Monday, December 22, 2014

Comparing Aviation and Nuclear Power's Safety Record for 2014

It often seems like people zero in on the dangers of certain things while largely ignoring the dangers of others.  For example commercial airlines.  People are often more afraid of flying then they are of driving, and if they've been watching the news this year they would probably feel justified in their fears as this year has seen news story after news story about downed and missing airliners, but things are not always as they appear to be.   In 2014 761 people died on commercial airlines world wide while a staggering 33,783 people died in automotive accidents in the US alone.  Things can look a lot different when you compare statistic than they do when you just go by gut feeling, or what makes the news more often.  Often people consider nuclear power to be dangerous.  Far more dangerous then flying, but I wonder if that's really the case.  That's why I'd like to try and compare Aviation and Nuclear Power safety record for 2014.

Accidental Deaths 

The first comparison is talking about the number of people directly killed as a result of the different activities.  This comparison doesn't deal with radiation.  That's up next. 

Well we got 761 death for commercial aviation.

Nuclear Power
Three people died in and industrial accident while constructing a nuclear reactor.  They most likely died of asphyxiation from breath pure nitrogen gas.  Nitrogen gas is sometimes used in construction

761 is much larger then 3.  Point 1 goes to nuclear.

Radiation Exposure 

This section is for comparing radiation exposures between the two activities.  Some useful information: 1,000 nSv = 1 µSv,  1,000 µSv = 1 mSv, and 1,000 mSv = 1Sv.  Sv stands for Sievert which is a unit used to measure the effect of low levels of ionizing radiation on the human body

Lets start with commercial aviation.  On commercial airlines people are exposed to higher the normal levels of ionizing radiation because of their altitude.  Basically there's ionizing radiation coming from space (i.e. cosmic radiation).  A lot of it gets blocked by our atmosphere, but not all of it, and when you higher you receive large doses (also being closer to the equator gets you higher dosages).  So lets try and calculating how much radiation exposure results from air traffic.

According to the FAA Revenue Passenger Miles (An RPM represents one paying passenger travelling one mile) where 815 billion in 2011 and expected to be 1.57 trillion in 2032.  That's as close as I could get to 2014 with my Google skills, but It probably hasn't changed that much in three years so I'll just go with it. I couldn’t find information on total hours passenger spent travelled so but a commercial jet travels between 500 to 900 km/hr.  With that and a little math we get 1.46 to 2.62 billion total hours flown by paying customers in 2011, and a projected 2.81 to 5.05 billion total hours flown by paying customers in 2032. 

That is a lot of hours. Next lets look at what people are exposed to during those hours. The amount of radiation people are exposed to during flight depends on both altitude and latitude, so in order to get a better idea of the rate of exposure people can reasonably expect during commercial flights lets look at some data taken from Xinjiang Airlines.

Feng YJ, Chen WR, Sun TP, Duan SY, Jia BS, Zhang HL. Estimated cosmic radiation doses for flight personnel. Space Med Med Eng 15(4):265–269; 2002.
  • The average effective dose rate of all flights of Xinjiang Airlines from 1997 to 1999 was 2.38 µSv h-1.
  • The average annual cosmic radiation dose for flight personnel was 2.19 mSv.
  • Annual individual doses of all monitored flight personnel are well below the limit of 20 mSv y-1 recommended by the International Commission on Radiological Protection (ICRP).
Now we need to know the average world wide natural background radiation so we know how much more people get while flying.  Using Wikipedia I got this 0.27 µSv/h (Derived from 2.4 mSv a year) So with a bit of subtraction I get 2.11µSv/h (2.38 - 0.27 = 2.11) more radiation from flying.  Using this we have 1.46 Gh to 2.62 Gh times 2.11 µSv which equals 3,100 Sv (3,080,600,000 µSv) to 5,500 Sv (5,528,200,000 µSv).  If you applied Linear No-Threshold Model to that it would equal 155 to 275 extra cases of cancer for one year of commercial flight, projected to almost double by 2032.  To put that number in perspective this study estimates a total of 130 fatal cancers as a result of the Fukushima nuclear accident.  Though some people contest the validity of applying the Linear No-Threshold Model to low levels of exposure. 

I looked for information about military aviation exposure, but couldn't find anything so I'll leave that out.  I'm also leaving out commercial pilots.  They fly aircraft for other reasons, such as charter flights, rescue operations, firefighting, aerial photography, and aerial application, also known as crop dusting.  I have no clue what kinds of does they get.  For things like crop dusting I'm guessing not a lot. 

For information about flight attendants and pilot.  I was able to get some employment numbers.  There were  84,800 jobs for flight attendants, and for airline pilots there were  66,760 (104,100 - 37,340 = 66,760) job.  From the study quoted above we get 2.19 mSv does for flight personnel each year so that adds another 330 Sv (331916.4 mSv = 2.19 mSv (66760+84800)). 

Next lets talk about space.  Do to the lack of atmosphere astronauts get higher dosage than most professions do.  So lets try and calculate that.  The international space station has six crew spots and they've been filled all year round.  I've found this information about their doses.

The green line is the one that matters to us.

The number on the left are for annual mSv.  The number one the bottoms describe aluminium shielding with 0 being zero shielding and 100 being the most shielding.  Looking at the green line, at solar minimum it looks like they get up to 225 mSv  unshielded, and down to around 75 mSv shielded by aluminium.  I'm just going to assume they're shielded most of the time and call it 100 mSv a year.  There are 6 people on the station all year round so we end up with 600 mSv.

All together for aviation 2014 we get between 3,430.6 Sv to 5,830.6 Sv.  There are a lot of things I've left out like solar particle events, but given my limited resources and waning patience this will have to do.

