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Title 40

Displaying title 40, up to date as of 6/12/2026. Title 40 was last amended 6/11/2026.
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§ 97.703 Measurements, abbreviations, and acronyms.

Measurements, abbreviations, and acronyms used in this subpart are defined as follows:

Btu—British thermal unit

CO2—carbon dioxide

CSAPR—Cross-State Air Pollution Rule

H2O—water

hr—hour

kWh—kilowatt-hour

lb—pound

mmBtu—million Btu

MWe—megawatt electrical

MWh—megawatt-hour

NOX—nitrogen oxides

O2—oxygen

ppm—parts per million

scfh—standard cubic feet per hour

SIP—State implementation plan

SO2—sulfur dioxide

TR—Transport Rule

yr—year

[76 FR 48458, Aug. 8, 2011, as amended at 81 FR 74619, Oct. 26, 2016]