How does cosmic radiation exposure change with altitude?

• A. Exposure is unaffected by altitude
• B. Higher altitude increases exposure; cumulative exposure is considered for long-term health risk; track and mitigate where possible
• C. Exposure decreases with altitude
• D. Only flight duration matters for exposure

Answer: (B)

Cosmic radiation exposure increases with altitude because the atmosphere and Earth's magnetic field provide shielding that weakens as you rise. At higher cruising altitudes, less shielding means more high-energy particles reach the body per hour, so the dose rate goes up. Since exposure accumulates over time, the long-term health risk depends on the total cumulative dose from all flights, not just a single flight. That’s why flight planning and monitoring focus on tracking and mitigating exposure when possible—by choosing routes, managing altitudes, and using dosimeters to keep the overall dose within safe limits.