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Puget Sound Basin Air Pollutant Visualization

Columbia Cascades Support Office
Craig Dalby
Air quality is a major concern at many national parks, including those in the Puget Sound Basin where Mount Rainier National Park is especially hard impacted. Increased air pollution, such as nitrous oxides or NOx, has led to degradation of park resources, including vegetation and aquatic biota, as well as scenic vistas. Ultimately, the solution to the problem is reducing emissions of NOx and other pollutants.

Previous efforts to reduce emissions in the Puget Sound Basin have focused on point sources, including a coal-burning power plant. The largest remaining sources of pollutants, however, are from non-point sources, primarily automobiles. In an effort to help educate the public on the detrimental effects of automobile emissions on national park resources the National Park Service undertook a project to develop a three-dimensional, dynamic display of air pollutant flows in the Puget Sound Basin.

With funding from the Pacific West Regional GIS Call the National Park Service contracted with the University of Washington’s Center for Environmental Visualization to create an animated depiction of NOx spreading through the Puget Sound Basin on a typical summer day in 2002. When this summer weather pattern occurs the prevailing northerly winds blow pollutants south of the urban zone toward Mount Rainier. In addition to the direct impact from nitrogen deposition in the park, the build-up of NOx in the atmosphere also leads to the creation of ozone, resulting in further park resource degradation.

The animation shows four NOx isosurfaces – three-dimensional shapes that define a constant measured value – representing, respectively, 20, 40, 60, and 80 parts per billion. The higher the value, the more opaque the isosurface is displayed. Data for the visualization was provided by the Washington State University Air Indicator Report for Public Access and Community Tracking (AIRPACT) project.

The slides included here from the animation show how a plume of NOx built up during the morning rush hour on September 5, 2002, spread southward and swept over Mount Rainier National Park around mid-afternoon, then slowly dissipated after the evening rush hour. It should be kept in mind that the NOx concentrations shown in this animation are not measured for this specific date, but are rather modeled on average expected values. The air flows, however, are based on actual weather data for the date of the animation.

The completed animation will be posted on the National Park Service Internet site, and may become part of a kiosk display at the park. Future developments may include modeling NOx and ozone for multiple dates, and possibly a real-time Internet-based animation.

(Note to Map Book reviewers: No ESRI software was used in this project.)
April 08, 2004