The Science Of Clean Air, And My Honest AirDoctor Air Purifier Review

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Did you know that in 2009, less than 10% of the 85,000 chemicals registered for commercial use, had undergone basic testing for safety? Furthermore, toxins like carbon monoxide, lead, nitrogen dioxide, and ozone regularly appear in our air. Unfortunately, our environment today is awash in a slew of toxins doing a sinister number on our health. 

Needless to say, I am all about a non-toxic environment. A large portion of that starts with what we breathe.

I’ve tried many air purifiers throughout my life. Historically I’ve loved (and still recommend) Alen and Molekule. However, I recently came across a newer brand, and was allured by its high standards, coupled with approachable price tags. Indeed, AirDoctor was founded, in part, on a mission to make clean air affordable! As a girl with 5 air purifiers in my single bedroom apartment, you can bet I’m loving this concept! 

(Just how seriously do I take my air quality? Well, when the air duct inspector people in my apartment complex came to check my vents while evaluating hundreds of units, they specifically commented that my apartment had the cleanest air in the entire complex. That, my friends, is how you know you’re doing something right.)  

Why Air Purifiers 

High quality air purifiers can be incredibly effective at reducing airborne pollutants in one’s environment, including dust (which can contain lead!), mold (and their mycotoxins!), pollen and pet dander (oh hey allergies!), smoke (lung cancer, anyone?), viruses and bacteria (no comment there), and toxic compounds known as volatile organic compounds (VOCs), such as formaldehyde and other noxious gases. 

All of these compounds can trigger respiratory symptoms, allergies, and contribute to our overall toxic burden. Studies have shown air pollutants can increase respiratory issues, heart disease, and even the risk of cancer. Houses with reduced ventilation in particular, have been shown to contain higher VOCs, which increase cancer risk.  

What is AirDoctor?

AirDoctor was founded in 2016 by Peter Spiegel and Kate Williams, on a mission in part to provide everyone access to professional quality air purification at an affordable price. They’re all about transparency, and regularly provide third party validation for the different types of airborne pollutants. Their current lineup provide three professional grade HEPA filtration air purifiers: AirDoctor 1000, AirDoctor 3000, and AirDoctor 5000.  (I have the AirDoctor 3000.)


How to Choose a Good Air Purifier

There are some primary factors to consider when choosing an air purifier: true HEPA filtration, additional carbon filters, and the CADR rating and air change rates. (There is some nuances to these, as discussed in a bit.)

HEPA stands for “High Efficiency Particulate Air,” and is a designation used to describe filters that can trap 99.97 percent of particles that are 0.3 microns. This is an official designation. If the product says “HEPA-like” or “HEPA-style” filtration, I do not recommend purchasing that.  (Alternatively, the Molekule air purifier foregoes HEPA filtration, in favor of its PECO technology.) 

HEPA filters, however, do not remove odors, gases, so you also want an additional carbon filter. Some companies provide specific filters based on goals and needs (which is something I love about Alen.) 

You also want to evaluate CADR ratings, which stands for “clean air delivery rating,” and is on a scale of 0 – 450, depending on the particle measured. CADR describes the volume of clean air that an air purifier produces when functioning at its highest speed. Higher CADR ratings indicate faster, more efficient air purifiers. When it comes to actually filtering the air, experts recommend at least four air changes per hour for optimal removal of airborne particles. 

That said, Alen doesn’t have a CADR rating, which they propose is biased towards air purifiers which may circulate a higher rate of semi-clean air, rather than a lower rate of cleaner air. They advocate looking at higher filtration efficiency, rather than CADR, and propose that many manufactures “have designed their air purifiers to circulate a lot of air quickly, filtering only the larger contaminants…. [meaning] companies who compete based on their CADR usually do not have other filter offerings other than standard HEPA filtration. Adding filter options with carbon, odor removal or silver-ion technology will reduce their air purifiers’ CADR score, making them less competitive with other lower-end units.” They also state that “CADR also fails to indicate a product's ability to capture and remove bad odors, bacteria, or volatile organic compounds (VOCs).”

That said, I believe there is value to evaluating both CADR, as well as filter efficiency, and a high CADR rating plus added filters for odors, bacteria, VOCs, etc. would address Alen’s concerns. AirDoctor does provide carbon and VOC filter options, and has been tested to remove bacteria and viruses. (I’m uncertain about Alen’s primary motive in forgoing a CADR rating. I’m thinking it’s probably that their units would receive a lower, misleading CADR rating. Either way, I know that both AirDoctor and Alen perform optimally for me.)

How Does AirDoctor Work?

AirDoctor excels at capturing contaminants (both large and small) and filtering the air in the room. The AirDoctor units utilize a three-stage filtration process: a pre-filter, a carbon/VOC filter, and an UltraHEPA® filter, which can capture airborne particles 100x smaller than typical HEPA filters - 0.003 microns! In laboratory tests in an air chamber, the AirDoctor 3000 removed 99.99% of viruses and bacteria, including H1N1 (Swine flu), and 99.97% of the live SARS-CoV-2 virus from the air.  

AirDoctor purifiers also clean the air in a room every 15 minutes (fulfilling the aforementioned 4x per hour quota) using a WhisperJet fan.

My AirDoctor Experience 

I’ve researched and tried a lot of different air purifier brands, and AirDoctor holds it own, with one of the highest CADR ratings: 152- 534 depending on the size (my AirDoctor300 ranks at 340), compared to Molekule’s 330, and Alen’s foregoing of the rating altogether, as discussed above. AirDoctor’s UltraHEPA filtration is one of the best in the industry, with an additional carbon filter to handle VOCs and gases. 

