Do Air Purifiers Work?

Many families these days — those who can breathe without issues and those who face a bit of difficulty — are investing money in air purifiers. In 2020, the world’s air purifier market crossed the $10 Billion mark according to imarc. As for the U.S. air purifier market, it expanded by a staggering 57 percent per Verify Market’s data. And some of these air-purifying mechanisms can be prohibitively pricey. But, do air purifiers work?

Do air purifiers actually kill pet dander, viruses, dust mites, mold spores, and bacteria as well as remove wildfire smoke, TVOCs (Total Volatile Organic Compounds)?

In this post, I answer these questions and many others you might be asking at this point.

What’s An Air Purifier?

An air purifier is a device or machine or system designed to purify air. There are outdoor air filtration systems and indoor purifiers, but standalone air cleaners for indoor use are more common. The main job of an air purifier is to capture or remove a whole bunch of air contaminants from polluted indoor air.

Did you know that the air you breathe inside of your home might be dirtier than the seemingly more polluted air outside? According to the Environmental Protection Agency, the air indoors is significantly more contaminated than the air outdoors. That’s a sobering thought, one that’s nudged many in the direction of air various kinds of air filtration systems.

A Brief History of Air Purifiers

The history of air purifiers can be traced back to the 18th century thanks to the coal-driven industrial revolution. Now, the industrial revolution pumped out tons of air pollution. As the problem grew, a solution to counteract this worrying development was deemed necessary.

Here’s what the timeline to today’s super-efficient portable air cleaners looks like:

1823: Charles Deane Thinks the Smoke Helmet and Patents It

Then the British inventor, Charles Anthony Deane, happened. Deane developed in his nimble mind a piece of equipment that firefighters could use in smoke-filled situations. And he patented the so-called Smoke Helmet in 1823.

Dean’s nascent air purification system was a copper helmet into which a blast of fresh air was to be pumped using a pair of bellows. A flexible collar and leather garment were attached to the helmet, and a short pipe allowed the air the wearer breathed out to escape.

1827: Augustus Christian Siebe Builds Deane’s Smoke Helmet

Dean would later sell his patent to Edward Bernard, his employer. Later, through the contribution of a German-British engineer called Augustus Christian Siebe, Dean’s Smoke Helmet became a reality.

Unfortunately, the invention didn’t see much adoption and that was the end of the road for it as an air purifier. The equipment was later converted into a kind of diving helmet.

1854: The First Fully-functional Respirator Materializes

Then John Stenhouse showed up and built the first-ever practical respirator in 1854. Stenhouse reasoned that wood charcoal could increase the effectiveness of air purification systems. And he developed a charcoal-based fireman respirator.

1940: HEPA Gets Invented

Fast-forward to the second year of the Second World War (1940), and the first HEPA air filter came onto the scene. This filter shielded scientists from radioactive particles as they worked in nuclear research labs.

1963: The Hermes Brothers Sell the First-ever Residential Air Purifier

But it wasn’t until 1963 that the Hammes brothers in Germany made the first-ever residential air filtration system for residential use.

The Hammes brothers (Manfred Hammes and Klaus Hammes) marketed their product through a company called Incen Air Corporation which later birthed the well-known IQAir.

1998: IQAir Makes Super-compact Air Cleaners

In 1998, IQAir gave families highly compact portable air cleaners, and these machines have been getting better and more efficient over the years.

The modern high-end air purifier cleans air faster and features all kinds of bells and whistles including a PM2.5 sensor, auto mode, and even Alexa integration.


Do Air Purifiers Actually Work?

Research documenting solid air purifier benefits seems to be scarce, but some studies suggest that using efficient air filters reduces allergens and Particulate Matter (PM). Also, the British Thoracic Society’s guideline on asthma management recommends using air filters to tackle pet allergens and other kinds of allergens.

And according to Healthline, air cleaners may reduce the source of asthma and allergy symptoms. Healthline further states that continually using air filters might have sufferers experiencing reduced asthma symptoms and allergic reactions. Please consult a qualified physician about how you can improve your symptoms.

