The report, "Threats From Above: Air Pollution Impacts on Ecosystems and Biological Diversity in the Eastern United States," by the Cary Institute of Ecosystem Studies and the Nature Conservancy is the first to analyze effects four air pollutants have across a variety of habitat types, the institutions said in a news release.

The assessed pollutants -- sulfur, nitrogen, mercury and ground-level ozone -- typically originate from smokestack industries, tailpipes and agricultural operations, researchers said. Although airborne initially, the pollutants return to land, where they contaminate the soil and water.

"Everywhere we looked, we found evidence of air pollution harming natural resources," said Gary Lovett, an ecologist at the Cary Institute and the report's lead author. "Decisive action is needed if we plan on preserving functioning ecosystems for future generations."

How people think about air pollution must go beyond measuring air quality to capturing "actual impacts to natural areas, wildlife, and the services they provide," Lovett said.

The authors urge U.S. policymakers to establish air quality standards based on critical loads or the maximum amount of deposited pollution an ecosystem can tolerate before it is harmed.