Air Purifiers – A Comprehensive guide (+ we interview an expert)

Do Air Purifiers actually work | Should you buy an Air Purifier | Types of Air Purifiers | Will Air purifiers prevent corona virus | Best air purifiers | and more…
Air purifier at home
Updated: 6th May 2020
Published: 14th Mar 2020
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By Rohan Tandon

Rohan is a passionate tech journalist with a degree in English literature. He's worked as a commissi Read More...

In recent years, people have been increasingly concerned about the adverse health hazards of pollution.


There’s real cause for that concern.

According to research, breathing mildly polluted air for 10 years has the same effect on your lungs as smoking a pack of cigarettes a day for 29 years. Basically, if you live in a mildly polluted city, you’re a passive chain smoker, whether you like it or not.

In light of those growing concerns, people have turned to air purifiers to cleanse their homes, and, in turn, protect their lungs.

Air purifiers are supposed to filter out dust, smoke, pollutants, mold, and so much more, creating a fresh environment for you to breathe in. Considering the fact that indoor air can often be five times as polluted as outdoor air, the popularity of air purifiers is understandable.

But there’s also growing suspicion of the promises made by air purifiers. Skeptics believe air purifiers don’t actually offer all the benefits they claim to offer. Some believe air purifiers may clean the air of some dust, but they do nothing to reduce pollution or help those with allergies. There’s also a prevailing belief that the perceived benefits of air purifiers occur because of a placebo effect.

So what’s the truth? Can air purifiers clean all the pollution from your home? Or are air purifiers a capitalist hoax thriving on your fear of lung cancer?

What do air purifiers actually do? And do they actually work? That’s what we find out in this article.

What is an Air Purifier?

Air Purifiers are fairly self-explanatory — they’re devices that purify the air.

Air purifiers trap airborne contaminants and pollutants like dust, mold, chemicals, odors, and other toxins. However, depending on the technology, different types of air purifiers are adept at capturing different types of pollutants.

Once they trap the pollutants, they release the purified air back into your home, thus replacing the polluted air with fresh air.

How do Air Purifiers Work?

How air purifiers work

Air purifiers are made of one or several filters and a fan used for air circulation.

The fan sucks air from the atmosphere, which then moves through the filters. During this process, the filters capture the pollutants like dust mites, mold spores, etc., thereby cleaning the air. Once the air has moved through all of the filters, the fan dispels the air back into the atmosphere.

Do Air Purifiers Actually Work?

Dr. Clifford W. Bassett Author allergy expertThe expert: Dr. Clifford W. Bassett

We spoke to allergy expert Dr. Clifford W. Bassett, Founder & Medical Director at Allergy & Asthma Care of NY, Author of The New Allergy Solution, and named as one of New York’s best allergy and immunology doctors.

Here’s what he had to say about Air Purifiers:

“As an allergy and asthma specialist, I educate and advise my patients on the best options to improve indoor air quality. 

According to the US Environmental Protection Agency and CDC, “the levels of indoor air pollutants are often 2-5 times higher than outdoor levels and, in some cases, these levels can exceed 100 times that of outdoor levels of the same pollutants.” This little-known fact is particularly meaningful for the estimated hundreds of millions who suffer from asthma and/or allergies throughout the world.

So why am I taking the time to add in my thoughts about the role and benefit of using portable air purifiers? The use of air filtration is the process of removing airborne particles of varying sizes that can irritate the lungs or trigger allergic responses from the air we breathe.

The use of a portable air purifier is to improve the indoor air environment.  Some air cleaners work by trapping allergens like airborne pet dander or pollen in their physical filters, capturing particles, as air passes through them.  In fact, HEPA filters are designed to filter out at least 99.7% of particles of 0.3 microns or larger diameter. Air purifiers will generally contain a pre-filter and a HEPA filter which works to remove small particles and airborne allergens. Other purifiers work by passing air through an electrostatic filter, thus leading to particle removal.   Some will also contain carbon filter material to absorb and trap chemicals and or odors.   Certain air cleaners may produce ozone as a by-product.  It is essential that it is tested to ensure that they don’t produce harmful levels of ozone, especially for those with asthma.

Here are some helpful considerations when selecting a portable room air purifier.

