Do air purifiers work? Air purifier myths and facts debunked

The home air purifier market has undergone many shifts and starts in its decades-long history as an affordable solution for indoor air quality. Along with those shifts have been seemingly groundbreaking advancements in filtration technologies that may seem like the next revolution in air purification.

But not all air purifiers safely clean the air.

Not all air purifiers safely clean the air.

Let's take an evidence-based approach to the industry and separate the fact from the fiction.

What should I look for in an air purifier?

Before we examine the various air purifiers on the market with a critical eye, it’s essential to have a solid understanding of what does make a good air purifier.

Air purifier comparison chart

1. HEPA filters are the standard for the industry.

What is a HEPA filter?

High-efficiency particulate air (HEPA) filters capture airborne particles from moving air using a dense, random arrangement of fibers. HEPA filters use the physics of particles moving through air to yank them out of the air flow. Their operation is simple but extremely effective, and HEPA filters are now standard issue for almost every air purifier on the market.

But it wasn’t always that way.

Air purifiers have been around for well over a century. The first air purification systems appeared in the 1850s in charcoal-based masks used by coal miners. They were designed to keep toxic dust out of their lungs. The technology was so successful that, less than twenty years later, respirators were added to these types of masks to protect firefighters from breathing in smoke chemicals and pollutants (1).

Beginning in the 1940s, the United States Atomic Energy Commission started experimenting with high-efficiency particulate arrestance, better known now as HEPA, as a method of shielding soldiers from atomic radiation on World War II battlefields (2).

HEPA filters did nothing to filter radiation particles, but researchers quickly learned that HEPA filters could filter out many harmful pollutants.

In 1963, Manfred and Klaus Hammes, the founders of IQAir, introduced the world’s first residential air filter based on HEPA technology, helping reduce indoor pollution as well as chronic asthma symptoms. Not long after, HEPA became so widespread that the U.S. Department of Energy (DOE) required that all filters sold under the name “HEPA” must filter at least 99.97% of airborne particles down to 0.3 microns (3).

Since then, HEPA air purification has become the standard for the air purification industry. HEPA is now thrown around as a generic term for air filters, but HEPA filters continue to filter 99.97% of particles down to 0.3 microns.

The HyperHEPA filter builds upon the HEPA model to create even more efficient filtration systems.

Many manufacturers, including IQAir, have built upon the HEPA model to create even more efficient filtration systems. IQAir’s patented HyperHEPAfilter is one such filter. HyperHEPA filters remove 99.5% of particles down to 0.003 microns, which are 100 times smaller than the DOE’s required 0.3-micron particle size.

2. Not all air purifier designs are created equal.

All air purifier manufacturers know that their filters need to live up to this HEPA standard. But long-standing, strict guidelines around air filters can provide a false sense of security in HEPA.

To advertise an air purifier as HEPA, it only needs to contain HEPA paper, the paper used to construct a HEPA filter. Whether the air purifier’s Total System Efficiency meets HEPA requirements is another story. In fact, most HEPA air purifiers are not tested for total efficiency (4).

The hidden factor at work here is leakage. Despite the high efficiency of many HEPA filters, the housing designs of many air purifiers are not airtight. This means that dirty, unfiltered air passes around the HEPA filter through tiny openings, cracks, and space around the frame of the HEPA filter itself or between the frame and the purifier housing (5).

So even though many air purifiers claim that their HEPA filters remove nearly 100% of particles from the air that passes through them, they’re only telling part of the story. In some cases, the actual efficiency of the whole air purifier design, with leakage considered, is closer to 80% or less (6).

Even though many air purifiers claim that their HEPA filters remove nearly 100% of particles from the air that passes through them, the actual efficiency of the whole air purifier design, with leakage considered, is closer to 80% or less.

Some air purifier manufacturers have resolved this issue with designs that are built to minimize or eliminate leakage. IQAir uses patented 3D UltraSeal knife-edge-in-groove sealing between the filter frame and the purifier housing to guarantee the full efficiency of our HyperHEPA filtration media.

3. Concerned about gas and odors? Go beyond HEPA.

While HyperHEPA filters are great at getting particles out of the air, they do NOT take gases and odors out of the air.

Unlike particles, the molecules that comprise gases, odors, and volatile organic compounds (VOCs) are not solid and will float through even the densest HyperHEPA filters. That’s where activated carbon filters come in.

