Air Purifier Advice

Air Purifiers That Help and Those That Don’t

Indoor air pollution is a serious health hazard that needs to be addressed. For those concerned with reducing harmful pollutants in their homes, air purifiers, along with controlling the sources of pollution and ensuring adequate ventilation, can help keep these unhealthy chemicals and objects down to a minimum. However, not all indoor air purifiers are created equal. Some are more effective than others, and some, unfortunately can cause bigger air quality problems than they solve.

“Ozone is a toxic gas with vastly different chemical and toxicological properties from oxygen.” – United States Environment Protection Agency

Smart buyers will research the effectiveness of the various types of air purification systems available on the market. This article will focus on one specific problem that some kinds of “purifiers” produce: ozone. Some companies produce air cleaners that deliberately introduce significant quantities of ozone into your home. But ozone is an extremely unhealthy substance that can cause significant health problems for people who are exposed to it. If pumping a pollutant into the air to counteract pollutants sounds odd to you, you’re right.

The purpose of this article is to explain why, if you are shopping for an effective, high-quality air cleaner, you should not purchase any air filter that generates ozone. First we will discuss ozone: what it is, and what effects the Environmental Protection Agency has found it can have on the human body.

What is Ozone?

Ozone is a molecule that is made up of three oxygen atoms. Therefore it is often abbreviated as O3, and you will occasionally hear it called “trioxygen.” Many people will be familiar with the term “ozone” from hearing about the ozone layer that exists in the earth’s stratosphere. Up there, some ten or more miles above the planet’s surface, ozone is helpful to humans; it serves to block out harmful radiation emanating from the sun. In fact, without it, life as we know it would not be possible. One sometimes hears of ozone holes, where the ozone has been depleted and radiation enters the atmosphere in higher than normal levels.

(structure of an ozone molecule, 3 oxygen atoms and their charges – Image Source: Wikipedia)

Are Manufacturer Claims Legitimate?

The impression people receive is that ozone is a beneficial substance, and, as far as the ozone layer goes, that is certainly the case.  Manufactures of ozone-generating devices play on this perception, as well. They may also use enticing terms like “energized oxygen” to describe ozone as just another form of the oxygen we breathe. However, chemistry just doesn’t work like that: to quote the EPA’s report “Ozone Generators that Are Sold as Air Cleaners,” ozone is “a toxic gas with vastly different chemical and toxicological properties from oxygen.”

However, someone who is only informed about the role ozone plays in shielding us from radiation may think of ozone solely in terms of its benefits and not be aware of the dangerous results that close contact with it can have. It is possible to speak of “good” ozone and “bad ozone,” but the only difference between the two is location. If you are breathing it, it is always the bad kind. In other words, when it comes to ozone, the EPA wants us to remember the slogan “good up high, bad nearby.”

“At ground level, ozone is a harmful pollutant.” – Environmental Protection Agency

Ozone is released by many pollution sources, such as car exhaust, chemical plants, and refineries, and is one of the substances monitored by the EPA under the Clean Air Act. The last thing you need is a so-called air purifier that pumps such a chemical directly into your home’s air.

Next, we will briefly discuss what it is about ozone that makes it so bad for your health.

Why is Ground-Level Ozone Unhealthy?

As we said above, ozone consists of three oxygen atoms that have bonded together. Usually when we speak of “oxygen,” we do not refer to a single oxygen atom but rather a molecule made up of two oxygen atoms, O2. It is this form of oxygen that humans and animals need to stay alive. This is because oxygen atoms naturally tend to bond with each other. A molecule consisting of two oxygen atoms is stable; the two atoms are tightly bound together and are not easily separated.

Ozone Bonds to Your Lungs

This is not the case with ozone. The third oxygen atom can become detached relatively easily, leaving instead one normal oxygen molecule with two atoms, and a single oxygen atom that is not bonded to anything else. It is this tendency to decay that makes ozone so dangerous.

Single oxygen atoms “want” to bond to something else, so to speak, and they will not only do so with one another. They can also attach themselves to organic compounds, such as those found in your body. When they do so, this completely changes the properties of whatever the oxygen atom has bonded with. The final result of the process for you, if you inhale ozone, is damage to the matter that makes up your body. This is why the EPA states that, however necessary ozone is in creating the conditions that allow life on Earth, “at ground level, ozone is a harmful pollutant.”

In short, by breathing the air in an ozone-rich environment, you are ingesting a substance that will wreak havoc on your lungs. Now let us take a look at the specific problems that arise when you are exposed to ozone.

The Negative Health Effects of Ozone

Breathing in ozone can damage your lungs and have a number of ill consequences. The following list is based on the EPA’s findings regarding the health effects of ozone exposure:

1. Causes Coughing –  Ozone can make you cough, irritate your throat, leave you short of breath, and cause aching in your chest, even in relatively low doses.
2. Inflames Your Lungs –  It can damage your respiratory system by inflaming the cells that line your lungs.
3. Possible Permanent Lung Damage –  It can cause permanent damage to the lungs themselves in some instances. For example, if a child is exposed to ozone, it can interfere with the growth and development of the lungs. In adults, it can accelerate the deterioration of the lungs that comes naturally with aging.
4. Worsens Asthma – If someone with asthma inhales ozone, it can worsen his or her condition even further.
5. Worsens Emphysema and Bronchitis – Likewise, ozone can exacerbate other lung diseases as well, including emphysema and bronchitis.
6. Interferes With Immune System –  It can interfere with the functioning of the body’s immune system around the lungs, leaving you more vulnerable to airborne infections because your body is less capable of fighting them off.
7. Damage Continues – Some of the immediate irritation caused by ozone may subside after a few days of exposure, even if you are still inhaling it at the same levels. Though this might feel like a relief, it can lull us into a false sense of security. The EPA pamphlet “Ozone and Your Health” (PDF) states that “ozone continues to cause lung damage even when the symptoms have disappeared.”