  1. Select a model based on your room size and dimensions.  This will ensure the air purifier is powerful enough to clean the volume of air for a room.   
  2. Review its CADR (clean air delivery rate), which indicates the purifier’s effectiveness or ability to clean the air in a room.
  3. Look for the technical product certification 'CERTIFIED asthma & allergy friendly' air cleaners. Asthma & allergy friendly Certification Program has a whole array of CERTIFIED air cleaners that have gone through rigorous testing and are scientifically proven to meet the standards adopted by the Asthma and Allergy Foundation of America in partnership with Allergy Standards Limited. The air cleaners reduce allergens from the air and keep any ozone by-products below designated limits.  Visit

The goal now, more than ever, is to educate individuals on various interventions to improve indoor air quality which can include the use of a portable or whole-home air filtration system.”  - Clifford W. Bassett, MD, FACAAI, FAAAAI, Founder and Medical Director of Allergy & Asthma Care of New York

Should I Buy an Air Purifier?

Before you purchase an air purifier, you must understand that they’re not a one-stop solution to all of your atmospheric needs.

As mentioned above, air purifiers can remove dust, pollen, pet dander, and other forms of airborne allergens. Advanced air purifiers can also remove some smoke, radon, or VOCs. However, their ability to remove mold growth is limited, and they can’t stop radon from leaking.

As such, even though they may help by removing airborne particles, there is little scientific evidence to suggest that they can drastically improve general respiratory health.

Furthermore, you should also consider the operational and maintenance cost of air purifiers in addition to the upfront cost.

Once you’ve considered all of the aforementioned factors, you can take a call on whether it’s worth investing in an air purifier.

Here are a selection of the best air purifiers we have tested, which are also available on Amazon:

Best Overall: Blueair Classic 280i 

Best Budget: LEVOIT H13 True HEPA Filter Air Purifiers

Best for Allergies: Honeywell HPA300 True HEPA Air Purifier

Best for Large Rooms: Coway Airmega 400 Smart Air Purifier 


Will Air Purifiers Prevent Coronavirus?

Air purifiers and corona virus

As you may already be aware, COVID-19 (Coronavirus Disease) has officially been declared a global pandemic by W.H.O. Countries across the globe, such as the United States, Italy, China, South Korea, and Iran have had massive outbreaks and are scrambling to contain the situation.

In light of this situation, people are asking “will air purifiers prevent coronavirus?”

In fact, some companies have even started promoting their air purifiers as an effective protection measure against the virus. They claim their air filters can destroy or remove coronavirus from the air in a single pass.

However, these claims are completely bogus.

True HEPA filters can remove particles as small as 0.3 microns. Most viruses are smaller than 0.1 microns. Yes, some air purifiers come with UV-C lights that can destroys smaller microbes on a cellular level. However, different microbes react differently and there’s absolutely no evidence to suggest that air purifiers can destroy coronavirus.

According to Dr. Erin Sorrell, an assistant professor of microbiology in Georgetowns Center for Global Health Science and Security, “Your typical HEPA filter is not going to be able to remove coronavirus from the air. The filter itself is .3 microns and the virus itself is roughly .1 microns.”

You should also note that coronavirus is an extremely recent virus, which is why it’s still in the infancy stage of studies.

So far, the best way to prevent contamination is to follow basic practices like washing hands with soap and alcohol-based sanitizers, not touching your face, avoiding crowded spaces, and minimizing social contact.

Types of Air Purifiers

Air purifiers come with various different mechanisms and air filters. However, most modern air purifiers use HEPA filters.

The following is an overview of the various types of air purifiers and how they work.

  • HEPA Filters: These are air purifiers that use HEPA filters to capture 99.97% of all air pollutants up to .03 microns. These air purifiers use technologies that prevent bacteria and viruses from multiplying, which makes them even more effective.
  • Ozone Generators: These air purifiers are only used to trap odors, generally used in hotels that allow smoking because they can trap all the smoke odors. However, they also release a high level of ozone, which can lead to respiratory issues. As such, you need to vacate the room for about 24 hours after using the ozone generators, making them unsuitable for everyday residential use.
  • Electrostatic Precipitators: These are air purifiers in which incoming particles are charged with negative electrical energy so they can collect onto electrostatic plates. However, once the plates accumulate enough particles, they need to be replaced, increasing their maintenance costs. Furthermore, they also release ozone, which can lead to respiratory issues. While they were popular air filtration devices in the past, they’re not used anymore.
  • Ultraviolet Light Air Purifiers: These air purifiers use UV lights to penetrate the microorganism’s cell structure, permanently killing it and preventing its multiplication, As such, these air purifiers don’t trap pollutants but rather eliminate them.
  • Activated Carbon: Activated carbon doesn’t trap pollutants like bacteria, but it’s extremely effective at trapping chemicals, off-gassing, and odors. They use a highly porous form of carbon that’s heated to increase its surface area and trap the aforementioned contaminants.

