Document ID: EPA-R03-OAR-2013-0058-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2013-08-08T04:00Z

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

DATE:	

SUBJECT:	Technical Support Document for the Motor Vehicle Emissions Budgets for the Lancaster 1997 8-Hour Ozone 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 November 19, 2012, the Pennsylvania Department of Environmental Protection (DEP) 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) and volatile organic compounds (VOCs) for the 1997 8-Hour Ozone National Ambient Air Quality Standard (NAAQS).  The SIP revision also includes an updated point source inventory for NOx and VOCs.  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 23860), Lancaster County was designated as nonattainment for the 1997 8-Hour Ozone NAAQS.  On September 20, 2006, Pennsylvania DEP submitted a SIP revision which consisted of a maintenance plan, a 2002 base year inventory and MVEBs for transportation conformity purposes.  On November 8, 2006, Pennsylvania DEP supplemented their September 20, 2006 submittal.  On July 6, 2007 (72 FR 36889), EPA approved the SIP revision as well as the redesignation request made by Pennsylvania DEP and Lancaster County was redesignated as a 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 January 31, 2013 SIP revision submittal provides updated MVEBs for NOx and VOCs.  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. 
        Table 1.  Adequacy Criteria for the Lancaster Maintenance Area
                                   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 Michael L. Krancer, 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 for  Lancaster County was already approved on July 6, 2007 (72 FR 36889), no changes to area and nonroad source emissions, point source emissions were updated.
   * Lancaster County continues to attain the 1997 8-Hr Ozone NAAQS as shown by the design value obtained from 2009-2011 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 November 19, 2012, Pennsylvania DEP submitted a SIP revision which included an update to the MVEBs for NOx and VOCs 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 includes an updated point source emissions inventory. 

I.  Methodology for Developing Data for Use in MOVES2010a

Pennsylvania DEP utilized MOVES2010a to provide emissions rates for emissions of NOx and VOCs.  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 VOCs since they are the two biggest contributors to the formation of ozone. 

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.  Other fuel parameters were obtained through the MOVES2010a default data.

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 Lancaster 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 VOCs and NOx produced for the years 2004, 2009 and 2018 by MOVES2010a are provided in Table 2.  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.  The revised MVEBs produced with MOVES2010a are found below in Table 3.  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 2002 and 2009, rather than an indication that emissions are increasing.  More importantly, Lancaster county attained the 1997 8-Hour Ozone NAAQS and was redesignated to a maintenance area on July 6, 2007 (72 FR 36889).  Lancaster County continues to attain the 1997 8-Hour Ozone NAAQS as shown by its 2009-2011 design values.  The two air quality monitors in Lancaster County are providing design values of 76 parts per million (ppm) and 77 ppm, which are below the 1997 8-Hour Ozone NAAQS of 0.08 ppm.  Therefore, EPA finds this update to the MVEBs does not interfere with Lancaster County's ability to maintain its attainment of the1997 8-Hour Ozone NAAQS.

Table 2.  Summary of Motor Vehicle Emissions for the Lancaster Maintenance Area
Model
                                   MOBILE6.2
                                  MOVES2010a
Year
                                                                           2004
                                                                           2009
                                                                           2018
                                                                           2004
                                                                           2009
                                                                           2018
VOCs (tpd)
                                                                          19.75
                                                                          14.33
                                                                           7.77
                                                                          16.41
                                                                          14.29
                                                                           8.14
NOx (tpd)
                                                                          32.33
                                                                          22.32
                                                                           8.99
                                                                          42.10
                                                                          33.18
                                                                          18.57

          Table 3.  Revised MVEBs for the Lancaster Maintenance Area
Year
                                                                           2009
                                                                           2018
VOCs (tpd)
                                                                          35.18
                                                                          14.29
NOx (tpd)
                                                                          20.57
                                                                          10.14

