MEMORANDUM 

SUBJECT: Technical Support Document for Attainment Redesignation for Missouri Portion of the 

St. Louis MO-IL Area; 1997 8-Hour Ozone Standard and Associated Maintenance Plan 

FROM: Lachala Kemp/l}\ 

Air Planning ~d Development Branch 

TO: EPA-R07-0AR-2014-0900 

THRU: Joshua Tapp, 

Branch Chief, AWMD/APDB 

Michael Jay, 

Section Chief, A WMD/ APDB/ AtPS 

I. Introduction 

The purpose of this document is to provide a technical summary of the EPA Region 7 review of 

the emissions inventories submitted with the Redesignation Request and Maintenance Plan for the 

Missouri portion of the St. Louis 1997 Ozone Nonattainment Area by the Missouri Department of 

Natural Resources (MDNR). 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. 

MDNR submitted the Redesignation Demonstration and Maintenance Plan for the Missouri 

Portion ofthe St. Louis Nonattainment Area for the 1997 Ozone NAAQS to EPA on November 3, 2011. 

In April of2014, MDNR revised their submittal plan document to include supplemental information to 

address several issues. The following is a list to describe the changes to the original plan submitted in 

November 2011. 

• The future year emissions projections in the maintenance plan has been changed from 2022 to 

2025 . All referenceslto emissions in 2022 throughout the plan and appendic' have been revised 

to refer to emissions in the new future year (2025). 

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The new future year in the plan (2025) also relies on CAIR to control these emissions. 

The plan and appendices have been updated to accurately characterize all of these 

revisions; 

The on-road mobile source inventories included for the base year (2008) and interim year 

(2017) of the plan have been revised to incorporate the current inspection/maintenance 

(liM) program in place in the St. Louis area. For VOC emissions, the Stage II refueling 

emissions have been removed from the mobile source inventory and added to the area 

source inventory. For the interim year (2017) emissions inventory, the Stage II control 

program was removed from the mobile model in calculating the Stage II area source 

emissions to account for a current SIP development to remove these requirements as a 

result of wide spread use of on-board vapor recovery equipment. The new future year 

(2025) emissions inventory in the plan also accounts for the removal of Stage II controls 

and incorporates the appropriate I/M input in the mobile model. The plan and appendices 

have been updated to accurately characterize all of these revisions; 

The non-road source emissions inventories for the base year (2008) and interim year 

(2017) will be revised to account for errors that were discovered in the inputs to the 

NONROAD model used to develop the inventories. Additionally, it was discovered that 

aircraft takeoff and landing emissions were not properly accounted for in the original 

plan for the base year (2008) and interim year (2017), and revisions have been made to 

correctly add these emissions to these inventories included in the plan. In this plan, nonroad source NOx emissions are lower than the 2011 plan because the Air Program used 

the newer version of the 2008 National Emissions Inventory (NEI version 3) in this plan. 

Commercial marine NOx emissions decreased when compared to the 2011 plan because 

they were found to be overestimated in the 2008 NEI version 2. The new future year 

(2025) non-road emissions inventory included in this document was calculated using the 

appropriate modeling inputs and properly accounts for air craft takeoffs and landings. 

The plan and appendices have been updated to accurately characterize all of these 

revtswns. 

MDNR submitted additional clarifying information that updated the point source 

emission inventory projections for 2017 and 2025 using Cross-State Air Pollution Rule 

(CSAPR) for the control measure strategy on April of2014. 

• On May 21, 2012, EPA revoked the 1997 8-hour ozone standard for the purposes of 

Transportation Conformity [77 FR 30160]. 6 ofthe Plan was revised accordingly. 

• Minor changes to references and narrative language revisions have been made throughout the 

plan and appendices to add clarity, fix typographical errors, and to ensure the plan and 

appendices are reflective of the revisions that have been made. 

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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 "base year" inventory. The base year inventory contains ozone precursor pollutants such as NOx (nitrogen oxides) 

and VOC (volatile organic compounds) emissions. This section will discuss the 2002 Nonattainment 

Year Inventory that was used in the St. Louis Redesignation Request and Maintenance Plan submitted 

byMDNR. 

The St. Louis portion ofthe bi-state nonattainment area consists of Franklin, Jefferson, St. 