My AirDoctor3000 is relatively quiet. I can barely hear it at all on the first two settings, as well as for the majority of the time in Auto mode. The third setting is a little louder, and the 4th setting is probably too loud for me to run continuously. 

And the Auto mode definitely works! The other day, my hot water heater started emitting a burning/gaseous smell. My AirDoctor immediately kicked into high-speed mode. It knows!!

Subjectively, I have noticed a change in the air. I even thought to myself the other day “wow it feels clean in here,” and that was before remembering I had set up my new AirDoctor. A lingering smell from my Aerogarden cucumber plants also dissipated, after adding AirDoctor. Interestingly, the air condition sensors on my Alens have switched more frequently to blue, indicating to me my AirDoctor is having an effect. 

Ironically, a huge selling point for me with AirDoctor, is something many may see as a downside: AirDoctor does not connect to Bluetooth or wifi. I love this so much! I’m all about reducing EMF exposure (I’m even currently developing an EMF shielding product line!), and I wanted a high end, but low EMF air purifier. (Unfortunately, my Alens and Molekule provide Bluetooth connectivity.)

Noise Level

A noise rating around 50 decibels roughly equals that of a refrigerator; all AirDoctor units range between 30 – 59 decibels, depending on the fan speed. At their lowest setting, they sit at 30-35 decibels. On the first and second setting, I find my AirDoctor3000 to be extremely quiet. Its fan creates a low humming, white noise-esque sound.

As mentioned, AirDoctor’s Auto mode will temporarily switch to high if it detects an increased level of contaminants, then adjust back to the lowest fan setting once the air is cleaned. If the fan speed is medium to high for multiple days in a row, and the filters are more than 6 months old, the filter may need to be vacuumed or replaced. That said, AirDoctor comes with a “Replace Filter” light.


AirDoctor PROS

  • True HEPA filtration with additional carbon/VOC filter
  • High CADR ratings in comparison to other top brands 
  • Has a dim mode to turn off ALL (We cannot have blue light messing up our circadian rhythm!) 
  • Low EMF, with no wi-fi or Bluetooth like other purifiers (including my Alens and Molecule) 
  • Has Auto mode which automatically adjusts the fan speed according to the contaminants in the air. 
  • Very quiet on the lowest setting, and quiet on the second lowest.
  • If you have kids, the buttons can be locked.
  • Filters are easy to purchase together.
  • Has an easy “replace filter” light (Alen has this as well. Molekule does not, and instead requires the app.)
  • Good customer service
  • Much cheaper than other high quality air purifiers, AND you can get $300 off at

AirDoctor Cons

  • Standard, simple design: It’s nothing alienating, but there are no color customizing options like Alen, or super sleek futuristic look like Molekule.
  • The fan is loud on the highest setting. However, this is temporary, and only occurs if selected, or when the air has a higher level of contaminants on Auto mode
  • Standard 1-year warranty (I’d prefer lifetime, like Alen. Interestingly, Alen used to only have a lifetime warranty as long as you ordered filters each year, but now the warranty is lifetime. Molekule features a 2 year limited warranty.) 

Which Size/ How Many?

Your perfect air purifier depends on the size of the room. In general, if there’s a doorway, you will need a new air purifier in that room. If you’re deciding between two sizes, I like to always err on the side of larger (better safe than sorry!) 

In the ideal scenario, you’d have an air purifier for every room. That said, start with where you’re at! If you have to choose just one room, prioritize the bedroom, since this is likely where you spend the majority of your time, and also is when your body is undergoing many detox processes. Next, get one for the room you hang out in most. (You could also pretty easily move the air purifier – at least the 3000 that I have – between your bedroom and living room or office. Picking up things is great exercise!)

When it comes to AirDoctor….

  • AirDoctor 1000: good for bedrooms, offices, and smaller spaces
  • Air Doctor 3000: good for studios, offices, master bedrooms, kitchens, and living spaces
  • Air Doctor 5000: good for 1-bedroom apartments, larger living spaces, open concept areas, and garages


Where to Buy (Up to 50% off!)

I recommend purchasing direct from the manufacturer for the best price and customer service. This is what I do with my Alens as well. You can easily register your AirDoctor, and also immediately purchase filters with your order.

You can get a HUGE discount on each size, including up to $300 off (almost 50% off!), at (The discount will be auto applied at that link)


So What Does It All Mean?

I honestly was very happy with my Alens, but ultimately chose to include an AirDoctor in my clean air arsenal, in part to see if this would be a more affordable, and comparable if not better option, for my myself and my audience. 

I’m happy to say, AirDoctor has truly delivered, and I can confidently recommend it!

It’s UltraHEPA filtration is some of the best industry-wide. It’s quiet and effective. It has no WiFi integeation, and a dim option. And it has my air feeling crisp and clean. If you’re looking for an incredible, affordable air purifier, get Air Doctor now!

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Cancers of the lung, head and neck on the rise: perspectives on the genotoxicity of air pollution 

Assessing Human Exposure to Organic Pollutants in the Indoor Environment

The unsteady state and inertia of chemical regulation under the US Toxic Substances Control

ActIndoor Air Pollution, Related Human Diseases, and Recent Trends in the Control and Improvement of Indoor Air Quality

Environmental and Health Impacts of Air Pollution: A Review




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