Air purifiers are becoming a growingly essential device in our everyday lives. But how do you chose an air purifier for home that really improves your health?
With the allergy season well upon us, people suffering from allergic symptoms will do what they can to combat the allergens floating in the air, particularly at home. Regardless from the season, clean air is crucial for our lungs, blood circulation, heart, and other organs to function in a healthy way. But it has been proven that the air inside your home is actually dirtier than you think.
According to the Environmental Protection Agency (EPA), the concentration of micro pollutants is often two to five times higher in indoor spaces than outdoor.
Air pollutants such as smoke from tobacco, wood, and cooking; gases from cleaning products and building materials; dust mites; mold; and pet dander all contribute to poor indoor air quality, that can have ill effects on the body. These dangerous conditions have been only intensified by the occurrence of more and more frequent wildfires, as well as the SARS-CoV-2 Pandemic.
Micro particles which are less than 10 micrometers in diameter are especially concerning as they can make their way deeper into the lungs than bigger particles. Breathing them in for just a few hours or days is enough to potentially damage your lungs. Micro particles have also been linked to heart attacks in people with heart disease, and several studies show that long-term exposure to high micro particle levels may even cause bronchitis, impaired lung function, and premature death.
On top of that, volatile organic compounds (VOCs) are constantly released into the air from adhesives, paints, and cleaning products. Exposure to VOCs can cause nose, throat, and eye irritation; headaches; nausea; and damage to the liver, kidneys, and nervous system. Finally, some gases, such as radon, can cause lung cancer and death.
How Air Purifiers Can Help
The best way to improve indoor air quality is to remove the source of pollutants and ventilate with fresh, clean outdoor air as soon as possible. Home air purifiers can help when those methods alone are insufficient.
Home air purifiers are normally designed to filter the air in a single room, not the entire house, while whole-house “fixed” air purification system is usually integrated into a home’s heating, ventilating, and air conditioning system. Although home air purifiers help to reduce indoor pollution, there are limits to what they can actually do.
What Air Purifiers Do Well
The air purifiers that perform best, have been lab tested filtering dust, smoke, and pollen from the air. Numerous studies of home air purifiers show that using HEPA filters – the most common type – results in reductions of around 50% of air particulate in around 3 hours.
But how does that affect your health? Almost a dozen studies, like the ones conducted in Vancouver, British Columbia; Taipei, Taiwan; and Massachusetts, analyzed the cardiovascular effects of air purification and showed a clear improvement in cardiovascular health among participants. An EPA review of eight studies also found that purified air delivered modest improvements in at least one health area, such as allergy symptoms. And asthmatic participants in a 2018 study by the University of California reported a 20% reduction in clinic visits after improving the air quality in their homes.
Still, there are limitations. The scientific and medical communities have not definitively linked the use of air purifiers to health benefits, because reported health benefits are inconsistent among participants and so far there have been only a limited number of long-term studies.
As for the coronavirus, air purifiers with HEPA filters are capable of capturing the droplets that the virus travels in (when people cough, talk, or breathe). But you’ll need one that consistently draws in enough air to reduce the virus particles floating in the air to be actually safe.
What Air Purifiers Don’t Do
An air purifier can remove allergens only while they’re floating in the air. Larger, heavier allergens, such as mites, mold, and pollen, settle to the ground so quickly that most air purifiers struggle to capture them in time.
What We Don’t Know
Radon gas is another blind spot for air purifiers. Studies are inconclusive on air purifiers’ ability to tackle this extremely dangerous gas. This is mainly because there is insufficient research on air purifiers that address gaseous pollutants as a group, so it’s unclear how effective they are in that regard. There is also limited to no data on the effect of ionizer air purifiers on health.
That brings us to another important consideration when it comes to choosing your home air purifier: the various kinds of air purifier technology available.
Different Types of Air Purifiers
There are several technologies air purifiers employ for reducing indoor air pollution. Some work better than others, and some can even be detrimental to your health.
