This field study was organized to determine the ventilation required to maintain acceptable air quality in a retail store using the ASHRAE Standard 62-1989 performance-based procedure. Pollutant concentrations and ventilation rates were measured in a large retail store during four one-week intervals. The measurement intervals were each separated by three months to allow different weather conditions and mixes of retail stock to be present over the one-year field study in a cold continental climate. Pollutants monitored were formaldehyde, carbon dioxide, carbon monoxide, particle size distributions and concentrations, and selected and total volatile organic compounds. Environmental parameters monitored were indoor and outdoor temperatures, pressure differentials, relative humidities, and ventilation rates (duct flows [L/s] and tracer gas [SF6] measurements). Total volatile organic compounds was the pollutant class that required the highest ventilation rate to control its concentration. Nonetheless, this rate (0.5 L/s-m2) is less than those specified in the prescriptive portionofASHRAE62-1989 for retail spaces (1.5 L/s-m2). Unusually high pollutant concentrations were observed for short periods and corresponded with cleaning and maintenance activities.