Air quality related values (AQRVs) for Central Alaska Network (CAKN) parks: Effects from ozone; visibility reducing particles; and atmospheric deposition of acids, nutrients and toxics

Sullivan, Tomothy

This report describes the Air Quality Related Values (AQRVs) of the Central Alaska Network (CAKN). AQRVs are those resources sensitive to air quality and include streams, lakes, soils, vegetation, fish and wildlife, and visibility. The CAKN parks that are included in the NPS Inventory and Monitoring (I&M) Program, and discussed in this report, are Denali National Park (DENA), Wrangell-St. Elias National Park and Preserve (WRST), and Yukon-Charley Rivers National Preserve (YUCH). DENA is designated as Class I, giving it a heightened level of protection against harm caused by poor air quality under the Clean Air Act (CAA). Sullivan et al. (2011a, 2011b) and Kohut (2007a) conducted risk assessments for acidification, eutrophication, and ozone (O3) for the CAKN parks; their results are described in this report. This report also describes air pollutant emissions and air quality in CAKN, and their effects on AQRVs. The primary pollutants likely to affect AQRVs include nitrogen (N) and sulfur (S) compounds (nitrate [NO3-], ammonium [NH4+], and sulfate [SO42-]); ground-level O3; haze-causing particles; and airborne toxics. Background for this section can be found in “Air Quality Related Values (AQRVs) in National Parks. Effects from Ozone; Visibility Reducing Particles; and Atmospheric Deposition of Acids, Nutrients and Toxics” (Sullivan 2016). The parks in the CAKN are relatively isolated from human activities and air pollutant emissions, in comparison to parks in the contiguous 48 states. However, DENA is located 6.1 km from the Healy Power Plant, perhaps the closest proximity of a coal-fired power plant to a Class I national park. Total S and N deposition near this network are both expected to be low due to the scarcity of point sources and urban areas and the low calculated emissions levels from the various boroughs that comprise the network region. The sparse available atmospheric deposition data are consistent with the general understanding that atmospheric deposition of both N and S tends to be very low at national park lands within Alaska and more specifically within the CAKN. In agreement with measured values at DENA, it can be assumed that S and N deposition across this network would each be lower than about 1 kilogram per hectare per year (kg/ha/yr), on average. Sulfur and N pollutants can cause acidification of streams, lakes, and soils. Despite the presumed acid sensitivity of some resources in parks in the CAKN, aquatic and terrestrial acidification have not been documented in this network and are considered unlikely in view of the very low levels of S and N deposition. Acid-sensitive resources constitute potentially important AQRVs, but are at little risk of damage under any reasonable future deposition scenario. File size: 1.6 MB

Air quality related values (AQRVs) for Central Alaska Network (CAKN) parks: Effects from ozone; visibility reducing particles; and atmospheric deposition of acids, nutrients and toxics

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