The different indoor air treatment solutions
How to choose your air purifier?
Due to the current sanitary context, air purifiers are increasingly in demand and the issue of indoor air quality is better taken into account.
A wide choice of devices is available on the market, but unfortunately all the technologies used are not equal.
On such technical and sensitive subjects, having questions is legitimate and essential.
Which air purifier to choose?
Which technology is the most efficient and why?
What are the differences between ionization, photocatalysis or zeolite and which of these processes is the least hazardous to health?
Here are answers to these questions and a summary table to help you navigate them.
Filtration (M5, F6 to F9)
Filters M5, F6 to F9 are “fine” filters (defined by EN779:2012) and finer than G-type pre-filters.
They allow retention of 0.4 micron particles but have the same limits as all types of filters, the microorganisms are not destroyed and remain viable. They require very regular maintenance and do not treat surfaces.
The M5, F6 to F9 filters are opacimetric filters (defined by EN779:2012).
They don’t let the light through. The finer mesh size of the G-type pre-filters (defined by EN779:2002) allows retention of 0.4 micron particles but has the same limits as all types of filters, the micro-organisms are not destroyed and remain viable.
They are widely used in all types of air treatment plants (AOCs).
The main limitations of this purification technology are the risk of contamination of the ventilation network (if the filter is drilled) and maintenance personnel during operations. These filters require very regular maintenance.
This technology does not treat surfaces.
Absolute filtration (E10 to E12, H13/14, U15 to U17)
Absolute filtration is an even finer filtration whose efficiency is almost complete (< 99.98%). This technology has the same disadvantage as all filtration techniques, it captives the micro-organisms and exposes to the same risks of contamination (M5, F6 to F9).
It generates very high pressure losses and does not treat surfaces either.
Activated carbon
Depending on the size of the pellets, the active coal is an equivalent of the M5 filters; nevertheless, the principle of purification is a principle of rapid adsorption of a large majority of pollutants.
Adsorption is not complete and requires a large quantity of coal to be effective and has the disadvantage of generating high pressure losses and saturating relatively quickly. It can be specifically pre-impregnated for better efficiency on some pollutants.
It has the advantage of being cheap.
Zeolite
Zeolites are microporous crystals that are called molecular sieves. They can be of natural or synthetic origin and have a very important but very specific retention capacity. Zeolites have the disadvantage of being very expensive.
Zeolites are crystals formed from a microporous aluminosilicate skeleton, the crystalline character of the skeleton implies that the porosities of the structure are all the same size. They may or may not allow the passage of molecules with a discriminating power (better specificity than active charcoal), therefore they are called
of molecular sieve.
They may be of natural origin (e.g., basaltic or volcanic rock) or synthetic (silica and alumina based). They are used in heterogeneous catalysis.
They have a very important but very specific retention capacity.
They have the disadvantage of being often very expensive, but the advantage of requiring less material, thus generating less pressure losses.
UV lamps
There are 3 main types of UV lamps:
UVA (wavelength between 315 and 400 nm)
UVB (wavelength between 285 and 315 nm)
UVC (wavelength between 200 and 285 nm).
Only UVC are germicidal. This type of lamp requires special precautions in terms of safety since their radiation represents a serious risk of burning of the eyes and can cause skin cancers.
With few exceptions, UV lamps produce ozone.
Wavelengths of 185 nm oxidize oxygen and produce ozone.
Only UVC are germicidal, especially those that produce a specific wavelength of 257 nm; the UVC lamps used in the Ikibox tangential reactor have the specificity of being composed of quartz and not glass allowing to filter the UVC spectrum to let pass only the wavelength of 257 nm.
They act by breaking down dimers (thymine and thymidine from DNA) to destroy microorganisms.
This type of lamp requires special precautions in terms of safety.
Indeed, their radiation represents a serious risk of burning of the eyes and can cause skin cancers (melanoma).
Some of these lamps can be energy-intensive, in which case the power consumption is returned in the form of heat energy. The UVC lamp technology used alone requires contact time to achieve total germicidal efficiency.
In an air treatment system, the efficiency is partial in air as on surfaces.
Ozonation (excluding human presence)
Ozonation is a chemical treatment by oxidation, which produces ozone. It has long been used to sterilize by destroying pathogenic microorganisms. This process is very effective against a certain number of pollutants, however its use in the air must imperatively be carried out without human presence because extremely harmful.
Ozonation is a chemical treatment by oxidation, ozone is produced by oxidizing the oxygen molecule O2 in 03. It has long been used to sterilize by destroying pathogenic microorganisms.
It has the advantage of allowing complementary actions in the destruction of a large number of micropollutants, in the improvement of tastes, odors and in the destruction of colors.
Ozone is an allotropic form of oxygen. As a gas, it is dangerous in air from 0.1 ppm/m3 of air. Its use in the air must be carried out without human presence. It is a very powerful oxidant that is chemically unstable in all gaseous and liquid mixtures, causing it to dissociate into oxygen.
Ozone acts on many compounds:
Destruction of cyanide and phenols
Attacks organic and natural dyes (humic acid, tannins, lignins)
Selectively reacts with organic compounds in water, transforming them into materials that are easier to decompose by subsequent biological treatment.
