................................................................................................................................................................
Aviation And Cosmic Radiation
Does Flying In Airplanes Expose Us To Cosmic Radiation Risk?
Hussain Kanchwala
Traveling by air these days is very common, whether you
are flying for an important business meeting or just a leisurely trip to a
holiday spot.
However, frequent flyers are often unaware of the perils of cosmic
radiation arising from colliding stars, supernovae and other cosmological
phenomena that become much more prevalent as flyers soar miles and miles
above the Earth.
Cosmic Radiation
High- and low-energy particles (usually made of protons and helium
nuclei) from the sun (solar radiation) and other cosmological phenomena
(galactic radiation) are constantly bombarding Earth.
Collectively, these forms of radiation are called cosmic
radiation. Millisieverts is the unit used for measuring cosmic radiation
absorbed by humans.
Thankfully, most of the cosmic radiation is soaked up or deflected
by the Earth’s atmosphere.
However, as the dynamics of altitude and latitude are altered when
we fly above Earth, the resistance offered by the atmosphere to cosmic
radiation diminishes.
When you travel in an airplane at high altitudes, you
cannot see those highly-charged radiated particles, but at any given instant,
thousands of them are flinging through space and may slam into the Earth’s
atmosphere.
Another
radiation hazard associated with flying high above sea level in a plane is
exposure to the occasional energetic outburst from the sun.
This radiation includes exposure to X-rays and gamma
rays from solar flares, and potential scuds of high-energy protons.
Earth’s atmosphere and magnetic field protect us and
other living organisms from most of these harmful rays.
Astronauts face the most extreme risk, as they travel
completely away from the Earth’s atmosphere and are completely
without its protective shielding.
Thus, they are bound to receive high doses of cosmic
radiation.
The maximum length of manned space flights is often
limited, due to the amount of radiation the astronauts are likely to
absorb.
A prolonged space flight increases a number of
health risks, such as cancer and heart ailments, when they return back home.
Indeed, radiation exposure is also a major challenge
for ambitious entrepreneur Elon Musk before he can realize his dream of
colonizing Mars.
As the Martian atmosphere is pretty thin, a
prolonged stay there is likely to turn fatal due to high exposure to cosmic
radiation.
Three Factors That Affect Radiation
Now that you know that traveling in an
airplane exposes you to low levels of cosmic radiation, let’s now look into
three important factors that control the dosage or intensity of this radiation.
1. Flight Duration
The longer you’re on a flight, the higher the
dosage of exposed cosmic radiation. You will be exposed to roughly 0.03
millisieverts of cosmic radiation if you fly from Washington to Los Angeles.
This amount of radiation is less than the
radiation you would be exposed to when undergoing a chest X-ray.
2. Altitude
Altitude is the second important decisive
factor for cosmic radiation exposure. Altitude is the measure of height from
sea level.
The higher you go, as is the case with flying
on an airplane, the dosage of cosmic radiation increases.
This is because as we traverse higher, the
air becomes thinner, so its shielding ability to ward off cosmic radiation
through deflection decreases substantially.
3. Latitude
Latitude is another important parameter that
affects the dosage of cosmic radiation.
Latitude is the (angular) distance from the
Earth’s equator. The farther north or south you are from the Equator, the more
radiation you’re likely to receive.
This disparity of radiation dosage is due to
Earth’s magnetic field.
At the equator, Earth’s magnetic field
deflects the cosmic radiation away from the equator towards the north and south
poles.
Aviation – a Risky business
The Federal Aviation Administration has
classified pilots and flight attendants as radiation workers since the early
90s.
Shockingly, a report published by the
National Council on Radiation Protection and Measurements noted that air crews
receive the highest annual dosage of radiation, meaning that air crews are more
susceptible to radiation than the workers in nuclear reactors!
Health Risks Associated with Cosmic Radiation
Some researchers have tried to establish a
link between cosmic radiation and health impairments, especially cancer.
However, attempts to link doses of ionizing
radiation to demonstrable health risk is not simple and straightforward.
A group of Scandinavian researchers conducted
an intense study for 17 years on thousands of male pilots to establish a link
between radiation and health ailments.
The study found that the risk of developing
prostate cancer and melanoma was heightened due to their extensive and
prolonged exposure.
However, Cancer Research UK, a charity
organization specializing in cancer research and awareness, opined that cancer
can be related to other lifestyle factors, such as pilots sunbathing more
frequently than the average person, due to their work/travel schedules.
Similarly, a group of Italian researchers
studied the health risks of cosmic radiation exposure in female flight crew
members.
The study found that the risk of developing
breast cancer and melanomas was higher in women who were working on planes more
frequently, but the researchers also admitted that they cannot say for sure if
this increased risk was due to cosmic radiation exposure alone.
Safe Limits
There is no standard limit of permissible
cosmic radiation; the standard level varies between countries.
According to the non-profit scientific
professional organization Health Physics Society, which specializes in
radiation safety, a traveler who spends more than 5000 hours in the air each
year is at considerable risk for cosmic radiation exposure.
The Health Physics Society advises that
cosmic radiation exposure should be below 50 millisieverts on an annual basis
and below 100 millisieverts over the course of a lifetime.
Hussain
Kanchwala
is an Electronic Engineer from University of Mumbai. He is a tech aficionado
who loves to explicate on wide range of subjects from applied and
interdisciplinary sciences like Engineering, Technology, FinTech, Pharmacy,
Psychology and Economics.
No comments:
Post a Comment