What function of HEPA filters is

What function of HEPA filters is?

HEPA filters

HEPA is an acronym which stands for High -Efficient Particulate Air. This air filters are very good in eliminating both small and big particles of pollutants .This particular filter has the ability of capturing a minimum of 99.97 percent of contaminants as small as 0.3 microns. HEPA filters were originally designed to get rid of radioactive contaminants in the air .They have many applications including being used in; medical facilities, aircrafts and automobiles. Many air purifiers used in homes, are fitted with HEPA filters so as to get rid of allergens such as dust, pollen, mold and even spores. It is for this reason that doctors have recommended the use of an air purifier, which possesses HEPA filters, for people who suffer from asthma or allergies.

How HEPA filters work

HEPA filters work

This air filter is made up of a mat of randomly arranged fibers, which are composed of fiberglass. Factors affecting the efficiency of the HEPA filters include face velocity, fiber diameter and filter thickness. The HEPA filters work by pushing contaminated air through the fine mesh which ends up trapping contaminants like pet dander, pollen, dust mites , and pollen. Basically, the HEPA filters trap the pollutants in four ways and they include;

This kind of mechanism deals with the heavy and large particles which are suspended in the flow stream. These particles turn out to be heavier than the fluid surrounding them .During the fluid flow, the fluid changes its direction and goes into the fiber space ,but due to inertia the heavy particles continue moving in a straight line and they end up colliding with media fibers which trap them.

This second mechanism involves the trapping of small particles of contaminants .The viscous fluid normally doesn’t trap the small particles effectively and hence they end up diffusing within the flow stream .As these particles escape the flow stream they end up colliding with fiber which traps them. This mechanism helps in the trapping of particles even as small as 0.1 microns.

This particular mechanism is ideal for mid- sized particles of contaminants. These particles are not small enough to be trapped through diffusion or large enough to be trapped through inertia impaction. Therefore, the mid- sized particles follow the flow stream and they end up becoming trapped by the fiber as the flow stream bends.

This mechanism is adapted by the HEPA filter if the particles happen to be too large in that they cannot fit between the spaces of fiber.


As we have seen above, HEPA filters have been applied in different devices or machines so as to deal with air contaminants examples being;

Vacuum cleaners

Most of the Vacuum cleaners use HEPA filters in their filtration system. This is important in that it enables them to eliminate allergens such as pollen and dust in the air .These air pollutants trigger asthmatic attacks hence eliminating them saves asthmatic suffers from asthmatic symptoms. Vacuum cleaners are used in vacuuming floors, carpets and even walls.

Air purifiers

Air purifiers are devices that trap contaminants in the air hence cleaning up the air. Many air purifiers use the HEPA filters to do this though some use filter- free mechanisms. Many doctors recommend the use of air purifiers by allergy and asthma sufferers since it helps in relieving them of the symptoms brought by these illnesses.

Biomedical applications

HEPA filters are also used in medical facilities to deal with contaminants. They prevent the spread of airborne and harmful microorganisms like bacteria and viruses. This prevents the spread of infections, for instance within the hospital. It is normally used on patients who have active tuberculosis.

These are some of the applications of the HEPA filters .Other applications may include; used in vehicles and aircrafts. HEPA filters therefore have a great significance in our lives. If your house is normally full of pollutants like dust, it is advisable to purchase air purifiers fitted with HEPA filters.

What function of Ionic purifiers is

What function of Ionic purifiers is?

Ionizing Purifiers

Ionic purifiers, also known as negative ion generators, are common types of air purifiers that help in dealing with air contaminants. They basically aid in the removal of contaminants like pollen, dust, mold, spores, among others .This is very important especially for people who suffer from asthma or allergy since exposure to such air contaminants has health effects .Such people normally develop symptoms like wheezing, coughing, chest tightness and shortness in breath in case of asthma. For allergic sufferers, they may develop symptoms like coughing or body rashes. Understanding how the ionic air purifier works is very essential and it may influence your decision on whether to purchase it or not.

How does the ionic purifier work?

ionic purifier

This air purifier basically uses high voltages to electrically charge air molecules. The negatively charged ions, also known as anions, created are then released into the air. The emitted anions end up attaching themselves to molecules in the air, making the molecules gain negative charges. Afterwards, the negatively charged airborne particles end up attracting positively charged particles of contaminants in the air. In the end the clumping of these oppositely charged particles causes the formation of heavier particles. The heavy particles, due to their weight, end up falling to the floor and forming a dirty spot around the ionic purifiers.


