Σύγκριση της τεχνολογίας υδροξυλίου με άλλες τεχνολογίες

 

Χαρακτηρισιτκό

OH-FEEL

Hydroxyl

Filters

(HEPA)

Photocatalytic

Oxidation(PCO)

Ionizer

Germicidal

UV In-Duct

Foggers

Safe for Occupied Spaces 24/7

X

Reduce Pathogens in

air – Inside the Device

X

Reduces Pathogens in

air – Outside the Device

X

Limited¹

Limited²

X

safe until people return

Kills Pathogens On Surfaces

X

Limited¹

Limited²

X

X

Destroys all types of harmful viruses,

bacteria and mold throughout a room

X

Limited¹

X

X

VOC & Odor Removal in

Air – Inside the Device

X

X

X

VOC & Odor Removal in

Air & on surfaces – Outside the Device

X

Limited¹

Limited²

X

X

Creates an active person-to-person

infection barrier (restricts cross contamination)

X

X

X

X

People cannot

Be present

Sanitizes all the air & surfaces

X

X

Limited

X

X

Breaks down ultra-fine particles throughout the room (PM2.5)

X

X

X

X

X

Neutralises allergens, pollens, mold spores,

pet dander, dust mite excretion in the room

X

X

X

X

Partial until

People return

Destroys all types of airborne germs, bacteria, viruses, and mold throughout the room

Typically 50% after one hour ³

Typically

50% after

one hour ³

X

X

Yes, until people return

Destroys all types of harmful germs, bacteria, viruses and mold on all surfaces throughout the room

X

X

X

X

Yes, until people return

Breaks down and removes harmful gaseous pollution (TVOC’s, carbon monoxide, formaldehyde, ammonia) throughout the room

X

X

X

X

X

¹     Hydroxyl production is restricted to the catalyst surface resulting in very limited production of organic oxidants

²     Reactivity of ions and O² are short lived, effect drops of quickly as distance from ion source increases.    

³     Filter system generally eliminate 50% after one hour, they cannot clean all the air (Study by Novoselac and Seigal 2009)

Comparing Air Cleaning Technologies

The problems with ALL filter-based air purifiers

All traditional filter-based air purifiers (including HEPA (High-Efficiency Particulate Air), Electrostatic, UV-C (Ultraviolet-C) and PCO (photocatalytic oxidation)) 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:

  • Filter-based technologies only reach their maximum level of pollution reduction (typically around 50% – Study by Novoselac & Siegel 2009) after more than an hour.
  • Filters remove particles from the air passing through the filter but the filtered air they emit is immediately re- contaminated by mixing with unfiltered air.
  • 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’ (fan speed) compared to room size.
  • Filters typically only capture particulates, not gaseous pollution (VOC’s).
  • As filters don’t produce a hydroxyl cascade, they don’t clean surfaces or neutralize viruses, bacteria, mold or pollens within the room.

While larger, more powerful, noisier fans can filter more air, in practical terms they can never overcome the above failings.

Compare Air Cleaning Technologies

Disadvantages of Other Technologies

What is it?

A HEPA (high-efficiency particulate air filter) has to meet specific minimum standards of efficacy for its ability to remove particulates above a particular size from the air that passes through it.

Disadvantages

All traditional filter-based air purifiers (including HEPA, Electrostatic, UVC etc.) 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:

  • Filter-based technologies only reach their maximum level of whole room pollution reduction (typically circa 50% – Novoselac & Siegel 2009) after more than an hour.
  • 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.​
  • As filters don’t produce a hydroxyl cascade, they don’t decontaminate surfaces or neutralize viruses, bacteria, mould spores or pollens within the room.
  • While larger, more powerful, noisier fans can filter more air, in practical terms they can never overcome these failings.​

 

What is it?
Some manufacturers have produced air filters based on rudimentary Hydroxyl Radical technology.
Disadvantages
​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 or materially extend far 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 principally ‘filters’ and share the same shortcomings as all other filter-based air purifiers:​​
  • Filter-based technologies only reach their maximum level of whole room pollution reduction (typically circa 50% – Novoselac & Siegel 2009) after more than an hour.
  • 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.
  • As filters don’t produce a hydroxyl cascade, they don’t decontaminate surfaces or neutralize 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.​
Sadly, the claims made for this basic technology are often grossly misleading, including an evidence free implication that sufficient hydroxyls spread outwards from the device to effectively clean the air in the room and surfaces.

What is it?

Ionizer air purifiers release ions (charged particles) into the air.  It is postulated that these ions collide with airborne particles such as dust or pathogens, thereby giving them a charge. The now charged particles are then attracted to surfaces, such as walls and curtains, or sink to the floor, taking them out of the air.
Under some conditions, and over a relatively lengthy period of time, the presence of high levels of ions has been shown to damage some types of bacteria, viruses and mould sufficiently to make them non-viable.
​However, the reality is starkly different …
Disadvantages
  • As with HEPA filters, ionizers have the drawback that they only effect particulates, not gasses.
  • Maintaining a sufficiently high intensity of ions throughout an entire space is practically impossible, as evidenced by Boeing’s latest research, which was unable to demonstrate any material biocidal effect on surface-borne pathogens during their extensive testing.
  • Any effects tend to be very local as ion intensity drops off naturally and rapidly away from the device. Indeed, LifeAir’s own published data shows that only around 1% of ions remain active just 1m away from the device!
  • Local to the device, particulates, including microbes, may be charged and then adhere to nearby surfaces (like soft furnishings), but they will easily be disturbed and made airborne again.
  • Even if they were generally effective in removing particulates (including viruses and bacteria) from the air to surfaces in the room then, as the particles gradually lose their charge, or they are disturbed, they will be re-adsorbed back into the air.
  • If an ionized pathogen is inhaled, it is more likely to stick to the walls of your respiratory system thus increasing the chance of an adverse reaction.
  • Ionizers often increase the level of ozone in a room, possibly beyond safe levels.​​​​ Indeed research at the University of Leeds has shown that pathogens that eventually become non-viable in the presence of ions are primarily damaged by the related ozone and not by the ions nor their associated charge!
Sadly, there are grossly misleading and false claims being made for this type of air cleaner.

Germicidal UV in Duct

What is it?

Germicidal UV in duct is UVC lights installed in your HVAC system to clean out the ductwork system. These high-energy rays can damage the DNA of microorganisms, and prevent them from infecting or reproducing.

Disadvantages:

  • Expensive Installation Costs and Bulb Replacements
  • Potential safety hazards
  • Limitations of effectiveness
  • Does not treat surfaces in the room
  • Every air handling unit is different and requires different specifications before UVC products can be installed. This can be costly.
  • Doesn’t remove allergens like pet dander
What is it?
A ‘Fogger’ is a device that creates a chemical fog, such as ozone, for example 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 a technology which can achieve better results, but safely run 24/7 with people present.
Disadvantages

One major disadvantage is that as soon as someone walks into a newly fumigated room, it’s immediately 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

Oh-Feel technology is entirely safe, requires no supervision, and can be operated 24/7 with people present.