June 30, 2016 - This draft guidance document was prepared by the EPA to assist states in developing and submitting regional haze State Implementation Plans for the second implementation period (2018-2028). This document is currently in draft form, and the EPA plans to finalize the guidance after the public comment period. The availability of this draft guidance and the details of the public comment period are announced in the Notice of Availability. A summary of the purpose and content of the document is given in the fact sheet.

December 20, 2018 - EPA's Technical Guidance on Tracking Visibility Progress for the Second Implementation Period of the Regional Haze Program provides final EPA guidance on topics addressed in section 5 of the 2016 draft guidance.

• Regional Haze Guidance Technical Support Document and Data File
• Notice of Availability of Draft Guidance on Regional Haze (81 FR 44608)

August 20, 2019 - EPA issued Final Guidance on Regional Haze State Implementation Plans for the Second Implementation Period (PDF)(87 pp, 821 K). EPA considered public comments on the 2016 Draft Guidance, linked below, in the development of the Final 2019 Guidance, which is intended to assist states as they develop plans to address visibility impairment for the second implementation period under EPA's Regional Haze Rule.

• Draft Guidance for the Second Implementation Period of the Regional Haze Rule (PDF)(248 pp, 3 MB)
• Fact Sheet for Draft Regional Haze Guidance (PDF)(3 pp, 128 K)