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Technical Correction to the National Ambient Air Quality Standards for Particulate Matter (Final)
Mar. 20, 2017
EPA is taking final action to make a technical correction to equation 2 in appendix N to part 50, section 4.4(b) of the National Ambient Air Quality Standards (NAAQS) for Particulate Matter. Equation 2 in appendix N describes an intermediate step in the calculation of the design value for the annual PM2.5 (particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers) NAAQS. This action corrects Equation 2 to properly account for cases where a site has quarters without daily values and passes the minimum quarterly value data substitution test. This change accurately reflects the intended calculation of the annual PM2.5 design value and is consistent with the text of section 4.1 in appendix N to part 50. This final rule is effective on 19 May 2017. POC is Mr. Brett Gantt, Office of Air Quality Planning and Standards, Air Quality Assessment Division, Air Quality
Analysis Group (Mail Code: C304-04), EPA, 109 T.W. Alexander Drive, Research Triangle Park, NC 27711; tel: 919-541-5274; email: gantt.brett@epa.gov (Federal Register, 20 March 2017 [Rules and Regulations], pages 14325-14327).

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Last Updated: January 22, 2018