# Technical Correction to the National Ambient Air Quality Standards for Particulate Matter
> **Rule** · Direct final rule. · Published 2016-08-11 · Effective 2016-10-11 · 81 FR 53006
## Document
- **Document number:** 2016-19034
- **Category:** air-emissions
- **Federal Register citation:** 81 FR 53006
- **CFR reference:** 40 CFR 50
- **Publication date:** 2016-08-11
- **Effective date:** 2016-10-11
- **EPA docket:** EPA-HQ-OAR-2016-0408
## Abstract

The Environmental Protection Agency (EPA) is taking direct final action to make a technical correction to an equation in an appendix in the National Ambient Air Quality Standards (NAAQS) for Particle Pollution. Equation 2 describes an intermediate step in the calculation of the design value for the annual PM<INF>2.5</INF> (particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers) NAAQS. This action corrects a scrivener's error in one of the equations used to calculate an annual mean PM<INF>2.5</INF> concentration, to properly account for cases where a site does not have four complete quarters of data and passes one of two substitution tests. This change accurately reflects the intended calculation of the annual mean PM<INF>2.5</INF> design value and is consistent with the text elsewhere in the appendix.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2016/08/11/2016-19034/technical-correction-to-the-national-ambient-air-quality-standards-for-particulate-matter)
---
*AI Analytics · CC0 1.0*