Base building features that affect indoor air quality should be considered in the site selection process. Features such as quality of light, operability of windows, acoustic separation, and effectiveness of mechanical ventilation and filtration systems contribute to the quality of the indoor environment. Building policies affecting air quality, such as “green” janitorial practices and integrated pest management can be negotiated during the LOI and lease periods; however, the negotiation process will obviously be simpler if the desired policies are already in place.