Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Indoor air purifiers that produce even small amounts of ozone may be risky for health

10.05.2006


Scientists verify that ionic and other air purifiers add to pollutants already in a room in levels that can exceed health standards



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, assistant professor of chemistry 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.

Jennifer Fitzenberger | EurekAlert!
Further information:
http://www.today.uci.edu
http://www.uci.edu

More articles from Health and Medicine:

nachricht Investigators may unlock mystery of how staph cells dodge the body's immune system
22.09.2017 | Cedars-Sinai Medical Center

nachricht Monitoring the heart's mitochondria to predict cardiac arrest?
21.09.2017 | Boston Children's Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>