By Kenton Shepard

 Although it's hard to make accurate, general statements about electronic air filters since they're not all the same, here are a few concerns...

Probably the main concern is ozone. Although it occurs naturally in the upper atmosphere where it protects living organisms by preventing damaging ultraviolet light from reaching the Earth's surface, too much exposure is toxic to humans. The FDA has set a safe limit of .05 parts per million for human exposure.

Excessive exposure can cause lung damage and especially vulnerable ar those with Asthma, lung disease and impaired imune systems. Hey! It's the same bunch who are vulnerable to problems from exposure to high levels of mold spores in indoor air!

There are air purifying systems which claim to work by producing ozone. Ozone generators should definitely be avoided.

Don't take my word, here's what the EPA has to say...

Some studies show that ozone concentrations produced by ozone generators can exceed health standards even when one follows manufacturer's instructions.

Many factors affect ozone concentrations including the amount of ozone produced by the machine(s), the size of the indoor space, the amount of material in the room with which ozone reacts, the outdoor ozone concentration, and the amount of ventilation. These factors make it difficult to control the ozone concentration in all circumstances.

Available scientific evidence shows that, at concentrations that do not exceed public health standards, ozone is generally ineffective in controlling indoor air pollution.

The concentration of ozone would have to greatly exceed health standards to be effective in removing most indoor air contaminants. In the process of reacting with chemicals indoors, ozone can produce other chemicals that themselves can be irritating and corrosive.

ELECTRONIC AIR FILTERS may or may not put out enough ozone to be harmful, depending on the manufacturer's design. They may require frequent cleaning of the plates, especially in homes with excessive (I don't know, you tell me) tobacco smoke or dust. Some brands may need to have the plates washed as often as every 3 days. In the meantime, they will be noisy, crackling as they pick up dust. More typical might be once every week or two. This does mean that you won't have to pay for new pleated filters 3 or 4 times a year.

The really great solution for those who can afford them are whole-house High Efficiency Particulate Air (HEPA) filters. These filters are usually installed in-line with the duct system and will remove over 99% of airborne particles down to 3 microns, which includes mold spores, so they're very good. Bit pricey though.