40 CFR § 1031.200 - Abbreviations.

---
identifier: "/us/cfr/t40/s1031.200"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 1031.200 - Abbreviations."
title_number: 40
title_name: "Protection of Environment"
section_number: "1031.200"
section_name: "Abbreviations."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "U"
subchapter_name: "AIR POLLUTION CONTROLS"
part_number: "1031"
part_name: "CONTROL OF AIR POLLUTION FROM AIRCRAFT ENGINES"
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. 7401-7671q."
regulatory_source: "87 FR 72351, Nov. 23, 2022, unless otherwise noted."
cfr_part: "1031"
---


# 1031.200 Abbreviations.

This part uses the following abbreviations:

Table 1 to § 1031.200—Abbreviations

|  |  |
| --- | --- |
| ° | degree |
| % | percent |
| CO | carbon monoxide |
| CO | carbon dioxide |
| EI | emission index |
| g | gram |
| HC | hydrocarbon(s) |
| kg | kilogram |
| kN | kilonewton |
| kW | kilowatt |
| LTO | landing and takeoff |
| m | meter |
| mg | milligram |
| µg | Microgram |
| NO | oxides of nitrogen |
| Num | number |
| nvPM | non-volatile particulate matter |
| nvPM | non-volatile particulate matter mass |
| nvPM | non-volatile particulate matter number |
| nvPM | non-volatile particulate matter mass concentration |
| rO | rated output |
| rPR | rated pressure ratio |
| SN | smoke number |