Ozone and Ionising Air Cleaners

Ozone is a molecule composed of three oxygen atoms. Ozone is found in the upper atmosphere (stratospheric ozone) and in the atmosphere (the air people breathe). The US Environmental Protection Agency (EPA) uses that phrase "Good Up High - Bad Nearby" to discern ozone in the upper atmosphere (which helps to protect by filtering ultraviolet radiation from the sun) from ozone in the atmosphere (which may cause health problems). Health effects of ozone may include throat and chest pain, shortness of breath, coughing, asthma aggravation, lung inflammation, and increased susceptibility to respiratory infection.

According to a Consumer Reports report entitled, "New Concerns About Ionizing Air Cleaners," some ionizing air cleaners may produce high levels of ozone during use. Ionizing air cleaners work by "imparting an electrical charge to the air, creating charged molecules known as ions, which are supposed to cling to airborne particles. Ozone is produced as a by-product when high voltage near the charging wires converts oxygen to ozone, which then exits the machine and flows into the room air. Some people mistake the ozone's sweet smell for a sign of cleaner air." (Consumer Reports, 22-3)

To determine the ozone output of selected ionizing air cleaners, Consumer Reports conducted testing in a sealed polyethylene room and in an open, well-ventilated lab. Testers measured the ozone output from each machine at distances of two inches and three feet. According to test results, each machine tested produced more than 50 parts per billion (ppb) of ozone. 50 ppb references the limit set by the FDA for levels of ozone produced by medical devices.

Currently, there is no Federal agency that sets standards for indoor ozone levels in homes. Ionizing air cleaners do not have to meet limits set by the Food and Drug Administration for medical devices; the FDA does not consider ionizing air cleaners as medical devices. Additionally, air cleaners do not have to meet EPA ozone limits as the EPA regulates outdoor and not indoor air. Manufacturers of ionizing air cleaners may submit air cleaning devices to a voluntary standard which includes a test to see if the device produces more than 50 parts per billion (ppb) of ozone.

Instead of purchasing an ionizing air cleaner, consumers may consider following EPA recommendations to control indoor air pollution, which include (in order of effectiveness) controlling the pollutant source, providing adequate ventilation and using proven air cleaning methods such the use of mechanical filters installed in ductwork.

Sources:
"New Concerns About Ionizing Air Cleaners." Consumer Reports, May 2005, 22-25.
"Ozone Generators that are Sold as Air Cleaners: An Assessment of Effectiveness and Health Consequences." [online]. US Environmental Protection Agency (EPA). Available from http://www.epa.gov/iaq/pubs/ozonegen.html

Debbie Wilburn is County Agent/Family and Consumer Science Agent with the Hall (770)535-8290 and the Forsyth (770)887-2418 County Extension Service.

http://accesswdun.com/article/2005/7/129655