Do Air Purifiers Really Work? Experts Explain What You Need to Know

Indoor air quality has become an increasingly important topic as households spend more time indoors and contend with pollutants ranging from dust and pet dander to cooking emissions and volatile organic compounds. While air purifiers are widely marketed as a solution, their effectiveness depends on factors such as filtration technology, room size compatibility, airflow capacity, and proper maintenance. Understanding these variables is essential for making an informed purchasing decision.

To provide clarity, Market.com gathered insights from scientists, medical professionals, air quality experts, and industry leaders to address the most common and important questions surrounding air purification. In the sections that follow, experts explain how air purifiers function, what CADR means in practical terms, whether they can meaningfully reduce allergy symptoms, how they compare to dehumidifiers, and which technologies are most effective against particulate matter, gases, and household pollutants.

This expert roundup offers evidence based perspectives to help readers better evaluate air purifier performance and determine the most suitable solution for their specific indoor environment.

What exactly do air purifiers do to improve indoor air quality?

Indoor air quality can change quickly due to cooking, cleaning, or outdoor pollution entering the home. Air purifiers all aim to do the same thing: clean the air from these different sources. However, how they do it, and how effective they are, can vary quite a lot.

In practice, a purifier’s effectiveness depends on how much air it can clean per hour relative to the room size, something often summarised by measures such as ‘clean air delivery rate’.

Most entry level models rely on a fan and a basic particle filter. These are effective at removing dust, pollen, and other larger airborne particles. As you move up the price range, you’ll often find higher grade HEPA filters, which capture very small particles such as PM2.5, alongside thicker activated carbon filters that remove gases from traffic pollution, cooking fumes, and everyday odours through adsorption.

More advanced units also tend to have stronger, yet quieter fans, allowing them to clean and ventilate a room faster without becoming intrusive. Many modern purifiers now include built in air quality sensors providing users with helpful data, with some models automatically adjusting their power when pollution levels rise.

Dr William Hicks is Chief Scientific Officer at Air Aware Labs

Do air purifiers actually work, and what factors determine how effective they are?

Air purifiers can be helpful, especially for people whose skin tends to react to things in the air like dust, pollen, pet hair, or pollution. From a dermatology point of view, these airborne particles can worsen skin irritation and trigger flares in conditions like eczema or generally sensitive skin. A purifier works best when it has a good-quality filter and is the right size for the room it’s being used in. It also needs to be run regularly, not just occasionally, and the filters should be cleaned weekly to keep it working properly.

That said, air purifiers are not a fix-all. They don’t remove every possible trigger and are less useful for things like strong smells or chemical fumes unless they’re designed for that. Overall, air purifiers can be a useful extra step for improving the home environment, especially for people with sensitive or easily irritated skin, but they work best alongside good skin care habits, topical treatments, and, when needed, prescription treatment with a dermatologist rather than as a single solution.

Hanna Hooper, Executive Administrator at Miami Skin Institute

How Many Air Purifiers Does a Home Need?

The answer depends on the type of air purifier you choose. Traditional portable air cleaners like HEPA or UV-based filters are designed to clean the air in a single room. If you go this route, you’ll always need one air cleaning unit per room.

A more efficient option is a whole-home, in-duct air purifier like RGF’s REME HALO. These are installed inside your HVAC air conditioning system, so just one device can purify the air throughout your entire air-conditioned space. Think of your HVAC air handler as the lungs of your house. A healthy air conditioning system is key to a healthy home.

For added protection, germicidal UV lights can be installed inside the air handler to keep the HVAC coil free of mold and bacteria, improving system efficiency and air quality.

In short:

Room purifiers = one per room
Whole-home purifiers = one per HVAC system

Installing a whole home air purifier in your air conditioning system effectively detoxifies your entire home.

Tony Julian, Chief Operating Officer at RGF Environmental Group, Inc.

Can air purifiers reduce allergy symptoms, and which allergens are they most effective against?

HEPA air purifiers are particularly helpful at reducing allergy symptoms for people with pet allergies. When you have a dog or cat in the home that you are allergic to, the dander is around the house and in the air. HEPA air filters decrease the amount of cat and dog dander in the air. HEPA filters can also help to decrease dust mite allergens.

While people with pollen allergies should generally try to keep their windows closed when the pollen counts are high, HEPA air filters can also help decrease the pollen in the air. I usually recommend HEPA filters be used in the bedroom to decrease dander and dust exposure when sleeping and optionally in other rooms where people spend a lot of time. Patients should be certain that their HEPA filter is made for the size of the room that they are using it in to make sure that it is effective.

