Document ID: EPA-R03-OAR-2014-0268-0005
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2014-05-29T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                                  REGION III
	1650 Arch Street
	Philadelphia, Pennsylvania  19103

DATE:	April 10, 2014

SUBJECT:	Technical Support Document for the Update of the Motor Vehicle Emissions Budgets for the Allentown-Bethlehem-Easton 1997 8-Hour Ozone National Ambient Air Quality Standard Maintenance Area 

FROM:	Asrah Khadr, Environmental Engineer, EIT	/s/	
            Office of Air Program Planning 

TO:	File
			
THRU: 	Cristina Fernandez, Associate Director	/s/		 
            Office of Air Program Planning
 

A.  BACKGROUND  

On March 7, 2014, the Pennsylvania Department of Environmental Protection (PADEP) submitted a revision to the Commonwealth of Pennsylvania's (Pennsylvania) State Implementation Plan (SIP).  The SIP revision consists of updated Motor Vehicle Emissions Budgets (MVEBs) for nitrogen oxides (NOx) for the 1997 8-Hour Ozone National Ambient Air Quality Standard (NAAQS).  The SIP revision also includes an updated point source inventory for NOx.  The updated budgets were calculated using the Environmental Protection Agency's (EPA) Motor Vehicle Emission Simulator model (MOVES2010a).  The intention of the revised SIP is to replace the approved MOBILE6.2-based MVEBs with budgets based on MOVES2010a and to ensure that the SIP revision still provides for attainment of the 1997 8-Hour Ozone NAAQS.   

On July 18, 1997 (62 FR 38856), EPA established the 1997 8-Hour Ozone NAAQS.  On April 30, 2004 (69 FR 23858), Lehigh, Northampton and Carbon Counties were designated as nonattainment for the 1997 8-Hour Ozone NAAQS as the Allentown-Bethlehem-Easton 1997 8-Hour Ozone NAAQS Nonattainment Area.  On June 26, 2007, PADEP submitted a SIP revision which consists of a maintenance plan, a 2002 base year inventory and MVEBs for transportation conformity purposes.  On March 2, 2008 (73 FR 11557), EPA approved the SIP revision as well as the redesignation request made by PADEP.  The Allentown-Bethlehem-Easton 1997 8-Hour Ozone NAAQS Nonattainment Area was redesignated as the Allentown-Bethlehem-Easton 1997 8-Hour Ozone NAAQS Maintenance Area (Allentown Maintenance Area).  

The MVEBs are a mobile source inventory to which an area's transportation improvement program (TIP) and long range transportation plan must conform.  Conformity to MVEBs in a SIP means that transportation activities will not produce new air quality violations, worsen existing violations, or delay timely attainment of the NAAQS or any required interim milestones.  This March 7, 2014 SIP revision submittal provides updated MVEBs for NOx.  The budgets were developed utilizing MOVES2010a.  On March 2, 2010 (75 FR 9411), EPA published a notice of availability for the MOVES2010 model for use in SIP submissions and started a two year grace period for the use of MOVES2010 for transportation conformity purposes.  The two year grace period was scheduled to end on March 2, 2012.  On February 27, 2012 (77 FR 11394), EPA published a final rule extending the grace period another year to March 2, 2013 to ensure adequate time for affected parties to adopt the model.  On September 8, 2010, EPA released MOVES2010a, which is a minor update to MOVES2010.  Pennsylvania utilized MOVES2010a in its November 19, 2012 SIP revision.  MOVES2010a was used in order to ensure that the nonattainment area can demonstrate transportation conformity using MOVES2010a once the 3-year conformity grace period expires.  Pennsylvania updated their SIP-approved MVEBs with the use of MOVES2010a.  The budgets were previously developed with the use of the Highway Mobile Source Emission Factor Model (MOBILE6.2).   

MOBILE6.2 is a motor vehicle emissions factor model that was utilized for SIPs and transportation conformity.  MOBILE6.2 was made available for use in SIPs and transportation conformity purposes on May 19, 2004 (69 FR 28830).  MOBILE6.2 was merely an update to MOBILE6 that added the ability for the program to estimate direct exhaust and brake and tire wear particulate matter emission factors as well as exhaust emission factors for particulate matter precursors. 

