Regional Effort

The SA-BC MPO study area currently has several Continuous Air Quality Monitoring Systems (CAMS) that record ozone levels daily. EPA utilizes a three-year rolling average to determine our air quality status.  The regulatory ozone CAMS include the San Antonio Northwest (C23), Camp Bullis (C58), Calaveras Lake (C59), CPS Pecan Valley (C678) and the CPS Heritage Middle School (C622). In addition, the Alamo Area Council of Governments (AACOG) operates six non-regulatory ozone monitoring sites across the region during the ozone season.

In order to remain in attainment, the area will need a 2007-2009 three-year, fourth highest annual average of no greater than 75 parts per billion (ppb) This is the National Ambient Air Quality Standard (NAAQS) for 8-hour ozone concentrations.  Currently, the San Antonio Northwest monitor (C23) is the most important monitor as it has recorded the highest readings during this time period.  The fourth highest reading was 71 ppb in 2007, 78 ppb in 2008 and as of August 28th, it was 75 ppb for 2009. Therefore, this year, C23 must not have an additional 8-hour ozone reading of greater than 76 ppb for the area to stay in attainment.

- UPDATE -

With the 2009 ozone season winding down, we are still in attainment under the new standard.

However, recently there have been new developments with regard to this 2008 standard.

Since the release of the 2008 Ozone Standard, it has been subject to legal challenges from both sides - those who hope to make it more stringent and those seeking relief from it. While the lower standard of 75 ppb will yield more public health benefits, it was not set as low as EPA’s scientific advisors had recommended. Since the Clean Air Act makes science the preeminent criterion in the standard setting process, many who felt it should be lower did not believe that EPA followed the Act correctly in revising the standard.

In 2009, the Justice Department asked a federal court to refrain from hearing arguments for 180 days “to give the Obama administration an opportunity to determine whether the standards ‘should be maintained, modified or otherwise reconsidered.’ ” On September 16, 2009, the EPA announced the agency would “reconsider” the 2008 national ozone standard to ensure they are scientifically sound and protective of human health.

According to EPA, the agency will conduct a thorough review of the science that guided the 2008 decision, including more than 1,700 scientific studies and any public comments from that rulemaking process. The Agency will also review the findings of EPA’s independent Clean Air Scientific Advisory Committee, which recommended stronger smog standards.

EPA has stated that it will move quickly to implement any new standards that might result from the reconsideration. To reduce the workload for states during the interim period of reconsideration, the agency will propose to stay the 2008 standards for the purpose of attainment and nonattainment area designations. EPA has noted that it will work with states, local governments and tribes to ensure that air quality is protected during that time.

Originally, designations under the 2008 Ozone Standard would have been made in March 2010, with transportation conformity due within on year from that date.  Now, EPA has stated that it will propose revisions to the ozone standards by December 2009 and will issue a final decision by August 2010.  Final designations will be made in August of 2011 with transportation conformity due a year from that date. Therefore, the designation process has been delayed for those who may fail the 2008 Ozone Standard this year. 

For additional information visit:

• Clean Air Plan
• Alamo Area Council of Governments (AACOG)
• San Antonio Early Action Compact (EAC) Area (EPAs Site)