A search on the Internet turns up numerous papers that discuss studies on the effects of Wi-Fi radiation, admittedly, many of them on rats.

Still, the results of these studies show results contrary to what the AskST writer stated in his response. (Are there risks in sleeping next to a Wi-Fi router?; April 15)

The studies suggest that long-term exposure to Wi-Fi radiation can cause chronic kidney damage, damage DNA in reproductive organs, affect brain growth and development, increase oxidative stress levels that may lead to chronic disease, such as cancer, among other effects.

The exposure duration in these studies varied from one to 24 hours per day for several days and up to a year.

Although one cannot draw direct conclusions from the effects of Wi-Fi radiation on rats to humans, one must admit that there may be some undesirable effects.

Imagine placing a wireless router by the bed, exposing ones brain to Wi-Fi radiation for several hours a day, over years; can anyone claim that it is 100 per cent safe?

In the 1980s and 1990s, telcos claimed that there were no adverse effects from exposure to mobile phone radiation.

However, in May 2011, International Agency for Research on Cancer released a study on past cellphone users which showed that there is a 40 per cent increase in the risk of developing tumours for heavy cellphone users[8].

Hence, before any conclusive evidence clearly shows that Wi-Fi radiation is safe, we should take a precautionary step by keeping a safe distance from the router.

Basic electromagnetic theory tells us that an increase in separation distance from 10cm to 1m can potentially reduce the radiation level by a factor of 100.

Koh Wee Jin