Not all types of radiation are
created equal. This means that depending on its origin, radiation can be fairly
benign or incredibly malignant. Many natural sources exist, such as sunlight,
rocks, soil and food. There are also plenty of human-derived emitters, such as
airport security screeners, medical procedures like X-rays, cell phones and
nuclear weapons.
"We're all exposed to radiation
on a daily basis," explains Kelly Classic, a radiation physicist at the Mayo Clinin, and public outreach coordinator
for the Health Physics Society - noting that small amounts of
radiation can be found in fertilizers, some soils, building materials and even
bananas, because of their naturally occurring potassium. "It's something
that we live with every day and so rarely question it."
All forms of radiation, whether from
sunlight or a computer, operate on the electromagnetic scale - each with its
own, varying frequency, wavelength and energy emitted. Depending on the amount
of energy they have, the wavelengths can travel certain distances and penetrate
certain objects. Longer wavelengths, like those used in cell phones, garage
door transmitters and AM/FM radios, have lower energies and lack the ability to
cause changes to atoms. People are exposed to low-intensity radiation
throughout each day, giving it the name background radiation exposure.
Most people in the U.S. are exposed to about 3 millisieverts (mSv) worth of
natural radiation each year, an amount that is presumed harmless. The mSv is a measure of the amount of
radiation absorbed by the human body.
It's when one adds higher intensity
radiation to this everyday exposure that health concerns begin. As wavelengths
become shorter, their energy intensity continues to increase until it becomes
ionizing, or causes changes to the cellular structure of atoms. Ionizing radiation is the most powerful form of radiation
is, and it can be used to produce electricity, treat cancer, take X-rays and sterilize medical instruments.
Ionizing radiation is more worrisome, especially when unborn babies come into
contact with it, since it can have serious health ramifications.
(health.howstuffworks.com)
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