There are two types of reaction:
Direct with the molecule O3
Indirect due to the action of secondary species such as free radicals
OH- formed by the decomposition of ozone in contact with water.
Unlike chlorine or chlorine dioxide, ozone does not produce haloforms; it has an effective and rapid action, but no residual effect unlike chlorine derivatives.
Ionization
Ionization is an action that involves modifying the charges of an atom or molecule so that it becomes a negative or positive ion.
In the case of air treatment, this technology makes it possible to negatively load pollutants in order to weigh them down. They then deposit on the surfaces. This technology carries significant risks for the health of populations, notably through its significant production of ozone.
Ionization is the action of removing or adding charges to an atom or molecule that loses its neutrality, it becomes a positive or negative ion.
Negative Ions:
A very large quantity of negative ions are created naturally in nature by the action of solar radiation, the wind in the trees, the drops of water in a waterfall creates negative ions, they purify the air a little and also give a feeling of well-being.
Positive Ions:
They are found in large quantities in urbanized environments.
computer screens, photocopiers, for example, air-conditioned rooms, produce them; they accelerate the heart rate and blood pressure; in general, they can induce a feeling of suffocation, give irritability, fatigue, headache, decreased concentration, decreased stress.
The air purifiers that use this technology, change the polarity of the particles, dust and pollutants present, they load negatively and are attracted by the walls or the ground and settle.
It is very difficult to produce a large quantity of negative ions without producing ozone, this technology carries significant risks to the health of populations.
Photocatalysis
Photocatalysis is the use of the oxidizing properties of titanium activated with light to oxidize and/or mineralize a large number of pollutants.
Photocatalysis is the action of a substance called a “photocatalyst” (semiconductor, the most used being titanium) that increases under the action of light, the speed of a thermodynamically possible chemical reaction without intervening in the balance equation of the reaction.
Photocatalysis is based on the absorption of titanium dioxide, a luminous radiation of energy. This energy absorption causes the passage of electrons from the valence band to the conduction band by creating holes (H+) in its valence band.
In a titanium dioxide (TIO2) sample, the average lifespan of an electron varies from millisecond to nanosecond.
It is in this very short period of time that oxydo-reduction reactions can occur.
TIO2 exists in 3 crystalline forms:
Rutile (R), Anatase (A), Brookite (B).
Simply put, photocatalysis is the use of the oxidizing properties of titanium activated with light to oxidize and/or mineralize a large number of pollutants.
The most used form is aeroxide (80% antase and 20% rutile).
Photocatalysis, or heterogeneous catalysis, well implemented is a technology of the future to treat a large number of pollutants in air and water.
It can effectively treat: cyanides, nitrites, metals and organic pollutants (Microorganisms, VOCs, pesticides, polycyclic aromatic hydrocarbons (PAHs), chlorinated solvents, polychlorinated benzenes (PCBs), dyes, compounds
pharmaceuticals, antibiotics, analgesics, steroids,
cyanotoxins…).
Cold plasma
Cold plasma is obtained by creating an electrical discharge in a low-pressure gas. This technology creates by oxidation of ozone in the air which must be absorbed or neutralized in order not to pose a danger to the populations.
Cold plasma is effective against microorganisms, but its effectiveness is very limited against chemical pollutants.
A plasma is an ionized gas, it is a saying whose atoms have lost one or more electrons, thus becoming ions. This ionization can be achieved by submitting
gas with strong heating or a strong electric field.
Cold plasma is obtained by creating an electrical discharge in a low-pressure gas.
This plasma is a cold gas slightly above the ambient temperature. Plasma can be used to manufacture micro or nano objects for space propulsion, low-energy lighting, sterilization, water and air treatment.
Only cold plasma is used to decontaminate air or water.
This technology creates, by oxidation, ozone in the air, which must be absorbed or neutralized so as not to pose a danger to populations.
Cold plasma is effective against microorganisms, but very limited spectrum against chemical pollutants, but cannot be implemented on air treatments beyond 2000 m3/hour.
Ikibox (tangential reactor)
The tangentiel® reactor used in Ikibox technology combines several of the above technologies and its safety has been validated by AFNOR B44A.
Ikibox scrubbers are designed to operate in the presence of living organisms and/or foodstuffs. They are suitable for small and large volumes.
Contaminants (viruses, bacteria, fungal flores), allergens, most gaseous compounds, the main ones being volatile organic compounds (VOCs) and nitrogen organic compounds (NOx), are oxidized by a highly potent patented process.
The complete oxidation of microorganisms and VOCs produces carbon dioxide (CO2) in small proportions and water in small amounts.
For your information, it takes 20 Ikibox 120 to produce the equivalent of carbon dioxide released by a calm person behind his desk for a full day.
The safety of Ikibox technology has been validated by AFNOR B44A.
Ikibox scrubbers are designed to operate in the presence of living organisms and/or foodstuffs. They are suitable for small and large volumes.
Other generations of even more powerful reactors are currently being developed to meet the expectations of manufacturers.
The technology has been developed to reduce maintenance operations to a biennial frequency (every 2 years).
Comparative table and summary
