Compare air cleaning technologies

 

Feature	Radiant UVC	UVC Filter	Ioniser	PCO / PECO Filter	HEPA Filter	Airora
Works safely 24/7 with people present	N	Y	Y	Y	Y	Y
Destroys all types of harmful virus, bacteria and mould	Y until people return	Only within the device	N	Only within the device	N	Y
Creates an active person to person infection barrier	People cannot be present	N	N	N	N	Y
Rapidly destroys active airborne viruses, bacteria and moulds throughout an indoor space (Airora is 1000+ times more effective than any filter)	Y until people return	By circa 50% after an hour	N	By circa 50% after an hour	By circa 50% after an hour	Measured at 99.9999% in 5 minutes
Destroys all types of harmful viruses, mould, and bacteria on all exposed surfaces throughout a room	Y if in direct line of sight	N	N	N	N	Y
Sanitises all the air and exposed surfaces in an indoor space, not just the air that passes through the device	NA	N	N	N	N	Y
Breaks down and removes harmful gaseous pollution (VOC’s, carbon monoxide, formaldehyde, ammonia etc.) throughout a room	N	N	N	N	N	Y
Neutralises all common allergens and lung irritants, such as pollens, spores, pet dander, cat saliva and house dust mite excretions throughout a room	N	N	N	N	N	Y
Removes all types of Odour throughout a room	N	N	N	N	N	Y
Breaks down and removes dangerous ultra-fine and nano particles throughout a room	N	N	N	N	N	Y
Controls the level of indoor ozone, reducing it to below international safety standards	N	N	N	N	N	Y
Whisper Quiet (Bedroom friendly!)	NA	N	N	N	N	Y
Low energy use	N	N	N	N	N	Y

The limitations common to ALL filter-based air purifiers

ALL traditional filter-based air purifiers (including HEPA, Electrostatic, UVC & PCO) share the same basic failings: they only filter out some types of pollutant, not all, and they only clean the air that passes directly through them:

• All filter-based technologies, whatever their type, only reach their maximum level of pollution reduction (typically circa 50% - Novoselac & Siegel 2009) after more than an hour and take a similar time to dilute any new source. 
• Sadly, filter devices often (deliberately?) mislead by quoting efficiencies of > 99%, but that only applies to the removal of the larger particles in the air that have passed through the device, not to the air throughout the room.
• HEPA filters, ‘the gold standard’, only capture circa 10% of the particulates that pass through them (the larger particulates), the other 90% of ultra fine and nano particulates are also of concern.
• UVC filters use germicidal UVC light to sterilise the air passing through, but germicidal UVC takes time to sterilise, and there is much scientific debate about 'how long' and thus how fast the air can flow until they become ineffective. The EPA says: "typical UVGI cleaners used in homes have limited effectiveness in killing bacteria and moulds.
• Filters remove particles from the air passing through the filter but the filtered air they emit is immediately re-contaminated by mixing.
• Stratification (caused by warm air rising) and eddies (circling air), and the fact that existing air is constantly being replaced by new air from outside, means that much of the air in a room will never even pass through the filter. This effect is often compounded by a lack of filter 'suction' compared to room size.
• Filters typically only capture particulates, not gaseous pollution.
• Filters are particularly ineffective in capturing allergens, as allergens quickly settle on the floor and surfaces and remain there until disturbed after which they again become airborne.
• As filters don't produce a hydroxyl cascade, they don't decontaminate surfaces or neutralise viruses, bacteria, mould or pollens within the room.
• While larger, more powerful, noisier fans can filter more air, in practical terms they can never overcome these failings.

Indeed, a recent comprehensive review by the University of East Anglia Medical School of a wide a range of filter types, 

in applications ranging from air conditioning to portable units, 

found no evidence  that such filter devices prevent transmission of respiratory or gastrointestinal diseases.

