Answer to Question #12510 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — Airplanes

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

Q

My niece just turned three years old and has been on 90 flights, almost half of which have been international flights. Because of her age and number of flights, does the radiation dose she has received from flying pose a health threat?

A

I can understand your concern since you are worried that, as a young girl, your niece may be more susceptible to harm from radiation than an adult would be. For radiation exposures at these levels, there is no evidence that this is the case.

Over a three-year period, your niece has taken 90 flights, including both domestic and international travel. Without specific itinerary information, it is not possible to accurately derive a cumulative radiation dose for that travel, but as a reasonable alternative, I have used radiation averages for typical domestic and international routes calculated using the US Federal Aviation Administration (FAA) Cari-6 computer program. Assuming a relatively uniform spacing of the travel over that three-year period, I derived an annual radiation dose of about 0.7 millisievert (mSv).

As can be found elsewhere on the Health Physics Society website (e.g., Question 8900), the value of 1 mSv per year is used as an administrative limit in federal and state regulations concerning radiation protection. It is not a value that represents a boundary between "safe" and "unsafe" exposure levels. Rather, demonstrable harm occurs at significantly higher doses. The Health Physics Society "advises against estimating health risks to people from exposures to ionizing radiation that are near or less than natural background levels . . . A person might accumulate an equivalent dose from natural background radiation of about 50 mSv in the first 17 years of life . . ." So the exposure calculated here for your niece is more than 50 times lower than can be associated with known radiation health risks.

The radiation exposure she may have received from these flights is within the recommended dose limits for members of the public, regardless of their age. Exposures of this magnitude are comparable 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, on her behalf, you have nothing to worry about as a result of this travel. Going forward, you may wish to use the Cari-6 program to compile specific dose information for her travel. See also the general information on radiation risks from flying on the Health Physics Society's Ask the Experts website.

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 June 2018. 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.