The concentration of ozone (triatomic oxygen, O3) and the intensity of cosmic radiation both increase with altitude. Ozone is easily converted to oxygen by heat and various catalytic processes. In modern jet aircraft, almost all ozone in the ambient air is converted to oxygen in the compressors that provide pressurized air for the cabin.
During descent, when engine power is low, a build-up of ozone is prevented by catalytic converters. At usual cruising altitudes, the concentration of ozone in the cabin air is negligible. Cosmic radiation is the sum of solar and galactic radiation