia (NH3) 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 may reduce PM2.5 mass 

concentrations, but may also increase 

the acidity of particles 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 of the 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 ammonia and the analytical tools to 

quantify the impacts of reducing 

ammonia emissions on atmospheric 

aerosol formation are both evolving. 

Also, area-specific data are needed to 

evaluate the effectiveness of reducing 

ammonia emissions on reducing PM2.5

concentrations in different areas, and to 

determine where ammonia decreases 

may increase the acidity of particles 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, if a State 

demonstrates to the Administrator’s 

satisfaction that ammonia emissions in 

a specific nonattainment area are a 

significant contributor to that area’s 

ambient PM2.5 concentrations, the State 

would regulate ammonia as a PM2.5

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 of that area to 

attain or maintain the PM2.5 NAAQS. In 

all other nonattainment areas in that 

State and nationally, ammonia would 

not be subject to the NSR program. In 

addition, the action of any State 

identifying ammonia emissions as a 

significant contributor to a 

nonattainment area’s PM2.5

concentrations, or our approval of a 

nonattainment SIP doing so, does not 

make ammonia a regulated NSR 

pollutant for the purposes of PSD 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, if appropriate, to reverse 

the presumption and require ammonia 

to be addressed in that State’s 

nonattainment area plan. 

We elected to finalize the proposed 

approach because of continued 

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 of ammonia emissions 

reductions. In addition, data necessary 

to understand the atmospheric 

composition and balance of ammonia 

and nitric acid in an area are not widely 

available, making it difficult to predict 

the results of potential ammonia 

emission reductions. Ammonia 

reductions may be 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 of these issues, but at 

this time we believe this case-by-case 

approach for nonattainment 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 of these 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 ammonia. 

One of these commenters recommended 

that we recognize the role ammonia 

plays in PM2.5 formation and develop a 

policy to require the minimization and 

mitigation of known 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 PM2.5 precursor 

under any circumstances. Three of these 

commenters stated that if EPA permits 

States to demonstrate that ammonia 

should be regulated as a PM2.5 precursor 

for NSR purposes, we should make clear 

that ammonia emissions from the 

operation of an 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 of these 

commenters stated that the ‘‘presumedout’’ approach would improperly 

delegate our authority to regulate 

ammonia as a PM2.5 precursor to the 

States and would reverse Congress’

requirement to regulate PM precursors 

unless the emissions are not part of the 

problem, instead taking the approach 

that we will ‘‘not regulate unless proven 

to be part of the 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 of ammonia 

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 of PM2.5 in a 

particular nonattainment area, we 

believe that the State should be allowed 

to regulate ammonia emissions under its 

PM2.5 NSR program for that area. 

We do not believe 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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Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 28331 

9See ‘‘NEI–PM2.5 Source Analysis’’ in the docket 

for this rulemaking, Docket ID No. EPA–HQ–OAR–

2003–0062. 

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 of ammonia in the formation of 

PM2.5. We believe that it is prudent to 

continue research on ammonia control 

technologies and the ammonia-sulfatenitrate-SOA equilibrium before 

undertaking a broad 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 SO2 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 of ammonia 

emissions when determining whether to 

regulate ammonia under its PM2.5 NSR 

program for a particular nonattainment 

area. However, we also encourage States 

to be mindful of the potential tradeoff in 

terms of ambient PM2.5 concentrations 

that may be related to reducing 

ammonia emissions from NOX control 

systems. 

B. Major Stationary Source Threshold 

for PM2.5

The major NSR program applies to 

construction of major stationary sources 

and major modifications at major 

stationary sources. A stationary source 

is a ‘‘major source’’ if its actual 

emissions or its potential to emit for a 

specific pollutant equals or exceeds 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) of the Act 

contain definitions of ‘‘major emitting 

facility’’ and ‘‘major stationary source’’

that apply to programs implemented 

under part C and subpart 1 of part D of 

the Act (PSD and NA NSR, 

respectively). Consistent with our 

proposal, these final rules follow these 

definitions for purposes of defining a 

major emitting facility or major 

stationary source that would be 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 of each pollutant identified as 

a PM2.5 precursor for the applicable NSR 

program. Under the final rules, the 

major 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 PM2.5 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 of part D of the 

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 of part D. We do not 

interpret subpart 4 of part D of the Act 

(creating ‘‘serious’’ and ‘‘moderate’’

classifications for PM10 nonattainment 

areas) as applying to PM2.5. 

Although our approach is consistent 

with sections 169 and 302(j) and subpart 

1 of part D of the Act, it results in a 

higher major source threshold in PM2.5

nonattainment areas than the major 

source threshold that applies in some 

PM10 nonattainment areas under subpart 

4 of part D of the Act. This is because 

section 189(b) of the Act establishes a 

70-tpy major source threshold for 

‘‘serious’’ PM10 nonattainment areas 

while ‘‘moderate’’ PM10 nonattainment 

areas apply a 100-tpy major source 

threshold based on the 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 of part D of the Act. 

Our emissions inventory data do not 

indicate that this situation will 

adversely impact attainment of the 

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 of sources that would be 

covered as major sources by a lower 

major source threshold would not 

increase substantially unless the 

threshold were lowered to 20 tpy or 

below. Thus, even if EPA had the 

discretion to adopt a 70-tpy major 

source threshold for PM2.5

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 SIP-approved NSR 

programs. For example, if construction 

of PM2.5 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) of the 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 of major source, as the major 

NSR program is. We reiterate that since 

we do not interpret subpart 4 of the Act 

to apply to PM2.5, we do not believe that 

we have discretion under section 302(j) 

of the Act to define a lower major source 

threshold for pollutants such as PM2.5

that are only subject to subpart 1 of part 

D of the Act. 

Some commenters indicated that State 

minor NSR programs would not be 

sufficient to address such sources due to 

interstate transport and the existence of 

interstate PM2.5 nonattainment areas. 

These commenters indicated that a 

lower major source threshold for PM2.5

sources located in designated 

nonattainment areas should be applied 

uniformly throughout the entire 

nonattainment area, which would not be 

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 of direct PM2.5 emissions 

are generally felt primarily in the local 

area. 

One commenter stated that in order to 

address the impact of high 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 


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28332 Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 

10For additional background on EPA’s 

interpretation of modification and rationale for 

including significant emissions rates in defining major modifications, see 61 FR 38253–54 (Dec. 31, 

2002). 

subparts 2 and 4 of part D of the Act, 

which define lower major source 

thresholds for certain classifications of 

ozone and PM10 nonattainment areas, 

respectively. The commenter argued 

that it is unreasonable for us to assert 

that subpart 4 does not apply to this rule 

because it regulates all PM with a 

diameter of less than 10 micrometers, 

which includes PM2.5. The commenter 

believes that we recognized as much in 

our proposal preamble discussion of the 

options for implementing reasonably 

available control technology (RACT), 

where we discussed potential 

approaches that ‘‘would be consistent 

with the approach set forth in the Act 

in subpart 4.’’ 70 FR 66017. This 

commenter stated that a reasonable 

interpretation of the Act requires major 

sources of direct PM2.5 emissions and 

precursor emissions to be defined at a 

baseline level of 70 tpy, and adjusted 

further downward as appropriate 

considering the characteristics and 

potential impacts of the pollutants. 

We do not agree that subpart 4 of part 

D applies to PM2.5 nonattainment areas. 

Subpart 4 was added to the Act by 

Congress specifically to address the 

PM10 NAAQS. We believe that the PM2.5

standard should be implemented under 

subpart 1 of part D, which is the general 

provision of the Act related to NAAQS 

implementation. Part D of title I of 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 PM10

standard. In general, the emphasis in 

subpart 4 on reducing PM10

concentrations from certain sources of 

direct PM2.5 emissions can be somewhat 

effective in certain PM2.5 nonattainment 

areas but not in all. Contributions to 

PM2.5 concentrations 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, 

PM2.5 differs from PM10 in terms of 

atmospheric dispersion characteristics, 

chemical composition, and contribution 

from regional transport. 

A group of environmental 

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 of RACT, 

while we discussed developing a 

classification system for PM2.5

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 of RACT 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 of part D of the Act. 

One commenter stated that the major 

source threshold for PM2.5 emissions 

should be calculated using the current 

SO2 and NOX definitions of major 

source and significant emissions rate. 

