Docket ID: EPA‐R06‐OAR‐2012‐0099

Technical Support Document ‐ A

Addressing

Emissions Inventory and Reasonable Further Progress Plan for the  

Dallas/Fort Worth Serious 8‐Hour Ozone Nonattainment Area

March 2014

This is the Environmental Protection Agency’s (EPA’s) technical review of a revision to

the Dallas/Fort Worth (DFW) State Implementation Plan (SIP) submitted by the Texas

Commission on Environmental Quality (TCEQ) on January 17, 2012, to address emissions

inventory (EI) and reasonable further progress (RFP) requirements for the 1997 8‐hour ozone

National Ambient Air Quality Standard (NAAQS or standard) for the serious ozone

nonattainment area. The SIP revision also establishes motor vehicle emissions budgets (MVEBs)

for 2011 and 2012. The TCEQ’s submittal, including appendices, is provided in the docket for

this rulemaking.

Within this technical support document (TSD), “we,” “us,” and “our” means the EPA.

A. Background

The TCEQ has been addressing ground level ozone in the DFW area for over two

decades. To wit, the counties of Collin, Dallas, Denton, and Tarrant (the “core” counties) were

initially designated and classified as a moderate nonattainment area under the 1‐hour ozone

standard (November 6, 1991, 56 FR 56694). The area did not attain the 1‐hour standard at the

end of 1996 and was reclassified as a serious ozone nonattainment area (February 18, 1998, 63

FR 8128). The DFW area attained the 1‐hour ozone standard in 2006 (73 FR 61357, October 16,

2008) and has continued to meet that standard.

On April 30, 2004, the EPA designated the DFW area (consisting of Collin, Dallas,

Denton, Ellis, Johnson, Kaufman, Parker, Rockwall and Tarrant counties) as a moderate

nonattainment area under the 1997 8‐hour ozone standard, with an attainment date of June

15, 2010.1 However, the DFW area failed to attain the 1997 ozone standard by June 15, 2010,

and was reclassified as a serious ozone nonattainment area (see 75 FR 79302, December 20,

2010).2 Section 182 of the Clean Air Act (CAA or Act) and EPA’s 1997 8‐hour ozone regulations

(40 CFR 51.910) require each moderate and above 8‐hour ozone nonattainment area to submit

an EI and RFP SIP revision, to account for how the area will achieve specific emissions

 

1 We refer to the DFW nonattainment area for the 1997 ozone standard as, “the nine‐county nonattainment area.”

The nine‐county nonattainment area consists of the four core counties and five “cradle” counties. The cradle

counties are Ellis, Johnson, Kaufman, Parker and Rockwall, and in prior SIP actions, we referred to these as “the

five new counties.” Since these counties are no longer new to the nonattainment designation, and geographically

they “cradle” the four core counties, we are adopting the term “cradle” herein for ease of identification. 2

On April 30, 2012, the EPA made designations under the 2008 ozone standard (77 FR 30088, May 21, 2012). In

that action, the EPA designated Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant and Wise

counties as a moderate ozone nonattainment area. The submittals under evaluation in this TSD do not address the

2008 ozone standard, but will provide progress toward meeting this newer standard.
2

reductions over a specified period of time. The EI is an estimation of actual emissions of air

pollutants in an area and for this RFP, we are focusing on emissions of nitrogen oxides (NOx)

and volatile organic compounds (VOC), which are precursors to ozone formation. On October 7,

2008 (73 FR 58475), we approved the RFP for the DFW moderate ozone nonattainment area,

which demonstrated required emissions reductions through the end of calendar year 2008 and

MVEBs for 2008. Pursuant to section 182(c)(2)(B)(i) of the Act, the RFP SIP for the DFW serious

nonattainment area must demonstrate emissions reductions of at least three percent per year,

for each of the calendar years 2009 ‐ 2012. The emissions must occur within the nine‐county

nonattainment area. The starting point for calculating the emissions reductions, also called the

“base year,” is 2002, as approved in the prior RFP (73 FR 58475).

