Air purifiers and sanitizers equipped with active electrostatic filtration and negative ionization such as Erio DEPUR20, are able to guarantee air purification and at the same time hygienic, antibacterial and antiviral effects.

Electrostatic Filtration, also called electronic filtration or electrostatic purification (ESP), is a well known technology that uses high levels of electrical voltage and ionization fields to capture dispersed airborne particles and microorganisms. The operating principle of filtration in the device is developed in two phases: – the conferral of an electrical charge to airborne particles and microorganisms – the electrostatic precipitation of charged particles/microorganisms. The electrostatic filter is therefore constructed with two separate sections: – an ionizing section – a collection/precipitation section. In the first phase, the charge of particles and microorganisms (e.g. bacteria, spores, yeasts) occurs in the ionization section through electrodes that generate a positive or negative corona discharge. In the second phase, the electrostatic precipitation of the previously charged particles and microbes occurs in the collection section, on a series of parallel electrically charged collection plates. The electric field generated between these plates captures the particles and traps them on the surface of the collection plates. Contact with the plates causes immediate destruction of any microorganism and prevents the release of endotoxins when the bacteria are lysed as in mechanical filters. The main advantages of Electrostatic Precipitators (ESPs) are the following: – capture particles from 0.01 μm to 100 μm up to an efficiency of 99% – operate at high airflow rates – operate at high particle loads, 500 grams/m3 – have low energy consumption and low operating costs – there are no replacement and disposal costs Electrostatic filtration technologies also show specific advantages when applied to air decontamination of critical areas in hospital environments where airborne diseases are often widespread. The efficiency of air filtration is high, as they collect particles of all sizes, including ultrafine particles. The destruction of microbes is managed effectively and the system is also able to remove Volatile Organic Compounds (VOCs). The usefulness of ESP technology in biological aerosol mitigation has been demonstrated using both bacterial endospores and various bacterial species. This technology destroys microorganisms transported by airstreams before they risk becoming contaminants to humans. ESP is therefore considered an “active homicidal filtration”. This is because it does not allow microbes, fungi or spores to vegetate and thrive on the surface of the filter, also preventing the release of substances into the environment from the metabolism and destruction of the captured microbiological flora. Filtration with mechanical fiber filters is a technology that has many shortcomings: the quality and quantity of clean air decreases with the passage of time, the filters become clogged causing an increase in pressure drop, noise and energy consumption, together with a laborious change of filters, becoming, in the long run, an uneconomical solution. In addition, HEPA filters that are usually used in conventional air purifiers are only effective less than 0.3 μm, thus excluding viruses and micro-toxins. Literature and laboratory tests confirm the effect of electronic filters against viruses moving in airborne particles. Atmospheric particulate matter acts as a transport vector for many chemical and biological contaminants, including viruses: there is a solid scientific literature relating the incidence of viral infection with concentrations of atmospheric particulate matter such as PM10 and PM2.5. Since even ultra-fine PM1 particulate matter (between 0.3 and 1 micron in size according to EN ISO 16890) falls within the scope of “Expansion Electronic” filters, they are effective against airborne viruses. The failure to release the particulate matter and the particles captured and deposited on the electrostatic filter if the air purifier or the filter itself is switched off is tested and certified by the University of Lucerne: this guarantee makes the delicate maintenance phase, which consists of washing the filter with water and detergent, safer at the same time.

Moreover, since the filter can be completely regenerated by washing, additional replacement and disposal costs are avoided, thus guaranteeing considerable savings in tea.