The Clean Air Act regulates particulate matter as a criteria pollutant. The U.S. Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards for both fine and course particulate matter (PM). These standards include both primary standards to protect public health and secondary standards to protect the environment. EPA reviews pollutant standards every five years. Sometimes, a review results in a tightened standard.
The particulate matter standards below include the state implementation plan elements developed for each of the standards and the relevant documents associated with the boundary designations. If you are looking for a document that is not available on our website, please submit a Open Records/ Sunshine Law Request.
Fine Particulate Matter (PM2.5)
Fine particulate matter (PM2.5) includes particles that are smaller than 2.5 microns in size. The standards for PM2.5 included an annual standard and a 24-hour standard. The annual standard was set in 1997, to 15 micrograms per cubic meter of air (µg/m3). The 24-hour standard was set in 2006, to 35 µg/m3. On Dec. 14, 2012, EPA revised the standard for PM2.5. The 24-hour standard was retained, but the annual standard was lowered from 15 µg/m3 to 12 µg/m3.
- 2023 Standard
2023 Standard Actions
MoDNR Submittal Date MoDNR Action/ Document EPA Date EPA Action/ Document March 23, 2023 MoDNR Comment Letter on Federal Register Action: Reconsideration of the National Ambient Air Quality Standards for Particulate Matter Jan. 27, 2023 Reconsideration of the National Ambient Air Quality Standards for Particulate Matter [88 FR 5558] - 2012 Standard
Annual PM2.5 Standard = 12 µg/m3
2012 Standard Boundary Recommendations Actions
MoDNR Submittal Date MoDNR Action/ Document EPA Date EPA Action/ Document Oct. 28, 2014 MoDNR Response to EPA Letter Regarding Designations for the 2012 Annual Fine Particulate Matter National Ambient Air Quality Standard Jan. 1, 2015 Air Quality Designations for the 2012 Primary Annual Fine Particle (PM2.5) National Ambient Air Quality Standards (NAAQS) [80 FR 2206]
Effective: April 15, 2015Dec. 10, 2013 Missouri's Recommendation for the Area Boundary Designations for the 2012 Annual Fine Particulate Matter National Ambient Air Quality Standard Aug. 19, 2014 EPA Response to Recommendations on 2012 Revised Primary Annual Fine Particle (PM2.5) National Ambient Air Quality Standards - 120-day letter for the standard 2012 Standard Infrastructure SIP Actions
2012 Standard St. Louis Actions
MoDNR Submittal Date MoDNR Action/Document EPA Date EPA Action/Document Dec. 10, 2018 Redesignation Request for the Missouri Portion of the St. Louis Unclassifiable Area for the 2012 Annual Fine Particulate Matter Standard July 29, 2019 Approval of Missouri Air Quality Implementation Plans; Redesignation of the Missouri Portion of the St. Louis-St. Charles-Farmington, MO-IL 2012 PM2.5 Unclassifiable Area [84 FR 36742]
Effective: April 15, 2015- 2006 Standard
24-hour PM2.5 Standard = 35 µg/m3
2006 Standard Boundary Recommendations Actions
MoDNR Submittal Date MoDNR Action/Document EPA Date EPA Action/Document Oct. 2008 MoDNR Response to EPA Letter Regarding Designation of Areas for the 24-hour Particulate Matter 2.5 National Ambient Air Quality Standard Nov. 13, 2009 Air Quality Designations for the 2006 24-Hour Fine Particle (PM2.5) National Ambient Air Quality Standards [74 FR 58688]
Effective: Dec. 14, 2009Dec. 6, 2007 2006 Fine Particle (PM2.5) Boundary Recommendation and Technical Support Document Aug. 18, 2008 EPA Intent to Modify Recommendation for Particulate Matter 2.5 Area Designation as Nonattainment - 120-day letter 2006 Standard Infrastructure Actions
MoDNR Submittal Date MoDNR Action/Document EPA Date EPA Action/Document Aug. 27, 2009 Missouri Plan for Implementation, Maintenance and Enforcement of [2006 Particulate Matter 2.5] National Ambient Air Quality Standards June 21, 2013 Approval and Promulgation of Implementation Plans; State of Missouri; Infrastructure SIP Requirements for the 1997 and 2006 Fine Particulate Matter National Ambient Air Quality Standards [78 FR 37457] - 1997 Standard
Annual PM2.5 Standard = 15 µg/m3
1997 Standard Boundary Recommendations Actions
MoDNR Submittal Date MoDNR Action/Document EPA Date EPA Action/Document March 8, 2004 1997 Fine Particle (PM2.5) Boundary Recommendation and Technical Support Document Jan. 5, 2005 Air Quality Designations and Classifications for the Fine Particles (PM2.5) National Ambient Air Quality Standards [70 FR 944]
Effective: April 5, 2005June 29, 2004 EPA Response to 1997 Fine Particle (PM2.5) Boundary Recommendation - 120-day letter 1997 Standard Infrastructure Actions
1997 Standard St. Louis Actions
Coarse Particulate Matter (PM10)
Course particulate matter (PM10) includes PM2.5 and also coarser particles between 2.5 and 10 microns in size. EPA established the most current standard for PM10 in 2006. The standard is based on the 24-hour average concentrations set at 150 µg/m3.
- 2006 Standard
24-hr PM10 Standard = 150 µg/m3
2006 Standard Carthage Actions
MoDNR Submittal Date MoDNR Action/Document EPA Date EPA Action/Document May 29, 2014 Americold Logistics, LLC 24-Hour Particulate Matter (PM10) National Ambient Air Quality Standard (NAAQS) Consent Judgment Jan. 28, 2016 Approval of Missouri’s Air Quality Implementation Plans; Americold Logistics, LLC 24-Hour Particulate Matter (PM10) National Ambient Air Quality Standard (NAAQS) Consent Judgment [80 FR 4888]