This particular air purifier has mechanisms that enable it to perform certain tasks that other types of air purifiers cannot. The mechanism it possesses therefore makes it stand out in certain situations that need advanced air purifications. Some of the benefits of using this air purifier therefore include;

  • This air purifier is very efficient in removing ultra- fine particles as small as 0.01 microns. This therefore means that it can get rid of most types of air pollutants including the smallest. Therefore, particles in the air don’t stand any chance of remaining in the air, they are effectively gotten rid of in a short span of time.
  • It is ultra-quiet in that it is not noisy when in operation. This will provide a conducive environment for one to stay in even when it is in operation.
  • It is energy efficient. This means that it doesn’t require high amounts of energy to operate. In the end, it saves you on the running costs.
  • It is filter- less hence it will save on the cost of replacing filters.


Most devices that have advantages also happen to have disadvantages. However, for a device to be considered efficient and safe for use, the advantages must outweigh the disadvantages. The ionic purifier is no exception and some of its disadvantages include;

  • It gets rid of the contaminants in the air but not in the house. This is because the eliminated particles end up settling on surfaces like the walls, furniture or floors and they can get back into the air. It is for this reason that this air purifier needs to be used in conjunction with other kinds of air purifiers.
  • It doesn’t get rid of odor. The reason for this is that it doesn’t have the necessary mechanism for odor removal.
  • The ionic air purifier also produces ozone as a by-product. Ozone is a toxic gas that can lead to lung damage if one happens to inhale it indirectly. This is the major disadvantage of using ionic air purifiers. Ozone also triggers asthmatic attacks which are symptomized by chest tightness, coughing, wheezing and shortness of breath. Ozone is therefore harmful to our health. This may call for better means of air cleaning other than using such kinds of air purifiers. You can choose to use another type of air purifier instead of using the Ionic air purifier. Asthmatic or allergic sufferers are advised to find better kinds of air purifiers. Despite this major disadvantage, the ionic air purifier is very effective in getting rid of ‘stubborn’ air pollutants. It is readily available in the market at an affordable price.

What function of Filters is

What function of Filters is ?


These are devices used to eliminate pollutants such as bacteria, mold, dust or pollen from the air. They are mainly composed of fibrous materials which trap the air pollutants .Filters are normally used in places where the air quality is a very essential issue, an example being the hospitals .It is therefore fitted in; the engines of aircrafts and cars, vacuum cleaners, air purifiers, among other machines. There are many types of air filters available in the market. Some of them include;

  • HEPA (High -Efficiency Particulate Air) Filter

    High Efficiency Particulate Air

This air filter was originally developed for the elimination of radioactive particles in the air. It has been used in the making of home air purifiers because of its power to eliminate almost all air pollutants. HEPA filters get rid of 99.97 percent of air pollutants as small as 0.3 microns .They efficiently get rid of air pollutants such as pollen, dust, mold among other pollutants .These pollutants are commonly referred to as allergens .This is because they trigger asthmatic symptoms in asthma sufferers . They also cause allergic reactions such as the sudden presence of body rash. This air filter, however is ineffective in getting rid of other air pollutants like smoke, chemical fumes and harmful airborne microorganisms like bacteria and viruses. Some of the common types of air purifiers fitted with this type of air filters include Rabbit Air MinusA2 and IQAir MultiGas.

  • Activated Carbon filters

These are powerful air filters which have the ability of absorbing smoke particles and chemical fumes in the air. Carbon has a high absorbing power and this is the reason why it has the ability of trapping smoke either from cigarettes, cigar, pipe, wood fireplace or any other source. Activated carbon filters trap these pollutants as they pass through their small absorbent pores .These pollutants end up bonding with the carbon and hence they are permanently eliminated. These air filters are rarely used alone but instead used in conjunction with other types of air filters. Once they trap the necessary air contaminants, they don’t release them back into the air. They permanently eliminate them. However, these air filters have proven to be inefficient in getting rid of allergens and harmful airborne microorganisms.

