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Implementation Plans

This web page provides links to recent State Implementation Plan (SIP) submissions that Iowa has made to EPA. The web page includes links to information about recent Iowa designation recommendations for National Ambient Air Quality Standards (NAAQs) that were promulgated or revised starting in 2006.

Questions about the information on this web page may be directed to Jim McGraw at 515-725-9543 or

Comments on Proposed NAAQS

2015 Ozone

On December 17, 2014, EPA published a proposal to make revisions to the primary and secondary National Ambient Air Quality Standards (NAAQS) for ozone. DNR submitted comments to EPA regarding the proposal on March 16, 2015.

Designation Recommendations

The Clean Air Act requires the state to submit designation recommendations to EPA within one year of any NAAQS revision. EPA is responsible for issuing the final designations. EPA's final designations can be found in 40 CFR Part 81.
2012 PM2.5
2010 NO2
2010 SO2 (Includes Muscatine 1-hour SO2 Nonattainment Area)
2008 Lead (Includes Council Bluffs Lead Nonattainment Area)
2008 Ozone
2006 PM2.5

Implementation Plans for Nonattainment Areas

Iowa currently has two areas that have been designated as not meeting (nonattainment) the National Ambient Air Quality Standards. These areas are in Council Bluffs (lead nonattainment) and Muscatine (1-hour sulfur dioxide (SO2) nonattainment).
Council Bluffs Lead Nonattainment Area
Muscatine 1-hour SO2 Nonattainment Area

Muscatine PM2.5 SIP Revision

Muscatine PM2.5 SIP Revision

On February 18, 2014, the Environmental Protection Commission approved a revision to the State Implementation Plan (SIP) to prevent future violations of the 24-hour fine particulate (PM2.5) National Ambient Air Quality Standards (NAAQS) in Muscatine. The SIP revision was forwarded to U.S. EPA on February 18th for federal notice and approval. EPA approved the SIP revision on December 1, 2014.

Supporting Documents

Implementation Plans for New or Revised NAAQS

The state is required under the Clean Air Act to develop State Implementation Plans (SIPs) for new and revised National Ambient Air Quality Standards (NAAQs), referred to as infrastructure SIPs. Infrastructure SIPs demonstrate that the state has the authority and resources to implement a new or revised NAAQS.
2010 NO2 Infrastructure SIP
2010 SO2 Infrastructure SIP
2008 Ozone Infrastructure SIP
2006 PM2.5 Infrastructure SIP

Regional Haze

In 1999, EPA established rules designed to improve visibility at most larger national parks and wilderness areas. The state of Iowa developed a State Implementation Plan (SIP) to help maintain and improve visibility at nearby federally mandated Class 1 areas. The regional haze regulations require the state to periodically review and revise this plan. The next comprehensive regional haze SIP revision is due July 31, 2018.
2013 Regional Haze (5 year Review)
2008 Regional Haze (Initial SIP Submittal)