Clean Air Technology - Confusion

With so many products claiming to clean air, purifier technical evaluation is very challenging.

New products claiming technological breakthroughs are introduced with heavy marketing faster than serious reviewers can adapt.

My all time trademarked air purifier jargon favorite: “photohydroionization."

Little scientific evidence is available, and the medical establishment is skeptical about implied health benefits from using air purifiers.

Purifiers not making health claims don't fall under Food and Drug Administration jurisdiction.

Manufacturer’s competing claims concerning cleaned air provide most of the available evidence.

Deceptive marketing practices have resulted in actions by the Federal Trade Commission against some purifier manufacturers.

Affordable purifying technology is a laudable goal, but misleading marketing and variable cleaning performance have left many buyers dissatisfied.

The following links explore the technology of purifiers in detail.

HEPA Purifiers: Clean Air and Bypassing

This is the first half of my site theme, "what you can't see does hurt you."

The smallest health-robbing particulates hold the key to understanding why good purifiers cost so much.

The inside story on the HEPA filter: why does good air purification cost so much?

A quality HEPA filter will always be preceded by a good prefilter.

Many builders neglect the prefiltering stage, resulting in short, expensive filter life:

Air Purifier Pre-Filter Replacement: The Prefilter Experiments

Can a Purifier Clean Chemicals and VOC?

Here is the second half of my site theme.

I consider removal of invisible and often odorless gas phase toxins central to maintaining health.

Chemical Purifiers for Gas Phase and VOC Pollutants

Does the Ionic Purifier Cleanse Air?

The Ionic air purifier falls into two groups linked below;

1. Electrostatic precipitators like the Freidrich C90a and Sharper Image Ionic Breeze.

Electrostatic air filtration

2. Simple Ion Generators.

Ionizer Purifier: House of Blue Light

Ozone Generator: "Safe" Purifier?

Another group of machines known as Ozone Generators deliberately create ozone, loads of it, as their central clean air technology.

Ozone is a health hazard at all levels of exposure, especially to those with overt symptoms.

Ozone Air Purification: Subtle Danger

Ultraviolet Air Purifier Technologies

A time honored air purifier technology is the use of ultraviolet light to clean up microorganisms.

UV Air Purifier: The Twilight Zone

The second UV purifier technology is Phoyocatylitic Oxidation.

Photocatalytic Air Purifier: Emerging Higher Technology

Whole house purifiers, which add on to existing heating and cooling systems, are discussed next.

Whole House Air Purifier: cost effective?.

Clean and Quiet?

Noise is constant problem, with many consumers wanting quiet air purifiers that may require a technological great leap to produce.

The conventional wisdom for selecting purifiers is wrong

Virtually every authority tells you to choose air purifiers that clean only allergens and irritants which seem directly related to your symptoms.

This idea had only limited technical merit from a medical standpoint, and has been hijacked by marketers to confuse “consumers” being led to "choose" specific products.

Since the requirements of each user are considered unique, the recommended purchase is the minimum machine, in terms of price feasibility, which reduces your specific allergy.

People who only have seasonal allergies, like my wife, are supposed to need less air cleaner than those who are more sensitive, like me (MCS).

One top quality product is described as being:

“For Allergy Sufferers; Recommended for all individuals that want top of the line filtration of airborne particles, dust and allergens and who don't need gaseous chemical or odor control.”

My steadfast position:

“We ALL need to control gaseous chemicals”

Many allergy/illness causing particles are much smaller than the HEPA most-penetrating particle standard 0.3 microns.

For example, cat dander and dust mite particles can be as small as 0.1 micron, smog and cigarette smoke have particles that go down to about 0.01 microns.

Numerically, 90% of all particles are smaller than 0.3 micron.

This group of lung penetrating particles includes viruses, some bacteria, smoke, and particulate smog.

Consider the example of secondhand tobacco smoke.

When a typical inexpensive 2.0 micron HEPA-type air cleaning machine has filtered the largest (visible) particulates, room air will appear to have been cleaned.

Appearances deceive, as gas toxins and fine particulates remain.


In the chart above, note the significant health threats to the left of the red HEPA limit line.

The central theme of this site, and my entire life, is that chemicals you may not consciously perceive can destroy health.

The vast majority of less expensive air purifiers make it seem like the air is clean.

What you don’t know, and cannot see, can hurt you.

Today’s allergy can progress along a continuum toward more serious illness, so: a multistage HEPA-with-meaningful-weight-carbon series filter is, in my humble opinion, the best choice.