As you can see, it would be wise to take care to avoid ozone whenever possible. But if ozone is so unhealthy, why do some air purification manufacturers make products that deliberately introduce it into your home? We will now move from discussing ozone in general to examining the effectiveness and safety of these systems.

Ozone-Generating Air Purifiers: Do They Work?

The idea behind air cleaners that produce ozone is based on ozone’s reactive properties. As we said earlier, ozone is highly unstable and will break apart, leading to further chemical reactions. Makers of ozone generators suggest that this process will destroy many of the unhealthy airborne chemicals in your home. But the EPA, which has done considerable investigating into the effectiveness of ozone generators, disagrees, and lists three problems with these claims.

Ozone Air Purifiers Are Largely Ineffective

1. Many pollutants are not damaged by ozone – The EPA goes so far as to say in “Ozone Generators that Are Sold as Air Cleaners” that “for all practical purposes, ozone does not react at all with such chemicals.” Ozone may quickly damage you, but that does not mean everything is equally vulnerable to it.
2. Creation of new pollutants – When it comes to those things that ozone does neutralize, the reaction that destroys the original pollutant sometimes just creates new pollutants, leaving the air hardly any cleaner than it was before. One report prepared by the EPA suggests, for example, that “ozone is also believed to react with acrolein, one of the many odorous and irritating chemicals found in secondhand tobacco smoke.”
3. Ineffective Particle Removal – Ozone does not do anything about unhealthy particles in the air that comprise a good deal of the total amount of indoor air pollution. This would include pet dander or dust, for example. Traditional air filters are usually most effective at getting rid of particulate pollution, which means that if someone buys an ozone generator instead, he or she is missing the opportunity to do something significant to reduce pollution.

Beyond these points, further studies cited by the EPA have also indicated that ozone generators do nothing against many odor-causing substances commonly found in the home. One report, published in the official journal of the American Society of Heating, Refrigerating, and Air Conditioning Engineers, found that “body odor may be masked by the smell of ozone but is not removed by ozone.”

Also, although there does exist some evidence indicating that ozone can be used to combat viruses and living pollution sources such as bacteria and mold, for this to have any measureable impact, the ozone would need to be present in qualities far above what humans can safely tolerate.

To sum it all up, ozone generators just don’t work. That alone is enough reason to avoid buying them, of course. But on top of that, there is the question of safety, and on these grounds, as well, ozone generators fail.

Ozone-Generating Air Purifiers: Are They Safe?

In fairness, different kinds of ozone generators produce different amounts of ozone. Some, if used exactly as recommended by the manufacturer, may not create enough ozone to cause any damage. For all the reasons discussed in the previous section, these purifiers are still useless as a means of cleaning the air, but at least they aren’t directly contributing to the problem they are advertised as solving.

Unfortunately, the EPA has found that, with some other brands of ozone-generating devices, “concentrations of ozone considerably higher than [recognized public health standards] are possible even when a user follows the manufacturer’s operating instructions” to the best of his or her ability. There are simply too many factors that can spring up and cause an increase in ozone exposure. The size of the room, whether doors or left open or closed, and the exact makeup of the air around the ozone generator all affect how concentrated the ozone will become.

Also, it is very difficult to take into account other sources of ozone (cars, factories, etc.) that may be nearby. It is possible that an ozone generator will not on its own produce enough ozone to be harmful, but when combined with these other sources, the amount of ozone crosses the danger threshold.

In conclusion, even if ozone generators did work as they are intended to do, and as they are marketed as doing, they just are not safe enough to put in your home.

What Are the Alternatives to Ozone Air Purifiers?

All the evidence indicates that ozone generators are neither effective nor safe. Therefore, first of all, if there are any ozone-generating devices in your house, turn them off at once. They are at best doing no good, and at worst they are adding to the pollution that you purchased them to reduce.

If you are concerned about indoor air quality, the good news is that there are plenty of air purification systems available for houses and apartments that do not produce any ozone at all. There are much better and safer methods of eliminating toxins from the air, and the EPA acknowledges that some other kinds of air purifiers have a role to play in cleaning up the air you breathe at home.

Mechanical Air Purifiers The Best Choice

“Mechanical” air purifiers are those that use filters to capture particles that would otherwise float in the air, possibly to be inhaled by humans. These are likely to be the smartest choice, but be aware that they will not help against gaseous pollutants, only solid ones, especially smaller particles that remain in the air for an extended period of time. Even with a good air purifier, controlling the sources of pollution and making sure your home is well-ventilated are necessary steps.

Note that there are also electronic air purifiers, such as ionizers. However, these are not recommended because they, too, produce ozone, whether they were intended to do so or not. To take the most famous example, the makers of the well-known Ionic Breeze brand of purifiers eventually went bankrupt due to reports that their product produced high levels of ozone. Therefore, mechanical filters will be the best option for most people.

