Yes. Radiation emitted by cellphones is measured in terms of specific absorption rate (SAR) - the amount of radio waves absorbed by the body tissue when a mobile phone is in use. It is different for different phones. SAR is the highest when a user is talking.
All leading handset makers specify the SAR value in their user manual. These figures are also available on their websites.
What is a safe SAR level?
The lower the SAR value, the better. Both the Federal Communications Commission (FCC) and EU have stringent safety standards in place on cellphone radiation levels. For instance, cellphones can't be sold officially in the US if their SAR level exceeds 1.6 watts per kg (W/kg) while manufacturers in Europe must ensure that the maximum SAR level does not exceed 2W/kg.
Can a higher SAR level cause cancer?
Can't say. SAR limits are based on guidelines issued by the International Commission on Non-Ionising Radiation Protection which are endorsed by the World Health Organisation.
WHO classifies mobile phone radiation on the International Agency for Research on Cancer scale into "Group 2B", or possibly carcinogenic. That means that there "could be some risk" of carcinogenicity, so additional research needs to be conducted in the long-term, heavy use of mobile phones.
How to lower exposure to cellphone radiations?
Cellphones emit maximum radiation in areas where the network signal is weak. So try to use the phone outdoors, or move close to a window. Avoid lifts and basements.
Use a landline at home or in office. A wired handsfree is also safe. A Bluetooth headset too produces less radiation than a cellphone held directly to the ear.
Does India have SAR limit?
No. But the government now plans to cap SAR at 1.6 W/kg, in line with US rules.
What is the SAR of some popular handsats?
The Apple iPhone 4, at 1.17. Samsung Galaxy S2 has a SAR of 0.338, Samsung NexusS with 0.58 and BlackBerry Curve 8310 at 0.72.
Are there radiation norms for towers?
Yes. Currently, the radiation from 650,000 towers nation-wide should be less than f/200 watts per square metre. The government proposes to tighten this parameter further.
In 2008, mobile permits of all companies were amended to include self-certification of tower radiation levels to ensure compliance with WHO-endorsed guidelines. Each instance of non-compliance carries a penalty of 5 lakh.
What has been the government's response?
A government committee report submitted this year has concluded that radiation from mobile phones and towers poses serious health risks. "People chronically exposed to such radiation have reported unspecific symptoms, ranging from burning and tingling sensation in the scalp, fatigue, sleep disturbances, dizziness, ringing in the ears, headache and palpitation," the report said.
It suggested that children, adolescents and pregnant women should avoid excessive use of cellphones while people with medical implants should keep their cellphone at least 30 cm away while talking.