“Cosmic radiation exposure on a commercial flight increases as the aircraft flies closer to Earth's magnetic poles.”

“The radiation exposure is maximum at the poles and minimum at the equator because of the effect of Earth’s magnetic field. … That means flight crews and travelers on polar flights from the U.S. to Asia or from the U.S. to Europe are exposed to higher levels of radiation.

The farther north or south you are from the Equator, the more radiation you will receive. This is a result of the Earth's magnetic field deflecting some of the cosmic radiation away from the equator and toward the North and South poles.

Near the magnetic poles, where the geomagnetic field is nearly vertical to the ground, the maximum number of primary cosmic radiation particles can reach the atmosphere and generate secondary radiation that penetrates to aviation altitudes. Thus, rates of exposure to cosmic radiation are higher in polar regions, and lower near the equator

The Earth’s atmosphere and magnetic field shield against CIR, but this protection decreases with higher altitudes and more polar latitudes, thereby significantly impacting circumpolar flights operating at cruising altitudes of 35,000 feet or above (10). … Overall, GCR levels are estimated to double for each 4,500 feet increase in altitude, and radiation levels at polar latitudes are approximately twice as high as at the equator (10).

Less radiation will be received on a lower-latitude flight because of the greater amount of radiation shielding provided by the Earth’s magnetic field. This shielding is greatest near the equator and gradually decreases to zero as one goes north or south. Galactic cosmic radiation levels over the polar regions are about twice those over the geomagnetic equator at the same altitudes.

If one were to fly an aircraft at a constant altitude from the geomagnetic equator towards the north or south magnetic pole, the dose rate would increase with distance from the equator.

The earth's magnetic field (geomagnetic field) provides some shie!ding from incoming cosmic radiation particles. … The shielding is greatest over the geomagnetic equator (near the geographic equator) and decreases to zero as one approaches the north or south polar regions. … Thus, at a given cruise altitude, the galactic radiation dose-rate increases with distance north or south of the equator until it reaches a plateau at high latitudes.

However, near the poles (high latitudes), as the geomagnetic field is nearly vertical to the ground, the primary cosmic ray particles can easily reach the atmosphere. … The radiation doses at polar latitudes can be approximately two times that at the equator at similar altitudes [6] [7] . … The long-haul fl ights close to the polar region (e.g., BKK-HEL and BKK-ARN) correspond to a high exposure to cosmic radiation (Figure 4 ).

Although Earth's magnetic field and atmosphere offer some protection, at high aviation altitudes and particularly near the poles, this shielding effect is weaker leading to increasing radiation exposure and related health risks.

In addition to the atmospheric shielding, the Earth’s magnetic field provides maximum protection from cosmic rays along the magnetic equator with a decreasing effect toward higher latitudes and negligible protection close to the magnetic poles. … Accordingly, the greatest dose rate is reached at high latitudes, where the geomagnetic shielding is minimal, and the cutoff rigidity is zero.

At the geomagnetic equator, where field lines are nearly parallel to the Earth's surface, particles with insufficient rigidity are bent back into interplanetary space before they can enter the atmosphere. Away from the geomagnetic equator, closer to the geomagnetic poles, the field lines are more perpendicular to the Earth's surface, and therefore more parallel to the trajectories of the incoming ions. Thus, many ions that could not enter at the equator can reach the atmosphere.

As a result of the geomagnetic shielding effects discussed above, solar modulation of the atmospheric dosimetric quantities is maximum at the poles and minimum near the equator. … In the polar regions there is virtually no momentum shielding by the geomagnetic field, which maximizes the variation in the atmospheric dosimetric quantities due to the modulation of the heliospheric GCR spectrum by the interplanetary medium.

Regarding the geographic coordinates, it was observed that, globally, the maximum ionization rate was found in polar regions while, at lower latitudes, the ionization rate reached minimum. … Greater values of the dH*(10)/dt were observed in the polar regions (Rc = 0–2 GV) and lower values near the equator (Rc = 15–17 GV), for both solar minima and maxima conditions.

Recall from section 3.2 that the spectral filtering of GCR and SEP ions by the geomagnetic field is a function of the vertical cutoff rigidity. … The effect of geomagnetic storm activity is to suppress the cutoff rigidity (Kress et al., 2010; Mertens et al., 2010), which in turn increases the GCR and SEP dosimetric and flux and fluence quantities. The cutoff rigidity suppression is greatest at high latitudes.

Higher altitude (>8 km) and higher latitude air traffic routes above 8 km (Friedberg and Copeland, 2003, 2011; Tobiska et al., 2016) are particularly vulnerable because the Earth’s magnetic field offers less shielding in these regions.

The polar region shows significantly higher radiation exposure across all metrics compared to mid-latitudes. … This reflects the lower geomagnetic cutoff rigidity at higher latitudes, allowing more solar protons to penetrate.

As a result of the geomagnetic shielding effects discussed above, solar modulation of the atmospheric dosimetric quantities is maximum at the poles and minimum near the equator. … In the polar regions there is virtually no momentum shielding by the geomagnetic field, which maximizes the variation in the atmospheric dosimetric quantities due to the modulation of the heliospheric GCR spectrum by the interplanetary medium.

