What is Ozone – O3
While there are many sound and important uses of ozone (such as for medical disinfection under controlled conditions), in general this is an idea which ranges from bad to dangerous in the home. Ozone is widely promoted by ozone generating equipment companies and cleaning services for use in indoor building environments to deodorize, disinfect, “kill” mold, and for “general health”.
Ozone generators are also promoted for use to reduce the level of airborne particles, pollen, animal dander, and allergens, ostensibly to improve indoor air quality for asthmatics and people with allergies.
Ozone or O3, or “trioxygen” is a molecule made of three oxygen atoms. In this form, and referred to as an “allotrope” of oxygen, ozone is an unstable gas – that means it breaks down into oxygen molecules.
While ozone is helpful in the upper atmosphere (filtering out UV light rays), in lower atmosphere, or in buildings, it is an air pollutant that is harmful to humans and other animals, and a gas that can oxidize or “burn” plants or various materials found indoors.
Ozone is widely used in industry in a variety of applications and can be of significant benefit and use when applied
A separate question remains, in some cases, of whether or not building occupants have been exposed or are being exposed to harmful ozone levels.
But nevertheless, ozone is a highly toxic gas. Now even highly toxic substances can be encountered safely. The main concern with ozone exposure is that the ozone concentrations to which people are exposedshould not average more than 0.1 ppm over an 8-hr day, andshould not exceed that value by more than a factor of 2 or 3 during the exposure.”
Exposure to a level you can smell or exposure to ozone over long periods at levels greater than 0.05 ppm for 24 hours at a time is likely to be dangerous: Health hazards to humans and animals occur and can be severe at ozone levels used for indoor cleaning purposes.
At least some people can smell levels of ozone down to 0.05 ppm. This odor-detection level is already half-way to the recommended limit. If you are generating ozone indoors, even at “low” levels a problem may be present. People become desensitized to odors in a short time, perhaps 20 minutes. So if you do not smell it, the ozone level could still be hazardous.
Lung irritation and infection. Breathing pain, coughing, wheezing, difficulty when exercising.
Permanent lung damage.
Aggravation of pre-existing asthma
Increased risk of lung illnesses such as bronchitis and pneumonia
Reduced breathing capacity.
Use of ozone to “remove” or “kill” mold is ineffective, not recommended, and may be dangerous. Even if ozone were applied at a concentration and for a duration sufficient to “kill” every mold spore in a building (which is a very dubious claim), depending on the mold genera/species present there is a good chance that the process leaves toxic and allergenic particles in the building.
“Higher concentrations can produce several kinds of toxic effects if exposures are sufficiently prolonged. Eye irritation (despite newspaper and TV accounts seemingly indicating otherwise) occurs only at concentrations high enough to result in other, more severe, toxic effects.
“Ozone is well known for its ability to eliminate certain odors. How this is accomplished is controversial. At concentrations just above the odor threshold, some odors do seem to vanish. The main reason for this may be ozone’s ability to desensitize the olfactory apparatus so that the odors can no longer be perceived. Some evidence indicates that this may be the case at least occasionally. Other evidence indicates that ozone may react with the odor-causing substances, eliminating them from the air (this is probably the only mechanism that operates when concentrations are below the odor threshold).
“Finally, some people have insisted that even if ozone does not paralyze the olfactory sense, its odor is such that it “masks” other odors. Perhaps all three mechanisms operate, each in its own area of effectiveness.
“As with all other materials, ozone has a dose-effect relationship with a threshold. That is, once the threshold dose has been exceeded, toxic effects are proportional to dose. For inhaled gases, dose is proportional to both time and concentration. If the duration of exposures cannot be controlled (as is usually the case), then the concentration must be kept low enough so that no injury will occur even from prolonged and repeated exposures. For ozone, that “threshold” concentration is 0.1 ppm.
“Ozone is a highly toxic gas but even highly toxic substances can be encountered safely. The main concern with this material is that concentrations to which people are exposed do not average more than 0.1 ppm over an 8-hr day, and do not exceed that value by more than a factor of 2 or 3 during the exposure.”
A second class of problems when ozone is misapplied indoors is the creation of lingering odors due to the oxidation effects of the highly reactive ozone gas while it was present.
In our OPINION, following ozone use as a “deodorant” if there is no lingering odor from oxidized materials in the enclosed space (a building, car, boat, RV, etc), and considering that ozone itself is so volatile that it does not hang around in the building, then its application probably did not create a problem for the building.