The detailed analysis of an environmental system is a prerequisite to efficient monitoring design. Such analysis includes the sampling scheme, field measurements, pathway analysis and exposure response. The exposure commitment method rationally ties these aspects together, allowing one to look at the system as a whole rather than at the separate parts. Monitoring data acquired as part of a field project to develop a pollutant monitoring system for biosphere reserves are analysed. The field study took place in the autumn of 1977 and spring of 1978 in the Great Smoky Mountains National Park, a designated biosphere reserve site in the U.S.A. A multi-media integrated sampling programme was carried out with a variety of samples collected, including soil, litter, vegetation, water and air. in this report, a kinetic model of this forest ecosystem is developed. Values for compartment sizes and rate constants are determined from the literature. Inputs to the system are from measured values. The model results show good agreement with the measured field results. The steady-state concentrations are used to estimate the transfer coefficients for the exposure commitment analysis. The use of transfer coefficients to compute contributions to steady-state concen- trations or to determine exposure commitments is illustrated. It is shown that the exposure commitment method is a useful means of analysing an environmental system and of contributing to the design of monitoring programmes.