Technical Support Document (TSD) Forthe 2011 Base Year Inventory For the Washington DC-MD-VA 2008 OzoneNAAQS Nonattainment Area

Submitted July 2014 by the District Department ofthe Environment Maryland Department ofthe Environment, and VirginiaDepartment ofEnvironmental Quality

TSD Prepared March 2015 by Jessica L. Fry Office ofAir Monitoring and Analysis, 3AP40 U.S. Environmental Protection Agency, Region 3 1650 Arch Street Philadelphia, Pennsylvania 19103

Reviewed byAlice H. Chow, Associate Director Office ofAir Monitoring and Analysis (3AP40)I. 

### Introduction

The purpose ofthis document is to provide a technical summary ofthe Office ofAir Monitoring and Analysis (OAMA) review ofthe 2011 Base Year Inventory submitted for the Washington DC-MD-VANonattainment Area (NAA) 2008 OzoneNAAQS bythe District Department ofthe Environment (DDOE), the Maryland Department ofthe Environment (MDE), and the VirginiaDepartment ofEnvironmental Quality (VADEQ). EPA designated the NAA as marginal for the 2008 Ozone NAAQS effective July 20, 2012. This requires the area to submit a comprehensive base year inventory no laterthan 24 months from the July 20, 2012 effective date and everythree years thereafter. A SIP Base Year Inventory is the startingpoint from which other SIP inventories are derived as well as serving as the benchmark for other SIP planning activities, such as the establishment ofan emissions reduction creditprogram. Underthe Clean AirAct (CAA) sections 172(c)(3) and 182(a)(1 ), states are required to submit emissions inventory information for all relevant sources for the areas that are designated nonattainment. The DDOE, MDE, and VADEQ hereinreferred to as "state air agencies," in collaboration with the Metropolitan Washington Council ofGovernments (MWCOG) have submitted the 2011 Base Year Inventory for the Washington DC-MD-VA 2008 OzoneNAAQS Nonattainment Area in order to fulfill the CAA requirements. Any questions pertaining
to this technical summary should be directed to Alice H. Chow, Associate Director, Office ofAir Monitoring and Analysis, at 215-814-2144 or via email at chow.alice@epa.gov.



### II 2011 Base YearInventory

Under section 172(c)(3) states are required to submit a comprehensive, accurate, current accounting ofactual emissions from all sources (point, nonpoint, nomoad, and onroad) in the nonattainment area. The CAA section 182(a)(l)requires that areas designated as nonattainment and classified as marginal are to submit an inventory ofall

sources ofozone precursors no later than 2 years after the effective date ofdesignation. This inventory contains actual annual emissions ofprimary PM2

.semissions (including condensibles), S02, NOx, CO,VOC, and NH3. Typical ozone season day emissions for the ozone season ofMay through September were submitted for NOx, CO,and VOC. The base year inventory includes emissions estimates from stationary point and nonpoint
sources, omoad mobile sources, and nomoad mobile sources. Forthe NAA
,the geographic coverage includes sources in the District ofColumbia (DC); Calvert, Charles, Frederick, Montgomery, and Prince George Counties in Maryland (MD); and Arlington, Alexandria, Fairfax, Loudoun, and Prince William Counties in Virginia (VA).

The state air agencies, in collaboration with MWCOG, developed the point source data for the 2011 base year inventory. The point source inventory contains emissions for EGU and Non-EGU sources in the NAA. EPA guidance for emissions inventory development provides that actual emissions should be used for purposes ofthe base year inventory. The state air agencies developed their 2011 inventory byusing emissions directly reported by the facilities. MWCOG compiledthe ozone season day and annual emissions provided the by the state air agencies and included them in the plan. The emissions were provided at the facility level and process-level.Forthe 2011 nonpoint source emissions, also known as "area sources," the state air agenciesprovided an inventory that contains estimations ofemissions by multiplying

an emissionfactor by some known indicator ofcollective 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. The state air agencies defined the summer ozone season as May through September.

The 2011 nonroad mobile source inventory was prepared by MWCOG with EPA'sNONROAD2008 model. NONROAD estimates fuel consumption and emissions for all nonroad mobile source categories except for aircraft, locomotives, and commercial marine vessels. EPA'aNMIM2008 software (versionNMIM20090504), the NMIM County Database (NCD20130531_nei2011vl), and the NONROAD 2008amodel (July 2009 version) were run for the NAA for both an average ozone season day and annual emissions. The period May through September was considered for ozone season analysis, while four season approach was adapted for developing annual emissions. Emission estimates for locomotive engines, aircraft emissions and commercial marine vessels were provided separately. The state air agencies estimated emissions separately for these

sources using local datafor each oftheirrespective counties.

The onroad mobile source 2011 emissions inventory was developed using the EPA'shighway mobile source emissions model MOVES 2010a. The National Capitol Region Transportation Planning Board (TBP) developed transportation related inputs and

ranthe model using fuel and inspection and maintenance program inputs provided by the
state air agencies, and meteorology inputs developed by the Metropolitan WashingtonAir Quality Committee (MWAQC) staff. MW AQC staffreviewed and approved these emissions.

OAMA staffreviewed the results, procedures, and methodologies for the SIP base year, and found them to be acceptable.