UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION III

1650 Arch Street

Philadelphia, Pennsylvania 19103-2029

SUBJECT: Technical Support Document for Approval 

and Promulgation of Air Quality 

Implementation Plans; District of Columbia, 

Maryland and Virginia; Attainment 

Demonstration for the 1997 8-Hour Ozone 

National Ambient Air Quality Standard for 

the Washington, DC-MD-VA Moderate 

Nonattainment Area (Docket ID#: EPA-R03-

OAR-2013-0132).

February 26, 2013

FROM: Christopher Cripps /s/

Environmental Engineer (3AP30)

TO: Docket ID#: EPA-R03-OAR-2013-0132

THRU: Cristina Fernandez /s/

Associate Director, 

Office of Air Program Planning 

This technical support document (TSD)1is EPA's evaluation of the following District of 

Columbia, State of Maryland and Commonwealth of Virginia State Implementation Plan (SIP) 

revision submittals for the Washington, D.C. ozone nonattainment area (“Washington, DC area” 

or “Washington Area”) to determine whether these can be approved as SIP revisions: 

Attainment Demonstration for the and Contingency Measures for Failure to Attain the 1997 

Ozone National Ambient Air Quality Standards (NAAQS) (hereafter “the 1997 ozone 

NAAQS”).

I. Background & Scope

A. Scope

The District of Columbia, the State of Maryland and the Commonwealth of Virginia (hereafter 

“the 3 States” ) submitted attainment and reasonable further progress (RFP) plan SIP revisions to 

EPA on June 12, 2007, June 4, 2007 and June 12, 2007, respectively (hereafter “the June 2007 

SIP revisions”). Hereafter the term the “3 States” shall mean the District of Columbia, Maryland 

and Virginia collectively. 

These June 2007 SIP revisions included, among other things, the attainment plan and failure-toattain contingency measures elements for the 1997 ozone NAAQS in the Washington Area. The 

ozone attainment plan submitted on the June 2007 SIP revisions each included the attainment 

 

1 This document is called the “Attainment TSD” in the notice of proposed rulemaking for which this document was 

prepared. 
demonstration and contingency measures for failure to attain for the Washington Area plus the 

associated 2009 and 2010 motor vehicle emission budgets (MVEBs) used for transportation 

conformity purposes in the entire Washington Area. The June 2007 SIP revisions also included a 

2002 base year emissions inventory, an analysis of the reasonably available control 

measures/reasonably available control technology (RACM/RACT), the 2008 reasonable further 

progress (RFP) plan and its associated MVEBs for 2008, and contingency measures. The other 

elements – including the RFP plan with 2008 MVEBs, a RACM/RACT analysis, the 2002 base 

year emissions inventory, and contingency measures for any failure to make RFP – in the June 

2007 SIP revisions were approved by EPA on September 20, 2011 (76 FR 58116) (the 

“September 20, 2011 final rule”). Therefore, in this action, EPA is only proposing to approve 

the attainment demonstration for the 1997 ozone NAAQS for the Washington Area. 

Specifically, this technical support document (TSD) is EPA's evaluation of only those portions of 

the June 2007 SIP revisions pertaining to the attainment demonstration and contingency 

measures for failure to attain the 1997 ozone NAAQS. As will be discussed in a subsequent 

paragraph of this TSD, EPA has approved other plan elements in these June 2007 SIP revisions 

and has made other determinations regarding the Washington Area and these June 2007 SIP 

revisions via separate rulemaking final actions and separate notices.

B. Background on the 1997 Ozone NAAQS and Designation of the Washington Area

On July 18, 1997 (62 FR 38856), EPA promulgated the 1997 ozone NAAQS which revised the 

health-based NAAQS for ozone by setting the NAAQS at 0.08 parts per million (ppm) averaged 

over an 8-hour time frame.2 EPA set the 1997 ozone NAAQS based on scientific evidence 

demonstrating that ozone causes adverse health effects at lower ozone concentrations and over 

longer periods of time than was understood when the pre-existing 1-hour ozone standard was set. 

EPA determined that the 1997 ozone NAAQS would be more protective of human health, 

especially for children and adults who are active outdoors, and individuals with a pre-existing 

respiratory disease, such as asthma.

On April 30, 2004 (69 FR 23951), EPA finalized the attainment/nonattainment designations for 

areas across the country with respect to the 1997 ozone NAAQS. These actions became 

effective on June 15, 2004. Among those nonattainment areas was the Washington Area.

The Washington Area is comprised of: the entire District of Columbia (the District), a portion of 

Maryland (Calvert, Charles, Frederick, Montgomery, and Prince George’s Counties); and a 

portion of Virginia (Alexandria City, Arlington County, Fairfax City, Fairfax County, Falls 

Church City, Manassas and Manassas Park Cities, and Prince William County). All of the 

nonattainment area for the 1997 ozone NAAQS was part of the severe ozone nonattainment area 

for the 1-hour ozone NAAQS prior to June 15, 2005 the date the 1-hour ozone NAAQS was 

revoked. Because the Washington Area was part of an area designated nonattainment for and 

classified as severe under the 1-hour ozone NAAQS, the 3 States have already satisfied certain 

moderate area requirements and were required to keep in place those “applicable requirements” 

defined by 40 CFR 51.900(f) to prevent “antibacksliding” under applicable portion of the 

implementation rule (40 CFR 51.905(a)) for the 1997 ozone NAAQS. As a result, the 3 States 

already had implemented in their respective SIP some of the requirements for areas classified as 

moderate nonattainment for the 1997 ozone NAAQS. 

 

2 Due to rounding conventions this standard requires a value of 0.085 ppm or higher for the NAAQS to be violated. 

One part per billion (ppb) is equal to one one-thousandth (0.001) ppm. Thus the effective standard of the 1997 

ozone NAAQS is 84 ppb.
In addition, on April 30, 2004 (69 FR 23951), EPA promulgated its “Phase 1 Implementation 

Rule” which provided how areas designated nonattainment for the 1997 ozone NAAQS would 

be classified using the design value for each nonattainment area. Based upon its design value for 

the three-year period 2001-2003, the Washington Area was classified as a moderate ozone 

nonattainment area under the 1997 ozone NAAQS. See, 40 CFR 81.309, 81.321, and 81.347. 

Moderate areas are required to attain the 1997 ozone NAAQS by no later than six years after 

designation. Therefore, the Washington Area was to attain by no later than June 15, 2010. See 

40 CFR 51.903 and 69 FR 23951 (April 30, 2004). 

B. Air Quality Planning Agencies

Air quality planning for the Washington, DC ozone nonattainment area is done jointly by the 

District of Columbia, Maryland, Virginia and the Metropolitan Washington Air Quality 

Committee (MWAQC). The MWAQC is composed of state and local elected officials, state air 

quality and transportation planning directors and the chair of the National Capital Region 

Transportation Planning Board. The Governors of Maryland and Virginia and the Mayor of the 

District of Columbia have certified the MWAQC as the air quality planning organization for the 

Washington, DC ozone nonattainment area under section 174 of the CAA. The MWAQC 

ensures interstate air quality planning consultation requirements of sections 182(j) and 174 are 

fulfilled and that the conformity budgets in the Washington, DC attainment demonstration meet 

the consultation procedures of the transportation conformity rules.

The MWAQC with the assistance of the local municipal planning organization, the Metropolitan

Washington Council of Governments (MWCOG), Virginia, Maryland and the District, 

developed a single plan for the entire nonattainment area. The MWAQC recommends air quality 

planning measures and reviews attainment demonstrations (and ROP plans) which the states 

adopt as SIP revisions. The MWAQC relies upon the three air planning agencies, the Maryland 

Department of the Environment (MDE), Virginia Department of Environmental Quality (DEQ), 

and the District of Columbia's, Department of the Environment, and upon the MWCOG for 

technical support. Each jurisdiction adopts the MWAQC-approved plan as a revision to its SIP. 

This document details EPA's evaluation of the District’s, Maryland's and Virginia’s February 

2004 SIP revisions.

C. General Guidelines

To perform this evaluation, EPA has referred to the requirements of sections 172 and 182 of the

CAA, to the “General Preamble for the Implementation of Title I of the Clean Air Act

Amendments of 1990” (the General Preamble) (57 FR 13498, April 16, 1992), to EPA’s rules 

codified at 40 CFR Part 51, Subpart X “Provisions for Implementation of 8-Hour Ozone 

National Ambient Air Quality Standard,” which translates the CAA for implementation of the 

1997 ozone NAAQS, the final rule preambles associated with this implementation rule (the 

“Phase 1 Rule” 69 FR 23951, April 30, 2004 and the “Phase 2 Rule” 70 FR 71612, November 29 

,2005) and EPA’s guidance documents and memoranda that specifically address attainment 

demonstrations.
II. What are the CAA Requirements for a Moderate 8-Hour Ozone Nonattainment Area?

A. Moderate Area Requirements

Pursuant to the Phase 1 Implementation Rule, an area was classified under subpart 2 of Title I of 

the CAA based on its 8-hour design value if it had a 1-hour design value at or above 0.12 ppm. 

Based on this criterion, the Washington Area was classified under subpart 2 as a moderate 

nonattainment area. The Phase 2 Implementation Rule addressed the control obligations that 

apply to areas classified under subpart 2. Among other things, the Phase 1 and 2 Implementation 

Rules outline the required SIP elements and deadlines for those various requirements in areas 

designated as moderate nonattainment.

On November 29, 2005 (70 FR 71612) EPA promulgated the second phase (Phase 2) of the 

implementation rule (Phase 2 Implementation Rule) for the 1997 ozone NAAQS. The Phase 2 

Implementation Rule set forth the submission deadlines and substantive requirements for the 

attainment demonstration, contingency measures and RFP requirements of sections 172(c) as 

supplemented by section 182(b) of the CAA. The requirements regarding a demonstration of 

attainment of the 1997 ozone NAAQS are:

(1) a demonstration that the SIP contains enough reductions of volatile organic compound 

(VOC) emissions and of nitrogen oxides (NOx) emissions to attain the 1997 ozone NAAQS as 

expeditiously as practicable but no later than June 15, 2010 (section 172(c)(1) as amended by 

section 182(b)(1) as codified in 40 CFR 51.908). However, because compliance with the 1997 

ozone NAAQS must be determined using three years of complete, quality assured air quality 

monitoring data, any determination of attainment by June 15, 2010 would have to be made upon 

the most recent three years of air quality monitoring data available which would be 2007, 2008 

and 2009. For this reason, the Phase 1 rule (40 CFR 51.908) required that the emission reduction 

measures need to be implemented no later than the beginning of the 2009 ozone season and that 

the MVEBS for the attainment demonstration be for 2009. As a result, the modeling 

demonstration would need to use projected 2009 emissions inventories reflecting the control 

strategies and predict 2009 design values;

(2) a demonstration that the SIP provides for the implementation of all reasonably 

available control measures (RACM) (including at a minimum reasonably available control 

technology (RACT) on existing sources) (section 172(c)(1)) which includes two elements: 

(a) Under section 172(c)(1) RACM/RACT, a state must “consider all potentially 

available measures to determine whether they [a]re reasonably available for implementation in 

the area, and whether they would advance the [area's] attainment date." See, for example, 66 FR 

585 at 608, January 3, 2001;3and

(b) CAA section 182(b)(2) sets a requirement for RACT not related to expeditious 

attainment but requires a f adopt rules for any category of VOC sources for which EPA has 

issued a control technique guideline (CTG) and for any other major stationary sources of VOC 

emissions in the area. Section 182(f) extends the requirement for RACT under section 

182(b)(2)(C) to any major stationary sources of NOx emissions in the area.4 

 

3 The United States Courts of Appeals for the District of Columbia Circuit upheld this definition of RACM (but did 

remand the SIP at issue to the EPA to determine which measures, if any, are RACM to be implemented by the States 

for the area at issue in that case). See, 70 FR 6798, February 3, 2005, citing Sierra Club v. Whitman, 294 F.3d 155, 

162-163 (DC Cir. 2002). 

4 A State can seek relief from, that is, seek a “waiver” of this requirement if the State can make the requisite 

demonstration specified in CAA section 182(f); the “waiver” provisions in section 182(f) are not applicable for the 

Washington Area. 
(3) a demonstration that the SIP demonstrates a minimum RFP towards attainment by 

reducing baseline emissions of VOC and/or NOx by 15 percent before December 31, 2008 

(section 172(c)(2) as amended by section 182(b)(1)(A) and by 70 FR 71612 at 71634-71637, 

November 29, 2005, which is codified at 40 CFR 51.910) and contains adequate MVEBS for 

2008;

5

(4) a 2002 baseline inventory from which the 15 percent reduction in baseline emissions 

is to be determined (sections 172(c)(3) and 182(b)(1)(B) as interpreted by 70 FR 71612 at 

71637-71638, November 29, 2005 codified at 40 CFR 51.910(d)); and, 

(5) specific measures to be undertaken if the area fails to: (a) attain the 1997 ozone 

NAAQS by June 15, 2010, or (b) fails to achieve RFP (section 179(c)(9)). 

(6) adequate MVEBs:

6

 In the case of moderate nonattainment areas under the 1997 

NAAQS, RFP plans and attainment demonstrations must contain adequate MVEBs for 2008 and 

2009, respectively, and in the June 2007 SIP revisions the 3 States also included a 2010 MVEB 

for NOx as part of the contingency plan to address a failure to attain.

In addition to the above sections 172(c) and 182(b) requirements, the 3 States would be required 

to incorporate into each SIP regulations to implement the following: 

(7) a vehicle inspection and maintenance (I/M) program (CAA section 182(b)(4); 

(8) a “Stage II” vehicle refueling vapor recovery program (CAA section 182(b)(3));

7

and 

(9) an emissions statement program (CAA section 182(a)(3)(B)). 

Items (7) through (9) above can be considered as “anti-backsliding elements.”

B. How have the 3 States Fulfilled the Requirements Applicable in Moderate 

Nonattainment Areas? 

1. Certain Anti-backsliding Elements

Regarding items (7) through (9) inclusive EPA has already approved the required SIP elements:

For each of the 3 States, EPA has fully approved a SIP revision to require emission 

statements as was required for implementation of the 1-hour ozone NAAQS in the Washington 

Area:

With respect to Maryland, see 59 FR 51517, October 12, 1994.

With respect to Virginia, see 60 FR 21451, May 2, 1995.

With respect to the District, see 60 FR 27889, May 26, 1995.

For each of the 3 States, EPA has fully approved a SIP revision to fully implement Stage 

II vapor recovery as was required for implementation of the 1-hour ozone NAAQS in the 

Washington Area:

With respect to Maryland, see 59 FR 29730, June 9, 1994.

 

5 CAA section 171 defines “reasonable further progress” as “incremental reductions in emissions of the relevant air 

pollutant as are required” ... “for ensuring attainment of the applicable NAAQS by the applicable date.” 

6

 See, 64 FR 70460 at 70465, December 16, 1999 and 70 FR 6796 at 6799, February 9, 2005, citing CAA section 

176(c)(2)(A).

7 As part of a an area classified as severe nonattainment under the 1-hour ozone NAAQS, the provisions of CAA 

section 202(a)(4)(D) (rescinding the Stage II mandate of section 182(b)(3)) for areas classified as moderate) did not 

remove the Stage II mandate , and therefore the Stage II requirement was required for the Washington Area when 

part of a severe nonattainment area; sections 51.900(f) and 51.905(a) of the implementation rule for the 1997 ozone 

NAAQS required that Stage II remain in place in the Washington Area until the area can amend its SIP as allowed 

after EPA issues a “widespread use” determination under section 202(a)(4)(D).
With respect to Virginia, see 59 FR 32353, June 23, 1994.

With respect to the District, see 64 FR 57777, October 27, 1999.

For each of the 3 States, EPA has fully approved a SIP revision to implement an 

Enhanced Inspection and Maintenance (E I/M) program in the Washington Area that was 

required for implementation of the 1-hour ozone NAAQS under CAA section 182(c)(3):

With respect to District, see 64 FR 31498, June 11, 1999.

With respect to Maryland, see 64 FR 58340, October 29, 1999.

With respect to Virginia, see 64 FR 47670, September 1, 1999.