MOVES2010 improves upon MOBILE6.2 in many aspects.  MOVES2010 utilizes a plethora of vehicle data that has been made available since the release of MOBILE6.2; this vehicle data includes emissions data for different kinds of vehicles.  The new data has allowed EPA to better understand on-road mobile source emissions and their contribution to emissions inventories as well as how effective different control strategies are.  The MOVES2010 model offers more flexibility because the program has a database design that allows easier organization of input and output files and data.  The database design of the MOVES2010 model allows much easier update of input data upon the release of new data.  MOVES2010 also accounts for temperature and speed variations and allows the model to run at a higher resolution which allows for the input of more activity data. 

Under section 176(c) of the Clean Air Act (CAA), any federal action is required to conform to the applicable SIP.  A part of this requirement for conformity is transportation conformity.  Transportation conformity requires that any federally funded transportation plan, program or project conform to the applicable SIP for the transportation-related criteria pollutants (ozone, carbon monoxide, fine particulate matter (PM2.5), coarse particulate matter (PM10), and nitrogen dioxide).  The transportation conformity rules can be found at 40 CFR 93, Subpart A.  One of the requirements found under 40 CFR 93, Subpart A is that any transportation plan, TIP or project not in a conforming TIP must conform to the MVEBs in the applicable SIP.  In order for the MVEBs in a SIP to be used to determine conformity of a transportation plan, TIP or project, the MVEBs must be either approved or deemed adequate.  In this case, the budgets must be approved because this SIP revision is revising already approved budgets.  However, in reviewing such a submitted SIP it remains useful to apply the criteria used to make an adequacy finding.  The requirements for adequacy are set forth in 40 CFR 93.118(e)(4)(i)-(vi).  The criteria for adequacy and how they are met by the Pennsylvania submittal are found below in Table 1.  Adequacy Criteria.

Table 1.  Adequacy Criteria
                                   Criterion
                                   Submittal

(i) The submitted control strategy implementation plan revision or maintenance plan was endorsed by the Governor (or his or her designee) and was subject to a State public hearing;
   * Letter addressed to Shawn M. Garvin, Regional Administrator, EPA Region III from E. Christopher Abruzzo, Secretary, Pennsylvania DEP.
   * Public hearing documents were submitted. 

(ii) Before the control strategy implementation plan or maintenance plan was submitted to EPA, consultation among federal, State, and local agencies occurred; full implementation plan documentation was provided to EPA; and EPA's stated concerns, if any, were addressed;
   * N/A, this revision does not accompany a control strategy implementation plan or maintenance plan.

(iii) The motor vehicle emissions budget(s) is clearly identified and precisely quantified;
   * Appendix C-2 of the submittal provides detailed emission summary tables.

(iv) The motor vehicle emissions budget(s), when considered together with all other emissions sources, is consistent with applicable requirements for reasonable further progress, attainment, or maintenance (whichever is relevant to the given implementation plan submission);
   * Maintenance plan was already approved on March 2, 2008 (73 FR 11557), no changes to nonroad and area source emissions, point source emissions were updated.
   * Allentown Maintenance Area continues to attain the 1997 Ozone NAAQS as shown by the preliminary design value obtained from 2011-2013 data.
   * Update of point source emissions shows less emissions than those predicted in the maintenance plan. 

(v) The motor vehicle emissions budget(s) is consistent with and clearly related to the emissions inventory and the control measures in the submitted control strategy implementation plan revision or maintenance plan; and
   * The SIP revision shows no change in any control measures in the previously submitted maintenance plan.

(vi) Revisions to previously submitted control strategy implementation plans or maintenance plans explain and document any changes to previously submitted budgets and control measures; impacts on point and area source emissions; any changes to established safety margins (see § 93.101 for definition); and reasons for the changes (including the basis for any changes related to emission factors or estimates of vehicle miles traveled).
   * Changes in MVEBs are clearly documented and explained in the submittal.  The higher emissions are due to the use of MOVES2010a which is a more accurate emissions model and is based on more recent data on vehicle emissions than MOBILE6.2.  Update of point source emissions and addition of small safety margin are well explained. 