How do these filters work? It’s simpler than you might think:

  1. Chunks of carbon material (like charcoal) are exposed to high concentrations of oxygen.
  2. Countless pores open on the carbon surface, increasing the carbon surface area enormously. At this point, a pound of activated carbon can have the same surface area as 100 football fields.
  3. Several pounds of activated carbon are arranged in a flat “bed” and packaged in a proprietary filter design (such as IQAir’s V5 Cell gas and odor control filter).
  4. Air passes through the activated carbon bed.
  5. Gas, chemical, and VOC molecules are adsorbed into the carbon pores, meaning that they chemically bond to the extensive charcoal surface area.

Activated carbon adsorption is the go-to method of filtration for gases as well as chemical pollutants from vehicle emissions and combustion processes (7)(8).

Activated carbon adsorption is the go-to method of filtration for gases as well as chemical pollutants from vehicle emissions and combustion processes.

Some air purifiers are designed to maximize activated carbon in case you’re more concerned about, for example, gases from cooking or odors from pets than about particle pollution in your home. IQAir’s GC MultiGas is built for such a purpose—while carbon filters generally use a few pounds of carbon, the GC MultiGas contains 12 pounds of activated carbon as well as impregnated alumina, providing well over 1200 football fields worth of surface area for gas and VOC molecules to adsorb to.

The takeaway

Now you know that the elements of a good air purifier are:

  • HyperHEPA media for particle filtration
  • No system leakage due to sealed filter and purifier housing
  • Activated carbon for gas and odor filtration

But we're not done yet. Just as important to know is what not to look for in an air purifier.

What should I avoid in an air purifier?

When considering air purifiers, some people wonder about their effectiveness and even potential risks. Question often arise, such as "Do air purifiers work?" or "Are air purifiers effective?" The answer is that while some air cleaning methods can remove particles and pollutants from the air, their capabilities are often limited.

But it's not just about effectiveness. People also ask, "Are air purifiers bad for you?" This concern arises from potential hidden costs to your health. It's important to be aware of inefficiencies and any potential risks associated with the air purifier you're considering before making a purchase.

So, if you're in the market for an air purifier, remember to ask yourself whether it will be effective at removing pollutants and particles from the air, and whether it poses any risks to your health.

Ionizer air purifiers

Ionizers are purported to purify air by sending out negatively charged ions (anions) that attract positively charged pollution particles (cations), causing them to leave the air and stick to surfaces like ceilings, walls, and furniture.

Many popular air purifiers use ionization technology, also called negative ionization, as a central component of their operation. Research suggests that ionizers can help stop potentially infectious molds and bacteria from spreading in sterile environments like dental clinics and hospitals (9)(10).

But there are two critical downsides to ionization (11)(12):

  • Ionizer air purifiersdon’t get rid of pollutants. Particles charged by negative ions aren’t removed from the air—they merely stick to surfaces nearby. This includes surfaces inside your airways, such as your windpipe and alveoli, the sacs of air in your lungs. Pollutant build-up can cause heart, lung, and other respiratory conditions.
  • Ionizer air purifierscan generate harmful ozone. Ionizers produce ozone (O3) that can build up to dangerous levels indoors. At even low levels, indoor ozone can irritate your airways, trigger asthma attacks, damage your olfactory bulb (the organ that helps your brain process odors), and even be fatal at high concentrations.
Indoor ozone can irritate your airways, trigger asthma attacks, damage your olfactory bulb, and even be fatal at high concentrations.


Don't buy an ionizer air purifier.They don’t remove particles from the air, and the ozone they produce can have harmful side effects, even if the purifier claims that they only charge the particles “a little bit.”

Ozone Generators

It’s worth saying again: ozone is TERRIBLE for you, especially indoor ozone build-up. The health concerns are serious enough that in 2017, California banned the use of ozonehome air purifiers (13).

Ozone generators use a process called corona discharge to release ozone molecules into the air. When an ozone molecule intermingles with a particle or gas molecule, an ozone atom clings to the other molecule and blows it up in a process known as oxidation. Oxidation in the atmosphere after a lightning strike is also what makes theair smell so distinct after a thunderstorm.

