The EMAP program has been organized into three primary elements: Multi-Tier Design, Indicators, and Index Sites. The Index Sites program (DISPro - Demonstration Intensive Site Project) is the primary activity within the Index Sites element of EMAP. This project represents an inter-agency effort between EPA/ORD and DOI/NPS to develop a demonstration of an intensive site network of monitoring and research locations throughout the United States, utilizing the Nation's parklands as "outdoor laboratories." Twelve parks were selected to establish this demonstration. These 12 parks were selected because they are readily accessible, have a history of monitoring environmental information, and represent a broad spectrum of ecological communities. EMAP, through DISPro, is examining whether a "network" of sites existing within the parks can be used to address monitoring issues for global-scale environmental stressors (e.g., air pollution) as well as locale-specific stressors (e.g., air deposition, water-borne) and coordinated with cause-effect, issue-based research related to these environmental stressors. As a first activity, EPA will provide each of the sites with the instrumentation to monitor UV-B. The intent of the program is to initiate a consistent air monitoring program at each site to be followed by consistent monitoring within other media. The project will initiate research projects at all the sites (eventually) to examine the effects of environmental stressors of importance at each of the sites.