Answer to Question #11418 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — Airplanes

The following question was answered by an expert in the appropriate field:


I read that the average safe dose for children from radiation during airplane flights is 1 millisievert (mSv). How many hours of flying round-trip from Miami, Florida, to Cairo, Egypt, would equal 1 mSv? I'm concerned because we took our three children, including a one-year-old child, to Egypt round-trip from Miami, and we might have to do it again in a couple of months. Is this safe for our children and toddler? Would these trips increase their cancer risk?


Airline crew and business frequent flyers spend hundreds of hours in the air, and for those people radiation exposures may reach significant levels. For ordinary travelers like you and your children taking a few trips per year, the cosmic radiation exposure in an aircraft should be of no concern.

See general information on the Health Physics Society (HPS) Ask The Experts website.

A quick calculation using the Federal Aviation Administration (FAA) CARI-6 program for Miami (MIA) to Cairo (CAI) performed with reasonable values of flight times and altitudes results in an estimated round-trip dose of about 0.1 mSv for this route. So the recommended dose limit of 1 mSv per year (mSv y-1) would not be reached until 10 of these trips were taken.

And, as can also be found elsewhere on the HPS website (e.g., Question 8900), the value of 1 mSv is an administrative limit used in regulations concerning radiation protection. It is not a value that represents a boundary between "safe" and "unsafe" exposure levels. Demonstrable harm occurs at significantly higher doses. Exposures of the magnitude from these flights are comparable in magnitude to those that occur from variations in background radiation over different parts of the earth; e.g., high-altitude cities like Denver compared with coastal Florida. So there is nothing for you to worry about as a result of this travel.

Robert Barish, PhD, CHP

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
Answer posted on 4 December 2015. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.