Tuesday, September 22

Air Quality Explained: The best air purifier to help you stay healthy


This post was originally planned during the early days of COVID19 as a review of a home air purifier. I’m very concerned with indoor air as I suffer from horrific allergies that plague me daily. A day didn’t go by without my taking a Claritin or Zyrtec to make it through.

But as I was testing home air filtration, the West coast fires flared up and now, the outdoor and indoor air has become a real issue for everyone. One day I woke up and saw that my bedroom wasn’t bright; I looked toward the window and the world was coated with a gray orange haze.

I’m no novice to pollution. I moved to Los Angeles in the days of daily air warnings. I was in Shanghai a few years ago when the government implemented measures to clear the air for the G20 summit. For two weeks they suspended operation of 255 chemical plants and polluting enterprises to ensure blue skies for visiting diplomats. (Pro tip: It worked).

In January 2020, after returning from CES in Las Vegas, I observed there was something brewing in the sense of coronavirus. I ordered face masks from Asia, where masks are commonly worn for many reasons. Aside from preventing the spread of disease, stronger engineered masks are used by motorcyclists that filter out particulate matter down to 2.5PM using nanotechnology filters. As long as your PM2.5 mask fits tightly, you have a fighting chance for clean air (but may not necessarily protect from coronavirus – its “officially” recommended that you use a N95 filter).

We hear a lot about PM2.5, so let’s lay out exactly what it means. The air we breathe contains allergens, germs, smoke, viruses, bacteria and more. The PM stands for particulate matter; the 2.5 signifies the size of the particulate matter you want to avoid. So air pollutant particles you’ll be protected from have  a diameter of less than 2.5 µm (microns). To illustrate, a human hair is approximately PM70, most particle air pollution is PM10; and can penetrate your lungs and even filter into your bloodstream. They include smoke, automotive exhaust, bacteria and viruses. (I was even shocked to see dust appear from unrolling a roll of toilet paper.) The finest pollutants are 2.5 and below.

Durig the height of the wildfires, my backyard looked like an old, faded photo. The blue light was being blocked by the particulate matter and everything had a dark yellow hue, due to pollutants. Our air quality is measured by Air Quality Index (AQI). This is a measure developed by the Environmental Protection agency to measure (and compare) pollutants circulating in the air.

Here’s a chart from the EPA's AirNow.gov to illustrate the levels and how they affect humans.

To check the AQI of any location, go to the government site, airnow.gov. AirNow uses the official U.S. AQI in partnership with the EPA, Noah, NASA and many other air quality agencies.

You can also check out your local AQI at purpleair.com, just click View the Map on the home page. PurpleAir sells sensors to the public, so the site is compiled through user generated data from the people who participate in the site.


Now, back to the point of this post. Levels inside the home may not necessarily be lower than outside. Outdoor air pollution seeps into our homes everytime we open a door or through cracks in windows and walls. We affect our own indoor air every time we cook, dust, vacuum, light a candle, turn on the air conditioning, open a window – basically everything we do to live our lives normally. Aside from activities, any home or apartment has its share of cracks and openings that we can’t see that allows polluted air into our homes.

I started this deep dive to review an Airdog X5 air purifier. I was assured that this was the latest technology. Being cognizant of the dangers of bad air, for years I’ve had various forms of air purifiers in my house; mostly HEPA filter purifiers.

HEPA Filters

Until I accepted the Airdog X5 for review, I felt my house was protected since we had several  (expensive) Dyson Pure Cool Link HEPA Tower units in our home. They have industry standard sealed activated carbon HEPA filters -- plus Dyson's own air puification technology. As fans, they do a great job of circulating the air; as air purifiers, I assumed they were doing their job since HEPA filters remove 99.97% of allergens when they are new. (The longer they are is use, the more clogged and inefficient they get).  

My second misgiving about them was the fact that HEPA filters must be changed.  After a couple of month of use, one of our Dyson HEPA filters showed a remaining filter life of only 60%. (We have not opened windows during the fire season). The new, circular replacement Glass HEPA filters cost about $70 and are recommended to be replaced at least once a year, but as you can see by my filter life, I'm going to have to purchase a replacement much sooner.

