Popular indoor air purifiers can sometimes emit dangerous levels of ozone, a lung-damaging pollutant, a UC Irvine chemistry professor says.
Some purifiers can create the indoor equivalent of a Stage Two smog alert.
The findings, similar to those in recent studies by the state Air Resources Board, suggest that the popular devices could be a significant source of indoor air pollution.
The worst of them, when used in a small, poorly ventilated room, could produce as much as three times the ozone levels recommended for outdoor exposure by state and federal air quality agencies.
"You have to put them in a smaller room to produce dangerous results," said UCI assistant chemistry professor Sergey A. Nizkorodov, whose study of the purifiers appears in the current issue of the Journal of the Air and Waste Management Association.
But if the purifiers are placed in a large, well-ventilated room, they have little or no effect, he said; far more air is moving through such a room than the purifier units can process.
The UC Irvine results showed potentially harmful buildup of ozone in small rooms even from low-emission units, Nizkorodov said.
"The major surprise of this particular research is that you can get high readings in ozone concentrations even from air purifiers that produce almost no ozone at all," he said.
Although ozone high in the stratosphere protects Earth's surface from harmful ultraviolet radiation, ozone at ground level, a component of smog, is a recognized health threat and is closely monitored by federal, state and regional regulators.
Regulators have imposed clean-air rules to reduce ozone emissions from businesses or vehicles, but no such standards exist for the indoor home environment.
So, while the purifiers exceeded federal and state thresholds for ozone in experiments done by Nizkorodov and his students, the companies that make them are not violating any laws.
The UC Irvine study involved so-called ionic purifiers, which emit ozone through the process of ionization - that is, causing airborne particles to become electrically charged.
Both the U.S. Environmental Protection Agency and the state Air Resources Board have warned consumers about possible risks of these air purifiers, although they remain unregulated.
The state Air Resources Board will hear a report from its staff on the issue May 25. And while the report is just an update on the purifier situation, the board could decide in the future to regulate the devices.
A bill to allow state regulation of indoor air purifiers was introduced in February by Assemblywoman Fran Pavley, D-Agoura Hills, and could come before the full State Assembly this week or next week, Pavley said.
"There is really no state agency that has any kind of regulatory authority, nor enforcement, over these products being sold," Pavley said Tuesday.
Consumer Reports magazine has also taken companies that sell air purifiers to task for high ozone emissions.
also read another MSNBC report on Air Purifiers:
