1 Draft Technical Support Document

Maryland Area Designations for the 2010 SO 2 Primary National Ambient Air Quality Standard

Summary

Pursuant to section 107(d) of the Clean Air Act (CAA), the U.S. Environmental Protection Agency (EPA) must designate areas as either “unclassifiable

, ” “attainment

, ” or “nonattainment”

for the 2010 1

- hour sulfur dioxide (SO 2 ) primary national ambien t air qu ality standard (NAAQS). The CAA defines a nonattainment area as one that does not meet the NAAQS or that contributes to a violation in a nearby area. An attainment area is defined as any area other than a

nonattainm ent area that meets the NAAQS. Unclass ifiable areas are defined as those that cannot be classified on the basis of available information as meeting or not meeting the NAAQS.

Maryland submitted a designation recommendation on Apri l 19, 2011 and updated its designation recommendation with a letter dated November 20, 2015. EPA is now subject to a

court

- ordered July 2, 2016 deadline to designate certain areas established by the U.S. District

Court for the Northern District of California. One area in Anne Aru ndel County, Maryland must
be designated by EPA by thi s deadline, due to its having a SO 2 source with emissions over

certain thresholds identified in the court order. This deadline is the first of three deadlines established by the court for EPA to comple te area designations for the 2010 SO 2 NAAQS

. Table 1 below lists Maryland’s 2015 recommendation for the area around Wagner, Maryland’s 2011 recommendation for Baltimore City, and identifies the portions of count ies in Maryland

that EPA intends to designate by July 2, 2016 based on an assessment and characterization of air quality through ambient air quality data, air dispersion modeling , other evidence and supporting information, or a combination of the above

.

Table 1: Maryland’s Recommend ed and EPA’s Intended Designations

Area Maryland’s

Recommended

Area Definition Maryland’s

Recommended Designation EPA’s Intended

Area Definition EPA’s Intended

Designation

Anne Arundel County and

Baltimore County Area boundary

not provided Attainment P ortions of

Anne Arundel and

Baltimore Counties

that are within 35.5

kilometers of Herbert Wagner’s
Unit 3 stack, which

is located at 39.17765N latitude,

76.52752W longitude Nonattainment2

Baltimore City Baltimore City Unclassifiable Same as State’s

Recommendation Unclassifiable/Attainment

Background

On June 3, 2010, EPA revised the primary (health

- based) SO 2 NAAQS by establishing a new

1

- hour standard at a level of 75 parts per billion (ppb) which is attained when the 3

- year average of the 99th percentile of 1

- hour daily maximum concentrations does not exceed 75 ppb. This NAAQS was published in the Federal Register on June 22, 2010 (75 FR 35520) and is codified

at 40 CFR 50.17

. EPA determined this is the level necessary to protect public health with an adequate margin of safety, especially for children, the elderly and those with asthma. These groups are particularly susceptible to the health effects associated with breathing SO 2

. T he two prior primary standar ds of 140 ppb evaluated over 24 hours, and 30 ppb evaluated over an entire

year, codified at 40 CFR 50.4, remain applicable

. 1 However

, EPA is not currently designating areas on the basis of either of these two primary standards. Similarly, the secondary standard for

SO 2

, set at 500 ppb evaluated over three hours has not been revised, and EPA is also not currently designating areas on the basis of the secondary standard.

General Approach and Schedule

Section 107(d) of the Clean Air Act requires that not later than one year after promulgation of a new or revised NAAQS, state g overnors must submit their recommendations for designations

and boundaries to EPA. Section 107(d) also requires EPA to provide notification to states no

less than 120 days prior to p romulgating an area designation that is a modification of a state’s

recommendation. If a state does not submit designation recommendations, EPA will promulgate the designations that it deems appropriate. If a state or tribe disagrees with EPA’s intended designations, they are given an opportunity within the 120

- day period to demonstrate why any proposed modification is inappropriate.

On August 5, 2013, EPA published a final rule establishing air quality designations for 29 areas in the United States for the 2010 SO 2 NAAQS, based on recorded air quality monitoring data

from 2009

- 2011 showing violations of the NAAQS (78 FR 47191). In that rulemaking, EPA committed to address, in separate future actions, the designations fo r all other areas for which the Agency was not yet prepared to issue designations.

Following the initial August 5, 2013 designations, three lawsuits were filed against EPA in

different U.S. District Courts, alleging the A gency had failed to perform a non discretionary duty

1 40 CFR 50.4(e) provides that the two prior primary NAAQS will no longer apply to an area one year after its designation under the 2010 NAAQS, except that for areas designated nonattainment under the prior NAAQS as of August 22, 2010, and areas not meeting the requirements of a SIP Call under the prior NAAQS, the prior NAAQS will apply until that area submits and EPA approves a SIP providing for attainment of the 2010 NAAQS.3

under the CAA by not designating all portions of the country by the June 2013 deadline. In an effort intended to resolve the litigation in one of those cases, plaintiffs Sierra Club and the

Natural Resou rces Defense Council and EPA file d a proposed consent decree with the U.S.

District Court for the Northern District of California

. On March 2, 2015, the court entered the

consent decree and issu ed an enforceable order for EPA to complete the area designations according to the consent dec ree schedule.

According to the c onsent decree and court order

, EPA must complete the remaining desi gnations on a schedule that contains three specific deadlines. By no later than July 2, 2016 (16 months from the court’s order)

, EPA must designate two groups of areas: (1) areas that have newly

monitored violations of the 2010 SO 2 NAAQS

, and (2) areas that contain any stationary s ources that ha d not been announced as of March 2, 2015 for retirement and that according to EPA ’s Air

Markets Datab a se emitted in 2012 either (i) more than 16,000 tons of SO 2 or (ii) mor e than 2,600

tons of SO 2 with an annual average emission rate of at least 0.45 pounds of SO 2 per one million British thermal units (lbs SO 2 /mmBTU)

. Specifically, a station ary source with a coal

- fired unit that as of January 1, 2010 had a capacity of over 5 megawatts and otherwise meets the emissions criteria, is excluded from the July 2, 2016 deadline if it had announced through a company public announcement, public utiliti es commission filing, consent decree, public legal settlement, final state or federal permit filing, or other similar means of communication, by March 2, 2015, that it will cease burning coal at that unit.

The last two deadlines for completing remaining designations are December 31, 2 0 17, and

Decembe r 31, 2020

. EPA has separ ately promulgated requirements for states and other air agencies to provide additional monitoring or modeling information on a timetable consistent wi th these designation deadlines. We expect this information to become available in time to help inform these subsequent designations

. These requirements were promulgated on August 2 1 , 2015 (80 FR 51052) , in a rule known as the SO 2 Data Requirements Rule (DRR)

.

Updated designat ions guidance was issued by EPA through a March 20, 2015 memorandum from Stephen D. Page, Director, U.S. EPA, Office of Air Quality Planning and Standards, to Air Division Directors, U.S. EPA Regions I

- X. This memorandum supersedes earlier designation gui dance for the 2010 SO 2 N AAQS, issued on March 24, 2011, and it i dentifies factors that EPA intends to evaluate in determining whether areas are in violation of the 2010 SO 2 NAAQS. The guidance also contains the factors EPA intends to evaluate in determining the boundaries for all remaining areas in the country, consistent with the court’s order and schedule. These factors

include: 1) Air quality characterization via ambient monitoring or dispersion modeling results;

2 ) Emissions

- related data; 3) Meteorology; 4) Geography and topography; and 5) Jurisdictional boundaries. This guidance was supplemented by two technical assistance

documents intended to assist states and other interested parties in their efforts to charac terize air quality through air dispersion modeling or ambient air quality monitoring for sources that emit

SO 2 . Notably, EPA released its most recent versions of documents titled, “SO 2 NAAQS Designations Modeling Technical Assistance Document” (Modeling TAD) and “SO 2 NAAQS Designations Source

- Oriented Monitoring Technical Assistance Document” (Monitoring TAD)

in December 2013.4

Based on ambient air quality data collected between 2012 a nd 2014, no violations of the 2010

SO 2 NAAQS have been recorded in a ny undesignated part of Maryland. 2 However, there is one

source in the state meeting the emissions criteria of the consent decree and court order for which EPA must complete designations by July 2, 2016. In this draft technical support document, EPA discusses its review and technical analysis of the area that we must designate pursuant to the

c onsent d ecree and c ourt order

. EPA also discusses any intended modifications from the S tate’s

recommendation based on all available data before us.

The following are d efinition s of important terms used in this document: 1) 2010 SO 2 NAAQS

– The primary NAAQS for SO 2 promulgated in 2010. This NAAQS is 75 ppb, based on the three

- year average of the 99th percentile of the annual distribution of daily maximum one

- hour average concentrations. See 40 CFR 50.17. 2) Design Value

- a statistic computed according to the data handling procedures of the NAAQS (in 40 CFR part 50 App endix T) that, by comparison to the level of the NAAQS, indicates whether the area is violating the NAAQS. 3) Designated nonattainment area

– an area which EPA has determined has violated the

2010 SO 2 NAAQS or contribute d to a violation in a nearby area. A nonattainment designation would reflect considerations of state recommendations and all of the

information discussed in this document. EPA’s decision would be based on all available

information incl uding the most recent three years of air quality monito ring data, available modeling analysis, and any other relevant information. 4) Designated unclass ifiable area

– an area which EPA cannot determine based on all

available information whether it meets the 2010 SO 2 NAAQS. 5) Designated unclassifiable/atta inmen t area

– an area which EPA has determined to have

sufficient evidence to find either is attaining or is likely to be attaining the NAAQS

. EPA’s decision would be based on all available informa tion including the most recent

three years of air quality monitoring data, available modeling analysis, and any other

relevant information. 6) Modeled violation

– a violation based on air dispersion modeling

. 7) Recommended attainment area

– an area a state o r tribe has recommended that EPA designate as attainment. 8) Recommended nonattainment area

– an area a state o r tribe has recommended that EPA designate as nonattainment. 9) Recommended unclassifiable area

– an area a state or tribe has recommended that EPA designate as unclassifiable.

2 For designations based on ambient air quality monitoring data that violates the 2010 SO 2 NAAQS, the consent

decree directs EPA to evaluate data collected between 2013 and 2015. Absent complete, quality

- assured and certified data for 2015, the analy ses of applicable areas for EPA’s intended designations will be informed by data

collec ted between 2012 and 2014. States with monitors that have recorded a violation of the 2010 SO 2 NAAQS during these years have the option of submitting complete, quality

- assured and certified data for calendar year 2015 by April 19, 2016 to EPA for evaluati on. If after our review, the ambient air quality data for the area indicates that no violation of the NAAQS occurred between 2013 and 2015, the conse nt decree does not obligate EPA to complete the designation. Instead, EPA may designate the area and all other previously undesignated areas in the state on a schedule consistent with the prescribed timing of the consent decree, i.e., by December 31, 2017, or December 31,

2020.5

10) Recommended unclassifiable/attainment area

– an area a state or tribe h as recommended

that EPA designate as unclassifiable/attainment. 11) Violating monitor

– an ambient air monitor meeting all methods, quality assurance and siting criteria and requirements whose valid design value exceeds 75 ppb, based on data analysis conducted in accordance with Appendix T of 40 CFR part 50.6

Technical Analysis for the Anne Arundel County and Baltimore County

, Maryland Area and Baltimore City, Maryland Area

Introduction

The Anne Arundel County and Baltimore County area contains one stationa ry source that according to EPA’s Air Markets Database emitted in 2012 either (a) more than 16,000 tons of

SO 2 or (b) more than 2,600 tons of SO 2 and had an annual average emission rate of at least 0.45

lbs SO 2 /mmBTU

. As of March 2, 2015, this stationary source , Herbert A. Wagner Generating Station (Wagner , or the Facility ), had not met the specific requirements for be ing “announced for

retirement.” 3 Specifically, in 2012

, Wagner emitted 7,514 tons of SO 2 , and had an emissions rate

of 1.105 lbs SO 2 /mmBTU. Pursuant to the Ma rch 2, 2015 consent decree and court order, EPA must designate the area surrounding the facility by July 2, 2016.

In its April 19, 2011 submission to EPA for the initial designations for the 2010 SO 2 NAAQS

, Maryland recommended that the area which includes Wagner, specifically the entirety of Anne

Arundel County, be designated as unclassifiable. Likewise, Maryland’s 2011 submission recommended that Baltimore City be designated as unclassifiable. The 2011 submission, however, did not include any supporting analyses. Subsequently, in its November 20, 2015 updated designation recommendation submission to EPA, Maryland recommended that the area surrounding Wagner be designated as attainment. Maryland , however, did not recommend any particular boundary for the area in its November 20, 2015 submission

. Maryland stated that no monitors in Maryland violated the 1

- hour SO 2 NAAQS

, and EPA has confirmed this

. On January 15, 2016, Maryland submitted a supplement to its 2015 recommendation which included a modeling analysis for the area around Wagner. Additionally, this supplement included comments on air dispersion modeling dated January 4, 2016, performed by Sierra Club and submitted to EPA, asserting that violations of the NAAQS are present in the area around Wag ner. Maryland did not update its recommendation for Baltimore City in its 2015 updated

recommendation. After careful review of the S tate’s 2015 recommendation and all submitted

avail able data including air quality charact erization, emissions data, mete orology, geography, topography , and modeling analyses for the area around Wagner

, EPA dis agrees with the S tate’s

recommendations , and intends to designate the area surrounding Wagner ( portions of Anne Arundel County and Baltimore County) as nonattainment

, and Baltimore City as

unclassifiable/attainment.

