To measure the relationship between gas exchange rates and diffusion resistance, and their changes in time, both should be measured on the same fruit or vegetable, because diffusion resistance shows large variations between individuals of the same species and cultivar. The method described enables this simultaneous measurement, under various gas conditions, without influencing the product. Neon (Ne) was used as a tracker. Its concentration was brought to 110 Pa after closing a flask containing an apple kept at a specific gas condition. Changes in oxygen and carbon dioxide concentration were used to calculate gas diffusion resistance. The method enables assessment of important physiological data by a simple extension of standard gas exchange measurements. One benefit of using Ne instead of ethane, in addition to a possible influence of ethylene concentrations on ethane measurements, is that ethane production is found in ageing plant tissues.