What Is Radiation?
Where does it come from? How can it hurt you? How can we avoid it? Quick and Dirty Tips' newest expert, Everyday Einstein, answers these and many other questions about radiation.
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The Currency of Radiation
Let’s pretend that the laws of the universe have rearranged themselves so that every time you’re exposed to radiation, you also earn some money. In this new and profitable universe we’ll say that 1 Sv of radiation is worth $1,000.
If the average person earns $100 in radiation money in a short time period, their blood chemistry will start to be affected; at around $500 they’ll start to experience nausea and vomiting; and at somewhere between $800 - $1,000 they’ll start to see hair loss and internal hemorrhaging. A payout of $4,000 or higher is typically fatal.
There is no way to shield your body from all forms of radiation. Even if you live in an underground box made of lead, living off tofu and distilled water, your body will still experience radiation. Every day you are bombarded with cosmic radiation from space, radiation from radon in the ground, and radiation that occurs naturally inside of your body. Depending on where you live and whom you ask, you will earn about $2.00 - $3.00 in radiation money each year from this natural background radiation.
“Ah,” I hear you asking, “but what about X-rays, mammograms, MRIs, and CT scans? Surely all that radiation does more harm than good! These doctors are trying to kill me!”
Continuing with our monetary analogy, the average chest X-ray adds only $0.02 to your annual total, mammograms have about twenty times the exposure, which is still only $0.40, and MRIs don’t expose you to ionizing radiation at all. Radiation from CT scans varies depending on the type, but the average cranial CT scan earns you about $2.00 in radiation money.
What About Cancer?
These numbers only deal with acute radiation poisoning. What about the long term risk of cancer caused by radiation exposure? According to the EPA, an average of 2,000 out of every 10,000 adults will die from some form of cancer. If you expose everyone in that group to an extra $10.00 of radiation in one year, the number will jump to about 2,005 people. This is why X-ray technicians hide behind a wall while giving you an X-ray, since they may have to administer thousands of exams every year, whereas you may only experience a handful.
What About Fukushima?
It’s still a little early to know the exact effects of the Fukushima disaster. Understandably, everyone in Japan now seems to own a personal Geiger counter. Unfortunately this has led to some contradictory information circulating in the media.
More trustworthy reports of recent measurements (taken on August 13th, 2011) show that the area around Fukushima itself was experiencing around $0.06 worth of radiation every hour. One village 20 km to the northwest of Fukushima (where the fallout was particularly heavy) reported $0.03 worth of radiation every hour. So while the residents in and around Fukushima are certainly at risk from elevated levels of radiation, those further away (like residents of California) have little to worry about.
Until next time, I’m Everyday Einstein, with Quick and Dirty tips for Making Sense of Science.
Here are some additional resources to help you learn more about radiation levels:
A great infographic showing relative radiation levels from different sources: http://xkcd.com/radiation/
An online radiation dose calculator from the EPA to help you estimate your average annual radiation dose: http://epa.gov/radiation/understand/calculate.html
FA Mettler, Jr et al. Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog Radiology July 2008 248:254-263
Warning sign image courtesy of Shutterstock.