In addition, the RFP plan must include contingency measures, which are additional

controls that would be implemented if the area should fail to make reasonable further progress

(see section 172(c)(9) of the Act). Implementation of these measures would provide additional

emissions reductions of up to three percent of the adjusted base year inventory (or a lesser

percentage that will make up the identified shortfall). The RFP plan must also include MVEBs,

which are the allowable on‐road mobile emissions an area can produce and continue to

demonstrate RFP. EPA’s regulations concerning MVEBs are found at 40 CFR 93.118.

Table 1 below identifies the EIs, rate of progress (ROP)3 and RFP SIPs approved by EPA

for the DFW area.

Table 1: DFW Emissions Inventories, ROP and RFP SIPs

SIP Revision Federal Register Citation

1‐Hour Ozone Standard; Emissions Inventory 11/8/1994, 59 FR 55589

1‐Hour Ozone Standard; 15% VOC ROP Plan 5/22/1997, 62 FR 27964

1‐Hour Ozone Standard; Post 1996 ROP Plan 4/12/2005, 70 FR 18993

8‐Hour Ozone Standard; Emissions Inventory 8/15/2008, 73 FR 47835

8‐Hour Ozone Standard; 15% RFP, MVEBs and Revised EI 10/7/2008, 73 FR 58475

B. The State’s Submittals and EPA’s Analysis

We reviewed the Texas submittal for consistency with the requirements of the CAA and

EPA guidance and regulations.

1. Base Year Emissions Inventory

The 2002 base year EI is the starting point for calculating the reductions necessary to

meet the RFP requirements of the CAA. Section 172 (c)(3) and 182(b)(1) of the CAA require that

nonattainment plan provisions include an inventory of actual NOx and VOC emissions from all

sources in the nonattainment area. On January 17, 2012, TCEQ submitted a revised 2002 base

year EI to EPA as part of the RFP SIP revision for the DFW serious 8‐hour ozone nonattainment

area. A 2002 base year EI was approved in 2008 (73 FR 58475) and since that time,

 

3 ROP means for purposes of the 1‐hour ozone NAAQS, the progress reductions required under section 172(c)(2)

and sections 182(b)(1), 182(c)(2)(B), and 182(c)(2)(C) of the CAA. See 40 CFR 51.900(q).
3

improvements in estimating and calculating emissions have been made. The revisions to the

2002 EI include all area, point, non‐road mobile, and on‐road mobile source emissions in the

nine‐county nonattainment area. The specific revisions to the 2002 EI are described below:

Area Source Emissions

Area sources are small scale industrial, commercial and residential sources that

generate emissions, such as gas stations, bakeries, and solvent use (e.g., dry cleaners, auto

paint shops, print shops and house paints). Area sources are numerous and their emissions are

calculated as county‐wide totals rather than as individual facilities. These emissions are typically

estimated by multiplying an established emission factor (emissions per unit of activity) by the

appropriate activity or activity surrogate responsible for generating emissions. Population is

one of the more commonly used activity surrogates for area sources. An example of actual

activity data is the amount of gasoline sold in an area.

The revised 2002 area source EI was developed by using the 2008 National Emissions

Inventory (NEI) data and calculating back to 2002, using factors based on the EPA’s Economic

Growth Analysis System (EGAS), version 5.0. This process is called “back‐casting.” 2008 was

chosen as the year for back‐casting because it was the most recent and complete set of NEI

data available at the time the TCEQ developed the DFW Serious RFP plan.

As in Tables 2 and 3 below, the revised 2002 area source EI for NOx and VOC increase by

1.59 tons per year (tpy) and 9.62 tpy, respectively. We find the approach and method of

calculating the 2002 area source EI satisfactory and the emissions increases to be acceptable.

Point Source Emissions

Point sources are individually inventoried and usually located at a fixed, stationary

location. Examples include large industrial facilities, like cement plants and electric power

plants. Point sources are required to submit emissions data to TCEQ annually. The data are

reviewed by the TCEQ for quality assurance purposes and stored in the State of Texas Air

Reporting System (STARS) database. Point source EI data for 2002 was obtained from STARS on

September 15, 2010. There were no significant changes to these data from when they were

reported in 2008 (73 FR 58475).