B.  STATE SUBMITTAL

On March 7, 2014, PADEP submitted a SIP revision which included an update to the MVEBs for NOx for the years 2009 (interim year) and 2018 (maintenance year).  The updated MVEBs were produced using the MOVES2010a model. The MVEBs were developed with guidance from the following EPA guidance documents:  Policy Guidance on the Use of MOVES2010 for SIP Development, Transportation Conformity, and Other Purposes and Technical Guidance on the Use of MOVES2010 for Emission Inventory Preparation in State Implementation Plans and Transportation Conformity.  The submittal also included an update to the point source emissions inventory. 

I.  Methodology for Developing Data for Use in MOVES2010a

PADEP utilized MOVES2010a to provide emissions rates for emissions of NOx.  PPSUITE is a program that was utilized for the processing of highway information and to provide input files that are usable by the MOVES2010a model.  PPSUITE was run utilizing CENTRAL; CENTRAL is a program that provides a process for the proper function of PPSUITE and MOVES2010a.  The MVEBs were developed for NOx and volatile organic compounds (VOCs) since they are the two biggest contributors to the formation of ozone.  The MVEBs for VOCs were not updated in this SIP revision. 

In PPSUITE, the Pennsylvania Department of Transportation (PennDOT) Roadway Management System (RMS) data among other data was utilized to produce vehicle miles traveled (VMT) estimates.  The VMT produced via PPSUITE was then imported into the county data manager (CDM) in MOVES2010a.  Since VOCs and NOx emissions differ with respect to travel speed, travel speed is utilized as an input in MOVES2010a. To develop an array of travel speeds, PPSUITE was utilized to develop vehicle hours of travel (VHT) by speed bin file which allows for the distribution of speeds across links into MOVES2010a speed bins.  The travel speed calculations were completed with guidance from Technical Guidance on the Use of MOVES2010 for Emission Inventory Preparation in State Implementation Plans and Transportation Conformity. 

Road type distribution was another traffic input for MOVES2010a.  Road type distribution was developed with the use of PPSUITE.  The five different road types utilized by MOVES2010a are off network, rural restricted access, rural unrestricted access, urban restricted access and urban unrestricted access.  In addition, ramps are not included in road type distribution so it is assumed that 8% of the roadway VHT is ramp VHT.  This traffic input assumption is consistent with EPA's technical guidance.  

Before RMS data is utilized by PPSUITE to develop various traffic inputs, several adjustments must be made.  The RMS VMT is adjusted to meet the Highway Performance Monitoring System (HPMS) VMT totals.  HPMS VMT utilizes snapshots of RMS VMT to satisfy reporting requirements established by the Federal Highway Administration (FHWA).  To make this adjustment, adjustment factors were calculated and utilized. 

Adjustments to average annual daily traffic (AADT) were completed because calculations for ozone precursors are based on a summer weekday, since that is when ozone formation tends to be the greatest.  The RMS AADT volumes are adjusted by the use of a seasonal factor that was developed by PennDOT's Bureau of Planning and Research (BPR) to produce July traffic volumes.  The RMS data was also adjusted for differences in hourly traffic volumes.  The 24-hour pattern data provided to PPSUITE allowed PPSUITE to provide roadway segment volumes by the hour.  The 24-hour pattern data was obtained from PennDOT's PBR. 

Traffic volume forecasts had to be applied to estimate future emissions from vehicles.  The growth rates utilized for these forecasts are the PennDOT PBR growth rate forecasting system, the regional travel model and any applicable Marcellus Shale related activity growth.  Additionally, county specific growth rates were utilized from a 2005 PennDOT report titled Statistical Evaluation of Projected Traffic Growth, Traffic Growth Forecasting System: Final Report, March 14, 2005.  