That being said, an air purifier is far from being the panacea of ALL indoor quality issues. While it’s a good idea to use these air cleaning mechanisms, it’s important to understand what they’re good for and where they struggle a bit or don’t work at all. You want to couple your indoor air filtration efforts with other effective strategies for better results.

How Does An Air Purifier Work?

Different versions of air purifiers work differently, but each air purifier type works by drawing in dirty air through an inlet vent using a mechanical fan or other mechanisms such as convection. The machine then captures, removes, or neutralizes allergens, toxins, and particulates from the air. Some types may collect air contaminants on a plate from where it’s then cleaned out. Finally, the device belches clean air outward through an intelligently placed air outlet.

For most air purifiers, the fresh air outlet is on the top of the device or on one of the sides. As for whole-house air filtration systems, these are essentially MERV-rated air filters paired up with the HVAC system. Using a whole-house purifier together with portable air-cleaning devices achieves much better results than just using either purifier type.

How an air purifier works and how effective it is depends on what type of filtration media it employs.  HEPA, UV-light, and ionizing air purifiers work differently. But some models feature a mix of two or more filtration technologies. For example, a True HEPA air purifier may also offer UV filtration and activated carbon filtration.

Some Air Purifiers Work By Filtering Out Pollutants

HEPA air purifiers trap air particles when they bombard the web-like barrier with force. Particles such as mold spores, dust, some viruses, some bacteria, pet dander, and pollen get trapped.

Once too many of these particles accumulate on the fibrous filter, they clog it up, and that’s when the filtration should be replaced.

Some HEPA air purifiers have odor-removing capabilities thanks to an additional filter called an activated carbon filter for odors, VOCs, and smoke particles.

Others Work By Ionizing the Air

Other air purifiers work by neutralizing particulates without actually filtering the contaminants out. Another filtration mechanism is where an air emits or releases negative ions.

These negative ions gravitate toward positive ions in the air such as allergens and particulates, neutralizing them. The neutralized particles then drop to the floor and you can easily vacuum them off.

Some Purifiers Nuke Viruses and Bacteria Through UV-C Light

Finally, there’s a group of purifiers that kill microorganisms including viruses and bacteria using UV-C light. A good example is GermGuardian air purifiers, venerated germ killers.

But don’t use UV air purifiers in the baby room — they give off ozone. Ionizers are another type of air purifier you shouldn’t put to work in your baby room.

What Pollutants Do Air Purifiers Catch?

HEPA air purifiers are good at catching solid pollutants (particulate matter) such as pet dander, dust, seasonal pollen, mold spores, dust mites, bacteria, and viruses. Devices with a True HEPA filter theoretically remove 99.97% of particles with a diameter of 0.3 microns.

When set to the top fan speed, these machines have proved themselves able to trap microscopic indoor air pollutants as small as 0.1 microns according to Consumer Reports.

CR further states that HEPA air purifiers can even tackle Covid-19 particles. The diameter of these viral particles sits in the 0.1-0.5 micron range. Since HEPA air purifiers can remove 0.1-micron particles, they should be able to battle Covid-19 particles.

CR recommends that families with a member fighting off you–know-what-I-mean invest in a good HEPA-based device. According to CR, this is the best protection the rest of the family can hope for against these lethal viruses.

HEPA air purifiers also remove wildfire smoke particles and secondhand tobacco smoke particles. Wildfire smoke particles have a diameter of 0.1-0.7 microns. And since good HEPA filter-reliant air cleaners can easily 0.1-micron particulates, they can as well remove smoke from the ravaging wildfires homeowners in fire-prone California and other places see from time to time.

That’s why the EPA recommends the use of True HEPA air purifiers for removing wildfire smoke particles.

Do Air Purifiers ONLY Remove 99.97% of 0.3-micron Particles?

Many manufacturers state their HEPA purifiers as being able to remove 99.9% of 0.3 microns. But that doesn’t mean this air sanitization gear can’t capture particles that are smaller than 0.3 microns. According to the EPA, 0.3-micron particulates are the most penetrating particles, and they’re the most challenging to filter out.