Wagner is located in eastern Maryland in the northern portion of Anne Arundel County

. As seen in Figure 1, the facility 4 is located approximately two (2) kilometers south of the City of

3 However, Wagner Unit 2 is on PJM Interconnection L LC ’s (PJM) current list for projected deactivation by June 1,

2020. See PJM’s projected deactivation list, dated November 25, 2015, available at http://www.pjm.com/~/media/planning/gen

- retire/pending

- deactivation

requests.ashxhttp://www.pjm.com/~/media/planning/gen

- retire/pending

- deactivation

- requests.ashx

. PJM is a regional tran smission organization (RTO) that coordinates the movement of wholesale electricity in all or parts of 13 states, including Maryland, and the District of Columbia.

4 EPA notes that the Wagner facility is considered one stationary source for purposes of Titl e V of the CAA and for

CAA New Source Review (NSR) purposes with the Brandon Shores Generating Station (Brandon Shores) also7

Baltimore along th e Chesapeake Bay

. Also included in the figure is EPA’s intended

nonattainment designation for the area. Specifically, the boundaries for our intended nonattainment area are comprised of the portions of Anne Arundel and Baltimore Counties that

are within 35.5 kilometers of Herbert Wagner’s Unit 3 stack, which is located at 39.17765N latitude, 76.52752W longitude

.

Figure 1 : EPA’s Intended D esignation for Anne Arundel County and Baltimore County A rea

The discussion and analysis that follows below will reference the factors for evaluation

contained in EPA’s March 20, 2015 guidance, as appropriate.

Detailed Assessment for Anne Arundel County and Baltimore County Area

Air Quality Data

This factor considers the SO 2 air quality monitoring data in the area surrounding Wagner

. The

F acility is located in Anne Arundel County; however, there are no ambient air quality m onitors located in this county. There is an ambient air quality monitor geographicall y near Anne

owned and operated by the same entity which owns and operates Wagner . Collectively, the facilities are known as

“Fort Smallwood” a nd are subject to one Title V CAA permit issued by Maryland

.8

Arundel in Baltimore County. Maryland ’s update d 2015 designation recommendation included design values and the maximum 1

- hour SO 2 concentrations from 2007

- 2014 for the Essex

monitor (Air Quality Systems (AQS) ID 24

- 005

- 3001) , located in Baltimore County ( see Table 2)

. The State notes that the design value has decreased since the implementation of Maryland’s Healthy Air Act. This monitor, however, is not located near Wagner and is instead located i n neighboring Baltimore C ounty , approxim ately 15 kilometers northeast of Wagner. As a result of this distance, EPA does not believe that the Essex monitor adequately characterizes air quality as a result of emissions from Wagner.

Table 2 : Maryland’s SO 2 Emissions and Air Monitoring Concentrations in the Vicinity of Wagner (in Maryland’s November 20, 2015 submission)

SO 2 Emissions (Tons/Year) SO 2 Concentrations at Essex (ppb) Year Total Brandon Shores Wagner Crane Design

Value* Max 1

- hour

2007 92,931 42,041 20,259 30,631 99 173

2008 79,282 39,924 15,006 24,352 86 66

2009 60,391 32,821 15,093 12,477 80 56

2010 15,877 1,260 9,028 5,589 43 33

2011 17,518 2,829 9,007 5,682 34 53

2012 12,494 2,848 7,473 2,173 22 26

2013 16,020 2,870 10,178 2,972 22 31

2014 14,643 3,145 9,610 1,887 22 44
*The design value for the 1

- hour SO 2 standard is the 99th percentile of the 1

- hour daily maximum concentrations, averaged over three years. The 1

- hour SO 2 standard is 75 parts per billion (ppb), calculated the same way.

Nonetheless, EPA has reviewed the most recent three years of monitoring data, i.e., 2012

– 2014

, for the Essex monitor since there are no monitors in Anne Arundel C ounty and the Essex

monitor is the closest monitor to Wagner. T able 3 below shows the data from the Essex monitor

which were confirmed through EPA’s 2014 design value report for SO 2

. 5

Table 3 : Available Air Quality Data Near Wagner
County Air Quality

Systems (AQS)

Monitor ID Monitor Name Distance to Wagner (km) 2012

– 2014 SO 2

Design Value in ppb

Baltimore 24

- 005

- 3001 Essex 15 22

EPA’s more detailed examination of d aily peak 1

- hour SO 2 concentrations and the 99 th percentile daily 1

- hour max imum SO 2 concentration s i s also p resent ed to gauge how high concentrations are in the vicinity of Wagner

. The 99 th percentile daily peak 1

- hour concentrations are shown in

Table 4 for the 2012

- 14 time period along with the 99 th percentile for the Essex monitor. The

Essex monitor’s daily peak 1

- hour SO 2 concentrations exceeded 50 percent of the NAAQS on one (1) day during the 2012

- 14 time period.

5 The design value report for SO 2

, as well as each of the other NAAQS, can be found at this link: http://www3.epa.gov/airtrends/values.html

.9

Table 4 : Additional Monitoring Data for the Essex Monitor (24

- 005

- 3001)
Day ’ s Peak 1

- Hour > 37.5 ppb Total Valid

Days 2012

- 1 4 %Valid Days

2012

- 14 99 th

percentile

2012 99 th percentile

2013 99 th percentile

2014

1 1,084 98.9% 19 39 26

In addition, EPA’s evaluation of the monitoring data indicates that 1

- hour SO 2 concentrations at

the Beltsville monitor ( AQS ID 24

- 033

- 0030) in neighboring Prince George’s County are less

than half of those observed at Essex. This monitor is approximately 33 km west southwest of Wagner. Beltsville, unfortunately, d oes not meet the completeness criteria required to generate a valid design valu e though nearly 96 percent of the days were “ complete

. ” There were n o days during the 2012

- 14 time period that exceeded 50 percent of the NAAQS at Beltsville.

Based on available ambient air quality data collected between 2012 and 2014, Anne Arundel’s

nei ghboring county, Baltimore County, does not show a violation of the 2010 SO 2 NAAQS at its

monitor. O ver the last two years there was only one (1) day in which 1

- hour SO 2 concentrations

exceeded 50 percent of the NAAQS. 6 However, the absence of a violating monitor when considering the distance from the F acility is not a sufficient technical justification to rule out that

an exceedance of the 2010 SO 2 NAAQS may occur in the immediate vicinity of the F acility.

Additionally , Maryland’s November 20, 2015 recommendation references a 2013 two

- month monitoring study of SO 2 concentrations conducted around Raven Power’s Wagner, Brandon
Shores, and C.P. Crane facilities

, and Maryland states that peak daily 1

- hour maximum

monitored SO 2 values were generally below 75 ppb

, even though one site had a daily peak (101.7 ppb) that exceeded the 1

- hour SO 2 NAAQS

. The limited duration of this study does not allow

EPA to make a determination of how f r equently the NAAQS is exceeded, but given the

occurrence of a maximum 1

- hour SO 2 concentration of 101.7 ppb at the monitor closest to the

F acility during the summer months, which is far in excess of the 75 ppb standard, an extrapolation would indicate that at least one exceedance of the NAAQS occurs quarterly. It must be noted, however

, that EPA was not provided with any detailed information to p ermit EPA to evaluate the study, critically analyze the study’s data, nor draw any conclusions from the study

at this time . For instance, EPA has no information on how this study was conducted , who

maintained the monitors in the study, what quality control checks were done on the monitors, n or any other critical information such as under what conditions this mon itoring study was

conducted

. Given this information, t here is a lack of supporting evidence to support an attainment designation for the area surrounding Wa gner.

Emissions and Emissions

- Related Data

Evidence of SO 2 emissions from the Facility meeting the emissions criteria of the March 2, 2015

consent decree and the court order is an important factor for determining whether the immediate area is experiencing elevated levels of SO 2 concentrations. Other considerations for this factor

include c ounty level SO 2 emissions data, and d ata for sources located within 50 km.

6 See Maryland’s November 20, 2015 designation recommendation, attachment 3, T able 2.10

Maryland ’s updated 2015 designation recommendation include d annual emissions data for

sources in Anne Arundel County (i.e. Wagner and Brandon Shores)

, as well as annual emissions data from sources in neighboring Baltimore County (i.e. Crane)

. Maryland notes that implementation of Maryland’s Healthy Air Act in 2010 resulted in a decrease of SO 2 emissions from Wagner, Brandon S hores, and Crane. Maryland’s recommendation included the data provided in T able 2 above

.

EPA confirms that e missions had decreased significantly from 2007 to 2010 ; however, they have not decreased since then, and have in fact increased slightly in 2014 from the 2010 leve l. Additionally, Wagner had been identified in 2015 as meeting the emission criteria outlined in the

co urt order

, and Wagner’s emissions have not decreased further since 2010 with its SO 2 emissions remain ing between 9,000 and 10,000 tons per year, As a result, EPA believes that this emissions data alone does not support the attainment designation recommended by Maryland. Wagner’s emissions also have not decreased as significantly as Brandon Shore’s and Crane’s

, which may reflect an absence or und er

- use of SO 2 controls.

To evaluate what emission controls are installed for Wagner and neighboring sources, EPA reviewed its Air Markets Programs (AMP) database. According to the AMP database, Brandon Shores has wet lime flue gas desulfurization (FGD) on Unit 1 and wet limestone SO 2 control for

Unit 2. No SO 2 controls are listed in the EPA database for Wagner or C.P. Crane. Table 5 summarizes unit level controls and fuel types for the eight (8) primary combustion units at Wagner, Brandon Shores and C. P. Crane from the AMP database. With t he lack of SO 2 emissions controls at Wagner and the present level of emissions at the plant

, EPA lacks sufficient supporting evidence to support an attainment designation for the area around Wagner as Maryland has recommended.

Table 5: Air Markets Program Information for Brandon Shores, Wagner and C.P

. Crane Facility Name Unit Fuel Type

(Primary) Fuel Type

(Secondary) SO 2

Control(s) Particulate

Matter ( PM ) Control(s) Mercury ( Hg )

Control(s)

Brandon

Shores 1 Coal

- Wet Lime

FGD Cyclone

Baghouse -

Brandon

Shores 2 Coal

- Wet

Limestone Cyclone

Baghouse -

Herbert A Wagner 1 Other Oil Pipeline

Natural Gas - Electrostatic Precipitator -

Herbert A Wagner 2 Coal

- - Electrostatic Precipitator Halogenated

PAC Sorbent Injection

Herbert A Wagner 3 Coal

- - Electrostatic Precipitator -

Herbert A Wagner 4 Other Oil Pipeline

Natural Gas - Electrostatic Precipitator -

C P Crane 1 Coal

- - Baghouse

- C P Crane 2 Coal

- - Baghouse

-11

Further, EPA reviewed th e emissions data provided by Maryland and confirmed the data by

evalu ating data obtained from the 2011 and 2013 National Emissions Inventory (NEI). 7 The

annual SO 2 emissions data for point sources emitting at or above 100 tons per year (tpy) in Anne

Arundel and neighboring Baltimore County and Baltimore City are summarized in Table 6

below. Figure 2 shows the locations of the emissions sources listed in Table 6 . One source labeled in Figure 2 , Sparrows Point, LLC, however, is not included in Table 6 becaus e it has been permanently shut down and demolished. 8

Table 6 : 2011 and 2013 NEI SO 2 Emissions from Wagner and Other Local Sources
County Owner and

Operator Facility

Complex

Name Facility

Name Facility

Subject to

the

Emissions

Criteria of

the March
2, 2015

consent
decree? Distance

to Facility

that

Meets

the

Consent

Decree

Criteria

in km 2011

Facility

Total SO 2 Emissions (tpy) 2013

Facility

Total SO 2 Emissions (tpy)

Anne

Arundel Raven Power

Holdings,

LLC Fort

Smallwood 9 Wagner Yes 0 11,943 10 13,049 9

Anne

Arundel Raven Power

Holdings,

LLC Fort

Smallwood Brandon

Shores No 0 11,943 9 13,049 9

Baltimore Raven Power

Holdings,

LLC N/A C.P. Crane

LLC No 22 5,684 2,973

Baltimore City Wheelabrator

Technologies N/A Wheelab

rator Baltimore,

L

. P

. No 12.9 261 321

EPA has also reviewed emissions data from EPA’s A MP database. For 2014, Wagner’s SO 2 emissions were 9 ,610 tpy and Brandon Shores were 3 ,145 tpy. Figure 3 shows annual SO 2 emissions for each unit from EPA’s A MP

. Of the eight (8) units reviewed, Wagner ’s u nit 3

7 Detailed information for the 2011 NEI can be found at this link: http://www3.epa.gov/ttnchie1/net/2011inventory.html . For more information on the 2013 NEI, contact the Region

III office.