MOVES2010a utilizes 13 vehicle source types.  Since HPMS utilizes different categories for vehicle types, the RMS traffic volumes were disaggregated to the 13 vehicle source types which were then combined into the 6 HPMS vehicle classes.  Vehicle type data input into PPSUITE is used to divide the roadway segment volumes with respect to the MOVES2010a source types.  The source types are split into percentages among the 24-hours of the day.  The vehicle source type percentages are then utilized to adjust vehicle speeds in response to trucks. 

Vehicle population is also another important input for MOVES2010a.  Vehicle population is input into MOVES2010a with respect to the 13 vehicle source types utilized by the model. County level vehicle registration data is utilized for light duty vehicles and school buses. Transit bus data is obtained from PennDOT's National Transit Database (NTD); it is utilized to estimate county level transit bus counts.  Heavy duty vehicle population data is estimated by utilizing source type VMT and vehicle source and pattern data are utilized.  Vehicle age is input into the model as well.  The vehicle age is input into the model as a percentage of vehicles of the fleet between ages 0 and 31.  

Outside of vehicle and roadway data, environmental variables are utilized as inputs since evaporative emissions are dependent on the surrounding temperatures.  The environmental variables used included hourly temperatures and humidity values. The temperatures were retrieved by Weather Bank, Inc.  Humidity values were produced according to EPA's technical guidance.  Minimum and maximum monthly temperatures were converted to hourly temperatures using EPA converters in the MOVES2010a model. 

Fuel parameters were also input since different fuels produce different emissions.  The MOVES2010a default fuel formulation and supply data was utilized and updated with local volumetric fuel property data.  Gasohol market penetration and RVP values were updated at the county level.  

Refueling emissions were not included as an input because Pennsylvania provides the refueling emissions in its area source inventory; hence it is not required for the production of MVEBs.  Additionally, MOVES2010a also includes input parameters for inspection and maintenance (I/M) programs.  The inputs for the I/M program include: program start year, stringency level, first and last model years subject to the program, waiver rates, compliance rates, program type and effectiveness, frequency of inspection, vehicle type coverage and test type.  The defaults for an I/M program in MOVES2010a were modified to accurately represent the I/M program for each county. 

II.  Running MOVES2010a

As stated in Section I, the data utilized to run MOVES2010a is a mixture of local and national data.  Local data is utilized for all inputs that have significant impact on the emissions rates that are calculated by MOVES2010a.  The local data utilized as inputs for MOVES2010a is categorized into five categories which include: traffic data, vehicle descriptions, fuel parameters, I/M programs, and environmental variables.  The inputs for traffic data include vehicle type VMT, vehicle population, VMT fractions, road type distribution, and ramp fractions.  The inputs for vehicle descriptions include vehicle type mix, vehicle age distribution, average speeds and hourly distributions of different vehicles.  The inputs for fuel parameters include RVP, sulfur level and ethanol volume.  The inputs for I/M programs include start and model years, the frequency of tests, test standards, source types, stringency of tests, the waiver rate, and compliance rates.  The inputs for environmental variables include hourly temperatures and humidity.  

MOVES2010a inputs that were prepared by PPSUITE included vehicle type VMT, vehicle population, VMT fractions, average speed distributions, road type distribution and ramp fractions.  These files were input into the MOVES2010a county data importer.  Additional non-PPSUITE inputs included fuel and vehicle ages, as well as temperatures and I/M programs.  The county data importer was run in batch mode.  Running the county data importer converts input files into a MYSQL format which is accepted by MOVES2010a.  Afterwards, a MOVES run specification file (.mrs) was created.  This file includes options and different data locations for the execution of the model.  MOVES2010a can be executed to provide an emissions rate or an emissions inventory.  In this submittal, MOVES2010a was executed to provide an emissions inventory.  The emissions estimates of NOx produced for the years 2004, 2009 and 2018 by MOVES2010a are provided in Table 2.  Summary of Motor Vehicle Emissions in tpd.  The emissions estimates are provided in tons per day (tpd); also provided in Table 2 is the comparison between the emissions produced by MOBILE6.2 and MOVES2010a.  No new emissions estimates were produced for VOCs therefore their inclusion into the MOVES estimates portion in the table below is not applicable (N/A).  After reviewing this submittal, EPA concurs with Pennsylvania that even though the emissions results produced by MOVES2010a are greater than those previously calculated using MOBILE6.2.  EPA's review of the SIP revision indicates these higher emissions result from improvements in the MOVES model rather than from unanticipated growth or changes in control measures.  The MOVES results are more accurate estimates of the emissions that actually occurred in 2004 and 2009, rather than an indication that emissions are increasing.  More importantly, the Allentown Maintenance Area attained the 1997 8-Hour Ozone NAAQS and was redesignated to a maintenance area on March 2, 2008 (73 FR 11557).  The Allentown Maintenance Area continues to attain the 1997 8-Hour Ozone NAAQS as shown by its 2011-2013 preliminary design values.  The preliminary 2011-2013 design value for the Allentown Maintenance Area is 74 parts per billion (ppb).  Therefore, EPA finds this update to the MVEBs does not interfere with the Allentown Maintenance Area's ability to maintain its attainment of the1997 8-Hour Ozone NAAQS.

