# MEMORANDUM

  ----------- ----------------------------------------------------------------
  **To:**     Brenda Johnson, EPA Region IV

  **Cc:**     Ron Redus, Quincy Styke, and Barry Stephens, TDEC -- Air
              Pollution Control

  **From:**   Yi Hua Wei, Sharon G. Douglas, and Jay L. Haney, SAI

  **Date:**   20 December 2004

  **Re:**     Responses to EPA Comments on the ATMOS EAC Technical Support
              Document (TSD)

              
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This document provides detailed responses to comments/questions provided
by EPA on 7 October 2004 on the ATMOS EAC TSD (SAI, 2004), which was
submitted to EPA on 31 March 2004. The EPA's comments are numbered in
bold with responses following.

***1. Q: Additional documentation to specifically discuss the local or
state provided information that was used to replace national (i.e., EPA
NEI) or default data should be provided.***

**A**: A detailed accounting of the local and/or state data used to
replace the national emissions information was provided in the TSD. We
repeat these details below and would be pleased to answer any additional
specific questions related to the information used:

**[2001 Current-Year Inventory]{.underline}**

### Point-Source Emissions

The point source emissions were generated based on the following
databases:

[State of Tennessee]{.underline}

-   2001 point source data provided by Davidson County

-   2000/2001 point source data provided by Knox County

-   2001 point source data provided by Hamilton County (NEI99 Version 2
    data with 1999 to 2001 facility closures)

-   2002 point source data provided by Shelby County

-   1999 point source data for rest of 91 counties provided by
    University of Tennessee

-   2001 point source data provided by Eastman Chemical Company located
    in Sullivan County, TN

-   Gas compressor's data provided by the facilities, including actual
    emissions for large gas compressor stations for August/September
    1999 and June 2001; actual 2001 emissions for

-   small compressor stations; and revised stack parameters

    [State of Mississippi]{.underline}

-   2001 point source data provided by MDEQ

    [State of Texas]{.underline}

-   2000 point source data provided by TCEQ

    [Facility-Specific Point Source Data]{.underline}

-   Hourly day-specific data for June 2001 episode provided by Southern
    Company

-   Hourly day-specific data for June 2001 episode provided by TVA

-   Hourly day-specific data for June 2001 episode for three Entergy
    facilities (Independence, White Bluff and R S Nelson) provided by
    Entergy

    [Other States]{.underline}

-   1999 NEI Version 2 point source data for other states.

    **Area and Non-road Emissions**

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-   2001 area source data provided by Davidson County, Tennessee

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-   2000 area and non-road source data for four counties in Little Rock
    area (Faulkner, Lonoke, Pulaski and Saline Counties) provided by
    ADEQ

-   2000 area and non-road source data for State of Texas provided by
    TCEQ

    **Mobile Source Emissions**

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-   The VMT data for the States of Alabama (2000) and Arkansas (2010)
    were prorated to 2001 using the formula provided by the states

-   States of Florida, Georgia, Mississippi, South Carolina, North
    Carolina, Tennessee and Texas: 2001 VMT data

-   State of Louisiana: 2000 VMT data

**[2007 Baseline Inventory]{.underline}**

### Point-Source Emissions

The 2007 point source emissions were developed based on the following
data:

[State of Tennessee]{.underline}

-   Applied future year growth and controls on the county-specific base
    year (1999, 2001 or 2002) emissions data

-   Applied 6% growth rate to the base case level emissions for the gas
    compressors (June 2001 and August/September 1999 emissions as base
    case level for larger gas compressors; and 2002 emissions as base
    case level for smaller gas compressors)

[State of Mississippi]{.underline}

-   Applied future year growth and controls on the base year (2001/2002)
    emissions data, and included the emissions estimates for the
    facilities currently under construction, and will be operating in
    2007

[State of Texas]{.underline}

-   Incorporated point source emissions estimates included the TCEQ 2007
    MCR Phase I Emissions Inventory

[Facility-Specific Data]{.underline}

-   Incorporated the hourly emissions estimates for 2007 provided by
    TVA, and assumed that the CTs only operate 4 hours on three hottest
    days of each episode: June 18-20 for June 2001 episode; July 6-8 for
    July 2002 episode; and September 6-8 for August/September 1999
    episode.