Non‐road Emissions

Non‐road mobile sources generally include industrial and construction equipment; lawn,

garden and agricultural equipment; aircraft/airport equipment; locomotives; and marine

vessels and equipment. A Texas‐specific version of the EPA’s latest NONROAD 2008a model,

called the Texas NONROAD (TexN) model, was used to calculate emissions from the non‐road

mobile sources, with the exception of aircraft/airport, locomotives and oilfield drilling rigs. The

TexN model uses local survey data for categories including diesel construction equipment;

liquid propane gas powered forklifts; transportation refrigeration units; commercial lawn,

garden and agricultural equipment; and recreational marine vessels.

Airport emissions were calculated using the Federal Aviation Administration’s Emissions

and Dispersion Modeling System (EDMS) version 5.1. The EDMS integrates all airport emissions

sources (mobile and stationary) into a single model. The mobile source emissions include the
4

medium and larger aircraft, ground support equipment, and auxiliary power units. Data for air

taxis, general aviation, and military aircraft were gathered from the 2008 NEI.4 Actual local

activity data for 2002 was used to update the 2002 base year; 1999 data had been used in the

prior RFP (73 FR 58475).

Locomotive emissions were updated with data from a 2010 study, which is included in

Appendix 6 of the state’s RFP submittal. In the 2010 study, annual and daily inventories were

developed for every year between 1990 and 2040. The updates include use of fuel consumption

data from the Burlington Northern Santa Fe and Union Pacific railroads, and use of the US

Department of Transportation’s Bureau of Transportation Statistics for fuel data for all other

rail companies in the nine‐county nonattainment area. The emission factors were updated

using tier‐level distributions5 and EPA fleet‐average emission factors.

Emissions were developed for oil and gas drilling rig diesel engines to provide a more

accurate inventory. The drill rig EI is provided in Appendix 7 of the State’s submittal.6

The use of relatively recent local survey data provides a more accurate representation

of non‐road emissions in the DFW area. Detailed descriptions of the non‐road data and

calculations are provided in Appendices 4‐7 of the State’s submittal. As shown in Tables 2 and 3

below, the revised 2002 non‐road EI for NOx is shown to increase by 18.74 tpy and for VOC

there is a decrease of 37.55 tpy. We believe the revised data are more accurate and find these

changes acceptable.

On‐road Emissions

On‐road emissions sources include automobiles, trucks and motorcycles ‐ vehicles

commonly driven on roadways. The TCEQ revised the on‐road mobile emissions by using more

current (2002, 2008 and 2010) vehicle registration data collected from the Texas Department of

Transportation. In addition, the TCEQ expanded the area’s travel demand model (TDM) to fully

incorporate Ellis, Johnson, Kaufman and Parker counties and to include Hood, Hunt and Wise

counties. A travel demand model includes elements such as roadway and transit networks, and

population and employment data to calculate the expected impacts of roadway vehicle

volumes and transit route ridership. The TDM was updated using 2004 data, replacing the 1999

data used in the prior RFP (73 FR 58475) and also incorporating data from more recent public

transportation surveys.7 The TCEQ used the EPA’s Motor Vehicle Emissions Simulator (MOVES)

model, version 2010a. Local data were used to improve the accuracy of the model, including

vehicle speeds for each roadway link; temperature; humidity; vehicle age distributions and

 

4 An air taxi is a small commercial aircraft used for brief flights between places that do not have regularly

scheduled flights. 5

For example, line haul engines manufactured from 1993 to 2004 are Tier 1 and may not exceed 7.4 grams per

brake horsepower hour (g/bhp‐hr) of NOx. Tier 2 for line haul engines, manufactured from 2005 – 2011 may not

exceed 5.5 g/bhp‐hr of NOx. Switcher engines are subject to similar standards. The newest line haul and switcher

engines have even lower emissions. 6 The drill rig EI was erroneously included in Appendix 3 (for area sources); the TCEQ has identified these emissions

as being in the non‐road mobile source category. 7 These include the 2007 Dallas Area Rapid Transit Onboard Survey and the 2008 Fort Worth Transit Authority and

Denton County Transportation Authority Onboard Survey.
5

percentage of miles traveled for each vehicle type; type of inspection and maintenance

program; fuel control programs; and gasoline vapor pressure controls.