Specifically, the commenter suggested 

that the ratio of these values (100 tpy 

and 40 tpy, respectively) should be 

multiplied by the significant emissions 

rate for direct PM2.5 emissions (10 tpy; 

see section V.C following) to yield a 

PM2.5 major source threshold of 25 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 of part D of 

the Act. In any case, the major source 

thresholds and significant emissions 

rates for SO2 and NOX were not defined 

in relation to one another, and therefore 

their relationship would not provide a 

suitable basis for developing the PM2.5

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. Significant Emissions Rate for Direct 

Emissions of PM2.5

The determination of what should be 

classified as a modification subject to 

major NSR is based, in part, on a 

‘‘significant emissions rate.’’ 10 The 

major NSR regulations define this term 

as a rate above which a net emissions 

increase will trigger major NSR 

permitting requirements, if the increase 

results from a major modification. 

Sources are exempt from major NSR 

requirements if the emissions increase 

resulting from a modification is below 

this rate because EPA considers such 

lower emissions increases to be de 

minimis for purposes of the major NSR 

program. 

The significant emissions rates for the 

criteria pollutants other than PM2.5 are 

given in the 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, PM10 emissions. 

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

SO2 ..................................................................... 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 emissions of PM2.5, these 

final rules define the significant 

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 

significant emissions rates for PM 

emissions and PM10 emissions. 

Historically, the original significant 

emissions rate for PM (25 tpy of PM 

emissions) was set using a modeling 

analysis to determine the amount of PM 

emissions that a source could emit that 


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Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 28333 

11The EPA established the original NAAQS for 

PM in terms of ambient concentrations of TSP (40 

CFR 51.100(ss)). Source applicability for PM was 

determined in terms of amounts of PM 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 ambient indicator to be a regulated NSR 

pollutant. The EPA is currently evaluating whether 

it remains 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 PM10 and PM2.5. However, 

PM emissions, based on in-stack measurements, 

continue to be regulated under PSD because of the 

use of such emissions for evaluating compliance 

under a variety of CAA section 111 new source 

performance standards (40 CFR part 60). Given the 

regulatory changes and positions taken by EPA 

since 1993, EPA is re-evaluating the implications 

for PM emissions in the NSPS program (and other 

air programs) and will act accordingly to clarify this 

issue in the near-term. 

would be unlikely to cause ambient 

impacts above 4 percent of the PM 

NAAQS (measured as total suspended 

particulate (TSP)).11 Although a range of 

source configurations can yield a wide 

range of impacts per tpy of emissions, 

our review of typical 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 of TSP by 

more than 4 percent of the 24-hour TSP 

NAAQS. Subsequently, when we set the 

significant emissions rate for PM10, we 

adjusted the rate for PM emissions using 

the ratio of the 24-hour PM10 NAAQS to 

the 24-hour TSP NAAQS to derive the 

PM10 significant emissions rate of 15 

tpy. We used the ratio of 24-hour 

NAAQS for this adjustment because that 

NAAQS was controlling for both PM 

and PM10. 

We used a conceptually 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 of emissions. 

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 

methodology was too conservative, and 

suggested a significant emissions rate of 

15 tpy. Two commenters suggested that 

we use significant emissions rate of 5 

tpy or less. Another commenter 

suggested that we could ‘‘split the 

difference,’’ using an option that could 

give States and companies some 

flexibility: Modifications less than 5 tpy 

of direct PM2.5 emissions could be 

considered de minimis; modifications 

between 5 and 15 tpy of direct 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 of direct PM2.5 emissions 

would be subject. 

We agree with commenters who 

indicated that we were correct in using 

the same methodology for direct PM2.5

that was used to set the significant 

emissions rate for PM10 and PM 

emissions. We do not agree that using 

the same level as PM10 emissions (15 

tpy) is warranted, given the 

demonstrated health effects of PM2.5. 

Neither do we agree that a significant 

emissions rate of 5 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 for the SER of 10 tpy is not 

affected by the nature of the direct PM2.5

emissions (i.e., condensable or not). 

We also do not agree that the 

proportions of primary 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 of a source of direct PM2.5

emissions that would be expected to 

have an ambient impact of 4 percent or 

more of the NAAQS. This relationship 

holds true regardless of the origin of the 

particles that make up the ambient 

PM2.5. The commenter’s approach (i.e., 

carrying out the analysis based on onehalf of the NAAQS because primary 

PM2.5 makes up only one-half of the 

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 of secondary PM2.5. We 

do not believe that this is a reasonable 

approach. 

D. Significant Emissions Rates for PM2.5

Precursors 

Consistent with the preferred option 

in the proposal, we are setting 

significant emissions rates for PM2.5

precursors at the levels for those 

pollutants already included in major 

NSR programs, as shown in the 

following table: 

PM2.5

precursor 

Significant emissions 

rate (equal to or 

exceeding) 

SO2 ........................... 40 tpy. 

NOX .......................... 40 tpy. 

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

Ammonia ................... Adopted in SIP. 

VOC is presumed not to be a 

precursor to PM2.5 in any attainment or 

unclassifiable area, unless the State 

demonstrates to the Administrator’s 

satisfaction or EPA demonstrates that 

emissions of VOC from sources in a 

specific area are 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 of ammonia is a 

necessary part of a 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. See 40 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 of ammonia 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 rate because of the 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 of reducing ammonia 

emissions on ambient PM2.5

concentrations. In addition, we note that 

the SIP revisions that States undertake 

to add ammonia to their NA NSR 


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12Leter from Thompson G. Pace, Acting Chief, 

Particulate Matter Programs Branch, to Sean 

Fitzsimmons, Iowa Department of Natural 

Resources (Mar. 31, 1994) (available at http:// 

www.epa.gov/Region7/programs/artd/air/ 

nsr.nsrmemos/cpm.pdf and in the docket for this 

rulemaking, Docket ID No. EPA–HQ–OAR–2003–

0062). 

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 other purposes in the 

NSR program. One commenter indicated 

that since roughly half or more of 

ambient PM2.5 is derived from 

precursors, 10 tpy would be an 

appropriate significant emissions rate 

for PM2.5 precursor emissions. Another 

commenter suggested a significant 

emissions rate of 4 tpy for SO2 and 2 tpy 

for NOX, 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 SO2 and 

NO2 annual NAAQS. Since the ambient 

concentrations of PM2.5 vary across the 

country and since significant emissions 

rates have not been 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 existing 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 of proposed 

modifications by reference to a single 

significant emissions rate for each 

pollutant, and enables streamlining of 

determinations regarding the applicable 

control technology and analysis of air 

quality impacts into a single and 

comprehensive decision making process 

for both 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 of the precursors on PM2.5

concentrations. It is difficult to 

determine the ambient air quality effects 

that result from a single source of 

emissions of PM2.5 precursors. There are 

conservative screening models for 

predicting impacts of large NOX and 

SO2 sources on ambient PM2.5

concentrations. We conducted a range of 

modeling analyses to determine the 

amount of PM2.5 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 at this time does not 

provide sufficient information to 

estimate impacts of emissions from 

individual sources of ammonia and 

VOC on ambient PM2.5 concentrations. 

While we know that precursors 

contribute to the formation of PM2.5 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 of particle 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 of setting the significant 

emissions rates for SO2, NOX, and VOC 

for purposes of the PM2.5 NSR program 

at the same levels that are already used 

for other purposes in the major NSR 

program. 

E. Condensable PM Emissions 

In this final NSR rule, EPA will not 

require that States address condensable 

PM in establishing enforceable 

emissions limits for either PM10 or PM2.5

in NSR permits until the completion of 

a transition period, as described herein. 

In response to significant comments on 

the variability of test methods available 

for measuring condensable emissions, 

we have adopted this transition period 

approach to allow us to assess the 

capabilities of the 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 of the 

test methods assessment, EPA will be 

conducting a notice and comment 

rulemaking to codify new or revised test 

methods. Once these new or revised test 

methods are in place, States will have 

the tools necessary to issue NSR permits 

addressing condensable PM. Thus, as 

part of the test methods rulemaking, we 

will take comment on an earlier closing 

date for the transition period in the NSR 

program if we are on track to meet our 

expectation to complete the test 

methods rule much earlier than January 

1, 2011. In the meantime, however, we 

are establishing January 1, 2011 as the 

latest possible end date for the NSR 

transition period because this is also the 

end of the 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 of this 

NSR implementation rule but prior to 

the end of the transition period for the 

NSR program are not required to 

account for condensable emissions in 

PM2.5 or PM10 emissions limits. After 

January 1, 2011 (or any earlier date 

established in the upcoming rulemaking 

codifying test methods), EPA will 

require that NSR permits include limits 

of condensable emissions, as 

appropriate. Prior to this date, States are 

not prohibited from establishing 

emissions limits in NSR permits that 

include the condensable fraction of 

direct PM2.5. 