As you can see, HEPA filters are some of the most convenient and advanced types of air purifiers because they trap all forms of air pollutants. They’re also easiest to maintain regularly, which is why most residential air purifiers on the market currently use HEPA filters.

However, some of the advanced air purifiers on the market use a combination of different filters, such as the activated carbon filter, HEPA filter, UV light, and even electrostatic precipitators.

What are HEPA Filters?

Hepa filter

HEPA stands for High-Efficiency Particulate Air.

As already mentioned previously, air purifiers with HEPA filters capture airborne particles of various sizes, up to .03 microns. They comprise multi-layered nets made of fine fiberglass threads that are thinner than a human hair. The filters are airtight, and the fiber strands are pleated and sealed with plastic or metallic frames.

As the fan sucks air into the purifier, the polluted air moves through the filters.

The largest air particles are captured via impaction, i.e., the particles collide against the fiber. The mid-sized air particles are captured via interception, i.e., the particles touch the fiber to get captured. The smallest air particles are captured via diffusion, i.e., they zig-zag through the various fiberglass layers until they eventually stick to the fiber.

What do Air Purifiers Filter Out?

filtering smoke, bugs, pollen, virus, dust, mold, chemicals, odors, and other toxins

Most simple air purifiers on the market capture dust mites and pollen particles, but aren’t designed to capture VOCs (volatile organic compounds) or radon. If you want an air purifier that also traps VOCs and reduced radon in the atmosphere, you’ll need one with an activated carbon filter.

And what about mold spores?

People often believe air purifiers can filter out mold spores, but that is inaccurate. Mold occurs because of the level of humidity in your home. As such, if you want to get rid of the existing mold, you should invest in a dehumidifier or humidifier to maintain optimal humidity levels in your home. That’s the only way to eliminate excessive moisture and prevent mold growth.

The following is an overview of the types of particles air purifiers can remove.

  • Allergens: These are substances that can lead to bad immune responses, leading to allergies, asthma, and other respiratory issues. Some of the most common forms of airborne allergens include pollen, dust mites, and pet dander. Air purifiers with HEPA filters can remove all of these components, thus getting rid of allergens in the atmosphere. However, they won’t necessarily get rid of allergens. For example, if there are allergens attached to your furniture, floors, or frameworks, the air purifiers wont capture them.
  • Smoke: Air purifiers have filters that can trap all of the harmful smoke particles, be it through fires or cigarette smokes. However, while they can remove most of the smoke, they won’t necessarily get rid of the smell of smoke entirely, and you may still have smoke stains on the walls and ceilings.
  • Toxins: The atmosphere in your home may also have toxins released from cleaning products and other such products. Over time, these toxins can adversely affect your health. Air purifiers can remove some of these toxins, but the best way to get rid of them is to avoid using them at all.
  • Volatile Organic Compounds (VOCs): These are harmful compounds present in the gaseous or vaporous form. They’re released from burning fuel, cigarettes, and household solvents, and they can actively lead to respiratory issues. Air purifiers with activated carbon filters can trap VOCs and purify the air.
  • Bacteria and Germs: Air purifiers with a UV light filter can also destroy bacteria, germs, viruses, and other microbes that can lead to diseases. The UV light destroys the microbes at a cellular level, thus ensuring they don’t multiply.

In summary, most household air purifiers filter airborne particles like dust, smoke, and pollen. However, if you want air purifiers that can reduce radon, gaseous pollutants, or bacteria, you’ll need advanced purifiers with activated carbon filters or UV lights.

Most Popular Uses for Air Purifiers

Remove Odors from Home

Your home may accumulate foul odors because of the combined smells from pets, mold, garbage, cooking, smoke, and other such sources.

Air purifiers generally get rid of smoke, pet dander, dust mites, and pollen, which can help remove foul odors from your home.

If your air purifier has an activated carbon filter, it can remove even more odors, keeping your home fresh.

Remove Airborne Allergens

Do you or your family members suffer from allergies?

If so, air purifiers can help you get rid of airborne allergens in the form of pollen, dust mites, and pet dander.