-   Incorporated 2007 emissions estimates provided by Eastman Chemical
    Company

-   Incorporated 2007 emissions estimates for William Refining &
    Marketing LLC provided by Shelby County, TN

-   Incorporated hourly emissions estimates for 2007 for July and
    September episode periods provided by Southern Company for WFOS
    project with day of week matches

-   Kept the emissions for the Entergy facilities (located in States of
    Arkansas, Louisiana and Mississippi) at the base case level

[Other States]{.underline}

Applied future year growth and controls on the final 1999 NEI version 2
data

**Mobile Source Emissions**

The on-road mobile source emissions were prepared using MOBILE6. For the
states of Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi,
South Carolina, North Carolina, Tennessee and Texas, state provided 2007
county-level daily VMT data.

***2. Q: The formulas and rationale provided by the states to prorate
the 2000 VMT data to 2001 should be provided.***

***A:*** The formulas used to prorate the 2000/2010 VMT data to 2001 for
States of Alabama and Arkansas are as follows:

-   State of Alabama:

> 2001VMT = 2000VMT+2000VMT\*0.025 (assuming a 2.5% increment per year).

-   State of Arkansas:

> 2001VMT = 2010VMT\*((growth factor)\^0.1)
>
> (growth factors for each county for 2010 and 2010 VMT were provided by
> Arkansas DEQ).

***3. Q: The documentation should address why the best available data
according to section 176 of the CAA is being used for all supporting
inventory data.***

**A:** Throughout the ATMOS modeling effort, including the recent EAC
phase, we have obtained and used the best information available to
estimate both the base and future-year emission inventories. This
includes the most recent population (2000 Census), county-specific VMT
(base year vehicle counts and future-year estimates), local point source
updates (startups/shutdowns), and the latest available emission
inventory tools (MOBILE6 and NONROAD2004).

***4. Q: Information on how speed data was developed (i.e., sources of
data, how derived) should be supplied.***

**A:**  The speed data provided by the states were used when available.
The States of Georgia and Tennessee conducted in-depth studies to
determine the average speeds for each of 12 roadway types.

 

For other states two different approaches were used:

-   Average speeds for rural and urban roads were used as in the former
    projects and/or based on available nationwide average speed
    distribution data from the Federal Highways Administration. These
    speeds were further discussed with participant states before being
    used, when possible. That was the case for the States of Florida,
    Louisiana, North Carolina and South Carolina and all the states
    using the FHWA VMT data.

 

-   For States of Alabama, Arkansas and Mississippi, given their
    proximity to State of Georgia and other similarities, the average
    speed data was taken from a study conducted on rural and urban roads
    in State of Georgia.

***5. Q: Document and discuss what vehicle registration data (i.e.,
local or default) were used, what year(s) and why?***

**A:** The vehicle registration distribution data was provided by the
States of Georgia, North Carolina, Tennessee and Texas based on studies
conducted in their roadways. For States of Louisiana and South Carolina,
the vehicle registration distribution data was obtained from previous
projects and further discussions with the States. The national default
data was used for other states.

The detailed information on the registration distribution is provided as
follows (No attempt was made to prorate the registration distribution to
future years):

-   State of South Carolina: 1997 registration distribution

-   State of Louisiana: 1999 registration distribution data.

-   State of Georgia: for 2001 the GADEQ provided 1999 registration
    distribution data. For 2007, updated 2002 registration data was
    used.

-   State of North Carolina: registration data was transformed from 2007
    MOBILE 5a input files provided by NCDEQ following instructions
    provided in the MOBILE 6 user's manual. The registration data was
    for year 2001.

-   State of Tennessee: 1999 registration data provided by TNDEQ.

-   State of Texas: for 8 non-attainment counties in Houston area 2000
    registration data was used for the 2001 inventory and 2007
    registration data for 2007 inventory. For all other counties
    national defaults were used.

