May 27, 2009
Personally, I’ve never had a problem with a fear of flying, a lot of people suffer from this often debilitating phobia though despite reassurances about road death statistics being much worse than air crashes. That said perhaps there is one aspect of flying that should be of concern – exposure to radiation from outer space, cosmic rays, in other words.
Buzzing along at high altitudes in a passenger jet exposes each passenger to a much higher dose of radiation than they would receive if they chose to travel by road, rail, or sea. Of course, the risk has to be offset with the exposure to vehicle pollution, for instance, and the much longer journey times (check-in security delays aside).
However, although we often hear about the exposure to low dose radiation air passengers receive, there is scant biomedical research looking at the effects and even then studies of the effects of cosmic rays are usually confined to before and after flight tests of aircrew, astronauts and cosmonauts.
Russian scientists at the Institute of Theoretical and Experimental Biophysics in Pushchino and the Institute of High-Energy Physics in Protvino, wanted to find out more about the chronic effects of aviation radiation and whether or not putative damage at the genetic level could be passed on to the next generation. They have now simulated the conditions of irradiation exposure during flight in mice. Their results, published this week in the aptly named International Journal of Low Radiation, make rather worrying reading.
Their simulations, which used the radiation field behind the concrete shield of the U-70 accelerator to mimic exposure during a flight at 12 or 16 km altitude, showed genetic problems in the bone marrow of offspring sired by male mice exposed to this simulated cosmic radiation. Moreover, the offspring did not have an adaptive response to the chronic, but low dose radiation.
In the last few years, new estimates of the health effects of cosmic irradiation, such as increased risk of cancer and genetic damage have shifted our perspective on radiation risks from early twentieth century hopes of a medical panacea to the idea that even low dose radiation is to be avoided at all costs.
The team points out that for someone flying 2000 hours each year, the equivalent dose of space radiation at altitude (10 to 17 km) is between 1.7 and 6 milliSieverts per day on average, amounting to a total exposure comparable to a worker in the nuclear industry or even substantially higher.
Perhaps this kind of research justifies some people’s fear of flying or more seriously maybe it gives us a reason to reduce our reliance on international air travel, which despite the possible economic costs might not be such a bad thing for the environment.
S. Zaichkina, O. Rozanova, G. Aptikaeva, A. Akhmadieva, H. Smirnova, S. Romanchenko, O. Vakhrusheva, S. Sorokina, A. Dyukina, & V. Peleshko (2009). Adaptive response and genetic instability induced in mice in vivo by low dose-rate radiation simulating high-altitude flight conditions Int. J. Low Radiation, 6 (1), 28-36