One approach is flying at lower magnetic latitudes to gain more Earth magnetic field shielding, and the other is flying lower altitudes to use atmosphere depth shielding.

The highest radiation doses are received by long-haul crews flying the polar routes. These can be up to 6 mSv in a year.

For high cutoff rigidity environments (8– 12 GV), the median dose rate is generally between 1.2–1.7 μGy/h, well over 1 μGy/h lower than flights in the 0– 4 GV range (Table 4).

the flights on high-latitude or intercontinental routes are at risk of exceeding the maximum public and prenatal exposure during a single SEP event or through several (∼5–10) round-trip, high-latitude flights from GCR exposure … the median absorbed dose rate in silicon and tissue were 2.8 and 4.2 μGy/h, respectively, the median dose equivalent rate was 8.6μSv/h, the median ambient dose equivalent rate was 13.3μSv/h, and the median effective dose rate was 17.8μSv/h … For high cutoff rigidity environments (8–12GV), the median dose rate is generally between 1.2–1.7μGy/h, well over 1μGy/h lower than flights in the 0–4GV range

As it is expected, the polar route shows the highest radiation exposure of 0.0793 mSv per flight on average. It is notable that non-polar route shows comparable but slightly lower radiation dose of 0.0695 mSv.

The highest radiation doses are received by long haul crews flying the polar routes. These can be up to 6 mSv in a year.

Only the highest-energy particles (usually protons or heavy ions) are found in equatorial and low latitudes while even low-energy particles (including many electrons) enter the atmosphere at high latitudes. … Because there are additional lower-energy particles (greater flux), the result is a higher radiation environment at higher magnetic latitudes.

Counterintuitively the flights with major duration are not the more irradiated ones. Instead, long geodetic transpolar flights are more irradiated than long geodetic flights that does not fly over the poles.

Earth’s magnetic shield protects us from the cosmic radiation and is strongest at the equator and weakest near the poles. … When we fly in an airplane, we are closer to outer space. With less atmosphere to protect us, we are exposed to more cosmic radiation than when we are standing on the ground.

Generally speaking, Earth’s magnetic field is weaker at the magnetic poles, and therefore the cosmic radiation levels are higher in the Polar Regions and decline towards the Equator.

The intensity of cosmic radiation is also influenced by the earth’s magnetic field, which can deflect cosmic radiation. Deflection is greatest at the equator and least at the poles where cosmic radiation can penetrate deeper into the atmosphere. … Because cosmic radiation increases with altitude and latitude, air travel results in an additional radiation dose compared with staying on the ground. Higher doses are associated with long-haul and trans-polar flights, e.g.to North America and the far-east.

• Latitude: the closer we get to the poles, the greater the dose … • The farther north or south one is from the Equator, the more radiation one will receive. • (this is as a result of magnetic field deflecting some of the cosmic radiation away from the equator and toward the North and South poles).

The NAIRAS model predicts biologically hazardous radiation exposure to crew and passengers onboard aircraft or spacecraft from the ever-present galactic cosmic rays (GCR), inner radiation belt trapped protons (TRP) in low-Earth orbit (LEO), and the episodic, transient solar energetic particles (SEP) originating from solar eruptive events.

Magnetic reconnection occurs when magnetic fields and particles from the Sun interact with Earth’s magnetic field. This process results in the funneling of charged particles down toward Earth and our technology along our planet’s magnetic field lines, shown in yellow.

Because of the orientation of the geomagnetic field, which is predominately dipolar in nature, the polar regions and high latitudes are susceptible to penetrating GCR (and SEP) particles. … The latitudinal variation in the dose equivalent rates is determined by the low-momentum shielding provided by the Earth’s magnetic field (Mertens et al., 2010a; 2009; 2008; 2007a; Wilson et al., 2003; 1991). … However, the polar region receives the largest quantity of radiation because the shielding provided by Earth’s magnetic field rapidly approaches zero near the magnetic pole.

Mertens, C. J., B. T. Kress, M. Wiltberger, S. R. Blattnig, T. S. Slaba, S. C. Solomon, and M. Engel (2010),Geomagnetic influence on aircraft radiation exposure during a solar energetic particle event in October 2003, Space Weather, 8, S03006, doi:10.1029/2009SW000487.

Only the highest-energy particles (usually protons or heavy ions) are found in equatorial and low latitudes while even low-energy particles (including many electrons) enter the atmosphere at high latitudes. … Because there are additional lower-energy particles (greater flux), the result is a higher radiation environment at higher magnetic latitudes.

Because of the orientation of the geomagnetic field, which is predominately dipolar in nature, the polar regions and high latitudes are susceptible to penetrating GCR (and SEP) particles. … At each geographic location, the minimum momentum per unit charge (magnetic rigidity) a vertically incident particle can have and still reach a given location above the earth is called the geomagnetic vertical cutoff rigidity.

Galactic cosmic radiation exposure and associated health risks for air carrier crewmembers.

As the remaining higher-energy cosmic rays penetrate deeper into the solar system, individual planetary magnetic fields deflect still more of them. Eventually, the most energetic cosmic rays make it all the way into the Earth’s atmosphere where they collide with nitrogen and oxygen atoms to produce secondary ‘showers’ of energetic particles.