Office air is not always purified and of the best quality. Also, the health effects of airborne particles are becoming increasingly apparent. There is now good evidence that mortality rises in the range of air particle levels previously thought to be normal and safe. In fact, mortality approximately doubles going from particle level that an air purifier will produce up to one that is still within the EPA’s safe range. Also, there is evidence that thinking ability, cognitive function, is impaired by airborne particles.
So it is perfectly reasonable to consider a desktop air purifier.
Desktop air purifiers are smaller and less powerful than standard air purifiers and are often not able to purify the air in a room larger than 80 square feet (with 8 foot ceilings), So unless you have a small room and can tolerate the noise of them being on the top fan speed they are not going to be suitable for your room. However, they can still be useful if the purified air is directed at your nose and mouth.
The IQair Atem is the best desktop air purifier. It has a HEPA filter which is specified to filter ultrafine particles down to a size of 0.03 micrometres in diameter. It also has a mechanism for focusing the purified air in the region of your mouth and nose so that you only breathe purified air.
What is a Desktop Air Purifier?
A desktop air purifier is one that has been specifically designed to sit on a desktop or bedside cabinet and ideally has a specific mechanism for directing the airflow to the area of the mouth and nose of the person sitting at the desk. In contrast, most floor-standing air purifiers have the air outlet pointing up to the ceiling.
Why Have a Desktop Air Purifier?
On the whole the main reason is to purify your own air that you breathe. In a space like an office you cannot alter the conditions for the whole office but it may be possible to use a personal air purifier.
Do desktop air purifiers work?
As a general rule desktop air purifiers work very well in the sense that the air coming out of them is filtered to a true HEPA standard. To work in the sense of improving your health the air purifier must have a mechanism for getting that purified air to the region of your mouth and nose so that you can breathe it in before the air is dissipated into the room. Once the air is dissipated into the room, there is usually so much unpurified air that the effect of the air purifier on improving air quality is minimal.
Desktop Air Purifiers-noise is a potential problem
There are 2 potential problems with noise-
- You will need to be within about 16 inches of the desk air purifier for the jet of air to reach you before it has mixed too much with the dirtier room air and become contaminated.
- In a shared office noise, is a potential problem for your co-workers as no one wants to be near a noisy machine. So ideally you need to know how noisy a machine is on each fan speed before you buy it. You also need to know which fan speed that you are likely to need to use. So you need quite a lot of data from the manufacturer.
If you are thinking of getting a desktop air purifier for a home office, you are probably better getting a normal air purifier and purifying all the air in the room. The air purifier will be further away in the room and seem quieter. I have written an article about how to buy an air purifier “Buying an Air Purifier“.
Specifications in Looking for the Best Desktop Air Purifier
1) True HEPA Filter
To remove airborne particles, which are usually the most important air pollutant, a true HEPA filter is necessary. It is the standard for an air filter and will remove these particles-
- House dust mite
- Pet dander
- Pollen
- Mold Spores
- Dust-household and atmospheric
- Bacteria
- Viruses
- Brake dust
- Tire dust
- Vehicle exhaust particles
- Smoke particles both cigarette and wildfire
2)Activated Carbon Filter
A HEPA filter will catch very small particles but it cannot catch airborne contaminants the size of molecules. An activated carbon filter will adsorb molecules such as volatile organic compounds. These gaseous pollutants come into contact with the surface of the activated carbon, which then keeps the pollutant chemicals attached to the surface with weak intermolecular bonds. By removing gaseous pollutants, air purifiers with activated carbon filters can improve odor and hence indoor air, sometimes dramatically.
UV light, and an ionizer are not needed as they are not very helpful. An ozone generator should not be part of a desktop air purifier as ozone can irritate the lungs.
Both the particles and volatile organic compounds are removed from the room permanently when the filters are dispose of an a replacement filter installed.
1) Designed to Focus Air in the Direction of Your Mouth and Nose
iQair Atem
Overall
This desktop air purifier’s elegant design and clever air focusing mechanism are the standout features.
Health Aspects
The Atem’s filter is specified to remove 99.5% particles greater than 0.003 micrometres in diameter. This means that a significant amount of the ultrafine particles, small enough to enter the bloodstream will be removed. These ultrafine particles have been linked to premature death and heart attacks. I have written an article about the health effects of ultrafine particles, “Airborne Ultrafine Particles-do they accelerate aging?“
| CADR (cfm) | Suitable for Room Size (sq ft) | Noise on Top Fan Speed (db) | |
| iQair Atem | 18 | 28 | 44 |
| Dyson Pure Cool Me | Not given | Cannot Calculate | Not Given |
Dyson Pure Cool Me
Overall
An elegant design and clever air focusing mechanism are the standout features of this desktop air purifier.