Some new air purifiers clean air with ozone free electronic methods, and more arrive daily, but the best still use some HEPA and carbon.

Notice that I did not say well built HEPA air purifiers without serious carbon are not cleaning air: many people will notice reduced symptoms when pollens and other large particles are gone.

A top HEPA and heavy-carbon-VOC air cleaner isn’t in everyone’s price range.

I don’t write air purifier recommendations just for wealthy folks, but please get the best air cleaner you can afford and don’t waste hard earned money on bogus or unproven air cleaner technology.

Air Purifiers at

Best Air Purifiers at

End Clean Air Purifier Technologies, try Sitemap for navigation

Last edit: 10/15/15

Before You Buy the Wrong Air Purifier

Do you need to buy an air purifier?

Got new carpets, pesticide foggers, or a “mystery smoker” in your apartment building?

Shared ventilation ducts in older construction?

Significant other just hadta have a new “clean” polyvinylchloride shower curtain?

Awwww, new kittens.....Oh boy, get ready to pay.

Vendors of every type are at your service.

I recommend caution.

With estimated sales near 4 million units sold in America last year, room air purification is a $100 million business.

If you study this industry, one thing becomes obvious: the big money is flowing through slick marketing.

While former market leader Sharper Image (Ionic Breeze) has disappeared, infomercials still sway a large percentage of buyers.

I think we could start by choosing which air purifier(s) to avoid simply by evaluating marketing tactics!

Many Choices

A search for “air purifier” produced over 800 purifiers, with a plethora of makes, models, and air cleaning technologies.

From personal air purification devices worn around the neck to multistage stacked technology behemoths, the choices confronting potential customers are overwhelming.

Searching Google yields in excess of 6 million air cleaning web sites, employing an incredible range of sales tactics.

Now I know why they say not to trust the internet!

Many legitimate air purifier sites will incorporate “consumer reports” in titles and names to imply they are someone they aren’t.

Then there are the merely incompetent “reviews”, which would be comical if the issue wasn’t so serious.

Market Penetration and Sales Volume

One big mistake I see constantly in my email is folks wanting to jump at obscure machines with artsy casings or inflated performance claims.

It takes thousands of air cleaners sold in a particular model before dealers will stock replacement filters.

When the air cleaner needs service, only then will buyers notice the obscure website they bought through is offline or has no contact info.

It doesn't take too many trips to the dumpster to make up for higher upfront costs with a quality brand and vendor.

Long-Term Air Purifying Performance

Both institutional testers (Consumer Reports and AHAM) evaluate and rank air purifiers on the basis of very brief airborne particle filtration tests.

This is very misleading to consumers.

Would you buy a new car solely on the basis of a single quarter mile drag strip performance?

"Yeah, wanna race?"

Ok, most males under 21 are excluded from the sample.

The real test for purifier air cleaning effectiveness comes long after the purchase is made.

Many builders cut costs in areas that affect long-term performance, knowing these are concealed.

Electrostatic models require careful cleaning and maintenance to maintain the same efficiency as the day of the sale.

Air purifiers with cheaper HEPA-type filters, and the majority of electronic designs, will let dirty air "bypass."

After a few months bypassing particles will coat the inside of the machine with a layer of fine dust.

Once this happens, the bargain air cleaner becomes the biggest pollutant source in the house.

I say test them under real world conditions, using actual air impurities, monitoring air filtration performance until they fail.

Quality would stick out in such tests, but don't count on seeing any real soon.

The Association of Home Appliance Manufacturers (AHAM), an industry trade group, conducts and publishes annual Clean Air Delivery Rate (CADR) tests.

AHAM also rates air purifiers by room size, helping consumers decide among models.

I use AHAM's ratings with caution, they tend to significantly overstate long term air cleaning performance.

Consumer Reports (CR) tests selected air purifiers about once annually.

Their rankings can make consumers purchase air purifiers in droves, and are therefore controversial.

I seldom agree with CR on air cleaners.

Market Consolidation

I have watched this industry grow ever since ordering my first ion generator, (it came from Sharper Image), in 1977. dylos dc1100 particle counter

A few years ago there was a surge of interest in Indoor Air Quality (IAQ).

A global flurry of activity took place from 1995 through 2003. This burst was known by consultants and engineers as the “mold rush.”

As the IAQ rush worked its way down into the residential air cleaner market, thousands of air purification products emerged worldwide.

Then came the crash of 2009, which proved the residential segment was overbuilt.

Following the shakeout, many consumers were left with unsupported products, as builders and dealers vanished.