  • Ionic Filter

This air filter uses a different mechanism of getting rid of air pollutants .Basically, through its negative ion generator, it produces anions which are emitted into the air. The emitted anions end up getting attracted to positively charge airborne pollutants. Due to the attraction and combination, the negative and positive charged particles end up forming heavy particles which fall to the ground due to their weight. This is the reason why dark spots can be observed around the air purifier that uses ionic filters. This air filter can get rid of pollutants as small as 0.01 microns. However, it has some disadvantages that can include; it produces ozone which is a toxic fume, the fallen particles of pollutants may get back into the air and it doesn’t get rid of odor in the air.

  • UV Light Air Filters

This air filters depends on the reaction between ultraviolet light and a catalyst, titanium oxide , so as to get rid of air pollutants. When harmful air particles such as bacteria or mold encounter this reaction, they end up being broken down hence neutralized. Therefore, this air filter is very efficient in dealings with harmful microorganisms such as bacteria and germs. However, it is inefficient in eliminating air pollutants like chemical fumes, smoke, odor and other kinds of allergens. It is therefore used together with other types of air filters.

These are basically the major types of air filters .Other types include the Pre -filter which is common in many air purifiers. This air filter gets rid of particles which have large particles and also gets rid of pet hairs. It acts as a primary filter in air purifiers .Another type of air filter commonly used is the Antibacterial and Germicidal Filter.

Types of Air Purifiers

Types of Air Purifiers

There are many types of air purifiers in the market. Air purifiers are actually devices used in the cleaning of air. They have mechanisms which enable them to purify the air. Different air purifiers have different ways of purifying the air. Here are the different types of air purifiers which have different air purification mechanisms.

The use of filters to purify the air is one type of mechanism that air purifiers use. The polluted air has to pass through an air filter for it to be purified effectively. Air purifiers with filters are sometimes referred to as Air cleaners. Air filters however can work on their own and act as actual air purifiers. A filter housing, for instance, can be placed between the furnace and the return duct. Placing the filter at such a position will allow the filtration of the air flowing into the furnace. Moreover, installing the filter will also prevent the furnace from damage which might be due to the accumulation of dirt and dust. In addition, air filters can also be installed in the return air vents of each room in the house. Air filters are capable of trapping even the smallest particle of contaminant. Pleated filters, for example, have the ability of trapping small particles because they have large surface area.

Ionizing purifiers use corona discharge method to make ions. Most of the atoms in the air have a neutral charge which in simple terms means that they possess similar number of positive and negative ions. However, when molecules pass near the corona discharge, which basically is a small but intense electric field, they will either have one electron removed or end up gaining an extra electron .Therefore, the contaminants in the air will either become positively or negatively charged in the end. The ionizing purifier also has two metal plates where one is positive while the other is negative. These metal plates will end up attracting the different charged air contaminants hence eliminating them from the air.

This particular air filter is among the best filters. It was originally designed for the elimination of airborne radioactive materials. It has ever since been adapted in different places including homes. It can capture 99.97 percent of airborne pollutants with a minimum size of 0.3 microns. It is very efficient and also very effective in dealing with contaminants.

This device has certain similarities to an ionizing purifier but it has been made in such a way that it alters the atoms of oxygen and hence produces ozone in the process. Ozone is basically made of three oxygen atoms but the oxygen gas present in the air happens to have two oxygen atoms. This device therefore uses UV light or coronary discharge method to split the dioxygen molecules in the air. During the recombination of these oxygen atoms some end up forming ozone. The extra oxygen atom in Ozone happens to be unstable and therefore can break off and hence alter the composition of an organism or anything which it comes across. It is due to this reason, that ozone is used in dealing with contaminants like mildew and mold. It alters the composition off such organisms and hence rendering them harmless.

Ultraviolet radiation sterilizes harmful micro-organisms in the air such as bacteria and viruses and hence makes them harmless. There are certain types of air purifiers which use ultraviolet light to get rid of airborne microorganisms like viruses and bacteria.

Adsorption basically means the process in which a substance ends up being trapped on the surface of another substance. Most air purifiers use adsorbents to get rid of odor, smoke and chemical fumes in the air. The most common type of adsorbent used is the Activated charcoal. This particular adsorbent has small pores which happen to react with smoke and chemical fumes as they pass through it. It is therefore efficient in dealing with gaseous pollutants.