I’m sure you’ve seen the ads for ionic air purifiers that sharper image and other players sell. The actual benefit of these things is debatable at best. They function by blowing the room air over charged plates which supposedly charge the dust and pollen particles in the air and cause them to stick to the plates. How much of the dust in a room is actually removed is questionable. However, thanks to a new study funded by the National Science Foundation the charging of the air passing over the plates does cause the breathable oxygen gas to be converted to ozone. Ozone, while necessary for filtering out ultra-violet solar radiation, is definitely bad at ground level. High levels of of ground level ozone cause the creation of smog.

In a small and poorly ventilated room, the ozone adds to existing ozone and creates potentially unhealthy concentrations.

“People operating air purifiers indoors are more prone to being exposed to ozone levels in excess of public health standards,” said study leader Sergey Nizkorodov, a chemistry professor the University of California, Irvine.

Ozone can damage the lungs and cause shortness of breath and throat irritation, and it can also exacerbate asthma.

Nizkorodov and colleagues tested various air purifiers in homes, offices and cars. In many cases, ozone levels inside climbed above 90 parts per billion, exceeding California’s basic safety threshold. In some cases, ozone soared higher than 350 parts per billion, which if measured outside would trigger a Stage 2 Smog Alert, an event that hasn’t occurred in the Southern California coastal air basin since 1988.

So if the exorbitant prices that sharper image charges for products of dubious functionality, these things may actually be causing you lung damage. So save your money and change your furnace filter regularly. The furnace filter will probably pull more dust out of your air than this scam gadget anyway.