Do Air Purifiers Really Work?
There’s the million dollar question that everyone wants answered! But before we get to that, you need to understand HOW air purifiers work:
- Dirty air is pulled into the purifier by the fan built into an intake grill.
- Dirty air passes through various filters, which remove pollutants, dust, allergens, and contaminants.
- Filtered air is expelled via another fan and distributed into the room.
Pretty simply process, right?
The effectiveness of the air purifier is determined by the types of filters used (see Types of Air Purifiers below), but most purifiers can effectively deal with dust, smoke, and pollen—all larger particles that can easily be trapped by the filters. On the other hand, volatile organic compounds (VOCs), which come from gaseous pollutants, paints, adhesives, and cleaning products, are not removed from the air.
IMPORTANT NOTE: Air purifiers use filters to remove particles and pollutants. If you don’t change the filters regularly—every 3-6 months—the purifiers won’t work properly to filter the air.
Do Air Purifiers Get Rid of Odors?
Some air purifiers are able to eliminate odors—pet odors, fumes, cigar/cigarette smoke, etc. However, the basic, standard purifiers aren’t designed to deal with odors.
You see, the basic purifiers are made using High Efficiency Particulate Arrestance (HEPA) filters, which are designed to eliminate pollen, allergens, dust, and contaminants in the air. Odor particles, however, are not trapped by the HEPA filters. If your purifier has only an HEPA filter with no additional filtration systems built in, it may help to reduce odors, but it won’t eliminate them altogether.
To deal with odors, you need special additional filters designed to neutralize the odor particles. Activated Carbon Filters are the most commonly-used filters for dealing with odors, as the odor particles are adsorbed by (or bond with) the charcoal particles and are neutralized.
Do Air Purifiers Help With Dust Mite Allergy and other Allergies?
A lot of air purifiers are touted as appliances to help you deal with allergies—pollen, dust, pet dander, and so on.
The highest-grade HEPA filters are able to filter out up to 99.99% of airborne particles (including allergens) down to 0.3 microns, which means they’re highly effective at eliminating the things that could be triggering your allergies.
That being said, air purifiers will only work to remove allergens from the air if there is no other way for allergens to get into your home. For example, if you have pets at home, the purifiers can only eliminate so much dander before your pet sheds all over again. If you have a window open, the pollen will float inside and contaminate your air. If you have a home filled with dust, no amount of filtration will clean the air because you’ll kick up more dust every time you step or sit. An air purifier will work in enclosed spaces, but it’s up to you to prevent more allergens from entering your home.
As for dust mites, remember that purifiers can only deal with particles floating in the air. Dust mites do not remain airborne, but they build up on your bed, pillows, sheets, furniture, and carpets. Because they aren’t in the air, they can’t be sucked into the purifier, so they can’t be eliminated. Despite what some marketing campaigns claim, the average purifier is incapable of dealing with dust mites.
Can Air Purifiers Remove Mold Spores
Mold is one of the most common allergens, especially in climates with a lot of rainfall, humidity, and moisture. Mold particles are usually 3 to 100 microns in size, but some can be as small as 1 micron. Thankfully, most HEPA filters can remove particles as small as 0.3 microns, so you can be sure they’ll deal with mold spores in the air. Some filters even come with antimicrobial treatments that can prevent mold spores from reproducing in the filtration systems.
The problem is that the mold spores in the air are really just a symptom of the real problem: mold in your walls, attic, ceiling, floors, etc. The air purifier can cleanse the spores floating in the air, but the mold in your house will just release more spores. Think of it as a Band-Aid over an open wound—you need to get rid of the mold once and for all, then the spores won’t be a problem!
Types of Air Purifiers
Understanding the various types of purifiers and filters will help you know what options are available. First, let’s start with the types of appliances you can use:
Whole-House Purifiers – Think of this as an addition to your home HVAC system. They’re installed as part of the HVAC system, and they work to clean the air of your entire house all at once. They don’t do as thorough a job as smaller purifiers, but they can clean the whole house—making them great for those with severe allergies.
Portable Air Purifiers – These are the standard options for most people. They’re small enough to be portable and highly effective at eliminating particles (up to 99.97% down to 0.3 microns, if they use HEPA filters), but can only handle one room (or space) at a time.
Whole House Filters – These are attachments that are installed on furnaces and other openings in your home, and they are designed to filter any particles from the air that passes through them. However, they don’t usually come with built-in fans, and they’re less thorough at cleaning the air than either of the other two options.
There are a surprising number of filtration system options to choose from for your purifiers and filters:
HEPA – High Efficiency Particulate Arrestance filters are made with multiple layers of filtrating materials, which makes them the most effective at dealing with mold, dust, pollen, and other airborne particles. They can handle up to 99.97% of particles larger than 3 microns.
Carbon – Carbon filters are made using very porous activated carbon, which adsorbs (bonds with) the particles in the air. They’re more effective than HEPA filters at dealing with smoke, odors, and gases, and they can collect particles down to a molecular level. However, they’re not as effective for pollen, dust, and mold.
Titanium Dioxide – Also known as TiO2 filters, these use titanium dioxide to filter out germs, odors, and smoke. They’re typically used in commercial and hospital-grade air purifiers.
Ionizers – Ionizers create electrical charges that cling to the particles in the air, which grounds them and kills viruses and bacteria. They do not filter out particles, but simply cause them to fall to the ground. This means that the dust, pollen, and mold is still present, just clinging to your floors and carpets, where they can be vacuumed up easily. However, they may produce ozone, which can be dangerous for your health (see the next section).
Ozone – These air purifiers pump ozone into your home, and the ozone oxidizes the rust, mold, mildew, and particles in the air. It can deal with odors highly effectively, as well as allergens, pet dander, and other contaminants. However, it carries some potentially serious health risks (see the next section).
