There is no doubt in my mind that cell phone texting or emailing are among the most dangerous driving distractions you can intentionally partake of. (Sure, you could worsen things by driving, drinking, speeding, and texting at the same time but I'm talking about just the hazards specific to cell phone use.)
Inspired by Jessica's recent post on cell phone cancer causation risk, I decided to do some cell phone EMF measurements (as pictured above) and also to do some thought experiments on this subject. What I learned was surprising.We're upgrading from older phones and I'm concerned about whether the more power-consumptive and visually oriented 3G "smart phones" offer more or less exposure to electromagnetic radiation. (I'd no more rely on Environmental Working Group measurements of cell phone risk than I would rely on Tea Partiers for insights into climate risk.)
What I found, comparing my 2-year old LG Rumor to my daughter's brand new smart phone, the Palm Pre, is that when in buzz-only mode, both tranceiving phones put out between 1.5 to 2 mG when they "rang." This was with the field strength meter held right alongside the phone, as in the photo above, with sensor parallel to antenna.
Set for max volume ring mode, however, the oldish LG Rumor put out 8 to 11 mG while the brand new Pre, held at approximately the same side-to-side distance from the meter, put out 3 to 5 mG when ringing. Right where you want it to be to be safe.
I next measured mG output with the tranceiving phone set to max speaker volume and the field strength meter held up close to each tranceiving phone speaker, as if the field strength meter were an ear.
The person calling - using the transponding phone - was asked to speak loudly, like those people walking down a busy city street almost shouting into their phone to make sure they are heard over the noise. (The ones who resemble schizophrenics.) My LG Rumor's mG output varied between 5 and 15 mG as the transponding phone user's voice modulated. An order of magnitude higher exposure than I'd prefer.
The new Pre's output when receiving an incoming call, with the caller talking loudly, varied between 3 and 5 mG - much better - and I was able to hear what was being said clearly. The result of just better speakers maybe.
Field strength falls off with the inverse square of distance from the actual source of EMF in a cell phone (mainly the sound driver in this case), just like brightness of light does with distance from its source. A centimeter difference in measurement distance from the cell phone speaker makes a very large difference in the mG reading.
To do this job right you'd have to integrate the EMF exposure readings over a curve representing how far listeners actually hold the phone from their ear, as a function of how loud the caller is talking, and how loud the background noise is, and how good the phone speaker is. You'd have to do it many times for each model and average for ages and language skills: to reflect how the behavioral aspect affects exposure.
Insights and conclusions.
I'm glad my daughter's new phone seems to put out a bit less radiation than mine does when she is "calling" someone.
The more important learning, I believe, was the insight that the smart phone in 3G mode is a highly visually oriented design that takes you away from talking and pulls you into a more computer-like interface, where speaker phone mode seems to make more intuitive sense and the radiation source is farther from your head.
A whole lotta texting and push emailing going on there. These operations take place in the 1.5 tyo 2 mG range; and the exposure is primarily to one's hand instead of to the ear and cranium or to the reproductive organs.
The transition to smart phone technology overall, iPhones being just one expression of that trend, means less phone-to-head EMF exposure while walking around or sitting at home.
However - and this is a very big deal 'however' - if legislators make it illegal to do the visual cell phone things while driving (texting, Googling, & emailing) but do not make cell phone talking come under a similar regulatory regime, they may be inadvertently increasing cranial exposure to electromagnetic radiation.
I can't yet decide whether speaker phone mode with a smart phone is an intermediate risk factor in driving. Probably so. The fact that these have built in GPS systems and louder, clearer speakers to offer the driving directions while you watch where you are going is a definite plus.