Different Types of Air Purifiers

You’re a loving mom or dad. And you’ve decided your little angel deserves clean, crisp air in the nursery. You also know that a kid-friendly air purifier can help you clean the baby room. But which one will you buy considering the market is a sea of different types of air purifiers? In this post, I list down and describe 9 different kinds of air purifiers you need to know when shopping for a portable room air cleaner for the nursery.

Note that…

The best air purifier ever made may not be the best purifier for use in the nursery. I’ll tell you why a little further down the road.

By the way, are wondering whether air purifiers work at all? They do, the right ones at least. Read more here to learn whether air purifiers are worth it. 

9 Different Types of Home Air Purifiers

Below is a list of 6 different kinds of room air cleaners:

1. HEPA air purifiers
2. Carbon air purifiers
3. Whole-house air purifiers
4. Ozone generators
5. Ultraviolet Germicidal Irradiation air purifiers/UV air purifiers
6. Electrostatic air purifiers
7. Ionic air purifiers
8. PCO and PECO air purifiers
9. Air purifier/humidifier/dehumidifier combos

I’ll now describe each category so you can know why and when to choose each air purifier type.

1. HEPA Filter Air Purifiers

HEPA air purifiers have evolved from the early 1800s to become pretty much the gold standard in indoor air filtration. They work. At least those ones that use real HEPA filters, also known as True HEPA air purifiers. These are mechanical filters.

HEPA purifiers are the best protection you have against a whole boatload of indoor air contaminants. From mold spores, dust particles, and dust mites to pet allergens, bird dander, seasonal pollen, and other allergy triggers, HEPA filtration has you covered.

True HEPA vs HEPA-Type Air Cleaners

Here’s a SUPER important fact you should know:

Not all air purifiers that are marketed as having HEPA filters are True HEPA air cleaners.

This resource explains in detail the difference between HEPA and HEPA-type air purifiers.

Let me explain. Some clever marketers out there have learned that writing the right words sell. But in an attempt to make one more sale, they end up making all kinds of inaccurate claims. I imagine some of them know what they’re doing, and I’m here to clear the air on the never-ending HEPA vs. HEPA-type air filters confusion.

According to the US Environmental Protection Agency, HEPA indoor air cleaners remove at least 99.97% of particles with a diameter of 0.3 microns.

But wait, doesn’t that mean that these devices don’t remove particles that are smaller than 0.3 microns? No, that’s not what the EPA means. In fact, the EPA writes that portable HEPA room air cleaners tackle particles smaller than and bigger than 0.3 microns even better.

Consumer Reports agrees with this claim, saying it’s tested many HEPA air filters and learned that HEPA filters can filter out contaminants down to 0.1 microns. Now, that’s a profoundly comforting claim, one that should shove so you a little so you can stop fence-sitting and become a staunch HEPA believer.

An Air Filter May Have HEPA-like Qualities, But…

If anyone ever says in their marketing copy that their air purifier uses a HEPA-type or HEPA-like air filter, understand they’re offering something else while pretending to be promoting a real HEPA filter. HFD filters are a good example of air filters that aren’t True HEPA filters, but I keep seeing them described as HEPA-type filters.

Fact: while they may have HEPA-like characteristics, they’re not the real thing. And it’s best to assume they won’t capture a lot of the smallest particles.

Whether you’re shopping for a device to sanitize a baby room or your bedroom, choose one that offers real HEPA filtration.

Are HEPA-like filters bad? Are they ineffective? No, they’re not bad, nor are they ineffective. In fact, tests by various credible entities including Consumer Reports reveal that these units demonstrate a satisfactory filtration performance.

What HEPA filters Remove

• Pet dander
• Mold spores
• Dust mites
• Some bacteria
• Some viruses including Covid (source: Consumer Reports)
• Dust
• Seasonal pollen

What HEPA Filters Struggle to Remove

• VOCs
• Smoke
• Gaseous pollutants in general

Most HEPA purifiers also come equipped with an activated carbon filter. That means they can also remove smoke particles and even gaseous contaminants including VOCs, formaldehyde, radon, nitrogen dioxide, and sulphur dioxide to a limited extent.

2. Activated Carbon Air Purifiers

If you have a smoker in the family, please ask them to smoke outside, especially if you have young children. Because tobacco smoke particles can linger in a room’s indoor air for weeks or even months.

An air cleaner that provides activated carbon filtration is an effective way to deal with tobacco smoke particles, kitchen odors, exhaust fumes, and other VOCs.

An activated charcoal filter has many, many tiny pockets on its surface that add up to an extremely larger surface. It’s these tiny depressions that adsorb smoke particles, VOCs, radon particles, and more. Studies reveal that activated charcoal is a highly effective way to eliminate odors.

