Dubai The bills that you wrack up on your mobile calls shouldn't be your sole concern. Think of all the radiofrequency energy that you end up absorbing through all that talk time.

"Cell phone radiation can be a difficult thing to understand, and the methods used to shield and block it can be challenging for owners of cell phones," Ales Weiksler of Turkey's Sarlbore Enterprises Ltd said.

According to the Cellular Telecommunications Industry Association, specific absorption rate (SAR) quantifies the radiofrequency energy that is absorbed by the body while using mobile phones.

For a phone to pass US Federal Communications Commission certification, that phone's maximum SAR level must be less than 1.6 W/kg (watts per kilogram). In Europe, the level is capped at 2 W/kg while Canada allows a maximum of 1.6W/kg.

He said many studies have found a possible link between long-term (10 years or longer) cell phone use and brain tumours, decreased sperm count and other ailments.

If you're concerned about limiting your SAR exposure, you can take two easy steps. One is buying a phone with a lower SAR to feel comfortable, but there's no guarantee that it is safer. Also, during a call, the phone may never reach the listed SAR and the SAR can change constantly depending on several factors.

Cell phone radiation protection bag

Weiksler also recommends buying a cell phone radiation protection bag, which blocks 95 per cent of the radiation.

"Test results done by the Institute of Nonionising Radiation, Ljubljana, Slovenia, Bengaluru, New Hampshire, show a good reduction factor in SAR value when used with a shielding bag during exposure to 900 and 1800 MHz radiation of the mobile phone," he said.

At 900 MHz, the SAR value drops from 0.74 W/kg to 0.12 W/kg averaged over 10gm of tissue. On the other hand, the SAR value drops from 0.161 W/kg to 0.028 W/kg averaged over 10gm of tissue at 1800 MHz.

In the worst case scenario, he said the reduction in SAR value in the direction of the head is close to -8 decibel when using a phone bag. This means that only around 17 per cent of cell phone radiation reaches the head, more than 83 per cent of the radiation is shielded by the bag according to the principle of reflection.

The radiation shield bag, developed by Sarlbore, contains specially coated silver material. The bag comes in two sizes and is priced at €25 (Dh121) and €30.

He said the bag should always be placed between the phone and the body when making calls.