EMF and radiation exposure in comercial jets: For children
Hi,
BRAWM team:Thanks for the great work in telling us the numbers.
Can someone tell me the average radiation exposure in long-distance (say transatlantic) jet planes?
And any page that gives typical EMF (electro magnetic field) levels inside a jet liner cabin?
Thanks for the help.
Mom to toddler.
With a half-life of 30 years,
With a half-life of 30 years, radiocesium gives off penetrating radiation as it decays and can remain dangerous for hundreds of years. Once in the environment, it mimics potassium as it accumulates in the food chain; when it enters the human body, about 75 percent lodges in muscle tissue, including the heart. How is this at all comparable to any jet flight?
Radioisotopes and honey bees
The thing that you and the other "airplane analogy" doubters are missing in your reasoning is that radioactive atoms are basically "one-shot" devices ( or "few shot" devices for some alpha emitters). In that regard, they are like honey bees. You realize that when a honey bee stings you, the stinger pulls out of the bee's body, and that is fatal to the bee. So a given bee can only sting you ONCE.
Suppose you are going to put your arm in a box like those on the commercials for mosquito repellant. However, instead of mosquitoes in the box, there are going to be honey bees.
Let's say we have two types of honey bees. There's "airline honey bees". They are very aggressive and go right after any foreign invader like your arm. Additionally, the airline keeps feeding in more bees into the box as long as you are at altitude.
Then we have "Cesium honey bees". "Cesium honey bees" are so lethargic, that they spend most of their time sleeping. Because they spend so much time dormant, it takes on average 30 years for half of a given number of "Cesium honey bees" to find your arm and sting you.
Now we give you a choice. You can either fly on a plane for a 5 hour flight in which 20 bees per hour are introduced into the box; so you are going to come away with 100 bee stings in the 5 hour flight.
Or you can put your arm in a box with 100 "Cesium honey bees" that are going to be so lethargic, that it will take 30 years for only 50 of them to sting you.
OK - you have your choice - do you get 100 stings in 5 hours. Or do you get 50 stings in 30 years, and another 25 stings in the next 30 years. You won't live long enough for all the "Cesium honey bees" to sting you.
Additionally, that 100 stings in 5 hours for the "airline bees" may be more than your body can handle in such a short period of time, and it might kill you.
However, 50 stings in 30 years is less than 2 stings a year, or one every 6 months. Your body will have ample time to clear out the bee venom in the 6 months before you get your next sting. So the "Cesium honey bees" will not be a threat to your life. But the "airline honey bees" might be.
Do you understand now given this analogy?
Faulty Analogies and Misunderstandings
Agreed that the gun analogy is a faulty analogy. This is the reason so many misunderstand radiation risks, and don't understand the airplane analogy.
If your analogy, your mental image, of how radioactivity works is that of the gun analogy, no wonder you don't understand radiation risks. If you "think" that a radioactive atom has a little radiation machine gun and that it can shoot multiple bullets, and a long-lived radionuclide can shoot the machine gun for a long time; then you've clearly got the wrong mental image. If that's the way radioactivity worked, then of course long lived radionuclides would be the most dangerous, and you would doubt the airplane analogy.
But that's because the gun analogy is such a dismally poor analogy. The gun analogy lacks the key feature for understanding radiation; which is that a radioactive atom is a one shot ( or at most a few shot ) device.
In that regard, the honey bee analogy is quite apt. Because honey bees lose their stingers and die, honey bees are "one shot" stingers, and are an apt analogy for radioactivity, unlike the gun analogy.
If you have a long lived radionuclide, like Cesium-137 with a 30 year half-life; the only way for the radionuclide to be so long lived is to not emit radiation very often. For a 30 year half-life, the average time a radioactive atom waits before emitting radiation is the half-life divided by the natural logarithm of 2 ( i.e. the inverse of the decay constant ). For Cesium-137, with a 30 year half-life, the mean time to emit radiation is about 43 years. The "Cesium honey bee" on average takes 43 years before she stings someone.
If the honey bees are going to have a chance of killing you or doing a lot of damage with their venom; then they all have to attack in a short period of time. That's what the "airline honey bees" do in the above analogy. Since the "airline honey bees" all sting you in short order, that maximizes the amount of bee venom in you, and that may be more than your body's defenses can cope with.
However, since "Cesium honey bees" only sting at long intervals, your body has the opportunity to destroy and flush out the bee venom. You never have more than a little bee venom in your system, so you are in no danger of being killed by the "Cesium honey bees".
Likewise, when you have a long-lived radionuclide; your body's DNA radiation damage repair mechanism has ample opportunity to repair the damage the radiation has done, so it minimizes the amount of damage to your system.