So, air purifiers remove smoke and gaseous contaminants IF they have an activated carbon filter. However, this filter isn’t the ultimate VOC remover it’s cracked up to be. Because VOCs can escape back into the air where they came from.

Plus, the tiny depressions on the surface of this filter get filled pretty fast. If you choose to smoke in your house or apartment and run a purifier to remove the smell and smoke particles, be prepared to buy tons of carbon filters over the long term.

While HEPA filters last anywhere from 6 to 12 months or even longer in some purifiers, gas and odor filters need to be replaced in about 3 months. 

Note: most activated carbon purifiers also feature a HEPA filter for capturing solid pollution.

3. Whole-House Air Purifiers

A whole-house air filtration system is precisely what the name suggests. It’s an air purification system that filters out pet dander, mold spores, pollen, and dust in the entire house rather than just one room.

A whole-house purifier works in conjunction with the HVAC system; it’s built into the HVAV system. And it filters out contaminants as they pass through in the air.

Sometimes, a whole-house system is just a simple filter mainly used to protect the components of the furnace from debris. But the air that re-enters your home is cleaner than the air that initially got into the furnace. Other times a whole-house filtration system is an electronic system that’s incorporated into your home’s ductwork. To learn more about purifiers that offer house-wide decontamination, read this post.

Whole-house systems are different than portable standalone room purifiers in that standalone units work best when used to clean one room.

If an air-cleaning mechanism doesn’t have a filter fitted somewhere in the ductwork’s airflow, it’s certainly not a whole–house system. Some manufacturers market some of the large-room models as whole-house purifiers, but that’s misleading.

No matter how large and powerful a portable room air cleaner is, it won’t be able to clean out every contaminated nook and cranny in your home.

4. Ion Generators/Ionizers/Electronic Air Purifiers

What are ionizers? Ionizers are electronic air purifiers that rely on ions rather than fans to take out pollutants, odors, and microscopic contaminants. One advantage of using an ionizer vs. a HEPA purifier is that with an ionizing unit, you’ll never ever buy replacement filters. And replacement filters can be frighteningly expensive.

How Do Ionizers Work?

Ionizers work by using electricity to form and discharge negative ions. These negative ions gravitate toward positively charged particles in the air such as pollen, dust, bacteria, smoke particles, dander, and other allergen triggers. Once the positively charged ions and negative ions from the air merge, they form denser particles that end up on different surfaces.

Some of the combined particles end up on the floor, others on countertops, draperies, baby monitors, closets, toys, baby strollers, walls, upholstery, carpeting, laptop screens, office desks, and even clothes. From there, you can remove them by cleaning up your room or house. You want to dust these surfaces as well as vacuum up carpeting and sofas.

Are Ionizing Air Purifiers Effective?

Ionizers are able to remove small particles such as smoke particles from indoor air according to the EPA. But when it comes to heavier particles such as household dust, mold, and pollen, ion generators struggle quite a bit. The same level of lameness is seen when these devices are tasked with eliminating odors and gases. Conclusion? Ion generators are better than nothing.

Are Ion Generators Safe?

Ionizers indirectly produce ozone, and ozone is a lung irritant everyone especially allergy and asthma sufferers should be concerned about. However, some ionizers are marketed as medical devices that may offer users certain health benefits.

Such medical devices are regulated by the US Food and Drug Administration, and you can assume they’re relatively safe. For purifiers claimed to have any kind of health benefits, the FDA-regulated particle concentration limit for ozone is 0.05 ppb (parts per billion).

If I experienced allergic reactions, I wouldn’t touch with a 10-foot pole any device that works by generating ozone, whether the production is direct or indirect. And of course, running an ionizer in the baby room is an extremely bad idea.

5. Electrostatic Precipitators (ESPs)

Electrostatic precipitators are electronic purifiers that work by charging particles in the air as the air streams into the unit from your room. They use electric-powered discharge electrodes to charge passing particles, giving them a positive charge or a negative charge. Once the contaminating particles are charged, a collecting plate with an opposite charge pulls these particles so the device’s owner can remove the particulate matter.

One difference between precipitators and ionizers is that the former have collection plates. But both types of air cleaners don’t rely on air filters to tackle pollution, and that’s a huge advantage.

There are two types of electrostatic precipitators namely:

• Dry ESPs
• Wet ESPs

With dry ESPs, the collected particles are removed as dry material by the application of vibrations or mechanical impulses to the collector plates. These vibrations or impulses help loosen up the buildup on the plates for an easier clean-up.

