UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION III 

SUBJECT: 

FROM: 

TO: 

1650 Arch Street 

Philadelphia, Pennsylvania 19103-2029 

D).-0{.--L.oiS 

David pbell sociate Director 

Office of Permits and Air T oxics 

Approval and Promulgation of Air Quality Implementation 

Plans; Maryland; Preconstruction Requirements-Nonattainment 

New Source Review (NSR) 

I. BACKGROUND 

The Maryland Department of the Environment (MDE) has submitted a State Implementation 

Plan (SIP) revision request, pertaining to the New Source Review (NSR) requirements of the 

Clean Air Act (CAA). The proposed revision affects Maryland's nonattainment New Source 

Review (NSR) program. If approved, this action would revise the previously approved version 

of their rules as described below. 

II. SUMMARY OF ACTIONS 

On August 22, 2013, MDE submitted a SIP revision request to EPA. This SIP revision request, 

if approved, would revise Maryland's currently approved nonattainment NSR program by 

amending Regulation .01 under section 26.11.01 of the Code of Maryland Regulations 

(COMAR), and Regulations .01 and .02 under COMAR 26.11.17. Generally, the revisions 

incorporate provisions related to the 2008 "Implementation of the New Source Review (NSR) 

Program for Particulate Matter Less than 2.5 Micrometers (PM2.s)" (2008 NSR PM2.s Rule; 73 

FR 28321). For reasons outlined below, EPA is proposing to approve MDE's August 22,2013 

approval. 

Following is a discussion of the background of EPA's PM2.s regulations, as well as an analysis of 

the specific revisions submitted by MDE. 

III. Background 

B. PM2.s 

Fine particles in the atmosphere are made up of a complex mixture of components. Common 

constituents include sulfate (S04); nitrate (N03); 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.S 

micrometers or less (a micrometer is one-millionth of a meter, and 2.S 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.s. "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 reaetions. 

The health effects associated with exposure to PM2.s include potential aggravation of respiratory 

and cardiovascular disease (i.e., lung disease, decreased lung function asthma attacks and certain 

cardiovascular issues). Epidemiological studies have indicated a cmTelation between elevated 

PM2.s levels and premature mortality. Groups considered especially sensitive to PM2.s exposure 

include older adults, children, and individuals with heart and lung diseases. For more details 

regarding health effects and PM2.s see EPA's Web site at 

http://www.epa.gov/oar/particlepollution/ (see heading "Health and Welfare"). 

On July 18, 1997, EPA revised the NAAQS for PM to add new standards for fine particles, using 

PM2.s as the indicator. Previously, EPA used PMto (inhalable particles smaller than or equal to 

10 micrometers in diameter) as the indicator for the PM NAAQS. EPA established health-based 

(primary) annual and 24-hour standards for PM2.s, setting an annual standard at a level of 1S 

micrograms per cubic meter (J.tg/m3

) and a 24-hour standard at a level of 6S J.tg/m3 (62 FR 

3 86S2). At the time the 1997 primary standards were established, EPA also established welfarebased (secondary) standards identical to the primary standards. The secondary standards are 

designed to protect against major environmental effects ofPM2.s, such as visibility impairment, 

soiling, and materials damage. On October 17, 2006, EPA revised the primary and secondary 

NAAQS for PM2.s. In that rulemaking, EPA reduced the 24-hour NAAQS for PM2.s to 35 J.tg/m3 

and retained the existing annual PM2.s NAAQS of 15 J.tg/m3 (71 FR 61236). 

1. Implementation of NSR Requirements for PM2.s- the NSR PM2.s Rule 

After EPA promulgated the NAAQS for PM2.s on October 23, 1997, the Agency issued a 

guidance document written by John Seitz entitled "Interim Implementation ofNew Source 

Review Requirements for PM2.s" (Seitz Memo). The Seitz Memo was designed to help states 

implement NSR requirements pertaining to the new PM2.s NAAQS in light oftechnical 

difficulties posed by PM2.s at that time. Specifically, the Seitz Memo stated: "PMto may 

properly be used as a surrogate for PM2.s in meeting NSR requirements until these difficulties are 

resolved." 

EPA also issued a guidance document entitled "Implementation ofNew Source Review 

Requirements in PM2.s Nonattainment Areas" (the "200S PM2.s Nonattainment NSR Guidance"), 

on AprilS, 200S, the date that EPA's PM2.s nonattainment area designations became effective for 

the 1997 NAAQS. This memorandum provided guidance on the implementation of the 

nonattainment major NSR provisions in PM2.s nonattainment areas in the interim period between 

the effective date ofthe PM2.s nonattainment area designations (AprilS, 200S) and EPA's 

promulgation of final PM2.s nonattainment NSR regulations. Besides re-affirming the 

continuation of the PM to Surrogate Policy for PM2.s attainment areas set forth in the Seitz Memo, 

the 200S PM2.s nonattainment NSR Guidance recommended that until EPA promulgated the 

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PM2.s major NSR regulations, "States should use a PMw nonattainment major NSR program as a 

surrogate to address the requirements of nonattainment major NSR for the PM2.s NAAQS." 

