eCFR Reference Browser

---

title: "40 CFR §63.3"

source: "https://www.ecfr.gov/current/title-40/section-63.3"

title_number: "40"

volume_number: "11"

chapter_number: "Unknown"

subchapter_code: "C"

subchapter_subject: "AIR PROGRAMS (CONTINUED)"

part_code: "63"

part_subject: "NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES"

subpart_code: "A"

subpart_subject: "General Provisions"

section_number: "63.3"

section_subject: "Units and abbreviations."

cfr_reference: "40 CFR 63.3"

title_name: "Title 40"

title_subject: "Protection of Environment"

parts_covered: "Part 63 (§§ 63.1 to 63.599)"

revised_date: "Revised as of July 1, 2019"

publication_date: "As of July 1, 2019"

contains_description: "Containing a codification of documents of general applicability and future effect"

publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"

---

Used in this part are abbreviations and symbols of units of measure. These are defined as follows:

(a)System International (SI) units of measure:

(b)Other units of measure:

(c)Miscellaneous:

§63.3 - Units and abbreviations.