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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103

DATE: May 25, 2010

SUBJECT: Technical Support Document (TSD) 

EPA-R03-OAR-2010-0386; Notice of Proposed Rulemaking – Revision to 

Emission Limitations for R. Paul Smith Power Station

FROM: Marilyn Powers, Environmental Engineer /s/

Office of Air Program Planning 

TO: File

THRU: Cristina Fernandez, /s/

Associate Director, Office of Air Program Planning 

A. BACKGROUND

On September 4, 2008 (73 FR 51599), EPA approved COMAR regulation 26.11.27 –

Emission Limitations for Power Plants into Maryland’s State Implementation Plan (SIP). This 

regulation, adopted to implement the statutory requirements of Maryland’s Healthy Air Act1

(HAA), established emission limits for annual nitrogen oxides (NOx), ozone season NOx, and 

annual sulfur dioxides (SO2) for the 15 largest electric generating units (EGU) in the State

located at seven power plants, including units 3 and 4 at R. Paul Smith Power Station in 

Washington County, Maryland.

Maryland’s HAA has an exception that allows R. Paul Smith units 3 and 4 to operate 

without complying with the emission reduction requirements set forth in the HAA if PJM 

Interconnection Inc. (PJM) determines that the termination of operation of the facility will 

adversely affect the reliability of electrical service in the PJM region. Subsequent to Maryland’s 

adoption of COMAR 26.11.27 and EPA’s approval of the rule into the Maryland SIP, PJM 

determined that the R. Paul Smith facility is needed to maintain electricity reliability in the State. 

The HAA requires that if R. Paul Smith units 3 and 4 are allowed to operate without complying 

with the emissions limitations established in the statute, certain conditions must be met. These 

conditions require that the facility not operate at emissions levels greater than the highest level 

measured at the facility during the calendar years from 2000 through 2004, and that the Maryland 

 

1 Annotated Code of Maryland Environment Title 2 Ambient Air Quality Control Subtitle 10 Health Air Act Sections 

2-1001 - 2-1005.
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Department of the Environment (MDE) must review the operations of the facility, then adopt 

regulations to establish an alternative emissions requirement for the facility. In accordance with 

these statutory requirements, MDE revised COMAR 26.11.27 to establish alternate emission 

limits for these two EGUs at R. Paul Smith. 

On November 20, 2009 (74 FR 60199), EPA determined that the MartinsburgHagerstown area had attained the 1997 PM2.5 standard on the basis of monitored air quality data 

from the three year period from 2006 through 2008. 

B. EPA REQUIREMENTS

Section 110(l) of the Clean Air Act (CAA) dictates that the EPA Administrator shall not 

approve a revision of a plan if the revision would interfere with any applicable requirement 

concerning attainment and reasonable further progress (RFP) or any other applicable requirement 

of section 110. 

Maryland submitted COMAR 26.11.27 to EPA as one of the measures it is relying on to 

attain the 1997 8-hour ozone and PM2.5 NAAQS in nonattainment areas throughout the State. 

Washington County is part of the Hagerstown-Martinsburg, MD-WV metropolitan statistical 

area, which is in attainment of the 1997 8-hour ozone standard but was designated as 

nonattainment for the 1997 PM2.5 standard. Washington County’s attainment of the 8-hour 

ozone standard is based on an Early Action Compact (EAC), approved on August 17, 2005 (70 

FR 48283), that included an action plan to assure the area continues to attain the standard 

through 2012. Washington County is also now attaining the PM2.5 standard, and has submitted a

PM2.5 Attainment Plan for EPA’s approval. For EPA to approve this SIP revision for R. Paul 

Smith, Maryland is required to demonstrate that the revised emission limits do not impact either 

of these plans or any other programs under section 110.

C. STATE’S SUBMITTAL:

On December 15, 2009, the MDE submitted a revision to the Maryland SIP (Maryland 

revision #09-04) pertaining to the establishment of revised NOx and SO2 emission limits for the 

EGUs located at R. Paul Smith. These revised limits are set forth in Regulations .02 and .03 

under COMAR 26.11.27. The submittal includes documentation that the revisions were properly

adopted via the State’s administrative procedures, including public notice and opportunity for a 

public hearing. The only comments submitted were from EPA Region 3. On January 27, 2010, 

EPA determined that the submittal was administratively and technically complete.

