Regulations last checked for updates: Jan 30, 2025

Title 40 - Protection of Environment last revised: Nov 08, 2025
§ 98.528 - Definitions.

All terms used of this subpart have the same meaning given in the Clean Air Act and subpart A of this part.

Table 1 to Subpart ZZ of Part 98—CO2 Emission Factors for Carbonate-Based Raw Materials

Carbonate Mineral name(s) CO2 emission
factor a
BaCO3Witherite, Barium carbonate0.223
CaCO3Limestone, Calcium Carbonate, Calcite, Aragonite0.440
Ca(Fe,Mg,Mn)(CO3)2Ankerite b0.408-0.476
CaMg(CO3)2Dolomite0.477
FeCO3Siderite0.380
K2CO3Potassium carbonate0.318
Li2CO3Lithium carbonate0.596
MgCO3Magnesite0.522
MnCO3Rhodochrosite0.383
Na2CO3Sodium carbonate, Soda ash0.415
SrCO3Strontium carbonate, Strontianite0.298

a Emission factors are in units of metric tons of CO2 emitted per metric ton of carbonate-based material.

b Ankerite emission factors are based on a formula weight range that assumes Fe, Mg, and Mn are present in amounts of at least 1.0 percent.

source: 74 FR 56374, Oct. 30, 2009, unless otherwise noted.
cite as: 40 CFR 98.528