Radio waves are all around us.
There are natural radio waves from the sun and from lightning. There are man-made radio waves used for television, radios for music, two-way radios in aircraft, boats, taxis and emergency vehicles, microwave ovens, cordless phones, wireless Internet (Wi-Fi), cellphones, and now smart meters.
With all these radio waves around us, should we worry about their effect on human health?
Radio waves from microwaves are clearly not safe — they can cook you. The reason being that they are high power, in close proximity, and run for a prolonged period of time.
Alternately, AM radio waves are generally considered safe. Though they are high power and run almost all the time, they come from far away.
To check out the safety of radio waves, we have to crunch the numbers on power, distance and time.
The effect of power and distance is determined by the so-called “field strength” of the radio wave, measured as power per unit area (e.g. watts per square centimetre). For the same power, if the distance is doubled, the field strength drops four-fold. If the distance is increased 100-fold, then the field strength drops 10,000-fold.
The dosage is the combination of field strength and time. If you double the time of exposure, the dosage is doubled.
For example, a typical cellphone emits less than one watt of power, but can be very close (less than one centimetre away from your head) and may be used up to several hours per day.
As another example, a typical wireless Internet router or laptop emits less than one-tenth of a watt. It can be as close as half a metre away and may be used much of the day. The distance is 100 times further from your head than a cellphone, so the field strength from wireless internet is 10,000 times less. The effect of Wi-Fi is generally much less controversial than that of cellphones.
A typical smart meter emits about one watt of power, but is usually several meters away, and typically emits for only about a minute per day. So the field strength from a typical smart meter is about the same or less than that of Wi-Fi, but it is significantly less active than Wi-Fi.
The effect of smart meters on human health should be similar or less than the effect that Wi-Fi has on human health. The effect on individuals may vary. Just as some people sunburn quickly and others are more tolerant, it may be that your individual tolerance to radio waves may be lower or higher than others.
If you are comfortable with Wi-Fi in your home, then you need not worry about smart meters. But, if you choose to avoid using Wi-Fi in your home because you have health concerns, then you may want to avoid smart meters.
Peter F. Driessen is a professor in the department of electrical and computer engineering at the University of Victoria.