 

2. Other Moderate Nonattainment Elements

EPA’s September 20, 2011 final rule approved SIP revisions to fulfill the requirements for RFP, 

RFP contingency measures, RACM generally under CAA section 172(c)(2)(A), and for a base 

year inventory, that is, items (2)(a), (3), (4), (5)(b) and (6) (with respect to the 2008 MVEBs) 

listed in the preceding section III.A. of this TSD. 

As for the RACT requirement (item (2)(b) of the preceding section III.A), the Table 1 provides 

the dates EPA fully approved RACT required under sections 182(b)(2) and 182(f) for the 1997 

Ozone NAAQS, that is, item (2)(b) in section III of this document: 

Table 1. RACT Submittal Dates

State Submittal date(s) Final Approval

District of 

Columbia

September 22, 2008

June 16, 2009 (74 FR 28447)

Maryland

September 12, 2006 & October 11, 

2011 July 13, 2012 (77 FR 41278)

Virginia October 23, 2006 June 16, 2009 (74 FR 28444)

3. Conclusion 

EPA concludes that the 3 States have fulfilled the moderate nonattainment area requirements 

except items (1), and (5)(a) listed in the preceding section III.A of this document. Although EPA 

has determined that the 2009 and 2010 MVEBs are adequate (as discussed in a following section 

of this document) but EPA must approve the attainment demonstration and contingency 

measures in the event the area fails to attain by the attain by the applicable attainment date along 

with the associated 2009 and 2010 MVEBs.

C. Other Determinations Regarding the Washington Area and the June 2007 SIP 

Revisions 

1. Determination of Attainment of the 1997 Ozone NAAQS by the Washington Area

On February 28, 2012 (77 FR 11739), EPA published two determinations regarding the 1997 

ozone NAAQS for the Washington Area. First, EPA made a clean data determination that the 

Washington Area had attained the 1997 ozone NAAQS. 

This determination was based upon complete, quality assured, and certified ambient air 

monitoring data that showed the Washington Area had monitored attainment of the 1997 ozone 
NAAQS for the 2008 – 2010 monitoring period. Ambient air monitoring data for the 2009 –

2011 monitoring period is consistent with continued attainment. Second, pursuant to section 

181(b)(2)(A) of the CAA, EPA made a determination of attainment that the Washington Area 

had attained the 1997 ozone NAAQS by its attainment date of June 15, 2011 as required by 

section 181 of the CAA as interpreted by the implementation rule (40 CFR 51.903) for the 1997 

ozone NAAQS. 

Even though the attainment date for the Washington Area has passed and the area has in fact 

attained the 1997 Ozone NAAQS by that date, EPA believes that approval of the attainment 

demonstration and contingency measures plan in the June 2007 SIP revisions is important 

because such approval strengthens the ozone SIP of each of the 3 States by reserving reductions 

from various measures for the purposes of air quality purposes and by placing lower MVEBs 

into the SIP than those associated with the 2008 RFP plan.

2. Adequacy of the 2009 and 2010 MVEBs

EPA has conducted the process to determine the adequacy of the MVEBs for the entire 

Washington Area which are associated with the attainment demonstration portions of the June 

2007 SIP revisions for the Washington Area. On September 27 , 2012, EPA posted a notice on 

EPA’s website at http://www.epa.gov/otaq/stateresources/transconf/currsips.htm for the purpose 

of opening a 30-day public comment period on the adequacy of the MVEBs for the Washington 

Area in these June 2007 SIP revisions’ attainment demonstration for the entire Washington Area. 

That notice informed the public of the availability of these June 2007 SIP revisions. Following 

EPA’s public comment period that closed on October 29, 2012, before which no comments were 

received, EPA published a notice of adequacy in the Federal Register on February 7, 2013 (76 

FR 9044) which announced EPA had determined that the MVEBs were adequate.8

III. What is EPA’s Review of the 3 States’ Modeled Attainment Demonstration and 

Weight of Evidence Analysis for the Washington Area?

Section 110(a)(2)(K) of the CAA requires states to prepare air quality modeling to show how 

they will meet ambient air quality standards. EPA determined that areas classified as moderate 

or above must use photochemical grid modeling or any other analytical method determined by 

the Administrator to be at least as effective to demonstrate attainment of the ozone health-based 

standard by the required attainment date (November 29, 2005, 70 FR 71612, and 40 CFR 

51.908). On April 30, 2004 (69 FR 23951 and 40 CFR 51.903), EPA specified how areas would 

be classified with regard to the 8-hour ozone standard set by EPA in 1997. On April 30, 2004 

(69 FR 23858), EPA followed these procedures and classified the Washington Area as moderate, 

and the nonattainment area was required to attain the 1997 ozone NAAQS by June 2010. 

Because the attainment date was June 2010 for moderate areas, states had to achieve emission 

reductions by the ozone season of 2009 in order for ozone concentrations to be reduced and show 

attainment during the last complete ozone season before the 2010 deadline. 

A. EPA Guidance for Using Models to Determine Attainment

EPA's photochemical modeling guidance is found at Guidance on the Use of Models and Other 

Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and Regional 

 

8

 EPA’s determination that the 2009 and 2010 MVEBs in the June 2007 SIP revisions has the effect of making the 

2009 VOC and 2010 NOx MVEBs the applicable MVEBs applicable for transportation conformity purposes as of 

February 22, 2013, this proposed action would if issued as a final rule would approve these budgets into the ozone 

SIP of each of the 3 States. 
Haze, EPA-454/B-07-002, April 2007. The photochemical modeling guidance is divided into 

two parts. One part describes how to use a photochemical grid model for ozone to assess 

whether an area will come into attainment of the air quality standard. A second part describes 

how the user should perform supplemental analyses, using various analytical methods, to 

determine if the model over predicts, under predicts, or accurately predicts the air quality 

improvement projected to occur by the attainment date. The guidance indicates that states 

should review these supplemental analyses, in combination with the modeling analysis, in a 

“weight of evidence” assessment to determine whether each area is likely to achieve timely 

attainment.

A description of how the attainment demonstration from these June 2007 SIP revisions 

addresses this EPA modeling guidance for a modeled attainment demonstration can be found in 

“Technical Support Document for the Modeling and Weight of Evidence (WOE) Portions of the 

District of Columbia’s Ozone State Implementation Plan (SIP) Entitled “Plan to Improve Air 

Quality in the Washington, DC-MD-VA Region May 23, 2007” (the “Modeling TSD”) that will 

be available on line at www.regulations.gov, Docket number EPA-R03-OAR-2013-0132 as an 

attachment to this TSD. 

In these June 2007 SIP revisions, the photochemical grid model used projected emissions for 

2009, including emission changes due to regulations the 3 States and neighboring states were 

planning to implement or had already implemented and due to expected growth by the 2009 

ozone season. Meteorological conditions from 2002, the same as the base year modeling, were 

used in the projection modeling for 2009. Using the base case meteorology allows the effect of 

changes in states’ emissions to be determined without being influenced by yearly fluctuations in 

meteorology and is consistent with EPA guidance.

B. Initial Attainment Test Results

The attainment test used in the Washington Area modeling demonstration involved the 

application of model-based relative response factors (RRFs) to base year design values at each 

monitor to produce projected future year design values (2009). The projected 2009 design 

values represent design values that should result from emission controls the 3 States and other 

states planned to have in place in 2009. As discussed in the Modeling TSD, the 2009 design 

values should be less than or equal to 84 parts per billion (ppb) at all monitoring stations to meet 

the attainment test. The SIP modeling predicts that in 2009, the Washington Area will not pass 

the attainment test since the design values at two monitors are projected to be 1 or 2 ppb over the 

84 ppb standard.

In summary, the basic photochemical grid modeling presented in the 3 States’ SIP revisions 

meets EPA’s guidelines and when used with the methods recommended in EPA’s modeling 

guidance, is acceptable to EPA. However, when EPA’s attainment test is applied to the 

modeling results, the only two of seventeen monitors had 2009 ozone design values were 

predicted to exceed the 84 ppb standard in the Washington Area with 2009 projected design 

values of 85 and 86 ppb.9 Thus, based solely upon consideration of EPA’s modeled attainment 

test, the 3 States have not conclusively demonstrated that the Washington Area will reach 

 

9

 The attainment demonstration in the June 2007 SIP revisions considered the monitor network extent in the 

Washington Area as of the time the modeling was done and predicted 2009 design values for only those monitors for 

which sufficient years of complete, quality assured ambient monitoring data was available. The monitoring network 

may have been changed since submission of the June 2007 SIP revisions pursuant to the annual monitoring network 

planning, periodic network assessment and modification procedures of Subpart B to 40 CFR Part 58 “Ambient Air 

Quality Surveillance.”
attainment of the 1997 ozone NAAQS in the attainment year with the modeled emission 

reduction strategies committed to by the 3 States and the neighboring states in the Ozone 

Transport Region (OTR). Therefore, a weight of evidence (WOE) analysis was used by the 3 

States and reviewed by EPA to demonstrate attainment of the 1997 ozone NAAQS in the 

Washington Area. 

C. Weight of Evidence Demonstration

EPA’s modeling guidance describes how to use a photochemical grid model and additional 

analytical methods to complete a WOE analysis to estimate if emissions control strategies will 

lead to attainment of the 1997 ozone NAAQS. This modeling guidance recommends a WOE 

analysis beyond basic supplemental analyses if any future predicted design values fall within the 

range of 82 to 87 ppb (inclusive). The model predicted design values for only four monitors in 

the Washington Area fell within this range, and for the rest of the monitors in the Washington 

area model predicted design values were 81 ppb or less. A WOE analysis is a supporting 

analysis that helps to determine if the results of the photochemical modeling system are correctly 

(or not correctly) predicting future air quality. 

The WOE analysis presented in the 3 States’ SIP revisions describes the analyses performed, 

databases used, key assumptions and outcomes of each analysis, and why the evidence, viewed 

as a whole, supports a conclusion that the Washington Area will attain the 1997 ozone NAAQS 

despite the model prediction that some monitors’ future design values exceed the 1997 ozone 

NAAQS. 

EPA’s review of the 3 States’ WOE analysis in the Modeling TSD and this TSD includes the 

following: (1) a comparison of model-predicted 2009 ozone design values to monitored design 

values for 2003 - 2011; (2) an analysis of recent ozone trends in the Washington Area; and (3) 

alternative methods for calculating the predicted 2009 ozone design value. 

Table 2 of this document compares the model over predicted 2009 ozone design values when 

using the EPA preferred method (Table 2 of the Modeling TSD) to the 2009 – 2011 actual design 

values from Table 3 (below) of this TSD for the four monitors which under the straight 

attainment test had model-predicted 2009 ozone design values in the range of 82 to 87 ppb. 

Table 2. Modeled Predicted 2009 Design Values versus Actual Monitored 

Design Values

Site Information

Design 

Value

Actual Monitored 

Design Values

AIRS ID Site Name Jurisdiction State

Modeled 

2009

2007-

2009

2008-

2010

2009-

2011

51-013-0020 Aurora 

Hills

Arlington 

County

VA 86 79 79 80

51-059-0018 Mount 

Vernon

Fairfax 

County

VA 85 80 I I

51-059-0030 Franconia Fairfax 

County

VA 83 80 81 82

51-059-1005 Annandale Fairfax 

County

VA 82 78 I I

Note: An “I” in a design value column means there was not 3 years of complete data which is 

required to compute a design value according to 40 CFR Part 5010 and Appendix I thereto. 

Some Virginia monitors ceased operation after 2009. All of these monitors were attaining the 

ozone NAAQS at the time operations ceased.
Further, in the Modeling TSD, EPA’s analysis concurs with the 3 States’ analysis of significant 

declining trends for the ozone design values. The Modeling TSD noted that monitored ozone 

design values for each of the Washington Area monitors continued to decline and to show 

attainment in 2010 and 2011. EPA also agrees the 3 States’ analysis of declining trends: (1) in 

number of exceedances, (2) in the ratio of exceedance days to days with a maximum ambient 

temperature over 90 degrees Fahrenheit, (3) in NOx levels as evinced by the declining trend of 

nitrogen dioxide levels, and (4) in spatial extent of exceedances of the 1997 ozone NAAQS in 

the Washington Area. 

The 3 States’ attainment demonstration also asserted that two alternative methods for computing 

an alternative baseline concentration as well as two alternative methods for determining ozone 

response to emissions reductions (the relative response factor (RRF) explained in the Modeling 

TSD) could be used to demonstrate attainment.10 (See, Tables A-1 and A-2 in Appendix A to 

this TSD.) Use of these alternatives would yield a range of baseline design values to which a 

range of RRFs could be applied. The 3 States used these to arrive at up to nine alternative 2009 

predicted design values (each of 3 baseline design values times each of 3 RRFs for a total of up 

to nine 2009 predicted design values for each monitor).

11 The 3 States stated that such a method 

could be used to demonstrate attainment by calculating a minimum and maximum possible 

future design values. 

Using just the alternative baseline design values and the EPA method RRF still yields three 

instances of a 2009 predicted design value over 84 ppb. These are for the monitors at Aurora 

Hills, Mount Vernon and Franconia monitors in Virginia with predicted 2009 design values of 

88, 86 and 85 ppb. (See the columns with plain text and with dashed vertical borders in Table A3 of Appendix A to this TSD) Using the EPA method baseline design values and the two 

alternative RRFs yields just one 2009 predicted design value over 84 ppb of 86 ppb at the Aurora 

Hills site in Virginia. (See the columns with both italic text and dashed vertical borders in Table 

A-3 of Appendix A to this TSD). However, while all the minimum possible future design values 

were 82 ppb or less, EPA notes that three maximum values exceed 84 ppb at the three monitors 

noted in a prior sentence of this paragraph. However EPA notes that if one examines the average 

of all the possible (up to nine) 2009 predicted design values only the Aurora Hills monitor has a 

2009 predicted design value over 84 ppb of 85 ppb. (See, Table A-3 in Appendix A to this 

TSD.) 

C. Actual Ozone Design Values

The recent actual design values for the Washington Area have been below the 84 ppb (0.08 ppm) 

1997 ozone NAAQS. These values are shown in Table 3:

Table 3. Actual Monitored Design Values 2009 to 2011.

Site Data

Actual Monitored Design 

Values (ppb)

AIRS ID Site Name Jurisdiction

Stat

e 

2007-

2009

2008-

2010

2009-

2011

11-001-0025 Takoma District of Columbia --- 77 75 I

11-001-0041 River Terrace District of Columbia --- 78 77 76

11-001-0043 McMillan District of Columbia --- 80 79 79

 

10

 The alternatives are methods related to but differing from those methods EPA provided in the applicable 

guidance.

11 In some cases a monitor may have lacked all the years air quality monitoring data needed to compute an alternate 

design value.
24-009-0010 Calvert Calvert MD 74 77 79

24-017-0010 Southern MD Charles MD 75 75 77

24-021-0037 Frederick Municipal 

Airport

Frederick MD 76 76 76

24-031-3001 Rockville Montgomery MD 78 74 76

24-033-0002 Greenbelt Prince George's MD 78 79 79

24-033-8003 PG Equestrian Center Prince George's MD 78 77 79

51-013-0020 Aurora Hills Arlington County VA 79 79 80

51-059-0005 Chantilly Fairfax County VA 73 I I

51-059-0018 Mount Vernon Fairfax County VA 80 I I

51-059-0030 Franconia Fairfax County VA 80 81 82

51-059-1005 Annandale Fairfax County VA 78 I I

51-059-5001 McLean Fairfax County VA 77 I I

51-107-1005 Ashburn Loudoun County VA 77 75 73

51-153-0009 Long Park Prince William County VA 71 70 69

51-510-0009 Alexandria Alexandria City VA 75 74 77

Notes:

An “I” in a design value column means there was not 3 years of complete data which is required to compute a 

design value according to 40 CFR Part 5010 and Appendix I thereto. Some Virginia monitors ceased operation after 

2009. All of these monitors were attaining the ozone NAAQS at the time operations ceased.

Sources:

The 2007 to 2009 and the 2008 to 2010 design values are from Tables 1 and 2, respectively, from the notice of 

proposed rulemaking (76 FR 58206 at 58208-58209, September 20, 2011) for the February 28, 2012 (77 FR 11739) 

final rule regarding two determinations about the status of the Washington Area under 1997 ozone NAAQS.