III.  Revision of Point Source Emissions

In addition to revising the MVEBs for the Lancaster County Maintenance Area, Pennsylvania DEP submitted revisions to its inventory of point source emissions.  The change accounts for a decrease in point source emissions.  The point source emissions were projected for the 2009 interim year in the 2006 maintenance plan SIP submittal and the actual emissions were less than the projected emissions at the time.  Company-reported point source emissions were utilized to update the 2009 interim year inventory.  The previously estimated and the actual interim year inventories are provided in Table 4. The update to the 2018 maintenance year was produced by linear extrapolation between the point source emissions for 2007 and 2020.  These point source emissions were produced by the Mid-Atlantic Regional Air Management Association, Inc. (MARAMA).  The emissions data for the years 2007 and 2020 were obtained from the MARAMA document titled MARAMA 2007, 2017, and 2020 Baseline and Projected Inventories, Version 3.  The emissions provided by this MARAMA document utilize the most recent growth assumptions, which are more recent than the growth assumptions utilized by Pennsylvania DEP in the Lancaster County Maintenance Plan that was submitted in 2006.  The main reason the point source emissions were updated, is because some growth factors decreased while others increased, but overall there is a decrease in projected emissions from the previous 2018 inventory and the 2018 inventory in this submittal.  The previously submitted 2018 point source emissions inventory currently in the maintenance plan and the updated 2018 point source emissions inventory are provided below in Table 5.  The update to the point source emissions has been reviewed and found to be reasonable, an additional technical support document in this docket addresses the revision of the point source emissions. The document is titled Technical Support Document for Emissions Inventories for the State Implementation Plan Revision: NOx and VOC Motor Vehicle Emission Budget Revision 
Based on MOVES2010a. 
   Table 4.  2009 Point Source Emissions for the Lancaster Maintenance Area
 
Estimated
Actual
VOCs (tpd)
                                                                            8.7
                                                                            5.5
NOx (tpd)
                                                                            4.1
                                                                            3.2

   Table 5.  2018 Point Source Emissions for the Lancaster Maintenance Area
 
Maintenance Plan
Updated 
VOCs (tpd)
                                                                             11
                                                                            7.7
NOx (tpd)
                                                                            4.6
                                                                            3.6

IV.  Safety Margins

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. A 2 tpd safety margin was added for VOCs and NOx emissions for the 2018 MVEBs and a 2 tpd safety margin was added for NOx for the 2009 MVEBs.  The differences between the 2004 attainment year and the 2009 interim year and 2018 maintenance year for NOx are found below in Table 6.  The differences between the 2004 attainment year and the 2009 interim year and 2018 maintenance year for VOCs are found below in Table 7. Tables 6 and 7 show that there are decreases 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, the excess emissions can be allocated to the MVEBs while the area can continue to attain the 1997 8-Hour Ozone NAAQS. 

Table 6.  NOx Emissions and Differences for Years 2004, 2009 and 2018 for the Lancaster Maintenance Area
Category
                                                                           2004
                                                                           2009
 2004-2009
                                                                           2018
    2004-2018
Point (tpd)
                                                                           3.89
                                                                            3.2
                                                                           0.79
                                                                            3.6
                                                                           0.29
Area (tpd)
                                                                            2.6
                                                                            2.8
                                                                           -0.2
                                                                            2.9
                                                                           -0.3
Nonroad (tpd)
                                                                           13.2
                                                                           10.8
                                                                            2.4
                                                                            6.8
                                                                            6.4
Mobile (tpd)
                                                                           42.1
                                                                          33.18
                                                                           8.92
                                                                          18.57
                                                                          23.53
Total (tpd)
                                                                          61.79
                                                                          49.98
                                                                          11.91
                                                                          31.87
                                                                          29.92

   Table 7.  VOCs Emissions and Differences for Years 2004, 2009 & 2018
Category
                                                                           2004
                                                                           2009
2004-2009
                                                                           2018
    2004-2018
Point (tpd)
                                                                            8.1
                                                                            5.5
                                                                            2.6
                                                                           7.74
                                                                           0.36
Area (tpd)
                                                                           24.4
                                                                           24.2
                                                                            0.2
                                                                           27.2
                                                                           -2.8
Nonroad (tpd)
                                                                           17.3
                                                                             15
                                                                            2.3
                                                                           11.9
                                                                            5.4
Mobile (tpd)
                                                                          16.41
                                                                          14.29
                                                                           2.12
                                                                           8.14
                                                                           8.27
Total (tpd)
                                                                          66.21
                                                                          58.99
                                                                           7.22
                                                                          54.98
                                                                          11.23

C.  EPA EVALUATION AND CONCLUSION:

EPA thoroughly evaluated the submittal made by Pennsylvania through Pennsylvania DEP.  Our 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.  We 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 our in depth review of the SIP revision, the area's continued attainment of the 1997 8-Hour Ozone  NAAQS and the results of our review of the MVEBs using the adequacy criteria in the transportation conformity rule, EPA is proposing to approve the SIP revision.