Retail stores have many sources of indoor air contaminants that can cause potential health and odor concerns. One way to control exposure to these contaminants is to provide adequate ventilation. This study aims to characterize the whole-building emission rates of contaminants in certain retail types. The pilot study included two grocery stores and three furniture stores in northern California. We measured simultaneously the building ventilation rates by SF6 decay and contaminant concentrations in each store for one to two days. Contaminants were measured at multiple indoor locations and at one outdoor location near the building. Formaldehyde, acetaldehyde, and acrolein are three compounds with concentrations above health guidelines in some stores. In several cases, indoor concentrations of certain VOCs and PM were higher indoors than outdoors, suggesting potential indoor sources. Our goal is to characterize the range of contaminant source strengths in 25 to 30 stores in California.