But with wet ESPs, you need to clean up the collector plates with water to rid it of the accumulated particulates. Most of the precipitators in the air purifier market are dry ESPs.

Are electrostatic precipitators effective? ESPs deliver a collection efficiency of 99 percent according to the US Environmental Protection Agency. One thing that affects the performance of these electronic appliances is particle resistivity. Performance is at its best when particles have moderate resistivity rather low resistivity or high resistivity. Read more about electrostatic precipitators.

6. Ozone Generators

Ozone generators, unlike other kinds of air purifiers whose internal mechanisms generate ozone as a byproduct, purpose generate ozone to freshen indoor air.

But how do ozone generators work? First off, ozone generators make ozone, which is essentially three oxygen atoms combined to form a larger albeit unstable molecule O_3.To generate this unstable gas, ozone generators split oxygen molecules (O₂) into their constituent oxygen atoms.

These individual oxygen atoms in turn pair up with other oxygen molecules found naturally in the air to form ozone. The International Association of Certified Indoor Air Consultants, ozone generators break down the oxygen molecule through either of two processes namely silent corona discharge and ultraviolet radiation.

Let’s see how these two processes work.

Silent Corona Discharge

Purifiers that count on this process to freshen indoor air create ozone by subjecting them to an electrical discharge. This electrical discharge causes oxygen molecules to break down into single oxygen atoms. At that point, the free-roaming atoms can and do link up with oxygen molecules to form ozone.

UV Radiation

Devices that use this method produce ozone the same way stratospheric ozone forms.

High up in the stratosphere, the sun’s UV rays initiate the disintegration of oxygen molecules (O₂) into oxygen atoms (0). These atoms then come together to form ozone.

Similarly, purifiers that rely on ozone to purify the air use UV radiation to cause the break-down of oxygen molecules into oxygen atoms which then couple up with other oxygen molecules to create ozone.

This ozone production method isn’t as efficient as silent corona discharge.

The Problem With Ozone Generators

Mold remediation contractors often use ozone generators to deodorize musty basements. And the removal process can’t be done in occupied rooms because ozone is a known lung irritant.

Ozone generators seem to make the air smell fresh, but are they really as effective as manufacturers would have you believe?

The EPA says when these machines produce ozone levels that are within acceptable public health standards, they do little to nothing when it comes to removing indoor pollution.

This source agrees with the EPA and states that ozone concentrations that stay within healthy limits aren’t adequate for proper control of indoor air pollution.

And if you’re wondering whether these room deodorizers remove mold, they don’t help with mold, even at high concentrations.

Experts even believe that ozone does nothing aside from masking odors and, worse, even messing up with your sense of smell. You’ll think you’re breathing in clean air, but that’s your impaired sense of smell deceiving you. Also, this gas can cause severe health problems at high concentrations.

I’d stay away from these kinds of purifiers if I had breathing issues in any shape or form.

7. Ultraviolet Germicidal Irradiation Air Purifiers

UV air purifiers are marketed as the ultimate annihilator of all sorts of harmful micro-organisms including bacteria, viruses, and even mold. These devices work by deactivating these airborne disease-causing pathogens. They use short-wave UV light to sterilize these micro-organisms, making them harmless. This filtration system uses a UV lamp, and this lamp needs to be replaced when the time comes, usually 12 months.

You’re unlikely to find an air purifier that exclusively relies on UV radiation. For the most part, this technology is used alongside other purification mechanisms especially HEPA. GermGuardian purifiers, for example, use HEPA filters alongside electromagnetic radiation to disinfect the air.

But are UVGI air purifiers effective? UV air cleaners don’t capture or remove air contaminants. Instead, they deactivate them. On their own, these devices can be relied on to comprehensively clean indoor air. Small wonder they’re rarely used alone.

Are UV purifiers safe? These devices produce ozone as a byproduct through a process called photolysis. But they’re not dedicated ozone generators. So, if you experience sensitivity to ozone, don’t buy anything that pushes out ozone. And if you must, make sure the unit lets you turn off the UV function when you want.

UV vs. HEPA filtration, which is better? HEPA purifiers are hands down better than UV because they actually remove contaminants from the air. What’s more HEPA filters are effective on their own while UV units often are a part of another purification system. And the best part? HEPA purifiers don’t emit ozone.

I don’t recommend UV purifiers at all. And I would never use them in the baby room/nursery.

8. PECO and PCO Air Purifiers (Combine Mechanical Filtration And Oxidation)

PECO is an acronym for Photo Electrochemical Oxidation. How does a PECO air purifier clean the air? A PECO air purifier uses a PECO filter alongside a standard prefilter to destroy contaminants in the air through oxidation and mechanical filtration. The main filter captures solid particles such as dust, smoke, and others similar to how a HEPA filter traps pollutants in its intricate web of fibers.