Summary and Conclusion

Ozone, a molecule consisting of three oxygen atoms, may help preserve life on earth when it is up in the stratosphere, but it also poses health risks for people when they inhale it. Although some companies sell “air purifiers” that supposedly fight toxic chemicals in the air with ozone, the truth is that these devices are ineffectual and sometimes downright dangerous. They can contribute to lung diseases, worsen pre-existing problems, and damage lung tissue. With so many potential health hazards floating around in your home’s air, the last thing you need is add ozone into the mix.

Therefore, such devices should be avoided in favor of air filtration systems that do not produce ozone. A high-quality air purifier, operating on sound scientific principles, is an important weapon in the fight against indoor air pollution. And happily, there are good, effective air purifiers readily available to keep your home’s air breathable.

Bottom Line – Before you purchase an air purifier, make sure that it does not produce ozone!

List of California Approved Air Purifiers (No Ozone Generated During Operation)

Brand Model Name (Model Numbers) Date Notified EO Number Filtrete™ Ultra Quiet Room Air Purifier (FAP01-RS)  Mechanical 02-26-2009 G-09-004 Filtrete™ Ultra Clean Room Air Purifier (FAP-02, FAP02-RC, FAP02-RS, FAP02-RY, FAP-03, FAP03-RC, FAP03-RS, FAP03-RY) Mechanical 02-26-2009 G-09-004 Filtrete™ Ultra Quiet Room Air Purifier (FAP00-RS)  Other* 12-02-2009 G-09-118 Aerus (Blueair AB) Guardian Air Other* 05-12-2010 Air King® 42″ Wind Curve (9554) Other* 11-12-2009 G-09-102 48″ Tower Fan (9820, 9820A) Other* 11-12-2009 G-09-102 Atmosphere (Access Business Group) Atmosphere™ Air Purifier (101076) Mechanical 04-27-2009 G-09-014 Blueair AB Blueair (403, 450E, 503, 550E, 603, 650E) Other* 05-12-2010 Blueair (203, 270E) Other* 07-09-2010 Electrolux (Winix) EL500A Mechanical Pending** EL500AX EL500AZ Other* Pending** Febreze®/True Air (Hamilton Beach) Direct Plug-In Odor Eliminator (04530C, 04530F, 04531C, 04531F) Mechanical 12-17-2009 G-09-103  GE (Woongjin Coway) Small Air Purifier (AFHC09AM) Mechanical 05-04-2009 G-09-015 Large Air Purifier (AFHC21AM) Mechanical 05-04-2009 G-09-015 Super Air Purifier (AFHC32AM) Mechanical Pending** Holmes (Jarden Consumer Solutions) HAP9240-U  HAP9412-U HAP9424-U Mechanical 03-16-2010 Honeywell® by Kaz® enviracaire® Programmable True HEPA Air Purifier (50310, 50311) Mechanical 03-20-2009 G-09-006 enviracaire® True HEPA Air Purifier (50100, 50101, 50150, 50200, 50250, 50251, 50300, 50300-CST) Mechanical 03-20-2009 G-09-006 enviracaire® QuietClean (60001 ) Other* Pending** HEPA-Type Tabletop Air Purifier (16200) Other* Pending** HEPAClean Compact Tower (HHT-055) Mechanical 06-01-2010 HEPAClean Tower (HHT-155) Mechanical 06-01-2010 HEPAClean Air Purifier Dual Pack (HHT-1500) Mechanical 06-01-2010 HEPAClean Tabletop Air Purifier (HHT-011) Other* Pending** HEPAClean Tower Air Purifier (HHT-080, HHT-081) Other* 07-28-2009 G-09-006 HEPAClean Tower Air Purifier (HHT-085-HD) Other* 03-23-2010 G-10-014 HEPAClean UV Tower Air Purifier (HHT-145, HHT-149,  HHT-149-CST) Other* 07-28-2009 G-09-006 HEPAClean UV Tower Air Purifier (HHT-149-HD) Other* 03-23-2010 G-10-014 Pet Clean Air Air Purifier (HHT-013, HHT-016-MP) Mechanical Pending** QuietCare™ True HEPA Air Purifier   (17007, 17007-HD) Mechanical 01-27-2010 QuietCare™ True HEPA Air Purifier   (17200, 17205, 17205-CST) Other* 01-27-2010  G-10-014 QuietCare™ True HEPA Air Purifier with permanent filter (17000, 17000-19, 17000-S, 17000BB, 17005, 17006, 17000N-KOL) Mechanical 03-20-2009 G-09-006 QuietCare™ True HEPA Air Purifier with permanent filter (17005-S) Mechanical 08-12-2009 G-09-006 QuietClean Air Purifier (HFD-015, HFD-1101, HFD-110, HFD-112, HFD-116C ) Other* 06-30-2009 G-09-006 QuietClean Air Purifier (HFD-135, HFD-137, HFD-139) Other* Pending** QuietClean Air Purifier with permanent filter (HFD-120-Q, HFD-120-Q-1) Other* 05-29-2009 G-09-006 QuietClean Air Purifier with permanent filter (HFD-122C, HFD-015C) Other* 