Washington_DQPM25_TSD.doc

Hi Marilyn,

Sorry I hadn’t sent this earlier- time just slipped by. Here is the write up for the DC Area 2002 base year

inventory. Let me know if you have any questions. Talk to you soon.

Janet

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Janet C. Kremer

Environmental EngineerU.S. EPA- Region 3

215-814-2147
emissions. 1The base year 

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

PM2.5 NAAQS, the pollutants to be inventoried are primary emissions (including

condensable) ofPMlO and PM2.5, and emissions of S02, NH3, VOC, and NOx. For the

PM 2.5 NAAQS emissions should be reported as actual annual weekday emissions. The

State Air Agencies defined their base year inventory was for 2002. For the Washington

DC-MD-VA (the Washington Area) SIP, the geographic coverage includes sources in theDistrict of Columbia (VA); Arlington, Fairfax, Loudoun, and Prince William Counties

and the cities of Alexandria, Falls Church, Fairfax, Manassas, and Manassas Park in

Virginia (VA); as well as Charles, Frederick, Montgomery, and Prince George counties

and the cities ofBowie, College Park, Gaithersburg, Greenbelt, Frederick, Rockville, and

Takoma Park in Maryland (MD). A significant amount of documentation is required for

these SIP base year estimates which have been provided by the State Air Agencies.

The State Air Agencies, along with the Metropolitan Washington Council of

Governments (MWCOG), worked together to develop a 2002 base year inventory for the

Washington Area. The State Air Agencies, in collaboration with MWCOG, developed

the point source data for 2002 base year inventory. The State Air Agencies provided its

2002 actual annual emissions for NOx, CO and VOC at the facility level and at the

process-level. It should be noted that the State of Maryland also included Andrews AirForce Base as a point source- called a quasi-point source (a compilation of emissions

from several different source types, totaled under a single point source).

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 calculated onan annual basis. VOC and NOx emissions for Virginia and the District of Columbia were

prepared by their respective state air agencies, PM2.5, PM1O, SO2, and NH3 emissionswere prepared by the Visibility Improvement State and Tribal Association ofthe

Southeast (VISTAS) and the Mid-Atlantic/Northeast Visibility Union (MANE-VU).

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.

“Emissions Inventory Guidance for Implementation ofOzone and Particulate Matter National Ambient

Air Quality Standards (NAAQS) and Regional Haze Regulations” EPA-454/R-05-OO1, August 2005
activity data, from the operations within their respective counties, to determine emissions.

VA used emission factors from a 1997 EPA Technical Memorandum. The WashingtonArea 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 aviation airports (located in MD and VA), and three airports that

serve military airport traffic (located in MD and VA). The State Air Agencies usedseveral sources ofinformation to obtain emission rates and activity data: Federal

Aviation Administration’s (FAA) Air Traffic 1990. and the Airport Activity Statistics of

Certified Route Air Carriers; landing and takeoff cycle information from the Aviation

Administration and the Federal Aviation Administration Airport License Renewal

Applications; and FAA’s Emissions & Dispersion Modeling System (EDMS). All

Nonroad mobile source emissions were provided by SCC.

The Onroad Mobile Source 2002 emissions inventory was developed using the

most current version of EPA’s highway mobile source emissions model MOBILE 6.2 and

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/year were provided by SCC.

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

2002 PM 2.5 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 whereapplicable, provided a justification of a higher percentage than EPA’s previous policy

(which assumed 80% rule effectiveness for applicable sources unless otherwisespecified). Rule penetration is an estimate of percentage 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.