The recyclability of HEPA filters is a hit-or-miss proposition. Plain paper doesn’t make a HEPA filter; there’s the addition of polyester and fiberglass to really give a HEPA filter the strength it needs to filter at .3 microns.

Airdog X5

I was pleasantly surprised to see that this air purifier is a beautiful device. It will look great in any hone, office or industrial situation. The entire unit is 26” x 12” x 12’ and only weighs about 22 pounds. Once I set it up I saw this was a fully innovative technology. I turned it on in the same room as the Dyson and its display registered a moderate amount of pollution in the room!

There is no HEPA filter in the Airdog. There are washable collecting plates which once get coated with  pollutants from your home can be easily cleaned in the dishwasher or your kitchen sink. There are also catalyst filters that can be rejuvenated by placing in sunlight for an hour or so.

Airdog uses their own proprietary ionic tech.  Their patented TPA® technology has been tested as a most effective clean air solution. Their material states: “Airdog air purifiers destroy and eliminate particles down to 0.0146 microns." This level of air purification takes care of smoke, bacteria, pollen, viruses (including COVID-19), pet dander, formaldehyde and odors.

The technology

On the Airdog X5, air is sucked in though vents at the bottom of the device. Even though the very smallest of particulate matter weighs very little, eventually gravity brings it all towards the ground.

  • Step 1 is a pre-filter screen which filters out the largest items like hair, pet dander etc.
  • Step 2 is a simple wire frame. These Emitter Wires create an electro-field that zaps dangerous particles that would be traveling into our lungs.
  • Step 3 Ionic field: Here's where particles previously charged by the emitter wires are destroyed. It kills bacteria and germs. This step has been 3rd party lab tested and confirmed to kill 99.87% of influenza virus in one hour. The app or the LCD display will let you know when its time to clean.
  • Step 4 is the washable collecting plate. The charged particles from the ionic field stick to the collecting plates to remove even more dangerous toxins from the air. The collecting plates are then washed and reused over the course of time.
  • Step 5 The final step is the catalytic layer; the final step in the purification process that removes unpleasant odors - keeping your air fresh and pure.

The only issue that gave me pause about the new technology was the reference to ionic. Ionic air filters create ozone. Ozone is a known and dangerous pollutant. The California Air Resources Board highly tests all ozone emitting devices for safety. After thorough testing, they approve devices that meet their stringent standards. Here’s a link to a chart of portable indoor air cleaning devices that are certified by the California Air Resources Board (CARB). To be certified, air cleaners must be tested for electrical safety and ozone emissions, and meet an ozone emission concentration limit of 0.050 parts per million. The Airdog meets those stringent standards.

So I set up the Airdog and moved it around 24/7 to “see” the air cleanliness in my home. It can run in Auto mode that adjusts the fan speed according to the pollution levels in the room. The front of the Airdog has an LCD display that lets you know the current AQI in your room.

I was a bit alarmed to hear the Airdog fan ramp up (indicating pollutants) when it was in the same room as my Dyson. I just figured the Dyson had the room covered, but I was wrong. The Airdog found the finest of particulates to remove; far more than the HEPA filter did in the other air filter. Once the air was cleared in the room, the fan automatically settled down and the AQI was back to a safe range.

More importantly, I noticed that, after two nights of sleeping with the Airdog, my allergies disappeared and have not reappeared – as long as I keep my Airdog on auto mode 24/7.

The Airdog X5 works both through an app or with a manual remote which allows a non-techie to ramp up the fan, turn on Auto mode and to initiate night mode (which switches the unit into auto and turns off the LCD display).



All in all, the Airdog X5 is the best air purifier I’ve ever used – and I’ve had decades of experience – trying to have a home with clean air. Its not cheap at $599, but considering the accuracy and savings with reusable parts, it seems like it will balance out over time.

A big plus as well, is the fact that I no longer have to feel guilty disposing of un-recyclable giant HEPA filters.