The Brondell O2+ Halo True HEPA Air Purifier has a sleek design. Images courtesy of manufacturers.

March 25, 2020 

This time of year, Texans are bombarded by pollen and dust, and experts suggest that the air inside our homes may be even more polluted than outside.

Now lately with the coronavirus circulating throughout our communities, you may have wondered how much additional protection an air filter could provide. According to a recent BuzzFeed article - none.

“Your typical HEPA filter is not going to be able to remove coronavirus from the air,” said Dr. Erin Sorrell, an assistant professor of microbiology and a member of Georgetown’s Center for Global Health Science and Security told BuzzFeed. “The filter itself is .3 microns and the virus itself is roughly .1 microns.”

While a UV filter does kill some viruses, Sorrell said it won’t affect coronavirus as the HEPA filter is not fine enough to suck it up from the air. Even if it could, the process “typically takes about 15 minutes but it varies across viruses.” It’s not clear how long coronavirus would take to kill using UV, Dr. Sorrell clarified.

Dr. Aaron Glatt, an Infectious Diseases Society of America spokesperson agreed, saying the exposure of the virus to UV light “would have to be significant, it could not just be for a second.”

Researchers believe the new coronavirus is spread primarily through droplets as opposed to aerosolization, according to STAT, a health and science journal produced by the Boston Globe

However, according to the American Lung Association poor indoor air quality can cause or contribute to the development of infections, lung cancer and chronic lung diseases such as asthma. 

In the spirit of improving the health of your home environment, below are some tips for improving your indoor air quality and a guide to some of the most popular air filters on the market.


According to the American Lung Association, the most effective way to improve indoor air quality is to reduce contaminants in the first place: 

• Stop smoking (!!) or do it outdoors.

• Use a HEPA-filtering vacuum cleaner often.

• Wash sheets, curtains, rugs and other fabrics frequently.

• Brush pets often and discard the fur into your composter.

• Minimize carpeting and use door mats at all doorways.

• Eliminate artificial scents in detergents, candles, air fresheners, etc.

The Cleveland Clinic has some other tips for reducing indoor air contaminants.


Increasing the houseplants in your home can also help to clean the air. A 1980s NASA study resulted in a list of beneficial plants that help reduce various contaminants. (Warning: Lilies are deadly to cats.)

Aloe vera is one of the house plants recommended by NASA to clean indoor air. Photo by Jason Winningham.

If you’ve completed all of the low-tech solutions and are still having air quality issues, consider adding an air filter to your home. The EPA offers a free guide to choosing a residential air filter. In it, they describe the two major types - whole house filters and portable air filters.


Talk to your HVAC professional about upgrading your home’s heating and cooling system to accept a thicker filter or even an electrostatic filter. Consumer Reports notes, “the thicker the filter, the better it works and the longer the replacement intervals. That means it’s better for you and for your HVAC system.”

April Air filterMERV 13 filter. Courtesy of Aprilaire.

I recently moved into a home that has a four-inch thick filter system that augments my Lennox HVAC. I replaced the filter with an Aprilaire 213. According to Aprilaire, the MERV 13 filter traps “dust, pollen, mold spores, bacteria, pet dander, and dust mites.” 

The filter only has to be changed once per year though the cost is around $75 each, about 10 times more than a standard replacement filter. It seems to be worth it. In actual use, I have found that dust and pet hair are much less than my former house that did not have this type of system.

If upgrading your entire system is prohibitively expensive, you can probably just buy top-quality filters for your current HVAC system. Even just changing a basic air filter in your HVAC system to a better version can significantly help to improve your indoor air quality. 

Regardless of the model that you choose, make sure to select a High-Efficiency Particulate Arrestance (HEPA) filter with a MERV (Minimum Efficiency Reporting Value) rating of 10 or greater to remove even the smallest pollution particles. HEPA filters trap as much as 99 percent of dust and other particulates. However, HEPA filters don’t affect radon or ozone that can also cause health issues. Also, some air purifiers use UV light or electrostatic charges for controlling viruses or bacteria. If that is a concern, you may want to augment your HVAC system with a portable air cleaner.


The Nordic Pure Green filter is made from recycled pop bottles.

Of course, air filters themselves create landfill waste. One option is to choose eco-friendly filters such as Nordic Pure Green, made from recycled pop bottles.

TrophyThe company indicates that they can be recycled again at end of life cycle. Some companies are also making an effort to create more eco-friendly filters. By eliminating metal in their Filtrete models, 3M will help to reduce over 3.5 million pounds of landfill waste each year. 

The Trophy, above, and Web Eco filters can be rinsed and used again.

WEB Eco“The goal was to keep the performance the same,” said Carrie Sazama, marketing manager of Filtrete Brand Air Filters. “We’ve done that, with no change in performance.”

Washable air filters are another option such as Web Eco or Trophy. Though they have a lower MERV rating, they can be rinsed out frequently, helping to eliminate allergens even for sensitive users. Many carry a lifetime warranty so replacement costs are minimized.