8 The facility’s Title V permit has expired.

9 As discussed above, Brandon Shores and Wagner are treated as a single stationary source for Title V and NSR

purposes due to common ownership by Raven Power Holdings, LLC, contiguous location, and same singular major industrial grouping

. 10 In both the 2011 and 2013 NEI, emissions from Wagner and Brandon Shores are combined and reported together as Wagner and Brandon Sho res are treated as a single stationary source

. Emissions from each facility, however, are reported individually in EPA’s Air Markets Database as 9,610 tpy for Wagner in 2014 and 3,145 tpy for Brandon

Shores in 2014.12

emitted the largest amount of SO 2 during the 2012

- 14 time period . It should be noted that unit 3 does not have any SO 2 emission control devices installed.

Figure 2 : 2013 NEI Annual SO 2 Emissions in tons per year13

Figure 3: 2012

- 14 Annual Unit SO 2 Emissions in tpy from Wagner, Brandon Shores and Crane

The lack of SO 2 emissions controls at Wagner, lack of declining emissions trend from Wagner, and the present level of emissions at the plant indicates that there could be impacts from this plant on SO 2 concentrations in the area . EPA lacks sufficient supporting evidence to support an attainment designation for the area around Wagner as Maryland has recommended . Based on EPA’s review of available emissions data, as well as air dispersion modeling information for the area surrounding Wagner discussed later in this draft t echnical support document, EPA believes a designation of nonattainment is appropriate for the area impacted by Wagner.

Emissions Controls

Maryland’s updated 2015 designation recommendation mentions that in mid

- April 2015, the owners of the Wagner facilit y, Raven Power, began to use a low sulfur coal at Wagner’s unit 2 as a method of compliance with the federal Mercury and Air Toxics Standard (MATS). However, EPA has insufficient information on the percent sulfur coal and whether any restrictions on fuel 0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000 9,000

Herbert A

Wagner

Unit 1 Herbert A

Wagner

Unit 2 Herbert A

Wagner

Unit 3 Herbert A

Wagner

Unit 4 Brandon

Shores Unit

1 Brandon

Shores Unit

2 C P Crane

Unit 1 C P Crane

Unit 2 

## Raven Power

- CAMD SO 2 

## Emissions 2012

- 14

2012 (tons) 2013 (tons) 2014 (tons)14

sulfur coal are in a permanent, federally enforceable document such as a permit or SIP approved requirement. Maryland also mentions that in early 2016, Raven Power will be adding a dry sorbent injection (DSI) system to Wagner’ s unit 3 to comply with MATS to help reduce SO 2 emissions. Again, EPA has no further information at this time regarding the specifications of the DSI system, its control efficiency, and operational requirements and no information on whether DSI controls are federally enforceable vi a permits or SIP requirements. In addition, review of Wagner’s unit

- by

- unit emissions reveals that emissions of SO 2 from Wagner’s unit 3 are far greater than that of unit 2 and hence EPA believes controls and effectiveness of controls at unit 3

at reducin g SO 2 are more important to any analysis of impacts from the plant

. At this time, there are no federally enforceable controls in place at the plant to reduce SO 2 , and Wagner’s obligations to comply with the federal MATs requirements is no t sufficient to a llow EPA to fully

evaluate future likely impacts from Wagner on the NAAQS , and are not relevant for evaluating

whether actual emission s from 2012

- 2014 caused violations of the NAAQS during that period

. Maryland has not presented any analysis or informatio n to support that MATS compliance plans

will reduce SO 2 emissions from Wagner to such an extent that the SO 2 NAAQS are met

. Present information from Maryland regarding potential control options at the plant and fuel switching options without federally enforceable controls and limits is insufficient to support Maryland’s

recommend ation of attainment for the area. Furthermore, based on EPA’s review of emissions control information in conjunction with available air dispersion modeling discussed later in t his

draft technical support document, EPA believes a designation of nonattainment is appropriate for the area around Wagner.

Meteorology (Weather & Transport Patterns)

Maryland’s updated 2015 designation recommendation did not address meteorology . Mar yland did not provide a discussion of the meteorology, nor any analysis or impacts of this factor on the area around Wagner.

Evidence of source

- receptor relationships between specific emissions sources and high SO 2 concentrations in the surrounding area is an important factor in determini ng the appropriate

extent of EPA’s int ended nonattainment area. The closes t hourly reporting meteorological monitoring station to Wagner is the Baltimore

- Washington International Airport (BWI). BWI is located approximately twelve (12) kilometers west of Wagner. A wind rose for the 2 012

- 14 time period ( Figure 4 ) shows predominantly westerly winds in the area.15 Figure 4 : BWI 2012

- 14 Wind Rose16 Figure 5 : Location of BWI Monitoring Location

Geography and Topography (Mountain Ranges or Other Air Basin Boundaries)

Maryland’s updated 2015 designation recommendation did not explicitly address this factor. Maryland did provide two topographical maps showing monitoring locations, but did not pro vide a discussion of the geography or topography, nor any anal ysis or impa cts of this factor on the area around Wagner

.

EPA has reviewed both the geography and topography of the area surrounding Wagner. Wagner and Anne Arundel County lie within the Atl antic Coastal Pla i n just west of the Chesapeake Bay (Figure 5 ) . Elevations at the F acility are slightly above sea level. Stack heights at the F acility exceed 80 meters. This means that nearly all of the terrain in Anne Arundel County lies below the stack tops preventing potential plumes from directly impacting any nearby terrain features. The nearest terrain features lie over seventeen (17) kil ometers northwest of Wagner.

As noted in EPA’s Modeling TAD, , in areas of flat terrain, such as the area surrounding Wagner , the distance to maximum concentration is generally expected to fall within a distance of ten (10) stack heights or approximately 1 kilometer from Wagner. Given the lack of terrain, and17

using general modeling principals from EPA’s Modeling TAD we expect maximum concentrations to occur within a kilometer or so from Wagner. The expected localized impact from Wagner is supported in information from the Summer 2013 Monitoring Study submitted by Maryland. Monitoring data from this study showed the Cianbro Site, located approximately three (3) kilometers west of Wagner, exceeded the 1

- hr SO 2 NAAQS on one occasion. Although this information supports expected maximum concentrations to occur within a kilometer or so from Wagner, based on general weste rly/northwesterly wind patterns and the lack of terrain, it is

reasonable to conclude that transport may play some role in dispersing SO 2 downwind, and thereby causing additional violations of the SO 2 NAAQS farther than a kilometer from the facility. Base d on EPA’s review of this information, EPA believes there is insufficient evidence to support an attainment designation for the area surrounding Wagner. Furthermore, based EPA’s review of available air dispersion modeling discussed later in this technical support
document , EPA believes a designation of nonattainment is appropriate for the area impacted by Wagner.

Figure 6 : Elevation/Topography of Anne Arundel and Surrounding Counties18

Air Dispersion Modeling

Detailed Assessment of Maryland ’s Modeling

In its November 20, 2015 recommendation, Maryland included a narrative describing preliminary modeling analyses that were being conducted by the State. The State notes that the modeling uses 2012

- 2014 actual emissions data, including the reducti ons in 2015 being seen

from the use of low

- sulfur coal for compliance with MATS at Wagner’s u nit 2 . EPA, however, is not aware of any federally enforceable restrictions on the Wagner plant regarding fuel sulfur limits or any SO 2 controls. The State furth ermore notes that the preliminary modeling includes emission units of Wagner, Brandon Shores, Crane, Wheelabrator and Energy Answers, and that background concentrations were based on a season and hour

- of

- day approach delineated in EPA guidance. On January 15, 2016, Maryland submitted a set of modeling files and a final modeling

report as a supplement to its 2015 recommendation. Additionally, Maryland also included comments on the modeling analysis submitted by Sierra Club on January 4. 2016 , which can be

found in the docket

.

Model Selection and Modeling Components

EPA’s draft Modeling TAD notes that for area designations under the 2010 SO 2 NAAQS, the AERMOD modeling system should be used, unless use of an alternative model can be justified.

In some instances the recommended model may be a model other than AERMOD, such as the BLP model for buoyant line sources. The AERMOD modeling system contains the following

components:

- AERMOD: the dispersion model

- AERMAP: the terrain processor for AERMOD

- AERMET: the meteorological data processor for AERMOD

- BPIPPRIME: the building input processor

- AERMINUTE: a pre

- processor to AERMET incorporating 1

- minute automated surface observation system (ASOS) wind data

- AERSURFACE: the surface characteristics processor for A ERMET

- AERSCREEN: a screening version of AERMOD

In June of 2015 the Maryland Department of the Environment (MDE) provided a modeling analysis to Raven Power, the owner of Wagner, Brandon Shore (collectively known as Fort Smallwood) and Crane generating sta tions. Raven Power then contacted AECOM to review and update MDE’s modeling analysis.

Modeling components used by AECOM are summarized in Table 7 . The modeling appears to have been completed in January 2016. AECOM included building downwash for the Wag ner, Brandon Shores and Crane generating stations. No building downwash was determined for Wheelabrator Baltimore and Energy Answers, though this information was included in Energy Answers’ PSD/NSR application modeling.19

Table 7: Model Versions Summary
AERMOD Component AECOM Version Current Version

AERMOD 15181 15181

AERSURFACE 13016 13016

AERMAP

- 11103

AERMET 15181 15181

AERMINUTE 14337 15272

BPIPPRIME 04274 04274

Modeling Parameter: Rural or Urban Dispersion

EPA’s recommended procedure for characterizing an area by prevalent land use is based on evaluating the dispersion environment with 3 km of the facility. According to EPA’s modeling guidelines, rural dispersion coefficients are to be used in the dispersion modeling analysis if

more than 50% of the area within a 3 km radius of the facility is classified as rural. Conversely, if more than 50% of the area is urban, urban dispersion coefficients should be used in the modeling analysis. AECOM’s modeling analysis utilized rural dispersion coeff icients in its AERMOD runs. This conclusion was based on a visual inspection of 2011 Land Use Land Cover (LULC) information within three (3) kilometers of Fort Smallwood. When performing the modeling for the area of analysis, AECOM determined that it was most appropriate to run the

model in rural mode. No analysis was done to determine if effective stack height exceeded any urban mixed layer that could be occurring over the City of Baltimore ( see section 5.1 of EPA’s AERMOD Implementation Guide ). The est imated urban boundary layer is 298.8 meters ( see equation (1) in previous noted section of EPA guidance).

Modeling Parameter: Area of Analysis (Receptor Grid)

EPA believes that a reasonable first step towards characterization of air quality in the area surrounding the Herbert A. Wagner Generating Station is to determine the extent of the area of analysis, i.e., receptor grid. Considerations presented in the draft Modeling TAD include but are

not limited to: the location of the SO 2 emission sources or facilities considered for modeling; the extent of significant concentration gradients of nearby sources; and sufficient receptor coverage and density to adequately capture and resolve the model predicted maximum SO 2 concentrations.

For the Wagner area, AECOM has included a total of ten (10) SO 2 sources within twenty ( 20 ) kilometers (km) of the Herbert A. Wagner Generating Station

. This generally follows guidance outlined in EPA’s March 1, 2011 Clarification Memo entitled Additional Cla rification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 , National Ambient Air Quality 11

. Standard AECOM included sources controlled by Raven Power (Wagner, Brandon Shores and Crane) along with the Baltimore Incinerator ( Wheelabrator Baltimore) and the proposed Energy Answers municipal waste incinerator

.

Imbedded Cartesian receptor grids were developed by AECOM surrounding the Fort Smallwood complex (Brandon Shores and Wagner) and Crane. The receptor grids were develope d as follows:

11 Top paragraph page 1620

- 25 meter spacing along both facility’s property boundary

- 100 meter spacing out to two (2) km

- 250 meter spacing between two (2) and five (5) km

- 500 meter spacing between five (5) and ten (10) km

The model receptor network contained a total of 6,181 receptors

. Model receptors were placed in Anne Arundel and Baltimore counties and Baltimore City

. AECOM followed EPA’s Modeling TAD and attempted to remove receptors that were located over open water and other

sites where it would not be feasible to site an actual monitor and record ambient impacts

. Figure

7 show s AECOM ’s chosen area of analysis surrounding the Herbert A. Wagner Generating

Station , as well as receptor grid for the area of analysis.

Figure 7: AECOM’s Model R eceptor Grid for the W agner Area of Analysis

Modeling Parameter: Source Characterization

AECOM characterized t en (10) source s within the area of analysis in accordance with the best practices outlined in the Modeling TAD. All sources were modeled as point sources with no horizontal or obstructed stacks. These included all the major SO 2 sources operated by Raven Power along with two (2) other sources. All coal

- fired units were included in the modeling analysis along with two (2) large oil

- fired units at Wagner that make up the Fort Smallwood21

complex. Smaller ancillary emission sources and start

- up/shut

- down emissions were not included in AECOM’s modeling analysis.

Additional stack information is summarized in Table 8 . T his includes information on emission rates, hourly varying stack parameters and how well sources using actual hourly emission rates compare to those rates pulled from EPA’s Clear Air Markets website 12 . In general, Raven Power’s modeled hourly emissions mat ched those extracted from the Clean Air Market’s

website.

