Aldehydes present the biggest chemical control issue in most households.
Formaldehyde, and its cousin, Acetaldehyde, are possibly the most difficult for ordinary air purifiers to handle economically and consistently.
I get sooooo many email complaints where the writer bought a new air purifier, sometimes one I recommended here.
But within maybe 90 days a deeply annoying sweet odor began to come from the carbon odor filter.
When the filter was advertised as "washable," users were unable to wash out the syrupy scent.
But, in seeming irony, leave the soiled VOC filter sit for another 90 days and the sweet odor magically disappears, only to return after another period of use.
After a decade of publishing air-purifier-power.com (and over 50 years of chemical sensitivity), I finally have some answers.
My recommended "air purifiers for formaldehyde" are posted toward the bottom of the page.
BUT air purifiers for formaldehyde and acetaldehyde removal are not cheap, and users will NOT succeed without an an effort to understand the aldehydes and their entrenchment in our lives.
AIr purifers are designed to deal with two broad classes of pollutants - particulates and VOC (volitale organic chemicals).
After common cooking, bath, and pet odors, the most common volatile organic chemical (VOC) pollutants in indoor air are airborne aldehydes.
Aldehydes, especially Acetaldehyde ("ass-sit-ul-al-de-hide"), produce a distinctively sweet odor, used in the manufacture of perfumes and so-called "air freshener" chemicals.
A sure sign of high internal aldehyde levels is when a person, drifting toward a diagnosis of MCS (Multiple Chemical Sensitivity) begins to find perfumes and colognes on both genders quite obnoxious.
Formaldehyde and Acetaldehyde are just two members of an army of naturally-ocurring aldehydes.
For example, the common food additive Vanilla is also an aldehyde.
Some alternative medical practitioners report using a Vanilla sniff reaction to test for aldehyde buildup in the body.
When I think of formaldehyde, the thing that comes to mind, right after mortuary science and Frankenstein, is animal dissection, from biology class.
I fondly recall my 1961 Junior High School biology dissection lab.
I can visualize slick black lab table tops, with frogs pinned to boards, and 13 year-olds suppressing nausea while clutching scalpels, scissors, and forceps.
I named my frog "Freddy," (Kermit The anthropomorphic Frog was years in the future).
But Freddy T. Frog was a big disappointment, all his parts were a pale white, making it difficult to distinguish organs.
Freddy was also leather tough, making him hard to cut.
Worse yet, I got a "B-" for incorrectly identifying the pancreas as a gall bladder.
Back then nobody even questioned the risks of having kids exposed to formaldehyde.
Today schools are phasing out dissection, substituting less hazardous computerized exercises using virtual models of animals.
Formaldehyde is used to preserve tissue for histology labs because it is extremely toxic to decomposer microorganisms.
Formaldehyde destroys viruses, bacteria, fungi, and parasites.
Formaldehyde also penetrates tissues and cells and crosslinks proteins.
This "fixation" is what made my Freddy's body so stiff.
Crosslinking is a biomarker for aging, causes wrinkles to form, contributes to emphysema, and is one aspect of hardening of the arteries - heart disease.
There is no safe level of human exposure to formaldehyde.
So why are hazardous aldehydes our top indoor air gas phase VOC pollutant?
Formaldehyde is everywhere, its low cost means use in many building materials and thousands of household products produce millions of exposures.
As with any toxin, the potential for abuse exists.
Marijuana has long been spiked with additives to spruce up lame batches.
Today, dipping joints in formaldehyde is the toxic addiction fad, with a music group calling themselves the "Formaldehyde Junkies."
Commercially manufactured for over 100 years, formaldehyde is a big business, with American production of 11.3 billion pounds in 1998.
Of course that kind of money means a deeply entrenched lobby.
There is even a public relations group, The Formaldehyde Council, Inc., to sing the product's praises and counter any bad news which might accidentally slip out.
Most people have heard of Formaldehyde, Acetaldehyde is less well known, but even more entrenched in our daily lives.
Maybe you have heard acetaldehyde is responsible for the "hangover" after drinking alcolhol.
But acetaldehyde is so widely prevalent, I believe it outweighs formaldehyde in scope, and in the fast decay of expensive air purifier odor filters.