The EPA further authoritatively asserts that HEPA purifiers can remove bigger or smaller than 0.3-micron particles with greater efficiency. Don’t believe a thing I say about the efficacy of air purifier filters. Instead, read what both the EPA and Consumer Reports say about those rather bold claims.

What Air Contaminants Won’t Air Purifiers Remove?

HEPA-like purifiers, sometimes marketed as the real deal, aren’t capable of filtering out the smallest particles. These devices won’t, for example, effectively deal with virus particles since many of them are only good for larger particles (over 2 microns).

Do HEPA air purifiers remove VOCs? The simple answer is NO, UNLESS the air purifier also offers activated carbon filtration. A purifier with an activated carbon filter should be able to adsorb VOC particles. Charcoal filters have numerous pores on the surface, and during adsorption, VOC and gaseous pollutants pack in these tiny pores.

The trouble with activated filters as far as eliminating VOCs is that these ultra-small holes on the surface of the carbon media clog up with pollution soon. At that point, the media isn’t able to adsorb any more VOCs.

Another problem is that the effectiveness of the carbon filtration process varies with the indoor environment. If your room heats up like when you turn on heating, the VOCs can turn back into gaseous form and escape back into the room.

Conclusion: Air purifiers with activated charcoal can and do remove VOCs. However, they’re not as excellent at removing and holding VOCs such as paint fumes, kitchen fumes, and VOCs from various cleaning products. For that reason, the best way to remove VOCs is to remove the source of VOCs or store them sealed up nice and tight.

How Do I Know If My Air Purifier is Working?

One way to know if an air purifier is working is to place a hand over the clean air outlet. If the airflow is weak or inconsistent, that device certainly isn’t working well. Another way to check if an air purifier is working is to listen to it. If you can’t hear any sound, chances are it stopped working or wasn’t working from the beginning.

Are Air Purifiers Worth It?

Yes, if your indoor air quality is bad and you want to move to a much better place. Also, if you or your baby are dealing with allergic reactions to chemicals such as VOCs and allergens such as pet dander and dog dander, using an air purifier may have various limited benefits.

While these are strictly NOT medical devices and shouldn’t be thought of as such, they can eliminate substantially what triggers those allergic reactions. But you don’t need to have breathing issues to spend some money on a device that sanitizes the air, especially in these post-Covid times.

Factors Affecting the Effectiveness of An Air Purifier

  1. Type of filters inside
  2. Quality of air filters
  3. Where you have placed the air purifier
  4. How well you maintain the filtration system
  5. How powerful the air purifier is for your room
  6. The condition of the machine

Type and Quality of Filtration Media

A device with a medical-grade HEPA filter and an activated carbon filter will likely outperform one without a HEPA filter and charcoal filter. And one with a UV light would out-compete other options in terms of killing germs.

Where You Place the Air Purifier

Where you’ve placed your air purifier in the baby room, bedroom, living room, or basement matters, too. The best place to stand a purifier is where there’s enough clearance on all sides for unhindered entry of dirty air and exit of fresh, pristine air after purification.

How Well You Care for the Purifier

And if you resolve to replace your filters when the manufacturer says you should, you’ll likely see better performance than someone who waits forever before filter replacement. Where a manufacturer says you can clean the filter, clean the filter as frequently as advised.

How Efficient the Device is (Its CADR Rating)

A machine with greater air filtration efficiency will definitely outperform a unit that limps in the efficiency department. A purifier with a CADR rating of 300 will clean a room three times faster than one with a CADR of 100. Since air purifiers aren’t typically run on the highest setting, buy a unit that’s rated for bigger rooms than you wish to decontaminate.

For example, if you’re buying for an air purifier for a small baby room that measures 150 sq. ft., consider buying a unit designed for 180 or even 200 sq. ft. Avoid buying something that’ll be overkill for the space you’re sanitizing.

Condition of the Air Purifier

Declining performance happens with baby strollers, car seats, bikes, and most other adult and baby gear. You can expect the effectiveness of your bedroom or nursery air purifier to dwindle with time. I have noticed this phenomenon myself. A purifier I bought for my kiddie’s nursery worked like a dream when it was brand new. But in the third year, I did notice it didn’t have the vigor of the good old days.