Nuclear Power  
When you think nuclear and radiation the first thing on a lot of people's minds these days seems to be Fukushima.   So I did some searching and found one map that shows up to date radiation readings, and the other map shows the current evacuated areas.  Here are the two maps side by side at roughly the same scale (I think).

I find these maps rather interesting in light of what I've learned about aviation.   Consider 2.38 µSv/h the the average does for airlines that I used above.   If I wrote this like the radiation readings map it would be 2,380 nSv/h, and would be accompanied by an ominous red dot.  It becomes even more interesting when you consider that 2.38 is just an average. Depending on the type of flight exposure can be much higher.  From an earlier link
Friedberg W, Copeland K, Duke FE, O'Brien K 3rd, Darden EB Jr. Radiation exposure during air travel: Guidance provided by the FAA for air carrier crews. Health Phys 79(5):591–595; 2000.
  • Seattle to Portland: 0.03 mSv per 100 block hours
  • New York to Chicago: 0.39 mSv per 100 block hours
  • Los Angeles to Honolulu: 0.26 mSv per 100 block hours
  • London to New York: 0.51 mSv per 100 block hours
  • Athens to New York: 0.63 mSv per 100 block hours
  • Tokyo to New York: 0.55 mSv per 100 block hours
On the first map a flight from Athens to New York would be listed as 6,300 nSv/h. Furthermore the space station data from Nasa would get purple dots with the heights level of shielding getting 8,560 nSv/h, and no shielding getting 25,700(much higher than anything on the Fukushima map). I find it ironic that people can get on a plane and travel halfway around the world, or even go to space, while thousands of Japanese people aren't even allowed to travel the handful of miles needed to see their own homes.

Unfortunately while this investigation was interesting to me it didn't really give me an idea of what doses people are getting because of Fukushima. I was starting to worry that I would ever get the information I need but luckily Wikipedia came to my rescue again (The same page even). From that article I got an average of 0.0002 mSv a year exposure worldwide. Knowing that there are around 7.3 billion people on earth we can do a little math and get 1,460 Sv ((7,300,000,000 * .0002)/1000 = 1,460) a year exposure from nuclear power.

With between between 3,430.6 Sv to 5,830.6 Sv. from aviation  and 1,460 Sv from nuclear power.  Point 2 goes to nuclear. What an upset victory! 

Terrorist Threat

Terrorist threats are on a lot of people minds these day.  People keep worrying about what they might be up to next. So the question this time is what is more vulnerable to terrorist attacks.  Nuclear power plants or aviation.  Something like this is really hard to put a number on.  Luckily Wikipedia came to my rescue again with the List of terrorist incidents in 2014.  I'm just going to add up all the ones that had to do with nuclear power or aviation.  The one that gets the least wins.

Aviation has a bit of history of terrorism with the whole Twin Towers thing.  Lets see how it fared this year. 

Car bomb
A remote control car bomb exploded near the international airport in Mogadishu as a convoy of U.N vehicles traveled by, damaging one of the U.N vehicles, killing seven Somali civilians and injuring 15 civilians and four security guards. No U.N. Somali or International staff were injured or killed in the terrorist attack.[68][69]
Al Shabab
14 (+10 terrorists)
Gunmen stormed Jinnah International Airport, killing 24 people and injuring 14 others.[160]
Taliban fighters fired eight rockets at a Jalalabad NATO air base. No casualties or property damage were reported.[181]
Suicide bombing, shootout, raid
Assailants conducted a series of attacks in the Seiyun, Yemen. In one attack a suicide bomber drove an explosive-laden vehicle into the entrance of an army base, killing four soldiers. In another attack, non-state militants attempted to raid Seiyun's airport, killing two soldiers. The government killed four militants in order to regain control of the airport. In another attack, a civilian woman was killed by an agricultural plant.[19

Nuclear Power

There wasn't any.


Nuclear wins again.  There are a lot of things about airports that make them good targets.  For example lots of people going in and out leaving holes in security.  Also, they often exist in places that have a lot of terrorists making them conveniently located targets for them to lash out at the 'evil' foreigners.  

The Dangers of War   

I'm not really sure that this is comparison is really needed, but people often argue that nuclear power is a nuclear weapons proliferation threat so I figured I better at least mention it.  My own view is that technical advancement of any kind is a nuclear proliferation threat.  If you want to keep someone from getting nuclear weapons you have to basically keep them down so that they can not make anything that can threaten you.  Such a practice is unethical in my opinion, and counter productive because poor miserable people are more likely to be violent.  Really instead of holding some people down I think we should bring everyone up so that we can all enjoy the fruits of technological progress together.  Then I think the world would be a much safer friendlier place.  In the end I declare this category a tie because I can not quantify this in any way that I find meaningful.

Final Conclusion

Nuclear wins!

Whether or not this article changes your mind about anything I hope you enjoyed it, and it at least made you think. 




  1. "1,000 nSv = 1 µSv, 1,000 µSv = 1 mSv, and 1,00 mSv = 1Sv. Sv stands for Sievert which is a unit used to measure the effect of low levels of ionizing radiation on the human body"

    Did you mean to say 1,000 mSv = 1Sv ?? I think you missed a zero.

    1. Your right I missed a zero. Thanks for pointing it out.

  2. This is an interesting overall comparison for one year. I don't think that many will be persuaded by it since most who are skeptical of Nuclear can point to the 3 big accidents and they believe that these show thousands to millions of deaths. There is also the point that we accept more risk when we choose the risk than when someone else is imposing it on us, (or at least appears to be imposing it on us).

    So the question is, how do we show people that Nuclear is essentially NOT imposing a health risk of any kind?

    Secondly, there is the property thing. Even though there is minor or NO health risk people feel more badly about loosing property than about loosing a loved one. The evacuations cause more fear than the cancer, in my opinion.

    I think you are on there right track, keep publishing!