This project synthesized 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 and from regional and national databases. Park-specific analyses focused primarily on those parks thought to contain the greatest concentration of air pollution-sensitive resources. 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 information provided a foundation for developing AQRV inventories and guiding future management, research, and monitoring actions. Project was completed in 2016.