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

Btu—British thermal unit.CO2—carbon dioxide.H2O—water.Hg—mercury.hr—hour.kW—kilowatt electrical.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.SO2—sulfur dioxide.yr—year.