So the honey bee analogy contains the key features needed to understand radiation damage. The gun analogy doesn't have these feature, and thus is a dismally poor analogy.
Radioactivity and AIDS
Another problem with the gun analogy is that a hit from a single bullet has a high probability of being fatal.
Radiation isn't like that either. A hit by a single photon doesn't have a high probability of giving you cancer. In fact, a mutation that results in a cancer is actually a very rare event in terms of a single radiation "hit". Much more likely is that the radiation will simply kill the cell. Your body now has a dead cell to dispose of; but that's hardly new. You body disposes of lots of dead cells that died naturally. A dead cell is not a threat to you as an organism.
The only real threat to you as an organism is the initiation of a cancer. The anti-nukes and the Helen Caldicott followers would have you believe that a single hit from radiation is a 100% chance of developing a cancer. Far, far, from it.
These types remind me of the wackos in the early days of the AIDS epidemic. They tried to sell the public on the hypothesis that a single HIV virus was enough to grow and infect you, and give you AIDS. Because if was shown that HIV virus was shed in the sweat and tears of those infected with HIV; then "casual contact" with a person who was HIV-positive was a way of getting infected with that single HIV virus that would give you AIDS.
Of course, we all know now that "casual contact" with an HIV-positive person is not how you get AIDS. The people who were attempting to get the public to buy into that argument were NOT attempting to give the public good medical information. NO - they had a political agenda. They were just trying to stigmatize gays. What better way to stigmatize gays than to get people to fear them due to the possibility of an AIDS infection.
Likewise, those that peddle gun analogies, and fear-monger about radiation, are NOT attempting to give the public good scientific information. Just like the homophobes; they are attempting to scare people as a way of furthering their parochial political agenda.
I prefer the loaded gun
I prefer the loaded gun analogy.
In that one every unstable atom is a loaded gun that will go off at some random time in some random direction and the bullet is the ionizing radiation, leaving a trail of destruction as it traverses the body. Each gun has only one bullet and once it goes off it's done.
So bullets flying at you from outside penetrating the body is not much different from having some of these loaded guns going off inside you.
So comparing X bullets per second hitting you from cosmic rays on an airplane versus X bullets per second from loaded guns going off inside you is completely comparable.
Half-life is then a measure of how often a gun will go off.
Short half-life means that there's a hail of bullets flying around but the loaded guns are quickly used up and then it's done.
Long half-life means that guns only go off infrequently but that means it's going to take a long time before they're all used up.
Lastly, there are three different types of bullets: alpha, beta and gamma that behave differently and cause different levels of damage.
Faulty analogy
The above analogy is blatantly faulty A single bullet can kill a person, and then go right on thru and kill another person....
Radiation is not like that.
Additionally, there is a background level of radiation that we are all exposed to that is not killing us. Is there a background level of flying bullets that is not harming us?
I thought not.
Radiation is like that
Cancer begins in one damaged cell. It is a well known fact that radiation causes cancer.
It is also a well know fact that radiation causes birth defects. A bullet that goes through one person and hits another causing harm.
WRONG!!!! WRONG!!! WRONG!!!
Evidently you don't understand the physical mechanism by which these damages are done. It is NOT like a bullet that passes through an object, does damage, and leaves to do more damage.
Why don't you study the science of radiation interaction with matter - things like photoelectric effect, positron-electron pair production...
Correct
You are correct. The poster with the bee analogy had the best take on this. With a bee, the bee stings you, leaves the stinger in place, and then the bee dies. This is the closest analogy to what happens with radiation. The gun / bullet analogy is not a very good analogy for either radiation or bees. Bees don't sting, then go on to sting another person, and then on to another person... A bullet can do that, which makes the bullet much more dangerous. That's probably what the originator of the bullet analogy was attempting to do; find an analogy that maximizes the amount of damage. Unfortunately, this poster didn't consider that the analogy was very poor. The traits of radiation are better mimicked by the bee analogy than by a bullet analogy.
Excellent Analogy!!!
This is an excellent analogy. I hope this analogy helps people better understand the issues raised. I know I will be using this analogy in the classes I teach.
EASY
Easily compared to jet flight.
Once the given amount of Cesium-137 accumulates in the heart; you take the total radioactivity of that is in the heart. That radioactivity level will equal the decay constant for Cesium-137 ( natural logarithm of 2 divided by the 30 year half-life) times the total number of atoms of Cesium-137.
So if you divide the radioactivity by the decay constant; you get the total number of radioactive atoms, and hence the total number of radioactive decays for that amount of Cesium.
There is a given energy for each of those decays, and we then assume that energy is deposited in the heart muscle. If you multiply the number of total possible radioactive decays by the energy per decay; you get the total amount of energy deposited in the heart muscle. If you divide by the mass of the heart; you get the dose.
