Turbulent transports in hydrogen-air flame are investigated by introducing relevant scalar variables which allow for identification and separate processing of density effects induced by both mixing and reactive processes. The algebraic proposed models for the turbulent scalar flux and the turbulent kinetic energy allow to recover and generalise well-known previously established relations and highlight the possible occurrence of counter-gradient turbulent diffusion. The calculation of a practical turbulent diffusion hydrogen-air flame is also performed and exhibits a strong production of turbulence near stoichiometric conditions.