As noted in the proposal preamble, 

certain commercial or industrial 

activities involving high temperature 

processes (e.g., fuel combustion, metal 

processing, and process cooking 

operations) emit gaseous pollutants into 

the ambient air, some of which rapidly 

condense into particle form. The 

constituents of these condensed 

particles include, but are not limited to, 

organic materials, sulfuric acid, and 

metals and metal compounds. We 

consider such condensable emissions to 

be a component of direct PM emissions. 

Specifically, direct PM emissions 

consist of both the ‘‘filterable fraction’’

which already exist in particle form at 

the elevated temperature of the exhaust 

stream, and the ‘‘condensable fraction’’

which exist in gaseous form under 

exhaust stream conditions but 

condenses rapidly in the ambient air. 

Because condensable PM emissions 

exist almost entirely in the 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 PM2.5 emissions. Therefore, we 

believe that it is important that the air 

quality management of PM promote a 

comprehensive approach to the control 

of condensable PM. 

We proposed on November 1, 2005 to 

clarify that condensable PM emissions 

must be 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 PM10 includes condensable PM and 


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that, where States expect condensable 

PM emissions to be in higher 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 (see 67 FR 39602, 

June 10, 2001) and that Method 202 in 

appendix M of 40 CFR part 51 quantifies 

condensable PM. We also noted that 

States have not applied this existing 

guidance consistently. 

We received a number of comments 

on whether NSR programs should 

account for condensable PM emissions 

in light of the current state of knowledge 

of and uncertainties around the 

measurement of direct PM2.5. Several 

commenters supported our proposal to 

require the inclusion of condensable 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 of test 

methods and related issues about the 

uncertainties in existing data for 

condensable PM2.5. As a result of the 

concerns, these commenters believed 

EPA would be premature in requiring a 

comprehensive evaluation of 

condensable PM2.5, 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, 

expeditious attainment of the PM2.5

standard. Another commenter expressed 

concern about the potential for 

retroactive enforcement over 

applicability decisions made in good 

faith, and for retroactive 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/estimating 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 of condensable 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 of these 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 of condensable 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 of the 

available or revised test methods. The 

purpose of the 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 PM2.5 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 of the transition period, 

insofar as the quantity of condensable 

PM emissions are concerned, unless the 

applicable implementation plan clearly 

required consideration of condensable 

PM. Likewise, EPA will interpret PM 

emissions limitations in existing 

permits or permits issued during the 

transition period as not requiring 

quantification of condensable PM2.5 for 

compliance purposes unless such a 

requirement was clearly specified in the 

permit conditions or the applicable 

implementation plan. 

After the end of the 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 PM10

address condensable emissions as 

applicable, and the source may not rely 

on calculations made for previous 

determinations that did not include an 

accurate accounting of condensables. 

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 will be 

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 of the transition 

period as it applies to the other 

elements of the air program in the final 

Clean Air Fine Particle Implementation 

Rule. 

Although EPA is not requiring that 

State NSR programs address 

condensable emissions of PM until the 

end of the transition period, States that 

have developed the necessary tools are 

not precluded from acting to measure 

and control condensable PM emissions 

in NSR permit actions prior to the end 

of the 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 of condensable PM2.5

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 of total 

PM emissions from a source. 

F. Prevention of Significant 

Deterioration (PSD) Program 

Requirements 

To receive a permit for a new major 

source or a major 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). 

• As required, comply with 

preconstruction monitoring 

requirements. 

This final action regarding each of these 

elements is discussed in the following 

sections. 


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1. How must BACT be implemented for 

PM2.5? 

We are not making any change to our 

current regulations or policy for 

implementing BACT requirements at a 

major source that is subject to the 

requirements of the PSD program. 

Accordingly, if a new major source will 

emit, or have the potential to emit, a 

significant amount of a 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, if a physical or 

operational change at an existing major 

source will result in a significant 

emissions increase and a significant net 

emissions increase of a 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 of the 

physical or operational change in the 

unit. Under the PM2.5 PSD program, 

these requirements will apply to direct 

PM2.5 emissions; SO2 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 of the 

PM2.5 PSD program when we finalize 

that proposed rule. 

3. What is the ambient air quality 

analysis requirement for PM2.5? 

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 a PSD increment 

or NAAQS violation. See section 

165(a)(3) of the 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 of the 

PM2.5 NSR program. Accordingly, 

sources will be required to perform this 

analysis for the PM2.5 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 

PM2.5 monitor locations, as well as at 

other locations that are appropriate for 

comparing predicted PM2.5

concentrations to the NAAQS based on 

PM2.5 monitor 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) of the 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: 

• The maximum modeled 

concentration for the applicable 

averaging period caused by the 

proposed significant emissions increase 

(or net emissions increase) is less than 

the prescribed SMC; or 

• 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 of the 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 1 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 of new PM2.5

monitors and redundant 

preconstruction monitoring. 

Another commenter, however, 

believed option 1 to 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 for these areas. 

Additionally, one group of commenters 

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 commenter that 

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 of an SMC as screening tool for 

identifying when an impact is de 

minimis and there is thus little or no 

value in gathering preconstruction 

monitoring data The use of de minimis 

levels of this nature (such as significant 

emission rates and significant impact 

levels) is supported by court precedent 

interpreting the NSR provisions of the 

Act. Alabama Power Co. v. Costle, 636 

F.2d 323, 360 (DC Cir. 1979). (‘‘Unless 

Congress has been extraordinarily rigid, 

there is likely a basis for an implication 

of de minimis authority to provide [an] 

exemption when the burdens of 

regulation yield a gain of trivial 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 

for both 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 


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13These 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) of those provisions in the December 31, 

2002 NSR reform rule and inadvertently overlooked 

correcting the cross-references in paragraphs 

(i)(5)(ii) and (i)(5)(iii). See 67 FR 80186. As 

proposed, in this final action we have corrected this 

misnumbering and others in this section. 

commenters noted that spatial gradients 

can be significant for PM2.5, 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 PM2.5

monitoring record has the following 

limitations: 

• The PM2.5 monitoring data record 

would require spatial interpolation 

between monitors for the determination 

of appropriate concentrations at the 

project’s location. 

• Use of existing monitored data will 

not increase the PM2.5 monitoring data 

record to confirm or contradict 

conventional perceptions. 

• The PM2.5 monitoring data record 

assumes that local hot spots of high 

PM2.5 concentrations do not exist or are 

already being monitored, which may not 

be true in all cases. 

• Automatic acceptance of existing 

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 to justify 

the exclusion of preconstruction 

monitoring requirements when source 

impacts are less than the SMC or when 

sufficient representative data exists. One 

group of commenters 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 of public 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 minimis exemption 

from monitoring requirements is 

supported by court precedent 

interpreting the PSD provisions of the 

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 

PM10 data record combined with the 

recently acquired PM2.5 data to provide 

representative ambient measurements 

for most sources. One comment 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 of PM2.5

monitoring (e.g., with sufficiently 

protective assumptions about PM2.5/ 

PM10 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 of attempting 

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 PM10

and our limited understanding of their 

relationship are problematic for this 

application. We do not believe that 

generalized factors to convert PM10

concentrations to PM2.5 concentrations 

sufficiently reflect important industryspecific and spatially-related 

characteristics of PM2.5. In addition, 

removing altogether the obligation to 

provide preconstruction PM2.5 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 of pollutants for which SMC have 

been set.13 The original rationale for this 

exemption is based on the lack of 

adequate methods for measuring 

ambient concentrations of pollutants not 

on the list. See 45 FR 52709, 52723–

52724. We requested comment on this 

interpretation and any other legal or 

policy rationale that could support 

applying the text of these 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 of options 1 and 3 from the 

proposal, since we believe that it 

reflects existing procedures for other 

regulated NSR pollutants. Once we 

finalize an SMC for PM2.5, the reviewing 

authority will have the discretion to 

exempt a source from the 

preconstruction monitoring requirement 

if the projected PM2.5 ambient impact of 

the source is below the PM2.5 level 

promulgated in our rules. In addition, 

additional preconstruction monitoring 

data may not be necessary based on the 

availability of existing representative 

monitoring data in the area, as 

discussed previously. 