Table 8 : Summary of Stack Information for Facilities in the Wagner Area of Analysis

AECOM Source Model Emission

Rate Hourly Emission

Matches CAMD Variable

Stack Temp Variable Stack

Velocity

Crane 1 Actual, Hourly Nearly Identical No No

Crane 2 Actual, Hourly Nearly Identical No No

Brandon Shores 1 Actual, Hourly Nearly Identical Yes Yes

Brandon Shores 2 Actual, Hourly Nearly Identical Yes Yes Wagner 1 Actual, Hourly Nearly Identical No No Wagner 2 Adjusted

Actual, Hourly Adjusted to

1.0 lb/MMBtu Yes Yes

Wagner 3 Actual, Hourly Nearly Identical Yes Yes Wagner 4 Actual, Hourly Nearly Identical No No

Whe e labrator

Baltimore Allowable NA No No

Energy Answers Allowable NA No No

Stack parameters pulled from EPA’s 2011 National Emissions Inventory (NEI) are listed for comparison to AECOM’s. Additionally, stack parameters for Energy Answers were pulled from its PSD/NSR application. The physical stack parameters (stack heights and stack diameters) from both data sets generally match. There is a slight discrepancy in Wheelabrator Baltimore’s stack diameter. An equivalent stack diameter was taken based on the 2011 NEI since Wheelabrator’s stack appears to have three flues contained in one stack (each 2.13 m in diameter). AECOM’s stack parameters for Energy Answers are identical to those contained in its PSD/NSR application modeling analysis accept for the stack diameter, which was significantly larger in the application. There were also slight differences , i.e., a few meters, in the stack base elevations for Wheelabrator Baltimore and Energy Answers.

AECOM used a merged stack technique when Brandon Shore Units 1 & 2 operated simultaneously. This is in accordance with EPA Clearing House Memorandum 91

- II

- 01 and is an appropriate modeling technique since both units share a common stack (dual

- flue stack). Merging the stacks will slightly enhance the stack velocity and final plume rise. Again, this only

occurs when both Brandon Shore units are operating.

12 http://ampd.epa.gov/ampd/22

Table 9: AECOM Stack Parameters

Facility Unit Stack Height (m) Stack

Temperature (K) Stack

Velocity (m/s) Stack

Diameter (m)

Fort Smallwood Brandon Unit 1 121.92 324.817 15.073 9.5

Fort Smallwood Brandon Unit 2 121.92 324.817 14.895 9.5

Fort Smallwood Wagner Unit 1 87.478 330 30.48 3.099

Fort Smallwood Wagner Unit 2 87.48 422.039 30.48 3.1

Fort Smallwood Wagner Unit 3 105.46 416.48 33.817 4.215

Fort Smallwood Wagner Unit 4 104.242 610.928 35.3568 5.334

C.P. Crane Crane Stack 1 107.594 435.93 30.48 3.328

C.P. Crane Crane Stack 2 107.59 438.71 30.48 3.33

Wheelabrator

Baltimore 96.01 485.93 22.55 2.13

Energy Answers 89.92 439.26 25.94 1.2984

Table 10: EPA 2011 (Version 1) NEI Stack Parameters

Facility Unit Stack Height (m) Stack

Temperature (K) Stack

Velocity (m/s) Stack

Diameter (m)

Fort Smallwood Brandon Unit 1 121.9 325.4 17.0 9.60

Fort Smallwood Brandon Unit 2 121.9 325.4 17.0 9.60

Fort Smallwood Wagner Unit 1 87.5 438.7 30.5 3.11

Fort Smallwood Wagner Unit 2 87.5 438.7 30.3 3.11

Fort Smallwood Wagner Unit 3 105.5 430.4 32.4 4.11

Fort Smallwood Wagner Unit 4 104.2 610.9 35.4 5.33

C.P. Crane Crane Stack 1 107.6 438.7 30.3 3.32

C.P. Crane Crane Stack 2 107.6 433.2 30.3 3.32

Wheelabrator

Baltimore 96.0 485.9 22.6 3.70

Table 11: Energy Answers Application (100% Load Run)

Facility Unit Stack Height (m) Stack

Temperature (K) Stack

Velocity (m/s) Stack

Diameter (m) Energy Answers 89.92 439.26 25.94 4.26

Modeling Parameter: Emissions

EPA’s Modeling TAD notes that for the purposes of modeling to characterize air quality for use in designations, the recommended appr oach is to use the most recent three years of actual emissions data and concurrent meteorological data. However, the Modeling TAD does provide for the flexibility of using allowable emissions in the form of the most recently permitted, (referred to as PTE or allowable) emissions rate.23

EPA believes that continuous emissions monitor ing systems (CEMS) data provide acceptable

historica l emissions information when it is available, and that these data are available for many electric generating units. I n the absence of CEMS data, EPA’s draft Modeling TAD highly encourages the use of AERMOD’s hourly varying emissions keyword HOUREMIS, or t hrough the use of AERMOD’s variable emissions factors keyword EMISFACT. When cho osing one of these methods, EPA believes that detailed throughput, operating schedules, and emissions information from the impacted source(s) should be used.

In certain instances, states and other interested parties may find that it is more advantageous or simpler to use PTE rates as part of their modeling runs. Specifically, a facility may have recently adopted a new federally enforceable emissions limit, been subject to a federally enforceable consent decree, or implemented other federally enforceable mechanisms and control technologies to limit SO 2 emissions to a level that indicates compliance with the NAAQS. The se new limits or conditions may be used in the applica tion of AERMOD. In these cases, the Modeling TAD notes that the existing SO 2 emissions inventories used for permitting or SIP planning demonstrations should contain the necessary emissions information for designations

related modeling. In the event that these short

- term emissions are not readily available, they may be calculated using the methodology in Table 8

- 1 of Appendix W to 40 CFR Part 51 titled, “Guideline on Air Quality Models.”

As previously noted, AECOM included ten (10) sources in its SO 2 mod eling analysis. AECOM

selected and refined these sources based on earlier modeling conducted by MDE. These sources

should adequately represent the area where maximum concentrations of SO 2 are expected to occur and adequately includes the sources which might contribute to those concentrations. There are no other larges sources of SO 2 that have the potential to cause significant concentration gradients within the area of analysis. For this area of analysis, AECOM used a hybrid approach,

where emissions from most of the sources are expressed as actual emissions, two (2) sources

used non

- federally enforceable emission rates and one (1) source adjusted its historic actual emission rates to account for a fuel switch that has recently reduced the unit’s actua l SO 2 emissions

. Table s 12

- 14 s ummarize the total emissions included in the modeling analysis. Source totals represent a mix of actual, non

- federally enforceable and adjusted emission rates.

Table 12: Actual Emissions

Company ID Facility Name Unit SO 2 Emissions (tons per year)

2012 2013 2014

Raven Power Brandon Shores 1 1,546.9 1,389.0 1,669.9

Raven Power Brandon Shores 2 1,301.3 1,481.3 1,475.2

Raven Power Wagner 1 0.2 0.2 72.6

Raven Power Wagner 2 2,512.8 1,551.3 1,939.0

Raven Power Wagner 3 4,960.2 8,553.5 7,276.1

Raven Power Wagner 4 41.2 72.7 322.5

Raven Power Crane 1 1,212.0 831.3 573.4

Raven Power Crane 2 961.2 2,140.3 1,313.8

Total Emissions All Facilities 12,535.8 16,019.6 14,642.524

Table 13: Adjusted Emissions Rate Sources

Company ID Adjusted emissions

rates (tons per year) 2011 NEI v1 (tons per year)

Wheelabrator Baltimore 439.2 261.3
Energy Answers 479.6

Table 14: Adjusted Wagner Unit 2 Emissions

Unit Emission Rate SO 2 Emissions (tons per year)

2012 2013 2014
Wagner Unit 2 Actual 2,512.8 1,551.3 1,939.0

Wagner Unit 2 Adjusted (1.0 lbs/MMBtu) 2,219.5 1,139.2 1,421.7

Modeling Parameter: Meteorology and Surface Characteristics

The most recent three (3) years of meteorological data (concurrent with the most recent three years of emissions data) should be used in designations efforts. As noted in the Modeling TAD, the selection of data should be based on spatial and climatologica l (temporal) representativeness. The representativeness of the data are based on: 1) the proximity of the meteorological monitoring site to the area under consideration, 2) the complexity of terrain, 3) the exposure of the meteorological site, and 4) the period of time during which data are collected. Sources of meteorological data include National Weather Service (NWS) stations, site

- specific or onsite data, and other sources such as universities, Federal Aviation Administration (FAA), and military stati ons.

For the Wagner area of analysis, AECOM used surface meteorology from Baltimore

- Washington International Airport (BWI). Meteorological data was concurrent with the hourly emission date used in the modeling analysis (2012

- 14). AECOM’s AERMOD file spe cified BWI’s station elevation as 4.4 meters; the station’s actual elevation is 45 meters. AECOM did not provide any documentation to determine if the meteorological data is representative of the Wagner area.

BWI is the closest ASOS first order station a nd is located a little over 10 kilometers west of Fort Smallwood ( see Figure 9 ). Upper Air data used in AERMET was taken from Sterling, VA, which is part of Dulles Airport (IAD) and is located approximately 82 kilometers west

- southwest

of Fort Smallwood. AECOM processed the data using AERMET’s Adjust U* non

- default option. This process adjusts the surface friction velocity for periods of low wind speeds.

EPA notes that the use of beta options, such as ADJ_U* and LOWWIND3, in AERMOD for any regulatory ap plications requires adherence with Appendix W, Section 3.2.2. T his is further explained in EPA’s December 10, 2015 Memorandum titled, “Clarification on the Approval Process for Regulatory Application of the AERMOD Modeling System Beta Options.” Among

oth er conditions, the use of beta options requires consultation with the appropriate EPA Regional

Offices. Upon concurrence by EPA’s Modeling Clearinghouse, EPA Regional Offices may approve the use of these beta options for regulatory applications as an alte rnative model.
However, Maryland’s a ir dispersion modeling , performed by AECOM, intended to characterize25

air quality as a result of SO 2 emissions from Wagner without prior consultation with and approval from EPA ’s Region 3 ’s Office, and therefore has not m et the applicable regulatory requirements contained in Appendix W, Section 3.2.2. As a result, EPA does not believe that the air quality modeling results obtained from the use of these beta options can be used as a reliable

indicator of attainment status in the area around Wagner until appropriate alternative model approval is granted or these beta options are promulgated as regulatory options in AERMOD through EPA rulemaking. AECOM used AERSURFACE using the location of BWI to estimate the surface characteristics of the Wagner area of analysis. Estimated values for surface roughness used twelve (12 ) spatial sectors out to 1 km at a monthly temporal resolution for dry, wet, average conditions based on

BWI’s 30

- year precipitation averages. AECOM also estimated values for albedo (the fraction of solar energy reflected from the earth back into space) a nd the Bowen ratio (the method generally used to calculate heat lost or heat gained in a substance. No months contained continuous snow cover though there may have been continuous snow cover at BWI in January and February of

2014.

Figure 9 : Met Data Sites used in the Wagner Area of Analysis26

The three

- year (2012

- 14) surface wind rose for Baltimore

- Washington Airport (BWI) based on the processed surface file is depicted in Figure 10 . In this figure, the frequency and magnitude of wind speed and direc tion are defined in terms of where the wind is blowing from. The resultant

vector shows the dominant direction or mean direction of the wind vectors. Winds were predominantly out of the west to northwest.

Figure 10 : Surface Met File Cumulative Wind Rose for Years 2012

- 14

Meteorological data from the surface (BWI) and upper air stations (IAD) were used in generating

AERMOD

- ready files with the AERMET processor. The output meteorological data created by the AERMET processor is suitable for being ap plied with AERMOD input files for AERMOD27

modeling runs. AECOM appears to have generally followed the methodology and settings presented in the processing of the raw meteorological data into an AERMOD

- ready format, and used AERSURFACE to best represent sur face characteristics. There were differences in the AERMOD ready surface and profile files included in AECOM’s documentation; the files included in the AERMOD directory do not match those included in the AERMET_V15181 directory. Notably, the reference me asurement heights in the AERMET_V15181 do not match anemometer heights at BWI.

Hourly surface meteorological data records are read by AERMET, and include all the necessary elements for data processing. However, wind data taken at hourly intervals may not always portray wind conditions for the entire hour, which can be variable in nature. Hourly wind data may also be overly prone to indicate calm conditions, which are not modeled by AERMOD. In order to better represent actual wind conditions at the meteoro logical tower, wind data of one minute duration was provided from the same instrument tower, but in a different formatted file to be processed by a separate preprocessor, AERMINUTE. These data were subsequently integrated into the AERMET processing to prod uce final hourly wind records of AERMOD

ready meteorological data that better estimate actual hourly average conditions and that are less

prone to over

- report calm wind conditions. This allows AERMOD to apply more hours of meteorology to modeled inputs, an d therefore produce a more complete set of concentration estimates. As a guard against excessively high concentrations that could be produced by AERMOD in very light wind conditions, the state set a minimum threshold of 0.5 meters per second in processing meteorological data for use in AERMOD. In setting this threshold, no wind speeds lower than this value would be used for determining concentrations. This threshold was specifically applied to the one minute wind data.

Modeling Parameter: Geography and T errain

Fort Smallwood, Crane, Wheelabrator Baltimore and the proposed Energy Answers facilities are all located along the western shoreline of the Chesapeake Bay. This area is generally characterized as part of the Atlantic Coastal Plain physiographic region. Terrain is generally flat

in the vic inity of the modeled sources but rises steeply approximately 17 kilometers to the northwest of the Fort Smallwood Complex as the Atlantic Coastal Plain gives way to the Piedmont ( see Figure 11 ).28 Figure 11: Elevations in the AECOM modeling domain

Elevation information for stack

- base elevations and model receptors was obtained from National Elevation Dataset (NED) GeoTiff data. GeoTiff is a binary file that includes data descriptors and

geo

- referencing information necessary for extracting terrain elevations. These elevations were

extracted from 1 arc

- second (30 meter) resolution NED files using EPA’s AERMAP processor.