The 2009-2011 design values are from “Ozone Detailed Information (excel file 

Ozone_DesignValues_20092011_FINAL_08_06_12 .XLSX, 558k) - Updated on August 7, 2012 downloaded from 

http://www.epa.gov/airtrends/values.html on February 22, 2013. 

All design values in the original sources have been converted from ppm to ppb by multiplying the design value in 

ppm by the conversion factor 1000 ppb/ppm..

D. Conclusions:

EPA has determined with the benefit of 2009 monitored design values that the model in the 3 

States’ June 2007 SIP revisions over predicted the actual concentrations.

EPA believes that the 3 States’ photochemical grid modeling results predict a 2009 projected 

design value at most 2 ppb well above the 1997 ozone NAAQS for the Washington Area. 

However, after taking into account WOE considerations regarding model over prediction of the 

actual 2009 monitored design values and recent ozone design value trends and other trends 

related to the extent and severity of the ozone problem, which show attainment of the standard 

by 2010, EPA believes that the 3 States’ June 2007 SIP revisions has demonstrated attainment of 

the ozone standard by the attainment date of June 15, 2010.

IV. What Control Measures and Emission Reductions are included in the plan for 

Attainment and Contingency Measures?

A. RFP Measures:
All of the measures which were used to demonstrate RFP are part of the measures for obtaining 

the reductions needed for attainment. These are described in the TSD prepared for the approval 

of the RFP plan (hereafter the RFP TSD).

12

The RFP plan relied solely upon VOC reductions from these measures. See Table 6 in the June 

30, 2011 notice of proposed rulemaking (NPR) (73 FR 38334 at 38337) for the September 20, 

2011 final rule approving the RFP plan. Some of these measures also provide reductions in NOx 

emissions as well. These include most of the federal nonroad and on-road mobile sources 

emissions standards and other on-road mobile sources controls such as enhanced I/M or the 

transportation control measures.

Most of the contingency measure reductions to address any failure to achieve RFP were NOx 

reductions. See Section II.E of the June 30, 2011 NPR (73 FR 38334 at 38337-38338) for the 

September 20, 2011 final rule approving the RFP plan. 

Likewise, most of the RFP plan measures provide additional VOC reductions in the 2009 

attainment year over and above those projected for the RFP year of 2008. These include federal

nonroad and on-road mobile sources emissions standards, and some area source rules such as 

those covering portable fuel containers where older vehicles, engines or containers that were 

required to meet less stringent emissions standards (or in some cases no standards) are replaced 

by newer vehicles, engines or containers required to meet the more stringent standards of later 

federal and state rules. Because the attainment plan must provide for reductions in 2009 to 

offset growth in emissions between 2008 and 2009, the expected emission reductions for most 

measures are calculated relative to the projected 2009 activity levels (which in most cases is 

greater than that in 2008) and uncontrolled emissions. As an example of how this occurs, 

consider the following hypothetical case: suppose a measure requires a 30 percent reduction in 

VOC emission rates before January 1, 2008; further suppose the source category emits 1 ton of 

VOC or NOx per 100 units of activity (gallons of fuel or product used/produced per year) and 

the 1998 projected activity level is 1,000 units and the projected activity level for 2009 is 1,100 

units per year. The 2008 uncontrolled emissions would be 10 tons (1 ton/100 units of activity 

times 1,000 units) and the reductions projected for 2008 would be 3 tons. The 2009 uncontrolled 

emissions would be 11 tons (1 ton/100 units times 1,100 units) and the reductions projected for 

2008 would be 3.3 tons a gain of 0.3 tons due solely to the higher projected activity level for 

2009. In addition, the plan relied upon some additional measures beyond those used to 

demonstrate RFP for which the following section of this document provides a summary. 

B. Additional Measures beyond the RFP Plan

The plan relied upon additional measures and reductions beyond those used to demonstrate RFP. 

1. RFP Plan Measures – Additional reductions after 2008

First of some of the RFP measures also provide reductions in NOx emissions in addition to the 

VOC reductions credited towards the RFP requirement. These include the various on-road motor 

vehicle and nonroad engine emission standards regulations.

 

12 Refer to the “RFP TSD” – “Technical Support Document — District of Columbia, Maryland, and Virginia; 2002 

Base Year Emissions Inventory, Reasonable Further Progress Plan, Contingency Measures, Reasonably Available 

Control Measures, and Transportation Conformity Budgets for the Metropolitan Washington, DC 1997 8-Hour 

Ozone Moderate Nonattainment Area,” dated May 26, 2011, (originally docketed as item EPA-R03-OAR-2010-

0475-0006 in Docket Number EPA-R03-OAR-2010-0475) a copy of which has been included in the docket for this 

proposed rule.
2. New measures

Additionally, the plan relies upon new SIP requirements including those amending existing state

regulations for area source categories to add emission standards for additional categories of 

consumer products or to lower standards for previously regulated products such as portable fuel 

containers. Also the 3 States agreed to adopt regulations for industrial adhesives and sealants. 

Specifically, the attainment plan relied upon the following new measures: 

(1) Regulations controlling VOC emissions from industrial adhesives and sealants in Maryland 

and Virginia with such regulations conforming to the emission standards of a “model rule” 

prepared by the Ozone Transport Commissions (OTC);

(2) A second “phase” of control by Virginia on VOC emissions from portable fuel containers by 

imposing more stringent standards than the initial regulations with such standards conforming to 

those of a “model rule” prepared by the OTC. 

(3) A second “phase” of control by Virginia on VOC emissions from consumer products by 

imposing emission standards for additional classes of consumer products with such standards 

conforming to those of a “model rule” prepared by the OTC. 

All of these rules have been fully approved by EPA into the applicable state SIP. See, 76 FR 

64237, October 18, 2011and 76 FR 51925, August 19, 2011 (regarding Maryland adhesives and 

sealants rule); and 77 FR 3928, January 26, 2012 and 76 FR 69214, November 8, 2011 

(regarding Virginia’s adhesives and sealants rule, phase 2 portable fuel containers rule and phase 

2 consumer products rule) for further details on these approvals and further description of these 

rules. 

Maryland also instituted a second phase of control on consumer products and portable fuel 

containers with such standards conforming to those of a “model rule” prepared by the OTC, but 

Maryland’s rules required compliance before the end of calendar year 2008 and so are not rules 

beyond those for the RFP plan. (The District of Columbia committed to adopting and submitting 

as a SIP revision regulations conforming to those of the “model rules” prepared by the OTC for 

these categories, but any emission reductions arising from these measures in the District are not 

applied to the emissions reductions upon which the attainment modeling and contingency 

measure demonstration relied.)

3. RFP Contingency Plan Measures

In addition, some of the reductions scheduled to occur by the end of 2009 upon which the 

contingency plan for a failure to achieve adequate RFP by the end of calendar year 2008 relied, 

are part of the reductions upon which the attainment demonstration relies. The specifically 

identified measures supplying these reductions are the portable fuel containers rules (reductions 

occurring as a result of rule phases 1 and 2) and reductions from beyond RACT-level control of 

NOx sources attributable to federal regulations and state/regional initiatives. These include: (1) 

“NOx Budget” rules that required a second phase of stationary source NOx reductions as part of 

a coordinated regulatory initiative by the Ozone Transport Region (OTR) states to further reduce 

NOx emissions in the Northeast; and EPA’s “NOx SIP Call” to reduce ozone transport in the 

Eastern United States (refer to 40 CFR 51.121).13 These also include: (3) EPA's Clean Air 

 

13 See, 63 FR 57491, Oct. 27, 1998, as amended at 63 FR 71225, Dec. 24, 1998; 64 FR 26305, May 14, 1999; 65 FR 

11230, Mar. 2, 2000; 65 FR 56251, Sept. 18, 2000; 69 FR 21642, Apr. 21, 2004; 70 FR 25317, May 12, 2005; 70 
Interstate Rule (CAIR) codified at 40 CFR 51.123 & 51.124; and (4) Maryland's Healthy Air Act 

(MD HHA). Of these, the MD HAA and the CAIR rule are applicable as these two are the main 

operative rules setting allocations for large sources of NOx for the years 2009 and later although 

some sources covered by earlier rules but not affected by CAIR may remain subject to those 

earlier rules. 

The CAIR requires NOx and sulfur oxides emission reductions from large fossil fuel-fired 

electric generating units. The rule is set up in several phases with the first phase of NOx 

reductions to come by 2009. On July 11, 2008, the U. S. Court of Appeals for the DC Circuit 

issued its decision to vacate and remand both CAIR and the associated CAIR FIPs (North 

Carolina v. EPA, 531 F.3d 836 (DC Cir., 2008). However, in response to EPA’s petition for 

rehearing, the court issued an order remanding CAIR to EPA without vacating either CAIR or 

the CAIR FIPs (North Carolina v. EPA, 550 F.3d 1176 (DC Cir., 2008)). The court, thereby, left 

CAIR in place in order to “temporarily preserve the environmental values covered by CAIR” 

until EPA replaces it with a rule consistent with the court’s opinion (id. at 1178). Because CAIR 

has been remanded to EPA without vacatur, CAIR and CAIR FIPs are currently in effect in 

Maryland, Virginia and the District.

Virginia’s NOx budget and ozone season trading regulations adopted in response to CAIR are 

found in Title 9 of the Virginia Administrative Code, Agency 5, Chapter 140 (9 VAC 5 Chapter 

140). EPA approved Virginia CAIR program into the Virginia SIP in 2007 (72 FR 73602

On November 1, 2001 (66 FR 55099), EPA approved the District’s Nitrogen Oxides Emissions 

Budget Program (20 DCMR, Chapter 10) which addressed the NOx SIP call and regional 

initiatives. ). EPA put a Federal Implementation Plan (FIP) in place for the District in 2006 (71 

FR 25328, April 26, 2006, 72 FR 62345, November 2, 2007, as amended at 76 FR 48362, 

August 8, 2011) which is codified at 40 CFR 52.484 with respect to NOx reductions.

EPA has approved Maryland’s rules addressing the NOx SIP call, regional initiatives, CAIR and 

the MD HAA. These are found in Code of Maryland Regulations (COMAR) Title 26, Subtitle 

11, Chapter 27 (COMAR 26.11.27) (Regulations .01 through .04 and .05 through .06), COMAR 

26.11.28 (Regulations .01 through .08) regarding CAIR, COMAR 26.11.29 (Regulations .01 

through .15), and COMAR 26.1130 (Regulations .01 through .09).

Table 4 provides the dates of EPA’s approval final actions:

Table 4. EPA’s Approvals of Maryland NOx Rules

COMAR Rule Cite Publication Date Federal Register Citation

26.11.27 September 4, 2008 73 FR 51599

26.11.28 October 30, 2009 74 FR 56117

26.11.29 March 22, 2004 69 FR 13236

26.11.30 November 3, 2006 71 FR 64647

C. Summary of Emissions Reductions

The following Table 5 provides a summary of the attainment plan’s measures and the projected 

2009 emission reductions. 

 

FR 51597, Aug. 31, 2005; 73 FR 21538, Apr. 22, 2008; 76 FR 48353, Aug. 8, 2011.
 Table 5. Control Measures and 2009 Emission Reductions in the Washington Area

Source Sector

Reductions (tons per day)

Plan Ref. 

No. Note 1 VOC NOx

Point Source Measures – RFP Plan Contingency Measures

6.1.2 State NOx RACT and Regional NOx Transport 

Requirement (RACT, NOx SIP Call, CAIR, HAA) 0.00 128.76

Subtotal ...Point Source Measures ... 0.00 128.76

Area Sources Measures

RFP Plan Area Source Measures – 2009 reductions

6.2.11 Mobile Equipment Repair and Refinishing Rule 3.59 0.0

6.2.12 Portable Fuel Containers Rule: Phase I 9.3 0.0

6.2.13 Architectural and Industrial Maintenance Coatings 

Rule 10.82 0.0

6.2.14 Reformulated Consumer Products Rule: Phase I 6.34 0.0

6.2.15 Solvent Cleaning Operations Rule 2.99 0.0

6.2.16 Industrial Adhesives and Sealants Rule 2.42 0.0

Additional Area Source Measures Beyond the RFP Plan – 2009 Reductions

6.2.18 Reformulated Consumer Products Rule: Phase II 0.76 0.0

6.2.17 Portable Fuel Containers Rule: Phase II 0.75 0.0

Subtotal ... Area Sources Measures ... 36.97 0.00

Nonroad Measures (NONROAD Model) Note 2

6.3.1 EPA Non-Road Gasoline Engines Rule 

42.44 14.76

6.3.2 EPA Non-Road Diesel Engines Rule

6.3.3 Emissions standards for spark ignition marine 

engines

6.3.4 Emissions standards for large spark ignition 

engines

Other Nonroad Measures (not covered by the NONROAD Model)

6.3.6 Standards for Locomotive 0.06 2.74

Subtotal ...Nonroad Source Measures ... 42.50 17.50

Onroad Measures (MOBILE and TDM Model) Note 3

6.4.2 Enhanced Vehicle Inspection/Maintenance (I/M)

7.17 37.63

6.4.4 National Low Emission Vehicle Program

6.4.5 Tier 2 Motor Vehicle Emission Standards

6.4.6 Heavy-Duty Diesel Engine Rule

Other Onroad Measures Note 4

6.4.7 Transportation Control Measures, Vehicle

Technology, Fuel, or Maintenance Measures 0.18 0.45

Subtotal On-road Mobile Source Measures 7.35 38.08

Other Measures

6.5 Voluntary Bundle 0.19 0.30

Subtotal Other Measures 0.19 0.30
Totals ...... 87.01 184.64

Notes:

1. The measure number assigned in Chapter 6 of the plan document of the June 2007 SIP Revisions.

2. The NONRPOAD model can be run to project emissions from all classes of nonroad engines covered by this 

model for an entire geographic area. This model will apply all applicable emission standards to all classes of 

nonroad engines covered by this model for an entire geographic area... Therefore, the total emissions reductions 

from all applicable EPA nonroad engine rules are presented in aggregate. Locomotive engines are not included 

within the scope of the NONROAD Model.

2. On-road mobile source emissions require the use of two models. The first is EPA’s MOBILE6 model which 

generates emissions factors. The model can be configured to generate emissions factors that account for all EPA 

emissions standards, fuel standards and state implemented measures (such as I/M)) applicable in the area for the 

year being modeled. The 3 States have elected to run the MOBILE6 model in this manner. The 3 States thus 

generated emissions factors that account for all the control programs simultaneously; therefore, the reductions from 

each individual program are not computed, only the aggregate reductions. The second model is the transportation 

demand model (TDM) which predicts future year activity levels for on-road mobile sources – vehicle miles 

travelled and vehicle starts – for the Washington Area which accounts for the planned changes in the highway 

network. The future year emissions factors are applied to the activity levels to generate predicted emissions level. 

3. Certain measures are not easy to quantify using MOBLE6 and the TDM because their impact is below the 

resolution of the TDM model. Some are transportation control measures designed to reduce vehicle miles traveled 

or vehicle trips. Other of these measures represents retrofit of transit vehicles or purchase of cleaner fueled transit 

buses.

D. Contingency Plan Reductions

Section 172(c)(9) of the CAA requires that SIPs contain additional contingency measures that 

will take effect without further action by the state or EPA if an area fails to attain an ambient air 

quality standard in this case the 1997 ozone NAAQS by the applicable date, or fails to achieve 

sufficient RFP.

14

 The CAA does not specify how many contingency measures are needed or the 

magnitude of emissions reductions that must be provided by these measures. However, EPA 

provided initial guidance interpreting the contingency measure requirements of section 172(c)(9) 

in the April 16, 1992, General Preamble for Implementation of the Act (See 57 FR 13498 at 

13510, April 16, 1992). EPA’s interpretation is based upon the language in section 1872(c)(9) 

and in conjunction with the control measures requirements of sections 172(c), 182(b) and 

182(c)(2)(B), the reclassification and failure to attain provisions of section 181(b) and other 

provisions. In the April 16, 1992 initial guidance EPA indicated that states with ozone 

nonattainment areas classified as moderate and above should include sufficient contingency 

measures so that, upon implementation of such measures, additional emission reductions of up to

3 percent of the emissions in the adjusted base year inventory (or such lesser percentage that will 

cure the identified failure) would be achieved in the year following the year in which the failure 

has been identified.15 The state must show that the contingency measures can be implemented 

with minimal further action on their part and with no additional rulemaking actions. 

