This report is concerned with the perception of odor intensity by human beings. It focuses in particular on (a) how perceived magnitude changes during prolonged exposure to an odorant; (b) how perceived magnitude varies with concentration for various odorants; and (c) how the presence of low concentrations of a masking agent alters the perceived magnitude of a test odorant.

The report comprises two parts. Part I deals with perception of intensity and adaptation for I-propanol and eugenol. Part II deals primarily with perception of intensity, adaptation, and masking for ozone and n-butyl acetate.