G. Nonattainment New Source Review 

(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; 


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• 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 of these 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 of PM2.5

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, and that 

is consistent with reasonable further 

progress towards attainment. We refer to 

the proportional difference between the 

amount of the required offsets to the 

amount of emissions increase as the 

‘‘offset ratio.’’

The Act specifies an offset ratio for 

several situations. In ozone 

nonattainment areas subject to subpart 2 

(of title I, part D of the Act), the ratio 

is set between 1.1:1 and 1.5:1 depending 

on the area’s level of classification 

pursuant to subpart 2. For other 

nonattainment areas, the Act establishes 

a minimum offset ratio of 1:1 pursuant 

to subpart 1 of title I, part D of the Act. 

As proposed, we are finalizing the 

offset ratio for direct PM2.5 emissions as 

at least 1:1 on a mass 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 

would be 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 of how ground-level 

PM2.5 emission reductions could be 

achieved. We do not believe that a lower 

offset ratio is authorized under subpart 

1, which prescribes an offset ratio of at 

least 1:1, and therefore we have not 

adopted this approach in our final rules. 

Some of the commenters disagreed 

regarding whether an offset ratio of at 

least 1:1 under subpart 1 represents a 

ceiling or a floor on the level we can 

prescribe in our regulations. We 

interpret section 173 of the Act to 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 if they wish, but we do 

not believe that it would be appropriate 

for us to do so for PM2.5 in national 

regulations. We do not have cause to 

believe a higher ratio is necessary for 

PM2.5 in each area of the country and 

prefer to leave this to the discretion of 

States. We do not believe that the higher 

offset ratios required for ozone 

precursors under subpart 2 apply in any 

way to direct PM2.5 emissions or PM2.5

precursors. 

2. Which precursors are subject to the 

offset requirement? 

Consistent with our proposal, the 

pollutants that are designated as PM2.5

precursors in a particular area are 

subject to the offset requirement in that 

area. Accordingly, SO2 is subject to 

offsets in all PM2.5 nonattainment 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 in a particular area are 

not a significant contributor to that 

area’s ambient PM2.5 concentrations. As 

‘‘presumed-out’’ precursors, VOC and 

ammonia would be subject to offsets 

only in areas where the State has 

demonstrated that these emissions are 

significant contributors to the area’s 

ambient PM2.5 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 of all precursors 

that have been established to contribute 

to the PM2.5 nonattainment 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 of the 

Act is at least 1:1. Based on these 

requirements of the 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 of a PM2.5 precursor with 

creditable reductions of the same 

precursor. This offset ratio applies for 

all pollutants that have been designated 

as PM2.5 precursors in a particular 

nonattainment area. 

Most commenters agreed with this 

approach. A few commenters indicated 

that an offset ratio of less than 1:1 for 

precursor emissions of PM2.5 should be 

allowed only if there is a net air quality 

benefit and if the lower ratio is justified 

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 of determining the impacts of 

the precursor emissions on the air 

quality in the nonattainment area in 

which the source is located. As noted 

previously, we do not believe 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 of the health risks associated 

with PM2.5, EPA must require offsets of 

at least 1.15:1 for PM2.5 precursors in 

‘‘moderate’’ nonattainment areas, and 

must increase the offset ratio in 

‘‘serious’’ nonattainment areas or in 

areas that request extensions of their 

attainment deadlines. As mentioned 

previously, we do not believe that 

subpart 2 of the Act (which includes 

section 182) has any relevance to PM2.5

or its precursors. Subpart 2 is specific to 

ozone. In addition, we are implementing 

the PM2.5 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 of offsets for NOX emissions if 

NOX is regulated as a precursor both for 

ozone and PM2.5 in the area. The NOX

precursor emissions need only be offset 

once in accordance with the applicable 


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Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 28339 

14A full description of this approach is available 

in the technical support document at http://www.

epa.gov/scram001/reports/pmnaaqs_tsd_rsm_all_

021606.pdf and in the docket for this rulemaking, 

Docket ID No. EPA–HQ–OAR–2003–0062. 

15Available in the docket for this rulemaking, 

Docket ID No. EPA–HQ–OAR–2003–0062. 

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 of NOX offsets. 

4. Is interpollutant trading allowable to 

comply with offset requirements? 

In this final rule, we are allowing 

limited interpollutant trading for 

purposes of offsets 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 NA NSR permitting 

process. For the purpose of offsets in the 

NA NSR program for PM2.5, the final 

rules allow reductions in direct PM2.5

emissions to offset precursor emissions 

increases, emissions reductions of one 

precursor to offset emissions increases 

of another precursor, and reductions in 

precursor emissions to offset direct 

PM2.5 emissions increases. 

We have completed a technical 

assessment to develop preferred 

interpollutant trading ratios that may be 

used for the purposes of PM2.5 offsets, 

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 of direct 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 PM2.5 control strategies as part 

of the Regulatory Impact Assessment 

(RIA) for the final PM2.5 NAAQS.14

Based on results from the RSM, we 

determined the distribution of predicted 

ratios for urban areas and regions across 

the country and developed the preferred 

ratios with a goal 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 

Trading Ratios for PM2.5 Offsets.’’ 15 Use 

of the preferred ratios is recommended 

by EPA but not mandatory, and we do 

not intend to preclude the opportunity 

for a local demonstration of trading 

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 of emissions reductions 

varies across pollutants and that a ton 

of direct PM2.5 is generally more 

effective than a ton of precursor 

emissions in reducing overall PM2.5

concentrations. For the purposes of 

reporting information here, we define 

the ‘‘East’’ to be the 37 States either 

completely or in part east of 100 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 SO2; SO2 to NOX: Our 

assessment indicated potential disbenefits of 

reducing NOX (i.e., reducing NOX tons in 

urban areas may increase overall PM2.5

concentrations) in the eastern United States 

and urban areas in the western United States. 

Due to the possibility of these disbenefits and 

the high degree of variability in the observed 

NOX to SO2 ratios or SO2 to NOX ratios across 

urban areas, we are not defining preferred 

ratios involving trades between these 

precursors but will rely upon 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 

PM2.5 concentrations (i.e., no disbenefits from 

NOX reductions as noted previously), our 

assessment indicates that the preferred 

trading ratio is 200 to 1 (NOX tons for PM2.5

tons) or 1 to 200 (PM2.5 tons for NOX tons) 

for areas in the eastern United States, and 

100 to 1 (NOX tons for PM2.5 tons) or 1 to 100 

(PM2.5 tons for NOX tons ) for areas in the 

western United States. 

3. SO2 to Primary PM2.5; Primary PM2.5 to 

SO2: We have determined a nationwide 

preferred ratio of 40 to 1 (SO2 tons for PM2.5

tons) or 1 to 40 (PM2.5 tons for SO2) for trades 

between these pollutants. We recognize there 

is spatial variability here between urban and 

regionally located sources of these pollutants 

that can be addressed through a local 

demonstration to determine an area-specific 

relationship, as appropriate. 

We recommend that States use these 

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 for PM2.5 NSR 

offsets. If States elect to use EPA’s 

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 of the 

net air quality benefit for PM2.5 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 a number 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., SO2

and NOX) 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 of the 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 of the limitations of existing air 

quality models. We believe that the 

regional-scale models used for areawide attainment 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, only to yield limited results. 

For these reasons, the final rules only 

allow a State to develop its own 

interpollutant trading rule for inclusion 

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 will be 

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 SO2. 


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28340 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 of viewpoints. Several 

commenters supported flexible 

interpollutant trading at ratios 

established either on an area-wide basis 

or permit by permit. They often pointed 

out the economic and administrative 

benefits of flexibility 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 

of enterprises 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 PM2.5 emissions 

typically have a more local impact, 

while the impact of precursor emissions 

are farther afield. A number of 

commenters pointed out the complex 

atmospheric chemistry of secondary 

particulate formation and the 

shortcomings of the 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 PM2.5 emissions 

raises serious environmental justice 

concerns due to the localized impacts of 

direct PM2.5 emissions. 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 of SO2 and NOX; and formation 

of ozone, acid deposition, and reactive 

nitrogen deposition. 