However, ozone generators do little to clean air and are quite bad for you. Here’s just a short (and far from complete) list of reasons why (14)(15)(16)(17)(18):

  • Ozone can take years to fully clear even a small room of gases.
  • Ozone reactions can introduce ultrafine particles (UFPs) into the air.UFPs can get into your lungs and your bloodstream, causing heart disease and even stunting lung development in children.
  • Indoor ozone levels can rise five to ten times above recommended limits,which range from 0.05 to 0.1 parts per million (ppm), because of a lack of ventilation and in combination with outdoor ozone that seeps indoors.To put this in perspective, those who are sensitive to ozone, such as children, people with asthma, and pets, start experiencing health effects at only 0.01 ppm. Even a “safe” ozone generator that emits a small amount of ozone can quickly trigger potentially life-threatening ailments like asthma attacks.


Don’t buy an ozone generator. They’re NOT air purifiers. Not only do they fail to clean your air, they hurt you and the most vulnerable in your home: your children and your pets.

UV Light Purifiers

Ultraviolet (UV) light is often used to disinfect equipment in hospitals and prevent the spread of harmful strains of bacteria and viruses (19)(20).

One of the most common UV purification methods is called ultraviolet germicidal irradiation, or UVGI.

In UVGI, intense UV lights are shined on bacteria and viruses, damaging their DNA beyond repair. Bacterial cells and viruses then shut themselves down because they can no longer function. This is called apoptosis, or programmed cell death, which effectively destroys their ability to cause infections (21).

But UV air purification isn’t all it’s cracked up to be. Here’s why(22) (23) (24) (25) (26):

  • Bacteria and viruses need to be exposed to UV light for a certain amount of timebefore they’re rendered harmless: some strains need to be treated with UV for several hours in direct UV light before they’re destroyed.Home UV air purifiers don’t shine UV light on them long enough to be genuinely useful.
  • Some bacteria can come back to life and become infectious again even after being disinfected by UV light.
  • UV lights do nothing for pollutant particles.Air treated with UV light can still be full of harmful particulate matter, like PM10 and PM2.5.
  • Many UV air purifiers produce ozone.
  • UV light can burn your skin and damage your eyes. Sure, most UV purifiers block the light from shining out of the purifier, but even brief UV exposure can cause permanent skin and eye damage as well as cancer.
Air treated with UV light can still be full of harmful particulate matter.


Don’t buy a UV light air purifier. UV light somewhat disinfects but doesn’t purify air, and research shows that UV’s disinfection potential for air may be exaggerated.

What do I do now?

At this point, you should feel like you have a good sense of what’s fact and what’s fiction when it comes to a truly effective air purification system.

So, what should you do now, armed with your knowledge of what makes a good air purifier? You have a multitude of options for maximizing your indoor air quality:

  • Get a HyperHEPA air purifier. Patented HyperHEPA filtration technology removes 99.5% of pollutant particles down to 0.003 microns, the smallest particles in existence.
  • Use advanced gas-phase filtration.
    • Patented V5 Cell gas and odor control filters, used in HealthPro Series air purifiers, eliminateharmful chemicals and compounds with five pounds of activated carbon.
    • The GC MultiGas features 12 pounds of activated carbon and impregnated alumina to help protect you against indoor gases and chemicals, in addition to our powerful HyperHEPA particle filtration.
  • Use a personal air purifier. Atem Series personal air purifiers are equipped with HyperHEPA filtration technology and a PureJet diffuser that instantly blankets you in clean air. They’re sleek, compact, and portable, allowing you to breathe virtually pure air anytime, anywhere.
  • Install a whole-house air purifier. Your heating, ventilation, and air conditioning (HVAC) system at home uses outdoor air to heat and cool your home, so even with an indoor air purifier, your air still might become polluted by outdoor particulates on days with poor air quality. The PerfectPro Serieswhole-house air purifier is equipped with the most powerful HyperHEPA filters available for a residential air purification systems. It fits seamlessly into your existing HVAC system, ensuring that air entering your home is always up to the highest possible standard of quality.

Still not sure? Read about some of the misconceptions that surround air purification technology. Use our Help Me Choose tool to see what air purifier may work best for your indoor air quality needs.

The most capable air purification technology is always backed by evidence-based facts and science. When it comes to choosing the best air purifier, science has got your back.

The number one air cleaning solution for your home.

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