Air Purifier - Potential Ozone Hazard

Potential Ozone Hazard

As with other health-related appliances, there is controversy surrounding the claims of certain companies, especially involving ionic air purifiers. Many air purifiers generate some ozone, an energetic allotrope of three oxygen atoms, and in the presence of humidity, small amounts of NO_x. Because of the nature of the ionization process, ionic air purifiers tend to generate the most ozone. This is a serious concern, because ozone is a criteria air pollutant regulated by health-related U.S. federal and state standards. In a controlled experiment, in many cases, ozone concentrations were well in excess of public and/or industrial safety levels established by U.S. Environmental Protection Agency, particularly in poorly ventilated rooms.

Ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation. It can also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections—even in healthy people. People who have asthma and allergy are most prone to the adverse effects of high levels of ozone. For example, increasing ozone concentrations to unsafe levels can increase the risk of asthma attacks. Due to the below average performance and potential health risks, Consumer Reports has advised against using ozone producing air purifiers. Ozone generators used for shock treatments (unoccupied rooms) which are needed by smoke, mold, and odor remediation contractors as well as crime scene cleanup companies to oxidize and permanently remove smoke, mold, and odor damage are however considered a valuable and effective tool when used correctly for commercial and industrial purposes. However, there is a growing body of evidence that these machines can produce undesirable by-products as evidenced by an Environmental Protection Agency report that can be found at http://www.epa.gov/iaq/pubs/ozonegen.html

In September 2007, the California Air Resources Board announced a ban of in-home ozone producing air purifiers. This law, which took effect in 2009, will require testing and certification of all types of air purifiers to verify that they do not generate excessive ozone. This ban does not affect shock treatment ozone generators however for commercial and industrial use. Studies indicate that some ionic air purifiers produce ozone at 3.3 to 4.3 mg/h. Ozone generators used for shock treatments on the other hand produce over 3000 mg/h, the amount of ozone needed to create a "shock treatment" over a 6 hour period in a 100-200 sq ft room. The ozone generators which are subject to this ban use ceramic Mica plates that produce 300–400 mg/h of ozone and are intended to be used indoors in occupied rooms.