Charles, St. Louis County and St. Louis City. The 2002 base year inventory from these counties include emissions from point, area, on-road mobile and non-road emissions. On May 31, 2007, EPA approved 

Missouri's 2002 Base Year Inventory for the Missouri Portion of the St. Louis Ozone Nonattainment 

area (72 FR 30272). Summary tables of the 2002 anthropogenic emissions inventory for the St. Louis 

ozone nonattainment area may be found in Appendix A of the Missouri submittal SIP submittal called, 

"Redesignation Demonstration and Maintenance Plan for the Missouri Portion of the St. Louis 

Nonattainment Area for the 1997 8-Hour Ground Level Ozone National Ambient Air Quality Standard". 

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 for comparison to show the area will remain in attainment. The St. Louis area 2008 

base year inventory contains ground-level ozone precursor (NOx and VOC) emissions. This section will 

discuss the 2008 Attainment Year Inventory that was used in the St. Louis Redesignation Request and 

Maintenance Plan submitted by MDNR. 

The 2008 attainment year inventory includes point, area, on-road mobile, and off-road mobile 

source categories for NOx and VOC. MDNR utilized two mobile inventories for the 2008 year because it 

was required to update the old mobile model, Mobile 6, to the newer mobile model called, Motor Vehicle Emissions Simulator (MOVES). The first 2008 inventory is for the attainment year which was 

developed using Mobile 6.2 for the mobile sources and the second 2008 inventory is for the maintenance 

base year which was developed using MOVES and it is used to compare with future year inventories 

(2017, 2025). Details of the 2008 base/attainment year annual emissions inventory for the Missouri side 

of the nonattainment area is included in Appendix E of the Missouri Submittal and in Appendix B for 

ozone season emissions. Illinois has an approved maintenance plan for their portion of the 

nonattainment area under the 1997 ozone NAAQS, which was approved by EPA on June 12,2012 

(77 FR 34819). 

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Non point 

For the 2008 Nonpoint emissions, ozone season day emissions were calculated from Emissions 

Modeling Clearinghouse (EMCH) temporal allocation profiles that are Standard Classification Codes 

(SCC)-specific. Ozone season day emissions are typical of a Tuesday in July. Detailed information can 

be found in the Missouri submittal in Appendix B-7 for the temporal allocation method tables, Appendix 

B-7 outlines this procedure for area sources. Non-road ozone season day emissions may be found in the 

Missouri submittal in Appendix B-6. 

Nonroad 

For 2008 Nonroad mobile sources, the MDNR generated the emissions using EPA's NONROAD 

model. Since commercial marine vessels and locomotive emissions are not part of the NONROAD 

model, they were calculated outside of the model and transferred to the Nonroad section of the inventory 

from the NEI. 

Onroad 

The 2008 Onroad Mobile source inventory was developed using EPA's highway mobile source 

emissions model MOVES for the maintenance plan base year. However, the 2002 nonattainment base 

year was developed before the requirement to update the model from mobile-6 to MOVES and thus, was 

developed utilizing Mobile-6. In order to keep the comparison on equal terms, MDNR created two 

different mobile modeling inventories for 2008 utilizing both models, Mobile-6.2 and MOVES with all other source categories remaining the same. For the 2008 attainment year inventory, it was developed 

using Mobile 6.2 to compare with the 2002 nonattainment base year. The second 2008 mobile inventory 

was developed utilizing MOVES to establish a maintenance base year for comparison to the future 2017 

and 2025 MOVES based future year inventories. This was done for a smooth transition to the updated 

model and to prevent comparing a MOVES version of2008 attainment year with the Mobile-6 version 

of the 2002 nonattainment base year inventory. EPA Region 7 staff reviewed the files and the emission 

results provided by MDNR and found them to be acceptable. Additional details about the development 

of the MOVES-based 2008 on-road mobile emissions inventories are located in Appendix B of the 

Missouri SIP submittal called, "Redesignation Demonstration and Maintenance Plan for the Missouri 

Portion of the St. Louis Nonattainment Area for the 1997 8-Hour Ground Level Ozone National 

Ambient Air Quality Standard". 

