2010 SO 2 NAAQS (75 F ed. R eg. 35520 )
District of Columbia Infrastructure SIP

June 2014

A TTACHMENT B

Section 110(a)(2)(D)(i) : Interstate Transport Provisions, Part I Include an explanation in support of the conclusion that no source will contribute significantly to nonattainment or interfere with maintenance of the SO2 NAAQS in another state.

The District of Columbia (District) has recommended an unclassifiable desi gnation for the 2010 sulfur dioxide (SO 2 ) national ambient air quality standards (NAAQS). This is at least in part because n o source in the Distr ict contribute s significantly to nonattainment or interfere s with maintenance of the

2010 SO 2 NAAQS in another state. N o source has caused a violation of the 2010 SO 2 NAAQS and no source emits quantities that are potentially of concern.

No SO 2 NAAQS Violations

To date, the District operates two ambient air monitors to measure SO 2 : one long

- term monitor at the
River Terrace site , and one new trace

- SO 2 monitor at the McMillan NCore site that was deployed in

2011 . The River Terrace monitor has never shown a violation of any SO 2 standard, as demonstrated in Figure 1.

Figure 1 . Monitored SO 2 Concentrations in the District Over TimeInsignificant Contribution

In the SO 2 NAAQS final rule (75 Fed. Reg. 35520)

, the U.S. Environmental Protection Agency ( EPA )
ruled that it would be reasonable to expect states to demonstrate, at a minimum, that major SO 2 sources (≥ 100 tpy) are not causing or contributing to violations of the 1

- hour SO 2 NAAQS.”

A letter to the District Department of the Environment (DDOE) Director on April 12, 2012, from EPA suggested that

, “EPA’s discussions with stakeholders about ho w best to implement the NAAQS may result in changes to our previously described recommendations for implementing the SO 2 standard in unclassifiable areas.” EPA recommended focusing on “the traditional infrastructure elements of Clean Air Act sections 110(a)(1) and (2), rather than on modeling demonstrations showing future attainment of the standard by a fixed date,” as ini tially required in the final SO 2 NAAQS rule and further described in the draft implementation guidance

.

EPA’s 2013 document 1 suggested a potential revision to the emissions threshold to 2000 to 3000 tons per year (tpy) for sources in densely populated area s that are part of a core

- based statistical area (CBSA) of more than one million people.

In the District, t here is only one source that has emitted relatively large amounts of SO 2 : the U.S. Capitol Power Plant (CPP)

. Total emissions of SO 2 from the facili ty hav e been well below even half of EPA’s potential threshold, or less than 1000 tons per year, since 2002. H istorically, t wo of the large boilers at

t he facility have burned coal , which contains sulfur, as a fuel source. In recent years, the use of coal at CPP has dropped dramatically. Figure 2 demonstrates that the reduced use of coal has resulted in a similar drop in SO 2 emissions in recent years.

Figure 2. Capitol Power’s Coal Use and SO 2 Emissions

Emissions of SO 2 from CPP are expected to remain low because of recent ly finalized air quality permit
actions

. On June 6, 2013, DDOE issued final permits that established facility

- wide emission limits at
CPP . The permits also allow for the installation of a highly efficient natural gas

- fired cogeneration

1 U.S. EPA, “Next Steps for Area Designations and Implementation of the Sulfur Dioxide National Ambient Air Quality Standard” (February 6, 2013), found at: http://www.epa.gov/airquality/sulfurdioxide/pdfs/20130207SO2StrategyPaper.pdf

.system at the facility that will reduce its reliance on coal

- burning units. The facility’s potential to emit

SO 2 is less than 3,900 tons per year, even with a cogeneration system f ully constructed 2

. After the cogeneration plant is commissioned and operational, the facility is required to cease burning coal except
in very infrequent force majeure situations

. 3

There are only two other major source facilities in the District that t ypically emit more than one ton of

