Health Effects

Ionizing radiation can damage the DNA in living cells. Damaged cells can either die immediately, be repaired, or mutate into cancer cells. Very few of the cells that are damaged by radiation develop into cancer. For those that do, the time period, between the radiation exposure and the development of a cancer can extend from 3-30 years.

The International Commission on Radiological Protection and the United Nation's Committee on the Biological Effects of Ionizing Radiation have studied large populations exposed to large doses of radiation (50 000 - 1 000 000 µSv). They concluded that the risk of health effects, such as cancer, is proportional to the dose received. In other words, the more dose you receive, the higher the risk of developing a cancer later in life.

At low doses (less than 6000 µSv per year) we don't know with certainty if radiation makes any difference to our health. Cancer development is very complex and depends on environmental, genetic and lifestyle factors. In the interest of safety, and as precaution, international organizations and governments regulate radiation exposure as if the risk of cancer was proportional to the dose, even at very low doses. The risk factors that they adopted are shown in the table below.

In summary, the risk of a fatal cancer is 5% for one sievert. For someone flying for forty years and receiving a dose of 5 000 µSv (0.005 Sv) per year, the additional risk of cancer is 1%. This is a very low risk. To put it into perspective, about 20-30% of the population dies of cancer. The increased risk of cancer from flying is very small.