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Airborne pollutants harm diverse habitats

Photo by Bubblejewel

If you are living in the eastern United States, the environment around you is being harmed by air pollution. From Adirondack forests and Shenandoah streams to Appalachian wetlands and the Chesapeake Bay, a new report by the Cary Institute and The Nature Conservancy has found air pollution is degrading every major ecosystem type in the northeastern and mid-Atlantic United States.

The report, "Threats From Above: Air Pollution Impacts on Ecosystems and Biological Diversity in the Eastern United States," is the first to analyze the large-scale effects four air pollutants are having across a broad range of habitat types. The majority of recent studies focus on an individual pollutant. More than 32 experts contributed to the effort; the prognosis is not good.

"Everywhere we looked, we found evidence of air pollution harming natural resources," said Gary M. Lovett, Ph.D., 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."

Co-author Timothy H. Tear, Ph.D., of The Nature Conservancy, notes, "Deposited pollutants have tangible human impacts. Mercury contamination results in fish that are unsafe to eat. Acidification kills fish and strips nutrients from soils. Excess nitrogen pollutes estuaries, to the detriment of coastal fisheries. And ground-level ozone reduces plant growth, a threat to forestry and agriculture."

The report urges U.S. policymakers to establish air quality standards based on critical loads. This is defined as the maximum level of deposited pollution ecosystems can tolerate before harmful effects occur. By establishing thresholds, pollutants can be regulated in a way that preserves functioning ecosystems. In some areas, such as Rocky Mountain National Park, federal agencies have already adopted this approach to evaluate air pollution threats. It is also being used to regulate air pollution throughout Europe.

Establishing critical loads will require renewed investment in monitoring programs for air pollution and the ecosystems it affects. "We can't assess if ecosystems are harmed by air pollution if we don't monitor them. While some good pollution monitoring programs exist, our current system is fragmented, underfunded and has serious gaps," Lovett said.

While there may be initial costs to ramping up monitoring efforts, consider the alternative. The fishless lakes of th Adirondacks are a harsh reminder air pollution does not recognize property lines. Tear concludes, "In the absence of critical loads, there is a false security in conventional land conservation. We can manage natural areas with the best possible protocols, but we can't really 'protect' the land if it is continually exposed to air pollution."

Did you know?

  • Ground level ozone has been estimated to cause $3-6 billion in reduced crop production annually.
  • Current levels of mercury deposition are 4 to 6 times higher than in 1900. Mercury concentrations in fish frequently surpass the EPA levels set to protect human health.
  • In New York's Adirondack Mountains, more than 40 percent of the lakes are chronically acidic or sensitive to episodic acidification.
  • Over the last century, largely as a result of agricultural activities and fuel combustion, the amount of available nitrogen has doubled.

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