Mr. Karl Brooks 

Page Two 

Also, due to their size, paper copies ofthe appendices to the plan are not included in this 

package. The disk(s) included with this package include an electronic copy of the plan and 

appendices. 

Thank you for your attention to this matter. If you have any questions regarding this submittal, 

please contact Ms. Wendy Vit with the Missouri Department ofNatural Resources' Air Pollution 

Control Program at P.O. Box 176, Jefferson City, MO 65102 or by telephone at (573) 751-4817. 

Sincerely, 

AIR POLLUTION CONTROL PROGRAM 

Kyr~;:; X7/t~ Director 

KLM:jwc 

Enclosures: 

Copy of plan (paper copies of the appendices are not included) 

Copy of commission signature page certifying Missouri Air Conservation Commission adoption 

Copy of public hearing notices 

Copy of public hearing transcript introductory statement 

Copy ofrecommendation for adoption 

Copy ofthe summary of comments and responses 

CD with electronic copy of the plan and appendices 

c: 	 Missouri Air Conservation Commission 

File# 1997-03-4-STL-Redesignation 

Celebrating 40 years of taking care of Missouri's natural resources. 


To learn more about the Missouri Department of Natural Resources visit dnr.mo.gov. 

Supplement/Revision to the 

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 

Prepared for the 

Missouri Air Conservation Commission 

Adoption: April 24, 2014

Missouri Department of Natural Resources 

Division of Environmental Quality 

Air Pollution Control Program 

Jefferson City, Missouri

Project Number: 1997-O3-4-STL-Redesignation

ii 

TABLE OF CONTENTS 

EXECUTIVE SUMMARY ............................................................................................... 1

FOREWORD: EXPLANATION OF REVISIONS TO THE ORIGINAL 

DOCUMENT ................................................................................................................ 3

1. BACKGROUND/INTRODUCTION ........................................................................... 5

1.1 NATIONAL AMBIENT AIR QUALITY STANDARD FOR OZONE ............................................. 5

1.2 GEOGRAPHICAL DESCRIPTION OF THE ST. LOUIS NONATTAINMENT AREA ....................... 6

1.3 ST. LOUIS OZONE HISTORY ............................................................................................... 8

1.4 CURRENT STATUS / BACKGROUND SUMMARY: 1997 OZONE NAAQS ........................... 11

2. REDESIGNATION AND MAINTENANCE PLAN REQUIREMENTS ............ 13

2.1 ATTAINMENT OF THE STANDARD .................................................................................... 13

2.2 IMPLEMENTATION PLAN APPROVAL ................................................................................ 14

2.3 PERMANENT AND ENFORCEABLE IMPROVEMENT ............................................................ 15

2.4 MAINTENANCE PLAN REQUIREMENTS ............................................................................. 15

2.5 SECTION 110 AND PART D REQUIREMENTS ..................................................................... 18

3. OZONE MONITORING ........................................................................................... 20

3.1 ST. LOUIS OZONE MONITORING NETWORK ..................................................................... 20

3.2 AMBIENT AIR MONITORING DATA .................................................................................. 21

3.3 ST. LOUIS OZONE MONITORING DATA ANALYSIS ........................................................... 26

3.4 MISSING DATA UNDER THE 1997 8-HOUR OZONE STANDARD ........................................ 26

3.5 QUALITY ASSURANCE PROGRAM .................................................................................... 27

3.6 CONTINUED MONITORING COMMITMENT ........................................................................ 27

3.7 CLEAN DATA DETERMINATION ....................................................................................... 27

4. REDESIGNATION REQUEST: EMISSION INVENTORY AND CONTROLS 

FROM 2002 - 2008 ..................................................................................................... 28

4.1 BASE YEAR AND ATTAINMENT YEAR INVENTORIES ....................................................... 28

4.2 PERMANENT AND ENFORCEABLE CONTROLS USED TO ATTAIN THE STANDARD ............. 30

4.3 REASONABLY AVAILABLE CONTROL TECHNOLOGY (RACT) ......................................... 34

5. MAINTENANCE PLAN DEMONSTRATION: EMISSION INVENTORY AND 

CONTROLS FROM 2008 - 2025 .............................................................................. 36

5.1 BASE/ATTAINMENT YEAR INVENTORY AND FUTURE YEAR EMISSION PROJECTIONS ...... 36

5.2 INTERIM YEAR EMISSION INVENTORY: 2017 ................................................................... 41

5.3 FUTURE FEDERAL CONTROL MEASURES ......................................................................... 42

5.4 NEW SOURCE REVIEW: PERMITTING NEW OR MODIFIED EMISSIONS SOURCES .............. 42

5.5 UPDATE: RECENT EMISSION REDUCTIONS 2012 - ........................................................... 43

6. TRANSPORTATION CONFORMITY ................................................................. 46

7. CONTINGENCY MEASURES ............................................................................... 48

8. CONCLUSION ........................................................................................................... 52
iii 

LIST OF TABLES

Table 3-1 2007-2010 St. Louis 8-Hour Design Values

Table 4-1 2002 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Table 4-2 2008 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Table 4-3 Comparison of 2002 and 2008 VOC and NOx Emissions for the Missouri Side of 

the 1997 St. Louis 8-Hour Ozone Nonattainment Area (tons per ozone season 

day) 

Table 5-1 2008 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Table 5-2 2025 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Table 5-3 Comparison of 2008 and 2025 VOC and NOx Emissions for the Missouri Side of 

the 1997 St. Louis 8-Hour Ozone Nonattainment Area (tons per ozone season 

day) 

Table 5-4 2017 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Table 7-1 Contingency Plan for the Missouri Portion of the 1997 St. Louis 8-Hour Ozone 

Maintenance Area 

Table 7-2 Potential Contingency Measures for the Missouri Portion of the 1997 St. Louis 

8-Hour Ozone Maintenance Area 

 
iv 

List of Figures 

Figure 1-1 1997 8-Hour Ozone Nonattainment Area for St. Louis (MO-IL) region 

Figure 3-1 St. Louis Ozone Monitoring Network 

Figure 3-2 2001 – 2010 8-Hour Ozone Design Value Trends – MO 

Figure 3-3 2001 – 2010 8-Hour Ozone Design Value Trends – IL 

Figure 3-4 2001 – 2003 & 2008 – 2010 Design Value Comparison 
v 

List of Appendices 

Appendix A 2002 O3 Season Day Emissions Inventory Summary (MO Counties Only) 

Appendix B 2008 O3 Season Day Emissions Inventory Summary (MO Counties Only) 

Appendix C 2017 O3 Season Day Emissions Inventory Summary (MO Counties Only) 

Appendix D 2025 O3 Season Day Emissions Inventory Summary (MO Counties Only) 

Appendix E 2008 Base Year Annual Emissions Inventory (MO counties only) 

 Appendix E-1 List of Statewide Point Source Emissions by Facility 

 Appendix E-2 Non-road Inventory Documentation 

 Appendix E-3 Nonpoint ICI Combustion Methodology 

 Appendix E-4 MOVES IM Input Development Protocol 

Appendix F Retired Unit Exemption Forms for Trigen and Anheuser Busch 

Appendix G MEMC Consent Agreement Termination
1 

Executive Summary 

The purpose of this SIP revision is to provide the documentation necessary for Missouri's request 

for redesignation of the Missouri portion of the St. Louis nonattainment area to attainment for the 

1997 ozone National Ambient Air Quality Standard (NAAQS). The plan addresses all of the 

federal Clean Air Act Amendments of 1990 (CAA) Section 107(d)(3)(E) redesignation elements 

for the area. One of those elements is a maintenance plan which demonstrates how the area will 

continue to comply with this NAAQS pursuant to CAA Section 175A. The maintenance plan, 

contained within this revision, includes, among other things, an emissions inventory, future year 

emissions projections and contingency measures. 

A corresponding plan, submitted by the Illinois Environmental Protection Agency, has already 

been approved by the U.S. Environmental Protection Agency (EPA) for the Illinois or MetroEast portion of the St. Louis nonattainment area. As a result, the Metro-East portion has already 

been designated attainment for the 1997 ozone standard. 

Ozone air quality has dramatically improved in the St. Louis region as a result of implementation 

of State and Federal control measures since the designation of the St. Louis area as 

nonattainment in 2004. On June 9, 2011, EPA issued a “Clean Data Determination” that the 

entire St. Louis nonattainment area achieved at least three consecutive ozone seasons (2008-

2010) of complete, quality assured ambient air quality monitoring data demonstrating attainment 

with the 0.080 parts per million (ppm) 8-hour ozone NAAQS promulgated in 1997 [76 FR 

33647]. The air quality monitoring data for the most recent years of 2011-2013 also shows 

compliance with the 1997 NAAQS. These air quality improvements are due to permanent and 

enforceable emission control measures. 

This maintenance plan provides for continued attainment of the 1997 8-hour ozone air quality 

standard for the St. Louis nonattainment area for a period of ten years after the EPA has formally 

redesignated the area to attainment. The plan also provides assurances that, in the event of a 

subsequent violation of the air quality standard, additional control options listed in this plan, 

called contingency measures, can quickly be implemented to prevent any future violations. In 

addition, this plan demonstrates that the area attained the standard based on permanent and 

enforceable emissions reductions. This plan also includes an emissions inventory analysis of the 

ozone precursors - Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) – for both 

the redesignation demonstration period (2002- 2008) and the maintenance plan period (2008 – 

2025). 

The State’s efforts to improve ozone air quality in the St. Louis area by no means end with the 

area’s redesignation to attainment under the 1997 8-hour ozone NAAQS. Revisions to the ozone 

NAAQS are ongoing and continuous. On March 27, 2008, the EPA released a revised 8-hour 

ozone standard [73 FR 16436]. This revision lowers the ozone standard to 0.075 ppm (or 75 

ppb). Similarly, a potentially even more stringent revision to the ozone standard is expected in 

2015. For the 2008 ozone NAAQS revision, the St. Louis area was designated nonattainment 

area and classified as marginal [77 FR 30088]. Marginal nonattainment areas have until 

December 31, 2015 to attain the 2008 Ozone NAAQS [40 CFR 51.1103]. The Missouri 

Department of Natural Resources’ Air Pollution Control Program (Air Program) is currently 
2 

developing a plan to address the area’s marginal nonattainment obligations under the 2008 ozone 

NAAQS. 

By redesignating the Missouri portion St. Louis area to attainment under the 1997 standard through 

this plan, the Air Program is establishing contingency measures and anti-backsliding levels. Since 

the implementation rule for the 2008 NAAQS proposes to revoke the 1997 NAAQS, the approval 

of this plan will conclude any obligations under the 1997 standard prior to its proposed revocation. 

This will allow the state to focus its resources on addressing the newly-revised and more protective 

standard(s). 
3 

Foreword: Explanation of Revisions to the Original Document 

On November 27, 2011, the Missouri Air Conservation Commission (MACC) adopted the 

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. The 

plan was then submitted to the EPA on November 28, 2011 for inclusion in the Missouri State 

Implementation Plan (SIP). The plan was not approved at that time due to litigation surrounding 

the federal interstate air pollution transport rules: Clean Air Interstate Rule (CAIR) & its 

successor, Cross State Air Pollution Rule (CSAPR). 

The District of Columbia Circuit Court ruled to vacate CSAPR and directed EPA to continue 

implementing CAIR while awaiting an acceptable replacement rule. Since CAIR remains in 

effect until the Supreme Court makes a decision or a satisfactory replacement rule is enacted, the 

emission reductions from CAIR are permanent and enforceable. 

As a result, this document is an update to the maintenance plan submitted in 2011 (2011 plan). 

The Missouri Department of Natural Resources’ Air Pollution Control Program (Air Program) is 

now proposing a technical supplement/revision to the 2011 plan. This revision will make the 

following updates and corrections to the 2011 plan: 

 The future year in the maintenance plan has been changed from 2022 to 2025. All 

references to emissions in 2022 throughout the plan and appendices have been revised to 

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

 Emissions inventories and appendices have been updated to account for recent changes: 

o Appendix H was created to supply the Emission Inventories for the Illinois 

portion of the nonattainment area; 

o The point source emissions inventories for the interim year (2017) have been 

adjusted so that the Clean Air Interstate Rule (CAIR) is the control strategy used 

to control electric generating units’ emissions as opposed to the Cross State Air 

Pollution Rule (CSAPR). 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; 

o 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 actual 

inspection/maintenance (I/M) 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 
4 

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

appendices have been updated to accurately characterize all of these revisions;

o 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, non-road 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 take offs 

and landings. The plan and appendices have been updated to accurately 

characterize all of these revisions.

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

Transportation Conformity [77 FR 30160]. Chapter 6 has been revised accordingly. 

 For the purposes of increased clarity, e.g. the plan was updated to better show which 

CAA redesignation request & maintenance plan requirements are addressed by which 

sections of the document. 

 Minor changes and corrections have been made throughout the plan and appendices to fix 

typographical errors, revise references, and to ensure the plan and appendices are 

reflective of the updates that have been made. 

Although this document is an update to the 2011 plan, it is stand-alone and therefore 

substantially restates the contents of the 2011 plan except for the changes mentioned above. The 

original 2011 plan submittal may be found at http://www.dnr.mo.gov/env/apcp/docs/stl-ozonemaintplan-redesig.pdf . 
5 

1. Background/Introduction 

1.1 National Ambient Air Quality Standard for Ozone 

Congress first enacted the Clean Air Act (CAA) in 1970. It was last amended in 1990. The 

CAA requires the U.S. Environmental Protection Agency (EPA) to set National Ambient Air 

Quality Standards (NAAQS) for pollutants considered harmful to public health and the 

environment. There are two categories of NAAQS that are set by the EPA. The primary 

standards are health-based standards and are designed to establish limits to protect public health. 

The secondary standards are commonly referred to as “welfare-based standards” and are meant 

established to protect public welfare. These limits are intended to protect against decreased 

visibility, and damage to crops, animals, and buildings. Currently there are six pollutants with 

established primary level NAAQS. These pollutants are carbon monoxide, lead, total suspended 

particles, sulfur dioxide, nitrogen oxide, and ozone. These pollutants are referred to as “criteria” 

pollutants. The EPA establishes a standard for each criteria pollutant. If an area is found to 

exceed this value, it is classified as a nonattainment area for that specific pollutant. The states 

and/or tribes responsible for the affected area must then develop and carry out strategies and 

measures to attain the NAAQS. The goal for any areas designated as “nonattainment” is to be 

reclassified by the EPA to attainment for the pollutant. 

The CAA requires that the EPA carry out a periodic review of the NAAQS. This review must 

include the scientific basis for (1) changing or reaffirming the NAAQS and (2) implementing the 

NAAQS. As required by the CAA, the EPA reviewed the one-hour NAAQS for ozone in the 

1990’s and determined that a new standard was needed. This new standard was finalized in July 

of 1997. The replacement of the ozone NAAQS was pursuant to subpart 1 of the CAA, Title I, 

Part D. 

The 1997 ozone standard is based on an eight-hour averaging period. This standard defines an 

area as in attainment of the 8-hour ozone standard when the three-year average of the annual 

fourth highest daily maximum 8-hour ozone concentration is less than or equal to 0.08 parts per 

million (ppm) (or 80 parts per billion (ppb)). Due to rounding conventions in the 1997 standard, 

an 8-hour average ozone concentration above 0.085 ppm is considered an exceedance of 

standard. When the three-year average value is 0.085 ppm or greater, a violation of the ozone 

NAAQS has occurred. A violation of the eight-hour standard is determined on a per monitor 

basis. Monitor readings (and exceedances) at one location do not have any effect on the readings 

at another. 

The EPA was challenged in court on the new 8-hour standard, and the one-hour standard was 

reinstated. The Supreme Court upheld the constitutionality of 8-hour standard, but ruled that the 

EPA could not implement the new standard under subpart 1 of the CAA without considering the 

CAA’s subpart 2 requirements. Subpart 2 specifies area classification for nonattainment areas 

with additional control strategy requirements for each classification. The rule was remanded to 

the EPA in order to develop a reasonable approach to implement the new standard while 

considering the roles of subparts 1 and 2 in the implementation. 

Phase I of the Final Rule to Implement the 8-Hour Ozone National Ambient Air Quality 

Standard was released on April 30, 2004 [69 FR 23951] and became effective on June 15, 2004. 
6 

Phase II of the rule was published on November 29, 2005 [70 FR 71612] and became effective 

on January 30, 2006. These two rules provided specific obligations for state ozone plan 

revisions. Under these rules, the St. Louis 8-hour Ozone Nonattainment Area was subject to a 

number of obligations. 

1.2 Geographical Description of the St. Louis Nonattainment Area 

The St. Louis Ozone Area is a bi-state nonattainment area that violated the 1997 8-Hour Ozone 

Standard (see Figure 1-1). In April 2004, EPA designated the St. Louis area as nonattainment 

with a classification of moderate [69 FR 23858]. For more information on the NAAQS 

designation process, see paragraph 1.3.2 of this document. The following is a list of the counties 

contained in the St. Louis Missouri-Illinois 8-hour ozone nonattainment area: 

 St. Louis County, MO 

 St. Louis City, MO 

 St Charles, MO 

 Jefferson County, MO 

 Franklin County, MO 

 Madison County, IL 

 St. Clair County, IL 

 Monroe County, IL 

 Jersey County, IL 

Under the final implementation requirements, the St. Louis area was to demonstrate attainment 

of the 1997 8-hour ozone standard by June 15, 2010. On April 30, 2012, EPA published a final 

action that the St. Louis area attained the standard by this deadline date [77 FR 25363]. 
7 

Figure 1-1 1997 8-Hour Ozone Nonattainment Area for St. Louis (MO-IL) 

Region 
8 

1.3 St. Louis Ozone History 

1.3.1 One Hour Ozone Standard 

The Clean Air Act Amendments of 1990 (CAA) required states with nonattainment areas like St. 

Louis to develop revisions to the SIP to bring those areas into compliance. St. Louis was 

classified as a moderate ozone nonattainment area for the 1-hour standard. The CAA included 

very specific requirements for areas under each classification. The most important requirement 

for moderate areas was that attainment was to be achieved by 1996. Under the Amendments, 

failure to attain by the assigned date would result in reclassification to the more demanding 

classification of “serious.” Serious areas were subject to an additional set of requirements. 

St. Louis was required to achieve a minimum of 15 percent reduction in emissions of VOCs, and 

submit this Rate of Progress (ROP) plan for achieving that reduction. On November 15, 1993 the 

Air Program submitted an initial ROP plan. Subsequent amendments to the ROP plan were 

made in 1994, 1995, and 1996. These amendments were the result of refinements to inventory 

calculations and improvements in the documents. 

Although the ROP requirement was one of the key obligations of the CAA, the primary 

obligation was to develop a plan to achieve the national ozone standard in St. Louis. This plan is 

referred to as an attainment demonstration. An attainment demonstration was prepared and 

submitted to the EPA on October 25, 1995, which showed that the area would attain the air 

quality standard by 1996. The St. Louis area, however, failed to attain the 1-Hour ozone standard 

by 1996. The States of Missouri and Illinois proceeded with a request to extend the attainment 

deadline. 