European regulators have been begun to restrict aldehyde emissions and the California Air Resources Board (CARB) has taken steps toward setting indoor air standards for aldehydes.
But even CARB, well known in air purifier circles for setting purifier ozone limits when federal authorities refused to act, has only made recommendations - "...highly desirable that residential (formaldehyde) levels remain well below 27 ppb."
Meanwhile, there is no real US standard for residential formaldehyde emissions, and no product labeling requirements.
Acetaldehyde chemically quite similar to formaldehyde, and the two toxic substances are metabolized similarly by the body, using very similar molybdenum-based aldehyde dehydrogenase enzymes.
Acetaldehyde is toxic at levels of 1 part per million in the blood.
Acetaldehyde is a strong oxidant, which generates killer free radicals, consuming the body's antioxidant supplies.
Aldehydes have a strong affinity for many structures and compounds, notably the energy-producing B vitamins, especially B1 (Thiamine), B2 (Riboflavin), and Folic Acid.
The long term result is sulfhydryl depletion, which means low glutathione, our principal antioxidant and detoxifier.
Acetaldehyde slows the energy-producing citric acid cycle, interrupts nerve impulse transmission, depletes critical neurotransmitters Dopamine, Serotonin, GABA, and Acetylcholine, suppresses immunity, and inhibits hundreds of enzymes.
A phrase from my biochemistry textbook is, in my opinion, of critical importance: "Acetaldehyde inhibits the enzyme methionine synthase."
Ok, so the typical air purifier consumer doesn't share my love of old science textbooks, but many concerned with their health will have heard of "Homocysteine."
Homocysteine is the undesired end product of a stalled methylation cycle, (in which the enzyme methionine synthase plays a central part) more common every day in our brave new world.
Elevated blood levels of homocysteine are found in all the diseases of civilization, notably most cardiovascular (heart) disease, cancer, and Alzheimer’s disease.
Progressive doctors at the leading edge of research into diseases like Autism are looking for genetic defects that block the methylation cycle, I think the answer is simpler: elevated acetaldehyde.
The US Environmental Protection Agency considers formaldehyde to be a "probable human carcinogen."
There is a large body of scientific documentation describing the adverse health effects of Formaldehyde, since certain professions (morticians and embalmers, paper and pulp-mill workers, urea-formaldehyde foam workers, histology technicians, and others) offer easily studied groups.
The list of health destroying effects of aldehydes goes much further, and includes topics like addiction and cancer, but our purpose here is to emphasize the threat and assist in the selection of an air purifier, not start a medical practice.
I hope readers are convinced of the need to get these poisons out of our bodies and life space.
Elevated Acetaldehyde is found in users of alcohol, cigarettes, and consumers of carbohydrate rich diets.
Acetaldehyde is the first metabolic breakdown product of ethanol (alcohol).
But Acetaldehyde is also generated within the human body, by yeasts and other anaerobic micro-organisms.
These microbes bloom up and die off as blood sugar first spikes then falls after eating sweets and starches, many of which are aldehyde sources themselves.
Some yeasts store Acetaldehyde, releasing it when anti-yeast foods or medications are ingested.
This acetaldehyde bomb is a big contributor to the "Herxheimer Reaction," a worsening of symptoms when taking beneficial medication.
Burning anything creates both Formaldehyde and Acetaldehyde.
The principal human exposure to Acetaldehyde is car exhaust, so ubiquitous that only the most remote areas are aldehyde free.
Historically, Formaldehyde dominated emissions from gasoline engines.
But with the modern shift to grain-based ethanol-blended fuels, Acetaldehyde levels in urban air have skyrocketed.
Ethanol-burning engines emit 20 times the acetaldehyde of their straight gasoline predecessors.
One study found airborne acetaldehyde levels of up to 32 parts per billion (ppb) on Los Angeles streets.
In Brazil, which was a pioneer in the E85 ethanol-fuel switch, Acetaldehyde as high as 45 parts per billion has been measured on major urban streets, with Formaldehyde close behind.
If you are sickening, automobile exhaust, made to look acceptably "clean" by breaking down the particulates to invisibly small but deadly sizes, has the increased acetaldehyde to finish the job.
