Influence of Space Weather on Aircraft Ionizing Radiation Exposure

There is a growing concern for the health and safety of commercial aircrew and passengers due to their exposure to ionizing radiation with high linear energy transfer (LET), particularly at high latitudes. The International Commission of Radiobiological Protection (ICRP), the EPA, and the FAA consider the crews of commercial aircraft as radiation workers. During solar energetic particle (SEP) events, radiation exposure can exceed annual limits, and the number of serious health effects, especially to the unborn child of a pregnant air traveler, is expected to be quite high if precautions are not taken. There is a need for a capability to monitor the real-time radiation levels at commercial airline altitudes in order to: (1) provide a continuous assessment of the ionizing radiation field for tracking individual aircrew exposures levels, for the airlines and the FAA to develop policy and procedure for recommending aircrew radiation exposure limits and exposure mitigation; (2) provide time-critical data during SEP events for airline management and pilots to make decisions that balance the cost to flight path alterations against radiation exposure and health risks to passenger and crew; and (3) provide the airline industry with an archived database of radiation exposure levels for assessing the impact of ionizing radiation on the global air transportation system, especially in view of the current and future exponential increase in the number of polar routes. Currently under development is the Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) model, which provides a global, data-driven, real-time, radiation dose prediction for archiving and assessing the biologically harmful radiation exposure levels at commercial airline altitudes. The NAIRAS model brings to bear the best available suite of Sun-Earth observations and models for simulating the atmospheric ionizing radiation environment. Observations are utilized from ground (neutron