As these particles pass through the air purifier, they’re trapped in the HEPA filters, thus clearing out the air. Once these airborne particles are removed, your allergies may go down. However, the furniture, floorboards, and foundation in your home may also have allergens that may continue irritating you.

As such, air purifiers can only remove airborne allergens, but they can’t offer complete relief from allergies.

Reduce Asthma Inducers

Dirty air dense with dust mites and pollen can irritate your respiratory system and trigger an asthma attack.

While air purifiers won’t treat your asthma, they will reduce the number of airborne triggers in your home, offering significant relief from asthma attacks and respiratory issues.

Remove Dust Mites

No matter how well you vacuum and clean your home, you can’t get rid of all the dust mites in the atmosphere.

Air purifiers, however, suck the dirty air and get rid of all the dust mites, eventually released clean air back into your home. This can clean your air, getting rid of airborne dust mites, but it can also make your home look cleaner in general.

Prevent Germ Contamination

Some air purifiers come with technologies that trap bacteria and viruses and prevent them from multiplying. Furthermore, UV light air purifiers even kill the bacteria and viruses, eliminating them completely.

Advanced air purifiers with such UV light filters and advanced technologies can help get rid of harmful bacteria, protecting you and your family from colds and flu.

Improve Respiratory Health

By getting rid of dust mites, some airborne allergens, and asthma triggers, air purifiers can improve your entire family’s respiratory health.

Air purifiers are especially beneficial for pets because they have smaller lungs, and they spend more time closer to the floor, which has a greater abundance of pollutants.

Remove Secondhand Smoke

Air purifier filter removes smoke

Advanced air purifiers have HEPA filters that can suck all of the smoke from the atmosphere, pass them through various filters, and trap all the harmful smoke particles, before releasing fresh air.

As such, air purifiers can clean the air and minimize the hazards of secondhand smoking. However, you must find air purifiers that specifically mention they can remove smoke and odors. You should ideally get a HEPA filter air purifier with an activated carbon layer.

Improve Sleep

By removing contaminants, dust mites, allergens, and asthma triggers, air purifiers reduce factors that can make you wake up in the middle of the night. As such, they improve your sleep cycle.

Protect a Nursery and Baby

Children are extremely susceptible to respiratory ailments during the first few years of their lives. As such, the quality of air in your home is extremely important if you have a newborn baby.

With an air purifier, you can remove most (if not all) of the airborne contaminants from your home, keeping your nursery fresh for the baby.

Furthermore, if you’re concerned about the foul odors of dirty diapers, you can also set up an activated carbon filter air purifier in their room to absorb all of the odors.

All things considered, air purifiers can positively affect your baby by causing fewer allergic reactions, headaches, and respiratory ailments.

Protect the Elderly

As we get older, our respiratory systems weaken, leaving us more vulnerable to allergens, dust mites, and other airborne contaminants. As such, by getting rid of some of those pollutants, you can improve the quality of life for the elderly, helping them breathe easier.

Things to Look for When Buying an Air Purifier


Each air purifier usually comes with an indication of the size of rooms it can clean, generally indicated in square footage. For maximum efficiency, you need an air purifier that’s big enough for your room size. You should ideally get a model that’s meant for a space slightly larger than your current room so you can operate it at a lower setting and still have it be effective.

ACH Rating

ACH refers to Air Change Per Hour, which indicates the number of times the purifier can filter the entire volume of air in your room per hour. You should generally look for air purifiers with a high ACH rating, i.e., they should clean the room’s air several times in an hour. If you’re asthma or allergy sufferer, you should look for a rating of at least 4x ACH.

CADR Rating

CADR refers to Clean-Air Delivery Rating, which indicates the overall cleaning speed of an air purifier. This rating determines how fast the air purifier can remove smoke, dust, and pollen particles from your home. You should look for a CADR rating of at least 300, though you should ideally opt for CADR ratings greater than 350.

HEPA Filter Rating

You must look for True HEPA filters because they’re the best at removing airborne pollutants and particles like dust, pet dander, pollen, etc. True HEPA filters can remove at least 99.97% or all airborne particles measuring at least 0.3-micron diameter. When looking for air purifiers, you must look for ‘True HEPA’ filters — you must avoid air purifiers that market themselves as ‘HEPA-like’ or ‘HEPA-type.’

AHAM Verification

AHAM stands for the Association of Home Appliance Manufacturers, an organization that verifies and certifies the safety, effectiveness, and performance of home care devices, such as air purifiers. These standards help simplify the purchasing process, offering a guarantee of quality. As such, you must look for AHAM Verified air purifiers.