Formaldehydes have a short half-life in air, about 8 to 12 hours, where sunlight accelerates decomposition by photolitic oxidation.
So proximity to sources is the main determinant of outdoor air levels.
Continuous off-gassing indoors, where solar photolitic oxidation is absent, can result in long term elevated levels.
The good news is, although most tap water is not safe to drink due to added Fluoride, formaldehyde has a short half life in water, making water a negligible contributing source.
Formaldehyde emissions are highest when products are new, and decline over time.
Indoor exposures come from a bewildering variety of sources; building materials, indoor burning, home furnishings, household products, medicines and vaccinations, personal products and cosmetics, clothing, and food.
Wood products consume around one third of industrial formaldehyde output, with particle board/fiberboard (sawdust and chips glued together with resins) and plywood the main users.
Wood floor finishes, sheet vinyl flooring, fiberglass insulation, foam insulation, latex paint, glues, and lacquers are all sources.
Formaldehyde is heavy in many mobile homes and recreational vehicles, as demonstrated by the Hurricane Katrina FEMA relief trailer formaldehyde debacle.
Much airborne formaldehyde/acetaldehyde enters the indoor environment as a result of burning.
Air-purifier-power.com recommends immediate cessation of ALL indoor burning BEFORE installing an air purifier.
Frying at heat strong enough to blacken food or release smoke, incense, candles, fireplaces, and unvented gas stoves and water heaters should be reconsidered.
Fumes from near-house burning - leaves, idling cars, nearby woodstoves, and barbecue charcoal lighter fluid - often find their way indoors.
Kerosene space heaters are hazardous for both formaldehyde and carbon monoxide emissions.
Perhaps worst of all is the popular kitchen gas stove, a strong acetaldehyde source, and cause of many health issues.
Why do "one year" carbon air purifier filters repeatedly develop a "sweet odor" after only 100 days?
The answer is, in a majority of cases, gas burning appliances, especially the gas kitchen stove, or other persistent aldehyde emitters.
Carbon filters running where auto exhaust entering from outdoors is the main source will develop the aldehyde odor problem, but it generally takes over a year.
Carpet pads/backings, draperies, upholstery, leather (leather tanning agents), glues, dyes, wallpaper, Formica and bakelite in counter tops, furniture, and automobile interiors can outgass Formaldehyde.
Household antiseptics, germicides and fungicides, air fresheners, rug and upholstery cleaners, toilet bowl cleaners, dish-washing liquids, fabric softeners, shoe-care agents, permanent press fabrics, tanned leather goods, and car wash detergent, all may outgas aldehydes.
Formaldehyde is found in many personal products, including: perfumes and fragrances, cosmetics, shampoos, bubble baths, hair conditioners, fingernail hardener, fingernail polish remover, and antiperspirants
The problem of avoiding formaldehyde is exacerbated by the many decay reaction partial products and product names it hides under.
Here is a partial list of tell-tales;
and morbicid acid.
Removing all formaldehyde sources from the home should be the first step in reducing exposure.
If you have respiratory symptoms which worsen when you are at home, the following ideas may be useful in reducing formaldehyde and acetaldehyde exposure.
1.) Every indoor air expert will say "FIRST, remove source materials from your breathing space."
Start in the bedroom, getting rid of unnecessary clutter, moving everything even suspected of being toxic to another part of the house, to the garage is best.
No particleboard should be in the sleeping space, look under and behind furniture trim for evidence of pressed wood.
I inherited an expensive leather recliner chair, it made my living room stink of formaldehyde (no wonder he died).
Surprise your family with new electric appliances, especially a kitchen range.
2.) Increase ventilation by opening doors and windows and installing exhaust fans.
This is especially important in mobile homes, RVs, and prefabricated housing.
3.) For built in cabinets which cannot be quickly removed, seal the surfaces and edges of formaldehyde-emitting products with a non-toxic vapor barrier.
4.) After you have done the above, Install a formaldehyde-capable air purifier, especially in the bedroom.
There is little scientific evidence on the effectiveness of residential purifiers at removing airborne formaldehyde.
