UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 7 

901 NORTH 5TH STREET 

KANSAS CITY, KANSAS 66101 

AUG 17 2012 

MEMORANDUM 

SUBJECT: 

FROM: 

THRU: 

TO: 

Technical Support Document (TSD) for Missouri State Implementation Plan (SIP) revision to 

Missouri Rules 10 CSR 10-6.010 Ambient Air Quality Standards, 

10 CSR 10-6.040 Reference Methods, and 10 CSR 10-6.130 Controlling Emissions During 

Episodes of High Air Pollution Potential 

Amy Bhesania ~ 

Community Partn~ Programs Section 

Michael Jay, Section Chief 

Atmospheric Programs Section 

M0-297; EPA-R07-0AR-2012-0596 

INTRODUCTION 

This State Implementation Plan (SIP) revision is for Missouri Rules 10 CSR 10-6.010AmbientAir Quality 

Standards, 10 CSR 10-6.040 Reference Methods, and 10 CSR 10-6.130 Controlling Emissions During 

Episodes of High Air Pollution Potential. This revision will amend the ambient air quality standards table.to 

reflect revised National Ambient Air Quality Standards (NAAQS), update reference methods associated with 

the revised NAAQS, and update the breakpoint values for the Air Quality Index. The Missouri Department 

ofN atural Resources' (MDNR) Air Pollution Control Program sent this revision request to the EPA on 

September 21, 2010, and it was received by EPA on September.28, 2010. The effective date of these state 

regulations was May 30, 2010. 

DESCRIPTION OF REVISIONS 

The revisions to 10 CSR 10-6.01 0 Ambient Air Quality Standards update the standards to reflect changes 

promulgated by EPA through December 21, 2008 for the National Ambient Air Quality Standards (NAAQS) 

for particulate matter 10 microns or less, particulate matter 2.5 microns or less, ozone and lead. This 

amendment also corrects the 1971 nitrogen dioxide standard in Missouri. 

1. The 1987 annual standard for particular matter 10 microns or less (PM10) of 50 micrograms per cubic 

meter was removed from the table. 

2. The 24-hour standard for particulate matter 2.5 (PM2.5) was revised from 65 micrograms per cubic 

meter to the 2006 24-hour standard of 35 micrograms per cubic meter, and the appropriate reference 

methods associated with this NAAQS were added to the table. 

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3. The appropriate reference methods associated with sulfur dioxide and carbon monoxide were added 

to the table. 

4. The one (I)-hour ozone standard of0.12 parts per million (ppm) was removed and the 2008 eight 

(8)-hour ozone standard of0.075 ppm was added. The appropriate reference methods and form of the 

standard were added to the table. 

5. The words 'photo-chemical oxidants' were removed from the 1997 8-hour ozone pollutant reference 

in the table, but the standard of .08 ppm was retained. 

6. The nitrogen dioxide standard was corrected from 0.05 ppm to 0.053 ppm. 

7. The applicable reference methods associated with hydrogen sulfide and sulfuric acid were added to 

the table. 

8. The 2008lead standard of0.15 micrograms per cubic meter was added to the table. The appropriate 

reference methods and form of the standard were added to the table. 

The revisions to 10 CSR 10-6.040 Reference Methods update the reference methods for measuring ambient 

air concentrations to determine whether areas are attaining the 2008 ozone and lead NAAQS. Additionally, 

the amendment incorporates by reference all reference methods found in 40 CFR Part 50 Appendices A-R as 

well as equivalent methods found in 40 CFR Part 53 into this rule. These appendices describe. the methods 

for measuring ambient concentrations of various pollutants for which NAAQS have been established, and 

describe how attainment of various NAAQS is determined. Section (4) of the rule was amended as follows: 

1. 40 CFR Part 50 Appendices A-Rand 40 CFR part 53 promulgated as of June 30, 2008, and Federal 

Register Notice 73 FR 67051-67062 promulgated November 12, 2008 were incorporated by 

reference in to the rule. 

2. Reference to 40 CFR Part 50 Appendix Q- Reference Method for the Determination of Lead and 

Particulate Matter as PM10 Collected from Ambient Air was added to sub section (4)(G) of the rule. 