To qualify for an attainment deadline extension, Missouri and Illinois had to demonstrate three 

requirements: that the area was significantly affected by ozone or ozone precursors transported 

from upwind sources; that all necessary local control measures have been implemented; and that 

the states had made the necessary administrative submittals. As part of this attainment date 

extension, additional photochemical grid modeling was conducted. This modeling included a 

number of regional control measures, in addition to the 15 percent ROP controls such as 

Reformulated Gasoline (RFG) and the enhanced Vehicle Inspection/Maintenance (I/M) 

programs. The attainment demonstration submitted as part of the 1-hour extension request 

focused on the evaluation of emission reductions that were expected from electric generating 

utilities resulting from EPA’s regional NOx SIP call. This SIP call resulted from EPA’s 

determination that ozone transport from one region to another interfered with some states’ ability 

to attain their ozone air quality goals. The NOx SIP call applied to twenty-two states in the 

eastern United States, and included emission reductions from sources located in the eastern onethird of Missouri. The study showed that both regional NOx controls and local VOC controls 

were necessary for attainment of the 1-hour standard, and that St. Louis was significantly 

affected by ozone transport and emissions from other states, and therefore, qualified for the 

attainment date extension. St. Louis was granted the extension, and subsequently attained the 1-

hour ozone standard. 
9 

1.3.2 1997 8-Hour Ozone Standard 

 1.3.2.1 1997 8-Hour Ozone Boundary Designations 

EPA promulgated the 8-hour ozone standard in June 1997. The new standard was set 0.08 parts 

per million (ppm) averaged over 8 hours and replaced the 1-hour ozone standard. An exceedance 

of the 8-hour ozone standard occurs when a monitor measures ozone above 0.084 ppm (per the 

rounding convention). A violation of the standard occurs when the average of the annual fourth 

highest daily maximum 8-hour ozone values over three consecutive years is greater than or equal 

to 0.085 ppm. This three-year average is called the design value for the monitor. The three-year 

period from 1997-1999 were used for the purposes of designation. The design value for the St. 

Louis Area was based on the monitor in the region with the highest design value. This monitor 

is located in West Alton, MO and had a three year design value of 0.95 ppm. Areas such as St. 

Louis which had design values that ranged from 0.92 to 0.107 ppm were classified as moderate 

ozone nonattainment areas. 

Boundary designation recommendations under the 1997 standard were developed using guidance 

published by EPA on March 28, 2000 and titled “Boundary Guidance on Air Quality 

Designations for the 8-Hour Ozone National Ambient Air Quality Standards.” The boundary 

recommendation for the 8-hour standard was identical to the old 1-hour boundary. It included 

the City of St. Louis and the counties of St. Louis, Franklin, Jefferson, and St. Charles. This 

recommendation was based on an in-depth technical evaluation based on EPA guidance. The Air 

Program sought stakeholder input. During the workgroup process, many complex issues were 

raised and discussed. 

In July 2000, on behalf of the Governor, the Air Program sent the original recommendation 

regarding the classification of counties under the revised ozone standard. These 

recommendations were based on EPA guidance released on June 25, 1999 and March 28, 2000. 

Based on 1997-1999 air quality data, the Air Program recommended the same boundary for the 

8-hour ozone nonattainment area as was used for the previous one-hour ozone nonattainment 

area. Based on the litigation surrounding the 1997 NAAQS (discussed in section 1.1) no formal 

action was taken on the initial boundary designation submittal. EPA requested updated, revised, 

or new designation recommendations and documentation from each state governor be submitted 

to the Regional Administrator by July 15, 2003. These recommendations were to be based on 

2000-2002 quality assured air quality monitoring data. 

Based on the input from stakeholders and the technical review, the Air Program presented a 

proposed boundary recommendation to the Missouri Air Conservation Commission (MACC) on 

June 26, 2003, and it was adopted on July 24, 2003. The nonattainment area boundary 

recommended remained unchanged from the 2000 recommendation and the 1-hour ozone 

designations. The Department submitted the recommendation to EPA on August 2, 2003. 

In letters received December 4 and 12, 2003, the EPA stated that they intend to modify the 

boundary recommendations for eight-hour ozone nonattainment areas. The EPA intended to 

modify the recommendation to include St. Genevieve County. In response to this EPA 

comment, the Department offered an alternative, involving addressing upwind NOX emissions 

rather than including all of Ste. Genevieve County. On March 25, 2004, the MACC signed a 

resolution committing the Department to promulgate a rule controlling emissions from large 
10 

NOx sources upwind and outside of the St. Louis nonattainment area. This rule, 10 CSR 10-

6.345 Control of NOx Emissions From Upwind Sources, was subsequently promulgated and 

became effective on December 30, 2006. 

On April 30, 2004, EPA classified the St. Louis area as a moderate nonattainment area for the 

new eight-hour ozone standard [69 FR 23858]. The area’s boundaries were designated as 

recommended and excluded Ste. Genevieve County. The state then had three years to develop 

the St. Louis nonattainment area 8-Hour Ozone SIP Revision. 

1.3.2.2. 1997 8-Hour Ozone Implementation Plan 

The EPA’s 8-hour ozone implementation rule required a number of elements for an approvable 

SIP revision. These elements included: an emissions inventory; attainment demonstration; 

Reasonably Available Control Technology (RACT) requirements; a ROP demonstration; a 

demonstration that New Source Review (NSR) permitting met all EPA requirements; motor 

vehicle emissions budgets to meet both the rate of progress and attainment; a discussion of 

specific individual area controls; and identification of contingency measures in case the area was 

not able to meet its attainment deadline. 

Extensive work, effort and resources were required to develop all elements of the 

implementation plan within the time frame established by EPA. The final result of the 

evaluations and the modeling of available data showed that the St. Louis Nonattainment Area 

would attain the 1997 standard by the 2010 deadline. 

Per the implementation rule, the RACT demonstration was required to be completed prior to 

other elements of the SIP revision. It was submitted to EPA following adoption by the MACC on 

December 6, 2006. All other required elements of the revision were submitted as part of, or 

concurrent with, the 2007 revision to the SIP. The I/M portion of the SIP was resubmitted as a 

separate revision at a later date due to subsequent changes that were made in the program as the 

result of new state laws. 

A public hearing of the 8-Hour ozone nonattainment plan SIP revision was held on April 26, 

2007, before the MACC. Comments were received from the EPA and the East-West Gateway 

Council of Governments. A number of document edits were made in response to these 

comments, but no substantive changes to control strategies were needed. These revisions were 

presented on May 31, 2007, and adopted by the Commission. 

The eight-hour ozone plan was submitted to the EPA on June 13, 2007, meeting the June 15, 

2007 federal deadline. The plan showed that the St. Louis non-attainment area will attain the 

1997 NAAQS for ozone by the 2010 deadline. 

 

Attainment of the 1997 NAAQS 8-Hour Ozone Standard was achieved following the 2009 ozone 

season, allowing for the development of a request for redesignation and maintenance plan. 
11 

1.3.3 New NAAQS Revision: 2008 8-Hour Ozone Standard 

On March 27, 2008, the U.S. Environmental Protection Agency (EPA) released a revised 8-hour 

ozone standard [73 FR 16436]. This revision lowers the ozone standard to 0.075 ppm (or 75 

ppb). 

With a revised NAAQS, the CAA requires states to review air quality monitoring data and 

submit ozone boundary designation recommendations. In March 2009, Missouri submitted its 

original boundary recommendation for the 2008 ozone NAAQS to EPA, based on the ozone air 

quality monitoring data for the three years of 2005–2007. Then in December 2011, Missouri 

updated the boundary recommendations based on air quality data for the three years of 2008–

2010. More information on Missouri’s boundary designation recommendations may be found at: 

http://dnr.mo.gov/env/apcp/naaqsboundarydesignations.htm.

On May 21, 2012, EPA finalized the area designations. The St. Louis area was designated 

nonattainment area and classified as marginal for the 2008 ozone standard [77 FR 30088]. The 

boundaries of the Missouri portion of the nonattainment area remained the same as for the 1997 

ozone standard but its classification changed from moderate. Marginal nonattainment areas have 

until December 31, 2015 to attain the 2008 Ozone NAAQS [40 CFR 51.1103]. 

Since the St. Louis Ozone Area is a bi-state nonattainment area, Illinois went through a similar 

designation process for its portion – the Metro-East side of the St. Louis area. For the Illinois 

portion under the 2008 ozone NAAQS, Jersey County is no longer designated as nonattainment 

as it was for the 1997 ozone standard. For more information on EPA’s final state designations, 

see - http://www.epa.gov/glo/designations/2008standards/state.htm. 

Lastly, because, air quality standards are periodically revisited pursuant to the CAA, another 

revision to the Ozone NAAQS is anticipated for 2015. 

1.4 Current Status / Background Summary: 1997 Ozone NAAQS 

On June 9, 2011, EPA published a final clean data determination in the Federal Register stating 

that the St. Louis ozone nonattainment area covering both Missouri and Illinois had attained the 

1997 8-hour ozone standard based on three consecutive ozone seasons (2008-2010) of qualityassured ambient air monitoring data [76 FR 33647, June 9, 2011]. On December 16, 2013, the 

Air Program submitted a letter to EPA certifying that the most recent three years (2011-2013) of 

quality-assured ambient air quality data is in compliance with the 1997 ozone NAAQS. 

Information regarding the air monitoring network and air quality monitoring data are included in 

chapter 3 of this document. 

CAA Section 107 establishes specific requirements to be met in order for a nonattainment area to 

be considered for redesignation. Clean air quality data is one of those requirements. The state 

must demonstrate that the improvement in air quality is due to permanent and enforceable 

reductions in emissions resulting from implementation of the SIP and other federal requirements. 

The development of a maintenance plan is another. This document addresses the maintenance 

plan requirements, and includes additional information on the permanent and enforceable 
12 

measures used to demonstrate attainment and continued compliance with the 1997 8-hour ozone 

NAAQS. 

In 2011, the Air Program submitted the first version of this redesignation/maintenance plan but 

the plan was not approved at that time due to litigation surrounding the federal interstate air 

pollution transport rules: CAIR & its successor, CSAPR. 

The District of Columbia Circuit Court ruled to vacate CSAPR and directed EPA to continue 

implementing CAIR while awaiting an acceptable replacement rule. Since CAIR remains in 

effect until the Supreme Court makes a decision or a satisfactory replacement rule is enacted, the 

emission reductions from CAIR are permanent and enforceable. 

As a result, in 2013, the Air Program decided to proceed once again with the redesignation 

request. This document serves that purpose as an updated revision to the original 2011 plan. 

More information on this may be found in the Foreword at the beginning of this document and 

elsewhere in this plan. 

Despite a newer more protective standard, the redesignation to attainment for the St. Louis area 

under the 1997 0zone standard, is important to — 

 Demonstrate that St. Louis metro ozone air quality concentrations are improving and are 

on a continued downward trend; 

 Show that air quality goals are being met in the St. Louis area as a result of permanent 

and enforceable emission reductions; 

 Establish a contingency plan that will act as a safeguard and backstop against potential 

future elevated ozone concentrations in the St. Louis area; and 

 Terminate uncertainty about future planning obligations under the 1997 Ozone NAAQS 

prior to it being revoked so that resources can be focused on the new more protective 

standard(s). 
13 

2. Redesignation and Maintenance Plan Requirements 

An area designated as nonattainment for a pollutant can be redesignated to attainment if specific 

conditions are met. Missouri has followed the EPA published Memorandum entitled, 

“Procedures for Requests to Redesignate Areas to Attainment”, from John Calcagni, Director, 

Air Quality Management Division, dated September 4, 1992, in preparing the redesignation 

demonstration and the maintenance plan. The memorandum provides guidance regarding the 

processing of requests for redesignation of nonattainment areas to attainment for ozone, carbon 

monoxide, particulate matter, sulfur dioxide, nitrogen dioxide, and lead. 

 Furthermore, the CAA, lists five (5) obligations that the EPA must meet during the 

redesignation process. Section 107(d)(3)(E) states: 

The Administrator may not promulgate a redesignation of a nonattainment area (or portion thereof) to 

attainment unless – 

(i) the Administrator determines that the area has attained the national ambient air quality standard; 

(ii) the Administrator has fully approved the applicable implementation plan for the area under section 

110(k); 

(iii) the Administrator determines that the improvement in air quality is due to permanent and enforceable 

reductions in emissions resulting from implementation of the applicable implementation plan and 

applicable Federal air pollutant control regulations and other permanent and enforceable reductions; 

(iv) the Administrator has fully approved a maintenance plan for the area as meeting the requirements of 

section 175A; and 

(v) the State containing such area has met all requirements applicable to the area under section 110 and part 

D. 

These five (5) obligations must be met before EPA can redesignate an area to attainment; 

however, a state may submit both the redesignation request and the maintenance plan at the same 

time so that rulemaking on both may proceed on a parallel track. This document outlines 

Missouri’s redesignation request and demonstrates how the state supports EPA’s promulgation 

obligations towards the redesignation of the St. Louis nonattainment area to attainment under the 

1997 ozone NAAQS. 

2.1 Attainment of the Standard 

CAA Section 107(d)(3)(E)(i) states that EPA must determine that the area is attaining the 

applicable NAAQS. For the 1997 NAAQS, this determination must be demonstrated using the 

design value based on the average of the last three (3) years’ 4th highest maximum daily 8-hour 

average concentrations. This design value must be lower than the level of the NAAQS, 0.08 

ppm. The state submitted a Clean Data Request to the EPA on December 4, 2009. On June 9, 

2011, EPA published a final clean data determination that the St. Louis ozone nonattainment area 

has attained the 1997 ozone standard [76 FR 33647] . Subsequently, on April 30, 2012, EPA 

stated that the St. Louis area had attained this standard by the three-years allowed after the 

moderate nonattainment classification pursuant to CAA Section 182(b) [77 FR 25363]. More 

information may be found in chapter 3 of this document which demonstrates how the St. Louis 

area has satisfied the redesignation requirement of CAA Section 107(d)(3)(E)(i) for NAAQS 

attainment. 
14 

2.2 Implementation Plan Approval 

The CAA requirement in Section 107(d)(3)(E)(ii) for redesignation states that the EPA 

administrator must have fully approved the applicable implementation plan for the area under 

Section 110(k). The 2007 Revision of the State Implementation Plan for the St. Louis 8-Hour 

Ozone Nonattainment Area was proposed for public hearing on April 26, 2007; was adopted by 

the MACC on May 31, 2007 and was submitted to the EPA on June 13, 2007. This ozone SIP 

was deemed to be complete on December 21, 2007. 

As stated earlier, EPA has published a final rule in the Federal Register stating that the St. Louis 

ozone nonattainment area covering both Missouri and Illinois has attained the 1997 8-hour ozone 

standard based on three years of quality assured ambient air quality data [76 FR 33647, June 9, 

2011]. Once an area attains the standard for a criteria pollutant, certain SIP element 

requirements that are developed to demonstrate and achieve attainment become unnecessary 

because the area has already attained the standard. These SIP elements that are tied to 

demonstration of attainment become suspended as long as the Clean Data Determination has not 

been rescinded. These particular SIP elements would never be required if the area is 

redesignated to a maintenance area for that pollutant. Guidance on this subject is found on page 6 

of the EPA’s Memorandum, Procedures for Requests to Redesignate Areas to Attainment, from 

John Calcagni, Director, Air Quality Management Division, dated September 4, 1992 which 

states “requirements for reasonable further progress ... will not apply for redesignations because 

they only have meaning for areas not attaining the standard.” 

This guidance is reaffirmed in EPA’s April 6, 2011 Memorandum from Janet McCabe, Deputy 

Assistant Administrator, Office of Air Quality Planning and Standards, titled Reasonable 

Consistency for the Administrative Requirements of State Implementation Plan Submittals and 

the Use of “Letter Notices”. Attachment C of the 2011 McCabe memo details that suspensions 

are only valid while the area is in compliance with the standard and how the suspended 

requirements are relieved: 

Upon EPA’s promulgation of a final Clean Data Determination for a nonattainment 

area, the obligation for the State to submit for such an area the attainment 

demonstration, associated reasonably available control measures, reasonable further 

progress plan, contingency measures, and other attainment-related planning 

requirements is suspended until such time as the area is redesignated to attainment, at 

which time the requirements no longer apply; or until EPA determines that the area has 

violated the NAAQS, at which time the obligations would again apply.

As such, on June 21, 2011, the state withdrew the above mentioned 8-hour Ozone Attainment 

Demonstration and Reasonable Further Progress Demonstration, because the area has already 

attained the NAAQS. All emission reductions and control measures from the plan remain in 

place as permanent and enforceable because they are based on federal or SIP-approved state 

regulations or consent agreements. By withdrawing the attainment demonstration, the EPA 

administrator was no longer required to approve or disapprove this plan. The attainment 

demonstration is no longer applicable because the area has attained the standard. Missouri has 

submitted to EPA all applicable SIP provisions to ensure the protection of the standard. See 

section 2.5 of this document for a discussion regarding the applicable SIP elements required 
15 

under Section 110 and Part D of the CAA for the Missouri portion of the St. Louis nonattainment 

area for the for the 1997 8-ozone NAAQS, and see chapter 4 of this document for a discussion 

regarding the control measures in Missouri’s SIP that were used to attain the 1997 ozone 

NAAQS. 

2.3 Permanent and Enforceable Improvement 

Redesignation requirement (iii) of CAA Section 107(d)(3)(E) states that EPA must determine 

that the improvement in air quality is due to permanent and enforceable reductions in emissions 

resulting from implementation of the applicable plan, applicable federal air pollutant control 

regulations and other permanent and enforceable reductions. Therefore, EPA must show that the 

improvement in air quality between the year that violations occurred, and the attainment year, is 

attributed to permanent and enforceable emission reductions. Chapter 4 of this document 

presents the emission reductions that were achieved from federal and state measures in the St. 

Louis area. The emission reductions are not based on temporary shutdowns or adverse economic 

conditions, but due to permanent and enforceable control measures. This plan includes a state 

commitment to continue to enforce all applicable requirements of past revisions to the SIP after 

the St. Louis ozone nonattainment area is redesignated to attainment thus satisfying CAA 

107(d)(3)(E)(iii). 

2.4 Maintenance Plan Requirements 

The CAA redesignation requirement of Section 107(d)(3)(E)(iv) states that EPA must have a 

fully-approved maintenance plan for the area as meeting the requirements of CAA Section 175A. 

Under Section 175A, this 8-Hour Ozone Maintenance Plan is the State’s SIP revision to provide 

for continued attainment of the 1997 8-hour ozone NAAQS for the St. Louis nonattainment area 

for a period of at least ten years after EPA has formally redesignated the area to attainment. This 

maintenance plan and redesignation request has been prepared in accordance with the 

requirements specified in EPA’s guidance documents and in coordination with EPA Region 7 

staff. Section 2.4 addresses how the following required maintenance plan elements of CAA 

Section 175A have been met in the subsequent correspondingly-numbered paragraphs: 

1. A public hearing on the maintenance plan prior to adoption; 

2. A comprehensive emissions inventory of the precursors of ozone completed for 

the “attainment year”; 

3. A projection of the emissions inventory forward to a year at least ten years after 

redesignation and a demonstration that the projected level of emissions is 

sufficient to maintain attainment of the ozone NAAQS; 

4. A commitment that, once redesignated, the state will continue to operate an 

appropriate monitoring network to verify maintenance of the attainment status; 

5. A demonstration of legal authority to implement and enforce all control measures 

contained in the SIP; 

6. Provisions for future updates of the inventory to enable tracking of emissions 
16 

levels, including an annual emissions statement from major sources; 

7. Motor vehicle emissions budgets (MVEBs) for transportation conformity for the 

ten-year maintenance period; 

8. A commitment to submit a revised maintenance plan eight years after 

redesignation; 

9. A list of potential contingency measures and a commitment to enact and 

implement these measures expeditiously in the event that future violations of the 

NAAQS occur. 

2.4.1 Public Participation 

In accordance with Section 110(a)(2) of the CAA, the State of Missouri held a public hearing 

prior to adoption of this maintenance plan and the subsequent submittal to the EPA. The Air 

Program notified the public and other interested parties of an upcoming public hearing and 

comment period thirty (30) days prior to holding such hearing for this maintenance plan as 

follows: 

 Notice of availability of the redesignation request and maintenance plan was posted on 

the Department of Natural Resources’ Air Pollution Control Program website on 

February 24, 2014: http://www.dnr.mo.gov/env/apcp/stateplanrevisions.htm

 A public hearing date to receive comments on the redesignation request and maintenance 

plan was held on March 27, 2014 beginning at 9:00 am at the Lamplighter Inn, Missouri 

Two Meeting Room, 2820 N Glenstone Avenue, Springfield, MO 65803. 

