Air purifiers remove contaminants from the air. They come in many sizes and utilize several different technologies. Small stand alone units are designed for residential use. Large units designed for use in medical, industrial, and commercial industries are usually attached to air handling units (AHU) or heating, ventilation and air conditioning (HVAC) systems.
These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics, and at reducing or eliminating second-hand tobacco smoke. Industry also uses air purifiers to remove impurities such as CO2 from air before processing.
Use and benefits of purifiers
There are many particles commonly found in our air that which can trigger allergic reaction in people who are sensitive to these substances. They include dust, pollen, pet dander, mold spores, and dust mite feces and many more. Some things in our air, particularly smoke particles and volatile organic compounds (VOCs), can lead to serious health conditions. VOCs can lead to sick building syndrome. A good air purifier can be effective in reducing the concentration of these airborne contaminants. People who suffer from allergies and asthma find air purifiers to be very useful.
Many technological advancements have been made in air purifiers which has increased their capability of capturing a greater number of bacterial, virus, and DNA damaging particulates.
Some of common methods of air purification include:
Thermodynamic sterilization (TSS) - Uses heat sterilization via a ceramic core with micro capillaries. 99.9% of microbiological particles - bacteria, viruses, dust mite allergens, mold and fungus spores - are incinerated.
Ultraviolet germicidal irradiation - In a UVGI system fans are used to force air to pass by UV lamps which sterilizes the air.
Filter based purification - Filters are used to capture particles as they are forced through the filters.
HEPA - 99.97% of 0.3-micrometer particles are removed by HEPA filters.
Activated carbon - Activated Carbon is used to absorb volatile chemicals on a molecular basis, but does not remove larger particles.
This process merely changes contaminants from a gaseous state to a solid state. Contaminants can be regenerated if they are when aggravated or disturbed.
Polarized-media electronic air cleaners - These filters combine elements of both electronic air cleaners and passive mechanical filters. Most polarized-media air cleaners establish a polarized electric field using safe DC voltage. As airborne particles pass through the electric field they become polarized and then adhere to a disposable fiber media pad.
Photocatalytic oxidation - (PCO) is a new technology which is being used in HVAC industry. Organic contaminants are completely oxidize and degraded in Photocatalytic systems are able to. In addition PCO systems offer substantial energy savings over other methods by limiting the introduction of unconditioned air to the building space.
Ionizer purifiers - Electrically charged air or gas ions are generated using electrically charged surfaces or needles. These ions attach themselves to airborne particles. an electrically charged collector plate then attracts these particles. Trace amounts of ozone and other oxidants are also produced as by-products.
Ozone generators - Ozone generators produce significant amounts of ozone gas as the name implies. Often times these systems are sold as whole house systems. Ozone is a very strong oxidant which has the ability to oxidize many different chemicals.