On or about May 23, 2022, the Environmental Protection Agency (EPA) will make available the document, Policy Assessment for the Reconsideration of the National Ambient Air Quality Standards for Particulate Matter (PA). This document was prepared as a part of the current reconsideration of the 2020 final decision on the National Ambient Air Quality Standards (NAAQS) for Particulate Matter (PM). The PA serves to “bridge the gap” between the currently available scientific and technical information and the judgments required of the Administrator in determining whether to retain or revise the existing PM NAAQS.

Read more > https://www.federalregister.gov/documents/2022/05/26/2022-10972/release-of-the-policy-assessment-for-the-reconsideration-of-the-national-ambient-air-quality