Technical Support Document (TSD) For

Emissions Inventories for the Washington DC-MD-VA

8 Hour Ozone State Implementation Plan (SIP) Base Year Inventory.

Submitted June 2007 by the

District of Columbia Department of Health

Maryland Department ofthe Environment,

and

Virginia Department ofEnvironmental Quality

TSD Prepared December, 2008

Janet C. Kremer

Air Quality Analysis Branch, 3AP22

U.S. Environmental Protection Agency, Region 3

1650 Arch Street

Philadelphia, Pennsylvania 19103

Reviewed by Walter Wilkie, Chief

Air Quality Analysis Branch (3AP22)

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Date Signed
the Washington DC-Ml)-VA Nonattainment Area 8 Hour Ozone State Implementation

Plan (SIP) by the District of Columbia Department of Health, the Maryland Department

ofthe Environment (MDE), and the Virginia Department ofEnvironmental Quality. This

review determines the approvability of the SIP Base Year Inventory and an evaluation of

the methods used for projection year inventories. A SIP Base Year Inventory is the

starting point from which other SIP inventories are derived as well as serving as the

benchmark for other SIP planning activities, such as the establishment of an emissions

reduction credit program. Projection year inventories are essentially used to trackprogress; the purpose ofwhich is to demonstrate a reduction in emissions ofregulated

sources from the Base Year to a projected year. The Washington DC-MD-VA

Nonattainment Area was designated as an 8 hour ozone nonattainment area with a

Subpart 2 classification. Subpart 2 area(s) are required to submit initial SIP base year

inventories to EPA by June 15, 2006; with the final Base Year inventory due with the SIP

to EPA by June 15, 2007. The District of Columbia Department of Health, the Maryland

Department ofthe Environment, and the Virginia Department of Environmental Qualityherein referred to as “State Air Agencies,” have submitted Washington DC-MD-VA

Nonattainment Area 8 Hour Ozone SIPs and have requested EPA’s approval oftheir

respective base year emission inventories.

Any questions pertaining to this technical summary should be directed to Walter

K. Wilkie, Chief, Air Quality Analysis Branch, at 215-814-2150 or via email atwi1kie.walter(epa.ov.

II 2002 SIP Base Year Inventory

The SIP base year inventory is the primary inventory from which other

inventories (3-year cycle inventories, reasonable further progress inventories, modeling

inventories) are derived. The Clean Air Act calls for State, local, and Tribal agencies toensure that the base year inventory is comprehensive, accurate, and current for all actual

emissions. 1The base year inventory includes emissions estimates from stationary point

and nonpoint sources, onroad mobile sources, and nonroad mobile sources. For the 8-

hour ozone NAAQS, the pollutants to be inventoried are VOC, NOx and CO (carbonmonoxide). For the 8-hour ozone NAAQS, VOC, NOx and CO emissions should be

reported as actual annual and actual summer weekday emissions (defined as an averageday’s emissions for a typical summer day during the ozone season). The State Air

Agencies base year inventory for the Washington DC-MD-VA (the Washington Area) is

for 2002. For the Washington area, the geographic coverage includes sources in the

District of Columbia (VA); Calvert, Charles, Frederick, Montgomery, and Prince George

l “Emissions Inventory Guidancefor Implementation ofOzone and Particulate Matter National Ambient

Air Quality Standards (NAAQS) and Regional Haze Regulations” EPA-4541R-05-001, August 2005
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2002 actual typical ozone season day emissions and annual emissions for NOx, CO and

VOC at the facility level and at the process-level.

For the 2002 Nonpoint Source emissions, also known as “area sources,” the State

Air Agencies provided an inventory that contained estimations of emissions by

multiplying an emission factor by some known indicator of collective activity for each

source category at the county (or county-equivalent). These emissions are typically

calculated on an annual basis because the activity data are generally only available on an

annual basis. The State Air Agencies converted these annual emissions to seasonal

emissions, for ozone, the summer season is defined as peak ozone season months ofJune,

July, and August. Various sources of emission factors or methodologies were used,

including EPA’s AP-42, EPA’s Emissions Inventory Improvement Program, and EPA

mobile source model. Nonpoint source estimates were provided by SCC.