EPA allows areas to use as contingency measures one or more federal or local measures that are 

in place and provide reductions that are in excess to the attainment demonstration (or RFP plan) 

and has approved numerous SIPs under this interpretation. Refer to the discussion and citations 

 

14 EPA has already approved contingency measures related to for any failure to make RFP as discussed in section 

IV.B elsewhere in this document. This proposed rule therefore only applies to approval of contingency measures 

needed to address the failure to attain by the applicable attainment date “prong” in section 179(c)(9). 

15

 The requirement for and the method for the computation of an “adjusted base year inventory” is explained in the 

NPR for the September 20, 2011 final rule under the heading B. Adjusted Base Year Inventory, 2008 RFP Target 

Levels. See 76 FR 38334 at 38336, June 30, 2011.
under “3. Comments and Responses” at 70 FR 71612 at 71651, November 29, 2005. EPA 

believes that any additional reductions from measures in the attainment strategy occurring after 

the applicable attainment date are clearly in excess to those needed for attainment. The modeling 

demonstration was based upon projected emissions levels for the year 2009 and therefore 

reductions occurring after the end of calendar year 2009 would be excess to attainment needs. 

The applicable attainment date was June 15, 2010 based upon an effective date of designation 

under the 1997 ozone NAAQS of June 15, 2004. See, 69 FR 28858, April 30, 2004 and Table 1 

in 40 CFR 51.903. The earliest EPA make a determination of attainment or failure to achieve 

attainment for the Washington Area would be sometime in 2010; therefore, under the April 16, 

1992 initial guidance discussed in the previous paragraph, the earliest the “year following the 

year the failure was identified ” would be in 2011. Therefore, EPA believes that reductions 

occurring after 2009 and as early as 2010 and as late as 2011 would qualify for contingency 

measures to address the failure to attain prong in section 179(c)(9) insofar as being both excess 

to attainment and satisfying the timing of reductions requirements. Excess reductions from 

measures already in place, that is, being implemented, clearly meet a requirement that 

contingency measures be implemented with minimal further action by the state and with no 

additional rulemaking actions. For more information on contingency measures, see the April 16, 

1992 General Preamble (57 FR 13512) and the November 29, 2005 Phase 2 8-hour ozone 

implementation rule (70 FR 71612 at 71650). 

Because the Washington area’s attainment demonstration relies upon both VOC and NOx 

reductions, acceptable contingency measures can include NOx and VOC reductions.

16

 For the 

failure to attain contingency requirement, the 3 States identified specific measures yielding 8.46 

tons per day of VOC emissions reductions and 6.05 tons per day of NOx emissions reductions. 

These are identified in Chapter 11 of the June 2007 SIP revision document which is reproduced 

below in Table 6:

Table 6. Contingency Measure Reductions for the Attainment Demonstration

Plan 

Ref. No. Contingency Measure

Reductions (tons per 

ozone season day)

VOC NOx

6.4.5 Tier 2 Motor Vehicle Emission Standards 0.0 1.77

6.3.1 Phase I and Phase II Emissions Standards for GasolinePowered Non-Road Utility Engines 1.49 0.04

6.3.2 Emissions Standards for Diesel-Powered Non-Road 

Utility Engines of 50 or More Horsepower 

0.39 3.28

6.3.3 Emissions Standards for Spark Ignition Marine Engine 1.42 0.0

6.3.4 Emissions Standards for Large Spark Ignition Engines 0.54 0.96

6.2.12 & 

6.2.17

Ozone Transport Commission Portable Fuel Containers 

Rule 

4.62 0.0

TOTAL REDUCTIONS 8.46 6.05

Reductions for the Tier 2 motor vehicle emission standards occur between 2009 and 2010. 

(There may be reductions in VOC emissions resulting from the Tier 2 motor vehicle standards 

but the 3 States have elected not to apply any of these towards the contingency requirement.) 

Reductions for the other identified measures occur between 2009 and 2011. The 3 States have 

 

16

 Such a result comports well with section 182(b)(1)(A) which requires a moderate area plan to provide for

“reductions in volatile organic compounds and oxides of nitrogen as necessary to attain” the 1997 ozone NAAQS by 

the applicable attainment date for moderate areas.
implemented the contingency reductions from the on-road mobile sources via establishment of a 

2010 MVEBs. Even though additional reductions in VOC emissions from on-road mobile 

sources may occur between 2009 and 2010 the states have elected not to count these towards the 

contingency requirement. Thus the 2010 MVEBs reflect only a reduction in NOx emissions.

EPA believes that all of these measures achieve additional reductions beyond those needed to 

offset growth in activity levels as new motor vehicles, nonroad vehicle and locomotive engines, 

or portable fuel containers replace older items which either were subject to less stringent 

emissions standards or no emission standards regulations. These reduction amounts represent a 

1.941 percent reduction in VOC emissions and a 1.069 percent reduction in NOx emissions as 

shown in Table 7 of this document. 

Table 7. Calculation of VOC and NOx Reductions for Attainment Contingency

(Ozone Season tons per day)

Item Description VOC NOx

(a) 2002 Base-Year Inventory 448.28 597.22

(b) Non-creditable Emissions Reduction 12.45 31.61

(c) Adjusted Base-Year Inventory = Item (a) minus 

Item (b)

435.83 565.61

(d) 1.941% VOC Reduction Required for Attainment

Contingency = (1.941 /100) times Item (c)

8.459

(e) 1.069% NOx Reduction Required for Attainment

Contingency = (1.069/100) times Item (c)

6.046

The June 2007 SIP revision plan document (in Table 11-3) shows a calculation for the attainment 

contingency as being 0.3 percent VOC and 2.7 percent NOx. But the remainder of the 

discussion is for the measures listed in Table 6 of this TSD and the emissions reductions shown 

in Table 6. EPA concludes that Table 11-3 is in error. In any event, EPA believes that the states 

have identified enough reductions from specific measures to fulfill the contingency requirement. 

VII. What are the Transportation Conformity Budgets?

Transportation conformity is required by CAA section 176(c). EPA’s conformity rule requires 

that transportation plans, programs and projects conform to state air quality implementation 

plans and establishes the criteria and procedure for determining whether or not they do. 

Conformity to a SIP means that transportation activities will not produce new air quality 

violations, worsen existing violations, or delay timely attainment of a national ambient air 

quality standard such as the 1997 ozone NAAQS. The criteria by which EPA determines whether 

a SIP’s MVEBs are adequate for conformity purposes are outlined in 40 CFR 93.118(e)(4). The 

process for determining the adequacy of submitted SIP budgets is described in 40 CFR 93.118(f). 

States must establish VOC and NOx MVEBs for the attainment year and submit these MVEBs to 

EPA for approval. Upon adequacy determination or approval by EPA, states must conduct 

transportation conformity analysis for their Transportation Improvement Programs (TIPs) and 

long range transportation plans to ensure highway vehicle emissions will not exceed relevant 

MVEBs. Failure to demonstrate such transportation conformity results in freezing of federal

highway funds and all federal highway projects in the lapsed area. The 3 States discuss 

transportation conformity in Section 8.0 of the Washington Area 8-hour ozone plan. The 3 

States describe their methods and provide detailed input parameters used in modeling the 

inventories in Appendices E1 and E2 of the Washington Area 8-hour ozone plan. In the 
Washington Area, the Metropolitan Washington Air Quality Committee (MWAQC) consults 

with the Transportation Planning Board (TPB) to establish mobile source emissions budgets. 

In addition to the 2009 MVEBs required for the attainment year, the 3 States have implemented 

the NOx contingency reductions from the on-road mobile sources via establishment of a 2010 

MVEB for NOx. 

The Washington Area MVEBs for the attainment demonstration and contingency measures are 

based on the projected 2009 and 2010, respectively, mobile source emissions, accounting for all 

mobile control measures. The budgets are equal to the projected 2009 and 2010, respectively, 

on-road mobile source emission inventories minus reductions from transportation control 

measures. 

The MVEBs for the 2009 attainment year and the 2010 contingency plan NOx MVEBs are 

shown in Table 8. These are the budgets EPA determined were adequate in the February 7, 2013 

(76 FR 9044) notice of adequacy.

Table 8. The Washington Area MVEBS for the 2009 Attainment Plan 

and 2010 Contingency Plan

Budget Type 

Budget 

Year

MVEBs

VOC (tons per day) NOx (tons per day)

Attainment 

Year 2009 66.5 146.1

Contingency 

Plan 2010 N/A 144.3

That the plan document of the June 2007 SIP revisions shows a budget of 66.5 tons per day of 

VOC for 2010 (which is numerically the same as that for 2009) is now of no real import. Under 

the transportation conformity rules conformity must be determined against the budgets in the 

SIP. Because all future conformity determinations will evaluated for years after 2010, the budget 

of 66.5 tons of VOC per day for 2009 remains the applicable VOC budget if there were no 

budget for 2010. If there was a 66.5 tons per day budget for 2010 it would place the same 

constraint on future motor vehicle emissions as the 2009 budget. 

VII. Summary and Recommendations: 

The EPA Region III Air Protection Division (APD) has reviewed the 3 States’ attainment 

demonstration plan, contingency measures for failure to attain for the Washington Area and 

found them to be approvable. In addition, in the September 20, 2011 (76 FR 58116) final rule 

EPA has determined that the 3 States used acceptable techniques and methodologies to develop 

the Washington Area 2002 base year emission and milestone year projected inventories . 

Furthermore, EPA has determined that the 2009 and 2010 attainment year and contingency year, 

respectively, MVEBs in the June 2007 SIP revisions for the Washington Area adequate for 

transportation conformity purposes in the February 7, 2013 (76 FR 9044) notice of adequacy.

Therefore, APD recommends approval of the following SIP elements in the June 2007 SIP 

revisions for the Washington, DC-MD-VA moderate nonattainment area: the attainment 
demonstration and associated 2009 MVEBs and the contingency measures for failure to attain 

and the associated 2010 MVEB.

Attachments:

“Technical Support Document for the Modeling and Weight of Evidence (WOE) Portions of the 

District of Columbia’s Ozone State Implementation Plan (SIP) Entitled “Plan to Improve Air 

Quality in the Washington, DC-MD-VA Region

May 23, 2007”

“Technical Support Document — District of Columbia, Maryland, and Virginia; 2002 Base Year 

Emissions Inventory, Reasonable Further Progress Plan, Contingency Measures, Reasonably 

Available Control Measures, and Transportation Conformity Budgets for the Metropolitan 

Washington, DC 1997 8-Hour Ozone Moderate Nonattainment Area,” dated May 26, 2011, 

(originally docketed as item EPA-R03-OAR-2010-0475-0006 in the docket for the September 

20, 2011 final rule – Docket Number EPA-R03-OAR-2010-0475) a copy of which has been 

included in this docket as an attachment to this TSD.
Appendix A to Technical Support Document for Approval and Promulgation of Air Quality Implementation Plans; 

District of Columbia, Maryland and Virginia; Attainment Demonstration for the 1997 8-Hour Ozone National 

Ambient Air Quality Standard for the Washington, DC-MD-VA Moderate Nonattainment Area (Docket ID#: EPAR03-OAR-2013-0132)

Table A-1 Alternative baseline design values A B C

State Jurisdiction AIRS ID Site Name 

EPA 

Method 

DVB

2001-

2003 

DVB

2000-

2004 

Straight 

Average 

DVB

D 

Minimum 

value in 

Cols A-C

E 

Maximum 

value in 

Cols A-C

--- District of Columbia 11-001-0025 Takoma 88.7 88 87.6 87.6 88.7

--- District of Columbia 11-001-0041 River Terrace 89.0 92 85.2 85.2 92.0

--- District of Columbia 11-001-0043 McMillan 92.7 94 89.6 89.6 94.0

MD Calvert 24-009-0010 Calvert NA NA NA NA NA 

MD Charles 24-017-0010 Southern MD 93.0 94 91.6 91.6 94.0

MD Frederick 24-021-0037 

Frederick Municipal 

Airport 87.3 88 85.8 85.8 88.0

MD Montgomery 24-031-3001 Rockville 86.7 88 85.2 85.2 88.0

MD Prince George's 24-033-0002 Greenbelt 94.0 93 92.5 92.5 94.0

MD Prince George's 24-033-8003 PG Equestrian Center 94.0 NA 94.7 94.0 94.7

VA Arlington County 51-013-0020 Aurora Hills 96.7 99 92.8 92.8 99.0

VA Fairfax County 51-059-0005 Chantilly 87.0 89 85.2 85.2 89.0

VA Fairfax County 51-059-0018 Mount Vernon 96.7 97 95.4 95.4 97.0

VA Fairfax County 51-059-0030 Franconia 95.0 97 91.8 91.8 97.0

VA Fairfax County 51-059-1005 Annandale 94.0 NA 94.0 94.0 94.0

VA Fairfax County 51-059-5001 McLean 88.0 88 86.0 86.0 88.0

VA Loudoun County 51-107-1005 Ashburn 90.0 92 87.0 87.0 92.0

VA Prince William County 51-153-0009 Long Park 85.0 87.0 83.6 83.6 87.0

VA Alexandria City 51-510-0009 Alexandria 90.0 92.0 86.8 86.8 92.0

Note: DVB means baseline design value

From Table 10-7. Methodologies for Calculating Baseline Design Values in the June 007 SIP 

Revisions
Appendix A to Technical Support Document for Approval and Promulgation of Air Quality 

Implementation Plans; District of Columbia, Maryland and Virginia; Attainment Demonstration for the 

1997 8-Hour Ozone National Ambient Air Quality Standard for the Washington, DC-MD-VA Moderate 

Nonattainment Area (Docket ID#: EPA-R03-OAR-2013-0132)

Table A-2 Alternative Relative Response Factors (RRFs)

G H J

AIRS ID Site Name

EPA 

Method

9-Cell 

Average 

Method

Grid 

Cell 

Only 

Method

K 

Minimum 

value in 

Cols G-J 

L 

Maximum 

value in 

Cols G-J

EPA 

Methods: 

DVB 

times 

EPA 

RRF

11-001-0025 Takoma 0.892 0.874 0.886 0.874 0.892 79.1

11-001-0041 River 0.883 0.872 0.909 0.872 0.909 78.6

11-001-0043 McMillan 0.883 0.872 0.909 0.872 0.909 81.9

24-009-0010 Calvert 0.836 0.815 0.81 0.81 0.836

24-017-0010 Southern MD 0.808 0.806 0.794 0.794 0.808 75.1

24-021-0037 

Frederick Municipal 

Airport 0.846 0.833 0.844 0.833 0.846 73.9

24-031-3001 Rockville 0.881 0.861 0.86 0.86 0.881 76.4

24-033-0002 Greenbelt 0.869 0.857 0.857 0.857 0.869 81.7

24-033-8003 PG Equestrian Center 0.865 0.838 0.837 0.837 0.865 81.3

51-013-0020 Aurora Hills 0.891 0.875 0.893 0.875 0.893 86.2

51-059-0005 Chantilly 0.867 0.858 0.888 0.858 0.888 75.4

51-059-0018 Mount Vernon 0.883 0.872 0.868 0.868 0.883 85.4

51-059-0030 Franconia 0.88 0.873 0.877 0.873 0.880 83.6

51-059-1005 Annandale 0.88 0.873 0.877 0.873 0.880 82.7

51-059-5001 McLean 0.883 0.869 0.864 0.864 0.883 77.7

51-107-1005 Ashburn 0.869 0.872 0.874 0.869 0.874 78.2

51-153-0009 Long Park 0.871 0.865 0.866 0.865 0.871 74.0

51-510-0009 Alexandria 0.883 0.872 0.868 0.868 0.883 79.5

From Table 10-8. Methodologies for Calculating Relative Response Factors in the June 007 SIP Revisions