 

 A public comment period was opened after the redesignation request and maintenance 

plan was posted on the Department of Natural Resources’ Air Pollution Control Program 

website on February 27, 2014 and closed on April 3, 2014, seven (7) days after the public 

hearing. 

Comprehensive “Attainment Year” Emissions Inventory of Ozone Precursors 

The state has developed a comprehensive emission inventory for the St. Louis ozone 

nonattainment area which includes the emissions from the following four source categories: 

point sources, area sources, on-road mobile sources and off-road mobile sources. The attainment 

year emission inventory, as required in the maintenance plan, is detailed in chapter 5 of this 

document. 

Projected Emission Inventory for 2025 

The state has compiled a list of growth and control factors and developed a county-level 

emission inventory for the future year of 2025 for the Missouri portion of the St. Louis 

nonattainment area. These projected emissions show substantial decreases between 2008 and 

2025 in cumulative emissions that contribute to ground-level ozone concentrations in the 

ambient air. This future year emission inventory is detailed in chapter 5 of this document and the 
17 

state asserts that these projected future emission levels are sufficient to maintain attainment of 

the 1997 8-hour ozone NAAQS. 

2.4.4 Continued Monitoring Commitment 

The State of Missouri is committed to continue monitoring ambient ground-level ozone 

concentrations in the St. Louis area and throughout the state in accordance with 40 CFR Part 58 

and EPA approved Annual Monitoring Plans. Missouri will continue to quality assure the 

ambient air monitoring data in accordance with 40 CFR 58 and submit the data into the AQS in a 

timely fashion. Detailed information about the ground-level ozone monitoring network in the St. 

Louis nonattainment area, along with further discussion about the state’s continued monitoring 

commitment, can be found in chapter 3 of this document. 

2.4.5 Legal Authority to Implement and Enforce 

The Missouri Air Conservation Commission has the legal authority to develop, implement, and 

enforce regulations regarding air pollution including the requirements of this SIP submittal under 

Section 643.050 of the Revised Statues of Missouri, also known as the Missouri Air 

Conservation Law. 

2.4.6 Provisions for Future Updates to the Emission Inventory 

The State of Missouri is committed to provide future inventory updates to enable tracking of 

emissions levels during the 10-year maintenance period. State Regulation 10 CSR 10-6.110, 

Reporting Emissions Data, Emission Fees, and Process Information, requires that all 

installations located in the state that are required to obtain air quality construction or operating 

permits must report their annual emissions to the Air Program. The methods for calculating and 

reporting their emissions are detailed in each installation’s applicable permit. The data collected 

on emissions inventory questionnaires from permitted sources form the basis of the point source 

emissions inventory that is compiled on an annual basis. In addition, in compliance with the 

Federal Air Emission Reporting Rule [73 FR 76539], the Air program develops a comprehensive 

emissions inventory of point, area, and mobile sources every three years. 

2.4.7 Motor Vehicle Emission Budgets 

The establishment of motor vehicle emission budgets (MVEBs) for the 1997 ozone NAAQS is 

no longer necessary with the revocation of the 1997 ozone NAAQS for Transportation 

Conformity purposes [77 FR 30160]. 

However, the State of Missouri has developed MVEBs for the (newer) 2008 ozone NAAQS in 

its Early Progress Plan [http://www.dnr.mo.gov/env/apcp/docs/complete-epp-submittal-8-16-

13.pdf]. EPA has deemed these budgets to be adequate in a letter dated November 28, 2013. 

East-West Gateway Council of Governments, the metropolitan planning organization for the 

greater St. Louis area, has already started using these MVEBs for the revised ozone standard in 

their most recent Transportation Conformity determination cycle. It should be noted that the 

2008 ozone NAAQS is exactly the same form, but more stringent in concentration, than the 1997 

ozone NAAQS. More information on Transportation Conformity may be found in chapter 6 of 

this document. 
18 

2.4.8 Commitment to Revise Plan 

Under CAA Section 175A, an area designated as maintenance for a NAAQS is required to 

submit a second maintenance plan eight (8) years after redesignation of any area as an attainment 

area under Section 107(d). This second maintenance plan is intended to maintain the NAAQS 

for ten (10) years after the expiration of the initial ten year period. The Air Program recognizes 

the importance of an up-to-date, current maintenance plan, and commits to updating it as 

necessary. 

2.4.9 Contingency Measures 

The State of Missouri is committed to maintaining compliance with the 1997 8-hour ozone 

standard. If future violations of the standard take place, the state will enact contingency 

measures as expeditiously as possible, that will allow for the area to come back in compliance 

with the standard as quickly as feasible. Further information about this commitment to enact 

contingency measures, and a potential list of contingency measures that would be evaluated if 

the area falls out of compliance with this standard in the future are located in chapter 7 of this 

document. 

2.5 Section 110 and Part D Requirements 

The CAA requirement in Section 107(d)(3)(E)(v) for redesignation states that, all the 

requirements of Section 110 Implementation Plans and Part D of the CAA that were applicable 

prior to submittal of a complete redesignation request must be met. 

2.5.1 Section 110 Requirements 

On May 8, 2007, EPA approved the Missouri SIP to address the requirements of Section 

110(a)(2)(D)(i) of the CAA for the 1997 8-hour ozone NAAQS [72 FR 25975]. In addition EPA 

approved Missouri’s SIP submission addressing the remaining ozone NAAQS infrastructure SIP 

elements of CAA 110(a)(2) for the entire state on July 11, 2011 [76 FR 40619]. All other CAA 

Section 110 provisions are administrative, procedural or options that do not require a submission 

on behalf of the State. 

2.5.2 Part D Requirements 

Certain requirements under Part D of the Clean Air Act (Nonattainment Plan Provisions) are 

suspended when a nonattainment area achieves the NAAQS because these requirements are 

related to the attainment of the air quality goal as discussed above in section 2.2 of this 

document. Thus the intention of these requirements has been fulfilled with attainment of the 

NAAQS without the necessity of further submittals as long as the area’s Clean Data 

Determination has not been rescinded. 

Other requirements under Part D of the Clean Air Act remain applicable despite the clean data 

determination because they are not directly related to attainment of the NAAQS. The Part D 

elements that are relevant and applicable to this redesignation process are found in CAA Sections 

172(c) and 182(b). Section 172(c) pertains to nonattainment plan provisions for all NAAQS, 

while 182(b) elements are specific to moderate ozone nonattainment areas such as the St. Louis 

area under the 1997 NAAQS. The list below outlines the pertinent elements of these two CAA 

sections that remain applicable to the St. Louis moderate ozone nonattainment area under the 
19 

1997 NAAQS despite the Clean Data Determination along with a statement of how each element 

is addressed: 

 Section 172(c)(3) Emissions Inventory (& Section 182(a)(1) Inventory): The 2002 Base 

Year Inventory for the Missouri Portion of the St. Louis Ozone Nonattainment area was 

approved on May 31, 2007 [72 FR 30272]. See section 4.1.

 Section 172(c)(5) Permitting Requirements (& Section 182(a)(2)(C) Permitting 

Programs): Missouri has a long-standing and fully-implemented New Source Review 

(NSR) permitting program for new major sources and significant modifications of 

existing sources under State rule 10 CSR 10-6.060, Construction Permits Required. See 

section 5.4. 

 Section 182(b)(2) Reasonably Available Control Technology: The St. Louis ozone 

moderate nonattainment area has an approved VOC RACT Demonstration [79 FR 580] 

and a NOx RACT waiver [76 FR 43598] for the 1997 ozone NAAQS. See section 4.3. 

 Section 182(b)(3) Gasoline Vapor Recovery: The St. Louis moderate ozone 

nonattainment area has a refueling vapor recovery program implemented through State 

rule 10 CSR 10-5.220 Control of Petroleum Liquid Storage, Loading and Transfer. The 

Air Program is currently developing a revision to this rule to account for the federal 

declaration of widespread use of onboard refueling vapor recovery (ORVR) technology 

and Stage II waiver [77 FR 28772, May 16, 2012]. See paragraph 5.1.2. 

 Section 182(b)(4) Motor Vehicle Inspection and Maintenance: The 

Inspection/Maintenance (I/M) program for the St. Louis moderate ozone nonattainment 

area, known as the Gateway Vehicle Inspection Program (GVIP), is established by State 

rule 10 CSR 10-5.381 On-board Diagnostics Motor Vehicle Emissions Inspection. 

 Section 182(a)(3)(B) Emissions Statements: The State complies with this requirement 

that stationary sources report their actual annual emissions of NOx and VOCs through 

State rule 10 CSR 10-6.110 Reporting Emission Data, emission Fees, and Process 

Information. This obligation was deemed satisfied and approved into the SIP along with 

the 2002 Emissions Inventory mentioned above on May 31, 2007 [72 FR 30274]. 
20 

3. Ozone Monitoring 

Note: This chapter refers to ozone air quality monitoring data specifically for the years 2008-

2010 as this is the three-consecutive year period upon which the original 2011 maintenance plan 

and redesignation request was based and the Clean Data Determination was made. An update 

for the most recent three-year period is found in section 3.7 of this document and a summary of 

recent years’ ozone data may be found at http://dnr.mo.gov/env/apcp/docs/ozonemonitordata.pdf. 

This chapter presents monitoring information that demonstrates St. Louis has attained the 1997 

8-hour ozone standard of 0.08 ppm. As mentioned in chapter 2 of this document, attaining the 

NAAQS is one of the requirements for an area to be redesignated to attainment [CAA Section 

107(d)(3)(E)(i)]. This demonstration is based on three consecutive ozone seasons of quality 

assured data monitored at the St. Louis ozone monitoring network as specified in 40 CFR 58. 

The ambient air quality monitoring data demonstrates that the area has attained the applicable 

NAAQS consistent with methods cited in the EPA guidance document: “Procedures for 

Processing Request to Redesignate Areas to Attainment”. The following are requirements for the 

use of ambient air monitoring data in demonstrating that the area is attaining the applicable 

NAAQS: 

 Monitoring data must show that the non-attainment area is attaining the NAAQS. 

 The data should be collected and quality assured in accordance with 40 CFR 58 and 

recorded in the U.S. EPA Air Quality System (AQS) database in order for it to be 

available to the public for review. 

3.1 St. Louis Ozone Monitoring Network 

In 2010, there were 15 sites that monitored ozone in the St. Louis Region. 11 of these sites are 

located within the St. Louis nonattainment area; 6 in Missouri and 5 in Illinois. In addition, 

Missouri and Illinois operate at least a monitor upwind and downwind of the nonattainment area. 

The upwind monitors are located in Bonne Terre, Ste. Genevieve County, Missouri and in 

Hickory, Randolph County, Illinois. Downwind monitors outside of the nonattainment area are 

located in Foley, Lincoln County, Missouri and Nilwood, Macoupin County, Illinois. Figure 3-1 

shows all monitors in the St. Louis Ozone Monitoring Network. 
21 

Figure 3-1 St. Louis Ozone Monitoring Network 

3.2 Ambient Air Monitoring Data 

As previously mentioned, exceedances of the standard are determined on a per monitor basis. 

An exceedance of the standard occurs any time that an 8-hour average value is greater than 0.084 

ppm. A monitor can exceed the 8-hour standard and not violate the standard. A violation of the 

standard at a specific monitor is determined by taking the fourth-highest, eight-hour average 

reading at a monitor for each of three consecutive years and averaging them together. The eighthour ozone standard is 0.08 ppm and, due to rounding, a monitor must have a fourth highest 

eight-hour, three-year average reading of 0.085 ppm (85 parts per billion, or ppb) or higher for it 

to be considered a violation of the standard. 

Design values are calculated by averaging the annual fourth-highest daily maximum 8-hour 

ozone concentrations over the three consecutive years (40 CFR Part 50). The standard at a site is 

met when the site’s design value is less than or equal to 0.084 ppm (84 ppb). Design values are 

used as indicators of a region’s air quality. The higher a design value for a monitor, the poorer 

the air quality is in that area. Along the same lines, if an area shows an increasing design value 

over a number of years, monitoring data is indicating that the air quality is worsening. 
22 

Figures 3-2 and 3-3 show the design value trends for the monitors in the Missouri portion of the 

St. Louis nonattainment area and the Illinois portion of the St. Louis nonattainment area, 

respectively. As indicated by the trends in the figures, ozone concentrations have decreased at all 

monitors, indicating improved air quality throughout the St. Louis region. Within the Missouri 

portion of the St. Louis nonattainment area, there were a total of 11 sites that violated the 1997 

standard according to 2001-2003 air monitoring data (Figure 3-2). During the same time period 

of 2001-2003, two sites in the Illinois portion of the St. Louis nonattainment area also violated 

the 1997 standard (Figure 3-3). As of the three-consecutive year period ending in 2010, all sites 

in the area, , were in compliance of the standard, as shown by the design value data in Figures 3-

2 and 3-3, as well as the comparison maps in Figure 3-4. Sites that have been discontinued or 

relocated show design values below the standard at the time of discontinuance or relocation 

(Figures 3-2 and 3-3). 
23 

Figure 3-2 2001-2010 8-hour Ozone Design Value Trends - MO 

St. Louis Nonattainment Area, MO (1997 NAAQS = 84 ppb) 

 
24 

Figure 3-3 2001-2010 8-hour Ozone Design Value Trends - IL 

St. Louis Nonattainment Area, IL (1997 NAAQS = 84 ppb) 
25 

Figure 3-4 2001-2003 & 2008-2010 Design Values Comparison 

St. Louis Nonattainment Area 8-hour Ozone Design Values (1997 NAAQS = 84 ppb) 

2001-2003 Design Values 

2008-2010 Design Values 
26 

3.3 St. Louis Ozone Monitoring Data Analysis 

The St. Louis area’s compliance with the 1997 ozone NAAQS is determined by comparing the 

area’s calculated design values to the ozone standard. As described previously, design values are 

calculated at each monitor by averaging the annual fourth-highest daily maximum 8-hour ozone 

concentrations over the three consecutive years (40 CFR Part 50). The standard at a site is met 

when the site’s design value is less than or equal to 84 ppb. 

The design value for the entire St. Louis nonattainment area is determined by comparing all of 

the design values for the monitors in the nonattainment area. The area’s design value is 

determined by the single highest individual monitor’s design value for each three consecutive 

ozone season averaging period. The area’s status of attainment or nonattainment is determined 

by this design value. For the eight-hour ozone standard, the design value at all monitors for the 

three-year time periods from 2008 through 2010 did not exceed 0.084 ppm, and thus achieved 

attainment for the St. Louis nonattainment area. The calculated 2008-2010 8-hour design values 

for sites in the St. Louis nonattainment area are presented in Table 3-1. As shown in the table, all 

sites three-year design values are less than the 1997 standard, demonstrating that the St. Louis 

area has attained the 8-hour air quality standard. The St. Louis nonattainment area’s design 

value monitor would be the West Alton monitor, due to its design value being the highest. The 

West Alton monitor is bold in Table 3-1. 

Table 3-1 2008-2010 St. Louis 8-Hour Design Values 

(1997 NAAQS = 84 ppb) 

County Monitoring Sites 

2008 

4th

High 

2009 

4th

High 

2010 

4th

High 

2008-2010 

Design Value 

 Missouri 

St. Charles Orchard Farm 72 73 77 74 

St. Charles West Alton 76 71 84 77 

St. Louis City Blair Street 73 65 71 69 

St. Louis Maryland Heights 69 70 76 71 

St. Louis Pacific 64 64 69 65 

Jefferson Arnold West 70 70 77 72 

3.4 Missing Data Under the 1997 8-Hour Ozone Standard 

Eight-hour ozone attainment is determined by a three-year average of the annual fourth highest 

daily maximum. Missing days are of importance only in determining whether sufficient data 

was sampled to determine compliance. A monitoring day must include 18 valid eight-hour 

averages for a daily maximum to be determined. To calculate a design value, an average of 90% 

of the possible daily maximums over a three year period must be complete, with no single year 

having less than 75% completeness. The final result is that no more than 53 missed days in one 

year, or 64 missed days total for the three-year period are allowed. If these criteria are not met, 

then compliance with the 8-hour ozone standard cannot be established. To date, acceptable 

monitoring has been maintained and exceeded in the Missouri portion of the St. Louis 

nonattainment area for the 8-hour ozone standard. 
27 

3.5 Quality Assurance Program 

Ambient air monitoring data from the Missouri ozone network is quality assured in accordance 

with 40 CRF Part 58 and the Missouri Quality Assurance Project Plan (QAPP). The QAPP 

outlines standard operating procedures for operating the network and validating the data. In 

addition the network is reviewed annually through the Annual Monitoring Plans, according to 40 

CFR Part 58.10. A site can either be discontinued or relocated based on the annual review and 

with an approval from the EPA. The quality assured data collected at the sites is submitted in the 

Air Quality System (AQS) and is available for public review as outlined in 40 CFR Part 58. 

Illinois EPA follows a similar quality assurance system. 

3.6 Continued Monitoring Commitment 

The Air Program is committed to continue operating the appropriate ozone network in the St. 

Louis area, in accordance with 40 CFR 58 and approved Annual Monitoring Plans, to verify the 

attainment status of the area. Missouri will continue to quality assure the ambient air monitoring 

data in accordance with 40 CFR 58 and submit the data to AQS in timely fashion. 

The St. Louis Metropolitan Statistical Area (MSA) satisfies and exceeds the minimum 

monitoring requirement for ozone [40 CFR 58 Appendix D, Table 2], revisions to the Ambient 

Air Monitoring Regulations [71 Federal Register 61240, October 17, 2006] note that – 

While the final rule of regulations requires fewer monitors than are now operating for 

ozone and PM2.5, as did the pre-existing monitoring rule, EPA does not intend to 

encourage net reductions in the number of ozone and PM2.5 monitoring sites in the U.S. 

as a whole. The surplus in the existing networks relative to minimum requirements gives 

States more flexibility to choose where to apply monitoring resources for ozone and 

PM2.5. 

The Air Program is committed to continue monitoring ozone ambient air concentrations in the 

St. Louis area and throughout the state in accordance with 40 CFR Part 58 and EPA-approved 

Annual Monitoring Network Plans. Missouri will continue to quality assure the ambient air 

monitoring data in accordance with 40 CFR 58 and submit the data into the AQS in a timely 

fashion. Missouri’s most recent proposed air quality monitoring network plan is available at: 

http://dnr.mo.gov/env/apcp/monitoring/monitoringnetworkplan.pdf. Also, visit EPA Region 7’s 

Air Quality Monitoring Network plan site for more information or to review Missouri’s previous 

approved network plans: http://www.epa.gov/region07/air/quality/quality.htm#mo_air. 

3.7 Clean Data Determination 

On June 9, 2011, EPA published a final clean data determination in the Federal Register stating 

that the St. Louis ozone nonattainment area covering both Missouri and Illinois has attained the 

1997 ozone standard based on three years of quality assured ambient air monitoring data [76 FR 

33647]. Subsequently, EPA also determined that the St. Louis area had attained this standard by 

the regulatory deadline of June 15, 2010 [77 FR 25363, April 30, 2012]. On December 16, 2013, 

the Air Program submitted a letter to EPA certifying that the most recent three years (2011-2013) 

of quality-assured ambient air quality data is in compliance with the 1997 ozone standard. 
28 

4. Redesignation Request: Emission Inventory and Controls from 

2002 - 2008 

A redesignation request must contain a demonstration that the improvement in air quality, 

between the year that violations occurred and the year that attainment was achieved, is based on 

permanent and enforceable emissions reductions. As described previously in chapter 3, threeconsecutive ozone season monitoring periods are used to evaluate whether actual air quality 

attainment has been achieved. In this chapter, the “attainment year” refers to the first year 

(2008) of the three-year period (2008-2010) used to demonstrate attainment, and the base year 

refers to the mid-point year (2002) of the three-year period used to determine the nonattainment 

designation. The inventories detailed in this chapter for 2002 and 2008 include data categories 

for point, area, on-road mobile, and non-road emissions for NOx and VOC. Additional details 

for the base and attainment year inventories for 2002 and 2008 are found in Appendices A and B, 

respectively. 