Table 2.  Summary of Motor Vehicle Emissions in tpd
Model
                                   MOBILE6.2
                                  MOVES2010a
Year
                                                                           2004
                                                                           2009
                                                                           2018
                                                                           2004
                                                                           2009
                                                                           2018
VOCs 
                                                                          30.54
                                                                          22.80
                                                                          13.28
                                                                            N/A
                                                                            N/A
                                                                            N/A
NOx 
                                                                          48.33
                                                                          33.89
                                                                          14.44
                                                                          59.38
                                                                          44.08
                                                                          21.95

III.  Review of MOVES Modeling 

To run the MOVES2010a model, a run specification (hereafter referred to as "RunSpec") must be created so the appropriate parameters are selected for the modeling run.  The RunSpecs were reviewed against the following EPA document:  Technical Guidance on the use of MOVES2010 for Emission Inventory Preparation in State Implementation Plans and Transportation Conformity.  This guidance document provides guidance on the use of the MOVES model to develop inventories for SIPs as well as analysis of emissions for transportation conformity determinations.  MVEBs were submitted for the years 2009 and 2018 for the 1997 Ozone NAAQS which are consistent with the rest of the emissions inventory in the maintenance plan.  The submitted RunSpecs, input files and output files were reviewed and found to have followed the applicable EPA guidance provided in the Technical Guidance on the use of MOVES2010 for Emission Inventory Preparation in State Implementation Plans and Transportation Conformity.  Table 3.  RunSpec Reviews for the 1997 8-Hour Ozone NAAQS for Years 2009 and 2018 for Lehigh, Northampton, and Carbon Counties, presents the RunSpec parameters that were reviewed and each parameter's respective component in the submittal.

Table 3.  RunSpec Reviews for the 1997 Ozone NAAQS for Years 2009 and 2018 for Lehigh, Northampton, and Carbon Counties
Domain/Scale
County scale was selected.  Selection of county scale is acceptable for this air quality analysis. 
Calculation Type
Inventory was selected which is acceptable for this analysis.
Time Aggregation Level
Hourly time aggregation was selected.  Selection of hourly time aggregation level is acceptable for this analysis.
Calendar Year Of Evaluation
The appropriate calendar year was selected for each RunSpec; each RunSpec has 2009 or 2018 as the selected calendar year.  MOVES2010b can model years 1990 and 1999-2050.  
Month of Evaluation 
July was selected to be the month of evaluation.  This is acceptable for ozone precursor analysis. 
Type of Day of Evaluation
Weekdays were selected, which is appropriate for the evaluation of pollutant emissions related to ozone.  
Hours of Evaluation 
Starting and ending hours create a whole day (from 0-24 hours).
Geographic Bounds 
The appropriate county was selected for each RunSpec.  The three counties modeled were Lehigh, Northampton, and Carbon Counties.  
Vehicles/Equipment: On-Road Vehicle Equipment 
Appropriate combinations of fuels and source use types were made.
Road Type 
Selection included all necessary road types. 
Pollutants and Processes 
NOx, total gaseous hydrocarbons, non-methane hydrocarbons, and VOCs were selected.     
On-Road Retrofits 
N/A
ROP
N/A
Output Database/Unit Selection
Mass units selected to be grams; energy units selected to be million British Thermal Unit (BTU); distance units selected to be miles. 
Output Emission Detail in Emission Rate Calculations
Emission detail was selected via user preference.  The output emissions detail does not affect the results of the modeling runs, therefore user preference is acceptable. 
Advanced Performance Features 
N/A