Modeling Parameter: Background Concentrations of SO 2

The Modeling TAD offers two mechanisms for characterizing background concentrations of SO 2 that are ultimately added to the modeled design values: 1) a “first tier” approach, based on monitored design values, or 2) a temporally varying approach, based on the 99 th percentile monitored concentrations by hour of day and seaso n or month. For the Wagner area of analysis, AECOM chose to use an hour of day seasonal varying background concentrations. The background concentration for this area of analysis was determined by AECOM based on hourly

monitored concentrations from the Be ltsville, MD monitoring site. AECOM substituted a constant background concentration of 3.9 μg/m 3 whenever wind directions ranged from 70 to 130 degrees (easterly). This was done to account for a lack of SO 2 sources directly to the east of29

the Wagner area of analysis; 3.9 μg/m 3 was chosen to represent a true pristine background

concentration.

Summary of Modeling Results

The AERMOD modeling parameters for the Wagner area of analysis are summarized below in

Table 15 . Note that AECOM used several non

- defau lt options in their AERMOD analysis. This included using Adjust U* in its AERMET processing and using the non

- default Low Wind 3 option in AERMOD. These options were used in tandem and are not currently considered part of the regulatory default options i n AERMOD. Moreover, Maryland did not seek and has not obtained EPA Regional approval for their use in this case. As a result, EPA does not believe that the air quality modeling results obtained from the use of these beta options can be used as a

reliable indicator of attainment status in the area around Wagner until appropriate alternative model approval is granted or these beta options are promulgated as regulatory options in AERMOD through EPA rulemaking.

Table 15 : AERMOD Modeling Parameters for the Wagner Area of Analysis
Wagner Area of Analysis

AERMOD Version 15181
Dispersion Characteristics Rural

Modeled Sources 4

Modeled Stacks 10

Modeled Structures Multiple, Raven Power Sources Only

Modeled Fencelines 2
Total receptors 6,181
Emissions Type Actual , PTE, Adjusted Actual

Emissions Years Hourly 2012

- 2014, Current PTE, Retro Adjusted Hourly
Meteorology Years 2012

- 2014
Surface Meteorology Station Baltimore

- Washington International Airport, MD
Upper Air Meteorology Station Dulles Airport, Sterling, VA Methodology for Calculating Background SO 2 Concentration Hour to Hour, Seasonally Varying, Easterly Winds changed to “background”

Non

- Default AERMOD Options Adjust U*, Low Wind 3 Calculated Background SO 2 Concentration 10.3 μg/m 3

The results presented below in Table 16 show the magnitude and geographic location of the highest predicted modeled concentration based on emissions compiled by AECOM.30

Table 16: Maximum Predicted 99 th Percentile 1

- Hour SO 2 Concentration in the Wagner Area of Analysis Based on AECOM’s Emis sion Profile

Averaging Period Data Period Receptor Location SO 2 Concentration ( μg/m 3 )

UTM/Latitude UTM/Longitude Modeled (including background) NAAQS

99th Percentile

1

- Hour Average 2012

- 2014 369375 4336940 186.0 196.2* *Equivalent to the 2010 SO 2 NAAQS set at 75 ppb

AECOM’s modeling indicates that the predicted 99 th percentile 1

- hour average concentration within the chosen modeling domain is 186.0 μg/m 3 , or ~71 ppb. This modeled concentration

included the background concentration of SO 2 , and is based on AECOM’s source emission profile. This predicted value occurred approximately 1.1 kilometers east

- southeast of the Fort Smallwood Complex and is graphically represented along with all the other receptors below in Figure s 12

- 13

.

Figure 12: Maxim um Predicted 99 th Percentile 1

- Hour SO 2 Concentrations in the Wagner Area

of Analysis Based on AECOM Emission Profile (Close

- Up)31

Figure 13: Maximum Predicted 99 th Percentile 1

- Hour SO 2 Concentrations in the Wagner Area of Analysis Based on AECOM Emission Profile (Regional)

Detailed Assessment of May 2015 Sierra Club Modeling for Wagner/Brandon Shores/Crane

On January 4, 2016, Sierra Club submitted to EPA an air dispersion modeling analysis of SO 2 from Wagner, Brandon Shores, and Crane. The discussion and analysis that follows below will

reference Sierra Club’s use of the Modeling TAD , EPA’s assessment of Sierra Club’s modeling in accordance with the Modeling TAD, and the factors for evaluation contained in EPA’s March 20, 2015 guidance, as appropriate

Model Selection and Modeling Components

EPA’s d raft Modeling TAD notes that for area designations under the 2010 SO 2 NAAQS, the AERMOD modeling system should be used, unless use of an alternative model can be justified.

In some instances the recommended model may be a model other than AERMOD, such as the BLP model for buoyant line sources. The AERMOD modeling system contains the following

components:

- AERMOD: the dispersion model

- AERMAP: the terrain processor for AERMOD32

- AERMET: the meteor ological data processor for AERMOD

- BPIPPRIME: the building input processor

- AERMINUTE: a pre

- processor to AERMET incorporating 1

- minute automated surface observation system (ASOS) wind data

- AERSURFACE: the surface characteristics processor for AERMET

- AERS CREEN: a screening version of AERMOD

Modeling components used by Sierra Club are summarized in T able 17 . This modeling analysis was completed in May of 2015 so some of the AERMOD components were run using older

versions that were the latest available at the time

. However, EPA does not believe that the use of

the most recent versions of AERMOD and its components would alter the mode led results in a manner that would change our intended designation

. Sierra Club used AERMOD version 14134,

and a discussion of the individual components will be referenced in the corresponding discussion that follows as appropriate. While the version of AERMOD used in Sierra Club’s modeling is not the latest version of the model available, EPA does not believe that updating th e model version and rerunning with the same model inputs and options would result in significantly different modeled impacts or change our intended designation for the area of analysis. EPA conducts tests cases for newly released versions of AERMOD to doc ument the differences in several “standard” test case scenarios to compare results with previous releases of the model. 13
Review of version 15181 test case results and comparison with version 14134 shows that the updated model version impacts modeled resul ts for only a small subset of the test scenarios (capped and horizontal stacks and multiple urban areas), which are not applicable to Wagner. Therefore, we do not anticipate that rerunning the model with the later model version would significantly impact t he modeled concentrations.

No buildings were included in this modeling analysis thus building downwash , which would tend to increase impacts, was not evaluated. AERMOD was run in regulatory default mode.

Ta ble 17 : Model Versions Summary

AERMOD Component Sierra Club Version Current Version

AERMOD 14134 15181

AERSURFACE 13016 13016

AERMAP 11103 11103

AERMET 14134 15181

AERMINUTE 14237 15272

Modeling Parameter: Rural or Urban Dispersion

EPA’s recommended procedure for characterizing an area by prevalent land use is based on evaluating the dispersion environment with in 3 km of the facility. According to EPA’s modeling guidelines, rural dispersion coefficients are to be used in the dispersion modeling analysis if more than 50% of the area within a 3 km radius of the facility is classified as rural. Conversely,

if more than 50% of the area is u rban, urban dispersion coefficients should be used in the

13 AERMOD test case information available at the following website: http://www3.epa.gov/ttn/scram/dispersion_prefrec.htm

.33

modeling analysis. The Sierra Club modeling analysis used rural dispersion coefficients in AERMOD. This was determined by examining the percentage of land use categories within
three (3) kilometer s of the modeled sources. Land use land cover (LULC) information from 1992 was processed using AERSURFACE. Rural categorization was supported based on there being less than 50% of the LULC categories with urban uses surrounding the modeled sources.

Mode ling Parameter: Area of Analysis (Receptor Grid)

EPA believes that a reasonable first step towards characterization of air quality in the Wagner area is to determine the extent of the area of analysis, i.e., receptor grid. Considerations presented in th e Modeling TAD include but are not limited to: the location of the SO 2 emission sources or facilities considered for modeling; the extent of significant concentration gradients of nearby sources; and sufficient receptor coverage and density to adequately capture and resolve the model predicted maximum SO 2 concentrations.

Si erra Club used an extensive model receptor grid that included a total of 97,081 ind ividual receptor grids. A 100

- m spaced Cartesian grid was centered around the Fort Smallwood (Wagner and Brandon Shores generating units) and the Crane facilities. These f acilities are roughly 20 kilometers distant from each other. The model receptor grid spacing was increased to

500 m and extended an additional 10 kilometers from the 100

- m grid. Model receptors extended over the open waters of the Chesapeake Bay and adja cent rivers and also extended over the property boundaries of Fort Smallwood and Crane (these areas would not qualify as ambient air). Sierra Club also used flagpole receptors extending 1.5 m above the surface. EPA generally recommends receptors be locat ed at ground level though this difference in receptor heights should have little impact on final model concentrations.

Figure 14 shows the Sierra Club’s model receptor grid and the locations of the model sources. The approximate property/ambient air boun dary of the Fort Smallwood complex, which includes the Wagner and Brandon Shores generating units

, is also shown. Crane is located approximately

20 kilometers northeast of Fort Smallwood.34 Figure 14 : Sierra Club Model Receptor Grid

Modeling Parameter: Source Characterization

Sierra Club only modeled the coal units for Wagner, Brandon Shores and Crane. A total of six (6) sources were modeled. In addition to the two (2) coal units, Wagner also has two (2) oil fired units, which wer e not included in the modeling analysis. Table 18 lists the largest SO 2 sources from these facilities in EPA’s Clean Air Markets Program 14 database.

Table 18 : Source Listing for Wagner, Brandon Shores (collectively known as Fort Smallwood)

and Crane Facility Unit Fuel SO 2 Control Modeled

H.A. Wagner Unit #1 Oil

- No H.A. Wagner Unit #2 Coal

- Yes H.A. Wagner Unit #3 Coal

- Yes H.A. Wagner Unit #4 Oil

- No

14 http://ampd.epa.gov/ampd/35 Brandon Shores Unit #1 Coal FGD Yes

Brandon Shores Unit #2 Coal FGD Yes

C. P. Crane Unit #1 Coal

- Yes

C. P. Crane Unit #2 Coal

- Yes

Modeling Parameter: Emissions

EPA’s Modeling TAD notes that for the purposes of modeling to characterize air quality for use in designations, the recommended appr oach is to use the most recent three years of actual emissions data and concurrent meteorological data. However, the TAD does provide for the flexibility of using allowable emissions in the form of the most recently permitted, (referred to as PTE or allowable) emissions rate.

EPA believes that continuous emissions monitor ing systems (CEMS) data provide acceptable historical emissions information when it is available, and that these data are available for many electric generating units. I n the absence of CEMS data, EPA’s Modeling TAD highly encourages the use of AERMOD’s hourly varying emissions keyword HOUREMIS, or through the use of AERMOD’s variable emissions factors keyword EMISFACT. When cho osing one of these methods, EPA believes that detailed throughput, operating schedules, a nd emissions information from the impacted source(s) should be used.

In certain instances, states and other interested parties may find that it is more advantageous or simpler to use PTE rates as part of their modeling runs. Specifically, a facilit y may have recently adopted a new federally enforceable emissions limit, been subject to a federally enforceable consent decree, or implemented other federally enforceable mechanisms and control technologies to limit SO 2 emissions to a level that indicates compliance with the NAAQS. The se new limits or conditions may be used in the application of AERMOD. In these cases, the Modeling TAD notes that the existing SO 2 emissions inventories used for permitting or SIP planning demonstrations should contain the necessary emissions information for designations

related modeling. In the event that these short

- term emissions are not readily available, they may be calculated using the methodology in Table 8

- 1 of Appendix W to 40 CFR Part 51 titled,

“Guideline on Air Quality Models.”

The Sierra Club modeling analysis included three (3) emissions scenarios, 1) permitted/maximum allowable emissions, 2) 99 th percentile actual hourly emissions, and 3) actual hourly emissions. Only the simulation that used actual emiss ions from the coal

- fired units at Fort Smallwood (Wagner and Brandon Shores) and Crane are included in our review since

these runs were done in accordance with EPA’s Modeling TAD

.

