This paper proposes a human olfactory interface that modulates airborne odors and enables the users to selectively sniff only the odors that they want. Air containing odors is collected and exposed onto plural types of adsorbents for separation and concentration of odorous substances contained in the odors. The desorbed substances from the adsorbents are mixed at different ratios from the original odors for modulation. This paper describes preliminary work on the evaluation of separation performance of odorous substances in adsorption process. As a provisional target, two kinds of odorous substances, 1-Nonanol and (−)-Carvone, were selected. 1-Nonanol smells like citronella oil and (−)-Carvone smells like spearmint. An odor generated by mixing these two substances smells a similar odor of ($$+$$+)-Carvone which smells like sweet caraway. In order to separate each substance from the mixture, adsorbents were selected based on the molecular diameters and adsorption capability. Sensory tests with the triangle test were conducted to assess the separation capability of the selected adsorbents. An expected performance was not observed. More detail investigation including quantitative measurement with a gas chromatography will be needed for future work.