Scientists at National Taipei University of Technology, Taiwan, conducted a study to determine relative efficiencies of air cleaning technologies at removing Formaldehyde.
Low removal efficiencies of formaldehyde were observed by the activated-carbon air cleaner (3.3~28.6%) and the negative-ion air cleaner (18.5~30.8%).
The removal efficiencies of formaldehyde by photo-catalytic air cleaner were ranged 18.7~56.0%.
The removal efficiencies by ozone air cleaner were ranged 18.2~44.2%
Results suggested that air cleaners were inadequate to remove formaldehyde to meet WHO guidelines (0.08 ppm)."
So we MUST eliminate or at least reduce aldehyde sources if success is to be achieved.
To be effective, filter media should be replaced much more frequently than manufacturer recommended intervals.
The purchase of an air purifier should NOT considered a permanent solution to continuous formaldehyde emissions in the home.
When it comes to acetaldehyde and formaldehyde, the great majority of air purifiers, despite advertising claiming the ability to eliminate these pollutants, simply cannot do the job.
VOCs go right through paper HEPA filter media, which is designed to capture only particles.
HEPA filters catch and retain particles when they slam into a fiber, they stay stuck like a car wrapped around a telephone pole.
Odors are caused by molecules, and molecules are held to carbon odor filters by weak ionic bonds.
The visual analogy for odor retention is millions of bats hanging in a cave.
Some molecules have cave-friendly shapes, but others have an unbalanced electrical charge, these polar molecules can escape bondage more readily.
So less expensive plain carbon chem/odor filters, which hold many chems well, cannot effectively retain Formaldehyde and Acetaldehyde long term.
This is why the sweet aldehyde smell goes away when the filter is stored for a few months.
One way to get rid of aldehydes is to burn them up with oxidizers.
Ultraviolet frequencies in sunlight create reactive hydroxyl radicals, and outdoor formaldehyde is readily photo-oxidized to carbon dioxide.
But indoors there is relative darkness.
This suggests that oxidizing air cleaners might be the answer to formaldehyde.
Many premium air purifiers, such as IQAir, Austin Air, AllerAir, Aireox, E. L. Foust, and others, have added oxidant chemicals to their odor filters, with potassium permanganate the most popular.
Activated alumina, and potassium iodide are sometimes used.
So our search for air purifiers to combat Formaldehyde must eliminate all models without oxidant capabilities, either added to filter media or through active oxidants (UV, photocatalytic, plasma ionizer, and ozone).
Also, filters which combine HEPA media with odor in one-piece designs, like Austin Airs, will not be cost effective where aldehydes are a main target.
Likewise, vendors who insist on selling filters as a kit with both HEPA and odor filters in one pricey package, such as Sharp Plasmacluster, will also be dismissed.
Many ozone generators are advertised as being suitable for formaldehyde abatement.
They are not, because the source is a continuous background emission, and ozone concentrations high enough to suppress these are toxic and must be sustained to be effective.
Aldehydes are often absorbed onto surfaces and textiles, like carpets, furniture, and curtains.
These will take months to outgas, assuming the source has been removed.
But if you are living in a new mobile home, or worse, a US government FEMA trailer, and absolutely cannot escape, a high powered ozone generator rental might help.
Let it run for 72 hours while your family stays elsewhere, then air out completely.
Ozone should be reserved for desperate situations, when all else has failed and Formaldehyde and Acetaldehyde sources absolutely cannot be removed.
We cannot use an inexpensive laser particle counter as we can for particles, Formaldehyde test kits are available (see below).
So subjective odor detection or symptom relief may remain the main metrics for evaluation.
In my opinion, formaldehyde is dangerous at levels which may not provoke "allergy" symptoms or detectable smells.
Individuals chronically exposed to aldehydes may even loose the ability to smell them.
If our only method of timing the replacement of costly gas-phase filters is the return of odors or symptoms, we haven't really eliminated enough of the formaldehyde.
Prior to the leap to a costly aldehyde capable air purifier, shoppers could try testing their indoor air with a Formaldehyde test kit.
Available Formaldehyde test kits include a sampling device to expose in your space for 24 to 48 hours.
