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      ASPRA air purification


      What does the ASPRA technology purify?ASPRA technology

      There are many different air contaminations that influence the air quality. These contaminations are the particles that are removed effectively from the air by the ASPRA technology. This is done without the use of conventional textile filters or other expensive filters. The technology uses an open structure ASPRA collector. Contaminations from the air that are removed by the ASPRA products are:

      • Dust
      • Particulate matter (PM10, PM2.5, PM1)
      • Ultrafine particulate matter (PM0.1, submicron and nano-particles)
      • Microbiological contaminations (viruses, bacteria, fungi, spores and pollen)
      • VOCs (volatile organic compounds) and odours
        (By adding a VFA Active Carbon Filter)

      The ASPRA is a revolutionary application for air purification. The system applies a very high air purification efficiency (up to E10-11/HEPA classification according to NEN-EN 1822 standard), without using a HEPA filter. As a result, the ASPRA has 80% less pressure drop compared to conventional filters, hereby realizing substantial energy savings compared to conventional filters. The ASPRA only charges particles inside the application, and captures them directly on the own open structure filter (a collector). No harmful radicals are produced. 

      The ASPRA is a modular system with diverse models and application possibilities. The ASPRA is available in various standard versions, but can easily customized to the specific requirements of the customer. Providing tailor-made solutions to ensure an optimal solution.



      ASPRA benefits

      • High efficiency purification
        High efficiency filtration of particles and gases without using conventional, non-sustainable, expensive and very high pressure drop textile filters.
      • Low energy consumption
        Due to the open structure of the filter: the collector generates 80% less pressure drop (air resistance) compared to conventional systems.
      • User-friendly
        Each model is very user-friendly
      • Safe maintenance
        The ASPRA collectors absorb no moisture at all, hereby preventing fungi or bacteria growth.
      • Flexible
        Our broad product range and custom solutions are adaptable according to your needs.



      The products from the ASPRA series are tested by several independent institutions such as TNO, VITO and ECN. Tests confirm the air cleaning efficiency of the ASPRA technology is 97-99% of atmospheric particles in the range of 0,1-10 micron. (PM10, PM2.5, PM1, PM0.1 / ultra fine particles).


      How does the ASPRA technology work

      The air is led through the tube either by using a built in fan or by using the existing air flow in a ventilation shaft / system. In the first part of the tube, the air with all contaminants is exposed to an electrical field, which is responsible for charging airborne particles, causing them to attach to a specially designed static particle collector. What remains is purified, clean and healthy air.

      Then the viruses, bacteria, other pathogens and other aerosols (pollutants and virus carriers) such as particulate matter are captured on an open structure filter and hence collected in the collector (the filter) itself and permanently removed from the air and the room. The electrical field within the system leaves the majority of the biological pathogens (bio-aerosols) killed or deactivated. The ASPRA creates clean and particle free air, resulting in healthy environment and substantially reducing the risk of short- and long-term diseases spreading through the air.


      ASPRA technology

      Charging the particles before catching them allows us to use an open structure collector instead of a dense filter. This way we use much less energy for pushing the air through the collector while achieving high filter efficiency. Replacing the collector is easy and can be performed by anyone.


      The difference between ASPRA and other air cleaners and ionizers

      Clean air is made possible by tackling the source, but also purifying the air. There are many different air purifiers on the market. These are often equipped with a standard filter. But there are also newer, efficient techniques, such as air cleaners with ionisation. We explain what the differences between the ASPRA and such techniques as well advice on what you should pay attention to.

      1. ASPRA

      The ASPRA is a high efficiency Electrostatic precipitation and filtration system and technology. It combines the best features of closed ionisation and mechanical filtration in one. The ASPRA is patented technology developed by Virus Free Air BV and VFA Solutions B.V. generates a controlled positive electrical field to charge the particles and capture them within the system. Coarse particles can then precipitate / deposit on the inner part of the system which operates as an electrostatic precipitator (ESP), while the extra small particles are collected on an open structure static filter.

      In additional to safety and the many other specific advantages of the ASPRA, a general advantage of such air cleaners that capture particles with a special open structure filter, as the ASPRA, is that it does not become clogged and less energy is needed to move the air through this filter.


      2. Air cleaner with standard filter

      With a standard air purifier, a fan is used to start an air flow. The airflow is then passed through a filter in which air pollutants are captured and the air quality will improve. The smaller the particulate matter particles, the more dense filters should normally be to capture the (risk) particles. A point of attention is that the filters must be regularly cleaned / replaced. They are full and pollution is accumulating. The fan has to work harder and that results in more energy consumption, lower capacity and more noise. In addition, many filters are made of moisture-containing materials such as textiles or fibers, where bacteria can start to grow.


      3. Air cleaner with ionization

      Ionization is a newer technique with many developments. It is an innovation that is used more and more often, for example from the point of view of sustainability and energy saving.

      There are many air cleaners on the market that use ionisation. There is a difference between air cleaners that use positive ionisation and negative ionisation. Ionisation (positive or negative electrical charging of atoms or molecules) provides ions that, when attached to dust particles, produce charged dust particles. Loaded dust particles then stick more easily on all kinds of surfaces.

      In addition, there is another difference in air cleaners with ionisation, namely air cleaners that charge electric particles (without filter) and air cleaners that charge electric particles, but also capture them immediately. The first is called open ionization (1) and the latter is called closed ionisation (2):

      (3.1) Open ionization:

      The charged particles are spread into the room and they themselves look for a surface to be deposited on. They thus deposit on all surfaces in the room such as furniture, ceiling, walls, appliances, but certainly also our lungs. These systems create many charged particles, but also free ions, which are often negatively charged. This is then called negative ionisation. Other systems generate bi-polar ionization (positive and negative ions at the same time) claiming that positive and negative charges and charged particles then colloid and agglomerate into larger particles and hence fall down from the air. All products using open ionisation are classified as ‘Electronic Air cleaners’ according to ASHREA and are negatively advised to use. The reasons for that are as follows:

      The impact of open ionisation is scientifically questionable and may be only temporal. Since these products normally lack any control of the ionization and electric field, they typically generate excessive amounts of ions in the air causing the generation of hazardous by-products, such as ozone, free radicals and free ions. Although they may contribute to reducing odour and/or viruses, they can be still harmful to health. Research shows that charged particles can settle into lungs up to 5 times more easily than non-charged particles.

      (3.2) Closed ionization:

      The charged particles are captured on a special surface in the system itself, so that the particles are not blown into the room and therefore do not settle on other surfaces. With closed ionisation, there can be both positive and/or negative ionization. The capture surface can be of various materials, such as conventional filters, metal plates known as Electrostatic precipitator (ESP) or special static filters. The level of ionisation is such systems is normally lower than with open ionisation as they intend to charge the particles to enhance their attachment to the collection surface.