What exactly are Air Purifiers?
Simply put – An air purifier is a machine that thrives to remove contaminants from the air around us.
There can be many techniques employed to purify the air. Most air purifiers use one or more combinations of these techniques and technologies to purify the air around us. Let’s have a look at what are the technologies available to remove these contaminants from air.
UV – (Ultraviolet)
When air passes through UV lamps, it simply sterilizes the air that gets in contact with the UV Lamps. The air if forced through a fan and is cleansed of the dead organism that persist in the air.
It’s very simple. Think of a dust storm and you wearing a fine net. The net filter would remove a lot of particles. Well, we usually don’t have dust storms at homes or at offices but there are very fine particles that are contaminants and we need very fine filters that net won’t be able to remove. Filters in air purifiers do precisely the same job of removing these very small particles and contaminants from air.
Very fine filters are known as HEPA filters or High-efficiency particulate arrestance filters. These HEPA filters are able to remove up to 99.97% of 0.3-micrometer particles. .3 micrometer is the size of the contaminant particle.
Many air purifiers employ pre-filters. Pre-filters can only catch larger particles. Ideally, one does not need a pre-filter if a HEPA filter is present. However, Pre-filters do a good job of increasing the life of HEPA filters that relatively cost more than pre-filters.
Activated Carbon –
Gas can pass through a net and there are harmful gases in the environment. Activated Carbon through absorption convert these gases into solids. These solids are later on captured by filters. Hence most of the times Activated carbon is used in conjunction with filter technologies.
There are chances that you would have seen balloons sticking to walls and ceilings. If you haven’t, just rub an air balloon against your hair and try sticking it to the wall.
Using a similar principle, small electric currents are passed through a media that creates a magnetic field. The contaminants become polarized and stick to a disposable or washable fiber media pad. Polarized Media Technology is non-ionizing.
Ionizers produce electrically charged air. These electrically charged air (called ions) stick to the air pollutants which are then attracted to a electrostatic plate. You would see a lot of them being marketed as Anion based air purifiers. Anions are nothing but negatively charged particles while Cations are positively charged particles. Most air purifiers deploy anions. A small downside of Ionizer based purifiers is that they produce small traces of Ozone, although most of them produce below the accepted .05 ppm of Ozone which is an industrial safety standard.
Ozone Generators –
Ozone generators produce Ozone. These are generally used in unoccupied rooms to remove large amount of oxidants. Large amounts of Ozone is toxic in nature. Please use caution if you are buying any Ozone based air purifier.
For more information, see our section – Air Purifiers Filtration Levels.