Atlas of the Biosphere

Ozone in the Atmosphere

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What is Ozone?
Ozone is gas that natually occurs in our atmosphere. Chemically speaking, it is a molecule containing three Oxygen atoms. Because this particular configuration of atoms is unstable, Ozone is a considered a volitile chemical. In fact, simple interactions with sunlight drive both its creation and destruction.

Where does Ozone come from?
Ozone is generated in two different ways:
- A pre-existing Ozone molecule is absorbs some ultra-violet radiation, causing it to split in to two pieces. One of the pieces is a group of two Oxygen atoms, a chemical configuration otherwise known as molecular oxygen. The other piece is a single Oxygen atom. The free oxygen atom then collides with a molecular oxygen molecule generated by another similar reaction nearby, and the two fuse to form a new Ozone molecule. This process occurs in the upper atmosphere at a very fast rate.
- Nitrogen oxide mixes with volitile organic compounds (VOC's) - both large components of automobile exhaust - and sunlight to produce Ozone molecules. This reaction generally takes place near the surface of the Earth, and more specifically near large cities. The ozone produced in this manner is commonly called smog, and is what causes the sky to appear hazy on otherwise clear days.

How can Ozone be both good and bad?
The three rules of retail are location, location, location... and that goes for ozone as well. As was already mentioned, Ozone that occurs in the upper reaches of the atmosphere interacts with ultra-violet radiation coming from the sun. This interaction keeps most of that UV light from hitting the surface of the Earth, where it would cause serious problems for the plants and animals living there. So upper-level Ozone acts as a protective blanket that shields the Earth from harmful radiation, and therefore is often called good ozone. Surface level Ozone, having no UV blocking purpose, acts only to hamper the lung capacity of those who are unfortunate to breathe it. Young children and the elderly are the most seriously affected by this dangerous chemical, but even otherwise healthy people become weak and have difficulty breathing after only a few hours of exposure.

What's the problem?
Basically, human activities are causing the planet to lose good Ozone all the while gaining bad Ozone. Once they make it to the upper atmosphere, Chlorofluorocarbons (CFC's) - a chemical commonly found in spray can propellants until around 1994 - get into the Ozone chemical reaction, making it easier for Ozone to break apart in the presence of sunlight but making it almost impossible for it to reform again. This process leads to what is commonly called the hole in the Ozone layer. The Ozone hole is expected to reseal itself sometime in the next 50 years or so, however the amount of damage it will cause in the meantime could be massive. As for surface level Ozone, automobile and factory emissions are not expected to diminish in the near future. Thus, the increased levels of VOC's and NOx's in the lower atmosphere will lead to increased Ozone levels and further Ozone related health problems.

Artwork by Maija Swanson and Nick Olejniczak