This is a Notice of Availability and public comment period for Volumes 1 and 2 of the Integrated Review Plan (IRP) for the National Ambient Air Quality Standards for Ozone and Related Photochemical Oxidants, released by EPA on December 20, 2024. Volume 1 provides background on the air quality criteria and O3 NAAQS; Volume 2 identifies policy-relevant issues and describes key considerations for developing the Integrated Science Assessment (ISA). This is a planning-phase document, not a NEPA environmental review; it does not analyze project-level environmental impacts. Public comments on Volume 2 are due by January 21, 2025.1