Activated Carbon Filter

As mentioned previously, an activated carbon filter is used to trap chemicals, off-gassing, and VOCs. As such, if you want to greater protection from your air purifier, you should look for one with an activated carbon filter in addition to the regular HEPA filters.

Noise Level

Most air purifiers with HEPA filters have a noise level ranging from 35dB at the lowest setting to 70dB at the higher setting. However, the exact noise level may vary for different air purifiers. You should generally look for air purifiers with a lower noise level, so you’re not interrupted while sleeping.

Energy Consumption

You should also study the air purifier’s energy consumption rating, which helps you determine the operational cost of the purifier.

Ozone Emission

Some air purifiers release ozone, which leads to respiratory issues. You should look for air purifiers that don’t lead to ozone emission and are completely safe.

Overview of the Best Air Purifiers

Best Air Purifier for Allergies/ Dust: Honeywell HPA300

Honeywell HPA300 is the best air purifier for dust and allergens. This air purifier uses a True HEPA filter, which is currently the best type of filtration system available, capable of removing up to 99.97% of all airborne particles that are as small as 0.3 microns, which makes it perfect for allergens and dust mites.

In addition to the True HEPA filter, this air purifier also contains an activated carbon filter that can absorb VOCs, smokes, gases, odors, and other large pollutants. The carbon filter is extremely effective, but it does necessitate that you change the filters at least once every three months.

This air purifier comes with three air cleaning speeds, plus a Turbo Clean setting. The Turbo Clean setting is suitable for those who want to quickly clear out the air in an extremely dirty room. For example, if you’ve been away from home for several days or weeks, you can return and use the Turbo Clean setting to get rid of all the allergens and dust quickly.

Honeywell HPA300 is suitable for large rooms measuring approximately 465 square feet. It has an extremely strong CADR and ACH rating, capable of cleaning a 465 square feet room five times in an hour.

All things considered, Honeywell HPA300 is the best air purifier for allergens and dust mite because it has a large room capacity and is equipped with a True HEPA filter and Activated Carbon filter.

Best Air Purifier for Smoke/ Pollution: Coway AP-1512HH

Coway AP-1512HH is the best air purifier for smoke and pollution. When it comes to removing smoke and pollution traces from the atmosphere, you need a powerful air purifier with advanced filtration features. This air purifier comes with four types of filters — Pre Filter, Carbon Filter, True HEPA Filter, and an Ionizer.

The True HEPA Filter removes all of the dust particles, pollen, pet dander, and other airborne particles. The Carbon Filter and Pre Filter remove odors, smoke, and gaseous pollutants. And the Ionizer creates an electrochemical response that pulls particles from the air and filters them. Between the various types of filters used, this air purifier can effectively remove all of the various pollutants and smoke from the air.

One of the greatest features here is Eco Mode, which automatically turns the fan off when no pollution is detected for 30 minutes, conserving energy. This air purifier also offers three fan speeds, timers, and an air quality indicator with which you can study the air purifier’s impact on your indoor atmosphere.

While this air purifier is extremely suitable for removing smoke and pollutants, it also gets clogged up quickly and often. As such, you may need to clean the filters once every two to four weeks.

Best Air Purifier for Asthma: RabbitAir MinusA2

RabbitAir MinusA2 is one of the best air purifiers for controlling asthma triggers in large rooms. The factor that truly sets it apart as a great purifier for people with asthma is that it comes with a True HEPA filter and six stages of air purification — Pre-Filter, Medium Filter, HEPA Filter, Customized Filter, Activated Carbon Filter, and Negative Ion Generator. As the polluted air goes through the various stages of filtration, the purifier captures all of the smallest and largest toxins, cleaning the air and ridding it of all possible asthma triggers.

In addition to the traditional True HEPA filter, this air purifier also comes with various other filters — Germ Defense Filter, Pet Allergy Filter, Toxin Absorber Filter, and Odor Remover Filter. The Germ Defense Filter removes the bacteria, viruses, and mold spores. The Pet Allergy Filter gets rid of pet dander, allergens, and other similar particles. The Toxin Absorber Filter captures and removes VOCs and other harmful gaseous emissions. And the Odor Remover Filter captures smoke, pet odors, cooking odors, and other types of smells to refresh and deodorize your room.