Sections 182(b)(1)(C) and (D) of the Act require that the base year inventory exclude the

emissions that would be eliminated by the Federal Motor Vehicle Control Program (FMVCP)

regulations promulgated by January 1, 1990, and the Reid Vapor Pressure (RVP) regulations (55

FR 23666, June 11, 1990), which require maximum RVP limits in nonattainment areas during

the peak ozone season. The FMVCP and RVP emissions reductions can be determined using

EPA’s MOVES, which estimates emissions from cars, trucks and motorcycles. These emission

reductions are subtracted from the base year inventory resulting in an “adjusted” base year

inventory. The on‐road emissions estimates are further described in Chapter 2 and Appendix 1

of the TCEQ submittal.

Detailed descriptions of the on‐road data and calculations are provided in Appendix 8 of

the State’s submittal. As shown in Tables 2 and 3 below, the revised 2002 on‐road EI for NOx

and VOC decrease, by 2.22 tpy and 21.9 tpy, respectively. We believe the revised data are more

accurate and find these changes acceptable.

Revised Base Year EI for 2002

The previously approved base year EI (73 FR 58475) is provided in Table 2 below, for

reference and the revised 2002 base year EI is provided in Table 3. As a reminder and as

allowed by rule, the TCEQ chose to base the previously approved 15% plan on NOx reductions

for the four core counties, and as required, VOC reductions in the five cradle counties (see 40

CFR 51.910(a)(1)(iii)(B)(1) and (2), 40 CFR 51.910(b)(2)(ii), and 73 FR 58475).

We find the methodologies used to update the 2002 base year EI acceptable and

recommend approval of the revised 2002 base year EI.

Table 2: Previously Approved RFP Base Year EI (73 FR 58475)

2002 Base Year Inventory, reported in tons per year (tpy)

Source Type NOx VOC

4 Core

Counties

5 Cradle

Counties

9 County

Total

4 Core

Counties  

5 Cradle

Counties

9 County

Total

Point 34.55 44.70 79.25 18.73 7.69 26.42

Area 34.96 2.08 37.04 205.07 32.34 237.41

On‐road

Mobile

296.01      60.22 356.23 143.28 18.32 161.60

Non‐road

Mobile

117.22 17.45 134.67 108.63 10.97 119.60

Total 482.74 124.45 607.19 475.71 69.32 545.03

   
6

Table 3: Revised RFP Base Year EI proposed for approval in this action

2002 Base Year Inventory (tpy)

Source Type NOx VOC

4 Core

Counties

5 Cradle

Counties

9 County

Total

4 Core

Counties

5 Cradle

Counties

9 County

Total

Point 34.57 44.67 79.24 18.76 7.67 26.43

Area 35.34 3.29 38.63 214.45 32.58 247.03

On‐road

Mobile

291.90 62.11 354.01 119.69 20.01 139.70

Non‐road

Mobile

124.72 28.69 153.41 73.23 8.82 82.05

Total 486.53 138.76 625.29 426.13 69.08 495.21

2. Adjusted Base Year Inventories, Required Reductions and Target Level Emissions

Section 182 of the CAA and 40 CFR 51.910 require that the three percent emissions

reduction (per year) is calculated from the base year EI. The required reductions are then

subtracted from the adjusted base year EI to provide the emissions target numbers.

Table 4 below provides the 2011 adjusted base year EIs and Table 5 provides the

adjusted base year EIs for 2012.

Table 4: 2011 RFP Adjusted Base Year Inventory (tpy)

Source Type NOx VOC

Point 79.24 26.43

Area 38.63 247.03

Non‐road Mobile 153.41 82.05

On‐road Mobile8 354.56 122.16

Total 625.84 477.67

   

 

8 The Adjusted EI for the on‐road category varies from the base EI because there is fleet turnover for Tier 0

vehicles. Tier 0 emissions were effective in model years 1981‐1993.
7

Table 5: 2012 RFP Adjusted Base Year Inventory (tpy)

Source Type NOx VOC

Point 79.24 26.43

Area 38.63 247.03

Non‐road Mobile 153.41 82.05

On‐road Mobile* 359.18 126.46

Total 630.46 481.97

In calculating the RFP target levels, section 182(c)(2)(C) of the CAA and EPA’s NOx