Air purifiers with mechanical filters use fans to force air through a dense grid of fibers that traps the particles. The most famous type of filters using this technology are HEPA filters. These filters can remove larger and small particles, including dust, pollen, and some mold spores, while they’re suspended in the air.
As for their limitations, mechanical filters don’t help in any way with gases and odors. And they can be quite expensive to maintain. Mechanical filters are non-recyclable, normally needing to be replaced every 4-6 months, and they can cost up to $200 per filter.
Activated Carbon filtration
Rather than capture air pollutants particles like mechanical filters, sorbent filters use activated carbon that can capture some odor-causing molecules from the air. They can also tackle some gases, but they’re not particularly effective against the most common ones: formaldehyde, ammonia, or nitrogen oxide.
Because activated carbon filters don’t eliminate particles, many modern air purifiers will have both an activated carbon filter and a mechanical filter for catching particles. Activated carbon gets saturated quite fast once exposed to air, and requires replacement more frequently than a mechanical one. Make sure to budget for replacements accordingly: activated carbon filters cost up to $50 each, and you may need up to 6 of these bad boys a year to make it work.
These devices produce ozone, a molecule that can react with certain pollutants to alter their chemical composition.
This can result in dangerous indoor air quality, and we strongly do not recommend these types of air purifiers. Makers of ozone generators often claim that these devices emit safe levels of ozone, but several independent tests found that even at low settings, ozone generators can quickly exceeded the Food and Drug Administration’s limit of 0.05 parts per million for device.
Additionally, studies reviewed by the EPA have shown that low levels of ozone don’t effectively destroy indoor pollutants. Research also shows that ozone has been linked to decreases in lung function and increased risks of throat irritation, coughing, chest pain, and lung tissue inflammation. Ozone exposure might also worsen asthma, emphysema, and bronchitis.
Electrostatic precipitators and ionizers are devices that charge particles in the air so that they stick to plates on the machine thanks to a magnetic-like force. These type of air purifiers are pretty new on the market, and despite their claims have so far failed to deliver very positive results. On top of that, these devices can produce some ozone.
Ultraviolet Germicidal Irradiation (UVGI)
While some manufacturers of UVGI air purifiers claim their devices can kill airborne viruses, bacteria, and fungal spores with UV lamps, some bacteria and mold spores are resistant to UV radiation. To work, the UV light must be powerful enough and the exposure must last long enough to be really effective.
While the use of UV-light for killing germs and bacteria has been widely documented and applied in a variety of fields, these technology alone may not be sufficient to effectively filter all pollutants from the air.
Photocatalytic Oxidation (PCO)
PCO can be seen as an improvement of UVGI technology, as it uses ultraviolet radiation in conjunction with a photocatalyst, such as titanium dioxide, to produce hydroxyl radicals that oxidize gaseous pollutants.
Depending on the type pollutant, this reaction can generate byproducts, but some of the most advanced photocatalytic filters on the market are designed to turn these byproducts into harmless salts.
Although there have been only a few documented investigations done on the effectiveness of PCO air purifiers, mounting evidence shows that these devices can effectively remove all of the VOCs typically found in indoor air.
How Air Purifiers Are Tested
To see how well these machines clean the air, most lab tests inject smoke and dust into a sealed chamber and use a particle counter to measure the change in air particle concentration in the room.
It’s important that the test is conducted using particles as small as 0.1 and up to 1 micrometer. For particles larger than 1 micrometer, such as pollen, consider that any air purifier that scores well for smaller particles should be reasonably able to handle larger airborne particles as well.
Because most air purifiers have several speed settings, test for dust and smoke removal should always been conducted on both the highest and the lowest speeds. It’s also crucial to measure noise levels at every speed setting that a machine has. And since all air purifiers must be running almost at all hours to be truly effective, we calculate annual operating costs, which include filter replacements and energy use to run the machine 24 hours a day for an entire year.