4.1 Base Year and Attainment Year Inventories 

Table 4.1 is a comprehensive emissions inventory for the Missouri side of the St. Louis 

nonattainment area, including point, area, on-road mobile, and non-road sources for precursors of 

ground-level ozone (NOx and VOC) for the base year, 2002. Table 4.2 summarizes the 

emissions inventory for the Missouri side of the St. Louis nonattainment area for NOx, and VOC 

for the attainment year, 2008. Both the 2002 and 2008 inventories are based on actual activity 

levels. 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]. Therefore, this section only includes emissions inventories for the Missouri portion of 

the nonattainment area. The emissions inventories for the years 2002 and 2008 for the Illinois 

portion of the nonattainment area, which were included in Illinois’ maintenance plan, are 

provided for reference in Appendix H. 

The 2002 base year inventory includes emissions from point, area, on-road mobile and non-road 

emissions. Table 4.1 states the 2002 emissions in tons/ozone season day, and summarizes the 

emissions by major source category and by pollutant for the St. Louis nonattainment area. 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. 

The 2008 emissions inventory listed in this chapter is listed in tons/ozone season day. In order to 

calculate the emissions in tons/ozone season day for the Missouri portion of the ozone 

nonattainment area, the Air Program followed the methods listed in Appendix B of this 

document. Briefly, for point sources, ozone season day emissions are calculated on the EIQ 

form 2.0Z, Ozone Season Information. The facility-reported maximum daily throughput during 

the ozone season is multiplied by the pollutant emission factor and reduced by control device to 

reach the ozone season daily emissions. For area sources, 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. See Appendix B-7 for the temporal allocation method tables. Appendix B-7 
29 

outlines this procedure for area sources, and gives an example. Non-road ozone season day 

emissions may be found in Appendix B-6. 

Finally, for on-road mobile sources, emissions were created using Mobile6.2 via the National 

Mobile Inventory Model (NMIM) with 2008 vehicle miles traveled (VMT) data provided by the 

East West Gateway Council of Governments in coordination with the Interagency Council of 

Governments. The 2008 VMT data was generated from East-West Gateway's Traffic Demand 

Model and then compared to Highway Performance Monitoring System (HPMS) data. Through 

this comparison, calibration factors were developed and then applied to the VMT data from the 

Traffic Demand Model in order to estimate the actual 2008 VMT for the St. Louis nonattainment 

area. The NMIM National County Database (NCD) was updated with Missouri specific data. 

Please see Appendix B-4 for additional details regarding the 2008 on-road mobile emissions 

calculated using Mobile 6.2 via NMIM. 

The EPA’s Mobile6.2 emissions model was used to generate the mobile source emissions in this 

chapter in order to allow for a useful comparison between 2002 and 2008 mobile emissions. The 

mobile emissions generated for the 2002 emissions inventory used Mobile6.2, and it was 

necessary to use the same mobile emission model to compare the base and attainment year 

mobile source emissions. However, in chapter 5 of this document, the 2008 and 2025 mobile 

source emissions were generated using EPA’s Motor Vehicle Emissions Simulator (MOVES). 

More information about the use of these two different emission models can be found in chapter 5 

and Appendix B-5 of this document. 

Tables 4-1 and 4-2 summarize the 2002 and 2008 average daily ozone season NOx and VOC 

emissions from the Missouri side of the St. Louis ozone nonattainment area, respectively. Table 

4.3 shows the differences in inventories between these two years for each source category and 

pollutant of concern. As seen in Table 4-3, NOx emissions decreased by 121 tons per ozone 

season day, which is a reduction by nearly 1/3 (33%) from the 2002 levels. Meanwhile, total 

VOC emissions remained relatively stable, increasing by only 1.4 tons/day, which is less than 

1%. As can be seen, VOC emissions decreased for every category except for area sources. The 

area source VOC increase is due to a change in the reporting of small, non-Title-V-permitted 

sources from the point category in 2002 to the nonpoint category in 2008, as well as numerous 

changes in the area source estimation methodologies and emission factors. The substantial 

reduction in NOx emissions between 2002 and 2008, along with other regional controls have 

resulted in the improved monitored ground-level ozone concentrations in the St. Louis 

nonattainment area attributable to the 1997 ozone NAAQS compliance.

Table 4-1. 2002 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Source Category NOx VOC 

Point Sources 127.2 32.7 

Area Sources 19.4 71.3 

On-Road Mobile Sources 159.0 68.1 

Non-Road Sources 60.7 47.0 

Total 366.3 219.1 
30 

Table 4-2. 2008 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Source Category NOx VOC 

Point Sources 88.8 18.0 

Area Sources 6.5 99.5 

On-Road Mobile Sources 96.2 57.9 

Non-Road Sources 53.6 45.2 

Total* 245.2 220.5 

*Note: Values may not total exactly due to rounding. 

Table 4-3. Comparing 2002 and 2008 VOC and NOx Emissions for the Missouri Side of 

the 1997 St. Louis 8-Hour Ozone Nonattainment Area (tons per ozone season 

day) 

Source Category NOx VOC 

Point Sources* -38.4 -14.7 

Area Sources* -12.9 +28.2 

On-Road Mobile Sources* -62.8 -10.2 

Off-Road Mobile Sources* -7.1 -1.8 

Total** -121.1 +1.4 

*Note: A negative value indicates a decrease in emissions from 2002 to 2008. 

 A positive value indicates an increase in emissions from 2002 to 2008. 

**Note: Values may not total exactly due to rounding. 

4.2 Permanent and Enforceable Controls Used to Attain the Standard 

The St. Louis area was designated as nonattainment of the 1997 8-hour ozone NAAQS in 2004. 

Since that time, the implementation of permanent and enforceable reductions of NOx and VOC 

emissions have contributed to improvements in ground level ozone concentrations and to the 

attainment of the 1997 8-hour ozone NAAQS. The primary control measures used to attain the 

1997 8-hour ozone standard include: 

 New Source Performance Standards (NSPS) 

 National Emissions Standards for Hazardous Air Pollutants (NESHAPS)/Maximum 

Achievable Control Technology (MACT) Standards 

 Federal gasoline detergent additive rule 

 NOx SIP Call 

 Clean Air Interstate Rule (CAIR) 

 Heavy-Duty Diesel Engine Standards 

 Tier 2 Rule-Vehicle Standards 

 Tier 4 Rule-Off Road Mobile Engine Standards 

 Reformulated Gasoline (RFG) 

 Gateway Vehicle Inspection Program 
31 

 National VOC Emission Standards for Consumer and Commercial Products (Part 59) 

o Automobile Refinishing Rule 

o Architectural and Industrial maintenance coating rule 

o Consumer Products solvent control rule 

 Missouri State Rules 

4.2.1 Federal Emission Trading Programs and the NOx SIP Call 

The NOx SIP Call and CAIR required states to reduce emissions that are prohibited by the 

interstate transport provisions of the Clean Air Act Section 110(a)(2)(D)(i)(I). Both rules also 

established emission trading programs that states could use to reduce the transport of emissions 

that have significant impacts on downwind nonattainment and maintenance areas. 

One outcome of the NOx SIP Call was the establishment of the NOx Budget Trading Program 

(NBP). The first year in which covered sources were required to comply with the NBP was 

2003. Missouri complied with the requirements of the NBP through state rule 10 CSR 10-6.360 

Controlling NOx Emissions From Electric Generating Units and Non-Electric Generating 

Boilers, which required applicable sources in the eastern third of the state to participate in the 

NBP. Implementation of the NBP greatly reduced ozone season NOx emissions from large 

sources such as electric generating units (EGUs). According to data from CAMD’s Website, the 

total ozone season NOx emissions from EGUs located in the St. Louis nonattainment area have 

been reduced by 4,942 tons (approx. 32.3 tons/ozone season day) from 2002 to 2008. These 

reductions are almost exclusively attributed to implementation of the NBP. In Missouri, three 

non-EGU boilers also participated in the NBP, specifically Trigen Units 5 and 6 and Anheuser 

Busch Unit 6. 

Also in response to the NOx SIP Call, three other State rules were developed to control ozone 

season NOx emissions from covered sources in the eastern third of the state. The rules written to 

comply with the NOx SIP Call requirements include the statewide NOx rule 10 CSR 10-6.350 

Emissions limitations and Emissions Trading of Oxides of Nitrogen, which established a 

statewide NOx trading program for EGUs, 10 CSR 10-6.380 Control of NOx Emissions From 

Portland Cement Kilns, which controls ozone season NOx emissions from cement kilns, and 10 

CSR 10-6.390 Control of NOx Emissions From Large Stationary Internal Combustion Engines. 

From 2002 to 2008, the NOx emission reductions from all point sources in the nonattainment 

area totaled 38.4 tons /ozone season day. This accounts for a more than 30% reduction. 

CAIR, which was promulgated several years after the NOx SIP Call, established three emission 

trading programs that states could use to address transported emissions – the CAIR NOx ozone 

season trading program, the CAIR annual NOx trading program and the CAIR SO2 trading 

program. The CAIR ozone-season NOx trading program replaced the NBP and the statewide 

NOx rule (10 CSR 10-6.350). In the St. Louis area, the CAIR ozone season NOx trading program 

required the same EGUs and the same three non-EGU boilers mentioned above to participate as 

were required under the NBP. However these three units have all been retired and received 

retired unit exemptions that prohibit these units from operating. The signed EPA retired unit 

exemption forms for these three units are included in this document as Appendix F. 
32 

The CAIR ozone-season NOx trading program, along with the CAIR annual NOx trading 

program began in 2009. In regards to the EGUs located in the St. Louis nonattainment area, the 

ozone season NOx requirements in CAIR were comparable to the requirements under the NOx

SIP Call. However, CAIR had a significant impact on the EGUs located in the western twothirds of the state, and these sources significantly reduced their ozone season NOx emissions. 

Some of the facilities in the western two-thirds of the state installed controls earlier than 2009 in 

anticipation of CAIR. While the NOx controls added in the western two-thirds of the state do not 

affect the NOx emissions inventory for the St. Louis nonattainment area, they did have a positive 

impact in reducing the transported or regional contribution of NOx emissions to the ozone 

monitors located in the nonattainment area. 

It was anticipated that EPA’s Cross-State Air Pollution Rule (CSAPR) would replace the CAIR 

trading programs beginning January 1, 2012. EPA promulgated CAIR on May 12, 2005 and the 

CAIR federal implementation plans on April 26, 2006. In 2008, the US Court of Appeals for the 

DC Circuit remanded CAIR to the agency, and EPA finalized CSAPR to replace CAIR on July 

6, 2011. However, prior to CSAPR implementation, the District of Columbia Circuit Court of 

Appeals stayed the implementation of CSAPR in December 2011. The court directed EPA to 

continue implementing CAIR until the legal decision regarding CSAPR is resolved. In August 

2012, the U.S. District of Columbia Circuit Court of Appeals issued a decision vacating CSAPR 

and directed EPA to continue to implement CAIR until they can implement a replacement rule 

that addresses the Court’s concerns. 

Furthermore, on November 19, 2012, EPA’s Assistant Administrator Gina McCarthy issued a 

memorandum regarding Next Steps for Pending Redesignation Requests and State 

Implementation Plan Actions Affected by the Recent Court Decision Vacating the 2011 CrossState Air Pollution Rule: 

http://www.epa.gov/airquality/transport/pdfs/CSAPR_Memo_to_Regions.pdf. In this memo, 

EPA referred to a number of various pending redesignation requests, maintenance plans, and SIP 

submittals from states and noted that because the court directed EPA to continue administering 

CAIR pending the promulgation of a valid replacement: 

 ...we believe that it will be appropriate to rely on CAIR emission reductions as 

permanent and enforceable for certain actions in certain circumstances. Specifically, we 

believe it will be appropriate to rely on those reductions until the petition and any further 

proceedings in the CSAPR case are resolved or, if the decision vacating CSAPR is not 

changed, until a valid replacement rule is developed and implementation plans 

complying with any new rule are submitted by the states and acted upon by the EPA. 

Thus, action on the pending requests and SIPs may go forward. 

It is noted, that EPA has appealed the DC Circuit Court’s decision to vacate CSAPR to the 

Supreme Court, and the Supreme Court has agreed to hear the case. As a result of this continued 

litigation, there is still uncertainty regarding CSAPR.

However, the CAIR requirements for ozone season NOx emission reductions remain in effect and 

this CAIR emission trading program is operating. Moreover, the D.C. Circuit has ordered EPA 

to continue implementing CAIR pending development of a replacement rule. Therefore, CAIR 

may be relied upon as the permanent and enforceable control measures to control ozone season 
33 

NOx emissions from EGUs that are included in this program until an equivalent or better rule / 

program is in place. 

4.2.2 Federal Mobile Source Emission Controls 

Federal and state regulations for mobile sources that have been phased in since 2002 have had a 

positive impact on the emissions inventory for both NOx and VOC emissions from on-road and 

non-road mobile sources. Mobile source regulations including Heavy-Duty Diesel Engine 

Standards and Low-Sulfur Diesel, Tier 2 Rule-Vehicle Standards, Tier 4 Rule-Off Road Mobile 

Engine Standards, Reformulated Gasoline (RFG), and the Gateway Vehicle Inspection Program 

(10 CSR 10-5.381 On-Board Diagnostics Motor Vehicle Emissions Inspection.) have reduced the 

NOx and VOC emissions from the mobile sector in the St. Louis nonattainment area. 

Overall, the retirement of older higher polluting vehicles and the phasing in of federal on-road 

mobile source standards from 2002 to 2008 have contributed to a decrease of 62.8 tons/ozone 

season day of direct NOx emissions (about 40% reduction), and 10.2 tons/ozone season day of 

VOC emissions (about 15% reduction). These on-road mobile source emission reductions have 

significantly contributed to attainment of the 1997 8-hour ozone NAAQS in the St. Louis area. 

Federal regulations for the control of mobile sources are permanent and enforceable, and it is 

likely that standards will become increasingly more stringent for the mobile source sector. The 

mobile source control measures have resulted in the significant reductions in both NOx and VOC 

emissions. The continued tightening of federal mobile source standards and phase out of older 

higher-polluting vehicles will continue to contribute to maintenance of the 1997 8-hour ozone 

NAAQS. 

4.2.3 State Regulations 

In addition to the Gateway Vehicle Inspection Program, federal mobile source standards, and the 

state regulations written to control ozone season NOx emissions in response to the NOx SIP Call, 

there are numerous state regulations that provide permanent and enforceable controls for NOx

and VOC emissions in the St. Louis nonattainment area. The rules in Title 10 Division 10 

Chapters 5 and 6 of the Missouri Code of State Regulations include permanent and enforceable 

control measures for ozone precursor emissions in the St. Louis nonattainment area. These 

controls include control technique guidelines for numerous VOC sources, open burning 

restrictions, and emission standards for incinerators. For additional information on state 

regulations to control VOC emissions in the St. Louis area, see the 2011 Reasonably Available 

Control Technology Demonstration Update for the 1997 8-Hour Ozone Standard in the St. Louis 

Area discussed in section 4.3 below. 

Furthermore, many regulations designed for one pollutant control program have a benefit in 

another. For example, the rules which implement the Air Toxics or Hazardous Air Pollutants 

(HAPs) program pursuant to CAA Section 112 also in many cases control VOCs. In Missouri, 

this program is implemented through State rules, 10 CSR 10-6.070 New Source Performance 

Regulations, 10 CSR 10-6.075 Maximum Achievable Control Technology Regulations & 10 CSR 

10-6.080 Emission Standards for Hazardous Air Pollutants. Although these rules are ostensibly 

for the control of HAPs, they benefit ozone control (and as such are listed in section 4.2) because 

many HAPs are also VOCs. 
34 

4.3 Reasonably Available Control Technology (RACT) 

Pursuant to Sections 172, 182(b) and (f) of the CAA, RACT is required for all existing major 

sources of the applicable criteria pollutant and its precursors located in nonattainment areas. The 

EPA defines RACT as the lowest emissions limitation that a particular source is capable of 

meeting by the application of control technology that is reasonably available considering 

technological feasibility and economic reasonableness [70 FR 71612; November 29, 2005]. The 

major source threshold for moderate nonattainment areas is defined as 100 tons per year (tpy) of 

NOx or VOCs. A source generally consists of several units that emit pollutants. The sum of 

emissions from all units at the source determines if a unit is major and thus subject to RACT 

requirements. 

On April 20, 2011, the Air Program requested an exemption for sources of nitrogen oxides (NOx) 

in the Missouri portion of the St. Louis metropolitan 8-hour ozone nonattainment area from the 

NOx RACT obligations pursuant to CAA Section 182(f). The waiver demonstrates that 

additional reductions of NOx emissions in the area would not contribute to attainment of the 

1997 ozone NAAQS. EPA published this exemption as a direct final rule and received no 

comments on this rule [76 FR 43598]. The rule became effective September 19, 2011. This NOx

waiver alleviates the requirements for a demonstration that NOx RACT obligations have been 

met. Therefore, only VOC RACT demonstration requirements are necessary for redesignation. 

 

Sections 172, 182(b)(2), and 182(f) of the CAA also require implementation of RACT for 

sources that are subject to Control Techniques Guidelines (CTGs) documents that are 

promulgated by the EPA. The EPA has issued CTGs defining presumptive RACT for those 

categories of sources that emit the greatest amounts of VOC emissions. In 2006-2008, the EPA 

issued 12 new CTG’s in three groups. The 2006 CTG’s addressed industrial cleaning solvents, 

offset lithographic printing and letterpress printing, flexible package printing and flat wood 

paneling coatings. The 2007 CTG’s address paper, film, and foil coatings, large appliance 

coatings, and metal furniture coatings. The 2008 CTG’s address miscellaneous metal and plastic 

parts coatings, fiberglass boat manufacturing materials, miscellaneous industrial adhesives, and 

automobile and light-duty truck assembly coatings. Per the CAA, CTG’s establish presumptive 

RACT for the VOC sources they cover. CTG RACT can apply to sources at a level much lower 

than the 100 tpy threshold employed for other RACT sources in moderate ozone nonattainment 

areas. In fact, some of these newly-issued CTGs apply to sources with emissions as low as 2.5 

tpy. Any state with moderate ozone nonattainment areas must implement equivalent RACT for 

all promulgated CTGs prior to redesignation of those areas. The Air Program developed 

amendments to four VOC rules to address these new CTGs for which there are existing 

applicable sources in the St. Louis nonattainment area. 

The (4) four rules that have been amended to account for these new CTGs are — 

 10 CSR 10-5.330 Control of Emissions From Industrial Surface Coating Operations

 10 CSR 10-5.340 Control of Emissions From Rotogravure and Flexographic Printing

 10 CSR 10-5.442 Control of Emissions from Lithographic Printing Operations

 10 CSR 10-5.455 Control of Emissions from Solvent Cleanup Operations
35 

These new rulemakings were proposed for public hearing March 31, 2011, and were adopted by 

the MACC on April 28, 2011. The first three rules listed above were approved by EPA on 

January 23, 2012 [77 FR 3146] for inclusion into the SIP. The fourth rule, 10 CSR 10-5.455, 

underwent another minor revision in 2012 and also became SIP-approved by EPA on January 6, 

2014 [79 FR 580]. The approval of these CTG rules was a necessary element to allow the St. 

Louis area to be redesignated to attainment for the 1997 ozone standard. 

RACT is not a new requirement for the 1997 8-hour ozone NAAQS. Missouri has previously 

addressed RACT requirements in the St. Louis nonattainment area in developing attainment 

plans for the 1-hour ozone standard. For the 1997 8-hour standard, the Air Program developed a 

RACT demonstration as an element to the ozone SIP revision. Per the federal implementation 

rule for the 1997 ozone standard, the RACT demonstration was to be submitted as a separate 

element prior to the submittal of the attainment demo and other elements of the SIP revision. 

RACT plan was adopted on December 7, 2006 and submitted to the EPA on January 5, 2007. 

