It is not always an easy task to keep indoor air free from pollutants, especially, when Nitrogen Dioxide (NO2) is present in indoor environments. In most cases, there is little you can do to eliminate NO2 and other gases like Sulphur Dioxide (SO2), Formaldehyde (TVOC), or even pathogens like H1N1 Influenza A virus (pandemic flu), and Staphylococcus aureus (or similar bacteria).

Here comes the HA500 Air Purifier by Healthy Air Technology which is able to eliminate all of these pollutants/pathogens from indoor environments. It does that thanks to the triple-layered system with a primary filter, HEPA 13 filter, and Pollution Eraser DNO filter. DNO means D-Orbital Nano Oxide which is made of two parts. 

1st part: The Carrier – Activated charcoal. The material that is used in military gas masks, and captures pollutants within the pores of the charcoal.
2nd part: The Transition metal oxides – Transition metal oxides are coated in the activated charcoal to form catalysts, and these catalysts break down pollutants and toxic gases into harmless chemicals and then release these harmless materials back into the atmosphere like water, oxygen, carbon dioxide, etc. The DNO is invented by the founding CTO of Oxford Catalyst plc (a leader in novel industrial catalysts).

HA500 Control Panel and Display


  • CADR: 500 m3/hr or 300CFM.
  • Applied Space: Max 80 m2 or 861 ft2
  • Sensors:
    • PM2.5 (Laser Light Scattering)
    • Light Sensor
  • Display: LED Digital Display
  • Motor: DC motor
  • Power Consumption: 4~45 watt (max)
  • Noise: 34 ~ 64dB
  • WiFi: IEEE 802.11 b/g/n
  • Size: 29 x 29 x 56 cm
  • Weight: 8.48 kg
  • IR Remote Control

Power Consumption

Appliances that have a low energy footprint are important if we want to keep our electrical bill low. The power consumption ranges from 4W to 43.5W. My estimated annual electricity cost for running the purifier 365/24/7 in auto mode is about 7.88€. I think it’s worth it!

  • Sleep Mode: 4W
  • Speed 1: 5.5W
  • Speed 2: 11W
  • Speed 3: 18W
  • Speed 4: 24W
  • Speed 5: 43.5W
HA500 in Standby Mode


These are the five levels of noise for the five-speed manual gears. The Sound-level Meter was at a one-meter distance from the purifier. Keep in mind, different rooms can give different results. Also, I included the characterization of the sound levels.

  • Speed 1: 31.1dB (soft whisper)
  • Speed 2: 39.7dB (quiet office)
  • Speed 3: 44.7dB (quiet office)
  • Speed 4: 47.3dB (quiet office)
  • Speed 5: 51dB (normal conversation)

Filtration Performance

Particulate Matter PM2.5 reduction happens almost instantly which means after a few minutes the purifier can capture all PMx pollutants thanks to the HEPA H13 filter. Another reason for its effectiveness is the dual HEPA filtration system. One on the left and another one on the right of the purifier. More air passes through the purifier, as a result, more air is treated quicker.

HA500 Filters

The DNO catalyst integrated into the HA500 was tested for various indoor air pollutants in an independent certified lab. It takes more time to remove NO2 and other gases like pollutants but this is normal due to the physical properties of the gases.

Anti-virus (H1N1) properties tested in 2020 by third party in 30 M3 lab, initial concentration is 3.59*10^6 cfu/m^3 cfu/m3 * SO2 and NO2 are tested in 2020 by third party in 30 M3 lab in 0.5 – 3 hours.

Healthy Air Technology has included negative ions (NIAPs) in the system: Firstly, to achieve better removal of particles. However, although negative ion generators also generate ozone as a by-product, the core technology DNO catalyst can convert ozone to oxygen, so there is no secondary pollution for including it. Finally, for health benefits, read more here. You can always turn the negative ion generator off.

My Experience

I live next to a dead-end road, which means not many cars pass by, but this is not the case because many drivers use the dead-end as a turnaround, and I hate it! They create a lot of noise and pollution especially when they keep the engines idling. NO2 is present in high concentration in rush hours, and I always keep my house closed during peak hours. However, pollutants are sneaky, and they enter my apartment.

This review took a lot of time to complete because I did a lot of experiments to make sure that the advertising claims are true. Gas wise the purifier can reduce the NO2 concentrations by 50% in about 1 hour. Keep in mind, real-life pollution reduction is different from lab pollution reduction because in a lab they stop supplying the chamber with the pollutant but in real-life vehicles are constantly producing NO2.

Particulate matter disappears from my bedroom where I have the air cleaner running. It is a bit noisy even with the night mode activated but, in my defense, I need absolute silence to sleep.

Even with the negative ions enabled, the ozone monitors don’t detect an increase of the O3 gas during extended hours.

At the moment, the company hasn’t finished with the development of the smartphone app, so I can’t present it. The air cleaner is equipped with the technology to connect to the cloud and your phone, so stay tuned!


Although when I first heard about the DNOfilter I was skeptical, I decided that it worth my time and my readers time to learn more details about the technology inside the HA500 purifier as NO2 pollution due to Diesel gate vehicles has great impact in our health. The claims are true, it is able to remove NO2 and other gas chemicals from the air. Removing particulate matter from the air is an effortless task for the HA500 purifier.

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