10/27/2014

Overview of proposed changes and solicitat ions of comment included in the draft O 3 NAAQS proposal

 Primary Standard

o Section II.D.5 proposes that the current primary O 3 standard of 0.075 parts per million (ppm) is not adequate to protect public health, and that it should be revised to provide increase d public health protection.

 Solicits comment on retaining the current standard.

o Section II.E.4 proposes to revise standard by sett ing the level to within the range of 0.065 to 0.070 ppm.

 Solicits comment on alternative standard levels below 0.065 ppm, and as low as 0.060 ppm.

 Secondary Standard

o Section IV.D.3 proposes to revise the current secondary standard to provide increased protection against vegetati on-related effects on public welfare.

 Solicits comments on retaining the cu rrent secondary standard, without revision.

o Section IV.E.5 proposes to revise the level of the current secondary standard to within the range proposed for the primary O 3 standard (0.065 to 0.070 ppm), in order to maintain three-year average W 126 index values at or below 13-17 ppmhrs.

 Solicits comments on setting the level of the secondary standard to maintain three-year average W126 values below 13 ppm-hrs, and as low as 7 ppm-hrs.

 Solicits comments on revising the form of the secondary standard to the W126 index, averaged across three consecu tive years, with a level within the range of 13 ppm-hrs to 17 ppm-hrs.

 Solicits comments on revising the form of the secondary standard to the W126 index, averaged across three c onsecutive years, with a level extending as low as 7 ppm-hrs.

 Air Quality Index (AQI): Section III proposes conforming changes to the AQI for O 3 by setting the AQI value of 100 equal to the level of the 8-hour primary standard, and by making proportional changes to the AQI values of 50, 150, 200 and 300.

 Data Handling: Section V.C proposes several revisions to data handling conventions for O 3 , including a proposed Appendix U that e xplains the computations necessary for determining when the proposed primary and secondary O 3 NAAQS are met at an ambient air quality monitoring site with regard to data selection, reporting, and handling.

 Exceptional Events: Section V.E proposes changes to exce ptional event schedules related to implementing any revised O 3 standards, and proposes to extend the new schedule approach to other future revise d NAAQS and to remove obsolete regulatory language associated with expired exceptional event deadlines for historical standards for O 3 and other NAAQS pollutants.

 O 3 monitoring seasons: Section VI.B proposes changes to the O 3 monitoring seasons.10/27/2014

 Federal Reference Method (FRM): Section VI.D proposes changes to the FRM for monitoring O 3 in the ambient air.

 Photochemical Assessment Monitoring Stations (PAMS) network: Section VI.D proposes changes to the PAMS network design.

 Federal Equivalent Method (FEM): Section VI.E proposes revisions to FEM testing requirements, including making the requirement s for nitrogen dioxide consistent with the requirements for O 3 and removing an obsolete requirement for the annual submission of documentation by manufacturers of cert ain particulate matter monitors.

 Prevention of Signific ant Deterioration (PSD): Section VII.D proposes to add a provision grandfathering certain pending perm its from certain requirements with respect to the proposed revisions to the O 3 NAAQS.