EDMONTON -- Research conducted by a team of chemists at the University of Alberta has discovered that the stand-alone, countertop humidifiers used during cold and dry winter months could be polluting the air in your home.

Assistant professor Ran Zhao says a device inside humidifiers called a piezoelectric transducer oscillates at a high frequency and breaks down the water into little droplets.

“Those are the droplets coming out of the mouth of this humidifier and that’s what you see by eye,” Zhao said. “Once the mist goes away, the water is all gone and what’s left behind are small particles that we cannot see by eyes but they are suspended in the air.”

Those fine particles, often referred to as PM 2.5, are an air pollutant that is a concern for people’s health. The majority are common salts or minerals that are dissolved in drinking water.

Zhao says using dirty water or water with potential bacteria can be very dangerous.

“The concentration of the particles can be equivalent to a polluted city like Beijing so the concentration gets really high,” he said.

Water filters helped reduce the particles by “about half but not completely.”

Instead, Zhao recommends using cleaner water or distilled water in your humidifier in order to reduce the number of particles created.