The changes to COMAR 26.11.27 involve the removal of the existing R. Paul Smith caps 

from the statewide total cap and the addition of new sections that set forth the higher caps, as 

follows:
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- A new section C was added to Regulation .02 – Applicability and Exemptions, which 

stipulates that the R. Paul Smith facility is subject to the NOx and SO2 emissions in 

revised sections B(8) and C(3) of Regulation .03 – General Requirements.

- Section B(8) changes the NOx annual tonnage limits for R. Paul Smith from 416 tons to 

1390 tons starting with the January 1, 2009 through December 31, 2009 control period, 

and the NOx ozone season tonnage limit from 140 tons to 545 tons starting with the 2009 

ozone season. 

- Section C(3) changes the SO2 annual tonnage from 1002 tons to 4590 tons starting with 

the January 1, 2010 through December 31, 2010 control period.

It is noted that COMAR 26.11.27 also includes revisions to section D of Regulation .03. 

Maryland’s December 15, 2009 letter expressly submitted only the NOx and SO2 limits in 

sections B and C as a SIP revision. As section D has not previously been approved as part of the 

Maryland SIP, the revisions to Section D are excluded from this action.

D. EVALUATION OF STATE SUBMITTAL:

As noted previously, Maryland is relying on COMAR 26.11.27 as one of the measures to 

help it attain the PM2.5 NAAQS in the Washington County nonattainment area. Section 110(l) 

requires that the revision not interfere with any applicable requirement pertaining to attainment 

for this area.

In response to an EPA comment regarding the section 110(l) requirements, Maryland 

submitted a demonstration to show that the increase in caps for NOx ozone season, NOx annual 

and SO2 annual emissions at R. Paul Smith do not impede Washington County’s attainment of 

the 1997 NAAQS. The demonstration is based on air monitoring data, emissions analysis, and 

information from the attainment modeling that was done by MANE-VU for this area.

For 8-hour ozone, the State maintains that Washington County’s attainment of the 1997 

8-hour ozone standard is not affected by the emission limit changes for R. Paul Smith contained 

in this SIP revision. The EAC for 8-hour ozone showed attainment starting in 2007, with an 

Early Action Plan (EAP) to assure maintenance of the standard through 2012. Because the EAC 

program pre-dated the adoption of the HAA regulation, the emission limits originally required by

COMAR 26.11.27 for R. Paul Smith were not reflected in the emission reductions relied upon 

for the EAC, and are not relied upon for maintenance through 2012. A review of the EAC and 

EAP showed that the projection of maintenance for the five-year period from 2007 – 2012 does 

not include the HAA as either a control measure or a contingency measure that is relied upon or 

this facility.
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Likewise, for PM2.5, Maryland asserts that Washington County’s attainment of the 1997 

PM2.5 standard is not affected by this SIP revision. The State notes that Washington County has 

been attaining the 1997 annual and 24-hour standard since 2000, and has continued to meet the 

standard through 2008. As part of its section 110(l) demonstration, Maryland included data from 

the Washington County attainment plan2 which shows annual PM2.5 design values of 14.8 

micrograms per cubic meter (μg/m3) for the 2000 – 2002 period, with design values equal to or 

less than 14.1 μg/m3in the intervening years up to 2008. Maryland also provided information 

from the MANE-VU modeling which shows R. Paul Smith emissions in 2009 as 1335 tons of 

NOx and 5426.8 tons of SO2.. On this basis, the State asserts that the total NOx and SO2

emissions projected for 2009, 6761.8 tons, is actually 11 percent higher than the total NOx and 

SO2 emissions that would be allowed for R. Paul Smith by this SIP revision, 5,980 tons. Table 1 

shows this comparison.

Table 1. Comparison of emission caps to modeled values

Plant ID Plant Name 2009 Projected 

Emissions

Revised Caps – this SIP 

revision

043-0005 Allegany Energy

Supply LLC – R. 

