MDPilot
Well-Known Member
I found an interesting article on radiation from an airline website. It focuses on flight attendants, but of course pilots are exposed to the same radiation hazards. Just thought it would be an interesting topic.
Cosmic Radiation
Cosmic radiation comes from outside the atmosphere. It represents the combination of two energy sources:
Galactic radiation contains particles of energy that come from outside the solar system, (often the product of exploding stars), as well as sub-atomic particles produced when these particles collide with elements (nitrogen, oxygen, etc.) in the higher atmosphere.
Solar radiation is the particulate energy produced continuously from the sun. The purpose of this article is to explain cosmic and other naturally occurring forms of radiation, and to discuss the possible health risks associated with exposure to cosmic radiation. We want to provide information to flight crew members to raise awareness so they can make informed and educated decisions regarding their work environment. The following Q & A has been provided to help address some of those concerns:
Q. What can you tell me about solar flares?
A. The occurrence of a solar flare is unpredictable and the frequency follows an 11 year pattern known as the solar cycle. The years 2000 and 2001 will be a high point on the solar cycle, with an increase in anticipated solar flares. An interesting trend has been observed between galactic and solar radiation. The amount of galactic radiation entering the atmosphere varies inversely with the solar cycle so when solar activity is high the atmosphere is more effective in deflecting galactic radiation. Conversely, when the solar cycle is at a low point, galactic radiation can better penetrate the atmosphere. This give and take between the two sources has resulted in a total combined level of cosmic radiation remaining constant since scientists began monitoring some 40 years ago.
Q. Are F/As exposed to this radiation?
A. Yes, to a slight degree depending on latitude, altitude, and duration of flight.
At specific latitudes, cosmic radiation increases.
Cosmic radiation levels over the magnetic poles are double the levels over the equator. With these variables, the amount of time spent at different altitudes and latitudes can influence the dose of cosmic radiation. Solar flares rarely contribute to any significant changes in cosmic radiation levels while in flight.
Q. Can this exposure be measured?
A. The standard unit of measurement is known as the Sievert (Sv). Cosmic radiation is measured in milliSieverts (mSv). (1.0 Sv = 1000 mSv).
Examples of Cosmic Radiation Exposure
With the variables that affect cosmic radiation we can calculate an average cosmic radiation dose using data provided from the Civil Aeromedical Institute (CAMI) at the Federal Aviation Administration (FAA).
The table below provides an estimate of cosmic radiation doses to flight crews from 11 nonstop flights, using a variety of latitudes and cruise altitudes.
Cosmic Radiation Dosages for Selected Commercial Flights
Origin - Destination
Highest Altitude (000 ft)
Mean Altitude (000 ft)+
Air Time (hours)
Block Hours++
mSv (milli-seivert)
mSv / 100 block hrs
Seattle WA-Portland OR 21
12
0.4
0.6
0.0001
0.02
Los Angeles CA-Honolulu HI 35
33
5.2
5.6
0.012
0.21
Honolulu HI-Los Angeles CA 40
34
5.1
5.6
0.014
0.25
Los Angeles CA-Tokyo JA 40
34
11.7
12.0
0.035
0.29
Tokyo JA-Los Angeles CA 37
34
8.8
9.2
0.028
0.30
Seattle WA-Anchorage AK 35
32
3.4
3.7
0.014
0.38
London UK-New York NY 37
34
6.8
7.3
0.032
0.44
New York NY-Seattle WA 39
34
4.9
5.3
0.024
0.46
Tokyo JA-New York NY 41
35
12.2
12.6
0.06
0.47
New York NY-Tokyo JA 43
36
13.0
13.4
0.064
0.48
Athens GR-New York NY 41
39
9.4
9.7
0.056
0.58
Q. How much exposure is too much?
A. Flight crews have a recommended limit of 20 mSv/year, averaged over five years, with no dose exceeding 50 mSv in a single year.
For a pregnant crew member , the recommended limit is 2.0 mSv (excluding medical exposures) for the duration of the pregnancy. The risk of developing cancer is the primary health concern of exposure to cosmic radiation. The average person has a 23% risk of contracting cancer in their lifetime. Studies show there is no significant increase in cancer rates for flight crew members compared to the general population and there is no proven link between cosmic radiation and an increase in cancer rates.