Types of Air Purifiers

  • HEPA air purifiers: They rely on HEPA filters that remove 99.97% of 0.3-micron pollutants.
  • Ultraviolet Germicidal Irradiation/UV purifiers: They use ultraviolet rays to nuke bacteria, mold, and bacteria.
  • Activated carbon purifiers: Uses an activated charcoal filter to remove VOCs, smoke, fumes, and vapors.
  • Electrostatic precipitators: Ionize the air by generating negative ions through corona discharge. These ions attract positively charged contaminants, and the combo particles collect on a plate from where they’re finally removed.
  • Ionic air purifiers: Also known as ionizers, ionic air purifiers work just like electrostatic purifiers. The difference is that the particles end up on the floor instead of on a plate. With this purifier, you want to vacuum your house a lot.
  • Ozone generators: These are supposedly the finest deodorizers/odor eliminators. They work by neutralizing household smells and VOCs by releasing ozone into the room. According to the International Association of Certified Home Inspectors, ozone is unstable. Ozone’s third oxygen atom attaches itself to unstable organic compounds (VOCs), changing their chemical structure. This alteration supposedly makes the affected compound less dangerous or turns it into a less harmless irritant.
  • Whole-house purifiers: Part of the heating system

Don’t Use Ozone Generators, Ionizers, or UV Air Purifiers in the Baby Room

Using an ionic, UV, or electrostatic air purifier in the baby room is a VERY bad idea. According to the EPA, even healthy people can end up with respiratory symptoms after breathing in ozone for even short durations of time. Long-term exposure to ozone can worsen asthma symptoms and might be one of many contributors to asthma development. The EPA further states that children are at a significantly higher risk compared to adults.

Pros and Cons of Air Purifiers

Let’s dive right in.


  • Air purifiers improve indoor air quality by removing harmful impurities.
  • They remove pet allergens, and that might reduce the frequency of allergic reactions.
  • Studies that the US EPA has seen show that portable air cleaners may improve SOME allergy and asthma symptoms. Note that it’s NOT major improvements and NOT ALL symptoms.
  • Fewer bacteria and viruses in indoor air might mean you’ll fall sick less often.
  • Some purifiers can remove tobacco smoke particles, and these particles are known carcinogens.
  • They can help reduce radon particles to a limited extent. *A purifier isn’t the recommended strategy to reduce your home’s radon gas pollution levels. Contact your local state radon control office and see if they can recommend a radon removal service provider.
  • You’re likely to enjoy better sleep with a good purifier whirring away in your bedroom because there are fewer triggers.
  • Options with an activated carbon filter can adsorb odors including cooking odors, smoke smell, and tobacco or MJ odors.


  • Air Purifiers and replacement air filters can be expensive.
  • Some options aren’t worth the money, because they don’t do a thing for your room.
  • Some air purifiers can be noisy.
  • You usually need more than one.
  • Your energy bill will see a spike.
  • Purifiers don’t remove ALL pollutants.

5 Misconceptions and Half-Truths About Air Purifiers

Below are a few half-truths and misconceptions about the effectiveness and benefits of portable air cleaners that you should be aware of:

  1. Air Purifiers eat odors, wildfire smoke, VOCs, and even radon gas extremely well.
  2. Purifiers are a kind of medical device.
  3. ALL HEPA Air Purifiers are great at particle removal.
  4. Air Cleaners capture ALL bacteria, viruses, and mold.
  5. Room cleaners eliminate the need to sweep or clean up.

Let’s take a closer look at these misconceptions people have about purifiers. 

While air purifiers with activated carbon filters may remove VOCs, radon, smoke, and odors, that’s not what they do best. Particulate matter removal is where these devices really shine.

And no, these aren’t medical devices and aren’t meant to replace meds. I suggest you talk to a pulmonologist or allergist before you stop taking those meds. That said, these household appliances offer a bunch of benefits that could make your life more comfortable.

HEPA purifiers capture bacteria and viruses, but certain types of these microorganisms are too small that removing them can be hard. And while home air cleaners with Ultraviolet Germicidal Irradiation kill viruses and bacteria, they’re not super effective according to the EPA.