Note: There is no Column "I." 
Appendix A to Technical Support Document for Approval and Promulgation of Air Quality Implementation Plans; District of Columbia, Maryland and 

Virginia; Attainment Demonstration for the 1997 8-Hour Ozone National Ambient Air Quality Standard for the Washington, DC-MD-VA Moderate 

Nonattainment Area (Docket ID#: EPA-R03-OAR-2013-0132)

Table A-3 Matrix of alternative baseline design values times alternative RRFs

DVB 

method

2001-

2003 

DVB

2000-

2004 

Straight 

Average 

DVB

EPA 

Method 

DVB

2001-

2003 

DVB

2000-

2004 

Straight 

Average 

DVB

EPA 

Method 

DVB

2001-

2003 

DVB

2000-

2004 

Straight 

Average 

DVB

AIRS ID Site Name

RRF 

Method

EPA 

RRF

EPA 

RRF

9-cell 

RRF

9-cell 

RRF

9-cell 

RRF

Grid cell 

RRF

Grid cell 

RRF

Grid cell 

RRF

Average of 

all 

combinations

11-001-0025 Takoma 78.5 78.1 77.5 76.9 76.6 78.6 78.0 77.6 77.7

11-001-0041 River 81.2 75.2 77.6 80.2 74.3 80.9 83.6 77.4 78.8

11-001-0043 McMillan 83.0 79.1 80.8 82.0 78.1 84.3 85.4 81.4 81.8

24-009-0010 Calvert 

24-017-0010 Southern MD 76.0 74.0 75.0 75.8 73.8 73.8 74.6 72.7 74.5

24-021-0037 Frederick Municipal Airport 74.4 72.6 72.7 73.3 71.5 73.7 74.3 72.4 73.1

24-031-3001 Rockville 77.5 75.1 74.6 75.8 73.4 74.6 75.7 73.3 75.0

24-033-0002 Greenbelt 80.8 80.4 80.6 79.7 79.3 80.6 79.7 79.3 80.0

24-033-8003 

PG Equestrian 

Center 81.9 78.8 79.4 78.7 79.3 79.6

51-013-0020 Aurora Hills 88.2 82.7 84.6 86.6 81.2 86.4 88.4 82.9 85.1

51-059-0005 Chantilly 77.2 73.9 74.6 76.4 73.1 77.3 79.0 75.7 75.9

51-059-0018 Mount Vernon 85.7 84.2 84.3 84.6 83.2 83.9 84.2 82.8 84.1

51-059-0030 Franconia 85.4 80.8 82.9 84.7 80.1 83.3 85.1 80.5 82.8

51-059-1005 Annandale 82.7 82.1 82.1 82.4 82.4 82.3

51-059-5001 McLean 77.7 75.9 76.5 76.5 74.7 76.0 76.0 74.3 76.0

51-107-1005 Ashburn 79.9 75.6 78.5 80.2 75.9 78.7 80.4 76.0 78.2

51-153-0009 Long Park 75.8 72.8 73.5 75.3 72.3 73.6 75.3 72.4 73.9

51-510-0009 Alexandria 81.2 76.6 78.5 80.2 75.7 78.1 79.9 75.3 78.2
Appendix A to Technical Support Document for Approval and Promulgation of Air 

Quality Implementation Plans; District of Columbia, Maryland and Virginia; Attainment 

Demonstration for the 1997 8-Hour Ozone National Ambient Air Quality Standard for 

the Washington, DC-MD-VA Moderate Nonattainment Area (Docket ID#: EPA-R03-

OAR-2013-0132)

Table A-4 Minimum and Maximum predicted 2009 design values from Table A-3

AIRS ID Site Name Jurisdiction State 

M 

Minimum

N 

Maximum

11-001-0025 Takoma 

District of 

Columbia --- 76.6 79.1

11-001-0041 River Terrace 

District of 

Columbia --- 74.3 83.6

11-001-0043 McMillan 

District of 

Columbia --- 78.1 85.4

24-009-0010 Calvert Calvert MD 

24-017-0010 Southern MD Charles MD 72.7 76.0

24-021-0037 

Frederick Municipal 

Airport Frederick MD 71.5 74.4

24-031-3001 Rockville Montgomery MD 73.3 77.5

24-033-0002 Greenbelt Prince George's MD 79.3 81.7

24-033-8003 PG Equestrian Center Prince George's MD 78.7 81.9

51-013-0020 Aurora Hills Arlington County VA 81.2 88.4

51-059-0005 Chantilly Fairfax County VA 73.1 79.0

51-059-0018 Mount Vernon Fairfax County VA 82.8 85.7

51-059-0030 Franconia Fairfax County VA 80.1 85.4

51-059-1005 Annandale Fairfax County VA 82.1 82.7

51-059-5001 McLean Fairfax County VA 74.3 77.7

51-107-1005 Ashburn Loudoun County VA 75.6 80.4

51-153-0009 Long Park 

Prince William 

County VA 72.3 75.8

51-510-0009 Alexandria Alexandria City VA 75.3 81.2

See Microsoft®Excel® spreadsheet “Appendix A to TSD for EPA-R03-OAR-2013-0132.xls” for formulas and calculations.
1

Technical Support Document for the Modeling and Weight of Evidence (WOE) Portions 

of the District of Columbia’s Ozone State Implementation Plan (SIP) Entitled “Plan to 

Improve Air Quality in the Washington, DC-MD-VA Region

May 23, 2007”

 

TSD Prepared July, 2012

Todd A. Ellsworth

Office of Air Monitoring and Analysis, 3AP40

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

____________________/S/________________________

Reviewed by Walter Wilkie, Associate Director,

Office of Air Monitoring and Analysis (3AP40)

____8/15/2012_____________

Date Signed

 
2

Technical Support Document for the Modeling and Weight of Evidence 

(WOE) Portions of the District of Columbia’s Ozone State 

Implementation Plan (SIP) Entitled “Plan to Improve Air Quality in the 

Washington, DC-MD-VA Region

May 23, 2007”

Purpose of the Technical Support Document

This Technical Support Document (TSD) describes the Environmental Protection 

Agency’s (EPA’s) evaluation of the modeling and WOE portions of The District of 

Columbia’s State Implementation Plan (SIP) entitled “Plan to Improve Air Quality in the

Washington, DC-MD-VA Region, May 23, 2007”, hereafter referred to as the D.C. Area 

SIP. The Metropolitan Washington, DC-MD-VA Ozone Nonattainment Area includes 

the Metropolitan Washington Region defined as follows: Montgomery, Prince George’s, 

Frederick, Charles, Calvert Counties in Maryland; Fairfax County, Arlington County, 

City of Alexandria, City of Falls Church, City of Fairfax, Prince William County, 

Loudoun County, City of Manassas and City of Manassas Park in Virginia; and the 

District of Columbia. Classified as a “moderate” nonattainment area, the Metropolitan 

Washington, DC-MD-VA Ozone Nonattainment Area is required to attain the NAAQS 

by June 2010, in effect, by the ozone season of 2009. 

The purpose of this TSD is to provide more detailed information than can be contained in 

the official notice published in the Federal Register. Readers who need more information 

than we provide in this TSD or want to review the modeling in more detail should read 

the above referenced ozone SIP for the Washington DC Metropolitan Area.

Introduction to the Washington D.C. Area State Implementation Plan for Ozone

The SIP for the D.C. area includes plans to reduce ozone-causing emissions for

Metropolitan Washington Area. The Plan also includes modeling that will predict 

whether the area will meet the ozone standard by the due date. This TSD reviews 

modeling and WOE portions of the D.C. Area SIP. This TSD reviews The District’s

documentation of modeling and WOE that attempts to show attainment of the eight-hour 

ozone standard by the 2009 ozone season. All of the states in the northeastern United 

States cooperated via the Ozone Transport Commission’s Modeling Committee to 

prepare the modeling that was performed by the New York State Department of 

Environmental Protection (NYSDEC) and supporting organizations.

The D.C. Area SIP makes a case that the modeling when combined with additional 

supporting analyses (Weight of Evidence) (WOE) indicates “that it is reasonable to 

assume that all the D.C area monitors will attain the current eight-hour ozone standard by 

the designated attainment date (June 2010).” 
3

What Are The Components Of A Modeled Attainment Demonstration?

Modeling Process Overview 

The OTC Modeling Committee used the Community Multi-scale Air Quality model

(CMAQ) version 4.4 as its photochemical grid model. The model uses simulations of 

chemical reactions, emission of ozone precursors and a sophisticated meteorological 

model to produce ozone concentrations over the eastern United States. The 

meteorological data used in the meteorological model was for the base year ozone season 

of 2002. The photochemical grid model was run with the base year meteorology and 

base year emissions to determine if the model performance was satisfactory. Once the 

model performance was determined to be adequate, 2009 ozone concentrations were 

modeled by running the model with projected emissions for 2009 and the original 2002 

meteorology. The meteorology was held constant so that the results of changing the 

emissions would not be influenced by changing meteorology. The EPA modeling 

guidance1recommends that states use the modeled ozone concentrations in a relative 

sense and not rely solely on the concentrations the model predicts for the attainment year 

(2009). The relative response factor (RRF) used in the modeled attainment test is 

computed by taking the ratio of the mean of the 8-hour daily maximum predictions in the 

future to the mean of the 8-hour daily maximum predictions with baseline emissions, 

over all relevant days. The base year ozone design values at each monitor are then 

multiplied by the monitor-specific RRF to produce an attainment year design value. If 

the result is less than or equal to 84 ppb, at all area ozone monitoring locations, the 

modeling system will have predicted attainment of the ozone air quality standard. 

The Regulatory Framework

Section 110 (a) (2) (k) of the Clean Air Act requires states to prepare air quality modeling 

to show how they will meet ambient air quality standards. EPA determined that areas 

classified as ‘moderate’ or above must use photochemical grid modeling or any other 

analytical method determined by the Administrator to be at least as effective to 

demonstrate attainment of the ozone health-based standard by the required attainment 

date (40 CFR 51.908, published at 70 FR 71612 on November 29, 2005). In 40 CFR 

51.903, published at 69 FR 23951 on April 30, 2004, EPA specified how areas would be 

classified with regard to the eight-hour ozone standard set by EPA in 1997. At 69 FR 

23858, on April 30, 2004, EPA followed these procedures and classified the Metropolitan 

Washington, DC-MD-VA Ozone Nonattainment Area as moderate, so they must attain 

the 1997 eight-hour ozone standard by June 2010. Since the attainment date is June 2010 

for moderate areas, states must achieve emission reductions by the ozone season of 2009 

in order for ozone concentrations to be reduced, and show attainment, during the last 

complete ozone season before the 2010 deadline. 

The modeling guidance lists nine steps for preparing modeling to demonstrate attainment 

of the ozone standard. 

1. Develop a conceptual description of the problem to be addressed.

 

1 Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals 

for Ozone, PM2.5, and Regional Haze, EPA -454/B-07-002, April 2007
4

2. Develop a modeling/analysis protocol.

3. Select an appropriate model to support the demonstration.

4. Select appropriate meteorological time periods to model.

5. Choose an appropriate area to model with appropriate horizontal/vertical resolution 

and establish the initial and boundary conditions that are suitable for the application.

6. Generate meteorological inputs to the air quality model.

7. Generate emissions inputs to the air quality model.

8. Run the air quality model with base case emissions and evaluate the performance.

 Perform diagnostic tests to improve the model, as necessary.

9. Perform future year modeling (including additional control strategies, if necessary) and

 apply the attainment test.

How Did The District Address All Of The Components Of A Modeled Attainment 

Demonstration?

The D.C. Area SIP addresses each of the elements of a modeled attainment 

demonstration as follows:

Conceptual description of the problem

A conceptual model describes how weather patterns affect the formation and transport of 

ozone, accounting for emissions and photochemistry. The D.C. Area SIP describes the 

climatology that produces high ozone concentrations in the D.C. metropolitan area. On 

warm sunny days, winds from the southwest and west blow emissions from sources of 

ozone-forming chemicals both at the surface and aloft toward the D.C. area. In addition, 

emissions from large combustion sources in the Ohio Valley and other areas are brought 

eastward by upper level winds to the east coast, augmenting the ozone formed locally. 

The conceptual model for this study was prepared by the Northeast States for 

Coordinated Air Use Management (NESCAUM) for use by the OTC member States. The 

conceptual model document, “The Nature of the Ozone Air Quality Problem in the Ozone 

Transport Region: A Conceptual Description (NESCAUM, October 2006)”, is provided

in Appendix G of the D.C. Area SIP. This document provides the conceptual description 

of the ozone problem in the OTR states, consistent with the EPA’s guidance.

Modeling/analysis protocol

The Ozone Transport Commission’s (OTC’s) Modeling Committee developed a protocol 

for modeling the ozone problem in the northeastern United States. The D.C. Area SIP

includes the modeling protocol in Appendix G. The modeling protocol adequately 

describes the plan to perform the photochemical grid modeling for use in the ozone 

attainment plans. 

The Model Used in the Attainment Demonstration

The Virginia Department of Environmental Quality (VADEQ), in consultation with The 

Maryland Department of the Environment (MDE), The District of Columbia Department 

of the Environment (DCDOE), and The Metropolitan Washington Council of 
5

Governments (MWCOG), was responsible for conducting the Community Multi-scale 

Air Quality Model version 4.4 (CMAQ) runs for the Washington, D.C. domain. CMAQ 

is an acceptable model, listed in the photochemical modeling guidance as a currently used 

photochemical grid model. EPA agrees CMAQ is appropriate for this modeling 

demonstration. VADEQ’s modeling runs were done in coordination with the Ozone 

Transport Commission’s (OTC) modeling for the 12-state Ozone Transport Region 

(OTR) and with the Association for Southeastern Integrated Planning (ASIP) modeling, 

done for the southeastern states. Modeling centers for OTC included the New York State 

Department of Environmental Conservation (NYSDEC), the University of Maryland, 

NESCAUM and VADEQ. Technical support documents for the OTC modeling 

performed for the OTR are included in Appendix G. The inputs to the model are 

described in Section 10 and Appendix G of the D.C. Area SIP.

Meteorological Time Periods Used in the Modeling

Section 10 of the D.C. Area SIP notes that the OTC Modeling Committee agreed to 

model the entire ozone season of 2002 (May 15 through September 30). Using the entire 

ozone season of 2002 covers many different kinds of ozone episodes and exceeds EPA’s 

recommendations for episode selection. 2002 was a good year to model because it was 

the base year for the attainment plans and as a whole is representative of meteorological 

conditions conducive to elevated concentrations of ozone.

Meteorological Data Used in the Air Quality Model

The OTC Modeling Committee decided to use a prognostic meteorological model that 

provides life-like meteorological inputs to the photochemical grid model. The 

Pennsylvania State University/National Center for Atmospheric Research Mesoscale

Meteorological Model (MM5) version 3.6 was chosen for the modeling analysis. MM5

provides a reasonable representation of weather conditions at the surface and aloft. A 

summary of the MM5 application is contained in Appendix G of the D.C. Area SIP. 

Domain of the Model, Horizontal/Vertical Resolution and the Initial and Boundary 

Conditions

The modeling domain extends from Maine to Florida and out in the Atlantic Ocean on 

the east and west to the Mississippi River. The size of the modeling domain was made 

large enough to include all emission sources that affect ozone formation in the 

northeastern United States. Even this boundary is defined by a larger photochemical 

modeling domain that covers much of North America. Over the northeastern United 

States, the model used 12 kilometer grid cells. The D.C. area is included in the 12 

kilometer grid cell area. The OTC Modeling Committee used a 12-kilometer grid size for 

the areas in and near its states to provide a fine enough grid resolution to adequately 

capture the ozone patterns experienced in the ozone transport region (OTR). The OTC 

Modeling Committee chose to use a 12 kilometer grid resolution based on its states’ 

experiences with the one-hour ozone attainment modeling that indicated that modeling at 

finer resolutions than 12 kilometers would not result in increased model accuracy. 

Outside the local areas the grid resolution used in the modeling is 36 kilometers. The 

selection of model domains and horizontal grid resolution was deemed acceptable to 
6

EPA. The grid resolution, modeling domain and boundary conditions are described in 

Appendix G of the D.C. Area SIP.