Paul Smith

NOx SO2 NOx SO2

1335 5426.80 1390 4590

As shown in Table 1, the revised NOx limit for this facility, 1,390 tons, is actually higher 

than the 2009 model year NOx emission value, 1,335 tons, by 55 tons. However, the SO2 limit 

for this facility, 4590 tons, is lower than the 2009 model year emissions, 5426.80 tons, by 836.8 

tons. EPA looked to the Washington County PM2.5 attainment plan submitted by Maryland to 

evaluate this situation. In order to address the contingency measures required to be included in 

the attainment plan, Maryland evaluated the equivalency of reductions for precursors of PM2.5 to 

see if the excess SO2 reductions were adequate to offset the insufficient number of NOx 

reductions. The evaluation of relative impacts of reductions of NOx and SO2 for this area was 

based on the modeling that was performed. Section 10.1.2 of the attainment plan explains how 

the relative reduction factor was derived:

“The recommended approach is to review existing data and sensitivity studies performed 

as part of photochemical modeling to estimate the relative impact of reductions in 

different precursors on PM concentrations. Basing an equivalency ratio on relative 

reduction factors as generated by the Community Multiscale Air Quality (CMAQ) 

modeling results in a ratio of 1.1 to 1.4 tons of NOx for each ton of SO2 . . . . Using 

sensitivity analyses created by Visibility Improvement of State and Tribal Association of 

the Southeast (VISTAS) and Georgia Tech . . ., equivalency ratios range from 3.3 to 3.6 

tons of NOx for each ton of SO2.”

A relative reduction factor ranging from 1.1 to 3.6 tons of NOx for each ton of SO2 is adequate to 

 

2 Washington County, MD PM2.5 State Implementation Plan and Base Year Inventory, February 29, 2008.
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of offset the higher NOx value. At the most conservative ratio of 1.1, 55 tons of NOx is 

equivalent to 50 tons of SO2.

A further look at the air quality data for Washington County for 2009 is useful to inform 

this section 110(l) analysis, particularly as the revised caps for R. Paul Smith became effective 

beginning in 2009. Although not yet certified or quality-assured, monitored 2009 ambient air 

quality concentration data for both 8-hour ozone and PM2.5 for the Hagerstown – Martinsburg,

MD-WV area continues to show attainment of both standards, as can be seen in Table 2 and 3

below. The data shown in these tables is from the EPA Air Quality System (AQS), and the raw 

data reports, from which the tabular data is derived, are included in the docket for this action. 

Table 2. 2009 Monitored Values for Annual PM2.5, in μg/m3

Site ID City County State

First 

Quarter

2009

Second 

Quarter 

2009

Third 

Quarter 

2009

Fourth 

Quarter 

2009

240430009 Hagerstown Washington Co MD 10.79 9.62 10.64 7.35

540030003 Martinsburg Berkeley Co WV 14.02 11.35 12.47 10.38

Table 3. 2009 Monitored Values for 8-hour Ozone, in ppb

Site ID City County State

4

th highest 

value in 

2009 

Highest 

value in 

2009

240430009 Hagerstown Washington Co MD 65 70

540030003 Martinsburg Berkeley Co WV 65 70

Finally, one other factor to consider is that Maryland’s Clean Air Interstate Rule (CAIR) 

is in effect throughout the State, and applies to units 3 and 4 at the R. Paul Smith facility. 

Maryland’s CAIR SIP revision was approved on October 30, 2009 (74 FR 56117). Under the 

CAIR program, R. Paul Smith is allocated 191 tons of NOx allowances for the ozone season 

trading program, 454 tons of NOx allowances for the annual trading program, and 175 

allowances for annual SO2. These CAIR ozone season and annual allocations are less than the

limits imposed in this SIP revision, however, regardless of any emission limits established by the 

State for these units, R. Paul Smith must comply with the NOx and SO2 allowance holding 

requirements of CAIR – i.e. emissions that exceed its allocations would need to be covered on a 

one-to-one basis by obtaining additional allowances from the CAIR allowance market. This SIP 

revision therefore does not impact the CAIR trading program. 
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F. CONCLUSIONS AND RECOMMENDED AGENCY ACTION

EPA’s analysis of the impacts of this SIP revision concludes that it does not negatively

affect the attainment requirements for either the PM2.5 or 8-hour ozone standards. It is 

recommended that a notice of proposed rulemaking be prepared approving the SIP revision.