Technical Support Document (TSD) for 

Emissions Inventories for the Maintenance Plan Update 

for the Fredericksburg Area 1997 8-Hour Ozone NAAQS 

Maintenance Area: NOx Motor Vehicle Emission 

Budget Revisions Based on MOVES 2010a

Submitted by the Commonwealth of Virginia

Department of Environmental Quality

TSD Prepared June 2012 by

Jessica L. Fry

Office of Air Monitoring and Analysis, 3AP40

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

/s/

____________________________________________

Reviewed by Walter Wilkie, Associate Director

Office of Air Monitoring and Analysis (3AP40)

June 15, 2012

Date Signed

 
I. Introduction

The purpose of this document is to provide a technical summary of the Office of Air 

Monitoring and Analysis (OAMA) review of the emissions inventories submitted with 

the Maintenance Plan Update for The City of Fredericksburg, Spotsylvania County, and 

Stafford County 1997 8-Hour Ozone NAAQS Maintenance Area: NOx Motor Vehicle 

Emission Budget Revisions Based on MOVES2010a (Fredericksburg area SIP revision)

by the Commonwealth of Virginia Department of Environmental Quality (VADEQ). 

This review does not determine the approvability of the Fredericksburg area SIP revision. 

Virginia is updating their NOx motor vehicle emissions budgets submitted in the 1997 8-

hour ozone NAAQS for the Fredericksburg area for 2009 and 2015 using MOVES2010a 

and subsequently reviewing and updating (if needed) the NOx emissions inventories for 

point, nonpoint, nonroad, and onroad sources. Emission inventories in this

Fredericksburg area SIP revision are used to document that the SIP continues to meet 

applicable requirements when previous onroad mobile emissions inventories are replaced 

with MOVES2010a inventories. The plan should also demonstrate that growth and 

control strategy assumptions for point, nonpoint, and nonroad mobile sources continue to 

be valid and any minor updates do not change the overall conclusions of the SIP. Any 

questions pertaining to this technical summary should be directed to Walter Wilkie, 

Associate Director, Office of Air Monitoring and Analysis, at 215-814-2150 or via email 

at wilkie.walter@epa.gov. 

II 2009 and 2015 Emissions Inventories 

In this Fredericksburg area SIP revision, emissions inventories are used to support 

the States claim that the area is continuing to attain the 1997 8-hour ozone standard as set 

forth in the SIP when using MOVES 2010a for the onroad mobile emissions inventory. 

In order to do this, the state should review the point, nonpoint, and nonroad NOx

emissions inventories submitted with the SIP for the interim year and out year and 

determine if changes in growth and control strategy assumptions affect the conclusion 

that the area will remain in compliance with the 1997 8-hour ozone standard.

In the Fredericksburg Area SIP revision VADEQ analyzed the NOx point source 

emissions estimates for 2009 and 2015 submitted with the 1997 ozone NAAQS

Fredericksburg area SIP. Virginia concluded the estimates submitted for 2009 in the 

maintenance plan had been overestimated and due to their conservative nature the point 

source emissions were not recalculated for this revision. OAMA staff reviewed the 

analysis and believes it is reasonable.

Virginia conducted an analysis of the NOx emissions estimates for nonpoint 

sources submitted for 2009 and 2015 with the 1997 ozone NAAQS Fredericksburg SIP to 

determine if the nonpoint NOx emissions inventories need to be updated for this revision. 

In order to account for changes in nonpoint sector planning VADEQ compared 

socioeconomic data submitted in the SIP to more recent information gathered from the 
George Washington Region Commission’s 2035 Constrained Long-Range Transportation 

Plan. VADEQ also compared the emissions estimates to the draft Mid-Atlantic Regional 

Air Management Association (MARAMA) 2007 inventory1 which was developed using 

more recent methodologies for inventory development. VADEQ concluded the nonpoint 

source emissions did not need to be recalculated for this SIP revision. OAMA staff 

reviewed the analysis and believes it is reasonable.

The nonroad emissions inventory estimates for NOx submitted for 2009 and 2015 

in 1997 ozone NAAQS Fredericksburg area SIP were calculated using USEPA’s draft 

NONROAD2004 model. For this Fredericksburg area SIP revision, VADEQ calculated 

nonroad emissions estimates using EPA’s NONROAD2008a model. Aircraft, 

locomotives, and commercial/military marine vessels were calculated separately. 

Virginia concluded that the general downward trend in NOx emissions in this sector 

supports the conclusion that the area will continue to maintain compliance with the 1997 

8-hour ozone standard. OAMA staff reviewed the analysis and believes it is reasonable.

In the Fredericksburg area SIP revision, VADEQ revised the 2004 and 2009 

onroad NOx emissions inventories and the 2015 projection inventory for the 

Fredericksburg area using the MOVES2010a model. Virginia used the same activity data 

submitted in the SIP where appropriate and replaced any projected inputs with actual 

year-specific data if it was available. For developing inputs to MOVES2010a for 2009 

and 2015, Virginia obtained jurisdictional, road-specific, average daily VMT and speed 

data for 2007 provided by Virginia Department of Transportation (VDOT). The 2007 

data were based on the region’s travel demand model and growth rates were applied to 

estimate VMT for 2009 and 2015. The VMT by vehicle type for each roadway type was 

developed from VDOT’s Traffic Monitoring system and adjustment factors for the month 

of July were provided to account for the variation in VMT that occurs during the ozone 

season. In accordance with the EPA technical guidance2for MOVES an average July 

weekday can be used to represent an ozone season weekday. Vehicle age distribution and 

vehicle population inputs for MOVES2010a were developed using the most current 

registration data provided from the Virginia Department of Motor Vehicles (DMV). 

VADEQ used the same meteorology inputs that were used in the SIP. Virginia provided 

MOVES2010a input and output files in addition to the RunSpec files for review. Mobile 

emissions values were given in units of tons per day by jurisdiction. OAMA staff 

reviewed the files and emission results and believes them to be reasonable.

 

1 EPA consulted with VADEQ and it should be noted that in Table 7: MARAMA 2007, 2013, and 2017 

Area Source NOx Emissions Estimates provided in the TSD the first column labeled as NOx,tpd, should be 

labeled NOx,tpy. 

2 Using MOVES to Prepare Emission Inventories in State Implementation Plans and Transportation 

Conformity: Technical Guidance for MOVES2010, MOVES 2010a and 2010b, April 2012.