Air filters: a guide to smart and less smart models than Covid-19 and wildfires are driving demand

The wind had carried smoke from a distant fire in the Bay Area, an increasingly common occurrence where I live in Northern California, and the Air Quality Index, or AQI, which is a measure of pollution, worsened accordingly. I closed the patio door and Mila continued to purr in the background.

Forest fires are not the only concern driving the demand for air purification devices. In addition to capturing smoke, gadgets can remove dust, pollen, and other allergens from the air. And according to the US Environmental Protection Agency, air purifiers with the right filter can even reduce the spread of germs, including the coronavirus. Some experts recommend bringing a portable filter with you to work.

As I embarked on my quest to purchase an air filter, I was overwhelmed by acronyms and marketing jargon. What do the specs mean? What distinguishes the different filters? How much do I need to cover my house? Is a “smart” Internet connected model really a smart decision?

I asked experts. Researchers, Respirologists and Allergists Agree: Air filters can help us lead healthier lives, but the right device for you largely depends on the types of contaminants you want to filter out and the size of your room. .

Why buy an air filter?

Dust, pollen, and smoke affect the air quality in and around your home. If you live in an area affected by pollution or are sensitive to allergens, you should consider installing an air filter. The EPA defines AQI values ​​greater than 101 as unhealthy for sensitive people, and greater than 151 as unhealthy for everyone. The AirNow website displays local AQI data in the United States, and the IQAir map displays global information.

Vulnerable groups, including the elderly, children, pregnant women and people with asthma, may experience immediate irritation of the eyes, nose and throat, and after continued exposure, headaches and fatigue said Juan Aguilera, researcher at Sean N. Parker Center for Allergies and Asthma.

A filter can circulate air and remove inhalable contaminants, he said, adding that keeping doors and windows closed is crucial in combating external pollution or allergens.

Tiny particles, such as smoke from wildfires, can enter the bloodstream and prolonged exposure can lead to chronic inflammation, heart disease and other chronic illnesses, Dr Aguilera said. These smaller particles are called PM2.5, or particulate matter less than 2.5 microns in diameter. There is also PM10, which includes larger mold spores. Ideally, one device should filter out both types of particles.

Can air filters prevent the spread of Covid-19?

Air filters can help but cannot stop the transmission of the virus on their own, says Stephanie Christenson, pulmonologist and assistant professor at the University of California, San Francisco.

High-efficiency particulate air filters, or HEPAs, can remove the tiny particles that contain the virus, but “if someone with Covid-19 coughs or talks near you, respiratory droplets can get to you before they have the chance to filter. , making masking and distancing so important, ”she said.

What are the specifications and certifications to consider?

We have already discussed PM2.5, which are the smallest and most dangerous particles, as well as HEPA filters, which James Sublett, former president of the American College of Allergy, Asthma and Immunology, says are the best. choice for air purifiers. . Look for true HEPA, defined as removing at least 99.97% of airborne dust, pollen, mold and bacteria, on labels. Terms such as “HEPA-type” and “HEPA-type” are not sufficient.

Here are some acronyms you should be aware of when trying to decipher Clean Air Alphabet Soup:

• CADR or Clean Air Delivery Rate: The higher the CADR, the larger the room it can filter. The EPA recommends a minimum CADR of 65 per 100 square feet, in rooms with 8-foot ceilings. (Taller rooms will require a higher CADR.) To eliminate viruses, the agency recommends looking for a high CADR for smoke, relative to pollen and dust, and a HEPA filter.

• AHAM or Association of Home Appliance Manufacturers: You’ll likely come across filters with an AHAM Verifide logo, and the doctors I’ve spoken to recommend this check. The group certifies the ability of a filter to remove three sizes of particles.

• CARB or California Air Resources Board: The government agency requires that all air filters sold in the state be tested for electrical safety and ozone emissions, which are limited in California. At high levels, ozone can be toxic to the respiratory tract, Dr. Sublett said, and is created by devices marketed as “ionizers” or “ionics.”

• YOUs or volatile organic compounds: These are gases, which cannot be eliminated by HEPA filters alone. Your air filter will need an activated carbon filter for this.

Now that you know your ABCs – or rather your CACVs – you can take a better look at the labels: Does the air purifier have a HEPA filter? Is it AHAM or CARB certified? What is the CADR rating? Is the filter designed for VOCs?

Are smart filters worth it?

The Internet of Things generally improves lives (hello, smart thermostats) and sometimes gets carried away (hello, self-flying home security drone).

Manufacturers have crammed air purification gadgets with sensors, automation, and Wi-Fi and Bluetooth antennas. Most smart models can be controlled by a mobile app, and the best ones automatically adjust to changing air quality.

The smart filter I tested, Mila, starts at $ 349 with a filter subscription and $ 408 without. Replacement filters cost between $ 59 and $ 99 per piece, depending on the level of protection desired. There is one specially designed for pets, for example, with an external pre-filter cover to capture fur. The device contains several sensors for detecting particles, humidity and carbon monoxide, and its illuminated display shows the indoor air quality assessment, as well as data from the outdoor sensor network of PurpleAir.

Mila is a bulky device, measuring a foot wide and 15 inches high, about the size of an all-in-one printer or desktop coffee machine.

The filter included in my review unit, called the Critter Cuddler, has a CADR of 350 and, according to EPA guidelines, can accommodate a room of about 500 square feet with 8 foot high ceilings.

When I burned a piece of toast, Mila reacted quickly and turned up the fan. My PM2.5 sensor ($ 80 from Amazon) confirmed the particle spike and the filter cleaning quickly. I like Mila’s Turndown Service mode, which I activate from my phone. An hour before my preset bedtime, Mila’s fans show up to reduce nighttime allergies, then automatically calm down when it’s time to sleep. Being able to monitor indoor air quality remotely is also a great feature. Soon Mila will alert you to active forest fires nearby.

But, as is often the case with smart products, I ran into some bugs. The touch buttons stopped working and I had to reset the device. Then the outside air reading stopped showing on the screen. The company said the touchscreen issue only affected a few customers, including me, and the air quality display bug was fixed.

For those looking for the convenience of a filter that dynamically adjusts and can be controlled remotely, and who have the technical knowledge to troubleshoot if something goes wrong, a smart filter may be a good option. Otherwise, I think most will find an analog air filter perfectly sufficient. (I like Blueair’s relatively quiet models.)

“A smart air purifier can give you a bit more information on how well it works, but it’s definitely not the most important characteristic of a purifier,” said Dr. Christenson. A good quality system, properly rated for the size of your room, is essential, she said. In other words, many of those mini portable cleaners on Amazon without certification and without HEPA filters won’t cut it.

For now, the air in the bay area seems clear, so I turned on Mila’s power save mode, which keeps her display and fan off as long as the air quality is good. good. In the app, he wrote ominously, “Don’t worry, I’m still smiling, judging and watching. 😉 I will shoot if I find any problems. Just what I’ve always wanted: an air filter that winks.

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Write to Nicole Nguyen at [email protected]