Re: Air purifiers producing ozone make air dirtier

[Guest guest]

KC,

Good info! It's also consistent with the studies by

Shaughnessy, PhD, University of Tulsa Indoor Air Program, that he

presented at the ASCR conference in Denver last November.

Dr Shaughnessy is also completing research on air quality and school

performance.

Carl Grimes

Healthy Habitats LLC

-----

> 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. "

>

> 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.

>

>

>

>

>

> FAIR USE NOTICE:

>

>

>

[Guest guest]

I enjoyed learning that too. Can't wait to see the study on schools Carl.

Re: [] Air purifiers producing ozone make air dirtier

KC,

Good info! It's also consistent with the studies by

Shaughnessy, PhD, University of Tulsa Indoor Air Program, that he

presented at the ASCR

Recent Activity

a.. 13New Members

Visit Your Group