10-19-2009 G-09-101 QuietClean Antibacterial Air Purifier (HFD-130) Other* Pending** QuietClean Compact Tower Air Purifier (HFD-010) Other* Pending** QuietClean Tower Air Purifier (HHT-090) Other* 03-04-2010 G-10-014 QuietClean Tower Air Purifier (HFD-123-HD) Other* 03-23-2010 G-10-014 QuietClean UV Tower Air Purifier (HHT-215, HHT-217, HHT-219) Other* Pending** SilentComfort™ True HEPA Air Purifier (18155, 18150) Mechanical 03-20-2009 G-09-006 True HEPA Air Purifier (50255-HD) Mechanical 03-23-2010 G-10-014 True HEPA Air Purifier with permanent filer (50150-S, 50250-S) Mechanical 10-19-2009 G-09-101 True HEPA Compact Tower (HPA-050) Mechanical 06-02-2010 True HEPA Tower (HPA-150) Mechanical 06-02-2010 Hunter Fan HEPAtech Air Purifier System (30054, 30055, 37055) Mechanical 06-30-2009 G-09-005 HEPAtech   (30057,30059, 30710, 30711, 30730, 30748, 30750) Other* Pending** Permatype Air Purifier  (30835, 30836, 30837) Mechanical Pending** Programmable HEPA Air Purifier (30401) Mechanical 06-30-2009 G-09-005 QuietFlo® HEPA Air Purifier (30245) Mechanical 06-30-2009 G-09-005 QuietFlo® HEPA Air Purifier (30525) Mechanical 03-16-2009 G-09-005 QuietFlo® Plus Air Purifier (30785, 30780 to 30789) Mechanical 06-30-2009 G-09-005 QuietFlo® True HEPA Air Purifier (30090, 30095) Mechanical 03-16-2009 G-09-005 SOLO2 (30030 to 30039, 30040 to 30049, 37030 to 37039 ) Mechanical 06-30-2009 G-09-005 IDYLIS (Woongjin Coway) Air Purifier (IAP-10-100, IAP-10-100C, IAP-10-125, IAP-10-125C, IAP-10-150, IAP-10-150C, IAP-10-200, IAP-10-200C, IAP-10-280, IAP-10-280C) Mechanical Pending** IQAir® Cleanroom H13™ (1EB UD0 KGU / 1EB UD0 KGB) Mechanical 04-15-2010 Dental Hg™ (1D0 UA0 IGU, 1DA UA0 IGU) Mechanical 04-15-2010 Dental Pro™ (1D0 UA0 IGU, 1DB UA0 IGU) Mechanical 04-15-2010 GC™ AM (1C0 UB0 HGU, 1CA UB0 HGB) Mechanical 04-15-2010 GC™ ChemiSorber (1C0 UB0 HGU, 1CB UB0 HGB) Mechanical 04-15-2010 GC™ MultiGas (1C0 UB0 HGU, 1CC UB0 HGB) Mechanical 04-15-2010 GC™ VOC (1C0 UB0 HGU, 1CD UB0 HGB) Mechanical 04-15-2010 GCX™ AM (1F0 UB0 LGU, 1FA UB0 LGB) Mechanical 04-15-2010 GCX™ ChemiSorber (1F0 UB0 LGU, 1FB UB0 LGB) Mechanical 04-15-2010 GCX™ MultiGas (1F0 UB0 LGU, 1FC UB0 LGB) Mechanical 04-15-2010 GCX™ VOC (1F0 UB0 LGU, 1FD UB0 LGB)  Mechanical 04-15-2010 HealthPro® (1BA UA0 CGU) Mechanical 04-15-2010 HealthPro® Compact (1AG UA0 RGU) Mechanical 04-15-2010 HealthPro® Compact Plus (1AH UA0 VGU) Mechanical 04-15-2010 HealthPro® Plus (1BB UA0 DGU) Mechanical 04-15-2010 Lasko Products® 42″ Wind Curve™   (2551, 2554) Other* 11-12-2009 G-09-102 48″ Tower Fan (4820, 4822) Other* 11-12-2009 G-09-102 Cyclonic Ceramic Heater (5840, 760000, 6000) Other* Pending** LifeWise Compact Tower Air Purifier (63-1533) Other* Pending** QuietClean Air Purifier (63-1532) Other* 06-30-2009 G-09-006 Oreck   Professional Air Purifier (AIRT, AirTB) Other* 04-22-2010 G-10-038 ProShield Air Purifier (AIR12B, AIR12GU) Other* 03-10-2010 G-10-038 Rexair, LLC Rainbow (E2 Type 12) Mechanical 02-01-2010 G-10-015 RainMate Air Freshener (AP-2) Mechanical 02-01-2010 G-10-015 Sharp® Air Purifier (FP-P30U, KC-830U) Other* 03-23-2010 G-10-036 Air Purifier (KC-850U) Other* 06-23-2010 Portable Air Conditioner (CV-P10RC) Other* Pending** SwissAir™ (IQAir North America) SolventMaster JV3 (1S0 UB0 000 / 1S0 UB0 PGT) Mechanical 04-15-2010 True Air® (Hamilton Beach) Air Decor Air Purifier (04995) Mechanical 01-06-2010 G-09-103 Direct Plug-In Odor Eliminator (04530, 04531) Mechanical 12-17-2009 G-09-103 Direct Plug-In Odor Eliminator (04530G) Mechanical 04-23-2010 Direct Plug-In Odor Eliminator (04530GM, 04531GM) Mechanical 06-07-2010 EcoClean Air Purifier (04493) Other* 07-29-2010 Pet Air Purifier (04493P) Other* 07-29-2010 Room Size Odor Eliminator (04532) Mechanical 11-23-2009 G-09-103 Room Size Odor Eliminator (04532GM) Mechanical 04-23-2010 Tower Allergen Reducer (04384) Mechanical 04-23-2010 Tower Allergen Reducer (04383) Mechanical 11-23-2009 G-09-103 UTLT+ (CCL Products Limited) Electrostatic Air Cleaner (AP-360) Other* 03-03-2010 G-10-037 Vicks (Kaz) V9070 V9071 Other* Pending**