This prefilter serves the same role it does in HEPA filters — it filters out relatively large particles so they don’t reach the main filter. In PECO air cleaners, the prefilter does more than that, though. The prefilter makes sure that the UV light-activated nanocatalyst that coats the PECO filter gets UV light without hindrance.

A complex chemical process produces free radicals known as hydroxyl radicals. It’s these radicals that change VOCs and biologically active pollutants including viruses, bacteria, and mold into inert/safe/ harmless substances. These harmless substances are mainly water and carbon dioxide according to Molekule, a purifier manufacturer best-known for making PECO air purifiers.

Theoretically, PECO Purifies Air on the Nanoscale

Molekule Air claims that their PECO air cleaners clean the air on the nanoscale. The company claims that their sleek and pricey machines can filter out pollutants down to 0.001 microns. However, testing by Consumer Reports revealed that these claims aren’t entirely true. In fact, CR found that Molekule’s PECO purifiers were some of the poorest performers they’ve ever tested as far as particulate matter removal.

As for PCO purifiers, these clean the air through a process known as Photocatalytic Oxidation. It works similar to PECO, but it’s not as efficient and fast as PECO according to Molekule. By the way, one of Molekule’s founders contributed immensely to the development of PCO technology and later PECO. The company makes PECO and NOT PCO purifiers. Learn more about PCO here.

PECO vs HEPA filters

Molekule keeps making extremely bold claims about the unparalleled efficacy of PECO filters. They even say that PECO filters are way better than the finest air filters known — HEPA.

These assertions have created lots of buzz on the web, but are they true claims? Both Consumer Reports and NYT’s Wirecutter don’t think so. CR’s James Dickerson states that PECO purifiers could theoretically remove microscopic airborne molecules such as VOCs, formaldehyde, and odors. However, real lab testing revealed that these purifiers aren’t good at capturing relatively large airborne particles.

HEPA filters aren’t great at eating odors, smoke, and VOCs, but they’re brilliant at catching microscopic particulate matter (down to 0.1 microns) and larger particles as well. Small wonder HEPA purifiers are the most popular anywhere today.

9. Air Purifier/Humidifier/Dehumidifier Combos

Some air purifiers come as part of a 2-in-1 product designed to do more than clean the air. There are purifier/humidifier combos and purifier/dehimidifier combos.

Do air purifiers humidify air? Yes, an air purifier can moisten your indoor air if it comes with a humidifying function. When you bring together an air purifier and a humidifier, you have a hybrid mechanism that adds moisture into dry winter air while removing filthy contaminants. The Sharp KC-850U is an example of a highly rated humidifier air purifier combo.

The EPA recommends that homeowners maintain an indoor relative humidity of 30%-50%. Your RH shouldn’t surpass the 60% mark. A dehumidifier can help you remove excess moisture and keep the humidity levels down to the point where mold finds it hard to thrive in your house. The EPA even says that reducing dampness considerably can even discourage roaches and dust mites.

But do air purifiers dehumidify air? Yes, they do if they have a dehumidifying function. This kind of machine sanitizes indoor air while keeping dampness within manageable levels. It normally features a detachable tank for holding the excess moisture it pulls from the air. Once the tank fills up, it’s removed and the water poured out.

The Tenergy Sorbi Dehumidifier With A True HEPA Filter is a dehumidifier/purifier combo, and you won’t believe how affordable it is. Check out its price on Amazon. 

Final Thoughts on Air Purifier Types

The air purifier market offers multiple types of purifiers. A clear understanding of the different kinds there are will make you an informed shopper who picks up the most suitable product for their air quality situation.

Some purifiers rely on mechanical filters to physically capture contaminants. Others count on adsorption to eat odors, smoke, VOCs, and more. Usually, though, HEPA purifiers also have adsorption capabilities, and carbon filter purifiers often feature a HEPA filter.

Other options work by ionizing the air while others add ozone to change the chemical nature of unstable chemical compounds such as VOCs. Then there are whole-house purifiers that clean the air in the entire house as opposed to a single room.

PCO purifiers rely on a form of catalyst that supposedly removes and breaks down contaminants. These machines were rather slow and preceded PECO. PECO purifiers are an improved version of PCO air cleaners. As for UV purifiers, these use UV radiation to deactivate viruses, bacteria, and mode to some extent.

Don’t use any purifier that works by producing ozone or any option that pushes out ozone as a byproduct in the baby room.