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How much radiation does your phone emit?

Different types of cellphones emit different levels of radiation.TIMOTHY A. CLARY

With a new study out that shows a possible connection between cellphone exposure and certain types of cancer in rats, you may be wondering how much stuff you absorb from your cellphone — or your rat does from his.

The truth is, it’s not all that easy to tell.

Cellphones, televisions, and radio transmissions all emit electromagnetic radiation in the radiofrequency (RF) range. This kind of radiation is different from the kind emitted from X-ray machines or baggage screen equipment.

The human body absorbs energy from devices that emit radiofrequency electromagnetic radiation. The dose of the absorbed energy is estimated using a measure called the Specific Absorption Rate (SAR), which is defined as — this gets tricky — the power absorbed per mass of tissue, and has units of watts per kilogram of body weight (W/Kg).

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The Federal Communications Commission requires that phones sold in the United States have a SAR level at or below 1.6 watts per kilogram. SAR levels are measured with the phones placed in positions that simulate use against the head and near the body.

But a lower SAR doesn’t mean a phone is “safer,” according to the FCC. Its website states, “Many people mistakenly assume that using a cell phone with a lower reported SAR value necessarily decreases a user’s exposure to RF emissions, or is somehow ‘safer’ than using a cell phone with a high SAR value.”

Any cellphone legally sold in the US at or below the 1.6 watts per kilogram SAR level “is a ‘safe’ phone, as measured by these standards,” the FCC states. Still, critics argue that FCC standards are not realistic because they’re based on a man weighing more than 200 pounds, and standing 6 feet 2 inches tall. Most American adults, let alone children, are smaller than that — some quite a bit smaller.

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So, how does your phone measure up?

We compiled SARs in watts per kilogram of body weight for a few popular phone brands. Keep in mind that 1.6 W/Kg is the maximum legal limit in the US.

APPLE PHONES (source: Apple)

iPhone 6s Plus

Head SAR: 1.12 watts per kilogram of body weight as measured over one gram (W/Kg)

Body SAR: 1.14

iPhone 6s

Head SAR: 1.14

Body SAR: 1.14

iPhone 6

Head SAR: 1.08

Body SAR: 1.14

iPhone 5

Head SAR: 1.25

Body SAR: 1.18

iPhone 4s

Head SAR: 1.18

Body SAR: 1.19

iPhone4

Head SAR: 1.17

Body SAR: 1.11

SAMSUNG PHONES (source: Samsung)

Galaxy S7

Head SAR : 1.24 W/Kg

Body SAR : 1.59 W/Kg

Galaxy S6

Head SAR : 1.15 W/Kg

Body SAR : 1.16 W/Kg

LG PHONES (source: Phonearena)

LG G5

Head SAR: 0.82

Body SAR: 1.12

LG G4

Head SAR: 1.16 W/Kg

Body: SAR: 0.89 W/Kg

HTC PHONES (source: Phonearena)

HTC One M-9

Head SAR 0.55

Body SAR 0.71


David Filipov can be reached at David.Filipov@globe.com. Follow him on Twitter @davidfilipov.