This air purifier can provide up to 4 air changes per hour in a 350 feet room and two air changes per hour in a 700 feet room. As such, if you have asthma, you should ideally use this air purifier if you have a medium-sized room of around 350 feet. This air purifier is also extremely quiet because it uses a BLDC motor that operates in five speeds to maintain a noise level ranging from 20.8 to 45.6 dBA.

All things considered, RabbitAir MinusA2 is the best air purifier for asthma sufferers because it has six levels of filtration plus four levels of customizable filters, making it extremely thorough.

Best Budget-Friendly Air Purifier: Germ Guardian AC4825

Germ Guardian AC4825 is a CADR 100+ air purifier meant for small or medium-sized rooms of approximately 167 square feet. This is an extremely cheap air purifier, costing less than $100, but it still offers some great filtration benefits.

This air purifier has a True HEPA Filter, which can remove up to 99.97% of all dust, pollen, and other airborne pollutants. It also has a pre-filter made of activated charcoal that reduces odors, smoke, and other large airborne particles. Finally, the UV light reduces VOCs and kills bacteria and germs, making it perfect for those who are susceptible to diseases, asthma, or respiratory ailments.

This air purifier may not be ideal for larger rooms, but it can clean small rooms four times in an hour. As such, this is one of the best and most effective air purifiers if you’re on a budget.

Maintenance of Air Purifiers - Is it worth it?

Cleaning and maintaining air purifiers

Air purifier filters may be made of paper, fiberglass, or even mesh. However, regardless of the type of filter used, they all need regular maintenance and replacement.

As such, when considering the cost of air purifiers and whether you should buy one, you also need to factor in the cost of maintenance.

The frequency with which you’ll have to change the filters depends on the amount of time you use them and the level of pollution in your home. You can also find air purifiers with reusable or washable filters, but they’re hard to maintain and not generally used in the most advanced and effective air purifiers.

You may also consider the aforementioned UV light air purifiers because they claim to destroy impurities like bacteria, viruses, and mold. However, they require a higher wattage of energy, which means they’re more expensive in the long run. Furthermore, their efficacy isn’t guaranteed because several bacteria are UV-resistant.

As such, you should ideally purchase air purifiers with HEPA filters that need to be replaced regularly. According to the Environmental Protection Agency (EPA), you should ideally replace the filters every three months for optimal functionality. In order to garner the complete benefits of air purifiers, you must also run them almost 24/7.

The operational cost of air purifiers can be approximately $50 a year, and the cost of replacing HEPA filters regularly may be approximately $100 a year. As such, after the initial purchase, you can expect to spend about $150 a year on maintenance and operation.

What are the Other Ways I Can Improve Air Quality in my Home?

Air purifiers can help you improve the air quality in your home by removing dust mites, pollutants, pollen, and other airborne particles. However, air purifiers aren’t an all-purpose method to deal with all forms of pollution.

If you really want to make a drastic improvement in your home’s air quality, you must combine the use of air purifiers with other optimal practices:

  • When your air purifiers aren’t running, you can keep your windows open to facilitate fresh air circulation. You should also open windows at opposite ends of the room to create a cross-draft and prevent locking pollutants in your home.
  • Purchase a HEPA-certified and sealed vacuum cleaner to get rid of all the dust and allergens accumulated on your furniture and floorboards.
  • You should ideally change the air filter in your air purifiers once every three months for optimal efficiency.
  • Install an exhaust fan in the kitchen, bathroom, laundry room, and other areas that deal with water. Turn the exhaust fan on whenever you’ve used these rooms, so there’s no water stagnation. You should also turn on exhaust fans while preheating ovens or cooking, so there’s no smoke accumulation.
  • Install dehumidifiers to regulate humidity in your home and prevent mold growth.
  • Stop smoking indoors and minimize the use of candles or wood fires inside your home.
  • Clean your air ducts regularly because they’re responsible for circulating air in your home, so they must be free from accumulated dust, dander, and other pollutants. You should ideally hire a professional regularly to ensure your air ducts are clean and well-maintained.
  • The fibers on rugs and carpets trap lots of pollutants and dirt, which is why they often become bedrocks of allergens. You must clean your rugs and carpets regularly to maintain the optimal air quality in your home.
  • Plants act as natural air filters. As such, you can buy some indoor plants like ferns, lilies, or palm trees to improve air quality and enhance your home’s aesthetic value.


Air purifiers, as the name suggests, purify the air. Their primary goal is to remove pollutants from the air, such as dust mites, pollen, pet dander, VOCs, bacteria, smoke, odors, and other airborne particles.

