Air purifiers producing ozone make air dirtier

[Guest guest]

Air purifiers producing ozone make air

dirtierIndoor 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 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.

[Guest guest]

The article doesn't indicate when the UC Irvine study was done, but others have reported similar results at least a couple of years ago. Dr. Glenn on from University of Missouri-Rolla discussed his findings at the Healthy Indoor Environments Conference in Kansas City last year. Particle formation as a by-product of an ozone reaction was not limited to limonene (cooking oils also contributed, among others). Dr. on credited some of his counterparts that had done studies on this prior to his work. It's all good - just don't know that UC Irvine should be getting all the credit...

Curtis Redington, RS

Environmental Quality Specialist

City of Wichita Dept. of Environmental Health

Wichita, KS

Air purifiers producing ozone make air dirtier

Air purifiers producing ozone make air dirtierIndoor 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 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.

[Guest guest]

Does anyone else see how ludicrous the report of this study is, or is it me? Aren't we talking about ozonolysis of unsaturated hydrocarbons at a MOLECULAR level? This would not be detected with a laser light scattering particle counter and I don't think it would create condensation nuclei (or could it due to ionic charge on the oxidation products of limonene?) (Jeff, Tony?). There might be some kind of experimental confounder not known to be stirring up particles. Maybe having to do with "injecting" limonene vapor or the "large fan". Are these scientists stupid or am I missing something that wasn't explained?

And then, "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."

That statement is just silly.

How about this.... the high voltage circuitry thermally combusts VOC aerosol droplets and makes soot particles. It's not the ozone but the ozone generator?

Steve Temes

The article doesn't indicate when the UC Irvine study was done, but others have reported similar results at least a couple of years ago. Dr. Glenn on from University of Missouri-Rolla discussed his findings at the Healthy Indoor Environments Conference in Kansas City last year. Particle formation as a by-product of an ozone reaction was not limited to limonene (cooking oils also contributed, among others). Dr. on credited some of his counterparts that had done studies on this prior to his work. It's all good - just don't know that UC Irvine should be getting all the credit...

Curtis Redington, RS

Environmental Quality Specialist

City of Wichita Dept. of Environmental Health

Wichita, KS

Air purifiers producing ozone make air dirtier

Air purifiers producing ozone make air dirtier

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.â€

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 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.

[Guest guest]

Does anyone else see how ludicrous the report of this study is, or is it me? Aren't we talking about ozonolysis of unsaturated hydrocarbons at a MOLECULAR level? This would not be detected with a laser light scattering particle counter and I don't think it would create condensation nuclei (or could it due to ionic charge on the oxidation products of limonene?) (Jeff, Tony?). There might be some kind of experimental confounder not known to be stirring up particles. Maybe having to do with "injecting" limonene vapor or the "large fan". Are these scientists stupid or am I missing something that wasn't explained?

And then, "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."

That statement is just silly.

How about this.... the high voltage circuitry thermally combusts VOC aerosol droplets and makes soot particles. It's not the ozone but the ozone generator?

Steve Temes

The article doesn't indicate when the UC Irvine study was done, but others have reported similar results at least a couple of years ago. Dr. Glenn on from University of Missouri-Rolla discussed his findings at the Healthy Indoor Environments Conference in Kansas City last year. Particle formation as a by-product of an ozone reaction was not limited to limonene (cooking oils also contributed, among others). Dr. on credited some of his counterparts that had done studies on this prior to his work. It's all good - just don't know that UC Irvine should be getting all the credit...

Curtis Redington, RS

Environmental Quality Specialist

City of Wichita Dept. of Environmental Health

Wichita, KS

Air purifiers producing ozone make air dirtier

Air purifiers producing ozone make air dirtier

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.â€

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 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.