You are here:
Chain Reaction: A Detailed look at Reactive Nitrogen and Possible Management Approaches
Citation:
Hogrefe, C. Chain Reaction: A Detailed look at Reactive Nitrogen and Possible Management Approaches. EM Magazine. Air and Waste Management Association, Pittsburgh, PA, , 4-5, (2016).
Impact/Purpose:
The National Exposure Research Laboratory’s Atmospheric Modeling Division (AMAD) conducts research in support of EPA’s mission to protect human health and the environment. AMAD’s research program is engaged in developing and evaluating predictive atmospheric models on all spatial and temporal scales for forecasting the Nation’s air quality and for assessing changes in air quality and air pollutant exposures, as affected by changes in ecosystem management and regulatory decisions. AMAD is responsible for providing a sound scientific and technical basis for regulatory policies based on air quality models to improve ambient air quality. The models developed by AMAD are being used by EPA, NOAA, and the air pollution community in understanding and forecasting not only the magnitude of the air pollution problem, but also in developing emission control policies and regulations for air quality improvements.
Description:
Nitrogen is one of the building blocks of life, yet excessive amounts in the environment can cause problems in various ecosystems. Abundant in the atmosphere as dinitrogen (N<SUB>2</SUB>), nitrogen needs to be combined with other elements such as hydrogen or oxygen to form compounds collectively known as reactive nitrogen before it can be used by most living organisms. This process is referred to as fixation. Natural pathways for creating reactive nitrogen are biological fixation by algae and bacteria hosted by leguminous crops such as soybeans and alfalfa as well as the production of nitrogen oxides from lightning. Man-made pathways include the production of synthetic fertilizer through the Haber-Bosch process and the combustion of fossil fuels. The advent of synthetic fertilizer production in the early 20th century has increased food security around the globe and has helped to support a growing global population. However, increasing use of synthetic fertilizer as well an increase in livestock have also had adverse effects on aquatic ecosystems through run-off and leaching that can lead to eutrophication of waterbodies. The burning of fossil fuels has led to changes in atmospheric chemistry and composition which in turn can affect concentrations of harmful pollutants such as ozone, alter the radiative balance of the atmosphere, contribute to changes in stratospheric ozone levels, and lead to acidification of terrestrial and aquatic ecosystems through deposition.