The limitations of air ionisers

Ionizer air purifiers are often marketed with a variety of names, such as “ion air purifiers”, “negative ion air purifiers”, “air ionizers,” and “bipolar needlepoint ionization”. 

The principle is that an air ionizer shoots out negative ions into the air and those ions in the air cause airborne particles to stick to surfaces, like a bed, a wall, the floor or even your face (is that really a good thing?).

The truth is different:

• Air ionisers only create abundant ions close to the device, not throughout the entire room. Local to the device, particulates, including microbes, may be charged and then adhere to nearby surfaces, but they will easily be disturbed and made airborne again.
• The latest research by Boeing demonstrated that across a 'real' environment the intensity of ions created by air ionisers was insufficient to have any material biocidal effect.

The limitations of rudimentary hydroxyl generators (including PCO, PECO and Photocatalytic)

In addition to the longstanding filter technologies, some manufacturers have produced air filters based on rudimentary Hydroxyl Radical technology. 

• While such PCO / PECO / Photocatalytic devices create hydroxyl radicals within the device, those hydroxyls are so short lived (typically < 0.2 seconds) that their effect does not generally nor materially extend outside of the device.  
• Consequently, these rudimentary hydroxyl based air cleaners rely almost entirely on exposing pollution to hydroxyls within the device. As such they are 'filters' and share the same limitations as all other filter-based air purifiers.
• Sadly, the claims made for this basic technology are often grossly misleading, including an evidence free implication that the hydroxyls created spread outwards from the device in sufficient quantities to effectively sanitise the air and surfaces throughout the room. 

The limitations of Radiant UVC Disinfectors

A unique characteristic of UV light is that a specific range of its wavelengths, those between 200 and 300 nanometers, are categorized as germicidal – meaning they are capable of inactivating microorganisms, such as bacteria and viruses. Devices known as 'UVC Disinfectors' create intense UVC germicidal light (dangerous to humans) which is used to treat an empty room and its contents for a period, killing airborne and surface pathogens. While the process itself may be relatively effective (for a short period), it has many obvious drawbacks compared to a technology which can achieve the same or better results, but safely run 24/7 with people present.

Indeed, UVC Disinfectors most obvious weakness is that as soon as a room newly disinfected with UV-C light is reoccupied, 

it is rapidly re-contaminated!

Additionally, using a UVC Disinfector as an anti-microbial device:

• Requires trained personnel working strictly in accordance with a safe method of work statement.

• Typically needs a full time member of staff to move and operate the device to get sufficient usage to justify its high initial cost.

• Requires the space to be treated to be empty of people and secured so that people, pets etc. cannot accidentally enter the space being irradiated.

• Only destroys pathogens in a direct line of sight of the device, so there are always surfaces that will not be cleared of pathogens - it may well require repeated treatments with the device in different locations within the room in an attempt clear most surfaces.

• Requires the operator to move the curtains, take things off walls, open drawers and cabinets, expose telephones, remote controls and other high-touch surfaces so that the light reaches them.

The limitations of 'Foggers'

A 'Fogger' is a device that creates a chemical fog to kill bacteria and / or viruses.  Such chemical 'fogs' are dangerous to humans, and so foggers are used to fumigate spaces without people being present.  While the process itself may be effective (for a short period), it has many obvious drawbacks compared to our technology which can achieve better results, but safely run 24/7 with people present. Indeed, UVC Disinfectors most obvious weakness is that as soon as a room newly disinfected with UV-C light is reoccupied, it is rapidly re-contaminated!

Other drawbacks of using a 'fogger' as an anti-microbial device:

• Requires trained personnel working strictly in accordance with a safe method of work statement.

• Requires the room or space to be treated to be empty of people and secured so that people, pets etc. cannot accidentally enter the space being fumigated.

• Requires items likely to be damaged by the fumigant to be removed, and later replaced, to protect them from damage.
• Requires the transportation, storage or handling of toxic chemicals.

 

You can find out all about Airora at airora.com

And contact us at support@airora.com