Most Popular Air Purifiers Technologies

The most important components of air purifier are its air filters or media. Indeed, most air purifiers  contain at least two air filters. Some use three or four different air filters. One of the easiest ways to find the right air purifier is by looking for models that have specific types of filters. To do that, learn about the main characteristics of today's most popular air filters technologies.
Different air purifier filters target different types of air pollution. HEPA air purifiers are the most popular, and they are perfect for eliminating household allergens such as dust, animal dander, and pollen, but they are not very good at capturing ultra-fine particles like viruses or eliminating foul odors, organic compounds, or chemical fumes.Because different air purifier technologies have different strengths and                   weaknesses, many modern air purifiers combine two or more filter or media types in the same unit. For example, the best-sellers  Austin Air Healthmate utilizes a HEPA filter along with a thick bed of activated carbon to help eliminate dust and odors.  With that being said, let's take a closer look at the different types of filters:

1. HEPA filters remove at most 99.97% of 0.3-micrometer particles, and are usually more effective for particles which are larger. HEPA purifiers which filter all the air going into a clean room must be arranged so that no air bypasses the

HEPA filter. In dusty environments, a HEPA filter may follow an easily cleaned conventional filter (pre-filter) which removes coarser impurities so that the HEPA filter needs cleaning or replacing less frequently.
HEPA material looks like a very thin bail of fibers. Air has to find a route through this maze of fibers, and there are three steps in the HEPA filter process of trapping particulates. First, a particle runs into the fiber and sticks. Then, the particle gets within one diameter of a fiber in the HEPA air purifier; while it tries to get by the fiber it becomes stuck to the fiber. Finally, as a very small particle (about 0.1 micron) moves in the gas flow, it dithers about due to collisions with molecules (Brownian motion); the particle slides close to the fiber and becomes caught. This is how HEPA air purifiers stop mold spores, as well as many bacteria, viruses, and dust.
HEPA filters do not generate ozone or harmful byproducts.

2.An electrostatic precipitators air purifier is very similar to HEPA air purifiers, except they do not use air filters.  Electrostatic precipitators use electronic cells to charge particles within the purifier and immediately the charged particles stick to the sides of the internal filtration system on collector plates, but only about 30% of particles are removed from your indoor air. 

The main advantage with this type of air purifier is that the collector plates never have to be replaced; they can be easily washed in the dishwasher. Be aware that some electrostatic precipitators also generate ozone
Charged Media Filters work the same way as electrostatic precipitators, but they collect particles on fiber filters instead of plates. The advantage of these filters is that they are able to collect very small particles, sometimes as small as 0.1 microns, through a combination of a filter and an electrostatic charge. The disadvantage is that, like the electrostatic precipitator filters, charged media filters lose their efficiency fairly quickly, and they can require more frequent filter replacements compared to a HEPA air purifier. These types of units can produce ozone, but the better ones on the market do not

3. Ozone generators produce ozone, and are sometimes sold as whole house air cleaners. Unlike ionizers, ozone
generators are designed to produce significant amounts of

ozon generator

ozone, a strong oxidant gas which can oxidize many other chemicals. The only safe use of ozone generators is in unoccupied rooms, utilising "shock treatment" commercial ozone generators that produce over 3000 mg of ozone per hour. Restoration contractors use these types of ozone generators to remove smoke odors after fire damage, musty smells after flooding, mold (including toxic molds), and the stench caused by decaying flesh which cannot be removed by bleach or anything else except for ozone. However, it is not healthy to breathe ozone gas, and one should use extreme caution when buying a room air purifier that also produces ozone.[13]
   
4.Ultraviolet germicidal irradiation- UVGI can be used to sterilize air that passes UV lamps via forced air. Air

purification UVGI systems can be freestanding units with shielded UV lamps that use a fan to force air past the UV light. Other systems are installed in forced air systems so that the circulation for the premises moves micro-organisms past the lamps. Key to this form of sterilization is placement of the UV lamps and a good filtration system to remove the dead micro-organisms.

5.Activated carbon is a porous material that can adsorb

volatile chemicals on a molecular basis, but does not remove larger particles. The adsorption process when using activated carbon must reach equilibrium thus it may be difficult to completely remove contaminants.[5] Activated carbon is merely a process of changing contaminants from a gaseous phase to a solid phase, when aggravated or disturbed contaminants can be regenerated in indoor air sources.[6] It is normally used in conjunction with other filter technology, especially with HEPA.

Read more details :
Carbon-Activated Air Purifier
  6.Pre-Filters remove pet hair and other large particles prior to primary filtration and come with nearly all air purifiers. Most

prefilters are either foam or some sort of non-woven nylon, and some have electrostatic properties to increase filtration. Look for prefilters with activated carbon. This type of prefilter will not only trap large particles but also adsorb odors and smoke. Regularly changing prefilters will increase the life span of your HEPA filter.