Substitution Guidance (issued by EPA’s Office of Air Quality Planning and Standards, 1993),9

allow NOx emissions reductions (or controls) to be substituted for VOC controls if such would

maximize reductions in ozone air pollution. The TCEQ established long ago that DFW area

ozone levels are sensitive to NOx emissions. When we say “sensitive” to NOx (or “NOx‐

limited”), we mean that decreases in NOx emissions are more effective in lowering the area's

ozone design value than reductions of VOC emissions. Modeling performed by TCEQ in 2011

indicates that ozone formation in the DFW area is still generally NOx sensitive: for similar

reductions of NOx (78 tpd) and VOC (80 tpd), the DFW 8‐hour ozone design value would be

reduced significantly more from NOx emissions (‐3.43 ppb) than VOC (‐0.12 ppb).10 Therefore,

the state has chosen to provide only NOx emissions reductions from inside the 9‐county

nonattainment area to meet the 2011 and 2012 RFP targets or milestones.

Tables 6 and 7 below provide an accounting of the required emissions reductions

through 2008, 2011 and 2012, and the target emissions levels of NOx and VOC for 2011 and

2012. For reductions through 2008 the TCEQ provided NOx reductions for the four core

counties and VOC reductions in the five cradle counties (73 FR 58475); we’ve shown these

reductions in Table 6 below, using the revised 2002 base year EI. Table 7 shows the reductions

required through 2012 for the nine‐county nonattainment area.

Table 6: Calculation of NOx and VOC Reductions through 2008 (tpd)

Description NOx in 4 Core

Counties

VOC in 5 Cradle

Counties

a. 2002 Emissions Inventory 486.53 69.08

b. Non‐creditable reductions through 2008   ‐  3.09    2.23

c. 2002 adjusted to 2008 (a‐b) 489.62 66.85

d. 15% reductions required through 2008 (0.15 x c)   73.44 10.03

   

 

9 Please see http://www.epa.gov/ttn/caaa/t1/memoranda/noxsubst.pdf. 10 For more detail on the emission reduction efficiency for NOx and VOC in the DFW area, see Appendix 9 of the

State’s submittal.
8

Table 7: Calculation of NOx and VOC Target Levels of Emissions through 2012 (tpd)

Description 9‐county area

NOx VOC

a. 2002 Emissions Inventory 625.29 495.21

b1. Non‐creditable reductions, 2002 – 2011 (FMVCP + RVP)   ‐  0.5511    17.5312

b2. 15% reductions required through 2008    73.44    10.03

b3. 9% reductions required through 2011    56.33  ‐‐ 

c. 2002 Adjusted to 2011 [a‐(b1+b2+b3)], or 2011 Target 496.07 467.65

d1. Non‐creditable reductions for 2012 (FMVCP + RVP)  ‐   4.62   ‐  4.30

d2. 3% Reductions required for 2012    18.91  ‐‐ 

e. 2002 Adjusted to 2012 [c‐(d1+d2)], or 2012 Target 481.78 471.95

3. Control Measures

The control measures that achieved the necessary emission reductions to meet the RFP

requirements are discussed in Chapter 4 of the Texas submittal. The majority of point source

reductions came from NOx controls at electric generating units in the four core counties (65 FR

53172, September 1, 2000). Area source VOC controls included expanding the surface coating

rule and the Stage I gasoline controls into the five cradle counties (71 FR 3009, January 19,

2005). Non‐road emissions reductions were a result of implementing federal measures such as

the standards for non‐road spark‐ignition (SI) engines, heavy duty non‐road engines, Tier 1, 2,

and 3 non‐road diesel engines, and Tier I and II locomotive NOx standards. Reduction in on‐road

mobile source emissions came from the inspection and maintenance (I/M) program, gas cap

pressure test, a two‐speed idle test for heavy duty gas vehicles, reformulated gasoline, the

FMVCP, and the National Low Emissions Vehicle (NLEV) program. The control measures relied

upon to meet the area’s RFP requirements and associated emissions reductions are listed

below in Tables 8‐10. The State rules relied on in this plan have all been approved in prior

actions, as identified below, in the far right column in each of Tables 8‐10. The approval dates

and citations for the federal rules implemented and listed below were too many to list herein

but are available at www.epa.gov/otaq/standards/index.htm.

EPA has reviewed the controls and projected emission reductions and determined that

they are acceptable.