The Nonroad Mobile Source 2002 inventory was prepared by MCOG with EPA’s

NONROAD2005a model, version as of 02/08/2006, and EPA emission factors.

NONROAD estimates fuel consumption and emissions of total hydrocarbons, carbon

monoxide, nitrogen oxides, sulfur dioxide, and particulate matter for all nonroad mobile

source categories except for aircraft, locomotives, and commercial marine vessels. The

NONROAD2005 model was run the Washington Area for both an average ozone season

day and annual emissions. The period May through September was considered for ozoneseason analysis, while four season approach was adapted for developing annual

emissions. Model inputs were prepared for both ozone season day and the four seasonsfor each jurisdiction. To get average ozone season day emissions, the model was run to

get the period total (June-August 2002) emissions and then these emissions were divided

by 92 (total number of days during the period) to get average ozone season day

emissions. Emission estimates for locomotive engines, aircraft emissions and commercial

marine vessels were provided separately. For locomotive engine and line haul emissions,

DC and MD requested and received fuel usage and activity data, from the operationswithin their respective counties, to determine emissions. VA used emission factors from

a 1997 EPA Technical Memorandum. The Washington Area contains several airports

that have several different types of aircraft with different activity associated with them.

There are two commercial airports (both located in VA), 12 public-use general aviationairports (located in MD and VA), and three airports that serve military airport traffic

(located in MD and VA). The State Air Agencies used several sources ofinformation toobtain emission rates and activity data: Federal Aviation Administration’s (FAA) Air

Traffic 1990, and the Airport Activity Statistics ofCertified Route Air Carriers; landingand takeoff cycle information from the Aviation Administration and the Federal Aviation

Administration Airport License Renewal Applications; and FAA’s Emissions &

Dispersion Modeling System (EDMS). Calvert County, MD is the only county in the

Washington Area that has emissions for commercial marine vessels. MDE used the
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traffic activity data from the National Capitol Region Transportation Planning Board.

MCOG provided Mobile6.2 input and output files for review. Mobile emissions values

were given in units oftons per summer day and were provided by SCC.

The State Agencies also applied rule effectiveness and rule penetration for its

2002 8-hour ozone SIP base year inventories. Rule effectiveness reflects the actual

ability of a regulatory program to achieve the emission reductions required by regulation

(or perhaps voluntarily adopted). The State Agencies applied rule effectiveness and

where applicable, provided a justification of a higher percentage than EPA’s previous

policy (which assumed 80% rule effectiveness for applicable sources unless otherwise

specified). Rule penetration is an estimate ofpercentage of emissions in a source

category that are emitted at facilities subject to the requirements of a rule. The State

Agencies applied rule penetration for its nonpoint sources where applicable.

AQAB staffreviewed the results, procedures, and methodologies for the SIP base

year, and found them to be approvable.

IlL 2008 and 2009 Projection Emission Inventories

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

Projection inventories for the years 2008 and 2009 were used for the Washington DCMD-VA Area SIP. The 2008 projected inventory is required for reasonable further

progress (RFP) and the 2009 projected inventory is required for the attainment year.

Inventories were developed for all emission sources for both years.

The Point Source emissions for 2008 and 2009 were projected, using growth

surrogates from EPA’s Economic Growth and Analysis System, Version 5.0 (EGAS 5.0).

The Nonpoint Source emissions for 2008 and 2009 were projected using growth factors to account for population, household and employment data the Round 7.0

Cooperative Forecasts prepared by MWCOG staff and the VMT projections were

developed by COG Department ofTransportation Planning staff.

For the 2008 and 2009 Nonroad Mobile Source inventories, the State Agencies

used EPA’s NONROAD2005 model to generate these future inventories. The

NONROAD model allows for the calculation of past year, present year, and future year

inventories (up to the year 2050) to be generated. Growth for locomotives and

commercial marine vessels came from employment data as surrogates. Commercial

aircraft growth was provided by Metropolitan Washington Airports Authority, MDE

provided future year emission for military aircraft in their counties, while no growth was

assumed for Virginia military aircraft emissions. MDE also provided emissions for
AQAB staffreviewed the procedures, and found them to be reasonable for

development ofthese inventories.