With UVGI cleaners for home use, mold, viruses, and bacteria aren’t exposed to enough UV radiation. Even though UVGI purifiers are marketed as dedicated and focused killers of bacteria, viruses, and mold, HEPA cleaners are a much better bet.

A Quick Air Purifier Guide

Are you looking to buy a baby room air purifier or a unit to sanitize your bedroom, family room, office, or basement? Here’s a detailed baby air purifier buying guide.

Below are a few things you should watch out for:

Air Changes Per Hour (ACH)

Lots of people and even marketers don’t seem to understand that a purifier’s ACH isn’t a fixed or specific number.

The number of air circulations a unit pumps out depends on the room’s size. Manufacturers sometimes say, “This air purifier has an ACH of 5” without telling parents and other consumers what room size the stated ACH was tested for.

A unit that circulates air in a 200 sq. ft. room 4 times will manage only 2 air circulations in a 400 sq. ft. room.

Clean Air Delivery Rate (CADR)

CADR measures how efficient a given air purifier model is, and it can help you to easily compare two similar choices. An air purifier model gets its CADR rating from AHAM Verified, a third-party entity that tests air purifiers for manufacturers.

No federal agency formulates or regulates CADR rating standards, and some companies such as Dyson and a few others aren’t even interested in this metric.

Without knowing the CADR number of a baby room purifier, you’ll have to rely on the purification coverage information the manufacturer provides.

Ideally, you should buy a purifier whose CADR is at least 2/3 of the room you’re cleaning. If the room’s square footage is 465 sq. ft., the unit should have a CADR of 310, give or take.

For better air cleaning efficiency, buy a unit built for sanitizing and deodorizing larger rooms. Why? It’s because AHAM runs submitted devices on the highest rating. And you don’t want to run your machine on the highest fan speed in a space where silence is gold such as the bedroom or baby room.

Air Filtration Technology in Use

Does the purifier use HEPA, carbon, PCO, PECO, UV, ionization, or ozone generation to clean the air? Whenever unsure of what to choose, choose a HEPA purifier with odor removal capabilities.

Purifier Material

Obviously, you want a sturdy purifier that won’t tip over easily if pushed by small, busy hands or paws. No one wants a flimsy purifier that shatters into smithereens if it falls over. When buying online, sturdiness may not be easy to assess. So, ready honest reviews before buying.

Amount of Power Gobbled Up

Some purifiers are power consumption monsters. Look for an Energy-Star rated air purifier. A unit with the Energy Star rating consumes electricity with great economy while filtering out pollutants efficiently.

Price Considerations

For the most part, pricier purifiers are made using better quality materials that last longer. Also, they tend to offer high-quality air filters that translate into comprehensive cleaning.

Depending on the size of the baby room or whichever room you want to clean, put aside a spend of anywhere in the $100-$300 range.

I’ve seen really good options in the $100 price range. A good example is Levoit’s Core300, an ozone-free option. But if you want all the bells and whistles, go for a $500-$1000 unit.


Brand doesn’t matter that much when buying a purifier for the nursery or for any other space. But you must pay attention to the device’s safety credentials. UVGI room cleaners, ionizers, and ozone generators are a no-no in the baby room. Levoit, Honeywell, Medify, and many other air purifier brands have models that don’t spew out ozone.

Look for These Features

Keep a keen eye on the futures below when shopping for a portable room allergen remover:

Night Mode/Sleep Mode

Nothing is better than being able to dim a unit bright blue light when it’s time to hit the sack. I once owned one where I had to cover the LED display with a cloth so I could sleep in peace.

Filter Replacement Reminder

Usually, this is a timed reminder based on how long the manufacturer wants you to use your room purifier before chucking the filters out. The average purifier’s HEPA filters retain acceptable performance for about 6 months. Prefilters typically last between 3 and 6 months. When the period ends, the indicator light turns on. Pull out the filter in question and check whether it’s too filthy. If it’s not too dirty and it still seems to do the job, shake it a bit and put it back in.

