[ RadSafe ] Dose from Airtravel

Tue May 23 08:19:15 CDT 2017

Some sources of information from the HPS “Ask the Expert”

What radiation doses do people receive from flying commercially?

Feng YJ, Chen WR, Sun TP, Duan SY, Jia BS, Zhang HL. Estimated cosmic radiation doses for flight personnel. Space Med Med Eng 15(4):265–269; 2002.

The average effective dose rate of all flights of Xinjiang Airlines from 1997 to 1999 was 2.38 µSv h-1.

The average annual cosmic radiation dose for flight personnel was 2.19 mSv.

Annual individual doses of all monitored flight personnel are well below the limit of 20 mSv y-1 recommended by the International Commission on Radiological Protection (ICRP).

Bottollier-Depois JF, Chau Q, Bouisset P, Kerlau G, Plawinski L, Lebaron-Jacobs L. Assessing exposure to cosmic radiation during long-haul flights. Radiat Res 153(5 Pt. 1):526–532; 2000.

The lowest dose rate measured was 3 µSv h-1 during a Paris-Buenos Aires flight.

The highest rates were 6.6 µSv h-1 during a Paris to Tokyo flight and 9.7 µSv h-1 on the Concorde in 1996–1997.

The corresponding annual effective dose, based on 700 hours of flight for subsonic aircraft and 300 hours for the Concorde, can be estimated at between 2 mSv for the least exposed routes and 5 mSv for the more exposed routes.

Waters M, Bloom TF, Grajewski B. The National Institute for Occupational Safety and Health/Federal Aviation Administration (NIOSH/FAA) working women's health study: Evaluation of the cosmic-radiation exposures of flight attendants. Health Phys 79(5):553–559; 2000.

Radiation dose levels represent a complex function of duration of flight, latitude, and altitude.

Based on data collected for this study, radiation dose levels that would be experienced by a flight crew are well below current occupational limits recommended by the ICRP and the FAA of 20 mSv y-1.

The National Council on Radiation Protection and Measurements (NCRP) recommends a monthly equivalent dose limit of 0.5 mSv. The ICRP recommends the radiation limit during pregnancy be 1 mSv.

Only flight crews flying both a large number of hours during pregnancy (for example, 100 hours in a month) and strictly the highest dose-rate routes (typically global routes such as —United States to Buenos Aires or United States to Tokyo) would exceed the NCRP monthly guideline.

Friedberg W, Copeland K, Duke FE, O'Brien K 3rd, Darden EB Jr. Radiation exposure during air travel: Guidance provided by the FAA for air carrier crews. Health Phys 79(5):591–595; 2000.

•       Seattle to Portland: 0.03 mSv per 100 block hours

•       New York to Chicago: 0.39 mSv per 100 block hours

•       Los Angeles to Honolulu: 0.26 mSv per 100 block hours

•       London to New York: 0.51 mSv per 100 block hours

•       Athens to New York: 0.63 mSv per 100 block hours

•       Tokyo to New York: 0.55 mSv per 100 block hours

Oksanen PJ. Estimated individual annual cosmic radiation doses for flight crews. Aviat Space Environ Med 69(7):621–625; 1998.

•       In this study, crew members averaged 673 block hours and pilots 568 block hours.

•       Average annual cosmic ray dose for cabin crews was 2.27 mSv.

•       Average annual cosmic ray dose for long-distance flight captains was 2.19 mSv

I understand that the radiation dose while flying diminishes as you get closer to the equator. Is this true?

Because incoming cosmic radiation particles are deflected by the Earth's magnetic field, the intensity of in-flight radiation is a function of both altitude and latitude. In general, radiation shielding by the geomagnetic field is greatest at the equator and decreases as one goes north or south. At typical flight altitudes of 9,000 to 12,000 meters, the difference between the cosmic ray dose rates at the equator and at high latitudes is about a factor of two to three, depending on where one is in the approximately 11-year solar cycle. So if all your flying is in the equatorial zone, you would expect that the dose rates at altitude are two to three times lower than for your colleagues flying more northern or southern routes. Of course, your total exposure will be a function of the hours you spend at altitude. In any case, your annual radiation burden will be well within the limits considered acceptable for occupational exposure by such organizations as the ICRP.

Have there been studies of long-term, low-level exposure to radiation during commercial flights and the effects for flight crews?

At present, the Airline Pilots Association is conducting dosimetry studies for its membership and NIOSH is engaged in a study of reproductive disorders among flight attendants. Several studies have already been published; some show an increase in various malignancies among crew members while others show no increased risk. The following references all present data showing an increase in malignancies among flight crew members with the exception of the second British Airways paper which, as discussed above, reevaluates data published in the earlier reference. These papers can be obtained through your local library. 

For pilots flying below 1,800 meters for 200 hours a year is there any danger from cosmic radiation?

Even at ground level, cosmic radiation is part of our normal environment. The Earth's atmosphere absorbs this radiation, so its intensity is least at ground level. The altitude of interest in this question— (1,800 meters) is, of course, ground level in many places. Using the CARI-6 program available from the FAA, the calculated cosmic-ray dose rate at this altitude at high geographic latitude is about 0.0001 mSv h-1. It would, therefore, require 10,000 hours of flying at this altitude to reach the 1 mSv annual limit recommended as a maximum for members of the public exposed to ionizing radiation. It should also be noted that exposures well above this 1 mSv limit are not "dangerous.”

Is there any specific limit for air travel for children?

An annual radiation dose limit of 1 mSv for members of the public has been recommended by both the NCRP here in the United States and by its overseas counterpart, the ICRP. In June 2003 the Health Physics Society, the organization of radiation protection professionals that sponsors this website, reaffirmed that these limits are appropriate. This recommended limit, unchanged for more than 10 years, has generally been adopted into law or regulation by the government agencies that mandate radiation protection programs. No distinction is made between the exposure of adults or minors. However, radiation exposure to the flying public (versus someone who works as a crew member) is not regulated; it is considered a "voluntary" activity. So at least as far as any legal limits are concerned, there are none for this category of exposure, for adult flyers or anyone else.

Regards,

Sandy

Retired, Consultant

From: <radsafe-bounces at health.phys.iit.edu> on behalf of "Krzesniak, Michael F CIV NSWC Crane, Crane Bldg 3059 Code 6054" <michael.krzesniak at navy.mil>
Reply-To: "The International Radiation Protection (Health Physics) Mailing List" <radsafe at health.phys.iit.edu>
Date: Tuesday, May 23, 2017 at 4:31 AM
To: "radsafe at health.phys.iit.edu" <radsafe at health.phys.iit.edu>
Subject: [ RadSafe ] Dose from Airtravel

Having trouble searching the Radsafe digest and didn't find a good source in on-line search.

Looking for dose estimates for checked and carry-on baggage for commercial air travel.  Also, dose estimates for passengers.

Thank you,

Michael Krzesniak

Michael.Krzesniak at navy.mil

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