(Source: State of California, list approved December 2009 – http://www.arb.ca.gov/research/indoor/aircleaners/certified.htm)

Sources referred to in this article:

• United States Environmental Protection Agency. “Ozone and Your Health.” http://www.airnow.gov/index.cfm?action=ozone_health.index
• — . “Ozone Generators That Are Sold as Air Cleaners.” http://www.epa.gov/iedweb00/pubs/ozonegen.html
• — . “Ozone – Good Up High, Bad Nearby.” http://www.epa.gov/oar/oaqps/gooduphigh/
• — . “Residential Air Cleaners (Second Edition): A Summary of Available Information.” http://www.epa.gov/iedweb00/pubs/residair.html
• State of California: Certified Air Cleaners http://www.arb.ca.gov/research/indoor/aircleaners/certified.htm
• Wikipedia. “Ozone.” http://en.wikipedia.org/wiki/Ozone
• — . “Ozone Layer.” http://en.wikipedia.org/wiki/Ozone_layer

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Master Resource List

We’ve put together a list of air purification and indoor air quality (IAQ) resources for use by students, researchers, academic professionals, industry experts, and media. Our list covers a variety of topics from technology to health to scientific research and will be updated regularly. Please contact us if you feel an important consumer focused resource is missing from our list. (Updated February 3, 2011)

Air Purification General

• Environmental Protection Agency (EPA): Residential Air Cleaning Devices (2nd Edition) – An August 2009 update to the EPA’s original guide to air cleaning devices in the home.  This essential document outlines common air pollutants, types of air cleaners, measuring air cleaner efficiency against common pollutants, and the health impact of air cleaners.  This document should be the starting point for any interested in the main issues surrounding residential air purification.
• Association of Home Appliance Manufacturers (AHAM): Clean Air Delivery Rate – Although a pro-industry group, AHAM has succeeded in forming an ANSI-certified standard for measuring air purifiers called the Clean Air Delivery Rate (CADR).  This site explains what the rating means for consumers and manufacturers and also lists which air purification companies participate in the program and what CADR their products received for tobacco, pollen, and smoke, the main pollutants CADR measures.
• EPA: Ozone Generators Sold As Air Cleaners – The EPA examines the health risks of ozone generating air purifiers and how ozone impacts health.
• EnergyStar Approved Air Cleaners (PDF) – Most recent list of U.S. Department of Energy “EnergyStar” rated air cleaners.  Also listed are standards used for the EnergyStar rating and a savings calculator (XLS file) for consumers to find out real savings from EnergyStar approved air cleaners.
• California Environmental Protection Agency: Particles and Air Cleaners – The State of California’s guide to air cleaner products including Fact Sheets on reducing exposure to particle pollutants, FAQ on air cleaning devices for the home, and air cleaners to avoid. 
• ______: Hazardous Ozone-Generating “Air Purifiers” – Another guide from the State of California regarding the hazardous production of ozone by some air purifiers.  Includes a list of California certified air cleaners, research reports, and press releases.
• Health Canada: Ozone Generator Q&A – Health Canada, a Canadian governmental agency, lists important questions regarding ozone generating air purifiers along with answers which including regulations, studies, consumer complaints.
• National Air Filtration Association – Trade association for the air filtration industry.  Members are individuals and companies that sell, service and manufacture air filtration products all over the world.  Membership is also extended to those who are members of other organizations like the Indoor Air Quality Association (IAQA), American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and others.
• Texas A&M: A Strategy For Reducing Pollutants In Indoor Air? – Guide detailing ways home owners can help keep indoor air clean in addition to air filtering products

Health Issues Related to Indoor Air Quality

• California EPA: Sources and Potential Health Effects of Indoor Air Pollutants – Fact sheet that identifies potential indoor air pollutants along with potential health effects
• California EPA: Reducing Your Exposure to Particle Pollutants (PDF) – Guide to identifying and limiting exposure to harmful particle pollutants, an alternative to air filtering
• California EPA: Combustion Pollutants In Your Home – How to recognize sources of indoor pollutants, health effects, and what home owners can do to eliminate these sources without air filtering
• California EPA: Combustion Pollutants In Your Home 2 (PDF – Addendum to original report) – May 1994 update to the original report that presents more current findings
• State of California Certified Air Cleaning Devices – Air cleaners that have been approved for sale by the State of California due to meeting stringent ozone requirements.
• California EPA: Cleaning Products and Indoor Air Quality – Guide to understanding how some cleaning products may contribute to indoor air pollution.
• The New England Journal of Medicine: Environmental Intervention and Asthma – NEJM study on what the impact of cleaning up the environment has on asthma sufferers.
• EPA: Will Air Cleaning Reduce Effects From Indoor Air Pollution? – Subsection of the EPA’s 2nd Edition on residential air cleaners addresses the effectivenes of these products on reducing negative health symptoms.
• WebMD: Asthma and Air Filters – WebMD opinion on the effectiveness air purifiers have on asthma symptoms.
• Asthma and Allergy Foundation: Air Filters – Discusses issues surrounding air filtration and allergy relief
• EPA/AirNow: Particle Pollution and Your Health – How particles in the air affect your health and how to manage exposure.
• How to Decide If Your Office Needs an Air Purifier – Guide to determining workplace related illness linked to poor indoor air quality and how air purifiers can help.