Users then mail the exposed sample collector, in a prepaid envelope, to the lab.
In about 10 days, the lab emails a .pdf document with the results in parts per million (ppm).
One amazon user review says the envelope is too flimsy, failing in the mail, and service was slow even though the lab did respond with a free replacement.
Formaldehyde test kits are available at Sylvane:
Formaldehyde Test Kit, $97, at Sylvane.com
In recent years the booming Chinese electronics industry turns out new products faster than I can keep up.
One such product is the "SM207" Formaldehyde meter, sold in the U.S. under several brand names.
I have NOT tried this product and few user reviews are available.
But it does purport to provide long-term real-time formaldehyde monitoring at about twice the price of the one-time test kit.
(TANGDA) SM207 Indoor Formaldehyde Tester at Amazon.com.
I warned you these wouldn't be low priced, we are starting with the least expensive.
Aireox D Models are designed for Formaldehyde reduction, with an electrostatic particle filter suitable for pollen and mold allergy.
Aireox is intended for buyers with Multiple Chemical Sensitivities (MCS), it is among the lowest outgassing air cleaners available.
14 amazon.com buyer reviews average a very strong 4.8 stars.
One amazon user claims to have operated an Aireox for 16 consecutive years.
Two filter options are available, one with plain activated carbon and the second with "Purafil," the Formaldehyde specialty filter.
The optional Purifil gas filter for the Aireox 45-D contains 60% activated carbon and 40% purafil and is only about @0 bucks higher than the standard filter.
Purafil is primarily the oxidant potassium permanganate.
Aireox 45 blows just 125 cubic feet of air each minute, and so is suited to very small rooms only.
The manufacturer claims four air exchanges in an hour in 240 sq. ft.
My maximum recommended room size for the Aireox 45-D is 150 sq. ft., for six air changes an hour.
However, some users report good results with new furniture, placing the Aireox air purifier near and/or on the furniture.
Low speed, of two, is user reviewed as very quiet, though there are a couple motor-developed-noise issues among the reviews.
The website www.top-air-purifier-reviews.org tested an Aireox 45D, finding low speed emitting a quiet 28 dB (decibels). The Aireox air purifier stands 14 inches high, with an 11 inch diameter.
Replacement filters are combined odor/particle, with replacements scheduled from 6 months to a year at close to $100.
Users with very high aldehyde levels will be spending about $200 annually on filters.
Maybe that's a bit higher than the insurance deductible for one visit to the doctor.
Made in the USA
very good build quality - all metal
nontoxic from the beginning
fairly quiet on both fan speeds
tight seals - no bypassing
strong customer service reputation
suited to very small areas only
half micron (.5) not a true-HEPA particle filter
filters one piece, changed often, and not that inexpensive
with "purafil' potassium permanganate and carbon, suitable for SMALL rooms or localized
source-sitting only, is $359.00 plus about $30 for shipping, at Amazon.com.
Aireox Professional Air Purifier at Amazon.com.
Photocatalytic air purifiers can actually remove aldehydes, in a manner very similar to sunshine.
Photocatalysts destroy indoor air pollutants using ultraviolet light energy bombarding a light-sensitive surface.
When energized, oxidation and reduction reactions occur on the catalyst surface, converting organic pollutants to carbon dioxide and water.
Experimental results have cast some doubt as to the completeness of the oxidation in the many hastily designed less costly PCO tack-ons now flooding the market.
Without a powerful lamp, intense UV exposure, and significant dwell time in the chamber, partially oxidized byproducts escape.
Air purifiers with PCO should be designed around the photocatalytic technology, rather than adding cheap UV and a photocat surface to an existing design.
I like the Air Oasis AO3000 as a stand alone Formaldehyde purifier.
Air Oasis 3000 $480, low ozone photocat,
no filters to buy, very long 3-year cell replacement interval.
Air Oasis AO3000 Photocatalytic Air Purifier about $480 at Amazon.com
The standard IQAir V5 odor/chemical cell has potassium permanganate, costs $100, can develop sweet odor in as little as 60 days if indoor air is heavy with Acetaldehyde and/or Formaldehyde.
I ran a V5 in my heavy auto traffic Houston apartment, the cell did pick up an acetaldehyde sweet odor, it took about 2 years.