As noted previously, the modeling analysis did not include SO 2 emissions from two (2) oil

- fired units that are part of Wagner. The coal

- fired units included in the modeling analysis are the largest SO 2 emissions sources in the Baltimore, M aryland area. Other sources in the area are generally below 250 tpy with most well under 100 tpy. The facilities in the area of analysis and

their associated annual actual SO 2 emissions between 2012 and 2014 are summarized in Table

19

.36

Table 19 : 2012

- 14 Actual SO 2 Emissions Sources in the Sierra Club’s Modeling Analysis

Facility Name Unit Designation SO 2 Emissions (tpy )

2012 2013 2014 H.A. Wagner Unit #2 2,512.8 1,551.3 1,939.0
H.A. Wagner Unit #3 4,960.2 8,553.5 7,276.1

Brandon Shores Unit #1 1,546.9 1,389.0 1,669.9

Brandon Shores Unit #2 1,301.3 1,481.3 1,475.2

C. P. Crane Unit #1 1,212.0 831.3 573.4

C. P. Crane Unit #2 961.2 2,140.3 1,313.8

Total Emissions 15,194.4 15,946.7 14,247.2

For each of the six (6) coal units include d in the modeling analysis, Sierra Club used actual hourly emissions from 2012

- 14

. Sierra Club’s hourly emission file was compared to hourly emissions from the Clean Air Markets website and found to be nearly identical. Physical stack parameters including stack heights and stack diameters were checked with information contained

in the 2 011 (Version 1) NEI. Modeled stack heights and diameters nearly matched those contained in the 2011 NEI. Stack temperatures and velocities for the modeled sources were

taken from r ecent stack tests according Sierra Club’s documentation. These values wer e kept constant throughout Sierra Club’s modeling analysis. In reality, both stack temperatures and velocities will vary according to a unit’s load. This information, however, is not readily

available from EPA’s Clean Air Market’s website. The stack tem perature and velocity information in the modeling analysis appears to be reasonable and is similar to values contained

in the 2011 NEI. Sierra Club’s modeled stack parameters and those taken from the 2011 NEI are

summarized in Table s 20 and 21

.

Table 20 : Sierra Club Modeling Stack Parameters

Facility Unit Stack Height (m) Stack

Temperature (K) Stack

Velocity (m/s) Stack

Diameter (m)

Fort Smallwood Brandon Unit 1 121.9 326.5 13.0 9.51

Fort Smallwood Brandon Unit 2 121.9 326.5 12.0 9.51

Fort Smallwood Wagner Unit 2 87.5 409.8 22.7 3.11

Fort Smallwood Wagner Unit 3 105.5 418.7 28.7 4.21

C.P. Crane Crane Stack 1 107.6 427.6 29.9 3.32

C.P. Crane Crane Stack 2 107.6 427.6 29.1 3.3237

Table 21 : EPA 2011 (Version 1) NEI Stack Parameters

Facility Unit Stack Height (m) Stack

Temperature (K) Stack

Velocity (m/s) Stack

Diameter (m)

Fort Smallwood Brandon Unit 1 121.9 325.4 17.0 9.60

Fort Smallwood Brandon Unit 2 121.9 325.4 17.0 9.60

Fort Smallwood Wagner Unit 2 87.5 438.7 30.3 3.11

Fort Smallwood Wagner Unit 3 105.5 430.4 32.4 4.11

C.P. Crane Crane Stack 1 107.6 438.7 30.3 3.32

C.P. Crane Crane Stack 2 107.6 433.2 30.3 3.32

Modeling Parameter: Meteorology and Surface Characteristics

The most recent three years of meteorological data (concurrent with the most recent three years of emissions data) should be used in designations efforts. As noted in the Modeling TAD , the selection of data should be based on spatial and climatological (t emporal) representativeness. The representativeness of the data are based on: 1) the proximity of the meteorological monitoring site to the area under consideration

, 2) the complexity of terrain, 3) the exposure of the meteorological site, and 4) the peri od of time during which data are collected. Sources of meteorological data include National Weather Service (NWS) stations, site

- specific or onsite data, and other sources such as universities, Federal Aviation Administration (FAA), and military stations.

Sierra Club used hourly meteorological data from the Baltimore

- Washington International Airport (BWI). Meteorological data was concurrent with the hourly emission date used in the modeling analysis (2012

- 14). Hourly wind measurements were supplemented with 1

- minute data using EPA’s AERMINUTE processor. Sierra Club did not provide any documentation to determine if the meteorological data is representative of the area surrounding Wagner . BWI is

the closest ASOS first order station and is located a littl e over 10 kilometers west of Fort Smallwood ( see Figure 15 ).

In addition to meteorological variables, AERMET needs surface characteristics to process the meteorological information into the format needed to run in AERMOD. Sierra Club used AERSURFACE to generate surface characteristics based on the location of the B WI anemometer site. The modeled anemometer height (10 meters) was confirmed with available information. Surface characteristics were based on twelve 30o sectors in AERSURFACE and developed on a seasonal basis. Continuous snow cover during the winter sea son and average moisture conditions were assumed for the entire simulation period. A quick check of snow cover information and monthly precipitation values at BWI showed snow cover was only continuous

over the 2014

- 15 winter season and seasonal soil moist ure conditions varied from average to wet to dry in accordance with Section 2.2 of the AERSURFACE user’s guide.38 Figure 15 : Locations of BWI anemometer and Fort Smallwood

The three

- year surface wind rose for the Baltimore

- Washington Airport is depicted in Figure 16

. Winds, based on the AERMET processed data, are predominantly from the west. The resultant

vector shows the dominant direction or mean direction of the wind ve ctors.39 Figure 16 : Baltimore

- Washington Airport Wind Rose for Years 2012

– 2014

Meteorological data from the Baltimore

- Washington Airport, MD and Sterling, VA were used in generating AERMOD

- ready files with the AERMET processor. Output processing files provided by Sierra Club indicate the meteorological data is more than 90% complete using 1

- minute data to supplement the hourly surface wind measurements. Minimum wind speed

thresholds were set to 0.5 m/s as recommended. This approach i s consistent with a March 2013 EPA memo titled, “Use of ASOS meteorological data in AERMOD dispersion Modeling.”40

Modeling Parameter: Geography and Terrain

Fort Smallwood and Crane are both located along the western shoreline of the Chesapeake Bay. This area is generally characterized as part of the Atlantic Coastal Plain physiographic region. Terrain is generally flat in the vicinity of the modeled sources but rises steeply approximately 17

kilometers to the northwest as the Atlantic Coastal Plain gives way to the Piedmont ( see Figure

17 ).

Figure 17 : Elevations in the Sierra Club modeling domain

Elevation information for stack

- base elevations and model receptors was obtained from National Elevation Dataset (NED) GeoTiff data. GeoTiff is a binary file that includes data descriptors and

geo

- referencing information necessary for extracting terrain elevations. These elevations were

extracted from 1 arc

- second (30 meter) resolution NED files using EPA’s AERMAP processor.

Modeling Paramete r: Background Concentrations of SO 2

The Modeling TAD offers two mechanisms for characterizing SO 2 background concentrations that are ultimately added to the modeled design values: 1) a “first tier” approach, based on monitored design values, or 2) a temp orally varying approach, based on the 99 th percentile41

monitored concentrations by hour of day and season or month. Sierra Club chose the first option and used the Prince George County’s Beltsville monitor’s 2011

- 13 design value, which had the

lowest design value of the three (3) monitors in Maryland. Beltsville is located northeast of Washington DC and is over 30 km southwest of Fort Smallwood. The background concentration for the modeling analysis was 26.2 micrograms per cubic meter ( μg/m 3 ), or 10 ppb. 15 This background value was added to the final AERMOD results.

Summary of Modeling Results

Sierra Club’s AERMOD modeling summary for the area surrounding Wagner is summarized

below in Table 22

.

Table 22 : AERMOD Modeling Parameters for the Wagner Area Modeling Analysis Sierra Club’s Wagner Area of Analysis

AERMOD Version 14134
Dispersion Characteristics Rural

Modeled Sources 2

Modeled Stacks 6

Modeled Structures None

Modeled Fencel ines None Total receptors 97,081
Emissions Type Actual Hourly Varying

Emissions Years 2012

- 2014
Meteorology Years 2012

- 2014
Surface Meteorology Station Baltimore

- Washington Airport , MD Upper Air Meteorology Station Sterling, VA Methodology for Calculating Background SO 2

Concentration 2011

- 13 Design Value
Calculated Background SO 2 Concentration 26.2 μg/m 3

The results presented below in Table 23 and Figure 18 show the magnitude and geographic location of the highest predicted modeled concentration based on actual (hourly) emissions.

Table 23 : Maximum Predicted 99th Percentile 1

- Hour SO 2 Concentration in the Wagner Area of Analysis Based on Actual (Hourly) Emissions

Averaging Period Data Period Receptor Location SO 2 Concentration ( μg/m 3 )

UTM/Latitude UTM/Longitude Modeled (including background) NAAQS

99th Percentile

1

- Hour Average 2012

- 2014 368,753.75 4,337,092.5 293.9 196. 2 16

15 The conversion factor for SO 2 (at the standard conditions applied in the ambient SO 2 reference method) is 1ppb = approximately 2.62 μg/m 3

. 16 Equivalent to the 2010 SO 2 NAAQS set at 75 ppb

.42

Sierra Club’s modeling indicates that the predicted 99 th percentile 1

- hour average concentration within the chosen modeling domain is 293.9 μg/m 3 , or approximately 112.3 ppb. This modeled

concentration included a background concentration of SO 2 , and is based on actual (hourly) emissions from six (6) modeled stacks at Fort Smallwood (Wagner and Brandon Shores) and Crane. The peak model concentrati on occurred approximately 500 meters east

- southeast of Fort

Smallwood.

Figure 18 : Maximum Predicted 99 th Percentile 1

- Hour SO 2 Concentrations in the Wagner Area

of Analysis Based on Actual (Hourly) Emissions

Figure 19 shows the locations of all of the model receptors that exceeded the 1

- hour SO 2 NAAQS and elevation information. Violating model receptors are most concentrated within three ( 3 ) km of the Fort Smallwood facility. There are three other areas in the northw estern portion of the model receptor grid that had model receptors that exceeded the NAAQS. These

areas are located over 3 0 km from Fort Smallwood and generally have elevations in the 140 to 190 meter range. Violating model receptors are located in Anne Arundel and Baltimore counties. Sierra Club did not use the MAXDCONT option in their AERMOD analysis so there was no information regarding individual stack contributions to the individual model receptor

violations.43 Figure 19 : V iolating Model Receptors a nd Model Domain Elevations

Modeling Analyses : Summary and Conclusion

Modeling Analysis Summary

EPA received two (2) modeling analyses that included emissions from the Wagner Generating Station in Anne Arundel County, Maryland. This facility is part of Raven Power’s Fort Smallwood complex, which in addition to Wagner includes the Brandon Shores generating facility. The modeling analyses also included emissions from another Raven Power facility, the Crane Generating Station located approximately twent y (20) kilometers northeast of Fort Smallwood in Baltimore County, Maryland.

The first modeling analysis was submitted to EPA by Sierra Club in correspo ndence dated January 4, 2016 . This included a modeling summary that was submitted to the Maryland Depa rtment of the Environment in June of 2015; the modeling report included in this submittal was dated May 4, 2015.

Sierra Club modeled SO 2 emissions from coal

- fired units at Brandon Shores, Wagner and Crane using EPA’s AERMOD dispersion model. Three (3) em issions scenarios were modeled44

including each unit’s maximum allowable (permitted) emission rate, the 99 th percentile hourly emission rate reported to EPA’s Clean Air Market website between 2012 and 2014

, and the actual hourly emission rates reported to EP A’s Clean Air Market website again for 2012

- 14. Only the model simulations using the actual hourly emission rates were considered for attainment designation purposes.

Sierra Club’s modeling analysis utilized an extensive model receptor grid centered on F ort Smallwood and Crane that extended nearly 50 km. This represents the approximate limit of steady

- state Gaussian dispersion models such as AERMOD, as noted in section 6.2.3 (a) of EPA’s Guideline on Air Quality Models (Guideline). While compliant with the Guideline, this receptor grid extends well beyond the recommended area of focus discussed in EPA’s March 1,

2011 clarification memo

. 17 In accordance with EPA’s M odeling TAD, model receptor concentrations should be parsed to exclude any that occurred over open water or in areas otherwise not suitable for siting a physical monitor. Sierra Club ’ s modeling included receptor point s over open water, which were not considered in our analysis. While Sierra Club’s modeling analysis included flagpole receptor s instead of ground receptors, the minimal height of these flagpole receptors (1.5 meters) was not expected to significantly impact final model concentrations. Background concentrations based on the Beltsville, M aryland monitor’s 2011

- 13 design value were added to final modeled concentrations.

Based on the actual hourly emissions, Sierra Club’s maximum modeled 1

- hour SO 2 concentration (in the form of the NAAQS) was 293. 9 μg/m 3 , well above the health

- based standard of 196.2 μg/m 3 . While there may be some minor differences in final modeled concentrations based on Sierra Club’s use of older versions of the AERMOD modeling components, some minor aberrations in meteorological processing steps and minor differences in stack parameters, these factors should not significantly change the final model concentrations.

EPA rece ived a second modeling analysis from Maryland as a supplement to its 2015 designation recommendation on January 15, 2016. AECOM performed the modeling analysis. AECOM was asked by Raven Power to review a previous modeling analysis completed by the Maryland Department of the Environment. AECOM’s modeling analysis also utilized EPA’s AERMOD modeling system to estimate 1

- hour SO 2 concentrations in the vicinities of Fort Smallwood (Brandon Shores and Wagner) along with Crane. This modeling analysis included additional sources that were not part of Sierra Club’s modeling analysis; two (2) oil

- fired units at Wagner along with Wheelabrator Baltimore and the proposed Energy Answers facilities.

AECOM used a hybrid approach compiling the emission inventory used in their modeling analysis. Hourly emissions over 2012

- 14 were used for the majority of Raven Power’s sources included in AECOM’s modeling an alysis. Non

- federally enforceable emission rates wer e used for Wheelabrator Baltimore and the proposed Energy Answers facilities. Actual emissions for Wagner’s coal

- fired Unit 2 were retroactively reduced to 1.0 lbs/MMBtu to reflect a recent fuel switch (April 2015). Mixing emission rates is not in accord ance with EPA’s Modeling TAD.