Air Purifier Performance

• Consumer Reports 2010 Findings (Subscription Required) – Consumer Reports releases findings on the efficiency of some air purifers about every 3 years.  Testing is based on smoke, pollen, and dust removal.  Consumer Reports does not give detailed information on their testing methodology.  Most recent air purifier test was done in their September 2010 issue (always available online) but only gave test results for 20 portable models, 2 professionally installed HVAC systems, and 5 consumer installable furnace filters.
• Consumer Reports 2007 Findings (PDF) – 2007 edition of Consumer Reports air purifier ratings made freely available to the public.
• Consumer Reports 2005 Findings (PDF) – 2005 edition of Consumer Reports air purifier ratings made freely available to the public.
• Air Purifier Clean Air Delivery Rates – Certified tests of select air purifiers and how they perform in the removal of smoke, pollen, and dust
• British Allergy Foundation: Seal of Approval (Air Purifiers) – The non-profit British Allergy Foundation has recognized select air purification products which “restrict/reduce/remove allergens from the environment of the allergy sufferer and for products which have significantly reduced allergen content.”  No guidelines are given concerning the degree to which these products restrict, reduce, or remove allergens.

Indoor Air Quality (General)

• Environmental Protection Agency: Indoor Air Quality – EPA’s main IAQ portal addressing issues like asthma, mold & moisture control, radon, education for home buyers, and an interactive tour of a home and standard indoor air quality issues home owners face.
• Indoor Air Quality Association – A non-profit organization established in 1995 that serves as an information exchange between professionals along with a public facing educational resource.  IAQA also offers certified courses from industry professionals and academic leaders in the IAQ industry.
• Occupational Health & Safety Administration (OSHA): Indoor Air Quality – Information about air quality issues in the workplace including how hazards are recognized, evaluation and control of IAQ issues, and other resources.
• Consumer Product Safety Commission (CPSC): Indoor Air Quality Publications – Safety alerts and guides to consumer products that have an affect on indoor air quality including paint strippers, biological pollutants, carpet, lead, asbestos, and much more. 
• US National Library of Medicine and National Institutes of Health: Indoor Air Pollution – A master resource list like this one covering a broad range of indoor air pollution topics from basics to organizations to important journal articles.
• Centers for Disease Control and Prevention: Indoor Environmental Quality – Lists health evaluation reports from the National Institute for Occupational Safety and Health (NIOSH) researching potential hazards in the workplace.  These reports outline how NIOSH responds to complaints and how they test and evaluate potentially contaminated areas.
• State of California Indoor Air Quality Program – The State of California has been a forerunner in addressing indoor air quality issues, especially the evaluation of air purification products.  This site lists common indoor pollutants, how to address those pollutations, and how to find an IAQ professional.
• American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE): The Indoor Air Quality Guide – Best Practices – ASHRAE advances HVAC issues through research, standards, and continuing education.  This guide addresses for building design, construction, & maintainability of IAQ systems.
• Florida Department of Health: Indoor Air Quality – State of Florida program to help educate and reduce exposure to indoor air contaminants by the general public. 

Legal Issues

• California Air Cleaner Regulation – September 2007 regulation adopted by the State of California to prohibit the sale of air cleaners that release potentially harmful amounts of ozone as part of the air purifying process.

Portable Air Purifier Manufacturers & Brands

• 3M Filtrete
• Aerus
• Air-O-Swiss
• Aireox
• Airfree
• Airgle
• Airpura
• Alen
• AllerAir
• AmairCare
• Austin Air
• Bionaire
• Biotech Research
• Blueair
• Continental Fan (CFM)
• Coway
• Dr. Caboodle
• FilterQueen
• Friedrich
• Funglan
• Germ Guardian
• Hamilton Beach
• Holmes
• Honeywell
• Ion Flow (Sharper Image)
• Ionic Pro
• IQAir
• Kenmore
• LG
• NeoAir
• NQ Industries
• Oransi
• Oreck
• Panasonic
• Pure Air Systems
• Rabbit Air
• Sharp
• Swizz Style
• Tiger Corporation
• Ultra Sun Technologies
• Vollara
• Vornado
• Westinghouse HVAC
• Whirlpool
• Winix
• Zojirushi

Industrial and Commercial Air Filtration Manufacturers

• AirFlow – Provides filtration for commercial and industrial HVAC systems.
• Cameron Great Lakes Inc. – Specializing in molecular filtration media.
• Clarcor – Product lines include air filters, antimicrobial filters, dust collection systems and filters, electrostatic air filtration, carbon filters, paint overspray filters, HEPA filters, and air pollution control systems.  Owns Airguard, Air Technologies Inc., and Purlator brands.
• Columbus Industries Inc. – Global provide of a broad range of filtration products.
• D-Mark Inc – Specializing in activated carbon filtration for odor, gas, and particulate removal.
• Flanders – Designs, manufactures, markets, and distributes air filters for commercial and residential heating, HVAC systems, semiconductor manufacturing, ultra-pure materials, chemical, biological, radiological and material processing, biotechnology, pharmaceuticals, synthetics, nuclear power and nuclear materials processing.
• Glasfloss Industries – Oldest manufacturer of HVAC filters for commercial, residential, and industrial applications.
• Koch Filter Corporation – Produces air filtration products for commercial, industrial, hospital, gas turbine, and paint filtration applications

Questions?