UV – These purifiers use ultraviolet light to kill off pathogens and bacteria in your home via electromagnetic radiation. They can kill off yeast, fungi, viruses, mold, and bacteria highly effectively. Sadly, they don’t deal with dust, odors, allergens, or any inert solid particles floating in the air.
Filters – Some filters use fiberglass, cotton, foam, or special synthetic fibers to filter out particles. The dense material only allows tiny particles through, so all the larger particles (including mold spores, allergens, dust, and so on) are trapped within the filters. The large surface area of the filters are effective at cleaning a lot of air at once, but they aren’t as efficient as HEPA filters.
What You Need to Know About Ozone
Ozone may help to filter out the particles in your air, but can be quite hazardous to your health. According to the EPA, “The same chemical properties that allow high concentrations of ozone to react with organic material outside the body give it the ability to react with similar organic material that makes up the body, and potentially cause harmful health consequences.”
The EPA’s list of “harmful consequences” includes:
- Lung damage
- Chest pain
- Throat irritation
- Shortness of breath
- Worsening of chronic respiratory diseases, like asthma
- Compromised immune response to respiratory infections
- Respiratory difficulty
Remember how ozone can quickly oxidize the particles in the air and cause them to “decay”? That’s what happens to the cells in your body when they’re exposed to ozone. The EPA’s stance is that even low amounts of exposure to ozone can be dangerous, leading to the above symptoms.
The California Air Resources Board has a list of “Potentially Hazardous Ozone Generators Sold as Air Purifiers”, appliances that emit large quantities of ozone. The ARB recommends that you avoid using these generators for your health’s sake.
Air Purifier Buying Guide
When planning to buy an air purifier, take a moment to consider:
Room Size – The size of your purifier will determine the amount of air it can clean. Smaller purifiers should be able to handle up to 155 square feet, roughly the size of a small room. Larger tower purifiers have a capacity of 300+ square feet, the size of a family room or bedroom. Some can handle up to 500 square feet, which makes them ideal for living rooms and larger, wide-open spaces. Think about what rooms in your house need to be purified, and buy an appliance that is the appropriate size for the space.
Filtration Systems – The list above (in “Types of Air Purifiers”) will help you decide which filtration system works best for your specific needs—allergies, mold, germs and bacteria, odors, or dust.
Noise Level – If you run a purifier in a room where you work or sleep, you’ll want to find one that’s as quiet as possible. Larger units can be set to run on lower speeds, and they’ll generate far less noise than a smaller unit running at top speed.
Operating Cost – Not only will your monthly electric bills increase, but you’ll need to budget in the cost of replacing filters. HEPA and carbon filters can be pricey, so expect to pay anywhere from $20 to $100 for a replacement. Consumer Reports estimates an annual running cost of up to $200.
Frequency of Cleaning – To keep the filtration system running well, you need to change or clean the filters at least every 3-6 months. A dusty, clogged filter won’t work to clean your air!
CADR – The Clean Air Delivery Rate is a third-party testing measure that lets you know how effective the purifier is at churning out clean air free of airborne particles. The higher the CADR number, the faster your purifier can clean the air going through its filter.
- For small rooms, get a CADR of as high as 97
- For medium rooms, get a CADR between 98 and 130
- For large rooms and spaces, get a CADR higher than 130
Here are a few of the features to consider when shopping for an air purifier:
Multiple Speeds – You don’t always need to run it at full blast. A multi-speed appliance lets you crank it up during allergy season and turn it down low to run quietly while you’re sleeping or working.
Fan – Consumer Reports tested fan-less air purifiers and found that they didn’t work as well as purifiers with built-in intake fans.
Servicing Indicator – A light or alert that lets you know when it’s time to clean or replace the filter is a very useful feature! After all, a clogged or dirty filter doesn’t work as well as a clean one.
Dirt Sensor – Some air purifiers have these built-in sensors that the adjust fan speed according to the presence of particles in the air. A great feature to help you reduce energy costs!
Programmable Timer – With this feature, you can set the purifier to run for a specific amount of time before switching off. This will help you clean the air in a room before or while you use it, but reduce energy costs significantly.
Ionizer – If you want to use an ionizer to attract particles (like static electricity), make sure it doesn’t generate ozone!
Where to Set Up Your Air Purifier
The placement of your air purifier will have a huge effect on how efficiently it’s able to clean the air in whatever room it’s in.
If you’re using a portable purifier (instead of a whole-house appliance), you should put it in the room where it’s needed most. This is typically the bedroom, office, or living room, as those are the rooms where you spend the most time.
- For overnight allergies, run the purifier in your bedroom at night.
- For pet allergies, run the purifier in the living room or wherever you and your pets hang out.
- For homes with smokers, run it wherever you want to get rid of the smell of smoke.
You want to find a place for your air purifier that is out of people’s way (so they don’t kick it, trip over it, or knock it over). However, if you put it in the corner of a room or against the wall, you could drastically limit air flow to the intake. This means you’ll get less purified air, reducing the effectiveness of the appliance.
As a rule of thumb, always make sure there is a foot or two of clearance between the purifier and the wall—on both input and output sides. The closer the purifier is to where you are, the faster you get clean air.
Note: It’s recommended that you avoid placing purifiers on or near other electronics. The electronics may work on similar wavelengths to the purifier, and it could cause interference with your TV, stereo, or microwave.
Remember, the purifier will only really do its job well if all of the doors and windows are closed and there’s no way for outside pollutants and allergens to get inside. Your purifier can’t clean all the air in the great outdoors. It’s only capable of cleaning one room (or house) at a time, so make sure to prevent any outside air from filtering in if you want to speed up the cleaning process.