Since these new CTGs were not considered in the 2006 RACT demonstration, and in an effort to 

ensure that RACT determinations for the St. Louis nonattainment area are ongoing and 

continuous, the Air Program developed an update to the 2006 RACT demonstration to support 

this redesignation request. Because of the NOx RACT waiver, this updated RACT 

demonstration showed how VOC RACT has been upgraded as appropriate since the last RACT 

submittal. This updated VOC RACT document was adopted by the MACC on April 28, 2011 

and submitted to EPA on May 25, 2011. The document was conditionally approved by EPA on 

January 23, 2012 and finally approved into the SIP on January 6, 2014 [79 FR 580]. 

For a more detailed discussion of RACT issues, please refer to the updated RACT demonstration 

adopted April 28, 2011, which can be found at http://dnr.mo.gov/env/apcp/sips.htm#ozone 

 
36 

5. Maintenance Plan Demonstration: Emission Inventory and 

Controls from 2008 - 2025 

The purpose of this chapter is to address the first two elements required for a maintenance plan 

as listed in subsection 2.4 of this document, which include providing a comprehensive attainment 

year emissions inventory and a projected emissions inventory at least ten years into the future 

after the SIP is approved. This section demonstrates that emissions of NOx and VOC in the 

Missouri portion of the St. Louis nonattainment area will remain below the levels of the 

attainment year emissions inventory, based on permanent and enforceable emission control 

requirements, for a period of ten years after EPA approves this maintenance plan. This section 

also includes an emissions inventory for an interim year to demonstrate that emissions in the St. 

Louis area will remain below the attainment year emissions inventory throughout the ten-year 

maintenance period. 

The future year of 2025 was used in this maintenance plan because the future year included in a 

maintenance plan must be at least 10 years into the future after EPA approves the plan. By 

selecting 2025 for the future year EPA will have more than a year to approve this plan and 

redesignate the area to attainment. 

This chapter also includes a discussion of regulations that have become effective since 2008, and 

a list of expected future regulations that will help to continue to control NOx and VOC emissions 

in the St. Louis area. The Air Program commits to keeping all previously adopted control 

measures that are included in Missouri’s approved SIP in place after redesignation unless the SIP 

is revised and approved by EPA to remove such requirements. If the removal of such 

requirements would potentially alleviate control requirements for emission sources in Missouri, 

then the SIP revision shall require an “anti-backsliding” demonstration under Section 110(l) of 

the Clean Air Act. In addition, nonattainment new source review (NSR) permitting requirements 

will continue to apply to construction of new major sources and to significant modifications of 

existing sources due to the area’s designation as nonattainment under the more recently 

promulgated 2008 ozone NAAQS. These existing and future control measures identified in the 

maintenance plan are relied upon to maintain the 1997 8-hour ozone NAAQS. 

5.1 Base/Attainment Year Inventory and Future Year Emission Projections 

A maintenance plan must contain a demonstration that the levels of emissions projected for the 

ten-year period following redesignation are sufficient to maintain the NAAQS. Accordingly, the 

Air Program has projected NOx and VOC emissions for the St. Louis nonattainment area for 

2025. Emissions for this projection year are compared to emissions levels in 2008 to determine 

if emissions levels are sufficient to maintain the NAAQS during this period. 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]. Therefore, this section 

only includes emissions inventories and projections for the Missouri portion of the nonattainment 

area. The emissions inventories for the years 2008, 2015, 2020, and 2025 for the Illinois portion 

of the nonattainment area, which were included in Illinois’ approved maintenance plan, are 

provided for reference in Appendix H. 
37 

For the purposes of this section, a modified 2008 emission inventory was developed. The 2008 

inventory in this section will act as the base year compared to the 2025 inventory detailed in this 

section. The base year 2008 inventory includes point, area, on-road mobile, and non-road source 

categories. The emissions from point, area, and non-road source categories are identical to the 

2008 attainment year inventory listed in the previous chapter. However, the on-road mobile 

source inventory is different. This is due to the fact that a different mobile emission model was 

used to develop the inventory in this section of the document, which is explained in further detail 

below in paragraph 5.1.1. The 2008 base year annual emissions inventory for the Missouri side 

of the nonattainment area is included in this plan as Appendix B. 

5.1.1 On-Road Mobile Source Emissions Inventory Development 

For this section of the document, on-road motor vehicle emissions for the Missouri side of the 

nonattainment area were developed using U.S. EPA’s MOVES motor vehicle emissions model 

and VMT data from East-West Gateway Council of Government in coordination with the St. 

Louis Transportation Conformity Interagency Consultation Group. 

The method for mobile emissions modeling was changed when EPA’s previous on-road mobile 

model (Mobile 6) was replaced with a completely redesigned model (MOVES). The MOVES 

model was redesigned to reflect EPA’s current understanding of the emissions produced by 

vehicles and the various factors that affect these emissions. 

As a result of these changes to the model, MOVES produced higher emissions estimates for both 

2008 and 2025 than were originally created with Mobile 6.2 via NMIM (refer to section 4.1). 

NOx emissions increased for the extended idling of heavy duty vehicles. VOC emissions 

calculated with MOVES are comparable to VOC emissions calculated with Mobile 6.2, however 

they are slightly higher. Therefore, in addition to running a projected emissions budget for 2025 

for on-road emissions, 2008 base year emissions were also run using MOVES for the Missouri 

portion of the nonattainment area. This allows for a meaningful comparison in emissions from 

2008 to 2025. By using MOVES to calculate the 2008 and 2025 mobile emission inventories, a 

smooth transition will occur for any new mobile modeling that will be needed in future SIP 

revisions. 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. 

5.1.2 Point, Area, and Off-Road Mobile Source Emissions Inventory Development 

for the Missouri Side of the Nonattainment Area 

The projected point and 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/ttnecas1/egas5.htm) using economic growth projections from the Policy 

Insight® Model for Regional Economic Model, Inc (REMI). Area source stage II refueling 

emissions for 2025 were calculated with MOVES and assumed that Stage II vehicle refueling 

vapor recovery controls would no longer be required in the St. Louis area by 2025. The Air 

Program is currently developing a SIP revision to remove Stage II requirements as a result of the 

widespread use of on-board vapor recovery systems, and it is expected that Stage II controls on 
38 

refueling stations in the Missouri portion of the St. Louis nonattainment area will be completely 

removed by December 31, 2015. 

An adjustment was made to account for the retirement of two units located at MEMC Electronic 

Materials, Inc. that were subject to a 2009 Consent Agreement. These two emission units will no 

longer be permitted to operate unless a new construction permit is granted, therefore, the consent 

agreement was terminated in 2013. A copy of the 2009 consent agreement and the letter from 

the Air Program terminating the agreement is included in this document as Appendix G. 

Finally, ozone season NOx emissions from EGUs in the future year were projected based on 

permanent and enforceable controls in place for these sources. The ozone season NOx emissions 

from the following four EGU facilities: Ameren’s Labadie, Meramec, Rush Island, and Sioux 

were grown as follows: 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 of NOx emissions over 

these four years. This yearly regulatory ozone season average of NOx 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. 

NOx and VOC emissions from non-road sources for 2008 and 2025 for the Missouri side of the 

nonattainment area were developed using the U.S. EPA’s NONROAD model. The non-road 

source emissions inventory also includes emissions from aircraft takeoffs and landings, 

commercial marine vessels, and locomotives. The emissions from these three categories were 

grown from 2008 levels to the future year using EGAS growth factors. 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. 

5.1.3 2008 and 2025 Emissions Inventory Summary for the Missouri Side of the 

Nonattainment Area 

Table 5-1 displays the 2008 ozone season day emissions inventory summary for the Missouri 

portion of the nonattainment area for point, area, on-road mobile, and non-road source 

categories. Table 5-2 displays the projected emissions inventory summary for the future year in 

this plan (2025) for the Missouri portion of the nonattainment area. 

Table 5-3 provides a comparison of emissions for the years 2008 and 2025, using the 2008 onroad mobile source emissions listed in Table 5-1 to reflect the MOVES values for consistent 

comparison purposes. Table 5-3 shows the differences by source category along with the total 

changes in emissions for each pollutant listed. As shown in the table, both NOx and VOC 

emissions within the nonattainment area are expected to decrease significantly between 2008 and 

2025. NOx emissions are expected to drop nearly 47%, while VOC reductions are about 6.5% 
39 

over the projected period. Based on these emissions trends for NOx and VOC it is expected that 

air quality will continue to meet the 1997 8-hour ozone NAAQS throughout the maintenance 

period. 

Table 5-1. 2008 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Source Category NOx VOC 

Point Sources 88.84 18.0 

Area Sources 6.52 98.74 

On-Road Mobile Sources 160.38 58.53 

Off-Road Mobile Sources 60.85 46.44 

Total 316.59 221.71 

Table 5-2. 2025 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Source Category NOx VOC 

Point Sources 89.81 28.01 

Area Sources 6.85 130.91 

On-Road Mobile Sources 41.66 20.15 

Off-Road Mobile Sources 29.44 28.17 

Total 167.76 207.24 

Table 5-3. Comparison of 2008 and 2025 VOC and NOx Emissions for the Missouri 

Side of the 1997 St. Louis 8-Hour Ozone Nonattainment Area (tons per ozone season 

day) 

Source Category NOx VOC 

Point Sources* +0.97 +10.01 

Area Sources* +0.33 +31.44 

On-Road Mobile Sources* -119.59 -40.71 

Off-Road Mobile Sources* -24.17 -16.99 

Total* -148.83 -14.47 

*Note: A negative value indicates a projected decrease in emissions from 2008 to 2025. 

A positive value indicates a projected increase in emissions from 2008 to 2025.

It should be noted that the projected increase in VOC emissions for point and area sources are 

based on (EGAS) growth factors. Due to the use of these growth factors, emissions of VOC 

from point and area sources are projected to increase by 2025. However, these projected 

increases are likely overstated and actual point and area source emissions of VOC are not 

expected to increase as much as the growth factors suggest. EPA’s Regulatory Impact Analysis 

(RIA) for the 2006 PM NAAQS rule, Appendix D 

(http://www.epa.gov/ttn/ecas/regdata/RIAs/Appendix%20D--Inventory.pdf), notes on pages D29 to D-36, that though REMI data was used in their emission forecasting method, the 
40 

oversimplification of emissions growth based on economic factors likely overestimates projected 

emissions. EPA’s recognition of the downward trend in emissions during times of economic 

growth supports the conclusion that the VOC increases for area sources are likely an artifact of 

the growth methodology. From page D-36 — 

While it is not clear that all of the factors that have served to produce this historical 

decline will continue to operate in the future, it appears unreasonable to assume that we 

currently have arrived at an ‘inflection point’ past which the trend will stop or reverse 

itself. Indeed, because the available data show that a number of large sources in the 

sectors of interest have no or limited pollution controls, it is reasonable to expect 

emissions rates will be steady or decline. Continuing to ignore this factor in future-year 

emission projections may increasingly skew the predicted emissions increase, and the 

farther into the future the forecast the more dramatic the impact. The preceding and 

other explanations suggested that we need to reevaluate our emission forecasting 

approaches for stationary non-EGU sources to incorporate factors not adequately 

considered in past methodologies.

Despite these conservative projections from EGAS growth factors, NOx and VOC emissions are 

still projected to decrease on the Missouri side of the nonattainment area from 2008 – 2025, 

when looking at all source categories combined. The projected decrease from each pollutant on 

the Missouri side of the nonattainment area from 2008 to 2025 is due to permanent and 

enforceable control requirements. 

The projected decreases in NOx and VOC emissions from 2008 to 2025 are primarily due to 

decreases in the on-road mobile and non-road source categories. Average ozone season daily 

NOx and VOC emissions in the St. Louis area from these two categories are projected to 

decrease by approximately 144 tons/day and 58 tons/day, respectively. That amounts to an over 

40% reduction of total NOx emissions in the area and an over 25% reduction of total VOC 

emissions in the area compared to emissions levels in 2008 from on-road mobile and non-road 

sources. 

The maintenance demonstration is based on the comparison of the actual emission levels in 2008 

and the projection of emissions in the future year of the plan. Because the area attained the 

standard in 2008, this is expected to be a level of emissions suitable to maintain the level of the 

standard. Because aggregate emissions in both pollutant categories in 2025 are expected to be 

less than 2008 actual levels, this satisfies the maintenance demonstration under the 1997 ozone 

NAAQS for the Missouri portion of the nonattainment area. 

As mentioned above, additional details about the 2008 and 2025 emission inventories can be 

found in Appendices B and D, respectively. It should also be noted that the emissions 

projections included here do not reflect the reductions expected from a range of measures being 

implemented to reduce diesel emissions in the St. Louis nonattainment area. These measures 

include — 

 U.S. EPA’s Midwest Clean Diesel Initiative 

 Congestion Mitigation and Air Quality Improvement (CMAQ) Program 
41 

 Diesel Emissions Reduction Act (DERA) grant projects 

 American Recovery and Reinvestment Act of 2009 (ARRA) grant projects 

 Heavy Duty Diesel Idling Rule, 10 CSR 10-5.385

 Various supplemental environmental projects. 

These projects include the installation of particulate filters, diesel oxidation catalysts, closedcrankcase ventilation systems, and direct-fired heaters on school and transit buses, and 

municipally-owned utility vehicles, upgrading diesel construction engines with engines meeting 

more stringent emissions standards, and installing auxiliary power units on over-the-road trucks 

to reduce idling. It is anticipated that DERA and CMAQ funding will continue to support 

additional diesel emissions reduction projects in the near future. 

5.2 Interim Year Emission Inventory: 2017 

The Air Program has developed an Interim Emission inventory for the Missouri portion of the St. 

Louis nonattainment area. Interim year 2017 is the midway point between 2008, the base year of 

the maintenance plan, and 2025, the last year in the ten year maintenance plan period. An 

analysis of an interim year emissions inventory is necessary to demonstrate that future emission 

levels will remain below the attainment year emission levels throughout the entire 10-year 

maintenance period. This provides assurance that air quality in the St. Louis area will continue 

to comply with 1997 ozone NAAQS for the duration of the maintenance period addressed in this 

plan. 

All assumptions and controls used in developing the projected 2025 emission inventory in 

section 5.1 of this document were also used to project the 2017 inventory. Table 5.4 summarizes 

the emissions for point, area, on-road mobile, and non-road sources that are projected for 2017 

for the Missouri portion of the St. Louis nonattainment area. From 2008 to 2017, NOx emissions 

drop by 125.1 tons/day, a reduction of about 40%, while VOC emissions drop by 26.65 tons/day 

or about 12%. As seen in Table 5-4, the interim year emissions levels in the area will remain 

below the 2008 base year for both pollutant categories, thus demonstrating that the area will 

continue to maintain the standard throughout the 10-year maintenance period. The Air Program 

commits to analyzing actual 2017 emissions for the Missouri side of the St. Louis nonattainment 

area and comparing the actual 2017 emissions to the projected 2017 emissions listed in Table 5.4 

to ensure the area keeps pace with the reductions expected throughout the maintenance period. 

Additional details about the development of the 2017 interim year emission inventory for the 

Missouri side of the nonattainment area can be found in Appendix C of this document. 

Table 5-4. 2017 VOC and NOx Emissions for the Missouri Side of the 1997 St. Louis 

8-Hour Ozone Nonattainment Area (tons per ozone season day) 

Source Category NOX VOC 

Point Sources 87.01 22.82 

Area Sources 6.68 115.85 

On-Road Mobile Sources 62.32 27.51 

Off-Road Mobile Sources 35.53 28.88 

Total 191.54 195.06 
42 

5.3 Future Federal Control Measures 

There are currently several federal control measures that have recently been proposed or 

promulgated that are expected to greatly reduce the amount of NOx and VOC emissions in the St. 

Louis area. The control measures expected to have the greatest effect on NOx and VOC 

emissions in the St. Louis area include the federal CAIR phase II and/or its future replacement, 

the Mercury and Air Toxics Standards for Fossil-Fuel Fired Electric Utility Steam Generating 

Units (MATS), National Emission Standards for Hazardous Air Pollutants for Major Sources: 

Industrial, Commercial, and Institutional Boilers and Process Heaters (Boiler MACT), improved 

motor vehicle fuel efficiency standards, the phase in of tier 4 emission standards for non-road 

engines 

CAIR phase II and the improved federal mobile source regulations were both considered when 

developing the future emissions inventory in order to demonstrate continued maintenance with 

the 1997 8-hour ozone standard, which shows that projected future year NOx and VOC emissions 

in the St. Louis area will remain below the levels experienced during the attainment year. Under 

CAIR phase II, which begins in 2015, ozone season NOx emissions budgets for EGUs decrease 

by 17% for covered sources in the Missouri portion of the nonattainment area. As stated earlier, 

federal motor vehicle and non-road engine standards are only expected to be tightened in the 

future, which will also contribute to NOx and VOC emission reductions. These recent and 

anticipated future federal control measures are expected to result in continued decreases in NOx

and VOC emissions both nationwide and in the St. Louis area. These measures will greatly 

assist current and ongoing efforts in the St. Louis area to maintain compliance with the 1997 8-

hour ozone NAAQS. 

The MATS and the Boiler MACT were both written to address hazardous air pollutants, and will 

therefore have the greatest reductions in pollutants such as PM2.5 and SO2. However, if owners 

of boilers and EGUs subject to these new rules decide to improve plant efficiency or switch to 

cleaner fuels for compliance strategies, then there is expected to be co-benefits for NOx and VOC 

emissions from these sources. The Air program did not rely on the Utility MACT or the Boiler 

MACT when developing the future year emissions inventory or to determine that the St. Louis 

area would remain in attainment of the 1997 8-hour ozone NAAQS. However, the anticipated 

reductions from these new rules may also contribute to the future attainment of the 1997 8-hour 

ozone NAAQS in the St. Louis area. 

5.4 New Source Review: Permitting New or Modified Emissions Sources 

In accordance with the Clean Air Act, Missouri has a long-standing and fully implemented New 

Source Review (NSR) permitting program for new major sources and significant modifications 

of existing sources enabled by State rule 10 CSR 10-6.060 Construction Permits Required. This 

NSR program in any attainment area is referred to as a Prevention of Significant Deterioration 

(PSD) permitting program. One of the major components of the PSD program is the 

implementation of Best Available Control Technology (BACT) on new major sources or 

significant modification of existing major sources. Missouri has been delegated full authority to 

implement the PSD program by the EPA. 

In this document, the Air Program is requesting redesignation to attainment under the 1997 8-

hour ozone standard. However, the St. Louis nonattainment area has already been designated as 
43 

nonattainment under the 2008 ozone NAAQS. Therefore, the State of Missouri is fully 

committed to continuing its NSR permitting program for nonattainment areas which makes new 

major sources and significant modifications of existing sources subject to the Lowest Achievable 

Emission Rate (LAER) as well as offsets and an alternate site analysis pursuant to the CAA. 

State rule 10 CSR 10-6.410 Emissions Banking and Trading, allows the banking and trading of 

emission reduction credits to be used for permitting purposes. These emission reduction credits 

are reduced by 25 percent at the time they are banked and they are further reduced by 3 percent 

every year they remain banked. These credits are intended to be used for NSR offset purposes in 

nonattainment areas and for PSD increment purposes in areas designated attainment. However, 

these credits are only one aspect of obtaining a permit under Missouri’s EPA approved Title V 

permitting program, and do not alleviate any source from undergoing a NAAQS impact analysis 

in any area. Nor do these credits alleviate any source from implementing BACT requirements 

for PSD permits in attainment areas or LAER/alternative site analysis requirements in 

nonattainment areas. Therefore, the emission reduction credits that have been banked by 

Missouri sources are not anticipated to have any impact on Missouri’s demonstration that the St. 

Louis area will continue to maintain the 1997 ozone NAAQS in the St. Louis area. 

Therefore, Missouri has satisfied the requirements of both CAA Sections 110(a)(2)(C) & 

172(c)(5) (which in turn satisfies a redesignation element of Section 107(d)(3)(E)(v)) for the 

1997 ozone NAAQS through its approved NSR program. 