Now when you fly in an airliner, you are being bombarded by cosmic rays; and those cosmic rays are depositing energy in your heart muscle.
We then compare the amount of energy that is deposited by the cosmic rays during the course of the airline flight to the total amount of energy that the Cesium can deposit, which is called "committed dose".
Additionally, it will take a few hundred years for all the Cesium to release its entire complement of energy; and the person will long be dead.
If the values for the energy deposition for airliner travel and internal Cesium were the same number; the airliner exposure would be WORSE for you. That's because you would actually get that amount of energy deposited in your heart in the few hours of the airliner flight. Because you are going to die before all the energy comes out of the Cesium; the internal exposure due to Cesium is actually going to be LESS than for a numerically identical dose due to cosmic rays in the airliners.
For a given dose; the exposure due to cosmic rays in the airliner will always be WORSE that internal exposure that is metered out over time. The longer exposure time for the internal dose also gives the body's DNA repair mechanism more time to repair any radiation damage. For low enough internal exposure rate, you won't get ANY damage because the DNA repair mechanism is able to "keep up" with the rate at which damage is done.
Cosmic ray exposures in airliners take place too fast for the DNA repair mechanism to "keep up".
Only when the last tree has
Only when the last tree has withered, the last fish has been caught, and the last river has been poisoned, will you realize you cannot eat money. In our every deliberation we must consider the impact of our decisions on the next seven generations.
Nuclear power and it's
Nuclear power and it's attendant problems, are the biggest existential threat to the survival of every living species on the planet, plant and animal.
Birds are a bigger threat than radiation
Birds are a bigger threat to your safety in an airliner than is radiation.
There are thousands of bird strikes each year. Many are small birds like those that hit Air Force 2 with VP Biden, and also a plane carrying Sec of State Clinton.
Then there are larger birds or flocks, like the ones that disabled one of the two engines of a Delta Boeing 757 taking off from New York. Engineers plan for such occurrences and a Boeing 757 can take off and fly with only one engine.
Only in rarely do the birds disable both engines like the Airbus flown out of New York by Capt. Sullenberger who had to ditch the airliner in the Hudson River.
However, we readily accept such risks as part of the "cost" of flying.
I wonder why the much more benign radiation exposure is not seen in a similar light.
Risk vs benign radiation exposure
What about some of the unprofessed radiation externalities of air flight?
The first issue is that the flights are quite often round trip so shouldn't the radiation comparison express this.
The second issue is that of passing through a body scanner coming and going, these doses of radiation should also be taken into consideration.
Thirdly is the issue of EMF from numerous wireless devices indiscriminately being used throughout the terminal, in addition numerous food establishments all using microwaves ovens; add to this the long check-in and waiting for the flight compounding the EMF exposure coming and going.
All these risk factors should be part of the decision to fly, which is a choice some people make.
Conversely what you refer to as "benign radiation exposure" is not a personal choice.
It would seem that if these externalities were factored in, the real life airplane anthology is much more flawed than expressed by the often referenced apples for apples statement.
Opposite conclusion
Actually, if you factor in the external factors that you cite; it makes air travel even more risky in terms of radiation exposure. That, if anything, strengthens the airplane analogy.
We accept air travel and its attendant radiation exposure, which is even worse if you factor in the external factors you cite.
If we accept air travel that is even worse in terms of radiation exposure; why do so many people have trouble with accepting the lesser risks from nuclear power?
From the Health Physics Societ regarding EMF
The Health Physics Society has this to say about exposure to the EMF from power lines. Any exposure to EMF in a jet will be low voltage exposure and WAY WAY less than what a power line emits:
http://hps.org/hpspublications/articles/powerlines.html
In 1995, the American Physical Society (APS) spoke out on the question of power-line EMFs and health effects. The APS policy statement reads, in part: "The scientific literature and the reports of reviews by other panels show no consistent, significant link between cancer and power line fields. While it is impossible to prove that no deleterious health effects occur from exposure to any environmental factor, it is necessary to demonstrate a consistent, significant, and causal relationship before one can conclude that such effects do occur. From this standpoint, the conjectures relating cancer to power line fields have not been scientifically substantiated." (See APS Policy Statement 95.2 reaffirmed in 2005.)
From the Health Physics Society
Form the Health Physics Society:
http://hps.org/publicinformation/ate/faqs/commercialflights.html
The average effective dose rate of all flights of Xinjiang Airlines from 1997 to 1999 was 0.238 mrem (millirem) per hour.
So the rule of thumb is about a quarter mrem per hour of flying time.
If you have a four hour airline flight; you get about 1 mrem of radiation exposure which is about 1 entire days worth at sea level. So you get almost 2 mrem for that day total.