Vertical resolution is the number of layers and the size of each layer in the model. The 

layers in the photochemical grid model were set up to be compatible with the model that 

produced weather conditions for the photochemical grid model. The vertical resolution 

used in the modeling exercise followed EPA’s modeling guidance and represents the 

atmosphere where ozone forms and is transported. 

Emissions Used in the Air Quality Model

The emissions data for 2002 were generated by individual states within the OTR and 

assembled and processed through the Mid-Atlantic Northeast Visibility Union (MANEVU), a Regional Planning Organization (RPO). These emissions were then processed by 

NYSDEC using the SMOKE emissions processor to provide CMAQ compatible inputs. 

The 2002 emissions for the non-OTR areas within the modeling domain were obtained 

from the corresponding RPOs and were processed using SMOKE, in a manner similar to 

that of the OTR emissions.

The OTR states, through MANE-VU, contracted MACTEC Federal Programs (called 

Contractor) to develop 2009, 2012 and 2018 inventories based upon 2002 inventories that 

the states had previously developed for use in the base-year model work. The Contractor,

in consultation with the states, developed the necessary growth and control factors and 

applied to the 2002 inventory. Emissions for mobile sources and the electric energy 

generating units (EGUs) was not part of the Contractor’s effort. . To generate on-road 

mobile emissions, the states provided the Virginia Department of Environmental Quality 

(VADEQ) and the Northeast States for Coordinated Air Use Management (NESCAUM)

with appropriate MOBILE 6 input files along with the projected vehicle miles traveled 

(VMT), which was coupled with hourly “gridded temperature” information. As for the 

emissions from the EGU sector, the inter-RPO work group utilized the Integrated 

Planning Model (IPM) to develop the state and unit-level emissions. These inventories 

are identified as 2009 on the way (2009OTW), since they reflect all emission control 

measures that were promulgated or would become effective on or before 2009.

The base year emissions can be found in Chapter 3 and Appendix B of the D.C. Area SIP, 

while 2009 emissions are described in Chapter 4.

Base Case Run Model Performance Evaluation

The New York State DEC, Division of Air Resources, conducted a performance 

evaluation of the 2002 base case CMAQ simulation (May 15-September 30) on behalf of 

the OTC member States. Model evaluation followed performance statistics outlined in 

EPA modeling guidance. Highlights of this evaluation are provided in Chapter 10 of the 

D.C. Area SIP 

The model performance evaluation indicates the modeling system does an adequate job 

of estimating the eight-hour surface ozone concentrations throughout the Metropolitan 

Washington Area.
7

2009 Control Case Modeling and the Modeled Attainment Test

The photochemical grid model used with projected emissions for 2009, including 

emission changes due to regulations the states are planning to implement and expected 

growth by the 2009 ozone season. 

Chapter 6 of the D.C. Area SIP lists the emission controls included in the modeling for 

the D.C. area. 

Meteorological conditions from 2002, the same as the base case modeling, were used in 

the 2009 modeling. Using the base case meteorology allows the effect of changes in 

states’ emissions to be determined without being influenced by yearly fluctuations in 

meteorology and is consistent with EPA guidance. 

As described earlier in this TSD, the attainment test used in the D.C. area modeling 

demonstration involved the application of model-based RRFs to base year design values 

at each monitor to produce projected future year design values (2009). The projected 

2009 design values represent design values that should result from emission controls the 

District and surrounding states planned to have in place in 2009. The 2009 design values 

should be less than or equal to 84 ppb at all monitoring stations to meet the attainment 

test2. The modeling predicts that in 2009, D.C. area will not pass the attainment test since 

design values are projected to be over the 84 ppb standard at two monitors (see Table 1

below). 

Table 1 Modeling Attainment Test Using EPA Preferred Methodology

AIRS ID Site Name Jurisdiction State DVB RRF DVF

11-001-0025 Takoma District of Columbia 88.7 0.892 79

11-001-0041 River Terrace District of Columbia 89.0 0.883 78

11-001-0043 McMillan District of Columbia 92.7 0.883 81

24-009-0010 Calvert Calvert MD NA 0.836 NA

24-017-0010 Southern MD Charles MD 93.0 0.808 75

24-021-0037 Frederick Municipal

Airport

Frederick MD 87.3 0.846 73

24-031-3001 Rockville Montgomery MD 86.7 0.881 76

24-033-0002 Greenbelt Prince George's MD 94.0 0.869 81

24-033-8003 PG Equestrian 

Center

Prince George's MD 94.0 0.865 81

51-013-0020 Aurora Hills Arlington County VA 96.7 0.891 86

51-059-0005 Chantilly Fairfax County VA 87.0 0.867 75

51-059-0018 Mount Vernon Fairfax County VA 96.7 0.883 85

51-059-0030 Franconia Fairfax County VA 95.0 0.88 83

51-059-1005 Annandale Fairfax County VA 94.0 0.88 82

51-059-5001 McLean Fairfax County VA 88.0 0.883 77

51-107-1005 Ashburn Loudoun County VA 90.0 0.869 78

51-153-0009 Long Park Prince William

County

VA 85.0 0.871 74

51-510-0009 Alexandria Alexandria City VA 90.0 0.883 79

 

2 The guidance also states that additional analyses are recommended to determine if attainment will be 

likely, even if the modeled attainment test is “passed”. The guidance recommends supplementary analyses 

in all cases, and specifically recommends a WOE analysis if modeled ozone is greater than or equal to 82 

ppb.
8

Summary of Photochemical Grid Modeling Results

In summary, the basic photochemical grid modeling contained in D.C. Area SIP meets 

EPA’s guidelines and when used with the methods recommended in EPA’s modeling 

guidance, is acceptable to EPA. Applying EPA’s preferred methodology to CMAQ 

model results, the future design values for 2009 shown in Table 10-5 indicate only two 

monitors will be at or slightly above 84 parts per billion (ppb). All other monitors 

(sixteen) will be below 85 ppb. These results place the Washington, DC-MD-VA region 

well within EPA’s range, 82-87 ppb, where WOE will contribute significantly to the 

region’s attainment demonstration3.

Weight of Evidence Demonstration

EPA’s modeling guidance describes how to use a photochemical grid model and 

additional analytical methods to complete a WOE analysis to estimate if emissions 

control strategies will lead to attainment of the eight-hour NAAQS for ozone. A WOE 

analysis is a supporting analysis that helps to determine if the results of the 

photochemical modeling system are correctly (or not correctly) predicting future air 

quality. 

The WOE portion of the D.C. Area SIP describes the analyses performed, databases used, 

key assumptions and outcomes of each analysis, and why the evidence, viewed as a 

whole, supports a conclusion that the Washington, DC-MD-VA ozone nonattainment 

area will attain the NAAQS despite the model prediction that some monitors’ future 

design values exceed the current eight-hour ozone standard.

Table 2 outlines under what circumstances a WOE demonstration is needed. Modelpredicted design values are summarized above in Table 1. Of the twenty-two (18) ozone 

monitors in the Washington, DC-MD-VA region only four (4) exceed the threshold (82 

ppb) where the EPA modeling guidance recommends a WOE demonstration. All four of 

the monitors fall within the 82-87 ppb threshold outlined in Table 1.

The WOE analysis for the remaining seven monitors includes the following:

 A comparison of predicted 2009 ozone design values and current projected design 

values for 2006, 

 An analysis of recent ozone trends in the Philadelphia nonattainment area,

 Alternative methods for calculating the 2009 ozone design value,

 An analysis of model-predicted regional transport,

 University of Maryland’s analysis of model sensitivity to emission changes.

 

3 Guidance on the Use of Models and Other Analyses in Attainment Demonstrations for the 8-hour Ozone 

NAAQS, EPA-454/R-05-002, October 2005, “Table 2-1: Guidance for Weight of Evidence 

Determinations,” p. 9.
9

Table 2. EPA Guidelines for Supplemental Analyses and Weight of Evidence 

Determinations

Results of Modeled Attainment Test Supplemental Analyses

Future Design Value < 82 ppb, all 

monitor sites

Basic supplemental analyses should be 

completed to confirm the outcome of the 

modeled attainment test

Future Design Value 82 - 87 ppb, at 

one or more sites/grid cells

A weight of evidence demonstration 

should be conducted to determine if 

aggregate supplemental analyses support 

the modeled attainment test

Future Design Value > 88 ppb, at one 

or more sites/grid cells

More qualitative results are unlikely to 

support a conclusion differing from the 

outcome of the modeled attainment test.

Design Value Trends

The D.C. Area SIP states that there have been significant declines in the Washington 

D.C. nonattainment area’s eight-hour ozone design values over the last several decades. 

Significant declines did occur after enactment of the NOx SIP Call in the 2003/2004 

period. The data in Table 4 show that ozone design values have decreased sharply after

2003. EPA’s study of the effect of the NOx SIP Call has documented the beneficial 

effects of the NOx SIP Call emission reductions that were in place by the 2004 ozone 

season across the eastern United States 

Since 2004, design values have continued to decrease and the area began monitoring 

attainment in 2009 as shown in Table 3 below. Ozone design values have generally 

continued to decrease since the 2009 ozone season and the area continues to be in 

attainment of the 1997 8-hour ozone standard. 

Table 3. Recent Ozone Design Value Trends (PPM)

Site 

Name

AIRS 

ID

2003 2004 2005 2006 2007 2008 2009 2010 2011

Takoma 11-001-0025 0.088 0.085 0.078 0.080 0.081 0.080 0.077 0.075 0.075

River 

Terrace

11-001-0041 0.092 0.084 0.077 0.079 0.085 0.086 0.078 0.077 0.076

McMillan 11-001-0043 0.094 0.089 0.082 0.085 0.087 0.087 0.080 0.079 0.079

Southern 

MD 

24-017-0010 0.094 0.091 0.088 0.085 0.085 0.082 0.075 0.075 0.077

Frederick 

Municipal

Airport

24-021-0037 0.088 0.083 0.078 0.080 0.083 0.082 0.076 0.075 0.076

Rockville 24-031-3001 0.088 0.083 0.080 0.083 0.086 0.084 0.078 0.074 0.076

PG 

Equestrian 

Center

24-033-8003 0.099 0.094 0.091 0.091 0.091 0.087 0.078 0.077 0.079

Aurora 

Hills

51-013-0020 0.099 0.095 0.087 0.086 0.087 0.085 0.079 0.079 0.080

Chantilly 51-059-0005 0.089 0.084 0.079 0.078 0.078 0.079 0.073 0.067 0.061

Mount 

Vernon

51-059-0018 0.097 0.096 0.091 0.090 0.089 0.087 0.080 0.074 0.068

Franconia 51-059-0030 0.097 0.096 0.089 0.089 0.086 0.085 0.080 0.081 0.082

Annandale 51-059-1005 0.095 0.094 0.086 0.087 0.084 0.083 0.078 0.068 0.061

McLean 51-059-5001 0.088 0.086 0.079 0.084 0.083 0.083 0.077 0.066 0.059

Ashburn 51-107-1005 0.092 0.088 0.080 0.080 0.082 0.083 0.077 0.075 0.073

Long Park 51-153-0009 0.087 0.083 0.079 0.079 0.078 0.078 0.071 0.070 0.069

Alexandria 51-510-0009 0.092 0.088 0.081 0.081 0.083 0.081 0.075 0.074 0.077
10

Summary of EPA’s Evaluation D.C. Area SIP’s WOE Analysis

The reduction in ozone precursor emissions, coupled with current ozone design values 

that show attainment of the 1997 8-hour ozone NAAQS, confirms the D.C. Area SIP’s 

assertion that the Metropolitan Washington, DC-MD-VA Ozone Nonattainment Area was

in compliance with the 1997 8-hour ozone NAAQS by the attainment date. 

Summary of EPA’s Technical Findings

The result of the photochemical grid modeling analysis using EPA’s recommended 

methods predicts that the Metropolitan Washington, DC-MD-VA Ozone Nonattainment 

Area the 1997 8-hour ozone standard by the attainment date. This result is confirmed by 

the monitored air quality data presented in Table 3.

Recommendation of Approval of Attainment Demonstration

EPA has carefully evaluated the information provided by D.C. Area Ozone SIP and 

concludes that the attainment demonstration satisfies all of EPA’s requirements. EPA 

therefore, recommends approval of the attainment demonstration. 
SUBJECT: Technical Support Document — District of Columbia, Maryland, and Virginia;

2002 Base Year Emissions Inventory, Reasonable Further Progress Plan,Contingency Measures, Reasonably Available Control Measures, and

Transportation Conformity Budgets for the Metropolitan Washington, DC 1997 8-Hour Ozone Moderate Nonattainment Area

FROM: Maria A.’Pino, Senior Air Quality Planning Specialist

Office of Air Program Planning

TO: File (2J 2sJ//ITHRU: Cristina Fernandez, Associate Directof

Office of Air Program Planning

This document provides a technical review of revisions to the District of Columbia,

Maryland, and Virginia State Implementation Plans (SIPs) for the Washington, DC-MD-VAmoderate 1997 8-hour ozone nonattainment area (the Washington Area). The District of

Columbia Department of the Environment (DDOE), the Maryland Department of the

Environment (MDE), and the Virginia Department of Environmental Quality (VADEQ) worked

together to develop a joint plan for the Washington Area to address emissions inventory,

reasonable further progress (RFP), reasonably available control measures (RACM) analysis, andRFP contingency measure requirements for the 1997 8-hour ozone national ambient air quality

standard (NAAQS). This plan, entitled “Plan to Improve Air Quality in the Washington, DCMD-VA Region, State Implementation Plan (SIP) for 8-Hour Ozone Standard, Moderate AreaSIP,” will be referred to as “the Washington Area 8-hour ozone plan” throughout this document.

The Washington Area 8-hour ozone plan was submitted to the Environmental Protection Agency

(EPA) as a SIP revision by DDOE on June 12, 2007, by MDE on June 4, 2007, and by VADEQ

on June 12, 2007. These SIP revisions also establish a motor vehicle emissions budget (MVEB)

for 2008 for the Washington Area.I. BACKGROUND

A. General Requirements

Section 182 of the Clean Air Act (CAA) and s 1997 8-hour ozone regulations (40

CFR 51.910) require each moderate and above 8-hour ozone nonattainment area to submit an

emissions inventory and RFP SIP revision that describes how the area will achieve actual

emissions reductions of volatile organic compounds (VOC) and nitrogen oxides (NOx) from a
Specifically, section 1 72(c)( 1) states the following: “Such plan provisions shall provide for the

implementation of all reasonably available control measures as expeditiously as practicable

(including such reductions in emissions from existing sources in the area as may be obtained

through the adoption, at a minimum, of reasonably available control technology) and shall

provide for attainment of the national primary ambient air quality standards.” Control measuresthat would advance the attainment date are considered RACM and must be included in the SIP.

RACM are necessary to ensure that the attainment date is achieved “as expeditious as

practicable.”

Phase 1 of the 8-hour ozone implementation rule, published on April 30, 2004 (69 FR

23951), set out criteria for classifying nonattainment areas under the 1997 8-hour ozone standard.The Phase 1 rule also addressed revocation of the 1-hour NAAQS; how anti-backsliding

principles will ensure continued progress toward attainment of the 8-hour ozone NAAQS;attainment dates; and the timing of emissions reductions needed for attainment. On November29, 2005, EPA published the Phase 2 final rule for implementation of the 8-hour standard. ThePhase 2 rule addressed the RFP control and planning obligations as they apply to areasdesignated nonattainment for the 1997 8-hour ozone NAAQS (70 FR 71612). The Phase 2 final

rule was revised on June 8, 2007 (72 FR 31727). Among other things, the Phase 1 and 2 rules

outline the SIP requirements and deadlines for various requirements in areas designated asmoderate nonattainment. The rules set a due date ofJune 15, 2007 for the required base yearemission inventory, RFP plan, modeling and attainment demonstration, RACM, MVEB, and

contingency measures (40 CFR 51.908(a)).

