The aim of the research was to investigate the magnitudes of the losses of some volatile organic compounds from the solid adsorbents, Carbotrap and Chromosorb 106 due to back diffusion during long-term diffusive sampling of volatile organic compounds in the environment. Experiments were performed by loading the compounds to be tested on the adsorbent tubes and leaving them in an outdoor environment to simulate the rear life sampling conditions over a 14 day period. The losses due to back diffusion were investigated for both the high and the low initial concentrations of the fourteen compounds covering a wide range of volatilies namely acetone, dichloromethane, pentane, hexane, benzene, heptane, toluene, octane, ethylbenzene, m- xylene, o- xylene, nonane, decane and undecane.