National Ambient Air Quality Standards for Particulate Matter

Document Headings Document headings vary by document type but may contain the following: the agency or agencies that issued and signed a document the number of the CFR title and the number of each part the document amends, proposes to amend, or is directly related to the agency docket number / agency internal file number the RIN which identifies each regulatory action listed in the Unified Agenda of Federal Regulatory and Deregulatory Actions See the Document Drafting Handbook for more details. Environmental Protection Agency 40 CFR Part 50 [EPA-HQ-OAR-2001-0017; FRL-8225-3] RIN 2060-AI44 AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: Based on its review of the air quality criteria and national ambient air quality standards (NAAQS) for particulate matter (PM), EPA is making revisions to the primary and secondary NAAQS for PM to provide increased protection of public health and welfare, respectively. With regard to primary standards for fine particles (generally referring to particles less than or equal to 2.5 micrometers (µm) in diameter, PM 2.5 ), EPA is revising the level of the 24-hour PM 2.5 standard to 35 micrograms per cubic meter (µg/m 3 ) and retaining the level of the annual PM 2.5 standard at 15µg/m 3 . With regard to primary standards for particles generally less than or equal to 10μm in diameter (PM 10 ), EPA is retaining the 24-hour PM 10 and revoking the annual PM 10 standard. With regard to secondary PM standards, EPA is making them identical in all respects to the primary PM standards, as revised. DATES: This final rule is effective on December 18, 2006. ADDRESSES: The EPA has established a docket for this action under Docket ID No. EPA-HQ-OAR-2001-0017. All documents in the docket are listed on the www.regulations.gov Web site. Although listed in the index, some information is not publicly available, e.g. confidential business information or other information whose disclosure is restricted by statute…