Reactive Nitrogen Fact Sheet

Nitrogen pollution threatens coastal waters

Nitrogen is literally all around us, including nearly 80 percent of each breath we take. Though it is the most plentiful element in the earth’s atmosphere, it’s unusable in its inert state and must be transformed into reactive nitrogen before plants and animals can use it to make protein, DNA, and other compounds essential for life. Yet changes to the nitrogen cycle, like the more well-known changes to the carbon cycle, are creating environmental havoc.

100 years ago, chemists invented a process to turn the inexhaustible resource of inert nitrogen gas in the atmosphere into reactive, biologically available nitrogen in the form of ammonia. A few decades later, the widespread use of synthetic nitrogen to fertilize croplands had boosted global food production and helped to catapult world population from 1.6 billion to six billion during the 20th century.

Higher crop yields – a mixed blessing

In the last 50 years, a dramatic increase in the use of chemical fertilizer and fossil fuels has been matched by an equally dramatic rise in nitrogen pollution. Reactive nitrogen helps grow food and biofuel crops. And almost all of it eventually escapes to the environment. While some ends up in the food we eat, most ends up in the atmosphere or ingroundwater, freshwater, or ocean ecosystems, where it can cause a host of environmental and health problems. That’s because a single molecule of reactive nitrogen can pack a wallop as it moves through the environment. It can worsen climate change, air and water pollution, coastal dead zones, and cause biodiversity loss.

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