Since at least the early 1990s, a recurring topic in the media has been the ozone “layer.” There have been many facts, myths and suppositions stated about ozone. Unfortunately, many of the myths and suppositions have taken more of a center stage than have the facts. Many people might be surprised at some of the facts about the ozone layer.
Ozone hole
Many people have been taken in by reports of an ozone hole that mysteriously appeared and how devastating it is to life on Earth. It might be surprising to some that there isn’t, and has never been, a “hole.” The reference is actually to a seasonal thinning of the amount of ozone present, primarily over Antarctica and, to a lesser degree, the Arctic. A hole implies that there is no ozone present, which isn’t true. Less ozone doesn’t equate to no ozone, so it would probably be unwise to think of it as a hole.
Ozone layer
The term “ozone layer” is ambiguous at best. The layer isn’t a clearly defined area of the atmosphere and even the National Oceanographic and Atmospheric Administration (NOAA) admits that the density of ozone is small, while the layer isn’t clearly defined. It could best be described as one of several areas in the atmosphere that have increased levels of O3, the main area being several miles above the surface of the earth. Put eloquently by Cliff Mass in the book, “The Weather of the Pacific Northwest,” if all the ozone in the stratosphere was compressed into a single layer, even at sea level, it would be about one-eighth of an inch thick (about 3.2 mm).
Ozone composition
Ozone is corrosive and is toxic if large amounts are breathed in. Unlike breathable oxygen molecules, comprised of two oxygen atoms, ozone has three. This makes ozone unstable. It takes energy to cause an oxygen molecule to accept an additional atom of oxygen, in order to make ozone. However, it takes little to separate the extra atom of oxygen from an ozone molecule.
Ozone creation
Ozone can be created from the intense solar radiation present in the upper atmosphere. This energy source sometimes provides enough energy to allow an oxygen molecule to accept an additional oxygen atom. Interestingly, solar radiation can also break ozone molecules apart. This is likely to be a major reason that the seasonal thinning of the ozone occurs over the poles, during the polar summers. This demonstrates a reason ozone in the atmosphere is important. As is commonly taught in school, ozone blocks the most harmful rays of the sun by absorbing it. The absorbed energy both creates and destroys ozone.
Ozone destruction
Sunshine isn’t the only thing that disrupts ozone. Chlorine and fluorine atoms also readily bond with oxygen atoms. Substances that contain these elements, provided that they are at least several miles above Earth’s surface, can “rob” ozone of one of the oxygen atoms. This part is pretty well-known and it is the main reason that Chlorofluorocarbons, or CFC’s, are banned in many countries. They can also continue to work the damage at the molecular level.
What is less well known by many people is that there aren’t many methods for CFC’s to get several miles into the atmosphere, from the surface. Certainly, some airplanes fly at that altitude; however, surface-level atmosphere mixes with higher level atmosphere only slowly, especially at the boundary between the troposphere and the stratosphere, called the tropopause.
This said, there indeed is a mechanism for getting CFC’s and chlorine into the atmosphere to the level where ozone occurs, and it is surprisingly naturally occurring: volcanic eruption. Major eruptions can and often do send CFC’s and ammonia into the stratosphere, where the previously discussed ozone layer(s) is/are located. Often, in a rush to blame mankind, nature isn’t even considered by people when it comes to ozone destruction.
Many sites devote pages to the evil of man, and certainly more people do need to be made aware of the science behind the numbers and what it all means. However, nature has an enormous hand in both the creation and the destruction of ozone. Despite the opinions of many who believe differently, there isn’t a great deal that man can do about natural processes.
When it comes to ozone, the best first step is to understand a few of the surprising facts about the gas. There are many surprising facts about ozone, particularly in the atmosphere. A person doesn’t even need to be a science whiz in order to understand most of it.
