Purdue Climate Change Research Center

Doering chairs EPA’s Science Advisory Board Integrated Nitrogen Committee

In August, 2011, the Environmental Protection Agency’s (EPA) Science Advisory Board’s Integrated Nitrogen Committee released their findings in a new report entitled, Reactive Nitrogen in the United States: An Analysis of Inputs, Flows, Consequences and Management Options. Professor Otto Doering chaired the team of science advisors leading the five-year study which is the first to quantify the sources and risks of nitrogen pollution (reactive nitrogen) in the United States. The report finds that in the U.S., “human activities across multiple sources currently introduce more than five times the reactive nitrogen into the environment than natural processes.” When released into the environment in large quantities, reactive nitrogen can severely damage ecosystems, impact our climate system, and adversely affect health.

While it is well know that the primary sources of nitrogen pollution are agriculture and the burning of fossil fuels, the report highlights that, unlike other pollutants, once reactive nitrogen makes it into the environment, it causes a “cascading sequence of events, resulting ultimately in harm to the natural balance of our ecosystems,” said University of Virginia environmental sciences professor James Galloway, a co-author of the report.

For example, NOX emissions from a tailpipe will contribute to the formation of ozone, then smog, and then acidify soil when it settles out of the atmosphere. From the soil, it can be washed into rivers and streams, causing algal blooms and ultimately evaporating back as the greenhouse gas nitrous oxide which warms the troposphere, and also destroys stratospheric ozone.

Findings from the report show that a 25% reduction in excess reactive nitrogen is achievable in the coming decade with available technology, if there is the will to do so. The report urges government agencies to take action and set goals for controlling excess reactive nitrogen. Doering has recently served on several committees for the National Academies that have made similar recommendations after investigating the nutrient problems in the Mississippi River Basin.

The Integrated Nitrogen Committee’s report is having a profound impact on the way EPA and other agencies are approaching the nitrogen problem. the board recommends more integrated approaches to researching and regulating nitrogen in part to prevent nitrogen-cutting "solutions" in one program from causing inadvertent problems in another. they also recommend improved communication between its researchers who study air and water, and better communication with colleagues at the U.S. departments of agriculture and energy, who also work on nitrogen pollution.

The Integrated Nitrogen Committee’s leadership team, including Jim Galloway from the University of Virginia and Tom theis from the University of Illinois, Chicago, has participated in numerous briefings and meetings to highlight this issue and suggest alternative approaches that might be utilized successfully to reduce excess reactive nitrogen.

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