Dangers of Indoor Ozone

Alex Manning, Clean Air Advice
July 2006

What is Ozone?

Ozone (O₃) is a molecule consisting of 3 oxygen atoms; it is highly unstable and has a half-life. In hot water the half-life is about 20 minutes while in the air the half-life is about 2 hours. When the half-life expires the ozone breaks down into one oxygen molecule (O₂) and a single oxygen atom. This single oxygen atom is where the danger lies; it is called a "free radical" and must attach itself to or combine itself with something. Because 80% of our atmosphere is nitrogen, this is most likely the thing it will combine with, producing nitroxides (NO_x), which are toxic. While throat irritation is the most common symptom of NO_x exposure, the sensitivity to it varies widely according to the individual. Approximately 10-15% of the population is so sensitive to NO_x exposure that they cannot tolerate even tiny amounts.

How is Ozone Dangerous?

The chemical make-up of ozone discussed above is what makes it dangerous. The same properties that cause it to react with organic material outside your body cause it to react to the organic materials inside your body and possibly cause serious health consequences. Ozone can damage the lungs; even small amounts can cause chest pain, coughing, shortness of breath and throat irritation. Ozone exposure can also weaken the ability of the body to fight respiratory infections as well as worsen chronic respiratory diseases such as asthma. While sensitivity to ozone varies widely, both healthy people and those with respiratory difficulties can be susceptible.

Manufacturers of devices that produce ozone directly or as a side effect (some ionizing air purifiers) often use misleading terms to describe it, they use terms such as "pure air" or "energized air" to suggest that ozone is healthier form of oxygen, it is not. Ozone is a toxic gas very different chemically and toxicologically from regular oxygen. The National Institute of Occupational Safety and Health (NIOSH) recommends an upper limit to ozone of 0.10 parts per million (ppm) and that you only be exposed to that level for a maximum of 8 hours.

Even when following the manufacturer's instructions machines that produce ozone can quickly exceed the recommended levels in an occupied space. The danger depends on many factors such as: the size of the indoor space, the amount of material in the room with which ozone reacts and the amount of ventilation. In order for an ozone producing air cleaner to be effective, the amount of ozone needed in an indoor environment to remove most contaminants would greatly exceed health standards.

Recommendations

CleanAirAdvice.com recommends using proven methods of controlling indoor air pollution that do not produce ozone. These methods include controlling or eliminating pollutant sources, increasing outdoor air ventilation and using a proven air cleaner that does not produce ozone. If you are concerned about the level of ozone in your home of office you can purchase a home air test kit or hire a professional to test your air.

Related Articles

• Air Purifier and Air Cleaner Technologies
• Sharper Image Ionic Breeze and Oreck XL Air Purifier Tests Results
• What Are You Breathing?
• 12 Steps to Improve Indoor Air Quality