This project synthesizes available inventories and published findings regarding air quality related values (AQRVs) sensitive to effects caused by atmospheric deposition of nitrogen, sulfur, and toxic compounds; formation of ground-level ozone; and impacts of air pollution on in-park visibility. Such effects include those associated with acidification, nutrient enrichment, visibility impairment, and toxicity to fish and wildlife. Available information and data were compiled on the most sensitive AQRVs in the 32 park networks within the National Park system throughout the United States. Data were gathered for individual parks where available. Park-specific analyses focus primarily on those parks thought to contain the greatest concentration of air pollution-sensitive resources. There is a growing body of scientific research demonstrating that atmospheric deposition and other aspects of air pollution induce a range of effects on aquatic and terrestrial ecosystems and visual resources from subtle to severe. We evaluated the status of these air pollution-sensitive resources, along with available model simulations of critical pollutant deposition load and future prognosis for damage or recovery. This project begins the process of synthesizing and assessing the available information on AQRVs in the national parks throughout the United States. Information provided here will be needed to develop AQRV inventories and to guide future management, research, and monitoring actions.