Section 182(b)(1) ofthe CAA and EPA’s 1997 8-hour ozone implementation rule (40

CFR 51.910) require each 8-hour ozone nonattainment area designated moderate and above to

submit for review and approval into its SIP an emissions inventory and RFP plan that describes

how the area will achieve actual emissions reductions of VOC and NOx from a baselineemissions inventory. For a moderate 8-hour ozone nonattainment area with an attainment datemore than 5 years after designation, a 15 percent RFP reduction in ozone precursor emissions is

required within 6 years (2002-2008). For a moderate area with an approved 15 percent rate-ofprogress (ROP) plan under the 1-hour standard, states can use reductions from VOC or NOx or acombination of either. For a moderate area without and approved ROP plan, a 15% reduction inVOC is required. The reductions may come from anywhere within the 8-hour nonattainmentarea. Table 1 outlines these requirements.

2
anywhere within the 8

hour

nonattainment area.

In addition, RFP plans must include contingency measures, which are additional controls

that would be implemented ifthe area fails to make reasonable further progress. $ CAA

section 172(c)(9). Implementation of these measures would provide additional emissions

reductions of up to 3 percent ofthe adjusted base year inventory (or lesser percentage that willmake up the identified shortfall). RFP plans must also include a MVEB, which is the allowableon-road mobile emission an area can produce and continue to demonstrate RFP. 40 CFR 93.

B. The Washington Area

In 1997, EPA revised the health-based NAAQS for ozone, setting it at 0.08 parts per

million (ppm) averaged over an 8-hour time frame. EPA set the 8-hour ozone standard based on

scientific evidence demonstrating that ozone causes adverse health effects at lower ozone

concentrations and over longer periods oftime, than was understood when the pre-existing

1-hour ozone standard was set. EPA determined that the 8-hour standard would be more

protective of human health, especially children and adults who are active outdoors, and

individuals with a pre-existing respiratory disease, such as asthma.

On April 30, 2004 (69 FR 23951), EPA finalized its attainment/nonattainment

designations for areas across the country with respect to the 8-hour ozone standard. These

actions became effective on June 15, 2004. Among those nonattainment areas is the Washington

Area. This Washington Area includes the District of Columbia (the District); Arlington, Fairfax,

Loudoun, and Prince William Counties and the cities of Alexandria, Fairfax, Falls Church,

Manassas, and Manassas Park in Virginia (the Northern Virginia area) and Calvert, Charles,

Frederick, Montgomery, and Prince George’s Counties in Maryland. Pursuant to Phase 1 of the

8-hour ozone implementation rule, an area was classified under Subpart 2 ofthe CAA based on

its 8-hour design value ifthat area had a 1-hour design value at or above 0.121 ppm (the lowest

1-hour design value in Table 1 of Subpart 2). Based on this criterion, the Washington Area was

classified under Subpart 2 as a moderate nonattainment area. See 40 CFR 81.309, 81.321 and

8 1.347.

II. EVALUATION OF STATE SUBMITTAL

A. Base Year Emissions Inventory

An emissions inventory, required by section 172(c)(3) of the CAA, is a comprehensive,

3
must cover emissions on an annual basis and also for on a typical ozone season day basis. Theinventories for RFP and attainment demonstration planning are computed based on a “typical”ozone season day.

DDOE, MDE and VADEQ (the States) along with the Metropolitan Washington Council

of Governments (MWCOG) worked together to develop a 2002 base year inventory for theWashington Area. This inventory is found in Chapter 3 and Appendix B ofthe Washington Area

8-hour ozone plan. A summary ofthe Washington Area 2002 base year VOC and NOx

emissions inventory is included in Tables 2a and 2b, below.

Table 2a. Washington Area 2002 Base Year VOC Emissions in Tons per Day (tad)

Source Category District of Maryland Virginia Source Category

Columbia Totals

Point 0.24 4.6 8.07 12.91

Area 16.81 92.49 83.35 192.64

Nonroad Mobile 8.91 63.82 53.06 125.79

On-road Mobile 13.09 56.13 47.71 116.94

Total (excluding biogenics) 39.05 217.04 192.19 448.28

Biogenic Emissions 13.63 166.7 134.41 314.74

Total 52.68 383.74 326.6 763.02

Table 2b. Washington Area 2002 Base Year NOx Emissions in Tons per Day (tpd)

District of . . . Source Category Source Sector . Maryland Virginia Columbia Total

Point 4.89 155.78 59.93 220.6

Area 2.16 6.77 15.32 24.25

Nonroad Mobile 10.54 34.21 40.97 85.72

On-road Mobile 23.7 132.27 110.68 266.65

Total (excluding biogenics) 41.29 329.03 226.9 597.22

Biogenic Emissions 0.1 1.75 1.22 3.07

Total 41.39 330.78 228.12 600.29

EPA Region III’s Air Quality Analysis Branch (AQAB) reviewed the 2002 base year

inventory for the Washington Area using the appropriate EPA policy and guidance. Please see

the attached “Technical Support Document (TSD) for the Emission Inventories for the

Washington DC-MD-VA 8 Hour Ozone State Implementation Plan (SIP) Base Year Inventory,”

prepared by Janet C. Kremer and signed by Walter Wilkie, Air Quality Analysis Branch Chief,

on February 4, 2009 (Washington Area Emission Inventory TSD). As discussed in detail in the

4
(

)(

) 

has been determined to be the 2002 adjusted base year inventory. Sections 182(b)(1)(B) and (D)

require the exclusion from the base year inventory of emissions benefits resulting from the

Federal Motor Vehicle Control Program (FMVCP) regulations promulgated by January 1, 1990and the Reid Vapor Pressure (RVP) regulations promulgated June 11, 1990 (55 FR 23666). The

FMVCP and RVP emissions reductions are determined by the state using EPA’s on-road mobilesource emissions modeling software, MOBILE6. The FMVCP and RVP emission reduétions are

then removed from the base year inventory by the state, resulting in an adjusted base year

inventory. The emission reductions needed to satisfy the RFP requirement are then calculatedfrom the adjusted base year inventory. These reductions are then subtracted from the adjusted

base year inventory to establish the emissions target for the RFP milestone year (2008).

For moderate areas like the Washington Area, the CAA specifies a 15 percent reduction

in ozone precursor emissions over an initial 6-year period. In the Phase 2 Rule (70 FR 71612),

EPA interpreted this requirement for areas that were also designated nonattainment and classified

as moderate or higher for the 1-hour ozone standard. In the Phase 2 Rule, EPA provided that an

area classified as moderate or higher that has the same boundaries as an area, or is entirelycomposed ofseveral areas or portions of areas, for which EPA fully approved a 15 percent plan

for the 1-hour NAAQS, is considered to have met the requirements ofsection 1 82(b)( 1) ofthe

CAA for the 8-hour NAAQS. In this situation, a moderate nonattainment area is subject to RFP

under section 1 72(c)(2) of the CAA and shall submit, no later than 3 years after designation for

the 8-hour NAAQS, a SIP revision that meets the requirements of 40 CFR 51.910(b)(2). The

RFP SIP revision must provide for a 15 percent emission reduction (either NOx andlor VOC)accounting for any growth that occurs during the 6-year period following the baseline emissionsinventory year, that is, 2002-2008.

The Washington nonattainment area under the 1-hour ozone standard was classified as

severe. For the 1-hour ozone NAAQS, EPA fully approved the 15% ROP plans for theWashington, DC 1-hour severe ozone nonattainment area on August 5, 1999 (64 FR 42600), July

19, 2000 (65 FR 44686), and October 6, 2000 (65 FR 59727). Therefore, according to the Phase

2 Rule, the RFP plan for the Washington Area may use either NOx or VOC emissions reductions

(or both) to achieve the 15 percent emission reduction requirement.

According to section 1 82(b)( 1 )(D) of the CAA, emission reductions that resulted from the

FMVCP and RVP rules promulgated prior to 1990 are not creditable for achieving RFP emission

reductions. Therefore, the 2002 base year inventory must be adjusted by subtracting the VOC

and NOx emission reductions that are expected to occur between 2002 and the future milestone

years due to the FMVCP and RVP rules.

5
CAA measures turned off. Any other local inputs for vehicle inspection and maintenance(JIM) programs should be set according to the program that was required to be in place in

1990. Fuel RVP should be set at 9.0 or 7.8 depending on the RVP required in the local area

as a result of fuel RVP regulations promulgated in June 1990.

C) Calculate the difference between 2002 and 2008 VOC emissions factors calculated in Step B

and multiply by 2002 vehicle miles traveled (VMT). The result is the VOC emissions

reductions that will occur between 2002 and 2008 without the benefits of any post-1990 CAAmeasures. These are the non-creditable VOC reductions that occur over this period.

Calculate the difference between 2002 and 2008 NOx emissions factors calculated in Step B

and multiply by 2002 VMT. This result is the NOx emissions reductions that will occur

between 2002 and 2008 without the benefits of any post-1990 CAA measures. These are the

non-creditable NOx reductions that occur over this period.

D) Subtract the non-creditable VOC reductions calculated in Step C from the actual

anthropogenic 2002 VOC inventory estimated in Step A. Subtract the non-creditable NOx

reductions calculated in Step C from the actual anthropogenic 2002 NOx inventory estimated

in Step A. These adjusted VOC and NOx inventories are the basis for calculating the target

level of emissions in 2008.

E) The target level of VOC and NOx emissions in 2008 needed to meet the 2008 ROP

requirement is any combination of VOC and NOx reductions from the adjusted inventoriescalculated in Step D that total 18 percent. For example, the target level of VOC emissions in2008 could be a 10 percent reduction from the adjusted.

The States sets out the calculations for the adjusted base year inventory and 2008 RFP targetlevels in Section 5 of the Washington Area 8-hour ozone plan.

A) The Washington Area 2002 anthropogenic base year inventory is found in Table 5-1 ofthe

Washington Area 8-hour ozone plan, and is summarized in Table 3, below.

Table 3. Washington Area 2002 Anthronoenic Base Year Inventory (Ozone Season tnd)

Source Category VOC NOx

Point 12.91 220.6Area 192.64 24.25

Nonroad 125.79 85.72

On-Road 116.94 266.65

Total 448.28 597.22

6
(i) 2002 On

Road 166.55 308.24

(ii) 2008 On-Road 154.10 276.63

Non-creditable Reductions (i) — (ii) 12.45 31.61

D & E) The State’s calculations ofthe Washington Area 2002 VOC inventory adjusted to 2008

and the VOC target level for 2008 are found in Table 5-5 ofthe Washington Area 8-hour

ozone plan, and are summarized in Table 5, below.

Table 5. Washington Area 2008 RFP Target Level Calculations (Ozone Season tpd)

Description Formula VOC

A 2002 Rate-Of Progress Base Year Inventory 448.28

B FMVCP/RVP Reductions Between 2002 And 2008 12.45

C 2002 Adjusted Base Year Inventory Relative To 2008 A -B 435.83

D FP Ratio 15%

E missions Reductions Required Between 2002 & 2008 C * D 65.37

F rarget Level for 2008 C -E 370.45

Please note that the States elected to RFP in the Washington Area using only VOC reductions.

As explained in Section A.I ofthis document, this is allowable. A moderate 8-hour ozonenonattainment area with and approved 15 percent ROP plan under the 1-hour standard can usereductions from VOC or NOx or a combination of either.C. Projected Inventories and Determination of RFP

The States describes their methods used for developing its 2008 projected VOC and NOx

inventories in Section 4.0 of the Washington Area 8-hour ozone plan. Projected uncontrolledand controlled 2008 VOC and NOx emissions are found Tables 4-5 and 4-6 ofthe Washington

Area 8-hour ozone plan. EPA Region III’s AQAB reviewed the procedures used to develop itsprojected inventories and found them to be reasonable. Please see the attached Washington Area

Emission Inventory TSD.

Projected controlled 2008 emissions for the Washington Area are summarized in Table 4-

9 and 4-10 ofthe Washington Area 8-hour ozone plan. The data from Tables 4-9 and 4-10 is

presented in Table 6, below.

7
Mobile 70.98 160.30

Total 358.84 493.22

To determine if 2008 RFP is met in the Washington Area, the total projected controlled

emissions must be compared to the target levels calculated in the previous section ofthisdocument. As shown below in Table 7, the total VOC emission projections meet the 2008 RFP

emission target. Therefore, the 2008 RFP in the Washington Area is demonstrated.Table 7. Determination of whether RFP is met in 2008 in the Washington Area

.

. VOC Emissions Description (tpd)

A Total 2008 Projected Controlled Emissions 358.84B Target Level for 2008 370.45

R1?PmetifA<B Yes

D. Control Measures and Emission Reductions for RFP

The control measures the States took credit for in order to meet the RFP requirement in the

Washington Area are described in Section 6.0 of the Washington Area 8-hour ozone plan. To

meet the RFP requirement for the Washington Area, the States used a combination of area sourcecontrol, nonroad mobile, and on-road mobile measures.

1. Area Source Measures

. Mobile Repair and Refinishing

This rule establishes VOC limits for paints using in mobile repair and refinishing. The VOClimits are consistent with federal limits for mobile equipment refinishing materials. The rulealso requires improved transfer efficiency application equipment, enclosed spray gun cleaning,

and minimal training. This rule applies to all manufacturers of paints used in mobile repairand refinishing and operators of mobile repair and refinishing facilities.

• Portable Fuel Containers Rule, Phase I

This measure introduces performance standards for portable fuel containers and spouts, and is

intended to reduce emissions from storage, transport and refueling activities. The rule alsoincluded administrative and labeling requirements.

8
Consumer and commercial products are items sold to retail customers for household, personal

or automotive use, along with the products marketed by wholesale distributors for use in

institutional or commercial settings such as beauty shops, schools, and hospitals. VOC

emissions result from the evaporation ofsolvent contents in the products or solvents used as

propellants. This measure requires the reformulation of certain consumer products to reducetheir VOC content.

• Solvent Cleaning Operations Rule

This rule establishes hardware and operating requirements and alternative compliance optionsfor vapor cleaning machines used to clean metal parts. These machines are used in

manufacturing operations to clean grease, wax, oil and other contaminants from parts when a

high level or cleanliness is necessary. The rule also affects cold cleaners, which are used in

automobile and maintenance facilities and industrial maintenance shops. The rule applies toall counties in the nonattainment area.

• Reformulated Consumer Products Rule (Consumer and Commercial Products), Phase II

Phase II ofthe Consumer and Commercial Products Rule contains more stringent VOCcontent limits than the existing federal consumer products nile. The rule also contains

requirements for labeling and reporting. Manufacturers of various specialty chemicals named

in the rule, such as aerosol adhesives, floor wax strippers, dry cleaning fluids and general

purpose cleaners are affected by this rule.

Area Source 2008 Emission Reductions: 30.98 tpd VOC and 0 tpd NOx.

2. Nonroad Measures — NONROAD Model

The States calculated the emission reductions for 2008 RFP using the EPA NONROAD

model for the following measures:

• Non-Road Gasoline Engines Rule -Phase I and II Emissions Standards for Gasoline-Powered

Nonroad Utility Engines

This federal measure established emissions for small nonroad, spark-ignition (i.e., gasolinepowered) utility engines. The measure affects gasoline-powered (or other spark-ignition) lawn

and garden equipment, construction equipment, and other utility equipment rated at or below

19 kilowatts (an equivalent of 25 or fewer horsepower). Phase 2 ofthe rule applied further

controls on handheld and non-handheld outdoor equipment. (See 60 FR 34581, 65 FR 24267,and 64 FR 15207.)

9
• Emissions Standards for Spark Ignition Marine Engines

This federal measure controls exhaust emissions from new spark-ignition gasoline marine

engines, including outboard engines, personal watercraft engines, and jet boat engines. Once

the program is fully implemented, manufacturers ofthese engines must demonstrate to EPAthat hydrocarbon emissions are reduced, by 75% from present levels, by testing enginesrepresentative of the product line before sale and after use. (See 61 FR 52087.)

• Emissions Standards for Large Spark Ignition Engines

This federal measure controls VOC and NOx emissions from several groups of previouslyunregulated nonroad engines, including large industrial spark-ignition engines, recreational

vehicles, and diesel marine engines. The emission standards apply to all new engines sold inthe United States and any imported engines manufactured after these standards begin.

Controls on the category oflarge industrial spark-ignition engines are first required in 2004.