We also received comments opposing 

allowing interpollutant trading for 

netting purposes, on the basis that the 

resulting program would be very staffintensive apart from the difficulty of 

demonstrating through modeling the net 

air quality benefit of a single source 

trade. We concur with these 

commenters and are not allowing 

interpollutant trading for netting 

purposes at this time. 

A number of commenters supported 

some types of trades, 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, SO2, NOX, ammonia, 

and VOC. That is, a pollutant 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 

of the listed pollutants, SO2 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 adopt EPA’s recommended 

trading ratios or be backed up by 

regional-scale modeling that 

demonstrates a net 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 SO2, in many areas. 

H. How will the transition to the PM2.5

PSD requirements occur? 

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 of the 

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 of the 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 of any 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 

of a PM10 program 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 PM2.5 and 

related precursors, the lack of adequate 

modeling techniques to project ambient 

impacts, and the lack of PM2.5

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 implementation 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 of 40 CFR 52.21 to 

those States without approved PSD 

programs (typically referred to as 

‘‘delegated States’’). Except as provided 

in the grandfathering provisions that 

follow, these final rules go into effect 

and must be implemented beginning on 

the effective date of this rule, 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 on PM from the PM10

requirements established in 1987, EPA 

will allow sources or modifications who 

previously submitted applications in 

accordance with the PM10 surrogate 

policy to remain subject to that policy 

for purposes of permitting if EPA or its 

delegate reviewing authority 

subsequently determines the application 

was complete as submitted. This is 

contingent upon the completed permit 

application being consistent with 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 PM10 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 are contained 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 ‘‘SIPapproved 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 


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16 In 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 of the time it has taken to 

complete this final rule, expecting States to submit 

required SIP revisions consistent with this final rule 

by April 5, 2008 is no longer practical or fair. 

Nevertheless, States are still currently required to 

implement a PSD program for PM2.5, and we still 

expect States to fulfill the SIP infrastructure 

requirements of CAA section 110(a)(2), including 

the PSD program requirements, by April 5, 2008. 

We believe these PSD program requirements are 

currently met by implementing the transitional PSD 

program for PM2.5 described in this preamble (a.k.a. 

the PM10 surrogate policy). In accordance with a 

Consent Decree in Environmental Defense and 

American Lung Ass’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 the PM2.5 PSD program 

required under section 110(a)(2) of the 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). 

promulgating 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. We nonetheless 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 final rule 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 of this action.16

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 1 that if a SIP-approved 

State is unable to implement a PSD 

program for the PM2.5 NAAQS based on 

these final rules, the State may continue 

to implement a PM10 program as a 

surrogate to meet the PSD program 

requirements for PM2.5 pursuant to the 

1997 guidance mentioned previously. 

Under option 1 for SIP-approved States, 

we had proposed two additional 

requirements. These were to require 

sources to demonstrate that emissions 

from construction or operation of the 

facility will not cause or contribute to a 

violation of the PM2.5 NAAQS and to 

include condensable PM emissions in 

determining major NSR applicability 

and control requirements. We are not 

finalizing either of these additional 

requirements of our proposed option 1. 

We have dropped the requirement for 

demonstrating compliance with the 

PM2.5 NAAQS in order to maintain 

consistency in the application of the 

existing surrogate policy across the PSD 

program during the interim period. 

Since in the final rule we are otherwise 

allowing SIP-approved States to 

continue with the existing PM10

surrogate policy to meet the PSD 

requirements for PM2.5, partially 

implementing the PM10 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 PM10 surrogate 

policy which only recommends as an 

interim measure that sources and 

reviewing authorities conduct the 

modeling necessary to show that PM10

emissions will not cause a violation of 

the PM10 NAAQS 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 PM2.5 program 

until the end of the transition period to 

validate test methods discussed in 

section V.E of this preamble. 

In our proposal, we offered two 

additional options 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 of 40 CFR 52.21 

would govern the issuance of major NSR 

permits during the SIP development 

period. Finally, under option 3, we 

would have allowed a State to request 

delegation of just 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 PM2.5 by 

informing us that it did not intend to 

submit a PSD SIP for PM2.5 in 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 concerns with test 

methods were resolved. One of these 

commenters favored continuing to 

implement the PM10 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 

make 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 of these suggested 

that we issue updated guidance to 

incorporate these PSD requirements for 

PM2.5, while one preferred that we 

revise appendix S to 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 of these 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 of the full PSD 

program are in place to ensure that there 

is no significant deterioration in air 

quality. Another commenter stated that 

none of the proposed options were 

viable for their State. The commenter 

requested that we allow States to 

continue their existing PM10 program as 

a surrogate for PM2.5, without caveat. 

As noted previously, we are finalizing 

proposed option 1, without the 

requirement of demonstrating 

compliance with the PM2.5 NAAQS or 

the requirement to include condensable 

emissions. We believe that our final rule 

is reasonable for the following reasons. 

First, PM10 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 for PM2.5 would also 

trigger PM10 requirements because PM2.5

is a subset of PM10. Second, both of the 

precursors designated in the final rule—

SO2 and NOX (presumptively)—are 

already regulated under State NSR 

programs for other criteria pollutants. 

Thus, those precursors will be subject to 

NSR through those other programs. We 

do not believe that the other options or 

suggestions offer significant advantages 

that outweigh the utility and ease of 

implementation of this approach. 

States may include grandfathering 

provisions similar to the ones EPA 


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17As discussed earlier, we are following the 

precedent we established in our 2002 rule for NA 

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 of this rule to be submitted by April 5, 

2008, as we had proposed. However, the States are 

still required to submit nonattainment plans for 

PM2.5 (including NA NSR programs) on April 5, 

2008. We believe this requirement is satisfied by 

implementing the transitional NA NSR program for 

PM2.5 (a.k.a. the PM10 surrogate policy) described in 

our April 5, 2005 guidance, or, if submitted after 

the effective date of this 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 to comply with 

nonattainment area requirements under Part D. 

included in the transition requirements 

for 40 CFR 52.21. 

I. How will the transition to the PM2.5

NA NSR requirements occur? 

1. Background 

The requirements for State NA NSR 

programs are contained in 40 CFR 

51.165. All States with nonattainment 

areas have developed NA NSR programs 

according to these requirements, which 

we have approved into each State’s 

implementation plan. However, as 

noted previously, it takes time for a 

State to amend its SIP 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 NSR 

program for a particular pollutant, 

appendix S of 40 CFR part 51 applies for 

NA NSR permitting. 

Section 172(c)(5) of the Act requires 

that States issue major NSR permits for 

construction and major modifications of 

major stationary sources in any 

nonattainment area. Thus, since the 

PM2.5 nonattainment designations 

became effective on April 5, 2005, States 

are now required to issue major NSR 

permits that address the section 173 NA 

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 of the NA NSR 

program pending the completion of this 

action to develop implementation rules 

for PM2.5. See memorandum from 

Stephen D. Page, Director, Office of Air 

Quality Planning and Standards to 

Regional Air Directors, ‘‘Implementation 

of New Source Review Requirements in 

PM2.5 Nonattainment Areas’’ (April 5, 

2005). 

Our current guidance permits States 

to implement a PM10 NA NSR program 

as a surrogate to address the 

requirements of NA 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 for PM10 or 

implementation of a major NSR program 

for PM10 under the authority in 40 CFR 

part 51, appendix S. 

2. Transition 

With this finalization of the new 

PM2.5 NSR implementation 

requirements under 40 CFR 51.165, 

States now have the necessary tools to 

implement a NA NSR program for PM2.5. 

After the effective date of the amended 

rule (that is, July 15, 2008, States will 

no longer be permitted to implement a 

NA NSR program for PM10 as a surrogate 

for the PM2.5 NA NSR requirements. 

Most States will then need to implement 

a transitional PM2.5 NA 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 not believe it is 

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 PM10. 