Q. Should pregnant flight attendants or flight attendants considering pregnancy be concerned about cosmic radiation?
The recommended radiation exposure limit for pregnant women is less than that of other employees due to concerns about potentially higher rates of miscarriages and birth defects. The recommended limit is 2.0 mSv (excluding medical exposures) for the duration of the pregnancy.
We recommend pregnant flight attendants and flight attendants considering pregnancy discuss this concern with their Doctor.
Q. How can I manage my exposure to cosmic radiation
A. Flight attendants wishing to limit their exposure to cosmic radiation, especially those considering or currently pregnant, can do so by selecting shorter flight segments at lower altitudes and latitudes.
Q. How can I measure my exposure to cosmic radiation?
A. There are several computer programs that provide estimates of cosmic radiation exposure. These estimates are based on data collected from the National Aeronautic Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA). The most widely accepted is the CARI-6 program from the FAA Civil Aeromedical Institute (CAMI) in Oklahoma City. You can download this software at http://www.cami.jccbi.gov/AAM-600/610/600Radio.html. This software can calculate the radiation dose for a specific flight. It also provides up-to-date information on potential changes in the solar cycle. However, these dosimeters are not an effective method for measuring cosmic radiation, as they can not separate cosmic radiation from other types of radiation in the atmosphere.
Q. Is there somewhere I can get additional information?
A. The XXXXXX website has additional information, including a recent article published by the Air Transport Association on November 21, 2000, titled, DOT/FAA Aviation Medicine Report: Galactic Cosmic Radiation Exposure of Pregnant Aircrew members 11.
Summary
The effect of cosmic radiation exposure to flight attendants and their offspring over a long term period is still unknown. Most current research is based on the nuclear disasters at Hiroshima and Nagasaki with minimal research available from the Three Mile Island and Chernobyl events.
However, this research does not show conclusive evidence of the harmful effects of exposure to cosmic radiation
Natural background exposure to ionizing radiation, such as radon and medical radiation, has been a part of our environment since conception. This non-occupational source may equal, perhaps exceed, the occupational dose of cosmic radiation to flight crew members.
Significantly, exposure to naturally occurring forms of ionizing radiation is minimal compared to other known risk factors in our environment such as smoking, obesity, unhealthy diet, excessive alcohol intake, etc. An understanding of cosmic radiation is important but attention to lifestyle factors that contribute to heart disease, cancer and stroke, have a greater impact on your health.
Cosmic Radiation
Cosmic radiation comes from outside the atmosphere. It represents the combination of two energy sources:
Galactic radiation contains particles of energy that come from outside the solar system, (often the product of exploding stars), as well as sub-atomic particles produced when these particles collide with elements (nitrogen, oxygen, etc.) in the higher atmosphere.
Solar radiation is the particulate energy produced continuously from the sun. The purpose of this article is to explain cosmic and other naturally occurring forms of radiation, and to discuss the possible health risks associated with exposure to cosmic radiation. We want to provide information to flight crew members to raise awareness so they can make informed and educated decisions regarding their work environment. The following Q & A has been provided to help address some of those concerns:
Q. What can you tell me about solar flares?
A. The occurrence of a solar flare is unpredictable and the frequency follows an 11 year pattern known as the solar cycle. The years 2000 and 2001 will be a high point on the solar cycle, with an increase in anticipated solar flares. An interesting trend has been observed between galactic and solar radiation. The amount of galactic radiation entering the atmosphere varies inversely with the solar cycle so when solar activity is high the atmosphere is more effective in deflecting galactic radiation. Conversely, when the solar cycle is at a low point, galactic radiation can better penetrate the atmosphere. This give and take between the two sources has resulted in a total combined level of cosmic radiation remaining constant since scientists began monitoring some 40 years ago.
Q. Are F/As exposed to this radiation?
A. Yes, to a slight degree depending on latitude, altitude, and duration of flight.
At specific latitudes, cosmic radiation increases.
Cosmic radiation levels over the magnetic poles are double the levels over the equator. With these variables, the amount of time spent at different altitudes and latitudes can influence the dose of cosmic radiation. Solar flares rarely contribute to any significant changes in cosmic radiation levels while in flight.
Q. Can this exposure be measured?
A. The standard unit of measurement is known as the Sievert (Sv). Cosmic radiation is measured in milliSieverts (mSv). (1.0 Sv = 1000 mSv).
Examples of Cosmic Radiation Exposure
With the variables that affect cosmic radiation we can calculate an average cosmic radiation dose using data provided from the Civil Aeromedical Institute (CAMI) at the Federal Aviation Administration (FAA).
