Ozone and Air Purifiers

To those of you that may have recently purchased an air purifier, or perhaps received one for Christmas, we pass on this bit of advice. If the air purifier has an “ion” button, you probably should have that button in the off position.

The ionizer releases negatively charged particles that are attracted to and bond with positively charged pollution particles. The combined particles become heavier and then drop out of the air and are collected on the filter. The creation of those negatively charged particles occurs through a process that unfortunately creates ozone, which has many of the same biologic consequences as particulate pollution.

Any man-made high-energy particle, like a negatively charged ion, can generate ozone as a by-product of the molecular reaction.

The federally mandated standards require that air purifiers not create ozone beyond a certain amount. Under these new regulations, the US Food & Drug Administration (FDA) requires that indoor air purifiers can only produce a maximum of 50 ppb (parts per billion) of ozone – which is much too high. Air ionizers today are often fitted with ozone sensors that monitor, suppress, and prevent high levels of ozone from being released. Nonetheless, that FDA standard, 50 ppb, is still way too high.

Our recommendation is that unless you are experiencing very high levels of particulate pollution, like a classic SLC winter inversion, don’t put the ionizer on while running the air purifier.