SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

SIP Approval: Arkansas (revisions to regional haze rules for electric generating units).

EPA announced the availability of and seeks comment on its draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft), which in conjunction with other assessments provides the scientific basis for EPA's decisions on the adequacy of the current review of ozone NAAQS and the appropriateness of possible alternative standards.

EPA announced the availability of and seeks comment on its draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft), which in conjunction with other assessments provides the scientific basis for EPA's decisions on the adequacy of the current review of ozone NAAQS and the appropriateness of possible alternative standards.

EPA announced the availability of and seeks comment on its draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft), which in conjunction with other assessments provides the scientific basis for EPA's decisions on the adequacy of the current review of ozone NAAQS and the appropriateness of possible alternative standards.

EPA announced the availability of and seeks comment on its draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants (External Review Draft), which in conjunction with other assessments provides the scientific basis for EPA's decisions on the adequacy of the current review of ozone NAAQS and the appropriateness of possible alternative standards.