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Monitoring air quality in Southeast Alaska’s National Parks and Forests: Linking atmospheric pollutants with ecological effects

Formally Refereed

Abstract

Air quality and air quality related values are important resources to the National Park Service (NPS) units and Wilderness areas in northern Southeast Alaska. Air quality monitoring was prioritized as a high-priority Vital Sign at the Southeast Alaska Network’s (SEAN) Inventory and Monitoring Program’s terrestrial scoping workshop (Derr and Fastie 2006). Air quality monitoring of fossil fuel combustion emission products and heavy metals was conducted at several sites in the Southeast Alaska Network (SEAN) parks, the Tongass National Forest’s Tracy Arm-Fords Terror Wilderness, and in the Skagway Borough from the May through September tourist seasons in 2008 and 2009. Passive samplers were deployed to measure average weekly ambient atmospheric concentrations of nitrogenous and sulfurous gaseous pollutants, and ion exchange resin tube samplers were deployed to measure seasonal bulk and throughfall deposition of nitrogen and sulfur compounds. Elemental concentrations of nitrogen, sulfur, and toxic metals in lichen samples were assessed at sites in all SEAN parks and reassessed at sites that were sampled in 1999 in and near Klondike Gold Rush NHP (KLGO). Epiphytic lichen communities were compared to reference sites in the Tongass National Forest. Lichen assemblages near the Skagway cruise ship terminal displayed shifts towards species favoring enhanced nitrogen and sulfur deposition while other sites in the study area hosted lichen communities indicative of clean sites. Atmospheric concentrations of air pollutants, deposition, and concentration of some elements, including sulfur, lead, zinc, and vanadium, in lichen samples near Skagway’s ship docks were considerably elevated above background levels. Occasionally, weekly average ambient concentrations of nitrogen and sulfur containing compounds were elevated in Dyea and Sitka, probably due to atmospheric conditions during those weeks. Unusual very high spikes in ammonia were detected at several sites, and an especially high, difficult to explain, spike was detected at the Dewey 1700 site. Presence of lichen species indicative of excessive nutrient nitrogen deposition occurred at Sawyer Island in Tracy Arm-Fords Terror Wilderness, Dyea, and the Upper Dewey Lake Trail at 1480 ft. In general, as the distance increased from human activity centers, levels of pollutants declined. Most sites exhibited pristine or global background condition as expected for rural Southeast Alaska. Although greater trans-Pacific emissions associated with industrial expansion and energy production in Asia and more wildfires emissions from northern Alaska/Canada contribute to background regional nitrogen oxide levels, nitrogen levels in epiphytic lichens did not increase significantly since 1999 except near local, seasonal sources of pollution. This study demonstrated that local emission sources have a greater impact on air quality impacts than distant sources.

Keywords

Air Quality, Alaska, Atmospheric deposition, Passive samplers, Lichen, Skagway, Cruise ship

Citation

Schirokauer D.; Geiser, L.; Bytnerowicz, A.; Fenn, M.; Dillman, K. 2014. Monitoring air quality in Southeast Alaska’s National Parks and Forests: Linking atmospheric pollutants with ecological effects. Natural Resource Technical Report. NPS/SEAN/NRTR—2014/839. National Park Service. Fort Collins, Colorado.
https://www.fs.usda.gov/research/treesearch/49399