Specific Absorption Rate (SAR) for Cellular Telephones

• Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the body when exposed to a radio frequency (RF) electromagnetic field; although, it can also refer to absorption of other forms of energy by tissue, including ultrasound.
• It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).SAR is usually averaged either over the whole body, or over a small sample volume (typically 1 g or 10 g of tissue). The value cited is then the maximum level measured in the body part studied over the stated volume or mass.
• United States Federal Communication Commission (FCC)  has adopted limits for safe exposure to radiofrequency (RF) energy. These limits are given in terms of a unit referred to as the Specific Absorption Rate (SAR), which is a measure of the amount of radio frequency energy absorbed by the body when using a mobile phone.
• The FCC requires cell phone manufacturers to ensure that their phones comply with these objective limits for safe exposure. Any cell phone at or below these SAR levels (that is, any phone legally sold in the U.S.) is a "safe" phone, as measured by these standards. The FCC limit for public exposure from cellular telephones is an SAR level of 1.6 watts per kilogram (1.6 W/kg)
• India has taken a leaf out of the United States Federal Communication Commission (FCC) by adopting a stricter SAR limit of 1.6 watts per kilogram averaged over a volume of 1 gram of tissue for the head. The SAR value currently in effect is 2 watts per kilogram averaged over a volume of 10 gram of tissue. Another significant aspect is the requirement to compulsorily mention the SAR value on every handset so that consumers are aware of it. Until now, companies have been tucking this information in the handset manuals or their websites. But the worse culprits are the cheap phones sourced from a few countries that have much higher emission levels than the currently permitted SAR limit.