Tuesday, December 16, 2008

Sunday, December 7, 2008

The Science of Japan: Is it really dangerous to use your mobile phone on the train?




If you take a bus or train in Japan you will nearly always see a “No Keitai” sign, and for good measure the bus driver or announcer will usually remind passengers to switch their phones to “manner mode” and to refrain from using them. I recall taking the bus home from work about a month after I arrived here, standing in the aisle and nattering away on my newly-acquired phone . . . only to realize—the ambient noise having dropped from its usual silent to “deathly silent”—every other passenger staring at me, and the bus driver furiously waving the dame! wave. And if the endeavours of the public transport personnel fail to persuade you, other passengers—particularly senior citizens—can be relied upon to enforce the no-keitai rule. One morning on the way to school I saw a young woman thumbing an email message into her phone, only to be greeted by a sharp “Gommen!” by a grumpy old man seated nearby. With nary a glance at the complainant, she calmly put the phone away.

Why is mobile phone use proscribed on public transport in Japan? Well, for one thing, it’s considered “rude” (as is talking at the boisterous volume to which we barbarous Westerners are accustomed) . . . and over here that should be the only reason you need. But it is also believed that the radio waves emitted by cellular phones can interfere with heart pacemakers, and therefore passengers are asked to switch their phones off in the vicinity of priority seats. Is this concern justified?

It is true that mobile phones emit electromagnetic energy. Many things do, including the Sun and the earth, as well as televisions and radios. Electromagnetic radiation is non-ionizing, meaning that it does not have sufficient energy, unlike ionizing radiation such as UV rays, to detach electrons from atoms and cause tissue damage. Exposure to very high levels of electromagnetic energy can cause tissue damage, according to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), but such levels would be well above what the general public encounters (in Australia at least; I can’t say whether it holds true for Japan). And worries about the risk of developing cancer from long-term exposure are generally what inspire people to protest the installation of towers or the use of handsets by children, but the jury is still out on how well-founded these concerns are. Nevertheless, the risk of tissue damage isn’t the main concern on Japanese buses and trains.

Concerns about cellular phones interfering with pacemakers and implantable cardioverter-defibrillators (ICDs) are well-founded, but the nature of the risk requires a little teasing-out. The purpose of a pacemaker is to ensure that the heart beats at an adequate rate, while a defibrillator will monitor the rate and rhythm of a heart and correct it if it is beating too slowly or too fast. Both essentially work by delivering electrical impulses to the heart muscles via electrodes, which in the case of the ICD is also used to detect heart activity. According to ARPANSA, both the signal transmitted from the phone’s antenna, and any magnets inside the phone can affect the operation of implanted medical devices, if the phone is held and operated sufficiently close to the implanted device. The organization therefore recommends that phones be kept at least 15cm from the pacemaker or ICD, which can be achieved if the patient avoids storing the phone in a pocket over site of the device, or if the patient uses the ear furthest from the site of the implant when he or she uses the phone. ARPANSA also notes that electromagnetic interference from mobile phones appears to be temporary; the device can be returned to its normal operation by simply moving the phone away.

So unless you’re on a really crowded train or bus, or unless you are actually sitting next to someone with an implant, it seems that he or she is unlikely to be harmed by your using your phone. Still, the host of the dinner party is unlikely to be harmed by your refusal to remove your shoes—unless you have been wading in toxic waste—and yet in the interests of maintaining peaceful and harmonious relations with your fellow creatures, and not looking like a complete and utter jerk, you are best advised to do as your host requests and take off your shoes. It is a good idea to do likewise on the train (put the phone away, that is; you can keep your shoes on), and save yourself much embarrassment—not to mention the ire of the ojiisan and obaasan, who can be far more intimidating than their diminutive appearance would suggest!

Matthew Stott, IANAS*
(*I Am Not A Scientist)