The everyday use of Wi-Fi has some people concerned about the impact low levels in schools, businesses and homes can have over a long period of time.

Electromagnetic radiation is given off by Wi-Fi or wireless connections in things like cordless phones, wireless Internet routers and some baby monitors.

Rob Metzinger is the president of Safe Living Technologies. He says "wireless exposures in Canada are amongst the highest in the world."

He tests exposure levels to Wi-Fi and other wireless technologies in business and homes.

The issues is growing, he says, because "I work with people who are very sensitive to this type of radiation so they need met o get everything out of their living environment."

The guidelines he follows are much stricter than those set out by Health Canada's Safety Code 6, which limits human exposure to radiofrequency electromagnetic fields.

He says it's because he is looking at low level exposure over a long period, and "Hopefully in the future they can amend Safety Code 6 in order to account for this different type of exposure."

However, Health Canada maintains their level is safe for the public, and the radiofrequency energy emitted by Wi-Fi equipment is extremely low and not associated with any health problems.

However, some recent studies, including one from Canada, say laptops in Wi-Fi mode sitting on a man's lap for an extended period may affect fertility.

Some research also indicates people are affected by Wi-Fi differently, with some showing symptoms similar to an allergic reaction.

It is studies like those that have prompted some parents to pull their children out of schools over concerns about Wi-Fi exposure.

Dr. Magda Havas is a professor at Trent University, and she's also concerned about the impact on students.

She says "There's a subset of people who have developed a sensitivity. These people cannot go into a coffee shop that has Wi-Fi, and if more and more people are exposed to it, my concern is that a growing population will develop sensitivity."

It is a concern especially among children, she says, for whom exposure to toxic chemical or radiation in the environment is much more dangerous.

Metzinger says he has sold hundreds of sets of test equipment to school boards in Canada and the U.S.

And those sales are likely to continue to increase as more everyday technology uses Wi-Fi, such as Ontario's new Smart Meters, which are being installed across the province.