17 See Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 National Ambient Air Quality Standard and note that while the memo references the 1

- hour NO 2 NAAQS it is equally applicable to the 1

- hour SO 2 standard.45

AECOM’s modeling analysis utilize s an imbedded Cartesian modeling receptor grid on the order of 35 by 35 kilometers centered on the Fort Smallwood and Crane facilities. The number of receptors was much smaller than Sierra Cl ub ’ s and focused on areas approximately 10

kilometers from Raven Power’s sources.

AERMOD processing largely followed standard EPA guidance with two (2) exceptions;

AECOM used non

- default options when it processed its meteorological data via AERMET’s adjus t U* option and utilized the Low Wind 3 processing option in AERMOD itself. EPA does not believe that the air quality modeling results obtained from the use of these beta options can

be used as a reliable indicator of attainment status in the area around Wagner until appropriate alternative model approval is granted or these beta options are promulgated as regulatory options in AERMOD through EPA rulemaking. The modeling report submitted by AECOM includes a published paper that summarizes an evaluation of low

- wind modeling approaches for tall

- stack sources. While seasonally varying hour

- by

- hour background concentrations were added to the final model concentration, AECOM substituted a much lower background concentration (Beltsville, MD) when winds were from an easterly direction.

Final modeled concentrations from AECOM’s modeling analysis were below the 1

- hour SO 2 NAAQS. The peak model concentration was 186.0 μg/m 3 (standard is 196.2 μg/m 3 ).

Modeling Analysis Conclusion to Support Designation

EPA has reviewed the modeling analyses submitted by Sierra Club and AECOM. Both analyses used AEMOD to determine model concentrations near the Wagner generating station in northern Anne Arundel County, MD. Sierra Club’s modeling analysis indicates 1

- h ou r SO 2 concentrations near Wagner exceed the NAAQS. Model violations also occur in portions of Baltimore County. Model receptor violations in Baltimore County are over 10 km from Wagner and are generally beyond the area EPA recommends 1

- hour modeling analyses as the area of focus ( see EPA March 1, 2011 Clarification Memo). Peak modeled concentrations from AECOM’s modeling analysis are significantly lower than Sierra Club’s and are also under the 1

- hour SO 2 NAAQS. Peak model concentrations for Sierra Club and AECOM both occur in the same general area, approximately 1 kilometer east southeast of Wagner (Fort Smallwood) and are shown in Figure 20

.46

Figure 20: Peak Model Concentrations from AECOM and Sierra Club Modeling Analyses

Based on analysi s of both modeling studies, EPA believes that Sierra Club’s modeling analysis most closely follows the guidance outlined in EPA’s modeling TAD and is more representative of actual air quality conditions for the modeled period . While AECOM’s analysis may s uggest lower concentrations due to more recent emission reductions at Wagner’s coal

- fired Unit 2, substituting PTE or non

- federally enforceable lower hourly emission rates retroactively to modify actual emissions does not follow EPA’s modeling TAD, which suggests either using actual emissions from impacting sources or using PTE emission rates (either / or). AECOM’s use of beta options within the AERMOD system may have also contributed to lower model

concentrations. As noted earlier, u pon concur rence by EPA’s Modeling Clearinghouse, EPA Regional Offices may approve the use of these beta options for regulatory applications as an

alternative model. However, Maryland’s a ir dispersion modeling , performed by AECOM, intended to characterize air qualit y as a result of SO 2 emissions from Wagner without prior consultation with and approval from EPA ’s Region 3 ’s Office, and therefore has not met the applicable regulatory requirements contained in Appendix W, Section 3.2.2. As a result, EPA

does not believ e that the air quality modeling results obtained from the use of these beta options47

can be used as a reliable indicator of attainment status in the area around Wagner until appropriate alternative model approval is granted or these beta options are promulg ated as regulatory options in AERMOD through EPA rulemaking.

Given this information, EPA believes the Sierra Club air dispersion modeling provides persuasive evidence that SO 2 NAAQS violations are occurring within Baltimore County and Anne Arundel County, with the maximum concentration in the immediate vicinity of Wagner. In addition, EPA does not believe that AECOM’s modeling provides persuasive evidence that the

area is meet ing the NAAQS based on actual emissions for the period analyzed.

Jurisdictional Boundaries

Maryland’s original 2011 designation recommendation recommended that the entirety of Anne Arundel County be designated as unclassifiable. The State did not provide additional explanation nor analysis and chose to recommend the default county boundary at that time. Maryland’s updated 2015 designation recommendation did not address this factor, and Maryland did not provide a recommended boundary for its recomm ended attainment designation for the Wagner area. Existing jurisdictional boundaries are considered for the purpose of informing our intended designation, specifically with respect to a clearly defined legal boundary once the geographic area associated wi th the immediate area surrounding Wagner , other nearby sources, and background concentration is determined.

There are a limited number of sub

- county jurisdictional boundaries to use if one would want to define attainment boundaries below the county scal es. The State of Maryland has 156 municipal corporations otherwise known as municipalities. Figure 21 shows the municipal units in the Wagner area of analysis. These units, unfortunately, do not create a contiguous entity inside the county boundaries, a nd therefore, do not provide a method for delineating sub

- county nonattainment boundaries in the Wagner area. There are a total of two (2) municipalities in Anne Arundel County and no municipalities that reside totally inside Baltimore County; one municip ality in a neighboring county does extend into Baltimore County.48 Figure 21: Maryland M unicipalities in the Wagner A rea

There are several other possibilities for defining boundaries below the county level in Maryland : US zip codes

, US Census tracts , and council districts . Zip codes were created by the US Postal Service in the 1960s. Zip Codes, unfortunately, are not true linear features but groups of addresses assigned to a single code. Boundaries between individual zip codes are somewhat arbitrary and can be as small as a single mailing address. The US Census defines Census Trac t s to help organize Census information. While these boundaries are sub

- county, they can be quite

small. There are a total of 411 Census trac t s in Anne Arundel and Baltimore counties ( see Figure 22 ). The number of Census trac t s and their relative limited use may make these units

difficult to use to delineate a nonattainment area that would have sub

- county borders.49

Figure 22: 2010 Census Trac t s within Anne Arundel and Baltimore Counties in Maryland

A county council is a legislative body of the county that performs all local governmental functions within its jurisdiction. Both Baltimore and Anne Arundel Count ies are divided into seven (7) co uncil districts (Figure 23). The use of council districts for defining the nonattainment area around Wagner would be difficult in that the violations are spread across numerous districts, forming a non

- contiguous area. Furthermore, because o f where the modeled violations are located across Baltimore County in relation to Baltimore County’s council district boundaries, large areas spanning northward towards Pennsylvania would be included that are likely not being impacted by Wagner’s SO 2 emiss ions.50

Figure 23: Council Districts within Anne Arundel and Baltimore Counties in Maryland

Given that existing jurisdictional boundaries do not appear suitable for defining the nonattainment area surrounding Wagner, EPA believes that another alternative to using jurisdictional boundaries is to draw a circle around the source and all modeled violating receptors. Such a circle would be drawn with Wagner’s Unit 3 stack as the center ( located at 39.17765N latitude, 76.52752W longitude ) with a rad ius extending out 35.5 kilometers in order to capture all the violating receptors both with in Anne Arundel and Baltimore Counties. Those portions of Anne Arundel and Baltimore Counties residing within this circle would encompass

the nonattainment area. F urthermore, i n the absence of information from Maryland concerning jurisdictional boundaries, EPA believes that our intended nonattainment area, consisting of portions of Anne Arundel County and Baltimore County, is comprised of a clearly defined legal

bou ndary, and we find this boundary to be a suitably clear basis for defining our intended

nonattainment area. There are no previously designated nonattainment areas in the nearby vicinity of Wagner whose boundaries could have been considered in this case. The area around Wagner would be nonattainment based on available modeling information regarding elevated

SO 2 levels within Anne Arundel and Baltimore Counties, emissions data, emission control information, as well as wind patterns and terrain . See the “Ai r Dispersion Modeling” section for51

the assessment of air dispersion modeling provided by Sierra Club. In contrast, this information also shows that the jurisdictional area of Baltimore City does not have elevated SO 2 levels.

Other Relevant Information

On January 13, 2016, Sierra Club submitted a follow

- up to their January 4, 2016 modeling

submission. In that submission, Sierra Club notes that Maryland’s 2015 designation recommendation includes ambient air monitoring data from a two

- month study that sho ws the

occurrence of a maximum 1

- hour SO 2 concentration of 101.7 ppb at a monitor closest to Wagner, which far exceeds the SO 2 NAAQS

. Additionally, Sierra Club’s submission included a presentation Maryland gave to stakeholders in February 2014, in which M aryland summarizes the results of its own and Sierra Club’s prior modeling and explains the unit

- specific emission rates necessary to ensure compliance with the 1

- hour SO 2 NAAQS. Sierra Club also included a

draft SO 2 regulation Maryland had previously rel eased to stakeholders that included proposed

emission rates for sources. Sierra Club explains that the monitoring data provided by the State is not supportive of an attainment designation, and also urg es EPA to carefully review any newly proposed emission limits from Maryland that may differ from those previously identified by Maryland in the draft SO 2 regulation. Under the “Air Quality Data” section in this draft technical support document, EPA acknowledges that the monitoring data from the two

- month study Maryland submitted is not supportive of an attainment designation. EPA is unabl e to comment on any previously proposed SO 2 emission limits released in a draft regulation by Maryland as that would have been a work

- in

- progress and based on modeling th at would have been done prior to EPA’s Modeling TAD being released.

On January 20, 2016, Sierra Club submitted further information with regards to Maryland’s January 15, 2016 recommendation supplement. Their submission notes that Maryland’s January 15 , 2016 modeling analysis neither utilized actual historical emission data, nor

maximum SO 2 emissions, and inappropriately utilized options not formally approved under Appendix W, and assert that this analysis fails to support an attainment or unclassifiabl e desi gn ation. EPA’s analysis of Maryland’s modeling analysis is discussed in detail under the section entitled “Air Dispersion Modeling” in this draft technical support document

.

Detailed Assessment for Baltimore City Area

Air Dispersion Modeling

A vailable air dispersion modeling shows persuasive evidence that violations of the SO 2 NAAQS are not occurring within Baltimore City. See the “Air Dispersion Modeling” section for EPA’s

detailed review of the analyses

.

Air Quality Data

This factor considers the SO 2 air quality monitoring data ; however, there are no ambient air quality monitors located in Baltimore City , and Maryland’s 2011 designation recommendation did not address this factor. The closest ambient air quality monitor to Baltimore C ity is located52

east of Baltimore City in neighboring Baltimore County. The monitor’s 2012

- 2014 design value is 22 ppb ( see Tables 2 and 3) , well below the SO 2 standard

.

Emissions and Emissions

- Related Data

Maryland’s 2011 designation recommendatio n did not address this factor. EPA’s review of emissions information shows that there are no large SO 2

- emitting sources located within Baltimore City that could be contributing to elevated levels of SO 2 concentrations. The largest

source in Baltimore Cit y is Wheelabrator Baltimore L.P. with 2013 NEI SO 2 emissions of 321

tpy and 2011 NEI SO 2 emissions of 261 tpy ( see Table 6) ; this facility is located approximately 3 km from the city border

.

Tr aditionally, a source ’ s modeled impact would be compared to the Significant Impact Level (SIL) to gauge if it is significantly impacting a modeled violation. This information, unfortunately, is not readily available from either Sierra Club’s or AECOM’s modeling analys e s. Sierra Club did not include sources inside Baltimore City in its analysis

, nor did it provide a culpability analysis of its modeled violations using the MAXDCONT function in AERMOD. While AECOM did include sources inside Baltimore City (Wheelabrator Baltimore and the proposed Energy Answers facil ity) they did not run MAXDCONT since there were no modeled

violations in its analysis (MAXDCONT only works for receptors over the NAAQS).

In light of these deficiencies, EPA attempted to gauge Wheelabrator Baltimore’s impact on Sierra Club’s violating rec eptors using AECOM ’s modeling for its peak receptor and SCREEN3 modeling to determine if modeled concentrations would exceed the interim 1

- hr SO 2 SIL (7.8 μg/m 3 )

.

Table 4

- 3 in AECOM’s modeling report lists the contributions from each source towards it s peak

modeled concentration . For all other sources, excluding Brandon Shores, Wagner and Crane, the total other sources category model concentration (Wheelabrator Baltimore and Energy Answers) was 1.4 μg/m 3 , approximately 0.7% of the NAAQS. This indicates impacts from Wheelabrator

Baltimore are below the 1

- hr SO 2 SIL for receptors immediately downwind of Wagner . Based on this information, Wheelabrator Baltimore is not significantly contributing to (Sierra Club’s)

modeled violations surrounding Wagner

.

Si erra Club modeling also had violating receptors in several other areas of Baltimore County.

