A long-term field measurement was performed to investigate turbulent transfer in a densely built-up urban surface layer. The turbulent transfer efficiencies of heat, vapor, and CO<SUB>2</SUB> were examined. In the morning the low-frequency eddies penetrating the entire atmospheric boundary layer transfer water vapor efficiently due to the entrainment of dry air from upper to the surface. M.O.S. theory predicts that relative transfer efficiencies are unity and have no dependency on stability. But ratios for vapor/heat and CO<SUB>2</SUB>/heat observed show that the transfer efficiencies of vapor and CO<SUB>2</SUB> are smaller than heat. This tendency is more significant in unstable condition. In order to discuss this result, wavelet analysis for transfer efficiency of scalars was conducted. The thermal structure and organized structure transfer heat efficiently. Vapor and CO<SUB>2</SUB> are also transferred as well as heat by some structures. But they are not or adversely transferred by other structures. Followings are considered as this reason. (1) Heat is an active scalar and produces the thermal structures by itself. Hence, the heat is transferred most efficiently. Vapor and CO<SUB>2</SUB> are transferred passively and the efficiency is less than heat. (2) The absorption/source of vapor and CO<SUB>2</SUB> is inhomogeneous. As a result, the heterogeneity of vapor and CO<SUB>2</SUB> concentration distribution causes their transfer efficiency lower.