Technical Support Document (TSD) for the 

Redesignation Request and Maintenance Plan 

For the New Castle County Portion of the 

Philadelphia-Wilmington, PA-NJ-DE 

2006 PM2.s Nonattainment Area 

Submitted November 2012 by the Delaware 

Department of Natural 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 Alice 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 2006 PM2.5 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 

2007 Base Year Inventory and Nonattainment 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. For the purposes of this plan this inventory is called the base year inventory 

and contains primary PM2.s emissions (including condensibles), S02, NOx, VOC, and NH3. In a 

redesignation request, emissions inventories are used to support the States claim that the area has 

permanent and enforceable emissions reductions. In order to do this, the state should estimate 

the percent reduction (from the year that was used to determine the design value for designation 

and classification) achieved from federal and state control measures; this is usually termed as the 

nonattainment year "base year" inventory. This inventory also contains primary PM2.s emissions 

(including condensibles), S02, NOx, VOC, and NI-h. DNREC did not include VOC and NH3 

emissions in their tables in their report having determined them to be insignificant; however, 

they were submitted in the data package to EPA. DNREC submitted the 2007 inventory to fulfill 

both of these requirements. This section will discuss the 2007 base year/nonattainment year 

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

For the 2007 nonattainment 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 of the 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 MOVES2010. 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 staff reviewed the files and the emission results provided by DNREC and found 

them to be acceptable. 

III. Emissions Inventories for Maintenance Plan 

2008 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 PM2.s emissions (including condensibles), S02 and 

NOx . Emissions for VOC and NH3 have been supplemented with the 2008 v3 NEI. This section 

will discuss the 2008 attainment year inventory that was used in the New Castle County portion 

of the Philadelphia-Wilmington, PA-NJ-DE Redesignation Request and Maintenance Plan 

submitted by DNREC. 

The 2008 point source inventory contained emissions for EGU and Non-EGU sources in 

New Castle County. EPA guidance for emissions inventory development provides that actual 

emissions should be used for purposes of the base year inventory. DNREC DAQ developed their 

point source inventory from information and data collected from facilities in the state. 

For the 2008 Nonpoint emissions, DNREC used the 2005 Delaware Periodic Emission 

Inventory as the starting point for their source category selection and methodology development. 
They added agricultural burning as a new source category to the nonpoint sector. DNREC also 

applied new methods and updated emissions factors to existing source categories where 

available. The majority of Delaware's work involved collecting new activity data from local 

sources and applying it to the inventory. DNREC also did a review of point and nonpoint 

sources to make sure there was no double counting of sources. 

For the 2008 Nonroad emissions, DNREC used the 2005 Delaware Periodic Emission 

Inventory as the starting point for their source category selection and methodology development. 

The latest versions ofthe EPA's NONROAD model and the Federal Aviation Administration's 

(FAA) Emissions and Dispersion Modeling System (EDMS) were used in the development of 

the 2008 inventory. Similar to the development of the Nonpoint inventory the majority of the 

work involved in developing the inventory consisted of collecting new activity data from local 

sources and applying it to the inventory. The Nonroad inventory contains emissions from 

aircrafts, locomotives, commercial marine vehicles (CMV), and other off-road vehicles and 

equipment 

The 2008 Onroad Mobile source inventory was developed using the most current version 

of EPA's highway mobile source emissions model MOVES2010. Delaware used county specific 

inputs for the model where appropriate. 

OAMA staff reviewed the files and the emission results provided by WVDEP and found 

them to be acceptable. 

IV. 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 methodologies developed through the MARAMA 

. regional planning process for the interim and maintenance plan end year, respectively. They did 

this by adjusting the 2007 future year growth factors to a 2008 base year by using the 

methodologies found in the Technical Support Document for the Development of the 

2013/201 712020 Emission Inventories for Regional Air Quality Modeling in the Northeast/MidAtlantic Region (MARAMA 2017 TSD) and the Technical Support Document for the 

Development of the 2025 Emission Inventory for PM2.5 Nonattainment Counties in the MANEVU 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 2008 inventory. The Department of Energy 2011 

______ A_n_nu::-a-.,1,.--E_n_e_rgy Outlook growth factors with control factors lied due to Delaware's EGU 

regulations were used to develop the projected EGU emissions. Details regarding the emissions 

budgets can be found in the Technical Support Document (TSD)-Adequacy Findings for the 

Motor Vehicle Emissions Budgets in the Maintenance Plans for the Delaware Portion ofthe 

Philadelphia-Wilmington PA-NJ-DE 1997 and 2006 Fine Particulate (PM2.5) National Ambient 

Air Quality Standards (NAAQS) Nonattainment Area. 
Nonpoint emissions for 2017 and 2025 were also developed by applying the appropriate 

growth/control factors to the 2008 inventory. 

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

EPA's NMIM/NONROAD 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. 

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

acceptable.