Cosmic Radiation Exposure: A Monte Carlo Study of Altitude and Latitude Effects and Implications for Aviation Safety

Exposure to ionizing radiation originates primarily from terrestrial and cosmic radiation sources. Cosmic-radiation exposure depends strongly on altitude and is additionally influenced by latitude and solar activity. Particular attention should be paid to aircraft passengers and aircrew, who may receive elevated radiation doses due to prolonged exposure at flight altitudes. In this study, Monte Carlo simulations were performed using the Geant4 toolkit (version 11.3) to investigate secondary cosmic-ray particles, including muons, neutrons, protons, electrons/positrons, and gamma photons, at altitudes of 0 m, 2100 m, and 11,300 m and latitudes of 0°, 30°, 45°, 60°, and 90°. Deposited energies in a water phantom representing the human body were used to calculate equivalent dose rates and estimate annual effective doses. The average equivalent dose rates were 0.036, 0.22, and 6.9 μSv·h−1 at 0 m, 2100 m, and 11,300 m, respectively. Dose rates showed a pronounced latitude dependence, increasing from low latitudes and reaching maximum values at 60°, followed by a decrease at 90°, consistent with the reported latitude effect of cosmic radiation. The annual effective dose for the general population at sea level ranged from 0.28 to 0.35 mSv, with an average of 0.31 mSv. For annual flight times of 10, 50, and 100 h, passenger doses were 0.069, 0.34, and 0.69 mSv, respectively, remaining below 1 mSv. For aircrew, annual doses were 3.44, 4.82, and 6.19 mSv for 500, 700, and 900 flight hours, respectively, remaining below 20 mSv. The results are consistent with literature data and demonstrate the applicability of Monte Carlo simulations for cosmic-radiation exposure assessment.