Air purifiers using negative ions have little effect
Air purifiers using negative ions have little air-cleansing effect and
even emit high-level ozone that can cause respiratory illnesses, a
Korean government test has found.
By contrast, those with filters proved effective at improving indoor air
quality and only discharged moderate levels of ozone, the government
said after examining 45 products on sale.
The demand for air purifiers has recently surged following the recent
yellow dust storms that blew across Korea from China and the
"well-being" trend.
Negative ion air purifiers account for around 20 percent of air cleaner
sales with another 52 percent of the market taken by filter purifiers,
said the Korean Ministry of Environment.
Negative ion air purifiers were known to create negative ions found in
mountainous areas and near waterfalls where the air is pure and healthy.
However, those on sale have only a minimal ability of collecting dust
and removing harmful substances, the ministry said.
They also generate ozone up to 10 times more than the permissible level,
the government said.
Nearly 70 percent of those gave off up to 0.580 ppm (parts per million)
ozone, a figure far higher than the permissible level of 0.05 ppm.
"We are concerned about possible damage to consumers," the ministry said
in its news release.
It refuted claims by some groups that low levels of ozone can act as a
powerful purification element.
"Research has found that ozone has little effect on getting rid of air
pollutants indoors," it said.
Therefore, it advised customers not to purchase products that advertise
the effects of removing pollutants and odor through generating ozone.
The ministry said it will further inspect all air purifiers.
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Air Purifiers
Air purifiers found not so pure
by PAT BRENNAN, The Orange County
Register May 11, 2006
Air purifiers found not so pure
UCI study says popular devices shown to produce unhealthy ozone.
By PAT BRENNAN
The Orange County Register
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.
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