Set It and Forget Mode (Auto Mode)

The auto mode isn’t an absolute necessity. It’s a nice-to-have feature. The auto mode quickens or slows the fan speed depending on the signal it gets from the inbuilt air quality sensor.

If the sensor thinks the air is clean, it sets the device to the lowest mode. That way, your machine runs when the air is dirty and sleeps when it’s clean, saving energy and reducing noise.

Built-in air quality sensors aren’t always accurate. In fact, many tend to give inaccurate indoor pollution readings when compared to external air quality monitors.

Additionally, the auto mode can fail anytime. I like devices that let me choose the manual mode any time I want. You probably don’t need the auto mode, especially if this fancy feature bumps up the unit’s price.


Some options have a programmable timer that lets you set up the duration of time you want your unit to run. It can be a 2,4,8-hour timer or any other interval the manufacturer chooses. This feature saves energy. It’s like the auto mode, except there’s no inbuilt air quality sensor.

Air Quality Sensor/Monitor

Some units have PM2.5 and PM10 air quality sensors that display indoor quality levels using real numbers or colors. This feature may not always work reliably, and it may not even be accurate. And it almost always drives the unit cost up. You probably don’t need it.

Top Tips on How to Help Your Air Purifier Clean Air

Here’s a list of things you can do alongside running an air purifier in a baby room or wherever:

  • Vacuum your baby’s room and every other room with a HEPA vacuum once each week.
  • Dust solid surfaces such as tables, countertops, walls, flooring, and other surfaces regularly.
  • Ban smoking in your home.
  • Use environmental-friendly cleaning products. Stay away from harsh chemicals that release harmful fumes and vapors.
  • Use a dehumidifier or other strategies to keep humidity low to discourage mildew and mold growth. Low humidity also prevents dust mites from thriving.
  • Replace filters in your air purifier or HVAVC system regularly as per the filter maker’s recommendation. For most HEPA filters, replacement happens at month 6 while HVAC air filters last anywhere between 30-90 days/1-3 months.
  • Remove carpeting if your allergies get too severe (source).
  • Wash your bedding at least once each week in hot water (source).
  • Give your pets (dogs, cats) a bath from time to time to reduce animal dander in your house.

Are Air Purifiers Worth the Money? Final Thoughts

So, air purifiers work, especially those that provide both HEPA and activated carbon filtration. These portable room air cleaners remove solid particles (PM2.5 and PM10) extremely well. But while they also remove contaminants such as viruses, bacteria, radon, VOCs, and other gaseous pollutants, they don’t post excellent performance in this area.

Since air purifiers actually reduce pet allergens and other allergy triggers suspended in indoor air, they can be a useful purchase for those who need them.

If the air in your home crawls with pet dander, bacteria, viruses, pollen, dust, dust mites, and other particles, a HEPA purifier could be a worthwhile investment. But they certainly have their limitations.

Never place an air cleaner or any other device that generates ozone in the nursery/baby room.

Author: Esther Moni

I'm Esther Moni, a proud stay-at-home mom and a psychology graduate of the United States International University (USIU) . I hate it when anyone calls me a housewife, because what does housewife even mean? Being a mother of two babies and a pup, Bailey, as well as being Ricky's wife tires me to no end, but I still manage a smile at the end of it all. And when my boys aren't done doing mischief, I juggle writing a post on parenting or baby gear performance for this blog and running my little counselling office based out in Nairobi. <a href="">Visit my Facebook profile here</a>, and this is my <a href="">LinkedIn profile</a>, and here's my <a href="">nascent youtube channel.

Esther Moni

I'm Esther Moni, a proud stay-at-home mom and a psychology graduate of the United States International University (USIU) . I hate it when anyone calls me a housewife, because what does housewife even mean? Being a mother of two babies and a pup, Bailey, as well as being a wife tires me to no end, but I still manage a smile at the end of it all. And when my boys aren't done doing mischief, I juggle writing a post on parenting or baby gear performance for this blog and running my little counselling office based out in Nairobi. Visit my Facebook profile here, and this is my LinkedIn profile, and here's my nascent youtube channel.