A brown haze indicates a combination of dust, nitrogen dioxide, and nitric oxide from car exhaust, power plants and factories. Click on image for full size (174 Kb) Barry Lefer/MILAGRO

While most of the air in our atmosphere is made of nitrogen gas (two atoms of nitrogen bonded together), there are other gases in our atmosphere that contain nitrogen as well. They may make up only a small percentage of the air molecules in our atmosphere, but their numbers are growing and, even in small amounts, they can cause huge changes in our planet.

Nitric oxide (NO) and nitrogen dioxide (NO2)
Nitrogen dioxide and nitric oxide molecules form during combustion in car engines, power plants, and factories. They can contribute to smog when combined with oxygen molecules and the fumes from paint and gasoline (called Volatile Organic Compounds). They can also contribute to acid rain if mixed with water vapor turning into nitric acid. Nitrogen dioxide will break apart in sunlight and the free oxygen atoms latch onto oxygen molecules forming dangerous ground-level ozone.

Nitrous oxide (N2O)
Also known as “laughing gas,” nitrous oxide is a greenhouse gas. The amount of nitrous oxide in the atmosphere has increased since the beginning of the Industrial Revolution.

Nitrous oxide forms during combustion and is also released into the atmosphere from farm animals, sewage, and fertilizers. There are natural ways that nitrous oxide gets into the atmosphere too, including from tiny microbes that chemically alter nitrogen in the soils of tropical forests.

A brown haze indicates a combination of dust, nitrogen dioxide, and nitric oxide from car exhaust, power plants and factories. Click on image for full size (174 Kb) Barry Lefer/MILAGRO

Most of the air in our atmosphere is made of nitrogen gas. But there are other gases in our atmosphere that contain nitrogen as well. They make up only a small fraction of the air molecules in our atmosphere, but their numbers are growing and, even in small amounts, they are causing huge changes in our planet.

Nitric oxide (NO) and nitrogen dioxide (NO2)
Nitrogen dioxide and nitric oxide molecules form during combustion in car engines, power plants, and factories. They can contribute to smog when combined with oxygen molecules and the fumes from paint and gasoline (called Volatile Organic Compounds). They can also contribute to acid rain if mixed with water vapor turning into nitric acid. Nitrogen dioxide will break apart in sunlight and the free oxygen atoms latch onto oxygen molecules forming dangerous ground-level ozone.

Nitrous oxide (N2O)
Nitrous oxide is a greenhouse gas. It is also known as “laughing gas” because it is known to make people laugh when it is given to medical patients to numb pain. The amount of nitrous oxide in the atmosphere has increased since the beginning of the Industrial Revolution, as Earth’s climate has gotten warmer.

Nitrous oxide forms during combustion, just like nitrogen dioxide, and is also released into the atmosphere from farm animals, sewage, and fertilizers. There are natural ways that nitrous oxide gets into the atmosphere too, including from tiny microbes that alter nitrogen in the soils of tropical forests.

A brown haze indicates a combination of dust, nitrogen dioxide, and nitric oxide from car exhaust, power plants and factories. Click on image for full size (174 Kb) Barry Lefer/MILAGRO

While most of the air in our atmosphere is made of nitrogen gas, there are other gases in our atmosphere that contain nitrogen too. They may make up only a small percentage of the air molecules in our atmosphere, but their numbers are growing and, even in small amounts, they can cause huge changes in our planet.

Molecules with one nitrogen atom and one or two oxygen atoms are called nitrogen oxides. They are made in the engines of cars, in power plants, and in factories. These little molecules can cause smog if they combine with oxygen and the fumes from paint and gasoline. They can also cause acid rain if they mix with water vapor in the air. Sometimes they break apart in sunlight and the oxygen atoms latch onto oxygen molecules forming dangerous ground-level ozone.

Molecules with two nitrogen atoms and one oxygen atom are a greenhouse gas called nitrous oxide. The amount of nitrous oxide in the atmosphere has increased in the past 150 years. More greenhouse gases in the air cause global warming. Nitrous oxide forms in car engines, power plants and factories. It also comes from farm animals, sewage, and fertilizer. There are natural ways that nitrous oxide gets into the atmosphere too, including from tiny microbes in the soils of tropical forests.