The NA NSR provisions in a State’s 

existing SIP-approved NA NSR program 

would also apply in areas designated as 

nonattainment for the PM2.5 NAAQS if 

the SIP-approved regulations contain a 

generic requirement to issue part D 

permits in areas designated as 

nonattainment for any criteria pollutant 

and do not otherwise need to be 

amended to incorporate the changes 

finalized in this action. States belonging 

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 from the date 

of this 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 

NSR applies (i.e., the list does not 

include the designated nonattainment 

areas for PM2.5). 

• 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 SIPs are revised to meet 

these new PM2.5 NSR requirements 

under 40 CFR 51.165. 

3. Implementation of NSR 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 will not 

interfere with the area’s progress toward 

attainment. Readers should refer to 

appendix S for a complete 

understanding of these 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 for PM2.5, including 

significant emissions rates applicable to 

major modifications for PM2.5 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 for PM2.5. Appendix S applies 

directly to new and modified major 

stationary sources. In accordance with 

the requirements of section 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. 

If a State is unable to apply the 

requirements of appendix S, we will act 

as the reviewing authority for the 

relevant portion of the permit. We 

believe that it is appropriate for EPA 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 permits 

for those projects meeting the applicable 

criteria during the interim period. See 

the preamble of the proposal for this 

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 of NA NSR 

permits under appendix S during the 

SIP development period. Two of these 


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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 of existing direct PM2.5

emissions and SO2 offsets likely will 

make business expansion in PM2.5

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 PM10

emissions as a surrogate for PM2.5

emissions in PM2.5 nonattainment areas 

when we adopt the final PM2.5

implementation rules, while three other 

commenters requested continued 

implementation of that 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 authority to do so, States 

must issue NA NSR permits under 

appendix S (as revised for purposes of 

the PM2.5 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 of the effective 

date of this action, the 2005 PM2.5 NSR 

guidance on use of PM10 emissions as a 

surrogate for PM2.5 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 of this 

final action. 

J. Does major NSR apply to PM2.5

precursors during the SIP development 

period? 

As discussed previously in section 

V.A, we have taken final action on NSR 

applicability for PM2.5 precursors. 

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 ‘‘presumed-out’’

precursor. Thus, States 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. In addition, States have the option 

of identifying VOC and/or ammonia as 

precursor(s) by demonstrating that 

emissions of VOC 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 of the effective date 

of this 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 submittal so that 

if a 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 period because 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 of NSR 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 PM2.5 emissions 

can be offset with SO2 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 SO2 should 

be designated as a precursor during the 

interim period, and another suggested 

the same for SO2 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 their 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 or NOX 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 

PM10 surrogate policy to meet the PSD 

requirements for PM2.5. However, for 

delegated PSD States, SO2 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, 

SO2 will be regulated as a precursor in 

all nonattainment areas for PM2.5. 

However, unlike in the proposal, NOX

will not be regulated as a precursor 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 there any Tribal concerns? 

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 ozone and PM2.5 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 the 

playing field for the Tribes and support 

economic development in Tribal areas. 

We also requested comment on ways in 

which States may help provide the 

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 NA NSR rule, 

which refers to appendix S for its 

substantive requirements, and a minor 

NSR rule. In recognition of the concerns 

mentioned above, we have proposed 

and sought comments on options for 

obtaining offset relief in that proposal. 


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We will address these issues in the 

context of that rule. 

L. What are the requirements for minor 

NSR for PM2.5? 

Pursuant to section 110(a)(2)(C) of the 

Act, States must have a minor source 

permitting program. This applies to new 

and 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, 

• SO2, 

• NOX, 

• CO, 

• PM10, and 

• Lead (Pb). 

Based on this action, States must now 

amend their minor source programs to 

include direct PM2.5 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 of classifying 

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. Consequently, no NA 

NSR rules have been developed or 

finalized in this rule. 

VI. Statutory and Executive Order 

Reviews 

A. Executive Order 12866: Regulatory 

Planning and Review 

Under Executive Order (EO) 12866 

(58 FR 51735, October 4, 1993), this 

action is a ‘‘significant regulatory 

action’’ because it is likely to raise novel 

legal or policy issues arising out of legal 

mandates, the President’s priorities, or 

the principles set forth in the Executive 

Order. Accordingly, EPA submitted this 

action to the Office of Management 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 Reduction Act 

The information collection 

requirements in this rule have been 

submitted for approval to the OMB 

under the Paperwork Reduction Act, 44 

U.S.C. 3501 et seq. 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 State or 

local agency (or the EPA Administrator 

in non-delegated States), for example, 

to: (1) Confirm the compliance of status 

of stationary sources, identify any 

stationary sources not subject 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 a continuous basis. 

This final NSR rule does not create 

new information collection 

requirements, but rather expands the 

coverage of the existing requirements of 

the major NSR program. Specifically, 

the rule changes finalized in this action 

add PM2.5 to the list of air 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 of PM2.5 emissions on soils and 

vegetation, as well as on air quality 

related values in Class I areas; 

determining the appropriate best 

available control technology or lowest 

achievable emission rate; and/or 

obtaining offsets. At the same time, 

there would be a reduction in burden 

directly associated with the revocation 

of the annual increment for PM10, which 

is proposed in the proposed rule. 

Over the 3-year period covered by the 

ICR, we estimate an average annual 

burden increase of about 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 

combined increase in burden to average 

about 16,000 hours and $700,000 

annually for all State and local 

reviewing authorities, which is less than 

13 percent. 

Burden means the total time, effort, or 

financial resources expended by persons 

to generate, maintain, retain, or disclose 

or provide 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, processing 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 or otherwise 

disclose the information. 

An agency may not conduct or 

sponsor, and a person is not required 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 a technical 

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 of any 

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 of small entities. Small entities 

include small businesses, small 

organizations, and small governmental 

jurisdictions. 

For purposes of assessing the impacts 

of this 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 or a city, county, town, 


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school district or special district with a 

population of less 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 of this final rule on small 

entities, I certify that this rule will not 

have a significant economic impact on 

a substantial number of small entities. 

The requirements of this final rule apply 

only to new major stationary sources or 

major modifications of existing major 

stationary sources. This final rule does 

not create any new 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, of which act 

as reviewing authorities pursuant to this 

final rule). 

D. Unfunded Mandates Reform Act 

Title II of the 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 of the UMRA, 

we generally must prepare a written 

statement, including a cost-benefit 

analysis, for proposed 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 1 year. Before promulgating 

an EPA rule for which a written 

statement is needed, section 205 of the 

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 of the 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-effective, 

or least-burdensome alternative if the 

Administrator publishes with the final 

rule an explanation of why 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 of the UMRA a small 

government agency plan. The plan must 

provide for notifying potentially 

affected small governments, enabling 

officials of affected small governments 

to have meaningful and timely input in 

the development of our regulatory 

proposals with significant Federal 

intergovernmental mandates, and 

informing, educating, and advising 

small governments on compliance with 

the regulatory requirements. 

We have 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 1 year. 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 PM2.5 to 

the NSR program. However, these 

precursors (SO2, NOX, and VOC) are 

already subject to the existing NSR 

program.) As discussed previously in 

section VI.B on the Paperwork 

Reduction Act, 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 no regulatory requirements that 

might significantly or uniquely affect 

small governments. As noted 

previously, this rule does not create any 

new requirements under the major NSR 

program, but simply expands the 

program to cover an additional pollutant 

(PM2.5). 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 Order 13132—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 

power and responsibilities among the 

various levels of government.’’

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 of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132. Pursuant to the 

terms of Executive 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 of Executive Order 13132, 

however, and consistent with our policy 

to promote communications between us 

and State and local governments, we 

specifically solicited comment on the 

proposed rule from State and local 

officials. 

F. Executive Order 13175—Consultation 

and Coordination With Indian Tribal 

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 their jurisdictions. 

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 PM2.5 NAAQS, but it leaves to the 

discretion of the Tribe the decision of 

whether to develop these programs and 

which programs, or appropriate 

elements of a program, they will adopt. 

Although Executive Order 13175 does 

not apply to this rule, EPA did reach out 

to Tribal leaders and environmental 

staff in developing this rule. 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 if a Tribe were 

implementing such a plan at this time, 

while the rule might have Tribal 

implications with respect to that Tribe, 

it would not impose substantial direct 

costs upon it, nor would it preempt 

Tribal law. 

