Technical Support Document (TSD) for the 

Redesignation Request and Maintenance Plan 

For the New Castle County Portion of the 

Philadelphia-Wilmington, PA-NJ-DE 

1997 PM2.s Nonattainment Area 

Submitted November 2012 by the Delaware 

Department ofNatural Resources and Environmental Control 

TSD Prepared January 2014 by 

Jessica L. Fry 

Office of Air Monitoring and Analysis, 3AP40 

U.S. Environmental Protection Agency, Region 3 

1650 Arch Street 

Philadelphia, Pennsylvania 19103 

Reviewed by Allee H. Chow, Associate Director 

Office of Air Monitoring and Analysis (3AP40) 
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 Redesignation 

Request and Maintenance Plan for the New Castle County portion of the PhiladelphiaWilmington, PA-NJ-DE 1997 PM2.s Nonattainment Area by the Delaware Department ofNatural 

Resources and Environmental Control (DNREC). This review does not determine the 

approvability of the redesignation request or maintenance plan. Emissions inventories in a 

redesignation request are used to show permanent and enforceable emission reductions between 

the year the area was designated as a nonattainment area and the year the area came into 

attainment. In a maintenance plan, the emissions inventories are used to reflect the emissions 

during the time the area came into attainment and are then projected to show that the area will 

remain in attainment. Any questions pertaining to this technical summary should be directed to 

Alice H. Chow, Associate Director, Office of Air Monitoring and Analysis, at 215-814-2144 or 

via email at chow.alice@epa.gov. 

II. Emissions Inventories for Redesignation Request 

2002 Base Year Inventory 

Under section 172(c)(3) states are required to submit a comprehensive, accurate, current 

accounting of actual· emissions from all sources (point, nonpoint, nonroad, and onroad) in the 

nonattainment area. This inventory is called the base year inventory and contains primary PM2.5 

emissions (including condensibles), S02, NOx, VOC, and NH3. DNREC submitted their 2002 

Base Year Inventory to EPA as a State Implementation Plan (SIP) revision on April 3, 2008. The 

inventory was approved by EPA and the rule became effective April 3, 2013 (78 FR 14020). 

III. Emissions Inventories for Maintenance Plan 

2007 Attainment Year Inventory and Maintenance Plan Base Year Inventory 

The inventory used for the year of attainment is called the attainment year inventory and 

also is referred to as the maintenance plan base year inventory. This inventory is used as the 

basis for the projected inventories that are used to show the area will remain in attainment. The 

base year inventory contains primary PMz.s emissions (including condensibles), S02 and NOx. 

DNREC submitted VOC and NH3 emissions in their data package submitted to EPA, although it 

is not represented in the tables in the report. This section will discuss the 2007 attainment year 

inventory that was used in the New Castle County portion of the Philadelphia-Wilmington, PANJ-UE Kedesignation Request and Maintenance Plan submitted by DNREC. 

For the 2007 attainment year inventory for all source categories (point, nonpoint, 

nonroad, and onroad) DNREC submitted the 2007 Version 3 Emissions Inventory developed 

through the Mid-Atlantic Regional Air Management Association (MARAMA) regional planning 

process. A comprehensive county level inventory for the Philadelphia nonattainment area 
(NAA) was developed by the DNREC's Department of Air Quality (DAQ), in coordination with 

MARAMA, New Jersey and Pennsylvania's Department of Environmental Protection. 

Documentation of the development ofthe inventory can be found in Technical Support 

Document for the Development of the 2007 Emission Inventory for the Regional Air Quality 

Modeling in the Northeast I Mid-Atlantic Region Version 3.3. January 23, 2012. 

The 2007 point source inventory contained emissions for electric generating units 

(EGUs) and Non-EGU sources in New Castle County, DE. EPA guidance for emissions 

inventory development provides that actual emissions should be used for purposes of the base 

year inventory. The point source inventory submitted was developed by MARAMA in 

consultation with DNREC DAQ using information compiled from 2007 Annual Emissions 

Reports submitted to Delaware from Point sources in the state. 

The nonpoint source emissions inventory for 2007 was developed using 2007 specific 

activity data along with EPA emission factors and the most recently available emission 

calculation methodologies. 

The 2007 nonroad emissions were generated the emissions using EPA's National Mobile 

Inventory Model (NMIM) emissions model. Marine, air and rail/locomotive (MAR) emissions 

are not part of the NMIM and were calculated separately. 

The 2007 onroad mobile source inventory was developed using EPA's highway mobile 

source emissions model MOVES2010a. The analysis was performed by the Northeast States for 

Coordinated Air Use Management (NESCAUM) for MARAMA's regional planning process. 

Vehicle miles traveled (VMT) data for 2007 was provided by the Delaware Department of 

Transportation (DelDOT). 

OAMA staffreviewed the files and the emission results provided by WVDEP and found 

them to be acceptable. 

III. Projection Emissions Inventories for Maintenance Plan 

2017 and 2025 Projection Emission Inventories 

Projection inventories are used to show that the area will remain in attainment. DNREC 

used 2017 and 2025 emission projections developed through the MARAMA regional planning 

process for the interim and maintenance plan end year, respectively. Emission projections, 

emission methodologies and growth factors for 2017 and 2025 can be found in the Technical 

Support Document for the Development of the 2013/201712020 Emission Inventories for 

Regional Air Quality Modeling in the Northeast/Mid-Atlantic Region (MARAMA 2017 TSD) 

and the Technical Support Document for the Development of the 2025 Emission Inventory for 

PM2.5 Nonattainment Counties in the MANE-VU Region, January 2012 (MARAMA 2025 TSD), 

respectively. 

The 2017 and 2025 point source inventories were estimated by using appropriate 

growth/control factors and applying them to the 2007 inventory. The Department of Energy 2011 
Annual Energy Outlook growth factors, with control factors applied due to Delaware's EGU 

regulations were used to develop the projected EGU emissions. 

Nonpoint emissions for 2017 and 2025 were also developed by applying the appropriate 

growth/control factors to the 2007 inventory. 

Nonroad source emissions for 2017 and 2025 were developed using growth factors from 

EPA's NMIM model. 

DNREC developed an onroad mobile emissions inventory for 2017 and 2025 using 

MOVES 2010. However, for mobile budget purposes DNREC is using the 2012 inventory in 

lieu of the projected mobile emissions for 2017 and 2025. The 2012 onroad inventory modeling 

was performed by WRA Associates LLP, Wilmington, Delaware, under contract to DelDOT 

using the MOVES 2010 model. Details regarding the emissions budgets can be found in the 

Technical Support Document (FSD)-Adequacy Findings for the Motor Vehicle Emissions 

Budgets in the Maintenance Plans for the Delaware Portion of the Philadelphia-Wilmington PANJ-DE 1997 and 2006 Fine Particulate (PM2.5) National Ambient Air Quality Standards 

(NAAQS) Nonattainment Area. 

OAMA staff reviewed the methodologies provided by DNREC and found them to be 

acceptable.