40 CFR § 96.303 - Measurements, abbreviations, and acronyms.

---
identifier: "/us/cfr/t40/s96.303"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 96.303 - Measurements, abbreviations, and acronyms."
title_number: 40
title_name: "Protection of Environment"
section_number: "96.303"
section_name: "Measurements, abbreviations, and acronyms."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "96"
part_name: "NOX BUDGET TRADING PROGRAM AND CAIR NOX AND SO2 TRADING PROGRAMS FOR STATE IMPLEMENTATION PLANS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401, 7403, 7410, 7601, and 7651,"
regulatory_source: "63 FR 57514, Oct. 27, 1998, unless otherwise noted."
cfr_part: "96"
---


# 96.303 Measurements, abbreviations, and acronyms.

Measurements, abbreviations, and acronyms used in this subpart and subparts BBBB through IIII are defined as follows:

Btu—British thermal unit

CO<sub>2</sub>—carbon dioxide

H<sub>2</sub>O—water

Hg—mercury

hr—hour

kW—kilowatt electrical

kWh—kilowatt hour

lb—pound

mmBtu—million Btu

MWe—megawatt electrical

MWh—megawatt hour

NO<sub>X</sub>—nitrogen oxides

O<sub>2</sub>—oxygen

ppm—parts per million

scfh—standard cubic feet per hour

SO<sub>2</sub>—sulfur dioxide

yr—year

[71 FR 25392, Apr. 28, 2006]