EPA ran SCREEN 3 to gauge if emissions from Wheelabrator Baltimore could significantly contribute to these modeled violations. Figure 24 shows the locations of the violating receptors, significant emission sources in the Baltimore area and the approximate centerlines between Wagner Unit 3 and three (3) groups of violating receptors in Baltimore County and the Sierra Club peak receptor

. C e nterlines are lines drawn from an emission point to the receptor. A straight

- line dispersion model calculates the maximum concentration along this centerline.

Model concentrations will “fall off” laterally along the normal line drawn to the centerline

fo llowing some type of Gaussian distribution. Based on the figure, Wheelabrator Baltimore generally falls off of the centerline from Wagner Unit 3 (except for the centerline drawn for the Sierra Club peak receptor).53 Figure 24: Centerlines for various sou rces and modeled violating receptors

EP A ran SCREEN3 using emissions from Wheelabrator Baltimore for different receptors representing downwind receptors from Wagner (including Sierra Club’s peak receptor) along with roughly three (3) groups of violating receptors based on the Sierra Club modeling. Model

results are available as an appendix.

An emission rate of 1.0 grams/second ( g/s ) was used in SCREEN3. Concentrations can then be scaled according to Wheelabrator Baltimore’s 2012

- 14 actual emissions; Energy Answers was omitted from the analysis since it had no actual emissions between 2012

- 14

. Table 2 5

summarizes SCREEN3 results.

Table 24: Wheelabrator Baltimore 2012

- 14 Actual Emissions

Year tpy g/s

2012 194 5.56548

2013 321 9.23409 2014 (Preliminary) 310 8.9176654

Table 25: Wheelabrator Baltimore Emissions and SCREEN3 Model Results Receptor Terrain

Type 1

- hr Model

( μg/m 3 /1.0 g/s) 24

- hr Model

( μg/m 3 /1.0 g/s) 18 Adjusted

2012 ( μg/m 3 ) Adjusted

2013 ( μg/m 3 ) Adjusted

2014 ( μg/m 3 )

F ort Smallwood

Peak Simple 0.481

- 2.68 4.44 4.29

Sierra Club Peak Simple 0.4793

- 2.67 4.43 4.27 West Violating

Rec eptors Complex

- 0.3646 8.12 13.47 13.01

North Violating

Rec eptors Complex

- 0.2123 4.73 7.84 7.57

NW Violating

Rec eptors Complex

- 0.1518 3.38 5.61 5.41

SCREEN3 results indicate the only receptors where Wheelabrator Baltimore’s contributions could potentially exceed the 1

- hr SO 2 SIL is the group of receptors in western Baltimore County (due west of Wheelabrator Baltimore). SCREEN3 values for the West Receptors are approximately 7% of the NAAQS , which is over the interim 1

- hr SO 2 4% SIL. It should be

noted that the SCREEN3 result is the maximum concentration for the centerline extending between this group of receptors and Wheelabrator Baltimore and not the centerline drawn between Wagner Unit 3 and the West Receptors . In fact , only the edge of Wheelabrator Baltimore’s plume based on the Wagner Unit 3

- West Receptor centerline would impact these

receptors

, thus yielding a lo wer concentration than SCREEN3 would predict. Given that the violating receptors ’ peak 99 th percentile concentrations are occurring during stable overnight hours, the lateral spread along the centerline for Wheelabrator Baltimore is probably not large enough to extend over these receptors; Wheelabrator Baltimore’s plume would have to laterally spread nearly 5 km from the Wagner Unit 3

- West Receptor centerline to impact these receptors

. Further evidence of SCREEN3 overes timation is seen in the Sierra Club peak receptor

concentrations . Based on AECOM’s analysis, Wheel a brator Baltimore ’s modeled impact is less than 1% of the NAAQS at its peak model receptor. Since both the Sierra Club and AECOM peak receptors are nearly i n the same place , AECOM’s results indicate SCREEN3 is overestimating Wheelabrator Baltimore’s model impacts by nearly a factor of three (3); 1.4 μg/m 3 versus 4.43 μg/m 3

. Using this adjustment, Wheelabrator Baltimore’s model contributi on to the West Recept ors is most likely under the interim 1

- hr SO 2 SIL.

Due to its low emissions , and based on all available information, EPA finds it unlikely that any sources within Baltimore City have the potential to cause or contribute to a violation of the NAAQS within the city. Furthermore, a vailable modeling analyses further provide evidence that large SO 2 sources located outside of Baltimore City are likewise not impacting SO 2 levels within Baltimore City.

18 24

- hr concentration based on Valley model. Concentrations divided by 0.25 to get 1

- hr concentrations in

accordance with section 3.8 of SCREEN3 User’s Guide.55

Meteorology (Weather & Transport Patterns)

Maryland’s 2011 designation recommendation did not address meteorology . EPA’s review of meteorology shows that t he closest hourly reporting meteorological monitoring station to Baltimore City is the Baltimore

- Washington International Airpor t , located southwest of Baltimore City . A wind rose for the 2 012

- 14 time period ( see Figure 4 ) shows predominantly westerly winds in the area. Availa ble modeling analyses provide evidence that westerly wind s do not contribute to elevated levels of SO 2 within Baltimore City from large SO 2 sources located outside of Baltimore City. Likewise, based on S CREEN 3 results and our analysis and comparison to AECOM’s and Sierra Club’s analyses discussed under the “Emissions and

Emissions

- Related” section, EPA believes there is persuasive evidence indicating that emissions from within Baltimore City are not impacting SO 2 levels in area s outside of Baltimore City that are not meeting the NAAQS

.

Geography and Topography (Mountain Ranges or Other Air Basin Boundaries)

Maryland’s 2011 designation recommendation did not a ddress this factor. EPA has reviewed both the geography and topography of Baltimore City. Baltimore City lies west of the Chesapeake Bay with the southern half lying within the coastal plain and the nor th/northwest

corner within the Piedmont plateau ( see Figure 6)

. Given that there is limited terrain in this area, topography would likely not contribute to elevated concentrations of SO 2 in Baltimore City. Available modeling analyses provide evidence tha t the terrain located in the north/northwest of the city do es not impact SO 2 concentrations within Baltimore City.

Jurisdictional Boundaries

Maryland’s 2011 designation recommendation recommended that the entirety of Baltimore City be designated as unclassifiable. The State did not provide additional explanation nor analysis and chose to recommend the default city boundary at that time. E xisting jurisdictional boundaries are considered for the purpose of informing our intended designation , specific ally with respect to a cl early defined legal boundary. EPA’s review of available air dispersion modeling shows persuasive evidence that elevated SO 2 levels are not occurring within Baltim ore City. Therefore, EPA believes that our intended unclassifiable/ attainment designation for Baltimore City is comprised of a n appropriate and clearly defined legal boundar y.

Conclusion for the Anne Arundel County and Baltimore County and Baltimore City Areas

After careful evaluation of the S tate’s 2011 and 2015 updated recommendation s and additional information including SO 2 emissions, air quality monitoring, air dispersion modeling results

, meteorology, geography and topography

, EPA intends to designate the area around the Herbert A. Wagner Generat ing Station as nonattainment for the 2010 SO 2 NAAQS. Specifically, EPA

intends to include portions of Anne Arundel County and Balt imore County in the nonattainment

area that are within 35.5 kilometers of Herbert A. Wagner’s Unit 3 stack, which is located at 39.17765N latitude, 76.52752W longitude

. Sierra Club’s January 4, 2016 air dispersion modeling

, which included actual SO 2 emissions data from Wagner, provides persuasive evidence56

that SO 2 NAAQS violations are occurring within Baltimore County and Anne Arundel County, with the maximum concentration in the immediate vicinity of Wagner. The modeling also shows

that violations may be occurring in several locations northwest and west of the Facility in neighboring Baltimore County over 3 0 kilometers a way from the Facility. In contrast, Maryland’s submitted January 2016 modeling analysis is problematic, not in accordance with EPA’s Modeling TAD or Appendix W , and does not support an attainment designation given

that the Si erra Club modeling demonstrates violations

. Given these air dispersion modeling results, emissions data, lack of federally enforceable SO 2 emission controls at Wagner and

Crane

, as well as general wind patterns and topography, EPA finds it reasonable that the area

surroundi ng Wagner be designated as nonattainment , and as such intends to designate portions of Anne Arundel County and Baltimore Coun ty as nonattainment for the 2010 SO 2 NAAQS. Specifically, those p ortions of Anne Arundel and Baltimore Counties that are within 35.5 kilometers of Wagner’s Unit 3 stack, which is located at 39.17765N latitude, 76.52752W longitude , would be designated as nonattainment.

Additionally, Sierra Club’s air dispersion modeling shows persuasive evidence that violations are not occurring in Baltimore City . Given these modeling results and that there are no large SO 2 emissions sources located within Baltimore City that could be impacting areas outside of Baltimore City

, as well as no violating monitors in the area and limited terrain, E PA believes there is persuasive evidence to support a conclusion that Baltimore City is meeting the NAAQS

and that a designation of unclassifiable/attainment is appropriate . T herefore, EPA intends to designate Baltimore C ity as unclassifiable/attainment for the 2010 SO 2 NAAQS.

At this time, our intended designation for the state only appl ies to the area presented in this technical support document. Consistent with the conditions in the Ma rch 2, 2015 consent decree

and the court order

, EPA will evaluate and designate all remainin g undesignated areas in Maryland by either December 31, 2017 or December 31, 2020.57 APPENDIX: SCREEN3 MODEL RESULTS

02/08/16

12:00:14

*** SCREEN3 MODEL RUN ***

*** VERSION DATED 13043 ***

WheelabratorMD_Screen3

COMPLEX TERRAIN INPUTS:

SOURCE TYPE = POINT

EMISSION RATE (G/S) = 1.000000

STACK HT (M) = 96.0100

STACK DIAMETER (M) = 2.1300

STACK VELOCITY (M/S) = 22.5500

STACK GAS TEMP (K) = 485.9300

AMBIENT AIR TEMP (K) = 287.8000

RECEPTOR HEIGHT (M) = 0.0000

URBAN/RURAL OPTION = RURAL

THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED.

THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTER ED.

BUOY. FLUX = 102.264 M**4/S**3; MOM. FLUX = 341.593 M**4/S**2.

FINAL STABLE PLUME HEIGHT (M) = 180.558

DISTANCE TO FINAL RISE (M) = 150.0

*VALLEY 24

- HR CALCS* **SIMPLE TERRAIN 24

- HR CALCS**

TERR MAX 2 4

- HR PLUME HT PLUME HT

HT DIST CONC CONC ABOVE STK CONC ABOVE STK U10M USTK

(M) (M) (UG/M**3) (UG/M**3) BASE (M) (UG/M**3) HGT (M) SC (M/S)

----- ------- ---------- ---------- ------ ---------- ------ -- ---- ----

154. 9460. 0.9060 0.3646 180.5 0.9060 75.7 6 1.0 3.5

148. 14040. 0.7316 0.2123 180.5 0.7316 75.7 6 1.0 3.5

195. 20290. 0.1518 0.1518 180.5 0.000 0.0 0 0.0 0.0

02/08/16

12:00:14

*** SCREEN3 MODEL RUN ***

*** VERSION DATED 13043 ***

WheelabratorMD_Screen3

SIMPLE TERRAIN INPUTS:

SOURCE TYPE = POINT

EMISSION RATE (G/S) = 1.000000

STACK HEIGH T (M) = 96.0100

STK INSIDE DIAM (M) = 2.1300

STK EXIT VELOCITY (M/S)= 22.5500

STK GAS EXIT TEMP (K) = 485.9300

AMBIENT AIR TEMP (K) = 287.8000

RECEPTOR HEIGHT (M) = 0.0000

URBAN/RURAL OPT ION = RURAL

BUILDING HEIGHT (M) = 0.0000

MIN HORIZ BLDG DIM (M) = 0.000059

MAX HORIZ BLDG DIM (M) = 0.0000

THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED.

THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT O F 10.0 METERS WAS ENTERED.

BUOY. FLUX = 102.264 M**4/S**3; MOM. FLUX = 341.593 M**4/S**2.

*** FULL METEOROLOGY ***

*********************************

*** SCREEN DISCRETE DISTANCES ***

*********************************

*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***

DIST CONC U10M USTK MIX HT PLUME SIGMA SIGMA

(M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) Y (M) Z (M) DWASH

------- ---------- ---- ----- ----- ------ ------ ------ ------ -----

13980. 0.4810 3 1.0 1.3 592.9 591.94 1113.08 697.00 NO

14040. 0.4793 3 1.0 1.3 592.9 591.94 1117.24 699.63 NO

DWASH= MEANS NO CALC MADE (CONC = 0.0)

DWASH=NO MEANS NO BUILDING DOWNWASH USED

DWASH=HS MEANS HUBER

- SNYDER DOWNWASH USED

DWASH=SS MEANS SCHULMAN

- SCIRE DOWNWASH USED

DWASH=NA MEANS DOWNWASH NOT APPLICABLE, X<3*LB

***************************************60

*** SUMMARY OF SCREEN MODEL RESULTS ***

***************************************

CALCULATION MAX CONC DIST TO TERRAIN

PROCEDURE (UG/M**3) MAX (M) HT (M)

-------------- ----------- --------- -------

SIMPLE TERRAIN 0.4810 13980. 0.

COMPLEX TERRAIN 0.9060 9460. 154. (24

- HR CONC)

***************************************************

** REMEMBER TO INCLUDE BACKGROUND CONCENTRATIONS **

***************************************************