Please note that the claims being made in the following communication only apply to European countries. For locations outside of the European Economic Area (EEA) you should first review local regulatory restrictions. For the USA, the product is not available until the pending registration with the United States Environmental Protection Agency (US EPA) has been completed.

Reducing the aerosol concentration in buses through air filtration

Innovative three-stage filtration design for best possible protection

Freudenberg Filtration Technologies offers innovative filtration solutions for touring coaches and public buses. The filters are based on Freudenberg’s successful micronAir blue cabin air filters and provide active protection by significantly reducing the concentration of viral aerosols. This is achieved by a unique multi-layer design that effectively filters, separates and retains inorganic and biological particles and aerosols. Air filters can thus reduce the aerosol concentration in public transport and make the expected increase in bus travel, post the pandemic safer.

Protection bus passengers

Learn more about how micronAir blue cabin air filters provide decisive protection against virus transmission

Unique three-stage progressive filter solution for buses

In order to achieve optimized air quality on buses, filtration is an important aspect, together with the frequency of air exchange, an increased proportion of fresh air, and reduced air turbulence. Freudenberg’s initial prototype is based on a bus model with a three stage filter system: a front box filter to clean the air for the driver, a recirculation filter mat in the ceiling, and a third filter in the air conditioning unit on top of the bus. The result: a unique three-stage progressive design in which all filters are carefully aligned with one another.

Three-stage filter solution for buses

Air filters for buses – the three filtration stages

  1. Firstly, an initial filter in the front of the bus filters the air entering the vehicle via the driver’s cabin.
  2. The second step is the recirculation filter mat. This is where the used cabin air, potentially carrying infectious aerosols or other harmful particles, passes through first. The mat is designed to capture all the larger aerosols and particles to keep them out of the air conditioning. Focusing on larger particles at this stage prevents the recirculation filters from becoming clogged too quickly, while already eliminating potentially harmful elements.
  3. Ultimately, the filter in the air conditioning takes care of the ‘fine tuning’, using a superfine filter to remove even smallest particles from the pre-filtered air.

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Info Graphic

Information graphic: Travelling by bus after Covid-19


micronAir blue cabin air filters: Reducing the aerosol concentration in buses

Reduce infection risks in public transport systems

micronAir blue with anti-viral properties: Three-layer filtration for best possible protection in buses

The fine particle filtration layers in the premium micronAir blue cabin air filters provide decisive protection against virus transmission. They demonstrably separate not only droplets (> 5 μm), but also critical viral aerosols (droplet nuclei significantly below 5 μm).

  1. The first two layers thus capture the majority of ultra-fine viral aerosols.
  2. In addition, the third bio-functional layer inactivates collected viral contaminants, therefore effectively suppresses the release of active viruses back into the cabin air. This has been conclusively proved by a comprehensive series of tests conducted at an independent external institute, specialized in microbiological analysis.

The high particulate and viral aerosol filtration performance is sufficient to significantly reduce the concentration of airborne viral aerosols. In this way, micronAir blue cabin air filters make a substantial contribution to
minimizing the risk of virus transmission inside buses.

Key product features at a glance

  • State-of-the-art three-stage progressive filtration design in which all filters are carefully aligned with one another
  • Can trap approximately 90 percent of viral aerosols – in addition, the innovative bio-functional layer, impregnated with fruit extract, inactivates almost 100 percent of captured viral load
  • Close collaboration with leading international test institutions to achieve thirdparty product validation
  • Tailored filter solutions for buses in OE quality from the preferred development partner of the automotive industry
Cabin air filters for buses
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cabin air filters for vehicles

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