Indoor air purifiers that produce even small quantities of ozone may actually make the air dirtier when used at the same time as household cleaning products, scientists at UC Irvine have discovered.
Ozone emitted by purifiers reacts in the air with unsaturated volatile organic compounds such as limonene – a chemical added to cleaning supplies that gives them a lemon fragrance – to create additional microscopic particles, scientists found. Certain ionic purifiers emit ozone as a byproduct of ionization used for charging airborne particles and electrostatically attracting them to metal electrodes. Ozonolysis purifiers emit ozone at higher levels on purpose with the ostensible goal of oxidizing volatile organic compounds in the air.
This research appeared online this morning in Environmental Science and Technology.
“The public needs to be aware that every air purification approach has its limitation, and ionization air purifiers are no exception,” said Sergey Nizkorodov, assistant professor of chemistry at UCI and co-author of the study. “These air purifiers can not only elevate the level of ozone, a formidable air pollutant in itself, but also increase the amount of harmful particulate matter in indoor air.”
High levels of airborne particles can aggravate asthma and cardiovascular problems, and have been linked to higher death and lung cancer rates. Excess ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation.
Nizkorodov and students Ahmad Alshawa and Ashley Russell conducted their experiment in a sparsely furnished office with a floor area of about 11 square meters. They placed an ozone-emitting air purifier in the middle of the room along with a large fan to better mix the air. At timed intervals, limonene vapor was injected in the room. Samples of the air were taken about one meter from the purifier and analyzed for ozone and particulate matter levels.
The researchers tested two types of air purifiers – a commercial ionic purifier that emits about 2 milligrams of ozone per hour, and an ozonolysis purifier that emits approximately 100 milligrams of ozone per hour.
Continuous operation of the ionic purifier without limonene resulted in a slight reduction in the average particle concentration, while operation of the ozonolysis purifier resulted in no detectable effect on the particle level. When limonene was added to the room, the particle concentration shot up in both cases, on some occasions up to 100 times the original level. Adding limonene to the room when a purifier was not operating produced little change in the overall particle level.
The scientists also developed a mathematical model that precisely matched their experimental observations. This model can be used to predict whether a given air purifier will make the air dirtier in a given indoor environment.
Scientific data on indoor air purifiers will be important as officials begin the process of regulating air purifiers that emit ozone. In September 2006, California Gov. Arnold Schwarzenegger signed into law Assembly Bill 2276, requiring the California Air Resources Board to develop regulations that will set emission standards and procedures for certifying and labeling the devices.
“State regulators should set a strict limit on the amount of ozone produced by air purifiers to protect the public from exposure to unhealthy ozone and particulate matter levels,” Nizkorodov said.
The National Science Foundation funded this study.
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 25,000 undergraduate and graduate students and about 1,800 faculty members. The second-largest employer in dynamic Orange County, UCI contributes an annual economic impact of $3.7 billion.
Television: UCI has a broadcast studio available for live or taped interviews. For more information, visit www.today.uci.edu/broadcast.
News Radio: UCI maintains on campus an ISDN line for conducting interviews with its faculty and experts. The use of this line is available free-of-charge to radio news programs/stations who wish to interview UCI faculty and experts. Use of the ISDN line is subject to availability and approval by the university.
Jennifer Fitzenberger | EurekAlert!
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences