In this paper, we describe and demonstrate an approach to illustrate the performance of buildings with respect to indoor air quality (IAQ). In the absence of an adequate or agreed-upon IAQ metric(s), we describe a graphical approach to presenting IAQ performance. This approach displays measured or predicted levels of indoor contaminants relative to health-based guidelines or other reference values. We then demonstrate our approach using (a) measured data from a study of small commercial buildings and (b) simulated data of interventions in a kitchen with an improperly tuned stove. The development and application of this graphical approach leads to several challenging questions regarding how to characterize building IAQ performance, including the determination of which contaminants to measure where and when, relevant contaminant reference values, and the interactions among multiple contaminants. This paper discusses these questions with the intent of promoting future dialogue on how to characterize IAQ performance with measured (or modeled) data. Lastly, we briefly describe extending this graphical approach to illustrate the performance of buildings with respect to other building parameters (e.g., energy and water consumption) in addition to IAQ.