The Missouri Department of Natural Resources develops plans consistent with federal regulations related to National Ambient Air Quality Standards. These plans address additional requirements promulgated by the Environmental Protection Agency to satisfy a mandatory requirement in Section 110 or Part D of the Clean Air Act.

In October 2008, the Missouri Department of Natural Resources’ Air Pollution Control Program undertook a pilot project to develop and implement an AQMP in the Missouri/Illinois bi-state St. Louis area. Instead of the traditional single-pollutant approach to SIP development, the AQMP is intended to address multiple air quality issues, including criteria pollutants and air toxics. This report explains the process of developing and implementing the AQMP in the St. Louis area, identifies lessons learned throughout the process and offers suggestions for moving forward.

Section 128 of the federal Clean Air Act Amendments of 1990 asserts that each SIP should contain provisions regarding conflicts of interest and providing for representation of the public interest by the applicable state board. This plan demonstrates that Missouri meets the Section 128 requirements via the referencing of specific corresponding state statutes and regulations.

Date EPA Approval Document

MACC Adoption:
July 2012

Federally Approved
78 FR 37461

Revision to Section 128 Declaration: Missouri Air Conservation Commission

All states were required by the Clean Air Act to submit Regional Haze SIPs in order to address visibility in Class I areas.  This SIP addresses pollutants that affect visibility and also those that cause acid rain.

Date EPA Approval Document

July 2017

  Clarification letter to EPA regarding the state’s reliance on CSAPR to meet BART requirements
August 2014
Federal Approval:
80 FR 58410
State of Missouri Regional Haze Plan 5-Year Progress Report
MACC Adoption:
June 2009
Federal Limited Approval:
77 FR 38007

Section 110(a)(2)(D)(i)(l) of the Clean Air Act requires states to submit SIPs demonstrating that emissions in their state do not have a significant impact on downwind states’ ability to meet or maintain the National Ambient Air Quality Standards for all criteria pollutants. Typically, ozone and particulate matter are the two criteria pollutants in which long range transport of pollutants and precursors can have a significant impact on downwind states.

Date EPA Approval Document
MACC Adoption:
March 2015
Federally Approved Plan:
80 FR 51131

Cross-State Air Pollution Rule (CSAPR) NOx Annual Trading Program
Cross-State Air Pollution Rule (CSAPR) NOx Ozone Season Trading Program

Note: The two CSAPR SIPs listed above reallocated CSAPR allowances for the 2016 control period.  The department has also submitted SIPs, via three state rules, to reallocate CSAPR allowances for the control periods in 2017 and beyond, and they are codified in the Missouri CSR: 10 CSR 10-6.372, 10 CSR 10-6.374, and 10 CSR 10-6.376.  These rules can be viewed at Missouri’s Secretary of State Website.

MACC Adoption:
April 2005
Federally Approved Plan

NOx SIP Call

When new or revised NAAQS are published the EPA also releases implementation requirements for those new standards that must be included in SIPs. The Inspection/Maintenance Program (I/M) is required by ozone implementation rules for all moderate ozone non-attainment areas. This SIP defines the passenger vehicle emission inspection requirements for vehicles registered within the St. Louis ozone non-attainment area. See Gateway Vehicle Inspection Program for more information.


EPA Approval


MACC Adoption: October 2019


Inspection and Maintenance Program for the St. Louis Area – 2019 Revision

MACC Adoption: December 2007 Federally Approved Plan:
80 FR 11323

2007 Revision of the SIP for the Inspection and Maintenance Program for the St. Louis 1997 8-Hour Ozone Nonattainment Area

MACC Adoption: October 2003

Federally Approved Plan:
69 FR 51953

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