Also known as air purifiers or air sanitizers, fan-driven portable air filters help to remove contaminants in a particular area (no pun intended). They are offered in a wide variety of models and styles. Some remove dust, others remove smoke and other gasses and still others have UV lights to help kill germs and odors. We received feedback on three popular models in readers’ homes and offer this non-scientific snapshot-

Germ GuardianGERM GUARDIAN – from $85 to $180

Guardian makes a wide variety of units, from countertop models to large floor units. Most are rated for single rooms such as a bedroom or den, with HEPA filters and optional UV lights for germ reduction. Fancier versions even feature WIFI and Bluetooth to allow for voice control through Alexa or Google Assistant. Most offer an optional “auto mode” that detects particulates and then adjusts the fan speed to filter your home’s air. Some connect with the Guardian smartphone app that allows you to monitor your home’s air quality and alerts you to change a filter or UV bulb. 3 year manufacturer’s warranty. Energy Star rated.

According to the company, Guardian’s “HEPA Filter captures 99.97 percent of dust, pet dander and pollen while the charcoal filter gets rid of nasty household odors. UV-C light technology works with Titanium Dioxide to kill airborne bacteria, viruses, germs and mold spores.” 

One of our testers purchased the Guardian AC4825 Air Purifier ($85 on Amazon) that offers 3 speed settings and an optional UV C light to help control pet dander and other allergens.  

She commented, “Since we put a Germ Guardian floor model air filter by our bed, I feel like I sleep better at night and breathe better. My nose does not tend to get stuffy like it used to. It’s plain to see when I change the filter every 6 months, that it is definitely pulling in dust and pet hair.”

Another tester bought the upgraded CDAP5500 Air Purifier ($134 on Amazon) with WIFI and Bluetooth plus a programmable timer. She was impressed with the varied features of the unit including the option for the voice assistant. With 5-speed settings including an auto-quiet mode, she appreciated that it allowed her to sleep even while it was running. 

“My daughter has two of these and liked it so much that she ordered one for me. It has really helped to cut down on dust and odors in my home.”

PROS: Lower price point with multiple options.

CONS: Multiple units would be necessary to cover a typical home because of the limited square footage per air purifier.


Brondell air filterRated for medium-sized rooms at around 157 square feet, the Brondell O2+ Halo True HEPA Air Purifier has an attractive sleek design without the designer price tag. The company claims that its Certified True HEPA filter and woven carbon technology removes airborne particles, gases and allergens including dust, smoke, pet dander, mold spores, pollen and odors. 

“Many competitors concentrate too greatly on their HEPA filters in an effort to move as much air as possible through the system. They disregard the benefits of other filters that help to more effectively clean the air”, says Steven Scheer, Brondell’s president.

The Brondell features three-stage filtration: a washable micron mesh pre-filter extends the lifespan of the other two filters by capturing large particles, a carbon filter reduces smoke, odor, and harmful VOCs, and the HEPA filter removes 99.97 percent of particles and allergens above 0.3 microns. In addition to the standard replacement filter pack, a granulated carbon deodorization filter pack is also available. The Brondell O2+ Halo offers 3 fan speeds and is rated at 5.5 air changes per hour (ACH) with an entire room of fresh air about every 11 minutes.

The Brondell also sports an air quality indicator with colored LED’s depending on severity of contamination, auto mode that adjusts depending on the contamination level, filter change indicator and auto off timer. Three-year manufacturer’s warranty. Energy Star rated.

PROS: Our tester gave the Brondell high marks for ease of use and attractive, sleek design. He noted a marked reduction in odors, dust and pet dander. 

CONS: The fan noise was noticeable on the higher settings. The lowest setting was quiet enough to run 24 hours per day without being disturbing.

ALEN – $688

Alen Breathsmart filterOne of the highest-rated portable air filters on the market, the Alen BreatheSmart Classic covers a large area of up to 1,100 sq ft. The Austin-based company offers multiple colors and wood tones from which to choose to match one’s décor (may increase price). The unit’s HEPA filter removes pollen, dust, pet hair, dander and other allergens. 

Alen’s patented WhisperMax technology reduces noise while its large motor pulls air through the filter with rounded-baffle fan blades, developed by Alen with a former NASA engineer, emitting both a soft white and pink noise that the company claims can improve sleep by 25 percent. The company’s specs indicate that the unit will trap 99 percent of airborne particles down to 0.3 microns.

Alen offers several different HEPA filter types: for allergy and asthma relief, additional protection against bacteria, for chemicals and cooking odors, and extra defense against smoke and pet odors. Our tester found that the BreatheSmart “helped to reduce dust, cat hair and other irritants significantly,” in his home.

According to Alen’s website, “Polluted air first passes through Alen's replaceable pre-filter to capture large particles, extending the life of the filter. In the second layer, air moves through a unique, electrostatically charged HEPA type material that attracts and captures dust, pollen, light smoke, mold spores and other airborne pollutants. In the final layer, clean air passes through a layer of Alen's activated carbon, reducing light odors and chemicals commonly found in the air from cleaning products, light smoke, cooking, and various other household materials.”

Like the Brondell, the Alen purifier has a color-change LED air quality indicator and auto mode that adjusts depending on the contamination level. It has frou fan speeds. The top level, turbo, is able to clear a room quickly when the unit has been off for awhile, such as when the user returns from vacation. On turbo speed, it is rated at 286 CFM, cubic feet per minute, with an entire 1,100 square foot space of fresh air about every 30 minutes. In addition, the Alen purifier comes with the industry's first and only forever guarantee (see Alen’s website for more info). Energy Star rated.

PROS: Our tester noted that the fan noise is almost undetectable and the attractive design blends well with his color scheme. 

CONS: The price was on the higher end but our tester felt that it was worth it as he is suffering with COPD and needed the extra filtering capacity of this unit.



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