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and 2025 emission projections for the interim and maintenance plan end year, respectively. The 

projected point, area and mobile source emissions on the Missouri side of the nonattainment area for 

2025 were estimated using the 2008 base year inventory. Point source and nonpoint sources were 

developed using growth factors to project the future year inventory. EPA's Nonroad Model and EPA's 

onroad mobile model, MOVES were utilized to project mobile source future inventories. For EGU 

facilities, emissions for the future year were projected based on permanent and enforceable controls for 

each source. 

Point Source 

The projected point source emissions on the Missouri side of the nonattainment area for 2025 

were estimated using the 2008 base year inventory and a growth factor was applied. Growth factors 

were created from the EGAS model (http://www.epa.gov/ttnecasl/egas5.htm) using economic growth 

projections from the Policy Insight® Model for Regional Economic Model, Inc. (REMI). 

For the following EGU facilities, Ameren's Labadie, Meramec, Rush Island, and Sioux, the 

actual regulatory ozone season (May- September) NOx emissions from these Ameren units from 2008-

2011 were obtained from the Clean Air Market Division database and averaged to obtain a yearly 

regulatory ozone season average ofNOx emissions over these four years. This yearly regulatory ozone 

season average ofNOx emissions over these four years were then divided by 153 (the number of days in 

the regulatory ozone season to obtain the projected average ozone season day emissions in 2025 for 

these four facilities. This four year average of regulatory ozone season NOx emissions was determined 

to be representative of the projected NOx emissions from these facilities in 2025 because of CAIR. In 

2015, their allowances from CAIR drop significantly, but they will likely have some banked allowances 

allowing them to hold their ozone season NOx emissions steady for the first several years after the 2015 

CAIR allocations take effect. More information can be found in Appendix D of Missouri's submittal 

called, "Redesignation Demonstration and Maintenance Plan for the Missouri Portion of the St. Louis 

Nonattainment Area for the 1997 8-Hour Ozone National Ambient Air Quality Standard". 

Nonpoint/Area 

The area source emissions in the Missouri portion of the St. Louis nonattainment area for 2025 

were estimated using the 2008 base year inventory and growth factors appropriate for each source 

category. Growth factors were created from the EGAS model (http://www.epa.gov/ttnecasllegas5.htm) 

using economic growth projections from the Policy Insight® Model for Regional Economic Model, Inc 

(REMI). 

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NONROAD model. MDNR

s nonroad mobile source emissions inventory also includes emissions from 

aircraft takeoffs and landings, commercial marine vessels, and locomotives which are not included in the 

NONROAD model. For these three categories, emissions were grown from the year 2008 to the future 

year 2025 using EGAS growth factors for both sides of the nonattainment area. Additional details 

regarding the development of the 2008 and 2025 non-road source emissions inventory for the Missouri 

side of the nonattainment can be found in Appendix B for 2008 and in Appendix D for 2025 of the 

Missouri Plan. 

Onroad 

Onroad mobile projection emissions for 2017 and 2025 were calculated from MOVES produced 

modeling as performed by MDNR. MDNR ran the MOVES model in an "inventory mode" to calculate 

emissions totals for each county in the nonattainment area and used VMT data from East-West Gateway 

Council of Government in coordination with the St. Louis Transportation Conformity Interagency 

Consultation Group. 

For VOC emissions, refueling emissions have been removed from the mobile source inventory 

and added to the area source inventory. For the interim year (2017) and the future year (2025) emissions 

inventory, the Stage II control program was removed from the mobile model in calculating the Stage II 

area source emissions to account for a current SIP revision to remove these requirements as a result of 

wide spread use of on-board vapor recovery equipment. 

Additional details about the development of the MOVES-based 2008 and 2025 onroad mobile 

emissions inventories for the Missouri side of the nonattainment area are located in Appendix B for 

2008 and Appendix D for 2025 in the Missouri submittal. 

IV. Conclusion 

EPA Region 7 staff reviewed the methodologies for preparing these emissions inventories 

provided by MDNR and, for the reasons stated above, found them to be acceptable and approvable 

under section 172 (c) (3) of the Clean Air Act. 

Technical Support Document (TSD) for the Redesignation Request and Maintenance Plan for the StLouis, 

Missoup 1997 Ozone Nonattainment Area I 

Submitted March 2014 by the Missouri Department ofNatural Resources 

TSD Prepared by Steven Brown, U.S. Environmental Protection Agency, Region 7, October 28, 2014 

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