Decision of main variable of Tier 2 : CH4 emission factor and CH4 generation rate constant Landfill CH4 emission factor(L 0 ) CH4 emission factor(L 0 )(ton-TCE/ton-Waste) CH4 emission velocity constant (k : yr -1 ) (k : yr -1 ) Note 1 time 2 times Average 1 time 2 times Average Ulsan city, Sung-am Dong 0.33540.32530.33040.07040.03100.0507 Kyong-gi province, Yong-in city 0.39850.30380.35120.02780.02720.0275 Choong-nam province, Bo- ryung city 0.11880.072680.095740.04310.04160.0424 Choong-book province, Jae- chun city 0.10150.095550.09852 Insufficient landfill record data Choong-nam province, Chun-an city 0.33960.28040.31000.06320.07310.0682