PROJECT SUMMARY/ABSTRACT We can measure the brightness of a color and the loudness of a sound because we have related these perceptual properties to physical properties. This has not been done for olfaction. Knowing the basic unit of intensity is essential to understand other aspects of a sense. For instance, just as color shifts with brightness, the smell of an odor is relative to its intensity. In fact, most naturally occurring odors are not one molecule, but mixtures of many molecules at different intensities. At the olfactory receptor level, we know that one odorant may inhibit another leading to a change in each other’s strength. Knowing how and what interactions take place in an odor mixture has clinical relevance. If we understand interactions in odor mixtures, we could suppress unappetizing odorants in medicines that lead to lack of compliance as well as increase palatable odorants in individuals with partial loss (e.g. elderly). Furthermore, knowing mixture intensity will supplement fields trying to accurately measure odors (environmental regulation) or recreate them (food science). In this proposal, I will collect high-quality, public data sets linking molecular structure to perceived intensity and build open-access tools to provide practical, accessible predictions to advance the scientific field.