   

 

11 Texas RFP submittal: Chapter 2, Table 2‐11 and Appendix 1, Sheets 12, 13, 37 and 38. 12 Texas RFP submittal: Chapter 2, Table 2‐12 and Appendix 1, Sheets 12, 13, 37 and 38.
9

Table 8. NOx Control Measures and Expected Emission Reductions (tpd), 2002‐2012

Control Strategy Description 2002‐

2008

2008‐

2011

2011‐

2012

Approval Date

EGU NOx Control 35.93 7.14 0.15 9/1/2000

65 FR 53172

FMVCP, I/M, Reformulated Gasoline and on‐

road Texas Low Emission Diesel (TxLED)13

396.98 113.84 40.39 I/M: 11/14/2001

66 FR 57261

Tier I and II Locomotive NOx Standards 8.11 1.14 2.25   

Small non‐road SI Engines (Phase I)  ‐2.62  ‐0.49  ‐0.06   

Heavy Duty Non‐road Engines 17.51 1.98 0.82   

Tier 2 and 3 Non‐road Diesel Engines 12.73 7.27 2.34   

Small Non‐road SI engines (phase II) 1.66 0.43 0.07   

Large Non‐road SI & Recreational Marine 12.92 7.07 2.50   

Non‐road TxLED 5.64 0.15  ‐0.02 see footnote 12

Non‐road RFG  ‐0.71  ‐0.11 0.00   

Non‐road locomotive and TERP14 0.65 2.26 0.00   

Tier 4    0.59 1.21   

Small SI (Phase III)    0.42 0.37   

Chapter 117 NOx area source engines    128.14 6.13   

Drilling rig low emission diesel    1.16  ‐0.08   

Total Reductions Projected   488.80 270.99 56.07

   

 

13 The TxLED fuel rules apply to highway (on‐road) and non‐road vehicles and were approved into the Texas SIP on

November 14, 2001 (66 FR 57196). Subsequent revisions were approved April 6, 2005 (70 FR 17321), October 6,

2005 (70 FR 58325), October 24, 2008 (73 FR 63378), and May 6, 2013 (78 FR 26255). 14 The Texas Emission Reduction Plan (TERP) was approved as an economic incentive program on November 14,

2001 (66 FR 57160). A revision allowing the State to capture credit from TERP reductions and use such in

attainment demonstrations for certain areas was approved August 19, 2005 (70 FR 48647). A revision to provide

credit for emissions reductions from TERP in the DFW area was approved on January 14, 2009 (74 FR 1903).
10

Table 9. VOC Control Measures and Expected Emission Reductions (tpd), 2002‐2012

Control Strategy Description 2002‐

2008

2008‐

2011

2011‐

2012

Approval Date

Portable Fuel Containers 1.86 2.09 0.74 2/10/2005

70 FR 7042

Surface Coating/Printing (Point Sources) 0.15 0.01 0.00 1/19/2006

71 FR 3009

FMVCP, I/M, Reformulated Gasoline and on‐

road TxLED

157.39 46.83 14.90 I/M: 66 FR 57261

TxLED: footnote 12

Tier I and II Locomotive NOx Standards 0.12 0.06 0.14   

Small non‐road SI Engines (Phase I) 28.07 1.56 0.54   

Heavy Duty Non‐road Engines 4.58 0.72 0.23   

Tier 2 and 3 Non‐road Diesel Engines 3.30 1.06 0.34   

Small Non‐road SI engines (phase II) 22.67 4.75 0.85   

Large Non‐road SI & Recreational Marine 6.38  ‐5.91 10.29   

Non‐road RFG 3.87 0.49 0.11   

Small SI (Phase III) 0.45 2.46 2.63   

Tier 4    0.05 0.10   

Total Reductions Projected   228.84 54.17 30.87   

Table 10. NOx and VOC Control Measures and Expected Emission Reductions for 2013

Control Strategy Description NOx (tpd) VOC (tpd) Approval Date

FMVCP, I/M, Reformulated Gasoline and on‐

road TxLED

33.22 10.01 I/M: 66 FR 57261

TxLED: footnote 12

Tier I and II Locomotive NOx Standards 0.53 0.05   

Small non‐road SI Engines (Phase I)  ‐0.06 0.55   

Heavy Duty Non‐road Engines 0.74 0.22   

Tier 2 and 3 Non‐road Diesel Engines 2.16 0.32   

Small Non‐road SI engines (phase II) 0.07 0.72   

Large Non‐road SI & Recreational Marine 2.42 1.18   

Non‐road TxLED 0.41 0.00 TxLED: footnote 12

Non‐road RFG  ‐0.01 0.08   

Small SI (Phase III) 0.37 2.37   

Tier 4 1.75 0.12   

Total Reductions Projected for 2013 41.60 15.6215

   