3. Sub section (4)(N) was added to the rule which references that compliance with the 8-hour ozone 

standards is determined as specified in 40 CFR part 50, Appendix P -Interpretation of the Primary 

and Secondary National Ambient Air Quality Standards for Ozone 

4. Sub section (4)(0) was added to the rule which references that compliance with the lead standard 

shall be determined as specified in 40 CFR part 50, Appendix R-Interpretation of the National 

Ambient Air Quality Standards for Lead. 

5. Section (9) of the rule was removed. This amendment moves the incorporation by reference of these 

reference methods from 10 CSR 10-6.070 (Missouri's incorporation by reference of the federal 

NSPS requirements in 40 CFR Part 60) to this rule. 10 CSR 10-6.070 was revised to reflect this 

change. 

The revisions to 10 CSR 10-6.130 Controlling Emissions During Episodes of High Air Pollution Potential 

update the breakpoint values in Table A of the Air Quality Index (AQI) for eight-hour ozone. The breakpoint 

values are used to determine whether contingency measures should be implemented during periods of 

excessive air pollutant concentrations. Table A was amended as follows: 

I. The breakpoint value for the 8-hour ozone standard in the AQI range of0-50 was revised from 0 -

0.064 ppm to 0- 0.059 ppm. 

2. The breakpoint value for the 8-hour ozone standard in the AQI range of 51-100 was revised from 

0.065 - 0.084 ppm to 0.060- 0.075 ppm. 

3. The breakpoint value for the 8-hour ozone standard in the AQI range of 101 - 150 was revised from 

0.085-0.104 ppm to 0.076-0.095 ppm. 

4. The breakpoint value for the 8-hour ozone standard in the AQI range of 151-200 was revised from 

0.105-0.124 ppm to 0.096-0.115 ppm. 

5. The breakpoint value for the 8-hour ozone standard in the AQI range of201-300 was revised from 

0.125 - 0.374 ppm to 0.116 - 0.374 ppm. 
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EPA notes that Missouri retained the 1-hour ozone standard breakpoint values and these trigger levels are 

consistent with EPA's significant harm levels (SHL ). EPA is approving the 8-hour breakpoint levels 

because they are more stringent than the existing 8-hour breakpoint values in Missouri's current SIP, and 

because EPA does not have a SHL based on an 8-hour average. 

CONCLUSION 

The revisions in this SIP submittal are largely administrative and consistent with current Federal regulations. 

The revisions will update Missouri's rule and will improve the clarity of the rule. States are not required to 

adopt ambient air quality standards, but are required to implement the standards adopted by EPA pursuant to 

section 110 of the CAA. Missouri has adopted standards which are consistent with the EPA standards, and, 

therefore, this revision to update the state standards is approvable. The revisions do not have an adverse 

affect on air quality and improve the stringency of the SIP. I approve these revisions. 

SOURCES USED 

40 CFR Part 51, Requirements for Preparation, Adoption, and Submittal of Implementation Plans 

http://www.epa.gov/epacfr40/chapt-l.info/chi-toc.htm 

Appendix V to Part 51, Criteria for Determining the Completeness ofPlan Submissions 

40 CFR Part 52, Approval and Promulgation of Implementation Plans 

http://www.epa.gov/epac:fr40/chapt-l.info/chi-toc.htm 

Subpart AA, Missouri 

Federal Register Notice 71 FR 61144-61233, promulgated October 17, 2006 

Federal Register Notice 73 FR 16436-16514, promulgated March 27, 2008 

Federal Register Notice 73 FR 66964-67062, promulgated November 2, 2008 

************************************************************************ 

Record of Rule Making 

Missouri Department of Natural Resources 

Public Hearing December 3, 2009 

Adopted by Missouri Air Conservation Commission 

(MACC) January 28,2010 

Effective Date of Re2ulation May30, 2010 

SIP Submittal sent to EPA Region 7 by MDNR September 21,2010 

Rule Package received by EPA Re2ion 7 September 28,2010 

Completeness letter sent to MDNR April6, 2011