IQAir GC Series Chemisorber ($1,299.00) air purifiers are well suited to removal of Formaldehyde.
CG Chemisorber is the lowest-priced air purifier I can truely recommend for Acetaldehyde and Formaldehyde.
A IQAir H11 HEPA-Type Pre-Filter is coupled with four filter cartridges loaded with sophisticated gas and odor control media.
H11 HEPA-Type is a European Union filter standard, roughly equivalent to the US MERV-16.
The CG Chemisorber's 32 sq ft. pre-filter retains 99% of 0.3 micron particles, just a bit shy of the 99.97% required for True-HEPAs, and 95% at a tiny 0.003 microns.
Average prefilter life is estimated at one year, replacement cost is about $80.
Note that life of the particle filter will depend on dust load factor rather than Formaldehyde and Acetaldehyde levels.
Four "Chemisorber" filter cartridges hold a total of 17 pounds of carbon with alumina/potassium permanganate media.
IQAir estimates the average Chemisorber odor filter life at 2 ½ years, assuming 10 hours run time daily and speed 3 operation.
IQAir GC Series Chemisorber Filter Cartridges, model number 102401800, cost about $375.
Not an EnergyStar, CG Chemisorber uses 215 Watts on high speed.
Boxy and heavy, ChemiSorber weighs 48 lbs., this one you won't be moving frequently.
a real air purifier for formaldehyde
quality made in Switzerland
excellent product support, never orphans an older purifier or filter
very durable product
slightly less particle focus than other IQAirs
cost to buy and operate
heavy and boxy
For those with health issues and a positive test for interior aldehydes,
please remove all the sources you possibly can, then buy an IQAir GC Chemisorber.
IQAir GC Chemisorber Air Purifier at Sylvane.com
IQAir GCX Chemisorber ($2,299) is very good at
removing formaldehyde and other VOCs.
Canadian manufacturer Airpura Industries makes filters specialized for Formaldehyde.
Airpura "F" models use activated potassium permanganate added to the carbon filter, specifically for aldehydes.
F600 models have 18 lbs. of Formaldehyde filtration media.
F600 DLX Air Purifiers have 28 lbs.
Airpura F filters are also claimed to capture ammonia (pet odor), many pesticides, benezene, and toulene.
Both F models have vacuumable pre-filters, and plenty of true-HEPA filter media to capture particles.
Airpura says the odor filters can collect Formaldehyde for up to 2 years.
This is a MAXIMUM, results WILL vary according to aldehyde levels and source strength.
Likewise, Hepa filters can last up to 5 years, assuming particle levels are reasonable.
Airpura's fan blows up to 560 CFM (cubic feet per minute)with no filters installed, but the builder claims a room size rating of 2,000 sq. ft.
This means Airpura's room size ratings are overstated.
Some users have reported air velocity much slower than 560 cfm with Airpura models.
Looking at the Airpura site, we find the F600s room size rating is based on just 2 ACH (air changes per hour).
To get closer to 6 ACH, the minimum realistic standard, I recommend Airpura air purifiers for an absolute maximum of 450 sq. ft.
But note that for chemicals slower is often better, increased "dwell time" means more complete adsorption and oxidation in the filter media.
F600 has separate HEPA and carbon filters, so users with heavy formaldehyde won't have to throw out still functional HEPAs to get fresh carbon.
Airpura F600 replacement carbon goes for about $290.
Airpuras have slower airflow for a good reason, felt (not rubber or latex) gaskets tightly seal the filter, allowing little bypassing.
F600 has no electronic controls, the motor is controlled by a variable speed dial, allowing users to compromise between filtration and noise.
Noise is a factor, decibel levels range from a quiet 28 dB on lowest speed to 62 dB on max, a bit loud.
A metal body and heavy filters make Airpuras heavy, F600 weighs 45 lbs.
Energy use is 40 Watts on Low to 120 Watts on Max.
Airpura F600 is about $850, F600DLX closer to $1,000.
Shoppers can browse the
Airpura F600 Air Purifier at Sylvane.com
Airpura F600DLX Air Purifier at Amazon.com
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