 

15 The Texas RFP submittal indicates that 15.67 tpd in VOC are expected however, their worksheets in Appendix 1

of the submittal indicate 15.62 tpd. In fact, 15.62 tpd is the sum of the emissions provided in the worksheets.
11

4. Demonstration of the RFP

As discussed above, the DFW RFP must provide at least 3% emissions reductions each

year, through the attainment year. In order to show that the reductions associated with the

control measures are adequate to meet the percent reduction requirements, the 2002 base

year emissions are projected to 2011 and 2012. The total of VOC and NOx emissions in the

projected inventories must be equal to or less than the target inventories (listed at lines c and e

in Table 7, above). Texas developed the projected inventories for 2011 and 2012 by first

estimating growth and then calculating the reductions from the control measures listed in

Tables 7 and 8 above. Texas used the Economic Growth Analysis System (EGAS) emissions

activity forecast software model to estimate economic, industrial, and population growth

factors. EGAS provides State and local governments with an EPA‐approved set of emissions

activity growth factors.

Tables 11 and 12 below show summaries of the emissions reductions through 2011 and

2012 and demonstrate how the area will meet the RFP targets for those years.

Table 11. Summary of RFP Demonstration for DFW through 2011 (tpd)

Inventory NOx VOC

2011 Target 496.07 467.65

2011 Uncontrolled Emissions 1168.59 823.46

Projected Emission Reductions through 2011 759.79 283.01

2011 Projected Emissions after RFP Reductions 408.80 540.45

RFP Met? Yes No

Surplus 87.27   

Shortfall    72.80

In Table 11 above, we see that the NOx surplus of 87.27 tpd is approximately 18% over

the target of 496.07 tpd. The VOC shortfall of 72.80 tpd is approximately 16% under the target

of 467.65 tpd. The NOx surplus is greater than the VOC shortfall and would therefore offset the

shortfall. In the RFP submittal, Texas notes they are “reserving” 77.29 tpd of the surplus NOx

reductions (approximately 16%) to offset the VOC shortfall. This illustrates that the emissions

reductions projected for 2011 are sufficient to meet the 2011 target.

Table 12. Summary of RFP Demonstration for DFW through 2012 (tpd)

Inventory NOx VOC

2012 Target 481.78 471.95

2012 Uncontrolled Emissions 1194.94 846.38

Projected Emission Reductions through 2012 815.86 313.88

2012 Projected Emissions after RFP Reductions 379.08 532.50

RFP Met?   Yes No

Surplus 102.70   

Shortfall    60.55
12

In Table 12 above, the NOx surplus of 102.70 tpd is approximately 21% over the target

of 481.78 tpd. The VOC shortfall of 60.55 tpd is approximately 13% under the target of 471.95

tpd. The NOx surplus is greater than the VOC shortfall. In the RFP submittal, Texas notes they

are “reserving” 61.86 tpd of the surplus NOx reductions (approximately 13%) to compensate for

the VOC shortfall. This illustrates that the emissions reductions projected for 2012 are sufficient

to meet the corresponding target.

Chapter 3 and Appendix 1 of the State’s submittal provide the methodology and

calculations used to determine the target emission levels and demonstrate RFP. We find that

the State’s RFP demonstration for the DFW area is in accordance with EPA guidelines (see

Appendix A of the Phase 2 rule to implement the 8‐hour ozone standard, November 29, 2005,