***6. Q: How were the temperatures used in the MOBILE6 and NONROAD
models developed (i.e., area of representation, county-level, etc) by
episode and year.***

**A:** For the NONROAD model, the monthly maximum, minimum and average
temperatures for each state were used. The temperature data were
calculated based on the 30-year (1970-2000) historical averages (data
obtained from Southern Regional Climate Center web site:
www.srcc.lsu.edu).

For MOBILE6.2 models, the temperatures data were used as follows:

State-provided minimum/maximum temperatures were used when available.
Otherwise 30-year historical minimum and maximum temperature averages
for the month were used (data obtained from the Southern Regional
Climate Center web site: www.srcc.lsu.edu).

For States for which multiple MOBILE6.2 runs were made for specific
areas within the State, the 30-year historical temperatures of the
meteorological sites in the areas or closest to the areas were used. In
some cases, when more than one site was located in that area, an average
of the temperatures reported for those sites were used. In all other
cases, the average temperatures reported by all the meteorological sites
in the state were used. The detailed summary regarding the temperature
data is provided as below:

[States of Arkansas and Mississippi]{.underline}

-   Average temperatures of all available meteorological stations

-   For State of Arkansas: the stations are Fort Smith, Little Rock and
    North Little Rock

-   For States of Mississippi: the stations are Jackson, Meridian and
    Tupelo

 

[State of Alabama]{.underline}

-   For Jefferson and Shelby counties (because of different RVP value):
    used the temperatures at the Birmingham site

-   For all other counties the average of temperatures from all sites
    was used. The stations are Birmingham, Huntsville, Mobile and
    Montgomery

 

[State of Georgia]{.underline}

-   State-provided ozone season temperatures

 

[State of Florida]{.underline}

-   Duval county with inspection and maintenance program: used the
    temperatures at the Jacksonville site

-   Broward, Dade, Hillsborough, Palm Beach and Pinellas counties with
    inspection and maintenance program: used the average temperatures of
    Miami, Tampa and Palm Beach sites

-   All other counties: used the average temperatures of all sites. The
    stations are Apalachicola, Daytona Beach, Fort Myers, Gainesville,
    Jacksonville, Key West, Miami, Orlando, Pensacola, Tallahassee,
    Tampa, Vero Beach and Palm Beach

 

[State of Louisiana]{.underline}

-   For Baton Rouge and East Baton Rouge with inspection and maintenance
    program: used the temperatures at the Baton Rouge site

-   Calcasieu Parish: uses temperatures at the Shreveport site

-   All other counties: used the average temperatures from all sites.
    The stations are Baton Rouge, Lake Charles, New Orleans and
    Shreveport

[State of North Carolina]{.underline}

-   Greensboro with different registration distribution and inspection
    and maintenance program: used the temperatures at the
    Greensboro/Winston-Salem site

-   Mecklenburg with different registration distribution and inspection
    and maintenance program: used the temperatures at the Charlotte site

-   Winston-Salem with different registration distribution and
    inspection and maintenance program: used the temperatures at the
    Greensboro/Winston-Salem site

-   Wake County with different registration distribution and inspection
    and maintenance program: used the temperatures at the Raleigh site.

-   All other counties input file: used the average temperatures of all
    sites. The stations are Asheville, Cape Hatteras, Charlotte,
    Greensboro/Winston-Salem, Raleigh and Wilmington

[State of South Carolina]{.underline}

-   Augusta: uses temperatures at the Greenville site

-   Charleston: uses temperatures at the Charleston AP site

-   Charlotte, NC (because this is an urban site close to SC, the
    MOBILE6 run was used to evaluate impact of emissions on neighboring
    counties in SC): uses temperatures at the Charlotte, NC site 

-   Columbia: uses temperatures at the Columbia site

-   Greenville-Spartanburg: uses temperatures at the Greenville site

-   Savannah, GA (urban area close to SC used to evaluate impact on
    neighboring counties in SC): uses temperatures at the Savannah, GA
    site 