5.5 Update: Recent Emission Reductions 2012 - 

Monitored ozone air quality concentrations in the St. Louis area for the most recent three-year 

period of 2011-2013 complied with the 1997 NAAQS despite 2012 being among the hottest, 

most ozone-conducive years on record. This maintenance plan demonstrates that the downward 

trend in ozone concentrations is due to permanent and enforceable emission controls. This 

section addresses additional emission reductions of ozone precursors that have occurred since 

2012 to support this downward trend. 

5.5.1 Stationary Source Ozone Season NOx Emission Reductions from EGUs 

Based on a review of continuous emissions monitoring systems (CEMS) data reported to the 

EPA’s Clean Air Market Division, the four Ameren EGU facilities have reduced regulatory 

ozone season (May–September) NOx emissions by 248 tons between 2012 and 2013. These 

emission reductions are despite the fact that these units produced an additional 283,000 

Megawatt-hours of electricity in 2013 compared to 2012, meaning that these reductions were not 

due to a reduction in electricity production or demand but rather an improvement in average 

emission rates that have resulted from the continued optimization of the emission controls at 

these facilities. 

Looking at the full eastern third of the state, which contributes to ozone concentrations in the St. 

Louis nonattainment area, regulatory ozone season NOx emissions from EGUs decreased by a 

total of 2,226 tons between 2012 and 2013. In 2013, electricity production from the EGUs 

located in the eastern third of the state was down 2% compared to 2012; however, the ozone 

season NOx emissions reductions achieved by these EGUs between 2012 and 2013 account for 
44 

an 11% reduction, meaning that emission rates have improved at these facilities between these 

two years. 

In 2015, CAIR phase II will begin, which will reduce NOx allowances by 17% for EGUs in 

Missouri. This is only expected to result in continued ozone season NOx emission reductions 

from EGUs in the states subject CAIR including the EGUs located in and in close proximity to 

the nonattainment area. These allowance reductions also act as a margin of safety since the 

projected emission inventories for 2017 and 2025 used in this plan to demonstrate maintenance 

of the 1997 standard did not account for this reduction but rather assumed a steady level of 

emissions from these sources. 

5.5.2 On-Road Mobile Source Emission Reductions 

Due to federal motor vehicle standards and the retirement/replacement of older higher polluting 

engines, on-road mobile source emissions of NOx and VOC continue to decline each year in and 

around the St. Louis nonattainment area. EPA’s MOVES model was used to calculate the onroad mobile source NOx and VOC emissions in the last two years. Between 2012 and 2013, onroad mobile source NOx and VOC emissions inside the Missouri portion of the nonattainment 

declined by approximately 265 tons/ozone season and 407 tons/ozone season (April – October), 

respectively. On-road mobile source emission reductions are expected to continue in the 

nonattainment area as additional older vehicles are retired and replaced by new vehicles meeting 

the latest federal motor vehicle standards. 

On March 3, 2014 the EPA administrator signed the final rule for Tier III motor vehicle engine 

standards, which will begin in 2017. EPA states in the final ruleFor many pollutants, the immediate reductions in 2018 are significant; for example, 

combined NOX and VOC emissions will be reduced by over 300,000 tons. By 2030, combined 

NOX and VOC emissions will be reduced by roughly 500,000 tons, one quarter of the onroad 

inventory. 

The Tier III standards were not relied upon in the maintenance demonstration included with this 

plan, but the new standards will provide additional assurance that ozone precursor emissions 

continue to decline in the MO-St. Louis nonattainment area and throughout the entire country as 

a result of permanent and enforceable on-road mobile source control measures. 

5.5.3 Diesel Emissions Reduction Act Projects 

The Missouri Department of Natural Resources has implemented numerous grant projects under 

the Diesel Emissions Reduction Act (DERA) since 2008. These projects have resulted in the 

reduction of NOX, PM, VOC, CO, and CO2 emissions from diesel engines that operate in 

Missouri. Many of the projects have targeted diesel fleets that operate in and around the St. 

Louis nonattainment area including school buses, construction equipment, refuse haulers, street 

sweepers, long-haul trucks, locomotives, and tugboats. 

Below is a list of DERA projects that have been implemented by the Air Program in the St. 

Louis area since 2012: 
45 

1. Massman Construction: Engine repowers for two 230 horsepower propulsion engines on 

a tugboat operating almost exclusively inside the nonattainment area. The repower 

project replaced unregulated tier 0 engines with engines meeting tier 2 emission 

standards. The tier 0 engines were disabled ensuring the permanence of the emissions 

reductions. 

2. Pullen Enterprise: Early replacement for a long-haul class 8 truck that operates almost 

exclusively in Missouri with approximately 50% of its operations inside the 

nonattainment area. The project replaced a 2000 model year truck with a 2013 model 

year truck that is certified at approximately 90% lower NOX and PM emissions standards 

that the truck that was replaced. The old truck’s engine and chassis were disabled 

ensuring the permanence of the emissions reductions. 

3. DeSoto School District: Idle reduction and tailpipe emission control retrofits for 23 buses 

operated by the school district. All of these buses operate almost exclusively inside the 

nonattainment area. 

4. ADM Grain: Engine repower for a 1200 horsepower engine for a switch locomotive 

stationed in the City of St. Louis that operates almost exclusively inside the 

nonattainment area. The repower project replaced an unregulated tier 0 engine with a 

new engine meeting tier 3 emission standards. The old engine was disabled ensuring the 

permanence of the emissions reductions. 

5. JB Marine: Engine repowers for four propulsion engines on two different tugboats 

operating almost exclusively inside the nonattainment area. Two engines were 285 

horsepower and the other two were 300 horsepower. All four engines that were replaced 

were unregulated tier 0 engines, and each was replaced by new engines meeting tier 2 

emissions standards. All four of the tier 0 engines were disabled ensuring the 

permanence of the emissions reductions. 

These permanent voluntary emissions reductions, although not relied upon in this plan to attain 

the NAAQS or to demonstrate maintenance of the NAAQS, provide additional emissions 

reductions that have occurred in the St. Louis area in the recent past, which have contributed to 

improved ozone concentrations in the area. 

 
46 

6. Transportation Conformity 

Transportation conformity is required under CAA Section 176(c) (42 U.S.C. 7506(c)) to ensure 

that transportation plans, transportation improvement programs and federally supported highway 

transit project activities are consistent with (“conform to”) the purpose of the SIP. Conform to 

the purpose of the SIP means that transportation activities will not cause new air quality 

violations, worsen existing violations, or delay timely attainment of the relevant NAAQS or any 

interim milestones. These requirements are found in CAA Section 176(c)(B)(i), (ii), and (iii): 

That such activities will not cause or contribute to any new violation of any standard in 

any area; increase the frequency or severity of any existing violation of any standard in 

any area; or delay timely attainment of any standard or any required interim emissions 

reductions or other milestones in any area. 

Transportation conformity applies only to those areas that are designated nonattainment, and 

those areas redesignated to attainment after 1990 (“maintenance areas”) for transportation-related 

criteria pollutants: Carbon monoxide (CO), ozone, nitrogen dioxide (NO2) and particulate matter 

(PM2.5 and PM10). The Transportation Conformity program for the St. Louis area is included in 

the SIP via State rule 10 CSR 10-5.480 St. Louis Area Transportation Conformity Requirements. 

The establishment of MVEBs for transportation conformity purposes is one of the redesignation 

elements of CAA Section 175A as mentioned in section 2.4 of this document. EPA’s final rule 

for establishing ozone area classification thresholds under the 2008 ozone NAAQS revoked the 

1997 ozone NAAQS for transportation conformity purposes [77 FR 30160]. This revocation is 

effective one year after the effective date of designations for the 2008 ozone NAAQS (July 20, 

2013). Therefore, transportation conformity (and the corresponding establishment of MEVBs) 

for the 1997 ozone NAAQS is no longer required. This revocation date also corresponds with 

the end of the one-year conformity grace period for the 2008 ozone NAAQS. This action was 

taken by EPA to bring certainty to the transportation planning process in ozone nonattainment 

and maintenance areas. EPA stated that no backsliding will result from the revocation for 

purposes of transportation conformity, and areas designated nonattainment for the 2008 ozone 

NAAQS will be required to use any existing adequate or approved SIP MVEBs for a prior ozone 

NAAQS when determining conformity for the 2008 ozone NAAQS until budgets for the 2008 

ozone NAAQS are either found adequate or are approved. Therefore because of the revocation, 

this maintenance plan does not establish MVEBs for the 1997 ozone NAAQS. 

As mentioned above, transportation conformity for the 2008 ozone NAAQS applies one year 

after the effective date of nonattainment designations for this NAAQS, i.e., July 20, 2013. As a 

result, on January 30, 2013, East-West Gateway Council of Governments, the designated 

Metropolitan Planning Organization for the greater St. Louis area, approved a Transportation 

Conformity Determination addressing the 2008 NAAQS : 

http://www.ewgateway.org/pdffiles/library/AQ/AQConformityDoc/AQConformityDocFY2013.pdf . 

Although not a requirement for this redesignation under the 1997 standard, an Early Progress 

Plan establishing MVEBs for the 2008 standard has been separately developed by the Air 
47 

Program prior to our marginal-classified area plan obligations for the St. Louis area under this 

newer standard. This Early Progress Plan was adopted by the Missouri Air Conservation 

Commission on March 28, 2013. The Air program submitted the plan to EPA on August 16, 

2013 and EPA deemed the new budgets adequate in a letter dated October 28, 2013 just in time 

for the next conformity determination that began in the fall of 2013. More information on the 

MVEBs for the 2008 ozone NAAQS may be found in the Early Progress Plan at: 

http://www.dnr.mo.gov/env/apcp/docs/complete-epp-submittal-8-16-13.pdf. 
48 

7. Contingency Measures 

CAA Section 175(A) specifies the requirements for maintenance plans. In addition to providing 

a plan for the maintenance of the NAAQS for at least ten (10) years after the redesignation, the 

plan shall also include a list of contingency measures to correct any violation of the fine 

particulate matter NAAQS after redesignation to attainment. 

Contingency measures are to be used to further reduce emissions in the event that future 

violations of the 1997 8-hour ozone NAAQS occur after redesignation to attainment. While 

these measures do not need to be fully adopted by the Missouri Air Conservation Commission 

prior to the occurrence of a NAAQS violation, the contingency measures are expected to be 

implemented as expeditiously as possible once a triggering event occurs. The maintenance plan 

must identify the triggers that determine when contingency measures will be adopted, and the 

measures that the Air Program will consider. 

The Air Program has developed a contingency plan for the Missouri portion of the St. Louis 

ozone maintenance area. The contingency plan which details the Level I and Level II triggers 

and corresponding actions to be taken is summarized in Table 7-1. The potential contingency 

measures, to be evaluated after a triggering event, are listed in Table 7-2. Consistent with this 

contingency plan, the Air Program agrees to adopt and implement, as expeditiously as is 

practicable, the necessary corrective actions in the event that violations of the 1997 8-hour ozone 

NAAQS occur anywhere within the St. Louis ozone maintenance area after redesignation to 

attainment. The implementation of contingency measures under Level I or Level II triggers will 

take place as expeditiously as practicable, but in no event later than twenty-four (24) months 

after the Air Program makes a determination that a trigger has occurred, based on quality-assured 

ambient data that has been entered into EPA’s Air Quality System database. 

The contingency plan provides for different levels of corrective responses should the ambient 8-

hour ozone levels exceed the NAAQS in any year. A Level I response would occur in the event 

that the fourth highest 8-hour ozone concentration at any monitoring site in the St. Louis 

maintenance area (including sites in Missouri and Illinois) exceeds 84 ppb in any year. The Air 

Program will evaluate the air quality and determine if adverse emission trends are likely to 

continue. If so, the Air Program will determine what and where controls may be required, as 

well as the level of emissions reductions needed to avoid a violation of the NAAQS. If controls 

are required, the potential contingency measures listed in Table 7-2 will be evaluated in addition 

to other measures that may be identified through the evaluation or that become available through 

future advances in control technology and methods. It should be noted that the EPA does not 

require a state to implement contingency measures when occasional exceedances are recorded. 

The Air Program’s voluntary commitment to initiate a Level I response is intended to prevent 

future violations of the NAAQS from ever occurring. 

A Level II trigger occurs when a violation of the 1997 8-hour ozone NAAQS at any monitoring 

station in the St. Louis maintenance area is recorded after it has been redesignated to attainment. 

The Air Program will conduct a thorough analysis to determine appropriate measures to address 

the cause of the violation. Contingency measures will be selected from those listed in Table 7.2 

or from any other measured identified and deemed appropriate and effective at the time the 
49 

selection is made. Level II triggers are more serious than Level I triggers and cost effectiveness 

thresholds could be increased when determinations for additional controls are made. 

The contingency measures listed in Table 7.2 are expected to be evaluated in the event of a Level 

I or Level II trigger; however federal actions that require control measures may also be taken into 

account when the analysis to determine the cause of a future violation occurs. These additional 

federal actions, while not actual contingency measures, may be evaluated in the event of a trigger 

to determine their effect on the levels of expected emissions from sources in the area in order to 

determine whether or not additional local control measures are necessary. The measures that 

may be evaluated in the event of a future trigger include future federal on-road vehicle standards, 

future federal non-road engine standards for marine and locomotive engines, any future federal 

emission trading programs designed to address future ozone NAAQS promulgations, the 

Commercial-Industrial-Institutional Boiler Maximum Achievable Control Technology (MACT) 

requirements, and the Utility MATS requirements. Furthermore, the Air Program remains 

committed to addressing future ozone NAAQS revisions through state implementation plans. 

These plans could include other control techniques not included in Table 7.2. These and any 

other newly identified potential control measures may also be considered in the analysis 

following a future Level I or II triggering event. 

The Air Program commits to compiling NOx and VOC emissions inventories for the St. Louis 

maintenance area every three years for the duration of the Maintenance Plan to facilitate the 

emissions trends analysis included in the contingency plan under Levels I and II. Since St. Louis 

is a bi-state nonattainment area, the Air Program commits to work with Illinois EPA to evaluate 

emissions trends and the causes of Level I and Level II triggers to determine appropriate control 

measures needed to assure continued attainment of the 1997 8-hour ozone NAAQS. 

Adoption of additional control measures is subject to necessary administrative and legal 

processes. The Air Program will solicit input from all interested and affected persons in the area 

prior to selecting appropriate control measures. No contingency measures will be implemented 

without providing the opportunity for full public participation. This process will include 

publication of notices, an opportunity for public hearing, and other measures required by 

Missouri law. 

 
50 

Table 7-1. Contingency Plan for the Missouri Portion of the 1997 St. Louis 8-Hour 

Ozone Maintenance Area 

Contingency Measure 

Trigger Action to be Taken 

Level I Trigger 

Fourth highest monitored 

8-hour average ozone 

concentration exceeding 

84 ppb in any year at any 

monitoring station in the 

St. Louis, MO-IL 

maintenance area. 

The Air program will evaluate the air quality and determine if 

adverse emission trends are likely to continue. If so, the Air 

Program will determine what and where controls may be required, 

as well as the level of emissions reductions needed to avoid a 

violation of the NAAQS. The evaluation shall be completed as 

expeditiously as possible and, if necessary, control measures shall be 

adopted and implemented as expeditiously as practicable, taking into 

consideration the ease of implementation and the technical and 

economic feasibility of the selected measures. This action will be 

taken no later than 24 months after the Air Program has determined 

that a Level I trigger has occurred. 

Level II Trigger 

A monitored violation of 

the NAAQS at any 

monitoring station in the 

St. Louis, MO-IL 

maintenance area. 

The Air Program will conduct a thorough analysis to determine 

appropriate measures to address the cause of the violation. Analysis 

shall be completed within 6 months after the trigger occurs. 

Selected measures shall be implemented as expeditiously as 

practicable, taking into consideration the ease of implementation and 

the technical and economic feasibility of the selected measures. The 

appropriate contingency measures to address the violation shall be 

implemented as expeditiously as possible, but no later than 24 months after 

quality-assured ambient data that has been entered into EPA’s Air Quality 

System database indicating that this trigger has occurred.
51 

Table 7-2. Potential Contingency Measures for the Missouri Portion of the 1997 

St. Louis 8-Hour Ozone Maintenance Area 

List of Potential Contingency Measures to be Considered 

 Identify local sources with significant NOx and/or VOC emissions and develop controls through rules, 

NSR/PSD permits or consent agreements (e.g. For major NOx sources — boilers, cement kilns & 

incinerators); 

 Lower the applicability thresholds in existing rules that control NOx and VOC: 

o Some recent CTG RACT rules have reduced threshold for subject sources from 100 tpy to as 

low as 2.5 tpy. See section 4.3. 

o Examine other source categories for similar reductions and revise rules accordingly. 

 Lower the emission limits in existing rules: 

o Review current state of control technologies. Reference RACT/BACT/LAER Clearinghouse for 

new ideas. 

o Revisit RACT determination and update RACT plan accordingly. 

o Example: Lower the emissions from certain surface coating sources under 10 CSR 10-5.330 

Control of Emissions From Industrial Surface Coating Operations as lower VOC content / 

control technology improves. 

 New or strengthened Alternative Control Techniques (ACTs) for NOx sources & CTGs for VOC 

sources; 

 Develop rules to address contributing parts of Missouri outside of St. Louis nonattainment area; 

 Enhanced Heavy-Duty Diesel Anti-Idling Program (e.g. mandated rest periods and locomotives); 

 Update 10 CSR 10-6.130 Controlling Emissions During Episodes of High Air Pollution Potential:

o Lower the alert / action trigger levels. 

o Amend rule to require alert / action level abatement plans at more facilities. 

o Require existing abatement plans be amended with more current emission reduction measures 

(e.g. telecommuting at major facility would lower vehicle CO, VOC, NOx emissions) 

 Architectural/Industrial/Maintenance (AIM) Coatings similar to Ozone Transport Commission 

(OTC) model rule. 
52 

8. Conclusion 

The St. Louis nonattainment area has attained the 1997 0.080 ppm 8-hour ozone NAAQS and 

has complied with the applicable provisions of the CAA required of moderate ozone 

nonattainment areas. Missouri has supported, with appropriate submittals, including this one, all 

of EPA’s redesignation obligations under CAA Section 107 and has addressed all the applicable 

maintenance plan requirements of CAA Section 175A. This plan submission serves as the 

official redesignation request for the Missouri portion of the St. Louis moderate nonattainment 

area under the 1997 ozone NAAQS to be considered for approval concurrently with the 

maintenance plan also contained herein. 

The Missouri Department of Natural Resources’ Air Pollution Control Program has prepared this 

maintenance plan to provide for the continued attainment of the 1997 8-hour ozone NAAQS for 

a period of ten years after U.S. EPA has formally redesignated the area to attainment and also 

supplies adequate contingency measures for potential, additional emissions reductions in the 

event that future violations of the 1997 8-hour ozone NAAQS are observed in the area. 

The Air Program has prepared a comprehensive emissions inventory of the precursors of ozone 

completed for the “attainment” year 2008, and has prepared projections of the emissions 

inventory to 2025. These emissions projections indicate that emissions levels in the St. Louis 

nonattainment area will continue to decrease from attainment year 2008 levels, thereby 

maintaining the ozone NAAQS in future years. The state commits to continue to operate an 

appropriate air quality monitoring network to verify the maintenance of the attainment status 

once the area has been redesignated and to prepare a second maintenance plan 8 years after 

redesignation. The Air Program has the legal authority to implement and enforce all control 

measures. This maintenance plan has been prepared in accordance with the requirements of the 

CAA and in conjunction with EPA staff and guidance documents. 