Furthermore, this rule does not affect 

the relationship or distribution of power 

and responsibilities between the Federal 

government and Indian Tribes. The 

CAA and the TAR establish the 

relationship of the 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 Order 13045—Protection of 

Children From Environmental Health 

and Safety Risks 

Executive Order 13045, entitled 

‘‘Protection of Children 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 to 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 alternatives 

considered 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 of the 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 of the NAAQS. 

H. Executive Order 13211—Actions 

That Significantly Affect Energy Supply, 

Distribution, or Use 

This rule is not a ‘‘significant energy 

action’’ as defined in Executive Order 

13211, ‘‘Actions Concerning Regulations 

That Significantly Affect Energy Supply, 

Distribution, or Use’’ (66 FR 28355 (May 

22, 2001)) because it is not likely to 

have a significant adverse effect on the 

supply, distribution, or use of energy. 

The final rule does not add any new 

requirements to the major NSR program; 

it simply expands the program to cover 

PM2.5 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 of regulated NSR pollutants, we 

believe that any increase in 

expenditures for obtaining NSR permits 

that may result from this rule will be 

marginal rather than significant. 

I. National Technology Transfer and 

Advancement Act 

As noted in the proposed rule, section 

12(d) of the 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 of any VCS. 

J. Executive Order 12898—Federal 

Actions to Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 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 of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of its programs, 

policies, and activities on minorities 

and low-income populations in the 

United States. 

The EPA has determined that this 

final rule will not have 

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 Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. The EPA will 

submit a report containing this rule and 

other required information to the U.S. 

Senate, the U.S. House of 

Representatives, and the Comptroller 

General of the United States prior to 

publication of the rule in the 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 by this action 

will be effective July 15, 2008. 

L. Petitions for Judicial Review 

Under section 307(b)(1) of the Act, 

petitions for judicial review of this 

action must be filed in the United States 

Court of Appeals for the District of 

Columbia Circuit by July 15, 2008. 

Filing a petition for reconsideration by 

the Administrator of this final rule does 

not affect the finality of this rule for the 

purposes of judicial review nor does it 

extend the time within which a petition 

for judicial review may be 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. Determination Under Section 307(d) 

The PSD portions of this rulemaking, 

which implements part C of title I of the 

Act, are subject to the procedural 

requirements in section 307(d) of the 

Act. See section 307(d)(1)(J). In 

addition, pursuant to section 

307(d)(1)(V) of the Act, the 

Administrator determines that the NA 


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NSR portions of this action should also 

be subject to the provisions of section 

307(d) to ensure consistency. All of the 

procedural requirements of section 

307(d), e.g., docketing, hearing, and 

comment periods, have been complied 

with during the course of this 

rulemaking. 

VII. Statutory Authority 

The statutory authority for this action 

is provided by sections 101, 110, 165, 

169, 172, 173, 301, and 302 of the 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) of the Act (42 U.S.C. 7407(d)). 

List of Subjects 

40 CFR Part 51 

Environmental protection, 

Administrative practices and 

procedures, Air pollution control, 

Intergovernmental relations. 

40 CFR Part 52 

Environmental protection, 

Administrative practices and 

procedures, Air pollution control, 

Intergovernmental relations. 

Dated: May 8, 2008. 

Stephen L. Johnson, 

Administrator. 

■ For the reasons stated in the preamble, 

title 40, chapter I of the Code of Federal 

Regulations is amended as follows. 

PART 51—[AMENDED] 

■ 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 is amended 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); 

■ c. By revising paragraph 

(a)(1)(xxxvii)(C); 

■ d. By adding paragraph 

(a)(1)(xxxvii)(D); 

■ e. By redesignating paragraphs (a)(9)(i) 

through (iii) as paragraphs (a)(9)(ii) 

through (iv), respectively, and adding 

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

■ f. 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 

■ g. By adding paragraph (a)(11). 

§ 51.165 Permit requirements. 

(a) * * * 

(1) * * * 

(x)(A) Significant means, in reference 

to a net emissions increase or the 

potential of a source to emit any of the 

following pollutants, a rate of emissions 

that would equal or exceed any of the 

following rates: 

Pollutant Emission Rate 

Carbon monoxide: 100 tons per year 

(tpy) 

Nitrogen oxides: 40 tpy 

Sulfur dioxide: 40 tpy 

Ozone: 40 tpy of volatile organic 

compounds or nitrogen oxides 

Lead: 0.6 tpy 

PM10: 15 tpy 

PM2.5: 10 tpy of direct PM2.5 emissions; 

40 tpy of sulfur dioxide emissions; 40 

tpy of nitrogen oxide emissions unless 

demonstrated not to be a PM2.5

precursor under paragraph 

(a)(1)(xxxvii) of this section 

* * * * * 

(xxxvii) * * * 

(C) Any pollutant that is identified 

under this paragraph (a)(1)(xxxvii)(C) as 

a constituent or precursor of a general 

pollutant listed under paragraph 

(a)(1)(xxxvii)(A) or (B) of this section, 

provided that such constituent or 

precursor pollutant may only be 

regulated under NSR as part of 

regulation of the general pollutant. 

Precursors identified by the 

Administrator for purposes of NSR are 

the following: 

(1) Volatile organic compounds and 

nitrogen oxides are precursors to ozone 

in all ozone nonattainment areas. 

(2) Sulfur dioxide is a precursor to 

PM2.5 in all PM2.5 nonattainment areas. 

(3) Nitrogen oxides are presumed to 

be precursors to PM2.5 in all PM2.5

nonattainment 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 

ambient PM2.5 concentrations. 

(4) Volatile organic compounds and 

ammonia are presumed not to be 

precursors to PM2.5 in any PM2.5

nonattainment area, unless the State 

demonstrates to the Administrator’s 

satisfaction or EPA demonstrates that 

emissions of volatile 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 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 PM2.5 and 

PM10 in nonattainment major NSR 

permits. Compliance with emissions 

limitations for PM2.5 and PM10 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 not be 

considered in violation of this 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 of paragraph (a)(3) of this 

section, 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 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 of paragraph (a)(3) of this 

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) of this 

section for direct PM2.5 emissions or 

emissions of precursors of PM2.5 to 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 

for a particular nonattainment area. 

* * * * * 

■ 3. Section 51.166 is amended as 

follows: 

■ a. By revising paragraphs (b)(23)(i) 

and (b)(49)(i); 

■ b. By removing the word ‘‘or’’ at the 

end of paragraph (b)(49)(iii); 

■ c. By adding and reserving paragraph 

(b)(49)(v); 

■ d. By adding paragraph (b)(49)(vi); 

and 

■ e. By revising paragraphs (i)(5)(ii) and 

(i)(5)(iii). 


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§ 51.166 Prevention of significant 

deterioration of air quality. 

* * * * * 

(b) * * * 

(23)(i) Significant means, in reference 

to a net emissions increase or the 

potential of a source to emit any of the 

following pollutants, a rate of emissions 

that would equal or exceed any of the 

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 of PM10

emissions 

PM2.5: 10 tpy of direct PM2.5 emissions; 

40 tpy of sulfur dioxide emissions; 40 

tpy of nitrogen oxide emissions unless 

demonstrated not to be a PM2.5

precursor under paragraph (b)(49) of 

this section 

Ozone: 40 tpy of volatile 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 (including 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 × 10–¥6

megagrams per year (3.5 × 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 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 of NSR 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 oxides 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 ambient PM2.5 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 or EPA 

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 PM10 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 and PM10 in PSD permits. 

Compliance with emissions limitations 

for PM, PM2.5 and PM10 issued 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 not be considered 

in violation of this section unless the 

applicable implementation plan 

required condensable particular matter 

to be included. 

* * * * * 

(i) * * * 

(5) * * * 

(ii) The concentrations of the 

pollutant in the area that the source or 

modification would affect are less than 

the concentrations listed in paragraph 

(i)(5)(i) of this section; or 

(iii) The pollutant is not listed in 

paragraph (i)(5)(i) of this section. 

* * * * * 

■ 4. Appendix S to Part 51 is amended 

as follows: 

■ a. By revising paragraphs II.A.10(i) 

and II.A.31; 

■ b. By revising paragraph IV.A, 

Condition 3; 

■ c. 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; 

■ d. 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 

■ e. By adding paragraph IV.G.5. 

