Nitrogen—Gases in the Atmosphere

Nitrogen is a part of all plant and animal proteins

Nitrogen is the primary gas in the atmosphere. It makes up 78.084 percent by volume in dry air, and that makes it the most common gas in the atmosphere. Its atomic symbol is N and its atomic number is 7. 

The Discovery of Nitrogen 

Daniel Rutherford discovered nitrogen in 1772. He was a Scottish chemist and a physician with a passion for understanding gases, and he owed his discovery to a mouse.

When Rutherford placed the mouse in a sealed, enclosed space, the mouse naturally died when its air ran low. He then attempted to burn a candle in the space. The flame didn't fare well either. He tried phosphorous next with much the same result. 

He then forced the remaining air through a solution that absorbed the carbon dioxide that remained in it. Now he had "air" that was devoid of both oxygen and carbon dioxide. What remained was nitrogen, which Rutherford initially called noxious or phlogisticated air. He determined that this remaining gas was expelled by the mouse before it died. 

Nitrogen in Nature 

Nitrogen is a part of all plant and animal proteins. The nitrogen cycle is a pathway in nature that transforms nitrogen into usable forms. Although much of the fixation of nitrogen occurs biologically, such as with Rutherford's mouse, nitrogen can be fixed by lightning as well. It's colorless, odorless and tasteless. 

Everyday Uses for Nitrogen

You may regularly consume traces of nitrogen because it's often used to preserve foods, particularly those that are prepacked for sale or sold in bulk. It delays oxidative damage—rotting and spoiling—by itself or when combined with carbon dioxide. It's also used to maintain pressure in beer kegs. 

Nitrogen powers paintball guns. It has a place in making dyes and explosives. 

In the health care field, it's widely used in pharmacology and is commonly found in antibiotics. It's used in X-ray machines and as an anesthetic in the form of nitrous oxide. Nitrogen is used to preserve blood, sperm and egg samples. 

Nitrogen As a Greenhouse Gas

Compounds of nitrogen, and particularly nitrogen oxides NOx, are considered greenhouse gases. Nitrogen is used as a fertilizer in soils, as an ingredient in industrial processes, and is released during the burning of fossil fuels. 

Nitrogen's Role in Pollution  

Sharp rises in the amount of nitrogen compounds measured in the air began surfacing during the Industrial Revolution. Nitrogen compounds are a primary component in the formation of ground-level ozone. In addition to causing respiratory problems, nitrogen compounds in the atmosphere contribute to the formation of acid rain.

Nutrient pollution, a major environmental problem in the 21st century, results from excess nitrogen and phosphorous accumulated in water and air. Together, they promote underwater plant growth and algae growth, and they can destroy water habitats and upset ecosystems when they're allowed to proliferate unchecked. When these nitrates find their way into drinking water—and this sometimes occurs—it presents health dangers, particularly for infants and the elderly.