70 FR 71612, p. 71696).

5. Contingency Provisions

For ozone nonattainment areas classified as moderate or above, states must include in

their submittal contingency measures to be implemented if the area fails to make reasonable

further progress (CAA sections 172(c)(9) and 182(c)(9)). The contingency measures should, at a

minimum, ensure that an appropriate level of emissions reductions continue to be made if

attainment or RFP are not achieved. The EPA interprets the Act to require states with moderate

and above ozone nonattainment areas to include sufficient contingency measures so that, upon

implementation of such measures, additional reductions of up to 3 percent of the emissions in

the adjusted base year EI would be achieved in the year following the year in which the failure

has been identified. Contingency measures could include federal measures and local measures

already scheduled for implementation, as long as their emission reductions are beyond those

needed for attainment or to meet RFP. The CAA does not preclude a state from implementing

such measures before they are triggered. For more information on contingency measures see

the April 16, 1992 General Preamble (57 FR 13498, 13511) and the Phase 2 rule (70 FR 71612).

Texas will use emissions reductions in excess of those needed for RFP as the

contingency measures (see Chapter 4, pages 12 and 13 of the State’s submittal). Table 13 below

summarizes the emissions reductions used for contingency measures.

Table 13. Summary of RFP Demonstration for DFW, Contingency Measures (tpd)

Description NOx VOC

A. 2002 Emission Inventory adjusted to 2012 630.46 481.97

B. 3% needed for contingency (630.46 x 0.03) 18.91 0.00

Excess reductions to meet contingency requirement    

C. Margin of safety, reserved as needed for 2012 MVEB  ‐17.16 0.00

D. Total Reductions Projected for 2013 (from Table 10 above) 41.60 15.62

Total surplus or shortfall    

E. Total RFP contingency reductions available (add lines C and D) 24.44 15.62

Line E is larger than line B. Subtract line B from line J for surplus 5.53 15.62

Is the contingency measure requirement met? Yes Yes
13

Table 13 above shows that the NOx reductions projected for 2013 are sufficient to meet the

requirement for contingency measures. Note that VOC reductions are not necessary for this

contingency demonstration, but those projected (15.62 tpd) are greater than what would be

needed for contingency (481.97 x 0.03 = 14.46).  

6. Motor Vehicle Emissions Budget

The 1997 8‐hour ozone RFP plan must include MVEBs for transportation conformity

purposes. The MVEB is the mechanism to determine if the future transportation plans conform

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

quality violations, worsen existing violations, delay RFP milestones, or delay timely attainment

of the NAAQS. A MVEB is the maximum amount of emissions allowed in the SIP for on‐road

motor vehicles The MVEB establishes an emissions ceiling for the regional transportation

network. The DFW RFP SIP contains VOC and NOx MVEBs for the RFP milestone years 2011 and

2012 and these are provided in Table 14 below. On‐road emissions must be shown in future

transportation plans to be less than the MVEBs for 2011, 2012, and subsequent years.

We found the 2011 and 2012 RFP MVEBs (also termed transportation conformity

budgets) adequate, and on February 27, 2012, the availability of these budgets was posted on

our website for the purpose of soliciting public comments. The comment period closed on

March 28, 2012, and we received no comments. On February 1, 2013, we published the Notice

of Adequacy Determination for these RFP MVEBs (78 FR 7429). Once determined adequate,

these RFP budgets must be used in future DFW transportation conformity determinations. The

adequacy determination represents a preliminary finding by EPA of the acceptability of the

MVEB. Today we are finding the MVEBs are fully consistent with RFP, and the RFP plan is fully

approvable, as it sets the allowable on‐road mobile emissions the DFW area can produce and

continue to demonstrate RFP.

Table 14. RFP Motor Vehicle Emissions Budgets for DFW (tpd)

Year NOx VOC

2011 197.05 89.54

2012 195.39 82.20

D. Summary and Recommendations  

The TCEQ used acceptable techniques to revise the base year EI and calculate the 2011

and 2012 target EIs, the emissions reductions for the milestone years 2011 and 2012, and the

contingency provisions. The surplus in NOx emissions for the periods from 2008 ‐ 2011, and

2008 ‐ 2012 are sufficient to offset the shortfall in VOC emissions for those same periods and

thus demonstrate RFP. In addition, the surplus in NOx emissions through 2013 is sufficient to

meet the requirement for contingency. Therefore we recommend approval of the DFW RFP

Plan for the serious ozone nonattainment area under the 1997 ozone standard, the associated

contingency measures for 2013, and the MVEBs adopted by the TCEQ for 2011 and 2012.