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News18 » Tech
5-min read

Why Dyson Air Purifiers Are Smarter Than Most: Better Filters And Smarter Testing

Dyson’s premium air purifiers take advantage of the new POLAR testing method to better tune the efficiency of their purifiers.

Vishal Mathur | @vishalmathur85

Updated:October 14, 2019, 1:12 PM IST
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Why Dyson Air Purifiers Are Smarter Than Most: Better Filters And Smarter Testing
Dyson’s premium air purifiers take advantage of the new POLAR testing method to better tune the efficiency of their purifiers.

The air purifier that you must buy for your home, if you already haven’t, is no longer a luxury item. In fact, the frankly atrocious air quality in most of our cities makes the air inside our homes also quite deadly. And it will become worse in the coming days, with the smoke from the stubble burning in neighbouring states adding to the problem which is already compounded by the reducing air temperatures which keep a layer of haze close to the surface. Which makes these devices all the more essential in our homes. But herein lies the biggest challenge, to convince potential buyers that they need one for their home. After all, what cannot be seen isn’t a threat, in the opinion of many. Air pollution, be it indoor or outdoor, doesn’t have a physical form that you can see or touch. Yet, what we perhaps don’t realize is that each day we breathe between 9,000-11,000 litres of air—and surely a lot of that would be indoors, either in home or at work. Basically, air pollution is not going to abuse you, threaten you with a weapon, try to take away your prized possessions or punch you in the face. It is a silent and unseen enemy, chipping away at your immune system, at your health and well-being. An air purifier is what helps you fight this unseen enemy inside your home, by running the air through multiple sets of filters.

British technology company Dyson is doing things a bit differently though. They already have a rather elaborate range of air purifiers in India, and these aren’t tested and rated in the same way as a lot of other air purifiers that you may find in shops or for sale on online stores. Most air purifiers tend to rely on a stat called the Clean Air Delivery Rate (CADR) to establish their air cleaning capability prowess. Dyson on the other hand has something they call the POLAR test, which they say is more in tune with the real-world usage conditions, particularly in India.

The very foundation of the POLAR test is a lab, which is essentially a room, that is 27 square meter (around 290 sq. ft) in size. There is no added ceiling fan in the room. That is sound logic, since the peak pollution season in India is winter and we don’t use fans at that time of the year. as part of this test, the air purifier in question is placed in one corner of the room, pretty much how you would probably keep it in your living room or bedroom. The pollutants are then added into the room from the other corner, which is perhaps the toughest test of strength for an air purifier. There are nine air quality sensors places in all corners of the room including one sensor in the centre, to understand the exact air quality in the different parts of the room at all times. These sensors can detect particles as much 300 times smaller than a strand of human hair. Another important element of this test is the auto mode—all purifiers are tested at the automatic settings, first with the assumption that the user wouldn’t want to interfere and secondly to check as to how good the automatic air quality detection of the purifier itself is. Dyson believes that this provides a better assessment of the cleaning prowess of an indoor air purifier, and how effective it will be in indoor situations in the real world.

Also Read | Dyson Pure Hot + Cool Review: The Brilliant Air Purifier Adds a Cool Quotient With Heating

What the Dyson POLAR test counters is the CADR test, that has been around since the 1980s. This is done in a much smaller 12 sq. meter room, and the purifier is kept in the middle of the room. It is then run for 20 minutes. There is one air quality sensor in the room to detect the change in pollution levels. Interestingly, this test is also done with a ceiling fan helping the spread of clean air around the room. The challenge however is that this isn’t exactly representative of the real-world environment—we do not keep purifiers in the middle of the room, is it? After this test, purifiers are given a rating. But the point is, an air purifier with a high CADR rating is not a true indicator of whether it may be cleaning air and removing even the smallest particles from the indoor air.

This is where the quality of the filters inside an air purifier becomes important. What is a point of an air purifier if the filter sucks in air and simply throw out the smallest of pollutants and particles back into the room?

Also Read | Dyson Pure Cool Me Review: The Clean Air You Should Have, And The Peace of Mind Which Follows

The filter in the Dyson Pure Cool Link air purifier is a single unit that integrates the glass HEPA and the tris-coated activated graphite layers. Dyson have changed that around in the Pure Cool, the Pure Hot+Cool and the Pure Cool Me to a filter set that is split into separate layers of the glass HEPA and activated carbon filter. Yet when they are installed inside the purifier, they are sealed together in a way that no dust or particles escape. The very fine pre-filter layer that traps the larger particles before the air passes through the HEPA filter. These filters can capture particles as small as 0.1 microns—these are 100 times smaller than the human hair. The 0.1-micron particles not only go into the lungs but can also enter the bloodstream. Most HEPA filters can capture particles as small as 0.3 micron only.

The list of the pollutant types that fall before these filters is quite long—dust, pollen, tobacco smoke, pet allergens, dust mite allergens, 2.5 micron particles, 0.1 microns particles, tobacco smoke, Formaldehyde, Benzene, Ammonia, Acetaldehyde, Acetic acid, Ozone, Nitrogen dioxide, Toluene, Trichloroethylene and Naphthalene. The activated carbon layer can absorb gases, odors and volatile organic compounds in the room faster than before, and for longer. We tested this in a 20 sq. m size room, and the Dyson Pure Cool improved the air quality from a very unhealthy 98g/m3 of PM 2.5 to a much healthier 14g/m3 in 15 minutes-data verified by a third-party air quality monitor placed in the opposite corner of the same room.

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