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Ground-level Ozone Pollution

Fact Sheet - Managing Ozone Air Quality: Actions on 1997 Ozone NAAQS State Implementation Plans


  • On April 29, 2009, the U.S. Environmental Protection Agency (EPA) signed seven Federal Register (FR) notices taking two separate types of action on State 1997 8-hour ozone nonattainment planning requirements. 
  • In six separate notices, EPA is proposing to disapprove seven ozone attainment demonstrations and, in one additional notice, EPA is making two findings of failure to submit ozone attainment demonstrations.
  • EPA is proposing disapprovals for the ozone attainment demonstration element of the State Implementation Plans (SIPs) for following five states:
    • Connecticut for their portion of the New York City ozone nonattainment area
    • New Jersey for their portion of the New York City ozone nonattainment area
    • New Jersey for their portion of the Philadelphia ozone nonattainment area
    • Delaware for their portion of the Philadelphia ozone nonattainment area
    • Pennsylvania for their portion of the Philadelphia ozone nonattainment area
    • Maryland for their portion of the Philadelphia ozone nonattainment area
    • Maryland for the Baltimore ozone nonattainment area
  • EPA is proposing to find that these areas are not projected to attain the 1997 8-hour ozone standard by the date required under the Clean Air Act.  The proposed disapprovals are based on EPA’s review of air quality data, which indicates that these areas will be unable to meet the latest moderate area attainment date of June 2010.
  • The State of New York is not included on the disapproval list because they requested a higher nonattainment classification for the New York City nonattainment area. A higher reclassification would change the attainment date to June 2013. The state concluded that the air quality data and the modeling in their SIP did not show attainment by the June 2010 attainment date. At this time, the multi-state New York City ozone nonattainment area cannot be reclassified until Connecticut and New Jersey also request the higher classification.
  • EPA is also making a finding that North Carolina and South Carolina missed the June 15, 2007 Clean Air Act deadline for submitting ozone attainment demonstrations for the Charlotte ozone nonattainment area. This was a deadline for submitting complete SIPs showing how they will meet the 1997 ozone standard; it was not a deadline for meeting the standard.
    • North Carolina and South Carolina originally submitted the required attainment demonstrations, but then opted to withdraw their submissions.
  • For findings of failure to submit, the Clean Air Act requires EPA to start three timetables, known as clocks, on the date the finding is published in the Federal Register. For proposed disapprovals, these clocks will not start until EPA issues a final disapproval action.
    • EPA will accept public comment for 30 days on the proposed action and then take final action.
  • The three clocks include two sanctions clocks, and a deadline for EPA to issue federal implementation plans (FIPs). These clocks range from 18 months to two years.
  • EPA is working with these States to ensure they submit revised and approvable plans as soon as possible.
  • For the findings for failure to submit, the sanction clocks will be turned off when the States submit a complete ozone attainment demonstration SIP; the FIP clock will be turned off when EPA approves a final SIP. For disapprovals, the sanction and FIP clocks will be turned off when an EPA approved ozone attainment demonstration SIP becomes effective.
  • The Clocks
  • Emission offset sanctions (18 months): Under emission offset sanctions, a state must ensure that each ton of emissions created by a new stationary source of pollution is offset by a two ton reduction in existing stationary sources. These offset requirements would apply in areas designated as “nonattainment” for the ozone standard.
  • Highway fund sanctions (two years): Under highway fund sanctions, a state can lose funding for transportation projects if the funds have not been obligated by the Federal Highway Administration by the date the highway sanctions are imposed.  (Projects that have already received approval to proceed and had funds obligated may proceed.)
  • Federal Implementation Plans (two years): Under a FIP, EPA, not the state, determines what steps must be taken to meet the standard.  


  • Ground-level ozone forms when emissions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) “cook” in the sun. Ozone exposure is linked to acute respiratory problems, aggravated asthma, reduced lung capacity, inflamed lung tissue, and impairment of the body’s immune system.
  • SIPs include a number of documents and programs designed to address ground level ozone pollution.  These actions apply to the attainment demonstration due on June 15, 2007.
  • The attainment demonstration requires states with nonattainment areas to analyze the potential of those areas to meet the 1997 ozone standard.  The state uses air quality models and other relevant technical information to demonstrate its ability to achieve the air quality standard by a certain date.  For these disapprovals, EPA has determined that these areas will not be able to achieve the air quality standard by June 2010.
  • These actions were originally signed in January 2009.  The new EPA leadership reviewed them as part of a regulatory review initiated by the White House.
  • North and South Carolina originally submitted an attainment demonstration, but then opted to withdraw their submissions.  For these two states, EPA is making a finding of failure to submit.


For further information concerning this action, contact Mr. Butch Stackhouse of EPAs Office of Air Quality Planning and Standards at (919) 541-5208 or by email at