NPS: Explore Nature» Air Resources Division

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National Park Service

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U.S. Department of the Interior

Explore Air

NPS » Explore Nature » Air » Basics » Effects » Ozone » Tree Growth » Aspen

US map showing NPS critical load study locations.

U.S. Department of the Interior

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updated on 04/06/2009 I http://www.nature.nps.gov/air/aqbasics/TreeGrowth/aspen.cfm I Email: Webmaster