Deborah Accetta Pedersen of Allergy & Asthma Care, PC

Are air purifiers and dehumidifiers the same, or do they serve different purposes? Additionally, how long do air purifiers typically last, and what affects their lifespan?

We tend to breathe in smoke, fine dust, particulate matter, pollution and allergens like pollen. When the room smells damp, or allergies suddenly start acting up, most of us start thinking about air purifiers. Air purifiers take the air around you, filter out the harmful particles, and send cleaner air back into your room.

However, on the other hand, a dehumidifier tackles a different problem. When there’s excess moisture in the air or develops a damp smell. That moisture also allows mold, dust mites, and microbes to thrive. If a space feels damp even after proper ventilation, a dehumidifier makes far more sense.

In many Indian homes, both air purifiers and dehumidifiers have a role to play the right choice depends on the problem you’re trying to fix, not what the product is called.

Regarding Air Purifier’s lifespan – the real determinant includes the filters and internal components, especially HEPA filters, activated carbon filters, and the motor.

Several factors influence longevity. Air quality load is the biggest one. Filters clog faster and require more frequent replacement. This is with respect to homes with high particulate matter, construction dust, traffic pollution, or pet dander. Running a purifier 24/7 naturally shortens filter life compared to intermittent use. Delayed filter changes force the motor to work harder, reducing efficiency and lifespan.

Consumers should focus less on the duration the device “lasts” and more on whether it continues to perform at certified efficiency levels. A purifier may no longer effectively remove PM2.5, allergens, or microbes.

My advice: choose models with certified HEPA filters, transparent filter-replacement timelines, and avoid models with overly exaggerated claims. An air purifier is as good as the discipline with which it’s maintained.

Ritu Sharma, PR Manager at Equinox Labs

Can air purifiers help reduce indoor air pollution caused by gas stoves or household chemicals?

Installing the right air purifier can make a big difference in reducing pollutants from gas stoves and household chemicals. Gas stoves can release harmful carbon monoxide and nitrogen dioxide, which can irritate your lungs and trigger headaches. At the same time, everyday cleaning products, paints, and new furniture release volatile organic compounds such as formaldehyde that can quietly build up and affect the air you breathe. Additionally, pollutants from outdoors can impact indoor air quality – these can range from ozone to exhaust from vehicles or generators.

Many popular air purifiers do well at capturing dust and allergens, but they’re simply not designed to handle gases and VOCs the same way, as these pollutants pass right through. Higher-end room purifiers with carbon cartridges can be effective at capturing harmful gases, but they are best suited for small spaces, and costs add up when trying to treat an entire home.

Maple Air’s Pür Plasma™ system works differently. Instead of just trapping particles like a standard filter, Pür Plasma™ creates an energized field that breaks contaminants down at the molecular level, actively neutralizing gases, VOCs, and bacteria in the air. This ozone-free, 100% organic, and chemical-free technology runs continuously and removes over 15 times more pollutants than typical systems.

The best part of our job is hearing from customers about the difference Maple Air makes in their homes. They tell us that cooking smells fade, chemical odors disappear, and the whole place just feels cleaner and fresher. If you cook on gas or use strong cleaning products, we strongly recommend installing an air purifier that neutralizes pollutants so you and your family can breathe easier whether you’re cooking, cleaning, or just relaxing together.

Andrew Ip, CEO at Maple Air

What is CADR, and how important is it when choosing an air purifier for a specific room size?

CADR (Clean Air Delivery Rate) is a standard metric that shows how much clean air an air purifier delivers per unit of time. Practically it reflects the speed at which a purifier removes particulate pollution from the air. It does not indicate filter quality, gas or VOC removal, sensor accuracy, or real-world usability.

CADR is critical when we choose a purifier for a specific room size. Too low CADR means that device works but doesn’t clean the air fast enough to make a meaningful difference. And the opposite too high indicator shows overpayment for excess capacity, energy consumption without added benefit.

Industry best practice is to size purifiers for 4-5 air changes per hour (ACH). Depending on the space size and with standard 8-foot ceilings, CADR optimal values are the following:

Small rooms (~15 m²): 100-150 CADR
Medium rooms (~30 m²): 200-300 CADR
Large rooms (~50 m²): 350-450 CADR

What is most important while choosing a purifier is to test a smoke CADR – the most demanding value that represents the smallest particle’s level in the air. A purifier that performs well on smoke will generally perform well on dust and pollen.

For consumers, CADR should be treated as a baseline sizing metric, evaluated alongside HEPA grade, carbon filtration, noise levels, and control intelligence. But it doesn’t indicate the completeness of air quality.

Anton Kolotov, Air Quality Expert at ATMO Technologies