Have you ever heard of the SAR number? Well, the SAR is the call Specific Absorption Rate, a number that is on your mobile and indicates the radiation that our body absorbs when using our device when we communicate.
Since the massive use of mobile phones in modern society, the issue of how the radiation from terminals can affect our health, although it has often been presented more as a myth than a reality. Still, many people are concerned about whether the electromagnetic radiation produced by cell phone antennas can affect their biological processes to a greater or lesser extent. And for these people, there is the number , a value to take into account when purchasing a new terminal.
It is true, and it is mentioned by different studies, that electromagnetic waves from radios or mobile phones can affect the electrical activity of the brain during sleep, as well as sperm movement, and even also in the flight of bees, who can become disoriented when exposed to these waves. These studies, although minimal and with limited evidence, have been sufficient for certain countries to design SAR-based safety standards, since the higher this value, the greater the energy absorbed by the tissues. Each region establishes maximum SAR limits to market a mobile phone. For example, in the US the maximum SAR allowed is 1,6 W/kg (average over 1 g of tissue), while In the European Union the maximum is 2,0 W/kg (average 10 g) for head and trunk.
What is the SAR number and how is it measured?
Simply put, the SAR indicates how much radio frequency energy from a mobile phone is absorbed by our body. The higher the value, the greater the amount of energy absorbed. Technically, it is the rate at which the human body absorbs the RF energy emitted by the device. It is expressed in watts per kilogram (W/kg) and is measured by averaging the absorption in a specific tissue volume (typically 1 g in the US or 10 g in the EU).
SAR value measurements are made in the worst reasonable situation: with the mobile transmitting at maximum power, in the most unfavorable network, in the position where the mobile antenna most affects the body, and applying scenarios of calls and data transmission. Therefore, the declared value serves as a reference for regulatory compliance, while in actual use it is usually variable and minor.
Factors that cause SAR to vary from day to day
- frequency band: Higher bands can throw SAR values older under certain conditions.
- Potency of transmission: if the terminal increases power by poor coverage, the effective SAR may grow.
- Distance and placement: The closer the mobile phone is to the body (or in direct contact, such as in a pocket), the more RF is absorbed.
- Use of accessories: wired headset, hands-free or speakerphone reduce exposure by moving the antenna away from the head.
Regulation, limits and where to consult the SAR
In Europe, the limit of SAR for head and trunk is 2 W/kg, While for extremities is 4 W/kg. These limits are aligned with international recommendations (ICNIRP) and standards such as the Directive 2013 / 35 / EU on exposure to electromagnetic fields and the RD 1066 / 2001 for the general public. Manufacturers are required to comply with these limits already indicate the SAR value in manuals, labels and technical sheets.
You can consult the SAR in the manufacturer's website, in regulatory bodies such as the FCC or the competent European authority, and in independent lists. The authorities carry out periodic checks and if they detect non-compliance (for example, a value in limbs above the limit), they can demand temporary withdrawals o Software updates to correct it.
Samsung is among the healthiest on the market
Without going too far from the current commercial situation, Sony has just made public the SAR that its Sony Xperia Z will have, which is already being reserved in many countries, which will be 0,55W / kg, so users of this device can talk peacefully, as the radiation levels in this case are low. Although there's always the option of activating the hands-free mode to keep the radio away from your ear and brain, and turning off or activating airplane mode while you sleep.
Curiously, it is Blackberry that has been leading the worst SAR levels together with iPhone devices, with the best-selling models of both companies being the ones that come closest to the allowed limits of electromagnetic radiation. It seems that the firm that cares the most about this data is Samsung, with levels well below of the market average.
After reading about this phenomenon, maybe you would like to know the SAR number either your phone, or the phone you plan to buy. If so, here you'll find a specialized site that presents a fairly complete list of the value associated with each phone model. And in CNET.com There's an updated "TOP 20" of the cell phones that emit the least radiation. It's always a good idea to consult these files before deciding on one model or another.
Practical tips to reduce exposure
- Use hands-free or speakerphone whenever possible to increase the distance from your head. – Avoid putting your phone away attached to the body for long periods; best in a bag or on a table. – In areas of bad coverage, limit long calls (the phone increases power). – At night, if you don't need a connection, activate airplane mode or leave the device away from the bed.
Although the SAR is not a direct indicator of the health risk In real-life conditions, it is a useful reference to compare models and ensure that they meet the safety standardsChoosing a device with a low SAR, consulting official sources, and implementing simple habits to reduce exposure can help you use technology with greater confidence.