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Allergies and Airborne Particles

It is necessary to do some research to determine which product is best suited for the kind of allergens that cause the irritation, because not all units produce the same results.

Sources of Indoor Allergy Triggers & Effectiveness of Air Purifiers

According to the Asthma and Allergy Foundation of America (AAFA), a non-profit patient advocacy group

If these particles stay suspended in the air, some air purifiers can filter them.  However, pet dander and dust mite feces in particular are heavier particles that often settle quickly and do not stay suspended in the air for long.  Air purifiers are effective at removing tobacco smoke but the best recommendation is not to allow smoking in the house at all.

Strategies For Reducing Indoor Allergy Triggers In Addition to an Air Purifier

The United States Environmental Protection Agency (EPA) does recommend air purification products as part of the solution to tackling indoor air pollution that causes allergies, but considers it just part of a overall strategy that includes:

• Adequate ventilation
• Removal of on-going pollution sources like pets, smoke and mildew
• Replacement of materials that emit VOCs
• Air purification devices either for single rooms or whole house systems

Of course, many allergy suffers are affected seasonally by pollens and other environmental factors. In this case, the correct type of air purification device can prove very beneficial since these irritants are typically large particles that can easily be trapped by a filter.

Air Purifier Filter Technology

Air purification technology uses a number of different methods for air filtration, and it is recommended by the AAFA that you consult with your doctor to determine which type of system will eliminate the specific allergens that trigger your symptoms. AAFA cautions consumers about accepting the manufacturer’s claims and urge them to investigate the pros and cons of different methods fr themselves with their doctor’s guidence. The following air purification products are the most common for residential use:

• HEPA Filters – and must be replaced every 6 months to a year and are typcially effective for seasonal allergies. 
• Electrostatic Filters – May produce small amounts of ozone so these are rarely recommended.
• Hybrid Filters – Using barrier filters like HEPA and material such as activated carbon to filter gasses provides an effective combination to reduce some types of allergen triggers
• Ozone Generators –

For maximum protection, whole house air purification systems installed as part of the HVAC unit are highly recommended to filter larger particles combined with portable units with HEPA filtration to filter the smallest particles in rooms where allergy sufferers sleep.

Air Purifier Feature Considerations

Once you have determined the correct type of air purification system that works best for your particular allergies, you also need to consider the following factors before purchasing:

• Coverage area –
• Noise level –
• Cost and ease of filter change –
• Efficiency rating –  

For Further Information:

WebMD on Air Filters – http://www.webmd.com/asthma/guide/do-you-need-an-air-filter Allergy and Asthma Foundation of America – http://www.aafa.org/ Mayo Clinic (Asthma Friendly Products) – http://www.mayoclinic.com/health/asthma-friendly/AS00033/NSECTIONGROUP=2

 

Can an air purifier help with asthma?  Experts weigh in.

Asthma sufferers are always interested in finding new ways to remove the particles in the air that aggravate their condition, and air purifiers certainly seem like a good solution to the problem and are often recommended by doctors. However, many studies by the EPA, Indoor Air Research facilities at major universities, and the American Lung Association have shown that this is not necessarily the case, although many air purification products advertise that they are effective in reducing asthma causing airborne contaminants. While this is true to a degree, studies show that residential air purification units — especially portable ones — have a limited effect.

Independent Studies

Research reported in the New England Journal of Medicine in 2004 showed that adding an air purifier to an urban home with children who suffer from asthma did create an overall better environment, but did not totally alleviate their asthma symptoms entirely since many of the irritating factors– especially dust mites and pet dander — are stirred up by sitting on furniture, walking across carpet or laying down on a pillow, and air purifiers cannot remove them from the room until they reach the filtration mechanism.

It is recommended that the source of allergens needs to be eliminated from indoor environments before an air filter can make a substantial difference. Obvious suspects like shedding pets, outdoor dust infiltration, cigarette smoke and mold and mildew buildup must be addressed directly and it is not realistic to expect residential air purification products to thoroughly overcome such contaminants to a degree that it would eliminate the cause of asthma attacks.

Federal Testing

Environmental Protection Agency (EPA) studies have found that many of the airborne particulates that cause asthma are not filtered out because they are too small — under 0.3 microns — and that although residential air purifiers consistently decrease indoor concentrations of airborne irritants by 80%, which is an improvement, but should not be considered a definitive solution.

Ozone is Dangerous to Lung Health

The EPA actually warns consumers — especially asthma sufferers — about the dangers of air purifiers that emit ozone, claiming that short term or extended exposure to ozone can actually increase asthma symptoms because it is has toxicological properties that restrict and hamper lung function, even in healthy people. They do point out that there are no definitive studies on gas-phase filtration systems, photo catalytic oxidation cleaners (PCO) systems or UVGI (ultraviolet) systems, but express doubt that they are any more effective in reducing the tiny airborne particulates that most irritate asthma symptoms.

