These are valid safety concerns because the ozone breaks apart molecules as part of the oxidation process, especially odor causing molecules. However, humans and pets are also made up of molecules, so ozone at high levels has the potential to irritate the eyes and respiratory system, especially those with asthma or COPD. Therefore, ozone should be used with caution.

In the recent past, some direct marketing companies sold air purifiers that produce ozone to consumers for use in occupied spaces. This created concern at the EPA, the FDA and the American Lung Association, which resulted in adverse publicity for the ozone industry. For decades prior to that time, ozone had been used commercially in the hotel, apartment, janitorial, water and fire damage remediation industries and many others, while spaces were unoccupied. So the state of California now has ozone restrictions for consumer air purifiers, and industrial ozone cleaners like the OdorFree have special labeling requirements. Beware of any type of air purifier that produces ozone and claims the product is for use in occupied spaces. Less

In the event these units were creating the extremely high levels of output claimed, the ozone would be causing unseen damage to vulnerable materials like speakers, leather furniture, electronics and other materials. Once ozone reaches a certain level, degradation and deterioration of materials begins. Ozone can do great things, but as with any substance, too much or excessive levels will create problems. And extreme levels are not required for permanent odor removal. Moderation is the key to a successful ozone treatment.

Ozone output levels can vary as a result of air temperature, humidity, barometric pressure and other factors. And there are no set standards or protocols for testing ozone production in milligrams per hour (mg/hr). A high output number is sometimes posted simply to attract buyers. Unfortunately, there is no authority to prevent this type of misinformation from being uploaded and distributed on the web.

The vast majority of portable ozone generators sold in the US for commercial use employ ceramic plates. These machines generally produce ozone at output levels of 300 mg/hr to 2,000 mg/hr for the purpose of permanently removing odors. Mica plates fell into disfavor by most companies decades ago because they were not serviceable. Recently, they have reappeared with internet sellers. Less

Many ozone generators have a very short lifespan. Always check the details of the warranty that a manufacturer provides. Ozone can be corrosive and all ozone producing elements build up a film on the plates that dramatically reduces output. Even plates protected by a filter will build up a microscopic film on the plates over time that causes the ozone production to drop. Beware of ozone plates that cannot be removed and cleaned by the end user.

This is especially true of mica plates because the material cannot be cleaned and alignment is very important. So the mica plates have to be permanently built into a handmade assembly for protection. Thus, the mica assembly can become the most expensive component, by far, in the entire unit. Once the inevitable microscopic film builds up on the mica plates or corrosion occurs, ozone output drops dramatically, making it a throwaway product or requiring a costly return to the factory. The most expensive part in the unit will need regular maintenance but cannot be serviced, so the warranty can become somewhat meaningless. Less