The second reason is, all purification technology have drawbacks; some minor and some major. The major drawback with certain purification technologies is the emission of ozone gas. It is harmful when inhaled and also negatively affects the health of the user. While ozone is desirable in our stratosphere, it is a major lung irritant when it’s present in our atmosphere. Therefore, you would want to avoid buying ozone-producing purifiers.
So, how do air purifiers work ?
Basically, there are several types of filtration methods employed by these purifiers:
Types of Air Filtration
#1 : HEPA filtration technology
An air purifier has a filter which arrests airborne particles which are bigger than the size of the pores in the filter. A specific type of filter called High-Efficiency Particulate Air (HEPA) filters are capable in capturing airborne particles bigger than 0.3 microns and in many cases are also effective in removing particles down to 0.01 micron, for instance: mold spores, pollen, bacteria, or others. The only particle it cannot remove is gas, including odor-causing gases and smoke. Therefore, if you also want to remove smoke or a particular gas from the air, it is important to get a home purifier which has a filter designed to capture gas molecules as well. (activated carbon or chemical).
HEPA filters are one type of home air purifier system commonly used in both HEPA purifiers and as furnace filters. They are quite expensive. But its life can be prolonged by the use of a prefilter which is placed such that the air passes through a prefilter before it passes a HEPA filter. That way, coarse particles are removed first by a prefilter, enabling HEPA filter to deal only with cleaner air.
#2 : Activated Carbon Filtration
Chemical and carbon air purifier are types of purifiers which employ carbon and/or chemicals to filter gas, smoke and odor. As you might know, one of the biggest reason why someone wants to buy an air cleaner is to get rid of smoke, bad odor, and harmful gases.
Gas or smoke air purifiers work by incorporating activated carbon as gas or smoke absorbant. Basically, activated carbon is a porous material which can absorb smoke and gasses. However, in order for it to make any difference, the amount of carbon should be at least 5 lb.
This home air purifier system is used as an add-on, so you won’t find any purifier which has this technology alone. Thus, after big particulates are removed by prefilter or other filtration systems, clean air is then passed through activated carbon which removes small molecular weight particulates
Although carbon is effective against semi-volatile organic compounds, it is not effective in removing inorganic gases and formaldehyde. So, if you need to remove these compounds, you will have to get an air purifier which also contains certain chemicals designed to capture those compounds.
#3 : Ionic air purification
Ionic purifiers work by emitting negative ions which then adhere to airborne particles. The negatively-charged particulates are subsequently attracted and captured by various methods, depending on the type of ionizer.
The ionic air purifier is called known as an ionizer and its task is to simply ionize the airborne particles. It is assumed that the ionized particulates will fall down because of the weight and then can be removed easily by a vacuum cleaner.
Other ionic air purifiers known as electrostatic purifiers attract the negatively-charged particulates to positively-charged collection plate in the air cleaner. Many people are attracted to an electrostatic purifier because it is quiet and is totally filterless. However, you will need to wash the collector plate regularly in order for the machine to work effectively. A variation of this kind of purifier has a disposable electrostatic disposable filter (media-filter) instead of a washable collection plate.
With ionic purifiers, it is important to mention that purifiers which utilize this technology have raised some concerns because they emit a small amount of ozone. Ozone, while it protects us from the sun in the upper atmosphere, is not actually good for our health when it presents in our surrounding. It irritates lung and can therefore, make asthma or lung problem even worse.
#4 : Ozone generator
Ozone generators work by producing large amounts of ozone, a strong oxidant gas which can oxidize many other chemicals. Originally, ozone generators are used in restoration and hospitality industry and are only used in unoccupied rooms. However, it has somehow made its way into the air cleaning domain. While the manufacturers try to convince public on the effectiveness and safety of this purification system, EPA remains doubtful of these manufacturers’ claims.
#5 : Ultraviolet air purifier
UV purifiers work by producing ultraviolet light. Like activated carbon, ultraviolet light is usually an add-on to an existing home air purification system and the primary purpose of the UV light presence is to kill off virus and bacteria.