A fruit ripening room experiences variations in the concentration of three chief gas species that will strongly adsorb in the ZIF sensing elements: ethylene (C Normal conditions. Under normal conditions, C 2 H 4 gas, the hormone responsible for fruit ripening, is ideally maintained at 150 ppm; humidity is kept ≥ 85% RH (relative humidity) to prevent loss of moisture from the fruit; and CO 2 is prevented from surpassing 5 000 ppm (a permissible human exposure limit) by periodic ventilation. Consequently, we model the C 2 H 4 and H 2 O concentration with a Gaussian distribution and the CO 2 concentration, to reflect its periodic build-up due to fruit respiration , with a uniform distribution.