The
Importance of Indoor Air Quality
Indoor Air Purifiers May Be Health Risk
Purifiers That Produce Even Small Amounts Of Ozone May Be Risky
By: University of California at Irvine - Monday, May 22, 2006
Source: medicalnewstoday.com
In a small, poorly ventilated room, an indoor air purifier that
produces even a few milligrams of ozone per hour can create an ozone
level that exceeds public health standards, researchers at UC Irvine
have found.
Scientists also discovered that ozone produced by air purifiers
adds to ozone already present in any room -- a prediction that had
never been experimentally verified in a realistic indoor environment.
"These results mean that people operating air purifiers indoors
are more prone to being exposed to ozone levels in excess of public
health standards," said Sergey A. Nizkorodov, a chemistry professor
in the School of Physical Sciences at UCI.
Nizkorodov and UCI chemistry students Nicole Britigan and Ahmad
Alshawa published their research in the current issue of the Journal
of the Air & Waste Management Association. Their findings will
be studied by officials deciding how to regulate the distribution
of indoor air purifiers.
California lawmakers are considering legislation that would require
the California Air Resources Board to adopt regulations to reduce
emissions from indoor air cleaners by 2008. The state board and
the U.S. Environmental Protection Agency have issued advisories
discouraging use of air purifiers, but the devices remain on the
market because no agency has the outright authority to regulate
how much ozone they produce.
Indoor air purification has gained widespread popularity with the
surge in air pollution problems in urban areas.
Air purifiers target dust, pollen, airborne particles and volatile
organic compounds, which are emitted by a wide range of products,
including paint, cleaning supplies and pesticides. These pollutants
are believed to aggravate respiratory and other health problems.
Indoor air purifiers are advertised as safe household products
for health-conscious people -- especially those who suffer from
allergies and asthma -- but some purifiers produce ozone during
operation. For example, certain widely used ionic air purifiers,
which work by charging airborne particles and electrostatically
attracting them to metal electrodes, emit ozone as a byproduct of
ionization.
Depending on the design, some ionic purifiers emit a few milligrams
of ozone per hour, which is roughly equal to the amount emitted
by a dry-process photocopier during continuous operation.
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.
For this study, the research group tested several types of air
purifiers for their ability to produce ozone at 40 percent to 50
percent relative humidity in various indoor environments, including
offices, bathrooms, bedrooms and cars.
Placed inside a room, the air purifier was turned on, and the ozone
concentration buildup was tracked until a steady level of ozone
was reached. In many cases, indoor ozone levels far exceeded outdoor
safety guidelines, which in California are 90 parts per billion
for one hour and 70 parts per billion for eight hours.
The ozone level in some instances reached higher than 350 parts
per billion -- more than enough to trigger a Stage 2 smog alert
if similar levels were detected outside. A Stage 2 alert last occurred
in the Southern California coastal air basin in 1988.
Of the spaces tested, the largest increase in steady ozone levels
occurred in small rooms with little ventilation, especially those
containing materials that react slowly with ozone such as glossy
ceramic tile, PVC tile and polyethylene, which is used in plastic.
Ozone reacts quicker with materials such as carpet, cloth, rubber
and certain metals, destroying itself in the process.
People who operate purifiers indoors are more likely to be exposed
to ozone levels that exceed health standards because ozone from
these devices adds to ozone that already exists in the room.
Said Nizkorodov: "If 30 parts per billion of ozone exist in
the room because dirty outside air is leaking into the house, turning
on an air purifier that generates 50 parts per billion of ozone
creates a total ozone level of 80 parts per billion."
About AirUCI: Nizkorodov is a researcher with AirUCI -- Atmospheric
Integrated Research Using Chemistry at Interfaces -- a multi-investigator
effort led by chemistry professor Barbara Finlayson-Pitts to better
understand how air and water interact in the atmosphere and how
those processes affect air quality and global climate change. In
2004, UCI was awarded a total of $7.5 million over five years from
the National Science Foundation to establish AirUCI, an Environmental
Molecular Science Institute -- one of only seven currently funded
EMSIs dedicated to understanding at the molecular level how human
activity and nature contribute to global environmental problems.
About the University of California, Irvine: The University of California,
Irvine is a top-ranked university dedicated to research, scholarship
and community service. Founded in 1965, UCI is among the fastest-growing
University of California campuses, with more than 24,000 undergraduate
and graduate students and about 1,400 faculty members. The second-largest
employer in dynamic Orange County, UCI contributes an annual economic
impact of $3.3 billion. For more UCI news, visit http://www.today.uci.edu/
Contact:
Jennifer Fitzenberger
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