Why is radiation so dangerous?

Jane Valencia

There are many different types of radiation – for example, visible light is actually a form of radiation. Some are more harmful than others. There are, on average, 15,000 radioactive particles travelling through your body every second. But with all this radiation exposure, why aren’t we all dying of cancer? It’s not the amount of radiation which you come into contact with – as every single one of these particles has the potential to cause cancer – it’s just the probability of that occurring is about one in 30 quadrillion. Only approximately one per cent of fatal human cancer is caused by these 30 trillion radioactive particles which pass through our bodies in a typical lifetime.

Ionising radiation has the energy to detach electrons from their associated atoms, therefore causing the atom to become positively charged. These charged particles are referred to as radicals and are highly reactive due to their unstable nature. Radicals are very important for certain processes in the body, such as the killing of bacteria. However, many unwanted effects, such as the mutation of cells, can be a problem. Scientists have found lots of evidence to suggest that these radicals cause mutations in cells, which can then give rise to cancer.