What to Consider While Shopping for an Air Purifier
Cost of replacements
As a general rule, you should replace filters (or clean them, if they are reusable) every 4-6 months for mechanical (HEPA) filters, and every 2-3 months for activated carbon filters. Most devices have an indicator light that lets you know when to change (or clean) the filter. The costs of filters vary widely: they can range from $20 to more than $200 a pop, and filters with odor-removing carbon can cost as much as $50 each.
There are a couple of labels you may want to look for on the packaging of your air purifier. The first one is the Energy Star logo. Air purifiers must run around the clock to be effective, and you should factor in the energy cost when you shop. Energy Star certified purifiers are 40% more energy-efficient than standard models.
You may also see an AHAM Verified seal, which means that the Association of Home Appliance Manufacturers has tested the model. Many air purifiers have undergone AHAM’s voluntary certification program, which provides clean air delivery rates (CADRs) and room size guidelines on the seal.
The CADR rating indicates the volume of clean air that an air purifier produces on its highest speed setting. In our independent tests, a CADR above 240 is normally an Excellent rating; 240 to 180, Very Good; 179 to 120, Good; 119 to 60, Fair; and anything under 60 is considered of Poor rating.
If an air purifier has an AHAM Verified seal, you can trust that the unit can handle the suggested room size listed on the seal. Be wary about manufacturers’ claims, though. A thing you can do to be sure to have the correct device for you room size, is considering sizing up. Most of the models that are suitable for large rooms still work perfectly well – arguably even better – at lower, and quieter, speeds, which is a nice bonus if you need complete silence when you sleep.
To judge an air purifier properly, we should not just look at how well it performs but also at how well we’ll be able to live with it. Because these machines should always be running, ideally they should also be quiet. You should be able to find how many decibels a model operates at on its packaging or website listing before you buy it.
Other tips for minimizing noise from an air purifier: Run the unit on its high-speed setting when you’re not in the room, and turn it down to sleep (or low) when you’re needing some more silence.
How to Get the Best out of Your Air Purifier
Clean or replace filters often
An air purifier can’t run efficiently if it has a dirty filter. Typically, you should replace filters every 4-6 months for mechanical filters and every three months for activated carbon filters.
Chose the right placement
If you have just one unit, put it in the room where you spend the most time. For most people, that’s the bedroom. Make also sure to place the air purifier in a spot where nothing can obstruct airflow like curtains, decorative objects, and even walls.
Keep an eye on the speed
To avoid noise disruptions, we suggest running the unit on its high-speed setting when you’re not in the room and turning it down to low when you’re sleeping. Alternatively, you can buy an air purifier certified for a larger area so that you can run it on a low speed and still have it work effectively.
Other Ways to Improve Indoor Air Quality
If indoor air pollution is a problem and you want to improve the quality of your indoor air, there are a few simple things you could do to fix it before thinking about purchasing an air purifier:
Air purifiers can’t effectively remove all the larger allergens like dust mites and pet hair, that settle on furniture and carpets unless they get disturbed and redistributed into the air.
Open your windows on nice days to let in clean, dry outdoor air.
Use an exhaust fan in the kitchen
Do the same in bathrooms and laundry rooms.
Reduce the use of chemicals
Limit chemical-heavy cleaning products, and don’t store paint, glues, or insecticides near your living quarters.
Stop smoking indoors
That also goes for burning candles and wood fires.
A conclusive note
Air purifiers really work, and are effective at reducing the particulate matter in the air. Some types can lead to health benefits for those with allergies, asthma, and other conditions.
However, there are many factors to consider when choosing the most effective air purifier. HEPA filters have the most research to support them and can filter extremely small particles, however recent technologies are showing comparable and sometimes better results than HEPA filters, while drastically improving on sustainability, design, and connectivity.
Air purifiers are becoming more and more accessible and easy to purchase. Giving one a try might make a difference in the comfort level you experience at home.