IV.  Safety Margins and Allotment of MVEBs for each MPO

Since there is a significant difference between the projected emissions for the maintenance year and the attainment year a small portion of that difference was made into a safety margin.  In other terms, the emissions for the attainment year are much greater than the emissions for the interim (2009) and maintenance (2018) years, which allows for a portion of those excess emissions to become a safety margin.  A two tpd safety margin was added for NOx emissions for the 2009 and 2018 MVEBs.  The MVEBs are presented below in Table 4.  Revised MVEBs in tpd.  The differences between the 2004 attainment year and the 2009 interim year and 2018 maintenance year for NOx are found below in Table 5.  NOx Emissions and Differences for Years 2004, 2009, and 2018 in tpd.  Table 5 presents decreases in emissions which are significant in some categories between the attainment, interim and maintenance years.  Because the 2009 and 2018 emissions are less than the 2004 attainment year emissions, a small portion of the excess emissions can be allocated to safety margins while the area can continue to attain the 1997 8-Hour Ozone NAAQS.  

Additionally, there are two metropolitan planning organizations (MPOs) that serve the three counties that are a part of the Allentown Maintenance Area. The Lehigh Valley MPO serves Lehigh and Northampton Counties while the Northeastern Pennsylvania Alliance (NEPA) MPO serves Carbon County.  To simply the transportation conformity process for these MPOs, separate budgets will be given to each MPO.  Table 6. MVEBs for Each MPO presents how the MVEBs will be allotted to each MPO. 

Table 4.  Revised MVEBs in tpd
Year
                                                                           2009
                                                                           2018
VOCs 
                                      N/A
                                                                            N/A
NOx 
                                                                          46.08
                                                                           14.9

Table 5.  NOx Emissions and Differences for Years 2004, 2009, and 2018 in tpd
Category
                                                                           2004
                                                                           2009
 2004-2009
                                                                           2018
    2004-2018
Point 
                                                                           58.8
                                                                           27.0
                                                                           31.8
                                                                           26.1
                                                                           32.7
Area 
                                                                            2.9
                                                                            3.1
                                                                           -0.2
                                                                            3.2
                                                                           -0.3
Nonroad 
                                                                           12.9
                                                                           11.0
                                                                           1.90
                                                                            6.6
                                                                           6.30
Mobile 
                                                                           59.4
                                                                           44.1
                                                                           15.3
                                     22.0
                                                                           37.4
Total 
                                                                          134.0
                                                                           85.2
                                                                           48.8
                                                                           59.9
                                                                           74.1

Table 6.  MVEBs for Each MPO
MPO
                               Lehigh Valley MPO
                                   NEPA MPO
Year 
                                                                           2009
                                                                           2018
                                                                           2009
                                                                           2018
VOCs
                                                                        20.6482
                                                                        12.4328
                                                                         3.4372
                                                                          2.263
 NOx
                                                                        39.1787
                                                                        20.4058
                                                                         6.8977
                                                                          3.541

C.  EPA EVALUATION AND CONCLUSION

EPA thoroughly evaluated the submittal made by Pennsylvania through PADEP.  EPA's detailed review has led us to conclude that the development methodology of the MVEBs is consistent with applicable guidance documents intended to guide the development of on-road inventories and MVEBs.  EPA also reviewed the MVEBs using the adequacy criteria set forth in 40 CFR 93.118(e)(4)(i)-(vi), and as documented above we found that the budgets meet all of the adequacy criteria.  Based on the results of EPA's in depth review of the SIP revision, the area's continued attainment of the 1997 8-Hour Ozone  NAAQS and the results of EPA's review of the MVEBs using the adequacy criteria in the transportation conformity rule, EPA is proposing to approve the SIP revision.