However, the effectiveness of air purifiers depends on the amount and type of filters in the purifier — some can only remove dust mites and pollen while others can also kill bacteria and germs.

In this article, we’ve given you overviews of the best air purifiers for different purposes. If you’re about to purchase an air purifier, please scrutinize your needs carefully before finding one that’s suitable for you.

FAQs about Air Purifiers

How do I know if my air purifier is working?

Air purifiers are passive devices that filter air all day long. However, this passivity also makes it difficult to determine if they’re working correctly.

The following are some of the different methods with which you can tell if your air purifier is working.

  • Filter Indicator: The best indication for whether an air purifier is working is the purifier’s internal filter indicator. The filter indicator will inform you when the air filter has reached its capacity and needs to be changed. She air purifiers even have different lights for different levels of efficiency.
  • Manual Inspection: It’s also possible for your purifier’s filter indicator to malfunction. As such, it’s a good idea to occasionally check the filter manually, especially if you believe the air purifier isn’t working at full capacity. The air filter should have enough debris to indicate it’s working, but not so much that it’s completely clogged. If your HEPA filter is too dirty and clogged, you need to get it replaced.
  • Air Quality Monitor: You can also install a separate device known as an Air Quality Monitor that informs you about the quality of air in your home. With this device, you can tell how effectively the air purifier is cleaning your home.

Where should I place my air purifier?

There are a lot of factors to consider when you’re selecting the ideal location for your air purifier. The following are some locational tips when installing your air purifier:

  • You should ideally place the air purifier in the room you spend the most time in, such as your bedroom or living room.
  • If the air purifier is in your room, it should be at least 6 to 10 feet from your bed. If it’s closer than 6 feet, you may feel a draft from the air circulation. If you place it further than 10 feet, you won’t experience the optimal benefits of clean air.
  • If you have elderly people or babies in your household, you may want to install the air purifier in the nursery, children’s room, or the elderly individual’s room.
  • Bathrooms and kitchens are also great locations to install air purifiers because they receive the highest level of pollutants.
  • If there’s a particular room in your house where smoking is allowed or encouraged, you should install the air purifier in that room.
  • If you can’t select any specific room, you can also get a complete home purifier that connects to your air ducts and cleans your entire home.
  • The ideal location for an air purifier is in the middle of the room without any objects that can obstruct the airflow. However, most people don’t want to place air purifiers in the middle of the room because they’re unattractive and can cause tripping hazards. As such, you can get 360-degree filtration purifiers and place them approximately 6 inches from the wall.
  • You may also wonder if you should place the air purifier on the floor or on a table. You should ideally place air purifiers on the floor, but that can lead to tripping hazards, especially if you have children. In that case, you can also place the air purifier on a sturdy table. You should go through your air purifier’s instruction manual to see if they offer an optimal recommendation.

Should I sleep with the air purifier all night?

Yes, you can sleep with your air purifier on all night. Since their primary function is to filter the air and clean it, you should ideally keep the air purifier turned on 24/7 for optimal air quality. Keeping the air purifier turned on at night also helps you sleep better by maintaining air quality.

Do air purifiers make the air dry?

Air purifiers don’t dry out the air. They only trap airborne pollutants and encourage fresh air circulation without affecting the moisture or humidity level. If you’re concerned about the humidity level in your home, you should invest in a humidifier or dehumidifier.

How long does it take an air purifier to clean a room?

There are a lot of factors that determine how long the air purifier will take to clean a room, such as the air purifier’s size, capacity, fan speed, CADR rating, ACH rating, and room size. However, in most cases, an air purifier can clean a room in 30 minutes to 2 hours.

How many air purifiers per room?

You only need one air purifier per room. However, you must ensure that the air purifier is rated for your room’s size. You should ideally get an air purifier with the capacity to handle a room that’s larger than yours. You must also study the CADR rating to make sure it’s capable of cleaning your room. 

Can air purifiers make you sick?

Air purifiers are ideally meant to help people with respiratory ailments and asthma. They remove airborne particles and pollutants like dust mites, pollen, pet dander, etc., which helps you breathe easier.

As such, air purifiers are designed to improve general health rather than lead to sickness. Having said that, you must still practice caution when using air purifiers. If you don’t use them correctly or use the wrong air purifier, you may aggravate your health issues.

