Chemical transfer between environmental compartments plays a key role in an adequate command and control of pollutants. The gas-liquid partitioning equilibrium constant, better known as the Henry's constant (K H) represents a crucial parameter in order to determine the environmental fate of chemicals and therefore, an accurate determination at ambient conditions is extremely important to assess the mentioned process. Within the experimental dynamic methods, the batch air stripping technique (BAS) has as major drawback the equilibrium condition among phases, which is hardly achieved in open natural systems. The present work, based on previously published mathematical models (4, 22), centers in the development of a new mathematical approach to determine K H by means of the BAS in non-equilibrium conditions through experimental and theoretical determinations of volumetric mass transfer coefficients (K La) for volatile (1,1-DCE, ethylbenzene, p-xylene and toluene) and semivolatile (1,1,2-TCE, 1,2-DCP, penhylmethylether (anisole) and naphthalene) organic compounds of environmental concern. In order to validate the approach, values obtained were compared to the K H determined through the static EPICS (Equilibrium Partitioning in Closed Systems) method, confirming the calculated K H and ratifying the new approach