See a slideshow of plants and animals — from river otters to salamanders — that air pollution is affecting in the Eastern United States. Get Involved Join the Conservancy’s online community and you can explore new places, receive emails you want and build your own personalized nature page! "The more we look, the more evidence we find, and the worse it seems to get." — Tim Tear, Nature Conservancy scientist and co-author of the report Acidity of Precipitation Across the United States, 2004-06 (Click to enlarge the map) This map shows the acidity of precipitation across the lower 48 states of the United States as measured by the National Atmospheric Deposition Program. Red indicates regions where the precipitation is more acidic (lower pH), and green and blue indicates areas that are less acidic (higher pH). The dots represent locations of the monitoring stations. Acid rain is just one of the air pollutants examined in the report. (Map courtesy of EPA Clean Air Status and Trends Network.) Go Deeper Read the Full Report Download the PDF of "Threats from Above: Air Pollution Impacts on Ecosystems and Biological Diversity in the Eastern United States." Q&A with the Co-Authors Learn more about air pollution's effects on humans and nature in this Q&A with report co-authors Tim Tear and Gary Lovett. Press Release on the Report Get more details on the report in this press release from the Conservancy and the Cary Institute of Ecosystem Studies. Science at The Nature Conservancy Read reports, articles and Q&As from some of the Conservancy's more than 700 staff scientists — and find out why the Conservancy is truly science-based. The Next Big Ideas in Conservation What's the future of protecting nature? Explore it with cutting-edge ideas from eight Conservancy scientists. Sensitivity to Acid Deposition, Eastern United States (Click to enlarge the map) This map shows landscape sensitivity to acidic deposition for the Northeastern and Mid-Atlantic divisions of the Nature Conservancy. (Map from Cosby, Bernard J. and Charles T. Driscoll. 2007. "Assessing the Threat of Atmospheric Deposition: Scope and Severity for Ecoregional Portfolio Targets in the Eastern U.S. Conservation Region of the Nature Conservancy." A report from the University of Virginia to The Nature Conservancy. In review.) "Air pollution doesn't recognize regional boundaries — we need a national solution." — Gary Lovett, senior scientist at the Cary Institute for Ecosystem Studies and co-author of the report. Get Involved Join the Conservancy’s online community and you can explore new places, receive emails you want and build your own personalized nature page!

By Robert Lalasz

Air pollution is substantially harming every major ecosystem type in the northeastern and mid-Atlantic United States — according to a new report co-written by experts from The Nature Conservancy and the Cary Institute of Ecosystem Studies.

And the report's co-authors say pollutants ranging from mercury to ground-level ozone are degrading the services nature provides us, too — resulting in smaller fish stocks, reduced agricultural production, and even a decline in honey bee populations.

"We have yet to fully understand all the impacts, but they're large," says Tim Tear, a Nature Conservancy scientist and co-author of the report. "The more we look, the more evidence we find, and the worse it seems to get."

But pollution deposition is neither adequately measured nor regulated, according to the report — which calls for new pollution limits and science-based policies to remedy this growing crisis.

Significant Environmental Problems in Air, Soil and Water

This report — based on a conference of 32 experts organized by the Conservancy and the Cary Institute — is the first effort to pull together all the research on how air pollution is affecting nature in the northeastern and mid-Atlantic states.

It finds that nitrogen, acid deposition, mercury and ground-level ozone not only contaminate the air we breathe — they're entering our soils and waters, causing significant environmental issues:

• High levels of deposited mercury are having negative impacts on wildlife — from salamander species in the Appalachian Mountains to loons in the Adirondacks and bald eagles in Maine.
• Ground-level ozone reduces plants' ability to harness sunlight for growth, reducing forest and crop production throughout the eastern United States.
• Excess nitrogen — in part from air pollution — is harming waterways, fish and shellfish from Rhode Island's Narrangansett Bay to Long Island Sound to Chesapeake Bay.
• Nitrogen also decreases the disease resistance of trees, leaving them more vulnerable to pests and pathogens.
• Acid rain is making sensitive lakes and streams uninhabitable by fish in the mountains of the Northeast and the Southern Appalachians. On land, it leaches important nutrients from foliage and soil, reducing the productivity of some forest trees.

And the impact on the services nature provides humans is also significant — from decreased timber production in acidified forests to mercury levels so high they have prompted restrictions on freshwater fishing.

"Air pollution is most often pitched as directly impacting humans through respiratory problems," says Tear.

"We want this report to raise awareness of the direct and indirect impacts on nature — and because we depend on nature, those impacts also affect humans."

Read this Q&A with Tear and report co-author Gary Lovett of the Cary Institute for more on the impact of air pollution on the services nature provides humans.

'Critical Loads' for Air Pollution and Ecosystems

The report calls for key changes in the way the United States regulates air pollution and evaluates its effects:

• Better regulations: The United States needs to establish what the critical air pollution loads are for ecosystem health — the precise levels that cause negative effects on ecosystems — and use these loads to refocus and expand air pollution regulation to address ecosystem effects.

Europe has used critical loads for regulating air pollution for over a decade, and some U.S. agencies have already established critical loads for particular landscapes. But these initiatives need to be scaled up dramatically, according to the Cary Institute's Lovett.

“We need a new way of thinking about how to regulate air pollution to protect ecosystems,” says Lovett. “Critical loads provide a way of measuring pollution that is more relevant to wildlife and natural habitats.”

• Better monitoring: Current programs for monitoring air pollution and its effects are fragmented, underfunded and have serious gaps, according to the report. The authors maintain that the nation should develop a more integrated monitoring approach that includes air, water, forests, soils and wildlife.

"We can't get a sense of the impacts on ecosystems and biological diversity without this information," says Lovett.

Air Pollution Doesn't Respect Boundaries

“Everyone has a role to play,” Tear says. “Congress should direct the Environmental Protection Agency to develop and implement critical loads, while the EPA should use the best available science to establish these loading levels."

"Federal land management agencies and conservation organizations need to work together with research scientists," Tear adds. "They should offer their lands and waters to advance critical loads research.”

And people in other parts of the country shouldn't take comfort from the report's focus on an eastern U.S. region, says Lovett.

"Other regions of the United States such as the Rocky Mountains and California are also quite concerned about these effects in their backyards," says Lovett. "Air pollution doesn't recognize regional boundaries — we need a national solution."

Robert Lalasz is senior editorial manager for nature.org

(July 2008)

Nature picture credits (left to right): © Eric Middelkoop/BigStockPhoto (smokestack); Alain Turgeon/BigStockPhotos.com (river otter)