The following are some tips on how to ensure your air purifier won’t lead to sickness:

  • Keep the air purifier turned on all day. If you turn it off, your air will quickly get polluted again, leading to allergies and respiratory issues, if you’re susceptible.
  • Some air purifiers release ozone, a gas made of three oxygen atoms. This gas is harmful and leads to throat inflammation, breathing issues, and other respiratory ailments. As such, you must avoid ozone-generating air purifiers.
  • Just because you’ve got an air purifier doesn’t mean you can stop cleaning your home. You must continue with regular household hygiene practices and clean your household furniture, floors, etc.
  • You must change your air purifier’s filters regularly. Over time, as bacteria, germs, and dirt accumulate in your air filters, they may start releasing toxins back into the environment. Furthermore, a clogged air purifier won’t clean the air effectively. As such, using a clogged air purifier can aggravate your respiratory issues even more than not using an air purifier at all.
  • When purchasing air purifiers, study their CADR rating and get a ‘True HEPA filter’ purifier. Avoid air purifiers labeled with terms like ‘HEPA-type’ or ‘HEPA-style’ because those terms don’t have a legal definition, which means they may not be effective at all.

How long does it take to notice a difference with an air purifier?

Once you’ve selected the right air purifier for your room size, you can generally notice a difference after only 30 minutes to 2 hours. In some cases, you may even notice a difference in air quality after just 20 minutes.

Do air purifiers help with smell? Do air purifiers remove smells?

The fans in air purifiers pull polluted air into filters and get rid of all dust mites, pollen, and other contaminants. As such, the air they eventually release is a lot cleaner than the air that goes in. Air purifiers with an activated carbon filter also absorb odors, smoke, and VOCs. As such, air purifiers do help get rid of odors and bad smells from your home.

Are air purifiers expensive to run?

The operational cost of air purifiers depends on the type of air purifier, type of filter, and the airflow speed.

HEPA air purifiers generally consume 50-100 watts per hour, depending on the speed. As such, if you use the air purifier for 12 hours a day, you may have an annual operational cost of $36 to $60. If you run the air purifier 24/7, you may have an annual operational cost of $72 to $120.

Do air purifiers kill germs in the air?

Most air purifiers facilitate air circulation and filter out dust mites, pollen, pet dander, and other such airborne particles. However, if you want an air purifier that also kills germs, bacteria, and viruses, you need to find an Ultraviolet Light air purifier.

UV radiation is safe for humans, but it can kill most airborne bacteria and germs, which is why it’s often used in hospitals. As such, you should get a UV air purifier that can destroy the germs and bacteria it sucks into the filter.

Are air purifiers for conditions, such as COPD?

COPD, short for Chronic Obstructive Pulmonary Disease, is a lung disease that leads to persistent cough, shortness of breath, mucus, and other such issues.

If you have COPD, or other similar respiratory or breathing ailments, then high amounts of airborne particles and pollutants can worsen your symptoms. If you live with a smoker, for example, the symptoms induced by COPD will be twice as bad. Air pollution can also lead to lung swelling and congestion problems.

Air purifiers, as we’ve already discussed, remove many of the contaminants from the air, such as dust, pollen, and debris. Some air purifiers also remove odors and smoke. As such, your immediate atmosphere places less pressure on your lungs. While air purifiers don’t treat COPD, they can help you breathe cleaner air, which can prevent the situation from deteriorating and ease some of the symptoms of the disease.

Are air purifiers good for asthma?

Air purifiers don’t treat asthma, but they can drastically minimize the recurrence of asthma attacks. Air purifiers clean the air and remove airborne allergens and dust, thereby minimizing the presence of asthma triggers. As such, if you have asthma, air purifiers will offer considerable relief.

Will air purifiers help with cigarette smoke?

High-quality HEPA filter air purifiers with activated carbon filters can capture smoke and odors. As such, air purifiers can drastically help by getting rid of secondhand smoke from the atmosphere.

Will air purifiers help with radon?

Radon is an odorless and invisible naturally-occurring radioactive gas that can lead to respiratory ailments and even lung cancer.

Air purifiers with extremely powerful carbon filters can reduce the level of radon in your home by a small margin. However, air purifiers can’t stop the radon gas from leaking. And the true efficacy of air purifiers in radon-reduction is also contested — while some sources claim air purifiers can reduce radon, others claim they can’t.

If you believe your home may have some radon, you should get a radon test kit and hire a radon specialist if the test is positive.

Author: Rohan Tandon