Controls on the other engine categories are required beginning in years after 2005. (See 67

FR 68241.)

• Reformulated Gasoline Use in Nonroad Motor Vehicles and Equipment

This federally mandated measure requires the use of lower polluting “reformulated” gasolinein the Washington Area. See “Reformulated Gasoline in On-road Vehicles,” above. This

measure affects the various nonroad mobile sources that bum gasoline, such as lawn mowers,

trimmers, generators, and compressors. The program has been in place in the Washington

Area since 1995.

Nonroad Mobile 2008 Emission Reductions (NONROAD Model): 36.91 tpd VOC and

11.68 tpd NOx.

As discussed in the Washington Area Emission Inventory TSD, EPA Region III’s AQAB

reviewed the procedures that the State’s used to develop its projected inventories, including theuse of the NONROAD model, and found them to be reasonable.

3. Other Nonroad Measures

• Standards for Locomotives

This national measure establishes emission standards for newly manufactured and

remanufactured diesel-powered locomotives and locomotive engines. This regulation took

effect in 2000. (See 63 FR 18998.)

10
High-Tech Vehicle Inspection and Maintenance (Enhanced I/M)

The CAA requires enhanced J/M programs in serious, severe, and extreme ozone

nonattainment areas, metropolitan statistical areas (MSA), and consolidated MSA (CMSA)portions ofthe Ozone Transport Region (OTR) with urbanized populations over 200,000.Enhanced JIM was required in the Washington 1-hour ozone nonattainment area. That

requirement is still in place due to the anti-backsliding provisions of CAA section 110(1). InMaryland and the District of Columbia, emissions tests are performed at test-only stations.

Virginia tests vehicles in stations that may also perform repairs using a decentralized program.

• Federal Tier I Vehicle Emission Standards and New Federal Evaporative Test Procedures

The CAA required cleaner federal motor vehicle emissions standards (Tier I standards)

beginning with model year 1994. The CAA also requires a uniform level of evaporativeemission controls, which are more stringent than most evaporative controls used in older

vehicles. These federally implemented programs affect light duty vehicles and trucks. See 40

CFR Part 86.

• National Low Emission Vehicle (NLEV) Program

The NLEV program is a vehicle technology program that provides light duty vehicles and

trucks that are significantly cleaner than pre-1998 models. The National LEV program was

developed through an unprecedented, cooperative effort by the northeastern states, auto

manufacturers, environmentalists, fuel providers, EPA, and other interested parties. NationalLEV vehicles are 70% cleaner than 1998 models. The National LEV program will result in

substantial reductions in VOCs and NOx. The States have adopted the NLEV program and

EPA approved the States’ programs into their SIPs. (See 64 FR 72564 and 65 FR 44981.)

• Tier 2 Vehicle Standards

This federal measure set emissions standards for all passenger vehicles, including sport utility

vehicles (SUVs), minivans, vans and pick-up trucks. These regulations also require lowerlevels of sulfur in gasoline. The new tailpipe standards are set at an average standard of 0.07grams per mile for NOx for all classes of passenger vehicles beginning in 2004. (See 65 FR6697.)

• Heavy Duty Diesel Engine (HDDE’) Rule

This federal program affects heavy-duty diesel engines in trucks. Under the HDDE rule, truck

manufacturers must comply with more stringent tailpipe standards for NOx and hydrocarbons

starting in 2004. (See 62 FR 54694.)

11
5. Transportation Control Measures (TCMs) and Vehicle Technology, Fuel, orMaintenance Measures

Section 108(f) ofthe CAA provides examples of TCMs that can be implemented to reduce

emissions from mobile sources. Most TCMs are designed to reduce vehicle miles traveled or

vehicle trips or improve the flow oftraffic. In conjunction with state departments oftransportation and local transit authorities, the States identified a number of projects designed toreduce vehicle travel and mitigate traffic congestion in the Washington Area. These measures

include purchase of alternative-fueled vehicles, improvements to bicycle and pedestrian facilities,

and improvements to transit services and access to transit facilities. Additional information onTCMs is contained in Appendix F ofthe Washington Area 8-hour ozone plan.

TCM and Vehicle Technology, Fuel and Maintenance Measures 2008 Emission Reductions:

0.19 tpd VOC and 0.49 tpd NOx.

6. Voluntary Bundle

States can take credit for emission reductions from voluntary measures pursuant to EPA’sSeptember 2004 and August 2005 policy memoranda, “Incorporating Emerging and Voluntary

Measures in a State Implementation Plan (SIP)” and “Guidance on Incorporating Bundled

Measures in a State Implementation Plan.” The States developed a set of measures for thevoluntary bundle that includes new measures as well as some voluntary measures from the

Washington Area 1-hour ozone SIP. The States included an estimate of the emission reductions

from the voluntary measures in Appendix H of the Washington Area 8-hour ozone plan.

Voluntary Bundle 2008 Emission Reductions: 0.19 tpd VOC and 0.28 tpd NOx.

7. RFP Emission Reduction Summary

While many ofthe emission control measures used to meet RFP also resulted in NOx emission

reductions, the States elected to meet RFP in the Washington Area using only VOC reductions.

Table 8 summarizes the VOC emission reductions that the States claimed in the Washington

Area 8-hour ozone plan to meet RFP in the Washington Area.

12
Onroad Measures (TCMs) 0.19

Voluntary Bundle 0.19Total 74.32

E. Contingency Measures for Failure to Meet RFP

Section 1 72(c)(9) ofthe CAA requires a state with a moderate or above ozone

nonattainment area to include sufficient additional contingency measures in its RFP plan in casethe area fails to meet RFP. The same provision ofthe CAA also requires that the contingencymeasures must be fully adopted control measures or rules. Upon failure to meet an RFPmilestone requirement, the state must be able to implement the contingency measures without

any further rulemaking activities. Upon implementation ofsuch measures, additional emissionreductions of at least 3 percent of the adjusted 2002 baseline emissions must be achieved. For

more information on contingency measures, see the April 16, 1992 General Preamble (57 FR

13512) and the November 29, 2005 Phase 2 8-hour ozone implementation rule (70 FR 71612).

1. Requirements and Target Calculations

To meet the requirements for contingency emission reductions, EPA allows states to use

NOx emission reductions to substitute for VOC emission reductions in their contingency plans.

However, the States chose to use only VOC reductions to meet the contingency measurerequirement in the Washington Area. The States discuss the Washington Area contingency

measures for failure to meet RFP in Section 11 ofthe Washington 8-hour ozone plan. The States

calculated the contingency VOC reduction for the Washington Area as shown in Table 9, below.

The RFP contingency requirement may be met by including in the RFP plan a demonstration of

18 percent VOC & NOx RFP. The additional 3 percent reduction above the 15 percent

requirement must be attributed to specific measures.

13
.FP Emissions Reductions Required Between 2002 & 65 37 E2008 C*D 0

F Contingency Percentage 0.3% 2.7%

1.31 15.27

0 Contingency Emission Reduction Requirements C * F

H Contingency Measure Target Level for 2008 C- E- G 369.15 550.34

2. VOC Contingency Measures

• Portable Fuel Containers Rule, Phase I and Phase II

This measure introduces performance standards for portable fuel containers and spouts, and isintended to reduce emissions from storage, transport and refueling activities. The rule alsoincluded administrative and labeling requirements.

2008 VOC Emission Reductions: 1.31 tpd

3. NOx Contingency Measures

• Clean Air Interstate Rule (CAIR)

CAIR requires NOx and S02 emission reductions from large fossil fuel-fired electricgenerating units. The rule is set up in several phases with the first phase ofNOx reductions to

come by 2009. EPA approved Virginia CAIR program into the Virginia SIP in 2007 (72 FR73602). EPA put a Federal Implementation Plan (FTP) in place for the District in 2006 (71

FR 25328). On July 11, 2008, the DC Circuit Court issued its decision to vacate and remand

both CAIR and the associated CAIR FIPs (North Carolina v. EPA, 531 F.3d 836 (DC Cir.,2008). However, in response to EPA’s petition for rehearing, the court issued an order

remanding CAIR to EPA without vacating either CAIR or the CAIR FIPs (North Carolina v.

EPA, 550 F.3d 1176 (DC Cir., 2008)). The court, thereby, left CAIR in place in order to“temporarily preserve the environmental values covered by CAIR” until EPA replaces it with

a rule consistent with the court’s opinion (id. at 1178). Because CAIR has been remanded to

EPA without vacatur, CAIR and CAIR FIPs are currently in effect in Virginia and the District.

• Maryland’s Healthy Air Act (HAA)

The HAA requires reductions in NOx, SO2, and mercury emissions from Maryland’s largestand oldest coal fired power plants. EPA approved the HAA into Maryland’s SIP in 2008.(See 73 FR 51599.)

2008 NOx Emission Reductions: 15.3 tpd (total)

(DC: 0.66 tpd; MD: 12.19 tpd; VA: 2.45 tpd)

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g

, 

g

y 

q

g

Area.

Table 10. Evaluation of the Washington Area 2008 RFP Contingency MeasureRequirement

Description VOC NOx

(tpd) (tpd)

A Total 2008 Projected Controlled Emissions 358.84 493.22B Contingency Measure Target Level for 2008 369.15 550.34Contingency measure requirement met if A < B Yes Yes

F. RACM Analysis and Determination

1. RACM Requirement

Pursuant to section 172(c)(1) ofthe CAA, states are required to implement all RACM as

expeditiously as practicable for each nonattainment area. Specifically, section 1 72(c)( 1) states

the following: “In general—Such plan provisions shall provide for the implementation of allreasonably available control measures as expeditiously as practicable (including such reductionsin emissions from existing sources in the area as may be obtained through the adoption, at a

minimum, of reasonably available control technology) and shall provide for attainment ofthenational primary ambient air quality standards.” Furthermore, in EPA’s Phase 2 Rule, EPAdescribes how states must include a RACM analysis with their attainment demonstration (70 FR71659). The purpose ofthe RACM analysis is to determine whether or not reasonably availablecontrol measures exist that would advance the attainment date for nonattainment areas. Control

measures that would advance the attainment date are considered RACM and must be included inthe SIP. RACM are necessary to ensure that the attainment date is achieved “as expeditious as

practicable.” RACM is defined by the EPA as any potential control measure for application topoint, area, on-road and nonroad emission source categories that meets the following criteria:

• The control measure is technologically feasible;• The control measure is economically feasible;

• The control measure does not cause “substantial widespread and long-term adverse

impacts;’’

• The control measure is not “absurd, unenforceable, or impracticable;” and

• The control measure can advance the attainment date by at least one year.

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• be enforceable;• be technically feasible;• be economically feasible (proposed as a cost of $3,500-$5,000 per ton or less);

• not create substantial or widespread adverse impacts within the region; and• reduce emissions from the source being controlled more than the de minimis threshold,

proposed as 0.1 tons per day.As stated in section 7.1.8 ofthe Washington Area 8-hour ozone plan, preliminary

modeling results indicate that any RACM would need to collectively reduce NOx and/or VOC

emission by more than 20 to 40 tpd by the 2008 ozone season in order to advance the attainmentdate by one year.

The States evaluated 322 potential stationary, area, nonroad, and mobile source control

measures against the RACM criteria. Several measures would have provided some emissionreductions. However, the States determined that none ofthe mandatory measures would achievereductions in the 2008 ozone season. In addition, the States determined that the total reductionsfrom these measures would be less than 20 to 40 tpd. Therefore, the States concluded that thereare no RACM appropriate to advance the Washington Area’s attainment date.

3. EPA Evaluation

EPA has reviewed the States’ analysis. To meet the RACM requirement, the States must

demonstrate that it has adopted all RACM necessary to move the Washington Area towardattainment as expeditiously as practicable and to meet all RFP requirements. As demonstratedabove in section IV ofthis document, the States have met the RFP requirements for theWashington Area.

The States evaluated all source categories that could contribute meaningful emission

reductions, and compiled an extensive list of potential control measures. Furthermore, the States

considered the time needed to develop and adopt regulations and the time it would take to see the

benefit from these measures. While the States found that the measures could not be used to

advance the Washington Area’s attainment date, the State’s determined that many ofthe

measures were useful and would be considered for future SIPs for the Washington Area.Therefore, EPA concurs with the States’ conclusion that there are no RACM that would haveadvanced the 2010 attainment date for the Washington Area.

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for conformity purposes are outlined in 40 CFR 93.11 8(e)(4). The process for determining the

adequacy ofsubmitted SIP budgets is described in 40 CFR 93.118(f).

States must establish VOC and NOx MVEBs for each ofthe milestone years up to the

attainment year and submit the mobile budgets to EPA for approval. Upon adequacydetermination or approval by EPA, states must conduct transportation conformity analysis for

their Transportation Improvement Programs (TIPs) and long range transportation plans to ensure

highway vehicle emissions will not exceed relevant MVEBs. Failure of demonstrating such

transportation conformity lapses resulting in freezing offederal highway funds and all federal

highway projects in the lapsed area.

The States discuss transportation conformity in Section 8.0 of the Washington Area 8-

hour ozone plan. The States describe their methods and provide detailed input parameters used inmodeling the inventories in Appendices El and E2 ofthe Washington Area 8-hour ozone plan. In

the Washington Area, the Metropolitan Washington Air Quality Committee (MWAQC) consultswith the Transportation Planning Board (TPB) to establish mobile source emissions budgets.

The MWCOG Transportation Planning Department calculated the 2008 mobile emissions

inventory using EPA’s MOBILE6.2 and the Travel Demand Model Version 2.ld#50 with 2005

vehicle registration data. The Washington Area MVEB for the 2008 RFP is based on the

projected 2008 mobile source emissions accounting for all mobile control measures. (See Table6, “Washington Area 2008 Projected Controlled VOC & NOx Emissions (tpd).”) The budgetsare equal to the projected 2008 on-road mobile source emission inventories minus reductions

from transportation control measures. The States also established MVEBs for 2009, but EPA is

not evaluating that budget in this document.

The MVEBs for the 2008 RFP are shown in Table 11, below.

Table 11. Washington Area 2008 RFP MVEBs

VOC (tpd) NOx (tpd)

(A) Projected Controlled Mobile Emissions 70.98 160.30(B) Transportation Control Measures 0.19 0.49(A)-(B) 70.79 159.81

MVEB (rounded to nearest 0.1 tpd) 70.8 159.8

For budgets to be approvable, they must meet, at a minimum, s adequacy criteria (40

CFR 93.11 8(e)(4)). In a September 4, 2009 Federal Register notice, EPA notified the public that

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MVEBs to be reasonable. Because the 2008 RFP MVEBs are adequate for transportation

conformity purposes and the methods the States used to develop them are correct, the 2008 RFP

budgets are approvable.

III. SUMMARY AND RECOMMENDATIONS:

The EPA Region III Air Protection Division (APD) has reviewed the States’ 2008 RFP

plan, contingency measures for failure to meet RFP, and RACM analysis for the Washington Area

and found them to be approvable. In addition, EPA Region III’s AQAB determined that the

States used acceptable techniques and methodologies to develop the Washington Area 2002 base

year emission and 2008 milestone year projected inventories. Furthermore, APD has found the

Washington Area’s 2008 REP MVEBs adequate for transportation conformity purposes.

Therefore, APD recommends approval of the following SIP elements in the Washington Area 8-

hour ozone plan: the 2002 base year emissions inventory, the RFP plan and associated 2008

projected emission inventories, the RACM analysis, the contingency measures for failure to meet

2008 RFP, and the 2008 MVEBs for the Washington, DC-MD-VA moderate nonattainment area.

Attachments: - “Technical Support Document (TSD) for the Washington, DC-MD-VA Nonattainment Area:

8 Hour Ozone State Implementation Plan (SIP) Attainment Demonstration and Base Year

Inventory,” prepared by Janet C. Kremer and signed by Walter Wilkie, Air Quality Analysis

Branch Chief, on February 4, 2009 (Washington Area Emission Inventory TSD).

- “Adequacy Status of the Metropolitan Washington DC Area (DC—MD—VA) Area 8-Hour

Ozone Non-Attainment Area’s Reasonable Further Progress Plan Vehicle Emission Budgets

for Transportation Conformity Purposes” (74 FR 45853). -_ .____.

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