This paper investigates dried earth, straw fibers, and pre-mixed earth, determining CO2 emission factors for the product stage based on surveys of nine producers in Japan. Since these producers are small-scale and rely on local sourcing, emissions from A1 and A2 are minimal; most emissions originate in A3, where higher quality requirements reduce production efficiency and increase emission factors. Emissions per unit mass range from 6.09×10-3 to 1.01×10-1, 4.80×10-2 to 3.06×10-1, and 7.73×10-3 to 2.88×10-2 kg-CO2/kg, respectively. These factors provide essential foundational data for the Life Cycle Assessment of earthen architecture.
Morishita et al. (Sun,) studied this question.