 
The Missouri Air Conservation Commission ADOPTS the following action 

on this 24th day of April, 2014: 

Missouri State Implementation Plan Revision - SupplementlRevision to the 

Redesignation Demonstration and Maintenance Plan for the Missouri 

Portion ofthe St. Louis Nonattainment Area for the 1997 8-Hour 

Ground-Level Ozone National Ambient Air Quality Standard 

f .J 

--;h~~.""7"#-- I I-2:~:!::========~-' Chairman CJ 

---,I~-"'IiI::I!~~:--=~~:..!IE;t.4-1L-_-~______, Vice Chairman 

, Member 

_______________________,Member 

_______________________,Member 

____________________________,Member 

Jay Nixon, Governor 

Sara Parker Pauley, Director

Air Pollution Control Program

State Plan Actions                                                                    

On Public Notice | Proposed for Adoption

On Public Notice 

Missouri State Implementation Plan Revision - Supplement/Revision to the 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 

The Missouri Department of Natural Resources’ Air Pollution Control Program (Air Program) 

is in the process of redesignating the St. Louis area to attainment for the 1997 ozone 

NAAQS. On Nov. 27, 2011, the Missouri Air Conservation Commission adopted the 

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

Nonattainment Area for the 1997 Ozone NAAQS. The plan was then submitted to the U.S. 

Environmental Protection Agency (EPA) on Nov. 28, 2011 for inclusion in the Missouri State 

Implementation Plan. The plan was not acted upon at that time due to litigation 

surrounding the federal interstate air pollution transport rules. The Air Program is now 

proposing a technical supplement/revision to the 2011 plan. This revision will make 

corrections to the emissions inventories in the plan and update the future year projections 

of the plan from 2022 to 2025.

Proposed Supplement/Revision to the 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 

Appendix A 

Appendix B

Appendix C

Appendix D

Appendix E

Appendix F

Appendix G

Appendix H 

Submit Comments Now 

State Plan Actions on Public Notice - DNR Page 1 of 3

http://www.dnr.mo.gov/env/apcp/stateplanrevisions.htm 2/24/2014
A public hearing is scheduled for this plan action on March 27, 2014. Comments about this 

plan action will be accepted through the close of business on April 3, 2014.

Proposed for Adoption

Missouri State Implementation Plan Revision - Supplement/Revision to the Redesignation Demonstration 

and Maintenance Plan for the Missouri Portion of the St. Louis Nonattainment Area for the 1997 Annual 

Fine Particulate Matter National Ambient Air Quality Standard

Based on monitoring data from 2007-2009, the St. Louis nonattainment area achieved 

attainment of the 1997 annual fine particulate matter (PM2.5) national ambient air quality 

standard (NAAQS). In August 2011, the Missouri Air Conservation Commission adopted the 

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

Nonattainment Area for the 1997 Annual PM2.5 NAAQS. This plan was then submitted to 

the U.S. Environmental Protection Agency for inclusion in the Missouri State 

Implementation Plan. The Missouri Department of Natural Resources Air Pollution Control 

Program has developed a technical supplement/revision to this plan. The technical 

supplement/revision to this plan makes corrections to the emissions inventories included in 

the plan, includes emissions inventories and a discussion on controls for the Illinois portion 

of the nonattainment area, and changes the future year of the plan from 2022 to 2025.

This technical supplement also establishes motor vehicle emissions budgets to be used in 

regional transportation conformity determinations for the base year (2008) and the future 

year (2025) of the plan. Through this SIP submittal, the Missouri Department of Natural 

Resources Air Pollution Control Program is requesting that:

EPA redesignate the Missouri Portion of the St. Louis 1997 PM2.5 nonattainment area 

to attainment pursuant to the provisions of the Clean Air Act, section 107;

•

Concurrently, EPA approve the associated maintenance plan as a revision to the State 

Implementation Plan (SIP) meeting the requirements of the Clean Air Act, section 

175A;

•

That EPA approve the 2008 base year inventory as meeting the requirements under 

Clean Air Action section 172(c)(3); and

•

Approve the Motor Vehicle Emissions Budgets (MVEBs) for the years 2008 and 2025 

pursuant to Clean Air Act Section 176(c).

•

Proposed Supplement/Revision to the Redesignation Demonstration and Maintenance Plan 

for the Missouri Portion of the St. Louis Nonattainment Area for the 1997 Annual Fine 

Particulate Matter National Ambient Air Quality Standard

Appendices A through L

A public hearing was held for this plan action on January 30, 2014. Comments about this 

plan action were accepted through the close of business on February 6, 2014.

State Plan Actions on Public Notice - DNR Page 2 of 3

http://www.dnr.mo.gov/env/apcp/stateplanrevisions.htm 2/24/2014
Missouri State Implementation Plan Revision - Limited Maintenance Plan for the St. Louis Nonclassifiable 

Maintenance Area for the 8-Hour Carbon Monoxide National Ambient Air Quality Standard

The initial maintenance plan for the St. Louis nonclassifiable Carbon Monoxide (CO) 

maintenance area ensured attainment of the CO NAAQS through 2008. Pursuant to Section 

175A(b) of the Clean Air Act, the State must submit a subsequent plan revision for 

maintaining the standard for an additional 10 year period after the expiration of the first 

maintenance period. The Air Program has developed a second maintenance plan that 

provides for continued attainment of the 8-hour CO NAAQS for the St. Louis area from 2008 

through 2018. The plan provides assurances that, in the event of a subsequent violation of 

the CO NAAQS, additional control options, called contingency measures, can quickly be 

implemented to prevent any future violations. In addition, this plan includes CO ambient 

air quality monitoring data from the last seven years and an updated emission inventory for 

average winter day CO emissions in the St. Louis area.   

Proposed Revision to Limited Maintenance Plan for the St. Louis Nonclassifiable 

Maintenance Area for the 8-Hour Carbon Monoxide National Ambient Air Quality Standard

Appendices A and B

A public hearing was held for this plan action on January 30, 2014. Comments about this 

plan action were accepted through the close of business on February 6, 2014.

Missouri State Implementation Plan Revision - Americold Logistics, LLC 24-Hour Particulate Matter (PM10) 

National Ambient Air Quality Standard (NAAQS) Consent Judgment

As required by Section 110(a) of the Clean Air Act, Missouri’s State Implementation Plan 

(SIP) must ensure attainment and maintenance of all National Ambient Air Quality 

Standards (NAAQS).   The Missouri Department of Natural Resources’ Air Pollution Control 

Program is proposing to amend and strengthen the Missouri SIP to address violations of the 

24-hour coarse particulate matter (PM10) NAAQS of 150 micrograms per cubic meter 

(μg/m3) near the Americold Logistics, LLC’s Carthage Crushed Limestone (CCL) facility.

The SIP revision consists of a consent judgment with CCL for measures intended to reduce 

PM10 emissions at the facility, all of which are scheduled for installation and operation by 

March 31, 2014. 

Proposed CCL PM10 SIP Revision 

Attachment 2 – Proposed CCL Consent Judgment 

Exempt Equipment List

A public hearing was held for this plan action on January 30, 2014. Comments about this 

plan action were accepted through the close of business on February 6, 2014.

Back to top

State Plan Actions on Public Notice - DNR Page 3 of 3

http://www.dnr.mo.gov/env/apcp/stateplanrevisions.htm 2/24/2014

1

Bechtel, Cheri

From: Missouri DNR <MODNR@public.govdelivery.com>

Sent: Monday, February 24, 2014 9:04 AM

To: Bungart, Renee; Archer, Larry; Beydler, Van; Lovejoy, Victoria; Moore, Kyra; Vit, Wendy; 

Bechtel, Cheri; Crawford, Betsy; Terlizzi, Gena

Subject: Courtesy Copy: Missouri DNR Air Public Notices Update - Missouri Air Conservation 

Commission Public Hearing, March 27, 2014

This is a courtesy copy of an email bulletin sent by Cheri Bechtel.

This bulletin was sent to the following groups of people:

Subscribers of Air Public Notices (548 recipients) 

Having trouble viewing this email? View it as a Web page.

MISSOURI AIR CONSERVATION COMMISSION 

WILL HOLD PUBLIC HEARING 

JEFFERSON CITY, MO -- The Missouri Air Conservation Commission will hold a public hearing on 

Thursday, March 27, 2014 beginning at 9 a.m. at the Lamplighter Inn, 2820 N Glenstone Ave, Missouri Two 

Meeting Room, Springfield, Missouri. The commission will hear testimony related to the following proposed 

action(s): 

* Missouri State Implementation Plan Revision – Supplement/Revision to the 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 

 

The Missouri Department of Natural Resources’ Air Pollution Control Program (Air Program) is in 

the process of redesignating the St. Louis area to attainment for the 1997 ozone NAAQS. On 

November 27, 2011, the Missouri Air Conservation Commission adopted the Redesignation 

Demonstration and Maintenance Plan for the Missouri Portion of the St. Louis Nonattainment Area 

for the 1997 Ozone NAAQS. The plan was then submitted to the U.S. Environmental Protection 

Agency (EPA) on November 28, 2011 for inclusion in the Missouri State Implementation Plan. The 

plan was not acted upon at that time due to litigation surrounding the federal interstate air pollution 

transport rules. The Air Program is now proposing a technical supplement/revision to the 2011 plan. 

This revision will make corrections to the emissions inventories in the plan and update the future year 

projections of the plan from 2022 to 2025. 

 

If the Commission adopts the action(s), it will be the Department’s intention to submit the action(s) to the 

U.S. Environmental Protection Agency to be included in Missouri’s State Implementation Plan. 
2

 

Documents for the above item(s) will be available for review at the Missouri Department of Natural 

Resources, Air Pollution Control Program, 1659 Elm Street, Jefferson City, (573) 751-4817 and in the Public 

Notices section of the program web site http://dnr.mo.gov/env/apcp/public-notices.htm. This information will 

be available at least 30 days prior to the public hearing date. 

The Department will accept written or email comments for the record until 5 p.m. on April 3, 2014. Please 

send written comments to Chief, Air Quality Planning Section, Air Pollution Control Program, P.O. Box 176, 

Jefferson City, MO 65102-0176. Email comments may be submitted via the program web site noted above. 

All written and email comments and public hearing testimony will be equally considered. 

 

Citizens wishing to speak at the public hearing should notify the secretary to the Missouri Air Conservation 

Commission, Missouri Department of Natural Resources, Air Pollution Control Program, P.O. Box 176, 

Jefferson City, Missouri 65102-0176, or telephone (573) 526-3420. The Department requests persons 

intending to give verbal presentations also provide a written copy of their testimony to the commission 

secretary at the time of the public hearing. 

 

Persons with disabilities requiring special services or accommodations to attend the meeting can make 

arrangements by calling the Program directly at (573) 751-4817, the Division of Environmental Quality's toll 

free number at (800) 361-4827, or by writing two weeks in advance of the meeting to: Missouri Department 

of Natural Resources, Air Conservation Commission Secretary, P.O. Box 176, Jefferson City, MO 65102. 

Hearing impaired persons may contact the program through Relay Missouri, (800) 735-2966. 

You are subscribed to the Air Public Notices topic for Missouri DNR. This information has recently been 

updated, and is now available at the link below. Thank you for your interest in the Air Public Notices. 

 

 

Celebrating 40 years of taking care of Missouri's natural resources. To learn more visit dnr.mo.gov.

http://dnr.mo.gov/env/apcp/stateplanrevisions.htm

 

Update your subscriptions, modify your password or email address, or stop subscriptions at any time on your 

Subscriber Preferences Page. You will need to use your email address to log in. If you have questions or 

problems with the subscription service, please contact subscriberhelp.govdelivery.com. 

This service is provided to you at no charge by Missouri DNR. 
 PUBLIC HEARING 3/27/2014

www.midwestlitigation.com Phone: 1.800.280.3376 Fax: 314.644.1334

MIDWEST LITIGATION SERVICES

Page 1

1 BEFORE THE MISSOURI AIR CONSERVATION COMMISSION

 ADMINISTRATIVE HEARING COMMISSION

2

3

4 IN THE MATTER OF: )

 )

5 Missouri State )

Implementation Plan )

6 Revision - )

Supplement/Revision to )

7 the Redesignation )

Demonstration and )

8 Maintenance Plan for the)

Missouri Portion of the )

9 St. Louis Nonattainment )

Area for the 1997 8-Hour)

10 Ground-Level Ozone )

National Ambient Air )

11 Quality Standard. )

12

13

14 REPORTER'S TRANSCRIPT

15 OF

16 PUBLIC HEARING

17

18 Taken on Thursday, March 27, 2014

19 Commencing at 9:17 o'clock a.m.

20 At Lamplighter Inn, Missouri Two

21 2820 N. Glenstone Avenue

22 Springfield, Missouri

23

24

25 REPORTED BY: PAULA C. VOYLES, CCR, RPR, CRR
 PUBLIC HEARING 3/27/2014

www.midwestlitigation.com Phone: 1.800.280.3376 Fax: 314.644.1334

MIDWEST LITIGATION SERVICES

Page 4

1 P R O C E E D I N G S

2

3 CHAIRMAN PENDERGRASS: The hearing will

4 come to order. Let the record show that the

5 following commissioners are present: Jack Baker,

6 Mark Garnett, Gary Pendergrass, and David

7 Zimmermann.

8 The Air Conservation Commission of the

9 State of Missouri has called this public hearing

10 pursuant to Section 643.070, Revised Statutes of

11 Missouri; EPA promulgated rule 40 CFR 51.102, for

12 the purpose of hearing testimony related to:

13 Missouri State Implementation Plan

14 Revision, Supplement/Revision to the Redesignation

15 Demonstration and Maintenance Plan for the Missouri

16 portion of the St. Louis Nonattainment Area for the

17 1997 8-Hour Ground-Level Ozone National Ambient Air

18 Quality Standard.

19 The hearing record will close at 5 p.m.

20 on April 3rd, 2014.

21 Anyone who has not been scheduled to

22 appear, but who wishes to be heard, should indicate

23 that you wish to speak on the sign-in sheets

24 available at the door or by letting the Commission

25 know by telephone after the public hearing has been
 PUBLIC HEARING 3/27/2014

www.midwestlitigation.com Phone: 1.800.280.3376 Fax: 314.644.1334

MIDWEST LITIGATION SERVICES

Page 6

1 of Natural Resources' website at least 30 days prior

2 to this public hearing.

3 In addition to making the proposed plan

4 available for viewing and comment, the Air Pollution

5 Control Program distributed the public hearing

6 notice to over 480 citizens, organizations,

7 corporations, associations, and elected officials.

8 Finally, we notified the Kansas City, St. Louis

9 County, and Springfield local air pollution control

10 agencies; Illinois, Kansas and other surrounding

11 states; and the U.S. Environmental Protection Agency

12 of this public hearing.

13 Chairman, this concludes my testimony.

14 CHAIRMAN PENDERGRASS: Okay. I have

15 Andy Knott -- I'm sorry. Can we back up just a

16 minute. I apologize for that. Joe Winkelmann.

17 (Whereupon, Mr. Joe Winkelmann

18 was duly sworn by the court reporter.)

19 EXAMINATION

20 MR. WINKELMANN: Good morning, Chairman,

21 members of the Commission: My name is Joe

22 Winkelmann. I'm employed as an environmental

23 engineer with the Missouri Department of Natural

24 Resources' Air Pollution Control Program, or Air

25 Program, at 1659 East Elm Street, Jefferson City,
 PUBLIC HEARING 3/27/2014

www.midwestlitigation.com Phone: 1.800.280.3376 Fax: 314.644.1334

MIDWEST LITIGATION SERVICES

Page 7

1 Missouri.

2 I am here today to present testimony on

3 the proposed Missouri State Implementation Plan, or

4 SIP, revision entitled Supplement to the

5 Redesignation Demonstration and Maintenance Plan for

6 the Missouri Portion of the St. Louis Nonattainment

7 Area for the 1997 8-Hour Ground-Level Ozone National

8 Ambient Air Quality Standard, or NAAQS. The

9 proposal for the plan can be found on page 81 of

10 your briefing document.

11 Ozone air quality has dramatically

12 improved in the St. Louis area as a result of

13 implementation of State and Federal control measures

14 since the designation of the St. Louis area as

15 nonattainment in 2004. On June 9th, 2011, EPA

16 issued a "Clean Data Determination" that the entire

17 St. Louis Nonattainment Area achieved at lease three

18 consecutive ozone seasons (2008-2010) of complete,

19 quality assured ambient air quality monitoring data

20 demonstrating attainment with the 0.080 parts per

21 million, or ppm, 8-hour ozone NAAQS promulgated in

22 1997. The air quality monitoring data for the most

23 recent years of 2011 to 2013 also shows compliance

24 with the 1997 NAAQS. These air quality improvements

25 are due to permanent enforceable emission control
RECOMMENDATION FOR ADOPTION 

PROPOSED REVISION TO 

MISSOURI STATE IMPLEMENTATION PLAN – 

SUPPLEMENT/REVISION TO THE 

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 

On March 27, 2014, the Missouri Air Conservation Commission held a public hearing 

concerning a revision to the Missouri State Implementation Plan (SIP) for the 

Supplement/Revision to the 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. A summary of comments received, and the Air 

Program’s corresponding responses, is included on the following page. Revisions were made to 

the proposed plan as a result of comments received. 

The revised plan has not been reprinted in the briefing document due to its volume. The entire 

revised plan is available for review at the Missouri Department of Natural Resources’ Air 

Pollution Control Program, 1659 East Elm Street, Jefferson City, Missouri, 65101, (573)751-

4817. It is also available online at http://dnr.mo.gov/env/apcp/stateplanrevisions.htm. 

The Air Program recommends the commission adopt the plan as revised. If the commission 

adopts this plan, it will be the department’s intention to submit it to the U.S. Environmental 

Protection Agency for inclusion in the Missouri State Implementation Plan. 

 
COMMENTS AND RESPONSES ON 

PROPOSED REVISION TO 

MISSOURI STATE IMPLEMENTATION PLAN – 

SUPPLEMENT/REVISION TO THE 

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 

The public comment period for the proposed revision to the Missouri State Implementation Plan 

(SIP) for the Supplement/Revision to the 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 (NAAQS) opened on February 24, 2014 and 

closed on April 3, 2014. Revisions to the proposed plan were made as a result of comments.

The following is a summary of comments received and the Missouri Department of Natural 

Resources’ Air Pollution Control Program’s (Air Program’s) corresponding responses. Any 

changes to the proposed plan are included in the response to comments. 

SUMMARY OF COMMENTS: During the public comment period for the proposed plan, the 

Air Program received six (6) comments from the Sierra Club and two (2) comments from the 

U.S. Environmental Protection Agency (EPA). 

COMMENT #1: Sierra Club commented on the health effects of high ozone concentrations. They 

pointed out several facts regarding the amount of asthma cases in the St. Louis area and how these 

figures compare with the rest of the state and country. 

RESPONSE AND EXPLANATION OF CHANGE: The Air Program acknowledges the effects 

of ozone on certain health and respiratory conditions, and it is the Air Program’s mission to 

protect air quality in the state to ensure the safety of public health. This redesignation 

demonstration and maintenance plan will add an extra layer of protection for public health in the 

St. Louis area against elevated ozone concentrations, if it is adopted by the commission. The 

maintenance plan establishes a contingency plan that commits the state to implement additional 

control measures designed to address high ozone concentrations and safeguard against potential 

future elevated ozone concentrations. Additionally, this plan maintains control requirements 

currently in place in the St. Louis area. 

As a result of this comment, additional language has been added to the executive summary and 

Chapter 1 (Introduction/Purpose) of the plan to more clearly explain the extra layer of 

environmental and public health protection for the St. Louis area through the potential 

implementation of contingency measures if triggered in the future. 

COMMENT #2: Sierra Club commented that there are five separate criteria that must be met in 

order for a nonattainment area to be redesignated to attainment. They specified that the 
improvement in air quality must be due to permanent and enforceable control measures and not the 

result of favorable meteorology or economic downturn. 