Health Aspects
The filter is specified to remove 99.95% of the ultrafine particles when tested for filtration efficiency at 0.1 micrometres. Particles of 0.1 micrometres of the largest ultrafine particles and will not enter the bloodstream as easily as smaller particles. One study showed that 0.04 micrometre ultrafine particles enter the bloodstream and much higher numbers than 0.34 micrometre particles. So it is good to know that the filter is good at removing 0.1 micrometer particles but it would be even better to know how it did with particles 20 times smaller.
Like all desktop air purifiers both these machines are not designed to purify the air in the whole room. Rather they deliver a concentrated jet of purified air to your mouth and nose for you to breathe in. This means that you need to be fairly close to the air purifier as the air soon mixes with dirty air in the room/office.
This is a great approach but not every manufacturer takes this approach as we will see in this next section –
2) No Design Feature to Angle Purified Air Towards Your Mouth or Nose-purified air leaving the air cleaner points straight forward
a) Purified Air Is Not Directed at Your Mouth and Nose
If the jet of air there is not directed at your mouth and nose then you will receive virtually no benefit from the air purifier. The reason is that any jet of air mixes almost immediately with the room air. These air purifiers cannot powerful enough to make an appreciable difference on the quality of the room air. Unless the room is tiny, for instance 8′ x 10′.
| CADR (cfm) | Suitable for Room Size (sq ft) | Noise on Top Fan Speed (db) | |
| Germguardian AC4100 | 50 | 78 | 50 |
| Levoit LV-H126 | 50 | 78 | 52 |
You could get around the a lack of directional nozzle by propping these air purifiers up somehow so that the airflow from the outlet points at your mouth and nose. However if they have a diffuser breaking up the jet of air leaving the air purifier this will not work-
b) Any Diffuser is a Problem
These air purifiers have a diffuser of some kind, either a cloth front piece to deflect the air more sideways like the Germguardian AC4100. Or in the case of the Levoit LV-H126 a plastic grill with holes to break up the jet. My experiments show that it is difficult enough without a diffuser or deflector to keep the high air quality of the jet of air that reaches the mouth or nose. This is because as room air starts mixing with the air coming out of the air purifier.
So deflecting a good part of the air sideways as in the Germ Guardian or breaking up the jet as in the Levoit will only make it more difficult for a pure jet aware to get directly to the mouth and nose.
3)Purified Air Jet Points Away From You or Straight Up
The most difficult combination is the air purifier that is too small to purify the air in the whole room and also does not direct purified air even in the direction of the user. Sometimes the air comes out of the back of the air purifier. In this case, all you can do is turn the air purifier around so that it is back to front and point the jet of air at your mouth and nose.
Possibly the cheapest option would be to buy a small room air purifier such as a Levoit 200S then rest it on something or make a stand so that it points at your mouth and nose. It would also be much quieter, about half as quiet as some purpose-built desktop air purifiers. It would however lack a nozzle to focus the air to your mouth and nose. You may find that you do not need a nozzle or be able to construct one with tape and paper.
Do air purifiers work in cubicles?
As a general rule, a personal air purifier in an office cubicle will only work if the jet of purified air is pointing at your mouth and nose. This will then allow you to breathe in purified air rather than the general office air. Even then, my own experimental measurements show that the further you are from the air purifier, the more office air manages to mix with and make the purified jet of air “dirty”.
In my measurements, by the time I was 16 inches from the air purifier, the mixture was 50/50. So the jet of air from the air purifier becomes “dirty” quite quickly with distance from the origin of the jet although this will depend on the velocity of the jet.
Test That Your Air Purifier is Working With a Particle Counter-Most Important of All
The most important thing is to test the desktop air purifier effectiveness using a particle meter. I have written an article about particle counters some can be as cheap as $25, “How to Test Air Quality in Your Home“.
To do this take a reading of the particle count of the office air where your desk is, with the air purifier is switched off. Then switch the air purifier on and take a particle count by your mouth and nose when you are sitting in the position that you normally work. You could experiment by changing the position of the air jet from the air purifier until you get the maximum reduction in particle count. This should be a reduction of at least 50% and ideally somewhere near 80%.
Conclusion
Desktop air purifiers are certainly a viable option for giving you purified air. These can be useful where you have no control over the general air purification, such as in an office. They must point the jet of air at your mouth and nose to be effective. Otherwise, the purified air will simply mix with the room air and have no effect for you.
However, if you have a home office or bedroom, you would be much better using a standard air purifier that is properly sized for the room. This is because desktop air purifiers giving very small area of purified air in which her mouth and nose need to stay to breathing clean air. In contrast, a standard air purifier will purify all the air in the room.
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