Medical Observations

Another important observation is discussed on the WebMD website that examines the effectiveness of indoor air cleaners. The article points out that portable room cleaners only work in the room in which they are running, so they should be located in strategic areas where the asthma sufferer spends most of the time, and especially in the bedroom at night. It recommends HEPA filters as the most effective for removing asthma causing particulates from the air, but admits that their effectiveness is limited.

Conclusion

• New England Journal of Medicine – adding an air purifier helped air quality but didn’t totally alleviate asthma symptoms due to allergens & asthma triggers still located on surfaces and not in the air

• Environmental Protection Agency – air purifiers reduced particles in the air considerably but did not filter allergy and asthma triggering particles smaller than .3 microns

• WebMD Asthma Guide – HEPA filter based air purifiers helped clean the air but effect on asthma symptoms limited

Bottom line – Air purifiers can help clear the air considerably of many (not all) asthma inducing particles and irritants but are only a partial solution for asthma sufferers.  Surfaces that contain irritants need to be cleaned regularly and sources of irritants should be removed wherever possible.

Strategies Recommended By the Environmental Protection Agency (EPA)

When the dangers associated with indoor air pollution are considered, the importance of keeping the air in your home as pure as possible becomes obvious. Fortunately, there are a few relatively easy steps that you can take which will result in a noticeable improvement in your home’s air quality.

The Environmental Protection Agency recommends a three-prong method of reducing indoor air pollution: source control, improved ventilation, and air cleaners. Let us look at each of these three methods in turn.

1 – Source Control

Sometimes the best way to deal with pollution is to cut it off at the source. Some sources are fairly easy to reduce or eliminate.

Perhaps the quintessential example of source control is cutting down on environmental tobacco smoke, also known as “second-hand smoke.” If you do not want to quit smoking, you can still decide to only smoke outside, and to ask those you live with and your guests to do the same. That way, you are not continuously inhaling the unhealthy by-products of smoking.

Here are some other methods of source control:

• Have your air tested for radon, which, after smoking, is the leading cause of lung cancer. If it turns out you have a radon problem, address it as soon as possible.

• Fight mold, mildew, and pollution-causing pests such as cockroaches and dust mites by keeping the humidity of your home low. It is also import to keep your living space clean so that it is less attractive to bugs. If you do have pests, try eliminating them using non-chemical means rather than sprays.

• Make sure that furnaces, chimneys, and other heating systems are running cleanly and efficiently.

• When cleaning, check for any warnings on the label. If it says not to use the product in an enclosed space, don’t do so. Buy only the quantities you need so that you do not have unnecessary and unhealthy chemicals sitting around your home.

• Use furniture made of solid wood, rather than pressed wood, which can release formaldehyde into the air.

2 – Improved Ventilation

Throw open the windows the next time there is good weather.

Sometimes you will need to immediately increase ventilation. We mentioned above, for instance, that it is preferable to use non-chemical means to combat household pests. However, if you do need to use insect spray, immediately open the nearest window and turn on the fan if at all possible, so that the unhealthy fumes do not stay in your house. The same goes for other chemicals, like cleaning fluids.

3 – Air Purifiers

Effectiveness of Air Cleaners

The effectiveness of air purifiers vary from model to model. Both the EPA and the USCPS say that the value of a filter should be measured based on two factors:

How much air it is capable of drawing through the filtration system.

Efficiency is usually measured as a percentage. The higher the percentage, the more unwanted material the filter pulls from the air that goes through it. The second factor, airflow rate, is measured in cubic feet per minute. This is probably the more important factor to remember, because while it is obvious that the higher the efficiency, the better, the smart buyer will consider his or her needs when it comes to airflow rate. The air volume of a room can be measured by multiplying three numbers: the length and width of the floor and the height of the ceiling.

Conclusion

Air filters, like source control and improved ventilation, are not cure-alls, nor are they an excuse to avoid taking other measures to purify the air of your home as described above. The filters used in homes are usually those that focus on removing particles from the air. Other types of filters exist, but are not nearly as common. Ozone-generating air cleaners are also available on the market, but are not recommended, as ozone itself is a health hazard. Standard particle-removing air filters are most effective against small particles. Larger particles tend to stay in the air for shorter periods of time before settling onto the floor or some other surface. They may be stirred up again by human activity, but gravity will soon pull them down once more. Therefore, air filters are less capable of ridding them from your home than smaller particles.

Please note also that air filters are currently not recommended by the EPA to control radon or its decay products, though more research is being planned in this area.

Despite these caveats, however, air filters can work wonders for indoor air quality, and can leave your home significantly cleaner than it was without one, no matter what other steps you take. Air filters are therefore an important component in improving the air quality of your house or apartment.

Sources referred to in this article:

• American Cancer Society. “Secondhand Smoke.” http://www.cancer.org/Cancer/CancerCauses/TobaccoCancer/secondhand-smoke
• United States Consumer Product Safety Commission. “Improving Air Quality in Your Home: Three Basic Strategies.” http://www.cpsc.gov/cpscpub/pubs/450.html#Improve5
• United States Environmental Protection Agency. “Improving Indoor Air Quality.” http://www.epa.gov/iaq/is-imprv.html
• —. “Indoor Air Quality.” http://www.epa.gov/iaq/is-apart.html
• —. “The Inside Story: A Guide to Indoor Air Quality.” http://www.epa.gov/iaq/pubs/insidest.html