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Web maps

AirAtlas is a series of web maps that provide visualization of estimated air quality statistics for atmospheric deposition, ozone, and visibility in the contiguous U.S. The AirAtlas webmaps also show National Park Service (NPS) units and relevant monitoring locations for each of the air pollutant categories. Web map interpolations show five-year average statistics in order to smooth out the variability that can occur in a single year. Specific estimates of each statistic are available for every NPS unit in the contiguous U.S.

About the Estimates

Annual statistics are calculated from data collected at each monitor location and averaged over five years to derive the five-year average statistic. Five-year average statistics are then interpolated across the conterminous U.S. using the Inverse Distance Weighting (IDW) technique in a Geographic Information System (GIS). This creates estimated values for the conterminous U.S., including areas where observed monitor data are unavailable (i.e. between the monitors). The interpolated value for each NPS unit is obtained at the center of the unit (for units that are made up of more than one location, the center of the largest location is used). It is important to note that interpolated values are estimates. For parks with onsite monitoring, the interpolated statistic at the park center may differ from the statistic calculated using data from the onsite monitor(s).

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Last Updated: November 18, 2015