RESPONSE: This plan addresses each of the five criteria including the requirement that the 

improvement in air quality results from permanent and enforceable emission reductions. The 

redesignation demonstration portion of the plan compares the level of oxides of nitrogen (NOx) 

and volatile organic compounds (VOC) emissions from 2002, when the area was in nonattainment, 

to emissions from the attainment year of 2008. This demonstration shows that total NOx emissions 

in the Missouri portion of the St. Louis (MO-St. Louis) nonattainment area from all sources have 

decreased a substantial 33% between 2002 and 2008. This NOx emissions reduction occurs despite 

the fact that both electricity production and vehicle miles travel increased within the MO-St. Louis 

area during this same timeframe: Power demand from electric generating units (EGUs) in the area 

increased by approximately 12% while vehicle miles traveled (VMT) increased by approximately 

6%. During this period, NOx emissions from EGUs in the MO-St. Louis nonattainment area 

reduced by approximately 5,000 tons per ozone season (~33 tons/day), and NOx emissions from 

on-road mobile sources decreased by over 62 tons/day. Since electricity production and VMT 

grew between these two years, the emission reductions cannot be attributed to economic factors 

such as a downturn, but rather are the result of the implementation of enforceable emission control 

measures that have substantially reduced the rate at which NOx emissions are emitted from both 

the stationary and mobile source categories. 

 

The 33% reduction in total NOx emissions in the MO-St. Louis nonattainment area also supports 

the conclusion that improvement in air quality was not based on favorable meteorology, but rather 

emission reductions. Figure 1 below displays the maximum 3-year design values for 8-hour ozone 

concentrations from 2000–2013 for all of the MO-St. Louis nonattainment area ozone monitors 

(dashed line). Based on EPA’s Guideline on Air Quality Models found in 40 CFR 51 Appendix 

W, a stable distribution of meteorological conditions occurs over a period in excess of 10 years. 

With data spanning more than 10 years, the figure does not skew the results towards favorable or 

unfavorable meteorological conditions. The horizontal line indicates the level of violation of the 

1997 8-hour ozone standard. The bold represents the best-fit trend-line for the maximum design 

value concentrations of all operating monitors each year. The chart shows spikes and valleys for 

each ozone monitor, which is most likely the result of varying (favorable and unfavorable) 

meteorology during these years, but the trend-line shows that maximum recorded ozone 

concentrations in the MO-St. Louis area have been declining over the past 13 years despite the 

fluctuations in yearly meteorology. This demonstrates that favorable meteorology is not 

responsible for the declining trend in ozone concentrations experienced in the St. Louis area over 

the last 13 years. The plan asserts that the decrease in ozone concentrations is in fact due to 

permanent and enforceable emission reductions, both regional and local. No changes to the plan 

were made as a result of this comment. 
Figure 1: Evaluation of Maximum Ozone Design Values from 2001-2013 

COMMENT #3: Sierra Club commented that emission reductions resulting from the NOx Budget 

Program and the Clean Air Interstate Rule (CAIR) cannot be relied upon as permanent and 

enforceable because they allow for the trading/purchasing of emission credits across the entire 

eastern third of the country, and it is possible that the trading program could cease in the future. 

RESPONSE: The Air Program considered the effects of federal trading programs on EGU 

emissions inside the nonattainment area. The EGU emissions in the MO-St. Louis nonattainment 

area that are subject to CAIR were evaluated from 2009–2013. Since the CAIR NOx Ozone 

Season trading program began in 2009, the EGUs subject to CAIR inside the MO-St. Louis 

nonattainment area have not once exceeded their ozone season NOx CAIR allotments in aggregate 

during any control period from 2009–2013. All of the EGUs subject to CAIR in the MO-St. Louis 

60

65

70

75

80

85

90

95

100

01-03 02-04 03-05 04-06 05-07 06-08 07-09 08-10 09-11 10-12 11-13^

Concentration (ppb)

Violation of the 1997 NAAQS

Max STL Design Value

Max Design Value Trendline

^Quality assured data

through Dec 31st, 2013

Ozone Season: Apri l 1 to October 31
nonattainment area are owned by Ameren. Ameren has participated in emission credits trading in 

the past, as is allowed under CAIR. The unit level CAIR allotments are occasionally exceeded 

from year to year. However, since CAIR began, any MO-St. Louis area EGU units that have 

exceeded their CAIR allotments have been offset by other units within the nonattainment area that 

held emissions below their CAIR allotments. Therefore, since 2009, total ozone season NOx

emissions from EGUs in the MO-St. Louis nonattainment area have been below the level of their 

total CAIR allotments each year. Ameren has complied with the NOx Ozone Season CAIR 

Program without purchasing or trading allowances from outside the nonattainment area. Instead, 

Ameren has relied on integral low NOx burners and over-fire air to control NOx emissions from 

these EGUs. Because these devices are built-in or inherent to the combustion process and work by 

increasing combustion efficiency, Ameren is not expected to uninstall this inherent control 

technology to purchase allowances. Additionally, if Ameren did elect to uninstall the current 

control technology on any of these units, and the change triggered a major modification, then 

Ameren would be subject to New Source Review (NSR) permitting requirements. In a 

nonattainment area (based on a new standard) these provisions would require NAAQS impact 

modeling and implementation of control devices at the lowest achievable emission rates (LAER). 

The maintenance demonstration included with this proposed SIP revision projects future EGU 

emissions in the MO-St. Louis nonattainment area. As mentioned in Chapter 5 of the plan, 

although NOx Ozone Season CAIR allotments decrease 17% by 2015 when compared to 

allotments granted in 2009–2014, the Air Program did not project future year EGU emissions 

based on the 2015 allotments. Instead, the plan projects EGU emissions in the area to remain 

constant from the average levels from 2008–2011. This a very conservative estimate, especially 

considering the fact that NOx ozone season emissions from EGUs in the MO-St. Louis 

nonattainment area have continued to decrease in the last two years and have actually been below 

the 2015 allotments in aggregate for the last two years. 

In addition, EPA has maintained that emission reductions from trading programs are permanent 

and enforceable. EPA has noted this during several recent SIP approvals, including the CincinnatiHamilton Fine Particulate Matter (PM2.5) area redesignation: 

Further, EPA disagrees with the Commenter’s conclusion that emission reductions 

associated with trading programs such as the NOX SIP Call, CAIR, and CSAPR are not 

permanent and enforceable simply because the underlying program is an emissions 

trading program... EPA disagrees with the Commenter’s conclusion that reductions 

from trading programs can’t be considered permanent and enforceable because these 

programs allow individual sources to choose between purchasing emission credits and 

reducing emissions. [76 FR 80255]

The Air Program has addressed the commenter’s concern, about the possibility that the CAIR 

program will end, in Chapter 4 of the proposed plan. To summarize, CAIR has been remanded to 

EPA by the courts, and in 2011, EPA promulgated a replacement rule known as the cross-state air 

pollution rule (CSAPR). However, the D. C. Circuit court vacated the CSAPR in December 2011 

and explicitly directed EPA to continue implementing CAIR until an acceptable rule that addresses 

the court’s concerns is promulgated. Based on anti-backsliding provisions contained in the Clean 

Air Act, any replacement rule for CAIR must be equivalent or better. Because of this, CAIR is 
considered a permanent and enforceable federal control program that meets the requirements of 

CAA Section 107(d)(3)(E)(iii) for redesignation purposes. EPA has weighed in similarly. During 

the redesignation of the Indianapolis PM2.5 area, EPA states that CAIR reductions are permanent 

and enforceable even if the rule is due to be replaced: 

However, EPA disagrees that the Court’s instruction in those two cases forecloses the 

Agency and states from relying on CAIR for purposes such as redesignating an area from 

nonattainment to attainment. Subsection (iii) of section 107(d)(3)(E) is a backwards 

looking requirement; it requires that the attainment air quality in the area is ‘‘due to’’ 

permanent and enforceable emissions reductions. The purpose of this requirement is to 

ensure that in redesignating areas from nonattainment to attainment, EPA does not rely 

on ephemeral, temporarily improved air quality that results from circumstances such as 

temporary shutdowns of plants or reduced emission rates because of slowed 

production... The anticipation that CAIR may be replaced during the maintenance 

period by another rule requiring upwind sources to reduce emissions does not require 

EPA to disapprove the redesignation request for Indianapolis currently before it. EPA’s 

longstanding interpretation of section 107(d)(3)(E) in the Calcagni Memorandum 

contemplates that some reductions required by existing control measures may be 

replaced in the future by other measures... Therefore, the commenter’s concern that a 

future replacement rule might not require the same reductions as CAIR is not a bar to 

approving Indiana’s redesignation request today. [78 FR 41700-41701]

Lastly, states must be able to assume that regulations at the federal level are useable for credit in 

the SIP. EPA reiterates this in the Indianapolis area redesignation: 

The structure of section 107(d)(3)(E)(iii) indicates that the CAA generally considers 

reductions resulting from SIPs and Federal regulations as permanent and enforceable. It 

references ‘‘other’’ reductions that are comparable to measures adopted into SIPs or 

Federally adopted regulations and can therefore also qualify as permanent and 

enforceable reductions, indicating that, in general, SIP reductions and reductions from 

Federal regulations are the types of reductions that the CAA views in the first instance as 

having the requisite permanence and enforceability for purposes of redesignation. [78 FR 

41701]

 No changes were made to the plan as a result of this comment. 

COMMENT #4: Sierra Club commented that NAAQS are not an air quality target to be hit one 

time. The Sierra Club points out that the area violated the standard based on 2010–2012 air quality 

data, and asked what is to prevent the area from violating the NAAQS in the future. Sierra Club 

cites that the Illinois portion of the nonattainment area has already been redesignated to attainment 

and is also a party to the 2010-2012 ozone air quality violation. 

RESPONSE AND EXPLANATION OF CHANGE: The SIP must provide for attainment and 

maintenance of the NAAQS at all times. However, SIPs cannot foresee every possible situation 

and provide a guarantee that air quality will never exceed or violate a specific standard, especially 

for a pollutant such as ozone, where meteorology plays such a significant role in its photochemical 
formation. For this reason, the Air Program emphasizes the importance of establishing the 

contingency measures contained in this maintenance plan, which would be implemented if future 

violations of the 1997 ozone NAAQS occur due to these unforeseen occurrences. 

The summer of 2012 was among the hottest summers on record for the Midwest United States, and 

devastating droughts limited precipitation across the region to well-below-average levels. Despite 

this record-setting summer, only one monitor out of twelve operational monitors in the St. Louis 

area recorded a violation of the 1997 ozone NAAQS with a design value of 86 ppb from 2010–

2012 (due to regulatory rounding conventions 85 ppb is considered a violation of the 1997 ozone 

NAAQS). In other words, violations of the 1997 ozone NAAQS concentrations across the entire 

St. Louis area as a region are not occurring and have not occurred since the area originally attained 

back in 2009. 

As the country recovers from the recession and VMT, population, and electricity demand grow, 

emissions levels from the largest source categories continue to decline, and ozone concentrations 

are trending downwards. All monitors in the 1997 St. Louis ozone nonattainment area are in 

compliance with the 1997 ozone NAAQS based on 2011 – 2013 air quality data. It is important to 

note, that the area is attaining even though the unusually high 2012 ozone season is still included 

in the 2011-2013 design value for the area. 

Furthermore, ozone precursor emissions decreased from 2012 to 2013. Regulatory ozone season 

NOx emissions from EGUs within the MO-St. Louis nonattainment area declined by 248 tons from 

2012 to 2013. In addition, ozone season NOx and VOC emissions from on-road sources in the 

MO-St. Louis nonattainment area declined by approximately 265 tons and 407 tons, respectively, 

as a result of federal motor vehicle emission standards and fleet turnover. Moreover, motor 

vehicle emission standards are expected to continue to drop as a result of the recently promulgated 

federal Tier 3 standards to be implemented starting in the 2017 model year. 

Since the summer of 2012, the Air program has implemented grant projects through the Diesel 

Emissions Reduction Act for engine repowers on three (3) tugboats operating exclusively inside 

the nonattainment area, an engine repower for one (1) switch locomotive operating in the 

nonattainment area, an early replacement for a long-haul tractor trailer operating inside the 

nonattainment area, and tailpipe/idle reduction retrofits for 23 school buses operating in Jefferson 

County. These projects have further reduced NOx and VOC emissions in the nonattainment area 

since 2012 and are contributing to the continued declining trend in ozone concentrations. 

In regard to the Illinois portion of the nonattainment area, the plan mentions that the four Illinois 

counties on the Metro-east side of the area have been redesignated to attainment. For the violation 

of the 1997 ozone NAAQS based on 2010–2012 air quality data, only one out of twelve air quality 

monitors in the area was out of compliance, and the location of that monitor was on the Missouri 

side of the nonattainment area. In response, Illinois implemented a contingency measure pursuant 

to their approved maintenance plan. The Air Program again notes the importance of the 

contingency plan associated with Missouri’s redesignation request and maintenance plan for the 

area. If another triggering event and/or violation of the NAAQS occurs in the region, the Illinois 

EPA and the Air Program would work together to determine the cause and implement contingency 

measures to further limit and reduce emissions in the area. 
As a result of this comment, additional language has been added to the plan to provide a discussion 

of the emissions reductions achieved in the MO-St. Louis area since the summer of 2012 in an 

effort to demonstrate that emissions of ozone precursors within the nonattainment area continue to 

decline as a result of both permanent voluntary projects and permanent and enforceable control 

measures. 

COMMENT #5: Sierra Club commented that a newer, more protective 2008 ozone NAAQS has 

been promulgated and that an even more stringent ozone standard is expected to be proposed by 

EPA in the near future. They noted that the St. Louis area is currently designated as a marginal 

nonattainment area for the 2008 ozone NAAQS, and that the area will be reclassified from 

marginal to moderate classification under the 2008 ozone NAAQS if the area fails to attain by the 

attainment deadline for marginal areas. The Sierra Club suggests a more proactive approach, 

stating that the Air Program should use its minimal resources to address these newer, more 

protective NAAQS, as opposed to addressing the older 1997 ozone standard. 

RESPONSE AND EXPLANATION OF CHANGE: The Air Program is currently developing a 

marginal area SIP submission to address the area’s marginal nonattainment designation under the 

2008 ozone NAAQS. If the downward trend of ozone precursor emissions described in the plan, 

and elsewhere here, is not enough to comply with the 2008 ozone NAAQS by the attainment date 

of December 31, 2015 and the area is reclassified to moderate, the State’s obligations become 

more stringent and the Air Program will be required to address them at that time. This 

redesignation of the MO-St. Louis area to attainment for the 1997 ozone standard has no effect on 

the attainment or implementation of the 2008 NAAQS. By redesignating the MO-St. Louis area to 

attainment under the 1997 standard, the Air Program is putting contingency measures in place and 

concluding our planning obligations under the 1997 NAAQS. 

The Air Program is taking a proactive approach through this redesignation request by reducing 

uncertainty regarding the State’s planning obligations for the old standard. This allows the Air 

Program to focus its limited resources on the current, more protective 2008 ozone standard, as well 

as a more stringent ozone standard anticipated in late 2015. The Air Program has already 

developed an Early Progress Plan for the St. Louis marginal ozone nonattainment area in order to 

establish motor vehicle emission budgets for the area under the 2008 NAAQS. The Air Program is 

also nearing completion of a SIP revision under Section 182(a) of the Clean Air Act in order to 

address the state’s planning obligations for the marginal ozone nonattainment area. Furthermore, 

because of the possibility that St. Louis could be reclassified from marginal to moderate under the 

2008 standard and classified moderate or higher under the revised ozone NAAQS expected in late 

2015, the Air Program is currently reviewing 2018 emissions inventory projections and modeling 

input files in an early effort to develop a modeling construct to support any additional planning 

requirements in the event these scenarios occur. Both of these situations would require the Air 

Program to develop an attainment demonstration and a reasonable further progress plan under 

Section 182(b) of the Clean Air Act. 

As a result of this comment, additional language has been added to the Executive Summary and 

Chapter 1 (Introduction/Purpose) of the plan to explain that a newer, more protective ozone 

NAAQS is in place and that an even more stringent ozone NAAQS is expected to be established in 
the near future. The approval of this plan will conclude any obligations under the 1997 standard 

prior to its revocation, allowing the Air Program to focus its resources on addressing these newer, 

more protective ozone NAAQS. 

COMMENT #6: Sierra Club commented that the Air Program should get out ahead of the issue 

and require controls on large stationary sources. They state that controlling stationary sources 

provides a much higher level of emission reduction certainty than relying on motor vehicle fleet 

turnover. 

RESPONSE: Based on the Air Program’s 2008 comprehensive baseline emissions inventory for 

the MO-St. Louis nonattainment area included with this plan, on-road motor vehicle emissions 

comprise over 50% and 25% of total NOx and VOC emissions, respectively. Whereas, point 

sources (i.e., large stationary sources) only comprise 28% and 8% of total NOx and VOC 

emissions, respectively. Since on-road motor vehicles contribute such a large percentage to the 

overall emissions inventory these emissions should be addressed in order to reduce ozone 

concentrations effectively. Federal motor vehicle engine standards are permanent and enforced by 

requiring emission reductions at the engine/vehicle manufacturer level. Because of the continued 

tightening of federal motor vehicle emission standards, each time an older car is retired and 

replaced by a newer car (referred to as ‘fleet turnover’), permanent emission reductions are 

achieved. 

The Air Program develops comprehensive emissions inventories every three years as required by 

EPA’s Air Emissions Reporting Rule. In order to develop on-road motor vehicle emissions, the 

Air Program queries Missouri Department of Revenue data for every registered vehicle in the state 

to determine the age distribution of the vehicle fleet in Missouri. Each year this query is 

performed, there is always a substantial number of the later model year vehicles, meaning that the 

latest model year cars continue to be purchased both in St. Louis and throughout the state on a 

regular basis. As demonstrated in the response to comment #2, emission reductions have outpaced 

VMT growth which can be attributed to regular motor vehicle fleet turnover. 

Moreover, these motor vehicle emission reductions are based on conservative assumptions. The 

maintenance demonstration within this plan employs a 1.5% annual VMT and vehicle source 

population growth rate for motor vehicles in the MO-St. Louis nonattainment area, even though 

the East-West Gateway Council of Governments, the region’s transportation planning agency, 

currently estimates that the MO-St. Louis area VMT is only expected to grow at an annual rate of 

approximately 1% . Additionally, it is noted that the Air Program took no credit in the plan for the 

Federal Tier III motor vehicle engine standards that EPA recently promulgated. These standards 

are expected to significantly reduce NOx and VOC emissions from the mobile source sector and 

provide additional assurance that ozone precursor emissions will continue to decline in the MO-St. 

Louis nonattainment area through permanent and enforceable control measures. Even with the 

conservative assumptions used in the plan, the state still demonstrates that the area will maintain 

the 1997 ozone NAAQS. No changes to the proposed plan were made as a result of this comment. 

COMMENT #7: EPA commented that Missouri should provide additional information to more 

accurately reflect that recent improvements to air quality are due to permanent and enforceable 

emission reductions. 
RESPONSE AND EXPLANATION OF CHANGE: As this comment reflects some of the same 

issues addressed by the Sierra Club in their comments, we defer to the responses to those 

comments in addressing this one as well. Please see the responses to comment #2 and comment #4 

above in regard to recent permanent and enforceable emissions reductions. As a result of this 

comment, additional language has been added to the plan to describe the recent emissions 

reductions since the summer of 2012 that have been achieved in the St. Louis area as a result of 

permanent and enforceable controls. 

COMMENT #8: EPA commented that the Air Program should remove language in Chapter 7 of 

the plan in relation to submitting a second 10-year maintenance plan for the 1997 ozone 

NAAQS. The commitment to submit a second 10-year plan is not necessary for approving this 

current maintenance plan. In the event that a second 10-year maintenance plan is required, EPA’s 

future rulemakings will specifically clarify those requirements. 

RESPONSE AND EXPLANATION OF CHANGE: As a result of this comment, the Air Program 

removed the commitment to develop the second 10-year maintenance plan for the 1997 ozone 

NAAQS from Chapter 7 of the plan. If EPA promulgates a future rule requiring the St. Louis area 

to develop a second 10-year maintenance plan for the 1997 ozone NAAQS, the Air Program would 

address the obligation at that time.