The Nitrogen Footprint Tool for Institutions: Comparing Results for a Diverse Group of Institutions

Abstract:

Anthropogenic production of reactive nitrogen (Nr) has drastically altered the nitrogen cycle over the past few decades by causing it to accumulate in the environment. A nitrogen footprint (NF) estimates the amount of Nr released to the environment as a result of an entity’s activities. The Nitrogen Footprint Tool (NFT) for universities and institutions provides a standardized method for quantifying the NF for the activities and operations of these entities. The NFT translates data on energy use, food purchasing, sewage treatment, and fertilizer use to the amount of Nr lost to the environment using NO_x and N₂O emission factors, virtual nitrogen factors (VNFs) for food production, N reduction rates from wastewater treatment, and nitrogen uptake factors for fertilizer.

As part of the Nitrogen Footprint Project supported by the EPA, seven institutions (colleges, universities, and research institutions) have completed NFT assessments: University of Virginia, University of New Hampshire, Brown University, Dickinson College, Colorado State University, Eastern Mennonite University, and the Marine Biological Laboratory. The results of these assessments reveal the magnitude of impacts on the global nitrogen cycle by different activities and sectors, and will allow these institutions to set NF reduction goals along with management decisions based on scenarios and projections in the NFT. The trends revealed in early analysis of the results include geographic differences based on regional energy sources and local sewage treatment, as well as operational differences that stem from institution type and management. As an example of the impact of management, the amount and type of food served directly impacts the food production NF, which is a large percentage of the total NF for all institutions (35-75%). Comparison of these first NF results will shed light on the primary activities of institutions that add Nr to the environment and examine the differences between them.