SO 2 per year : Pepco

- Benning Road Generation Station and U.S. General Services Administration. The following chart shows SO 2 emissions for each facility in recent years , primarily due to the usage of oil:

Figure 3. SO 2 Emissions (tpy) from Other Facilities in the District

Facility 2008 2009 2010 2011 2012 Pepco

- Benning 278.1 106.9 871.7 510.8 21

U.S. GSA 3 1.6 1.5 1.4 15.7

Pepco

- Benning’s two electric generating units (EGUs) that emitted a majority of the facility’s SO 2 emissions shut down in 2012. The closure was a permit condition submitted as part of a S tate
I mplementation P lan (SIP) revision to address the Clean Air Act’s requirements for Regional Haze, which was approved by EPA on February 2, 2012 (77 Fed. Reg. 5191).

SO 2 emissions at GSA are not expected to substantially increase in the future, especially with the District’s new source review program (20 DCMR Chapter 2) and preventio n of significant deterioration federal implementation plan (PSD FIP), which both control emissions due to facility changes. There is a plant

- wide emission limit for SO 2 in GSA’s Title V permit of 17 tons per year.

Additional SO 2 controls in the District ’s SIP include sulfur content limits on fuel oil (20 DCMR § 801), a high enhanced inspection and maintenance (I/M) program (see 40 C.F.R. § 52.470(c)), and numerous
Federal PM 2.5 measures.

No Interference with Maintenance (Prong 2)

There are no nonattainment areas for S O 2 within a 50

- kilometer radius of the District, which is the standard distance generally considered by EPA for air dispersion modeling (Appendix W to 40 C.F.R. Part 51). The most recent design values (DVs) computed using quality

- assured and certified ambient air modeling data, based on the Federal Reference Method or an equivalent monitoring measurement, and reported to EPA’s Air Quality System (AQS) in states bordering the District are in Figure 4:

Figure 3. Recent 1

- Hour NAAQS Design Values at Monitors in Maryland and Virginia ( in parts per billion)

State County Site ID 2008

- 2010 2009

- 2011 2010

- 2012 Maryland Garrett County 24

- 023

- 0002 41 31 19 Maryland Prince George's County 24

- 033

- 0030 21 15 11

2 The Capitol Power Plant does not have a plant

- wide emission limit for SO2. According to their 2009 Title V permit applicatio n, their potential to emit SO2 was 3875.1 tpy. Construction of the cogeneration project would add 8.4 tpy.

3 DDOE, “District Issues Air Quality Permits for Cogeneration Equipment at the U.S. Capitol Power Plant” (June 6, 2013),

found at: http://ddoe.dc.gov/release/district

- issues

- air

- quality

- permits

- cogeneration

- equipment

- us

- capitol

- power

- plant

.State County Site ID 2008

- 2010 2009

- 2011 2010

- 2012 Virginia Charles City County 51

- 036

- 0002 50 43 34 Virginia Richmond city 51

- 760

- 0024 39 35 25 Virginia Roanoke County 51

- 161

- 1004 11 10 8 Virginia Rockingham County 51

- 165

- 0003 11 9 6 Source: “Design Values” on EPA website at: http://www.epa.gov/airtrends/values.html ; only complete and valid data

All nearby DVs are well below the 2010 1

- hour NAAQS for SO 2 of 75 ppb. Since there are also no nearby areas violating the S O 2 NAAQS, the District has no reason to believe that any monitors identified in the table above may have difficulty maintaining the S O 2 standards, particularly as a result
of emissions from the District.

Conclusion

Since the District’s largest source s of SO 2 emissions emit far less than EPA’s initial ly proposed
threshold for study of 100 tpy , there is no reason to believe that any source in the District will contribute significantly to nonattainment or interfere with maintenance of the SO 2 NAAQS in another st ate.

Currently, t he District is not aware of any plans to establish a source that emits substantial amounts of

SO 2 within its borders. Thus, it is reasonable to conclude that no source will contribute significantly to
nonattainment or interfere with maintenance of the NAAQS in another state.