Cosmic Radiation Risk in Everyday Flights

When travelling by a flight, we usually focus only on reaching the destination. Either we see the scene from the window or think about our food menu. But we rarely think about the invisible power of cosmic ionizing radiation that is travelling with us. For infrequent travellers, it's not harmful, but for pilots, flight attendants and regular passengers, it can be more risky.

In this blog, you'll learn about how cosmic radiation works, who gets affected by it and what precautions one can take.

Everything About Cosmic Radiation: 

Cosmic radiation originates in outer space, likely from distant stars, galaxies and the sun. When these high-energy particles get into the Earth's atmosphere, they create new particles that reach the altitude of flight and can easily enter the human body.

This radiation comes from two main sources during flights:

1. Galactic Cosmic Rays (GCRS)- Galactic Cosmic Rays (GCRs) are high-energy, fully ionized nuclei from galactic space, largely from dying stars, continuously hitting Earth and affected by solar and magnetic activity.
2. Solar Particle Events (SPEs)- Solar Particle Events (SPEs) are sudden releases of powerful charged solar particles, sped into space, which travel along magnetic fields and can reach Earth's polar atmosphere during interactions. 

What Happens When You Fly Higher and Longer

At ground level, the Earth's atmosphere and magnetic field protect us from radiation during air travel. We fly 30,000-40,000 feet up, so the atmosphere shield becomes thinner. As a result, passengers and crew members are easily affected by radiation.

The reason for the increased risk:

• Longtime air travel
• Journey over the polar regions
• Flight during solar flares

Annual Exposure and Comparison:

How much radiation do we receive during a flight? Here is a comparative view:

• At sea level: 0.3 mSv (cosmic only)
• 1-2 international flights per year: 0.5 mSv
• Pilots/ Flight attendants: 2-5 mSv
• A flight during a Solar Eclipse: 0.1-1.0 + mSv per event
• WHO recommended limits during pregnancy: ≤1.0 mSv Total

For comparison, a chest x-ray gives about 0.1 mSv while a CT scan may give up to 10 mSv. While a single flight is no cause of risk but this can be a big concern for those who are in the skies by profession.

Health Implications of Cosmic Radiation:

Cosmic radiation is unseen, but it can cause long-term damage to the human body. The WHO (World Health organization) and IARC ( International Cancer Research Centre) classify ionizing radiation as a Group-1 Carcinogen. Which means it's scientifically proven that these radiations causes cancer in the human body.

This places cosmic radiation in the same risk category as harmful substances like tobacco products, asbestos, and arsenic, all of which are known to cause cellular damage and increase the risk of cancer.

Let's delve into the key health risks associated with prolonged or repeated exposure to cosmic ionizing radiation-

1.Risk of Cancer:

Ionizing radiation releases high-energy electrons, which can damage DNA. If the human body fails to repair this damage, then mutations in cells can occur and cause cancer.

Key Cancers Linked to Cosmic Radiation:

• Breast Cancer: In women flight crew members, it is often seen. Because they are exposed to radiation for a long time, and hormonal sensitivity also plays a role there.
• Leukaemia: A type of blood cancer linked to radiation, which impacts bone marrow and affects blood-forming cells.
• Skin Cancer: At higher altitudes,  the joint impact of UV and ionizing radiation increases the risk of Skin Cancer.

2.Reproductive Health Issues:

Long-term radiation not only causes cancer but also threatens the reproductive health of women and especially in the beginning period of pregnancy.

The first 3 months are most sensitive:

A study by NIOSH has shown that in the first three months of pregnancy, even 0.36 mSv radiation exposure increases the risk of miscarriage. During embryonic cell division and organ formation, radiation is very harmful.

Effect of Solar Particle Events:

From a combined research of NASA and NIOSH, it's been seen that if a pregnant crew member is on a flight during a Solar Particle Event could exceed the radiation limits recommended for pregnancy on that flight alone. This is dangerous because-

• This type of solar event can occur without warning.
• The fetus's nerves and cells are then in a very sensitive state.
• Due to this incident, the risk of birth defects, premature birth or low birth weight can even occur.

That's why pregnant flight attendants or those who travel frequently by air should monitor the space radiation levels, and even if needed, consider rescheduling flights or trip trading to avoid harmful exposure during pregnancy.

3.Potential Cardiovascular Effects:

In recent research, it's been found that low-level long-term radiation can not only cause cancer but can also cause cardiovascular disease and affect blood vessels. It was once thought that the heart and blood vessels might not be very sensitive to this type of radiation. But now researchers are saying:

• Radiation can cause inflammation in blood vessels.
• Plaque can build up in the arteries, which is a risk factor for heart attacks.
• Endothelial dysfunction damages the normalisation of blood flow.

Though this part is still under research, these possibilities have been shown in studies conducted on pilots and astronauts.

Final thoughts:

Cosmic Radiation is not some kind of imagination; it's a scientifically proven reality, and for those who travel frequently by air, it's a sensitive health issue.

For those who travel occasionally, it's not that risky, but for pilots, cabin crew, and pregnant individuals, it's crucial to monitor, calculate, and manage exposure levels wherever possible. With the right knowledge, we can stay alert, make safer choices, advocate for better workplace protections and plan more responsibly for health.