Category Archives: Background Information

Examples of Radiation Doses

There are many units used to measure radiation.  I will be using the units called micro-Seiverts (which is techno-geek for 1 millionth of a Seivert and is abbreviated “uSv“).  The unit is written with a greek letter “mu” (which translates to the letter “m”).  Since there is no Greek on my keyboard I’m going to use the letter “u”, which sort of looks like “mu”.  Why don’t I use an actual “m”?  Because that actually stands for milli-Seivert.  A milli-Seivert is one thousandth of a Seivert or 1000 micro-Seiverts.

Sorry, if some of you know all this already.  I’m writing this for aircrew and frequent flyers, and most don’t know this stuff.  So let me explain it a little…

A Seivert is a unit of radiation used to measure the absorption of radiation in human flesh.  Seems apt.  And it’s popular in this moment of time.  Also, my gamma ray detector uses the Seivert (Sv).  So I’m going to use it.

The chart below can be found on Wikipedia.  Click on it and you’ll go to the full, zoomed view.  It’s a great way to compare radiation exposure from everything from bananas to Fukijima.  What I’d like you to notice, though, is that  it shows the NORMAL YEARLY BACKGROUND DOSE as 4,000 uSv.  This is the baseline that I’m going to use.  In the short time I’ve been using my radiation detector, I’ve noticed that ground levels of radiation in North Carolina (.09 uSV) and also Dallas, Texas (.06uSv), are extremely low…almost zero.   I’m going to set my radiation detector up so that it will go orange if levels will cause the cumulative dose to go above 4000 uSv per year.

Radiation exposure is cumulative!  Apparently the body doesn’t recover from being hit by gamma rays.  They add up over a lifetime.  You could take 4 million bullets and throw them (not shoot) at someone and it’s not going to add up to one bullet shot at a velocity of 1200 ft per second.  But you can throw radiation at a person and when it reaches 4 million micro-Seiverts the person will likely die.  Radiation is cumulative.  If you get a heavy dose one year, it’s best to get that time back another year, by staying in low radiation areas.

And this is where my concern for fellow aviators comes into play.  We fly at high altitude for many hours year after year.  Obviously we aren’t getting lethal doses or we’d all die.  But does it have lesser affects on us that we only notice when we start getting on in years?  Well, before we get into the health effects, let’s get some actual numbers.Radiation Dosage Chart

Are radiation levels at high altitudes dangerous?

My interest in radiation at high altitude is to find out, for myself, exactly what the levels of in-flight radiation are.  Are they dangerous?  Should we take an interest in them?  Should aircrew and frequent flyers be concerned?  Or are they low enough as to not cause a worry.  I’m no rabble-rouser and so I would be delighted if I find that radiation in flight is nothing to be concerned about.  If so, this will be a very short blog.  However, if the radiation levels seem pretty high, then I’ll delve into ways your own radiation exposure (and mine too!) can be mitigated over the long run.  Perhaps a healthy person will not suffer from radiation as much as someone who’s unhealthy.  Who knows?  I’m going to figure all this out.

I am a Gulfstream pilot and I fly all over the world.  My aircraft can go as high as 45,000’ so it’s going to be a good plane to get some good data.

Polimaster, maker of radiation detectors, has given me a slick gadget that connects to an iPhone or iPad and reads gamma radiation.  It’s called the Polismart II (model 1904) and It’s a brand new product for them.  I’m helping them beta test it, so this blog will also be attached to their website.

I fly between 500 and 800 hours a year.  I’m not an airline pilot, I’m a corporate pilot (I fly the rich guys) so I probably don’t fly as much as the airline guys.  Some of those guys can approach 1000 hours a year in the cockpit.  And let’s not forget that a lot of them spend a lot of time in the back, commuting to and from work.  This blog is really for them and the frequent flyers they fly.  The flight attendants, pilots and frequent flyers, flying short and long-haul routes, around the world, should know about in-flight radiation levels.  According to some, they receive more radiation, on the job, than in any other industry.  That may sound shocking, but let’s just wait and see.  I’m going to get some solid numbers and maybe I’ll find out that it’s really not that bad.

So, if you’re interested, stay tuned and let me start doing some trips with my new radiation detector.  I’ll be posting the numbers and the iPhone screen shots from my trips.  No matter if the numbers are high or low, I’ll post them.  And you can have the same data that I’m getting and can draw your own conclusions.

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My vehicle for testing high altitude radiation

My vehicle for testing high altitude radiation

This is the Gulfstream IV. Thanks to my new Polimaster gamma radiation detector I’ll be able to see what the actual gamma radiation levels are in flight.