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On January 6, 2010, EPA proposed to further lower the 8-hour primary ozone standard from 0.075 ppm, set in 2008, to a level within the range of 0.060 - 0.070 ppm to protect public health. EPA is also proposing a new cumulative, seasonal secondary standard, to protect sensitive vegetation and ecosystems, within the range of 7-15 ppm-hours. Because the 2008 standards were not as restrictive as was recommended by the Clean Air Scientific Committee (CASAC), EPA elected to reconsider the standards and follow CASAC's recommendations. Once the standards are published in the Federal Register, EPA will accept public comment for 60 days. Public hearings will be held on February 2 in Houston and Arlington, Virginia and on February 4 in Sacramento. According to EPA, it expects to issue final standards by August 31, 2010 and pursue an implementation schedule as follows:

  • By January 2011 - States make recommendations for areas to be designated attainment, nonattainment or unclassifiable
  • By July 2011 - EPA makes final area designations
  •  August 2011 - Designations become effective
  • December 2013 - State Implementation Plans, outlining how states will reduce pollution to meet the standards, are due to EPA
  • 2014 to 2031 - States are required to meet the primary standard, with deadlines depending on the non-attainment status

No new monitoring requirements are proposed in this action although ozone monitoring network design changes were proposed in July 2009 that would support the proposed standards. EPA expects to finalize the proposed changes along with the final standards in August 2010.

Under the current 8-hr ozone standard, the following counties are nonattainment in Texas:






Fort Bend















Under the proposed 2008 ozone standard level of 0.075 ppm the counties below were recommended by the Governor to EPA on March 9, 2009 for reclassification to ozone nonattainment status.





 El Paso




With the lowering of this standard to levels within the range of 0.060 - 0.070 ppm, other counties may now be identified by the TCEQ as nonattainment including those counties that had previously been proposed for reclassification under the 2008 standard, but which were removed from final recommendation by the Governor for various reasons. These counties include:










 El Paso







Once the standard is final, TCEQ will propose counties for nonattainment under the new 2010 ozone standard. A public comment period is expected during which counties, sites, or any individual from the public can provide input regarding the proposed redesignations prior to Texas making its final recommendations to the EPA in January 2011.

There are eleven factors that are considered when setting ozone nonattainment boundaries. Trinity can assist in preparing an eleven factor analysis documenting why a county should not be included in a proposed nonattainment area, which can be submitted to TCEQ. Trinity has prepared eleven factor analyses and ozone SIP information for clients across the U.S. and has testified before TCEQ Commissioners and the State Senate Environmental Subcommittee on proposed ozone control strategies. If you are interested in determining if this type of analysis could benefit your operations and/or county for proposed Ozone and/or PM2.5 nonattainment reclassifications, please contact Trinity at 800-613-9350.