You have been living a dangerous life on daily basis without
even realizing it. You inhale polluted air mixed with your friend’s bad breath,
eat hamburgers cooked by a chef with dandruff problems on his mustache, drive
under the influence of heavy metal music, and wear thongs while exercising. It
all sounds very dangerous, but they are nothing compared to UV radiation from
the sun; either that or the lack of Internet connection. While one the most
common causes of a disconnected Internet is the fact that you forget to pay the
bill, UV radiation is a persistent risk of living preventable only by the
existence of Ozone layer.
Ozone is somewhere around and circling the Earth, definitely |
Earth is the most habitable planet in the solar system because
of two major reasons:
- The planet provides useful stuffs that all living creatures need such as air, carbon, water, and terrestrial television. It does not give you money, but you can earn revenues by selling photographs of the Earth to NASA and Garmin.
- Everything on Earth is well-insulated by atmosphere, so the temperature on the surface is neither too cold nor too warm. Some places are indeed extremely cold but it is not impossible for human to live there, albeit temporarily. For more information on this, feel free to visit the North Pole.
Atmosphere does three main functions: it keeps the Earth’s
surface warm enough, provides oxygen, and protects everything beneath it from
UV radiation generated by the sun. Major portions of the atmosphere are
comprised of nitrogen and oxygen or the air you breathe. Both gases, however,
cannot retain heat but fortunately the atmosphere also has what it takes to do
the job; it is called greenhouse gases which include carbon dioxide, nitrous
oxide, water vapor, methane, and ozone. Too much of those cause something that
everybody calls global warming.
Ozone is one of greenhouse gases, which retains heat, but it
multitasks as a protective layer to block ultraviolet radiation. Unless you
skip chemistry class far too often to find Pokemon, you should know that the
chemical formula for Ozone is O3 so it consists of three Oxygen atoms. Based on
that definition, Ozone is actually just a special form of Oxygen.
Where is Ozone?
Earth’s atmosphere has 6 layers and is comprised of 78%
nitrogen, 21% oxygen; the remaining 1% consists of many things which may
include water vapor, dust particles, bacteria from your mouth, and everything
that comes out of cars’ exhaust pipes. Both troposphere (the lowest atmospheric
layer) and stratosphere (the second lowest atmospheric layer) have ozone.
In the stratosphere, Ozone is formed when an Oxygen molecule
(O2) is broken apart by ultraviolet radiation; the result is two Oxygen atoms
that no longer bind together. Each of the atoms is highly reactive and actively
seeking for new partners. Every time an atom successfully binds an Oxygen
molecule, Ozone is produced. Ozone does protect Earth from harmful UV
radiation, but it forms thanks to the radiation in the first place. The process
is pretty much like a divorce, but without the subpoena and custody issues.
In the troposphere, chemical reactions which primarily
involve pollutant gases from fossil fuel combustion can also produce ozone.
Sunlight is required to complete the process. As soon as tropospheric ozone
reacts with surfaces of plants or soil, however, they are destroyed.
How Does Ozone Block
UV Radiation?
In many scientific books for children, you will read that
Ozone blocks UV radiations. This is neither entirely wrong nor totally
accurate. Don’t blame the book – the writer is still smarter than you. What
really protects you from getting sunburn and immune system suppression due to
UV radiation is the relentless Ozone-Oxygen production cycle that happens in
three stages:
- When UV light reaches the stratosphere, it reacts with Oxygen molecule (O2) and breaks the bond. The separation of Oxygen molecule into two Oxygen atoms consumes the energy generated by the UV light.
- The resulting two Oxygen atoms bind themselves with two Oxygen molecules. These reactions produce two Ozone molecules.
- The remaining energy generated by UV light is then utilized to break down O3.
As all three stages are completed, UV light only has about
2% of energy that reaches Earth’s surface. In other words, the Ozone helps
eliminate the dangerous effects of harmful radiation by 98%. It is worth
mentioning that only the short-wavelength UV light is affected by Ozone.
Long-wavelength radiations do reach the Earth but they are much less harmful
than their shorter counterparts.