Appendix S to Part 51—Emission Offset 

Interpretative Ruling 

* * * * * 

II. * * * 

A. * * * 

10. (i) Significant means, in reference to a 

net emissions increase or the potential of a 

source to emit any of the following 

pollutants, a rate of emissions that would 

equal or exceed any of the following rates: 

Pollutant and Emissions Rate 

Carbon monoxide: 100 tons per year (tpy) 

Nitrogen oxides: 40 tpy 

Sulfur dioxide: 40 tpy 

Ozone: 40 tpy of volatile organic compounds 

or nitrogen oxides 

Lead: 0.6 tpy 

Particulate matter: 25 tpy of particulate 

matter emissions 

PM10: 15 tpy 

PM2.5: 10 tpy of direct PM2.5 emissions; 40 

tpy of sulfur dioxide emissions 

* * * * * 

31. Regulated NSR pollutant, for purposes 

of this Ruling, 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 of a general pollutant listed under 

paragraph II.A.31(i) or (ii) of this Ruling, 

provided that such constituent or precursor 

pollutant may only be regulated under NSR 

as part of regulation of the general pollutant. 

Precursors identified by the Administrator 

for purposes of NSR 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 PM2.5 nonattainment areas; or 

(iv) Particulate matter (PM) emissions, 

PM2.5 emissions and PM10 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 and PM10 in permits issued under this 

ruling. Compliance with emissions 

limitations for PM, PM2.5 and PM10 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 not be 


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considered in violation of this section unless 

the applicable implementation plan required 

condensable particulate matter to be 

included. 

* * * * * 

IV. * * * 

A. * * * 

Condition 3. Emission reductions (offsets) 

from existing sources 5 in the area of the 

proposed source (whether or not under the 

same ownership) are required such that there 

will be reasonable progress toward 

attainment of the applicable NAAQS.6 Except 

as provided in paragraph IV.G.5 of this 

Ruling (addressing PM2.5 and its precursors), 

only intrapollutant emission offsets will be 

acceptable (e.g., hydrocarbon increases may 

not be offset against SO2 reductions). 5Subject to the provisions of paragraph 

IV.C of this Ruling. 6The discussion in this paragraph is a 

proposal, but represents EPA’s interim policy 

until final rulemaking is completed. 

* * * * * 

G. Offset ratios. 

1. In meeting the emissions offset 

requirements of paragraph IV.A, Condition 3 

of this 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 area in paragraphs 

IV.G.2 through IV.G.4. 

* * * * * 

5. Interpollutant offsetting. In meeting the 

emissions offset requirements of paragraph 

IV.A, Condition 3 of this Ruling, the 

emissions offsets obtained shall be for the 

same regulated NSR pollutant unless 

interpollutant offsetting is permitted for a 

particular pollutant as specified in this 

paragraph IV.G.5. The offset requirements of 

paragraph IV.A, Condition 3 of this Ruling 

for direct PM2.5 emissions or emissions of 

precursors of PM2.5 may be satisfied by 

offsetting reductions of direct PM2.5

emissions or emissions of any PM2.5

precursor identified under paragraph II.A.31 

(iii) of this Ruling if such offsets comply with 

an interprecursor trading hierarchy and ratio 

approved by the Administrator. 

* * * * * 

PART 52—[AMENDED] 

■ 5. The authority citation for part 52 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart A—[Amended] 

■ 6. Section 52.21 is amended as 

follows: 

■ a. By revising paragraphs (b)(23)(i) 

and (b)(50)(i); 

■ b. By removing the word ‘‘or’’ at the 

end of paragraph (b)(50)(iii); 

■ c. By adding and reserving paragraph 

(b)(50)(v); 

■ d. By adding paragraphs (b)(50)(vi) 

and (i)(1)(xi); 

■ e. By revising paragraph (i)(5)(ii); and 

■ f. By adding paragraph (i)(5)(iii). 

§ 52.21 Prevention of significant 

deterioration of air quality. 

* * * * * 

(b) * * * 

(23)(i) Significant means, in reference 

to a net emissions increase or the 

potential of a source to emit any of the 

following pollutants, a rate of emissions 

that would equal or exceed any of the 

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 

PM10: 15 tpy 

PM2.5: 10 tpy of direct PM2.5 emissions; 

40 tpy of sulfur dioxide emissions; 40 

tpy of nitrogen oxide emissions unless 

demonstrated not to be a PM2.5

precursor under paragraph (b)(50) of 

this section 

Ozone: 40 tpy of volatile 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 (including 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 × 10 6

megagrams per year (3.5 × 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 sulfur 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 of NSR 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 oxides 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 ambient PM2.5 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 or EPA 

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 PM10 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 and PM10 in PSD permits. 

Compliance with emissions limitations 

for PM, PM2.5 and PM10 issued 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 not be considered 

in violation of this 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 PM10 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 

PM2.5’’ (October 23, 1997). Instead, the 

requirements of paragraphs (j) through 


sroberts on PROD1PC70 with RULES
28350 Federal Register / Vol. 73, No. 96 / Friday, May 16, 2008 / Rules and Regulations 

(r) of this section, as interpreted in the 

aforementioned memorandum, that 

were in effect before July 15, 2008 shall 

apply to such source or modification. 

* * * * * 

(5) * * * 

(ii) The concentrations of the 

pollutant in the area that the source or 

modification would affect are less than 

the concentrations listed in paragraph 

(i)(5)(i) of this section; or 

(iii) The pollutant is not listed in 

paragraph (i)(5)(i) of this section. 

* * * * * 

[FR Doc. 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 or to show evidence of being 

already in effect in order to qualify or 

remain qualified for participation in the 

National Flood Insurance Program 

(NFIP). 

DATES: The date of issuance of the Flood 

Insurance Rate Map (FIRM) showing 

BFEs and modified BFEs for each 

community. This date may be 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 for inspection 

at the office of the Chief Executive 

Officer of each 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 community listed. These modified 

elevations have been published in 

newspapers of local circulation and 

ninety (90) days have elapsed since that 

publication. The Assistant 

Administrator of the Mitigation 

Directorate has resolved any appeals 

resulting from this notification. 

This final rule is issued in accordance 

with section 110 of the 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 of real 

property are encouraged to review the 

proof Flood 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 Environmental Policy Act. 

This final rule is categorically excluded 

from the requirements of 44 CFR part 

10, Environmental Consideration. An 

environmental impact assessment has 

not been prepared. 

Regulatory Flexibility Act. As flood 

elevation determinations are not within 

the scope of the Regulatory Flexibility 

Act, 5 U.S.C. 601–612, a regulatory 

flexibility analysis is not required. 

Regulatory Classification. This final 

rule is not a significant regulatory action 

under the criteria of section 3(f) of 

Executive Order 12866 of September 30, 

1993, Regulatory Planning and Review, 

58 FR 51735. 

Executive Order 13132, Federalism. 

This final rule involves no policies that 

have federalism implications under 

Executive Order 13132. 

Executive Order 12988, Civil Justice 

Reform. This final rule meets the 

applicable standards of Executive Order 

12988. 

List of Subjects in 44 CFR Part 67 

Administrative practice and 

procedure, Flood insurance, Reporting 

and recordkeeping requirements. 

■ Accordingly, 44 CFR part 67 is 

amended as follows: 

PART 67—[AMENDED] 

■ 1. The authority citation for part 67 

continues to read as follows: 

Authority: 42 U.S.C. 4001 et seq.; 

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] 

■ 2. The tables published under the 

authority of § 67.11 are amended as 

follows: 

Flooding source(s) Location of referenced elevation 

* Elevation in feet 

(NGVD) 

+ Elevation in feet 

(NAVD) 

# Depth in feet 

above ground 

Modified 

Communities 

affected 

Randolph County, Illinois, and Incorporated Areas 

Docket No.: FEMA–B–7740 

Kaskaskia River ..................... At confluence with Mississippi River ..................................... +392 Village of Evansville, Unincorporated Areas of Randolph 

County. 

Randolph/Monroe County boundary (approximately 700 

feet upstream Anna Lane extended).

+392 

Mississippi River .................... Jackson/Randolph County boundary (approximately Cora 

Road extended).

+382 City of Chester, Unincorporated Areas of Randolph 

County, Village of 

Kaskaskia, Village of Prairie Du Rocher, Village of 

Rockwood. 


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