On May 16,2008, EPA finalized the "Implementation of the New Source Review (NSR) 

Program for Particulate Matter Less than 2.5 Micrometers (PM2.s)" (2008 NSR PM2.s Rule) to 

implement the 1997 PM2.s NAAQS, including changes to the NSR program (See, 73 FR 28321 ). 

The 2008 NSR PM2.s Rule revised the NSR program requirements to establish the framework for 

implementing preconstruction permit review for the PM2.s NAAQS in both attainment and 

nonattainment areas. The 2008 NSR PM2.s Rule required that major stationary sources seeking 

permits must directly satisfy the PM2.s requirements, as of the effective date of the rule, rather 

than relying on PMw as a surrogate, with two exceptions. The first exception was a 

"grandfathering" provision in the Federal PSD program at 40 CFR 52.21(i)(l)(xi). This 

grandfathering provision.applied to sources that had applied for, but had.not yet received, a final 

and effective PSD permit before the July 15, 2008, effective date ofthe May 2008 final rule. 

The second exception was that states with SIP-approved PSD programs could continue to 

implement the Seitz Memo's PM10 Surrogate Policy for up to three years (until May 2011) or 

until the individual revised state PSD programs for PM2.s are approved by EPA, whichever came 

first. For additional information on the NSR PM2.s Rule, see (73 FR 28321). On Febmary 11, 

2010, EPA proposed to repeal the grandfathering provision for PM2.s contained in the federal 

PSD program at 40 CFR 52.21(i)(l)(xi) and to end early the PMw Surrogate Policy applicable in 

states that have a SIP approved PSD program (75 FR 6827). In support of this proposal, EPA 

explained that the PM2.s implementation issues that led to the adoption ofthe PMw Surrogate 

Policy in 1997 have been largely resolved to a degree sufficient for sources and permitting 

authorities to conduct meaningful permit-related PM2.s analyses. The repeal of the 

grandfathering rule was finalized on May 18, 2011 (76 FR 28646). 

The 2008 NSR PM2.s Rule also established the following NSR requirements to implement the 

PM2.s NAAQS: (1) Require NSR permits to address directly emitted PM2.s and precursor 

pollutants; (2) establish significant emission rates for direct PM:u and precursor pollutants 

(including sulfur dioxide (S02) and oxides of nitrogen (NOx)); (3) establish PM2.s emission 

offsets; and (4) require states to account for gases that condense to form particles (condensables) 

in PM2.s emission limits. 

Additionally, the 2008 final rule authorized states to adopt provisions in their nonattainment 

NSR rules that would allow major stationary sources and major modifications locating in areas 

designated nonattainment for PM2.s to offset emissions increases of direct PM2.s emissions or 

PM2.s precursors with reductions of either direct PM2.s emissions or PM2.s precursors in 

accordance with offset ratios contained in the approved SIP for the applicable nonattainment 

area. The inclusion, in whole or in part, of the interpollutant offset provisions for PM2.s is 

discretionary on the part of the states. In the preamble to the 2008 final rule, EPA included 

preferred or presumptive offset ratios, applicable to specific PM2.s precursors that states may 

adopt in conjunction with the new interpollutant offset provisions for PM2.s, and for which the 

state could rely on the EPA's technical work to demonstrate the adequacy ofthe ratios for use in 

any PM2.s nonattainment area. Alternatively, the preamble indicated that states may adopt their 

own ratios, subject to the EPA's approval, that would have to be substantiated by modeling or 

other technical demonstrations of the net air quality benefit for ambient PM2.s concentrations. 

The preferred ratios were subsequently the subject of a petition for reconsideration, which the 

Administrator granted. EPA continues to support the basic policy that sources may offset 

increases in emissions of direct PM2.s or of any PM2.s precursor in a PM2.s nonattainment area 

with actual emissions reductions in direct PM2.s or PM2.s precursors in accordance with offset 

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ratios as approved in the SIP for the applicable nonattainment area. However, we no longer 

consider the preferred ratios set forth in the preamble to the 2008 final rule for PM2.s NSR 

implementation to be presumptively approvable. Instead, any ratio involving P~'b.s precursors 

adopted by the state for use in the interpollutant offset program for PM2.s nonattainment areas 

must be accompanied by a technical demonstration that shows the net air quality benefits of 

such ratio for the PM2.s nonattainment area in which it will be applied. 

