Ozone and Air Purification: Fact and Fiction

Ozone and Air Purification: Fact & Fiction

What is Ozone?

A chemist would answer that ozone is a single molecule composed of three atoms of oxygen, the third of which is unstable (or volatile) and therefore tends to separate and bond with other molecules.

An environmental scientist might tell you that ozone is the main component of urban air pollution, or that ozone high in the atmosphere protects our planet from harmful UV rays from the sun.

Your health care provider would certainly state that high indoor ozone levels can irritate sensitive lungs, and even affect healthy people at high concentrations.

Fact: The U.S. government's most stringent ozone safety threshold is .05 ppm (parts per million)

Because of ozone's role in air pollution-related health problems, its health effects have been studied extensively. Government agencies have established various safety thresholds for ozone exposure.

The National Ambient Air Quality Standard, established by the U.S. Environmental Protection Agency (EPA) is .08 ppm for outdoor ozone.

National Institute of Occupational Safety and Health recommendations and Occupational Safety and Health Administration regulations both establish ozone levels of 0.10 ppm as the safety threshold for workers on the job.

The most stringent standard, those of the U.S. Food and Drug Administration for indoor medical devices, specifies that ozone output be no more than 0.05 ppm.

Fact: The Blueair 501 tests at .003 ppm of ozone

Blueair's patented HEPASilent™ filter technology uses active ionization (particle charging) to capture and remove particles from indoor air. Ionization does produce trace amounts of ozone. However, Blueair systems are not associated with dangerous levels of indoor ozone. In fact, the opposite is true.

The Blueair 501 system was subjected to the Ozone Test outlined in section 37 of the Electrostatic Air Cleaner Standard, UL 867. The unit was positioned in the center of a closed 100 square foot room. The air in the room was tested continuously throughout 24 hours of normal operation.

Test probes measured only .003 ppm of ozone--far below the most stringent U.S. safety standards. The official test results appear in graph form below. The graph shows a sharp decrease in ozone concentration while the Blueair 501 unit is operating, with ozone levels climbing again after the system is shut down.

Fiction: Air purifier ionization chambers are the same as ozone generators

An oft-quoted EPA warning states: "Ozone generators that are sold as air cleaners intentionally produce the gas ozone ... Some manufacturers or vendors suggest that ozone will render almost every chemical contaminant harmless ... This is misleading." Blueair agrees with the EPA. We want to make it clear that none of our products are ozone generators.

The ionization chamber of a Blueair system is designed to charge particles in order to capture and remove them from indoor air. In contrast, ozone generators are designed specifically to create ozone. In tests of the two kinds of devices, the differences in ozone levels are dramatic.

In one EPA study, tests measured ozone concentrations of .20 to .30 ppm in rooms where some ozone generators were used. Such levels clearly exceed federal government safety standards and are a legitimate cause for concern. They are also many times higher than the Blueair's modest .003 ppm ozone test score. Ozone levels in a room where the Blueair system is used are well within the most stringent U.S. safety standards.

Fiction: Ionization always results in higher levels of indoor ozone

Tests demonstrate that HEPASilent™ filter technology actually reduces ozone in a sealed room, despite the trace amounts of ozone produced as a by-product of ionization. Blueair's design safeguards against excessive ozone production, and then removes ozone particles from the air, wherever they come from.

Blueair achieves these results in three ways:

The system produces ionization with as little current as possible. Ozone production is proportional to electrical current--the lower the current, the less ozone is produced. Using less current also reduces operating costs of the system.

The particle charging chamber inside a Blueair system is completely enclosed in steel. As ozone molecules collide with steel inside the chamber, many are stripped of their third oxygen atoms and become plain old oxygen.

Should any ozone molecules exit the particle charging chamber without bonding with the steel inside, they are then adsorbed by the carbon portion of the filter media.

Be an informed consumer

We know that people considering a Blueair air purification system are likely to want facts rather than fiction. The fact is that the EPA, the American Lung Association and other consumer groups and government agencies express legitimate concern about the health effects of concentrations of indoor ozone greater than .05 ppm.

We are certain that Blueair's low .003 ppm test results demonstrate that our HEPASilent™ filter technology is safe for human health. However, we encourage anyone with serious health concerns to discuss Blueair's ozone test results with a qualified health care provider.

Residential Air Cleaning Devices: A Summary of Available Information