Working Principle of Air Purifier

Air Purifier

Air purifiers are the devices that are used to sanitize air by eliminating dust particles, pathogens, bacteria, and other pollutants. The working of an air purifier is quite different from the air filters because an air purifier tends to filter the pollutants as well as sanitize the air; whereas, an air filter only focuses on the elimination of contaminants. Unlike humidifiers and diffusers, air purifiers do not add particles to the environment but instead remove germs, dust, and pollution-causing particles.¬†Plants and trees take gases that are toxic, harmful, and unfit for human consumption such as carbon dioxide and release oxygen into the environment, hence they are known as nature’s air purifiers.¬†An air purifier typically acts as a sieve that traps the impurity particles and allows pure air to circulate through the room.

Working Principle of Air Purifier

There are a variety of air purifiers available in the market that use distinct methods to sanitize the air present in the surroundings. Some of them circulate the air through the filters and capture the impurity particles, while some of them directly purify the air without filtering. The most common methods used by air purifiers for sanitization of air are listed below:

Purification with the help of HEPA Filters

When the dust or germ particles enter the water vapour molecules present in the air, the particulate matter gets formed. On the basis of the size or the diameter of the particle, particulate matter present in the air can be classified into two categories, namely 2.5 micrometres particulate matter and 10 micrometres particulate matter. The small size of the particulate matter facilitates them to travel freely through the air without any barrier. Particulate matter has severe long term harmful side effects on the health of a person. When a person inhales the air that contains particulate matter and other impurities, the particles of particulate matter get stuck into the pores of his/her lungs. Further, there are chances that the particle might get dissolved into the blood, thereby increasing the possibility of developing chronic breathing disorders such as asthma, sinusitis, breathlessness, etc. The main purpose of air purifiers is to restrict the flow of such particulate matter into the environment. For this purpose, most air purifiers make use of HEPA filters. A HEPA filter or a high-efficiency particulate air filter is capable of disabling the free propagation of particulate matter in the air that is over 0.3 micrometres in size. About 99.97% of the purification of air can be achieved easily with the help of a HEPA filter. The impure air enters the filter through one side and pure air is obtained from the other side. This process of passing the impure air through the filter is performed at a relatively high speed, thereby enabling quick purification. The impurities get stick to the filter face, which is why the filter needs to be replaced frequently depending on the air quality index of the surroundings.

Purification with the help of Neutralization

Some of the air purifiers sanitize the environment by directly neutralizing the particles present in the air without any pre-filtering. The neutralization of the particles present in the air occurs when the air purifier constantly emits negatively charged particles into the air. The negatively charged particles help the purifier capture the positively charged ions or the impurity particles that are already present in the air. The only reason why such types of air purifiers are usually not preferred is that they are most likely to cause ozone emissions.

Purification with the help of Ionization

Ionisation is yet another simple process that is used by air purifiers to eliminate the impurity particles present in the air and sanitize the surroundings. An ion is basically a charged particle and ionisation is the process of assigning a charge to a neutral element. The air purifiers that make use of the ionization process for the purpose of sanitization and purification initially supply charge to the neutral air particles. A metal plate that is charged with opposite polarity is then made to pass through the air. The charged air particles; therefore, get attracted towards the metal plate that is charged with opposite polarity and get deposited on it, thereby purifying the air.

Purification with the help of Ultraviolet Light Rays

There are certain air purifiers available in the market that make use of ultraviolet light radiations to purify the environment. Ultraviolet light radiations are capable of disinfecting the environment by terminating the growth of microorganisms present in the air. Generally, ultraviolet radiations equipped air purifiers are used in biology laboratories, semiconductor labs, optical fibre fabrication industries, etc.

Purification with the help of Absorbents

Certain air purifiers make use of absorbents such as charcoal activators etc. The absorbents tend to trap the impurity particles with ease and create a clean and sterile environment.

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