This work reports about polymer-nanostructured carbon composite (PNCC) and it possible application for relative humidity registration and volatile organic compound (VOC) detection in the air. PNCC have been produced using high structured carbon black (HSCB) nanoparticles and polyisoprene (PI), ethylenevinylacetate (EVA) copolymer, polyvinylacetate (PVAc), polyethylene glycol (PEG) and polyvinylalcohol (PVA). Matrix material for composite production has been selected with respect to desired analyte to bee tested. Composites show selective response to particular species of analytes vapour. It has been found that humidity sensing mechanism changes from proton conductivity to electron tunnelling by addition of HSCB to PVA matrix. Plasticizer effect on PVAc-NCC ethanol vapour sensitivity has been evaluated.