Ionic Air Purifiers vs Electrostatic Air Purifiers vs HEPA Air Purifiers
As their name suggests, the main task of air purifiers is the removal of air particles like dust, pollen, pet dander, bacteria, viruses, VOCs (Volatile Organic Compounds), odors, smoke, etc.
Over time, several technologies have been used in air purifiers in order to achieve the best air filtration possible, including ion generators, electrostatic plates, HEPA air filters, etc. Today, modern air purifiers feature air purification systems that combine different technologies allowing them to exhaust practically clean air.
Published: September 6, 2021.
Ionic Air Purifiers
Ionic air purifiers emit negative ions (hence their name) that stick to the passing airborne particles, forcing them to stick to various surfaces.
Such air purifiers can be made fanless and filterless, requiring very little power to operate.
On the other hand, it is very important what surfaces airborne particles stick to - nobody wants mold spores to stick to walls or someone's lungs, for example.
As such, pure ionic air purifiers don't do their job very well, IMHO of course.
Also, as they operate, ionic air purifiers may generate ozone in trace amounts - while ozone is powerful oxidant excellent in removing/destroying tobacco smoke and similar air pollutants, it is also rather harmful to lungs and other soft tissue.
So, if You are looking for a home or room air purifier, classic ionic air purifiers are perhaps not the best choice.
Electrostatic Air Purifiers
Electrostatic air purifiers feature two plates with a strong electric field between them. As the air passes between these two plates, charged air particles will stick to the plate of the opposite charge.
All that user has to do is periodically clean the plates.
Electrostatic air purifiers can be combined with ionic air purifiers - negative ion generator is combined with positive collector plate.
As negative ions stick to the airborne pollutants, they are all collected on the collector plate, improving the air purification level when compared with classic ionic air purifiers.
But, even such air purifiers may emit ozone in trace amounts - again, in rooms and homes ozone may be harmful and is considered as pollution!
HEPA Air Purifiers
HEPA air purifiers feature one or more air filters that capture airborne particles, purifying the air.
The following comparison chart lists several classifications of EPA/HEPA/ULPA filters according to the EN 1822 standard:
|Filter Group||Filter Class||Filtration Efficiency||Penetration|
|Efficiency Particulate Air (EPA) Filters||E10||85 %||15 %|
|E11||95 %||5 %|
|E12||99.5 %||0.5 %|
|High-Efficiency Particulate Air (HEPA) Filters||H13||99.95 %||0.05 %|
|H14||99.995 %||0.005 %|
|Ultra-Low Penetration Air (ULPA) Filters||U15||99.9995 %||0.0005 %|
|U16||99.99995 %||0.00005 %|
|U17||99.999995 %||0.000005 %|
Note: In the European Union air filtration is defined by standard EN 1822, which defines several classes of EPA/HEPA/ULPA air filters according to their ability to retain the Most Penetrating Particle Size (MPPS) particles that are in the 0.1 and 0.3 micrometers range.
Generally, a "true HEPA" air purifier is able to capture at least 99.97% of 0.3 microns or larger particles - the definition of the "true HEPA" air purifier is very similar to the HEPA H13 class.
Modern true HEPA air purifiers combine several air purification methods to achieve the best possible air purification, including:
- mechanical air pre-filter captures large airborne particles and protects the inner air filters from damage.
- activated carbon air filter captures odors, smells, VOCs, etc. Activated carbon air filters are highly recommended for households with pets, smokers, people with asthma and allergies, etc.
- HEPA air filter captures small airborne particles - the size and percentage of capture depend on the HEPA air filter class.
- UV-C lamp combined with Titanium Dioxide (TiO2) sanitizes air killing airborne bacteria and viruses and decomposes various VOCs. While UV-C lamps can be excellent in sanitizing the air, they also may produce some ozone in trace amounts.
- Ionic/electrostatic generator/plate may remove even the smallest airborne particles that pass through the activated carbon/HEPA air filter. But again, ionic/electrostatic air filtration may produce ozone in trace amounts.
Although modern air purifiers with UV-C lamps and ionic/electrostatic generators/plates produce ozone in very small amounts, usually far below the allowed amount, these features can be off to prevent any ozone from being produced.
Personally, if You are looking for a new air purifier, go for the HEPA air purifier with an activated carbon air filter and HEPA air filter. If You like models with UV-C lamps and other similar features, be sure that such features can be turned off. Just in case...