The 2008 NSR PM2.s Rule, as well as the 2007 "Final Clean Air Fine Particle Implementation 

Rule" (2007 PM2.s Implementation Rule) 1 were the subject oflitigation before the United States 

Court of Appeals for the D.C. Circuit (the Court) in Natural Resources Defense Council v. EPA.2 

On January 4, 2013, the court remanded to EPA both the 2007 PM2.s Implementation Rule and 

the 2008 NSR PM2.s Rule. The court found that in both rules EPA erred in implementing the 

1997 PM2.s NAAQS solely pursuant to the general implementation provisions of subpart 1 of 

part D of title I of the CAA, rather than pursuant to the additional implementation provisions 

specific to particulate matter in subpru14 of part D of title I.3 As a result, the court remanded 

both rules and instructed EPA "to re-promulgate these rules pursuant to Subpart 4 consistent with 

this opinion." Although the court declined to establish a deadline for EPA's response, EPA 

intends to respond promptly to the court's remand and to promulgate new generally applicable 

implementation regulations for the PM2.s NAAQS in accordance with the requirements of 

subpart 4. In the interim, however, states and EPA still need to proceed with implementation of 

the 1997 PM2.s NAAQS in a timely and effective fashion in order to meet statutory obligations 

under the CAA and to assure the protection of public health intended by those NAAQS. 

IV. Analysis 

PM2.s 

The PM2.s provisions submitted by MDE for approval into the Maryland SIP largely mirror the 

2008 PM2.s NSR Rule, which, as stated above, required NSR permits to address directly emitted 

PM2.s and precursor pollutants, established significant emission rates for direct PM2.s and 

precursor pollutants (including sulfur dioxide (S02) and oxides of nitrogen (NOx)); established 

PM2.s emission offsets, and required states to account for gases that condense to :form particles 

(condensables) in PM2.s emission limits. However, the proposed revisions do not include 

provisions relating to interpollutant offset ratios for PM2.s precursor emissions. 

EPA is in the process of evaluating the requirements of subpart 4 as they pertain to 

nonattainment NSR. In particular, subpart 4 includes section 189( e) of the CAA, which requires 

the control of major stationary sources ofPM10 precursors (and hence under the eourt decision, 

PM2.s precursors) "except where the Administrator determines that such sources do not 

contribute significantly to PM10 levels which exceed the standard in the area." The evaluation of 

1 72 FR 20586 (April25, 2007) 

2 706 F.3d 428 (D.C. Cir. 2013) 

3 The court's opinion did not specifically address the point that implementation under subpart 4 requirements would 

still require consideration of subpart 1 requirements, to the extent that subpart 4 did not override subpart 1. EPA assumes that 

the court presumed that EPA would address this issue of potential overlap between subpart 1 and subpart 4 requirements in 

subsequent actions 

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which precursors need to be controlled to achieve the standard in a particular area is typically 

conducted in the context ofthe state's preparing and the EPA's reviewing of an area's attainment 

plan SIP. At the time of submittal, three areas in Maryland were designated as nonattainment for 

PM2.s: the Maryland portion of DC-MD-VA nonattainment area for the 1997 annual PM2.s 

NAAQS; the Baltimore nonattainment area for the 1997 annual PM2.s NAAQS; and the 

Maryland portion of the Martinsburg-Hagerstown, MD-WV nonattainment area for the 1997 

annual PM2.s NAAQS. 

EPA has taken final action to redesignate all ofthese areas to attainment: on October 6, 2014, 

EPA took final action to redesignate the Metro-Washington area; on December 16,2014, EPA 

took final action to redesignate both the Baltimore nonattainment area and the MartinsburgHagerstown nonattainment area to attainment. See 79 FR 60081, 79 FR 75032 and 79 FR 75035, 

.respectively. As a result, MDE is no longer obligated to submit a nonattainment NSR SIP 

revision under section 189 of the CAA addressing nonattainment NSR permitting requirements 

for PM2.s, including the requirements under subpart 4. Therefore, EPA has not evaluated the 

August 22, 2013 submittal for the purposes of determining compliance with the subpart 4 

requirements. To the extent that any area is designated nonattainment for PM2.s in Maryland in 

the future, MDE will have to make a submission under Section 189(a)(2) of the CAA addressing 

how its nonattainment permitting program satisfies the CAA statutory requirements as to PM2.s, 

including subpart 4 and any applicable PM2.s Federal implementation rules. 

IV. SUMMARY OF CHANGES 

This SIP Revision includes amendments to Regulation .01 under COMAR 26.11.01 

(General Administrative Provisions) and Regulations .01 and .02 under COMAR 26.11.17 

(Nonattainment Provisions for Major New Sources and Major Modifications). 

V. RECOMMENDED AGii:NCY ACTION 

I find that the proposed revisions meet the applicable requirements of the CAA. Accordingly I 

recommend that approval be granted to Maryland's August 22, 2013 submittal. 

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