Air purifier builders are caught, like everyone else, in the unstoppable global convergence, which will crush many small companies.

To me, this says avoid air purifiers from small or startup firms.

Staying power is important.


Low cost air cleaners are almost all made in mainland China now.

It is hard for Americans to comprehend the crisis atmosphere and extreme haste in manufacturing there.

Low end products from China have high defect rates, often colliding with the quality expectations of US consumers.

Products with the highest market share are those with marketing muscle behind them, seldom the most effective at air cleaning.

Cheaper brands can be found at discount department stores and home improvement retailers.

I was broke, had symptoms, and bought several cheap purifiers over the years.

If you are impecunious and have symptoms should you get a cheap one?

Air purifier hype aside, most ozone free air purifiers are better than nothing.

But it more cost effective to purchase quality at the outset than to risk your health with the short-average-service-life found in cheaper models.

In my opinion, the higher priced units, properly managed, can be relatively economical long term.

The trick is to keep coarse dust out of expensive filters.

Conservative companies, like industry leader IQAir, keep their products stable, using modular designs with standardized filters.

In contrast, Sharp Electronics, which made some very good purifiers, diluted their product offering with many new models, using a planned obsolescence marketing strategy.

Many consumers were frustrated and the company lost market share.

Evaluate Air Purifier Vendors

Some manufacturers sell direct, operating their own web sales.

Beyond that, there are four basic marketing channels selling air purifiers on the web;
allergy specialty stores,
supermarkets like Amazon and J&R,
electronics or vacuum cleaner outlets,
and independent distributors.

There are many knockoffs, refurbished, repaired, returned, seconds, and other questionable products at "discount" prices.

Authorized dealers generally have price supports they are required to maintain.

Lower prices or come-ons like “Call for price" or "Lowest prices" may signal questionable merchandise.

It is common to find substitution of a third party for the manufacturer in the warranty documents of products delivered at lower prices.

Many sellers make no real profits off the replacement parts, giving them little incentive to stock filters for discontinued units.

Others sell the air cleaner as a loss leader, charging sky high prices for replacement air filters.

Hidden restocking and shipping fees are often used to inflate a web bargains' price.

Online vendors are not like brick-and-mortar stores, which must maintain relationships with a local community.

Before buying at purifier sites, find out how easy it is get credit for a returned purifier, not just how easy to buy or return one.

Buy Air Purifier!

IQAir HealthPro Plus Air Purifier

At $887, IQAir HP Plus is pricey, but long term costs can be averaged down by astute owners.

The "Plus" alludes to the V5 Odor Control Cell, a strong cardboard container with five pounds of bagged charcoal and oxidizers inside.

I have owned two IQAirs, trashing one after 11 years, the other still runs 24/7.

IQAir HealthPro Plus at

Blueair 503 Air-Purifier

Atop the mid-priced bracket, the $660 Blueair 503 is a very strong particle- getter, not as good for odors/chems.

BlueAir 503 is a variant of the original 501, award winner and best seller.

With BlueAir you get pricey filter programs to retain warranty, set and forget controls, and good quality.

Warranty is collapsed to one year unless the buyer subscribes to the filter program, which ships filters every six months.

Subscriber's warranties extend as long as they keep buying filters.

BlueAir 503 can be viewed at

Blueair 503 Air-Purifier at

Honeywell 50250-S True-HEPA

How about the $127 50250-S, a 250 CADR dust grabber?

The downside is noise, a fair amount that makes sleeping on high impossible.

But 50250 is sooooo strong, I would run it as a background filter to save money on the BlueAir or IQAir replacement filters.

Honeywell 50250-S True-HEPA at

GermGuardian AC4825 Tower

$95, photocatalytic odor removal, and a True-HEPA, EPA Energy Star rated, amazing.

The downsides are filter and UV bulb costs and some noise.

There will be some fine bypassing, I recommend scotch tape at the HEPA filter's edges.

This will pay off in reduced work as the purifier fills with fine dirt and wants cleaning.

GermGuardian AC4825 Air Cleaning System with True HEPA, UV-C photocatalytic, and Odor Reduction, is a 22 inch tower, ideal for a small room (Max 125 sq. ft.) or student dorm.

A single manual rotary switch sets fan speed on one of three speeds - there is no auto mode.

A few years ago, I was skeptical about GermGuardian as they expanded into the crowded air cleaner space, but AC4825 is now a top seller at

GermGuardian AC4825 Tower at

Or see my full review:

GermGuardian AC4825 Air Purifier Review

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