Israeli Scientists Link Airplane Radiation Exposure to Solar Activity
Israeli researchers have determined that the level of cosmic radiation experienced by airline passengers is significantly influenced by solar activity. Their study, published in the Journal of Geophysical Research: Atmospheres, found that lower solar activity leads to a higher influx of high-energy particles reaching Earth's atmosphere.
The research team, including Roy Yaniv from the Hebrew University of Jerusalem and Sheba Medical Center, Professor Yoav Yair from Reichman University, and Professor Colin Price from Tel Aviv University, analyzed data from six high-altitude balloon launches conducted between October 2014 and August 2016 from the Weizmann Observatory near Mitzpe Ramon. Sensors on these balloons measured ionization and radiation levels up to approximately 35 kilometers.
Radiation intensity increased with altitude, peaking around 17-20 kilometers before beginning to decrease. At approximately 10 kilometers, a typical altitude for commercial flights, the measured dose rate equivalent was around 0.9-1.3 microsieverts per hour. The study revealed a clear inverse relationship with solar activity: during periods of high solar activity, the sun more effectively shields the solar system from galactic cosmic rays, resulting in fewer such particles reaching Earth. Conversely, during solar minimums, more particles arrive.
The scientists calculated that during minimal solar activity, the measured radiation levels at flight altitudes could be approximately 40-60% higher than during peak solar activity. They caution that this figure is an extrapolation and not based on direct comparative measurements during a full solar minimum and maximum. Additionally, the sensors primarily assessed the electromagnetic component of the radiation field, while the total dose at flight altitude also includes neutrons, which contribute significantly to exposure in models.
These findings could enable more accurate assessments of radiation exposure for both flight crews and passengers, taking into account not only the flight route and altitude but also the current phase of the solar cycle.