The table below provides an estimate of cosmic radiation doses to flight crews from 11 nonstop flights, using a variety of latitudes and cruise altitudes.
Cosmic Radiation Dosages for Selected Commercial Flights
Origin - Destination
Highest Altitude (000 ft)
Mean Altitude (000 ft)+
Air Time (hours)
Block Hours++
mSv (milli-seivert)
mSv / 100 block hrs
Seattle WA-Portland OR 21
12
0.4
0.6
0.0001
0.02
Los Angeles CA-Honolulu HI 35
33
5.2
5.6
0.012
0.21
Honolulu HI-Los Angeles CA 40
34
5.1
5.6
0.014
0.25
Los Angeles CA-Tokyo JA 40
34
11.7
12.0
0.035
0.29
Tokyo JA-Los Angeles CA 37
34
8.8
9.2
0.028
0.30
Seattle WA-Anchorage AK 35
32
3.4
3.7
0.014
0.38
London UK-New York NY 37
34
6.8
7.3
0.032
0.44
New York NY-Seattle WA 39
34
4.9
5.3
0.024
0.46
Tokyo JA-New York NY 41
35
12.2
12.6
0.06
0.47
New York NY-Tokyo JA 43
36
13.0
13.4
0.064
0.48
Athens GR-New York NY 41
39
9.4
9.7
0.056
0.58
Q. How much exposure is too much?
A. Flight crews have a recommended limit of 20 mSv/year, averaged over five years, with no dose exceeding 50 mSv in a single year.
For a pregnant crew member , the recommended limit is 2.0 mSv (excluding medical exposures) for the duration of the pregnancy. The risk of developing cancer is the primary health concern of exposure to cosmic radiation. The average person has a 23% risk of contracting cancer in their lifetime. Studies show there is no significant increase in cancer rates for flight crew members compared to the general population and there is no proven link between cosmic radiation and an increase in cancer rates.
Q. Should pregnant flight attendants or flight attendants considering pregnancy be concerned about cosmic radiation?
The recommended radiation exposure limit for pregnant women is less than that of other employees due to concerns about potentially higher rates of miscarriages and birth defects. The recommended limit is 2.0 mSv (excluding medical exposures) for the duration of the pregnancy.
We recommend pregnant flight attendants and flight attendants considering pregnancy discuss this concern with their Doctor.
Q. How can I manage my exposure to cosmic radiation
A. Flight attendants wishing to limit their exposure to cosmic radiation, especially those considering or currently pregnant, can do so by selecting shorter flight segments at lower altitudes and latitudes.
Q. How can I measure my exposure to cosmic radiation?
A. There are several computer programs that provide estimates of cosmic radiation exposure. These estimates are based on data collected from the National Aeronautic Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA). The most widely accepted is the CARI-6 program from the FAA Civil Aeromedical Institute (CAMI) in Oklahoma City. You can download this software at http://www.cami.jccbi.gov/AAM-600/610/600Radio.html. This software can calculate the radiation dose for a specific flight. It also provides up-to-date information on potential changes in the solar cycle. However, these dosimeters are not an effective method for measuring cosmic radiation, as they can not separate cosmic radiation from other types of radiation in the atmosphere.
Q. Is there somewhere I can get additional information?
A. The XXXXXX website has additional information, including a recent article published by the Air Transport Association on November 21, 2000, titled, DOT/FAA Aviation Medicine Report: Galactic Cosmic Radiation Exposure of Pregnant Aircrew members 11.
Summary
The effect of cosmic radiation exposure to flight attendants and their offspring over a long term period is still unknown. Most current research is based on the nuclear disasters at Hiroshima and Nagasaki with minimal research available from the Three Mile Island and Chernobyl events.
However, this research does not show conclusive evidence of the harmful effects of exposure to cosmic radiation
Natural background exposure to ionizing radiation, such as radon and medical radiation, has been a part of our environment since conception. This non-occupational source may equal, perhaps exceed, the occupational dose of cosmic radiation to flight crew members.
Significantly, exposure to naturally occurring forms of ionizing radiation is minimal compared to other known risk factors in our environment such as smoking, obesity, unhealthy diet, excessive alcohol intake, etc. An understanding of cosmic radiation is important but attention to lifestyle factors that contribute to heart disease, cancer and stroke, have a greater impact on your health.