-   Wilmington, NC (urban area close to SC used to evaluate impact on
    counties close to that area in SC): uses temperatures at the
    Wilmington, NC site

 

[State of Tennessee]{.underline}

-   Shelby and Tipton-Fayette counties: uses temperatures at the Memphis
    site

-   Knoxville area: uses temperatures at the Knoxville site

-   Hamilton County: uses temperatures at the Chattanooga site

-   Davidson, Rutherford, Sumner, Williams, Wilson areas: uses
    temperatures at the Nashville site

-   Sullivan area: uses temperatures at the Bristol-Johnson City site

-   East Tennessee counties: used the average temperatures
    of east Tennessee sites. They are Bristol-Johnson City and Knoxville

-   Middle Tennessee counties: uses temperatures at the Nashville site

-   West Tennessee Counties: uses temperatures at the Memphis site

[State of Texas]{.underline}

-   Houston area: used the temperatures at the Houston site

-   All other counties: used the seasonal temperatures for the state

***7. Q: What local information were used to run the MOBILE model versus
national defaults?***

**A:** The following local information was used to run MOBILE6 model:

-   Inspection and maintenance and anti-tampering programs: Local
    information was used for States of Florida, Georgia, Louisiana,
    North Carolina, Tennessee and Texas.

-   State of Georgia provided a specific fuel program, oxygenate fuel
    and reformulated gasoline data in addition to hourly temperature and
    relative humidity values and barometric pressure.

-   State of Texas provided weekday trip length distribution, diesel
    fractions, rebuild effects and a fuel program.

***8. Q: Document why the MOBILE6 model was run for total organic gases
(TOC) instead of VOC.***

***A:*** Since the emissions inventories prepared for the ATMOS modeling
were for the UAM-V with CB-V mechanism, the speciation profiles for CB-V
are generated based on the toxic compounds database which includes FID
HC, methane, ethane and aldehydes. Therefore, the MOBILE6 model was run
for total organic gases (TOG) instead of VOC.

***9. Q: Expand the historical trends data approach used to develop
future mobile emissions and why this is a better method to use than
transportation demand models.***

**A:** Use of historical VMT counts and trends to estimate expected
future VMT is better because VMT counts are available for every county
in Tennessee, whereas Travel Demand Models only cover some counties
associated with major metropolitan areas. For consistency, the
historical VMT trends data were used to estimate future VMT for
Tennessee, but for certain areas (e.g., Nashville), the trends data were
compared with the available TDM estimates.

***10. Q: Explain what is MVCALC?***

**A**: MVCALC is a program which calculates the county-level emissions
for each vehicle class and roadway classification for each pollutant by
multiplying the appropriate emissions factor from MOBILE6.2 by the
county-level VMT for that vehicle class and roadway classification.

***11. Q: How was the Louisiana 2000 VMT data projected to 2001? If used
as is, why.***

***A:*** The Louisiana 2000 VMT data was used for the 2001 inventories;
it was the best available information at the time the modeling
inventories were prepared.

***12. Q: How did the local and state agencies and local sources develop
the point source information that is discussed on page 3-4 and 3-5? Is
there any documentation on this and what if any QA/QC actions were
used?***

**A:** The point source information provided by various state and local
agencies is typically derived from their permitting inventories. The
point source information for Tennessee was prepared by the University of
Tennessee and a report summarizing this inventory is available.

***13. Q: Hourly day specific data provided by Southern Company, TVA,
Entergy were used in the current year inventories? How were the point
source emissions from these companies developed for the base case
modeling inventories for the 1999, 2000 and 2002 episodes if this is not
already addressed in the TSD?***

**A:** Hourly data provided by Southern Company and TVA were derived
from CEM data for each of their units.

***14. Q: Was a 1999 NEI Version 2 point source inventory used for all
other states (page 3-5) in the base case modeling for the 2000, 2001 and
2002 episodes? If not how were those emissions developed?***

**A:** Yes. The 1999 NEI Version 2 point source inventory was used for
all other states.