Nasal airflow and trans-nasal pressure difference was measured by active anterior rhinomanometry in 24 subjects. An analysis was undertaken to determine the 'goodness of fit' of two models used to characterize nasal airflow, one model by Broms and the other by O'Neill and Tolley. A judicious approach to choice of fit criterion led to the conclusion that the latter model provided a more accurate characterization of nasal airflow. Additionally this model may be useful to quantify alar valve stiffness. A portable computerized system incorporating the use of the model has been developed and is currently in use.