Nanomaterial-based filters

COVID-19: Testing Service

4C Air is currently testing the filtration efficiency for filters and facemasks. We use industry standard TSI 8130A (0.3 μm NaCl aerosol), consistent with the filtration efficiency tests used for NIOSH N95. Please fill out the form below for a quote if interested.

4C Air does NOT offer fitting tests and the tests offered do NOT serve as certification in place of NIOSH, or any other governmental or regulatory agency's tests. The tests are to give an idea of the filtration efficiency of unknown masks or media which may be necessary in the pandemic.

Testing Service

*Efficiency is determined using TSI's standard CertiTest Filter Tester Model 8130A, rated for 0.3 micron particles (90% efficiency).

AireTrust Nano-media KN95 Particulate Mask with 4C Air Inside

Personal protection

4C Air has collaborated with AireTech Clean Technology to produce the Nano-Media KN95 Particulate Mask with 4C Air's BreSafe nanofiber filtration media and filtration technology: a nanofiber-based particulate mask that can filter out 95% of dangerous particles, including fine particulate matter and harmful germs. It is designed for ergonomic comfort while meeting the high-quality needs of everyday personal protection.

  • Five-layered mask for multiple particle blocking sizes and comfort
  • High filtration efficiency (>95%) for 0.3 microns particles
  • Low breathing resistance compared to competitors
  • Certified KN95 (GB2626-2006, equivalent to NIOSH N95)

  • Shop Here

    4C Air Window Screen

    Home and commercial solution

    By integrating our nanofiber with perforated or mesh based materials, we have developed a new and innovative PM2.5 filtering window screen which has:

  • Up to 99% efficiency for particles of 2.5 microns
  • High optical transparency
  • Low air resistance

  • The filter is ideal for spring and fall ventilation, as it can also be used as a pollen filter. The product is not recommended to be used during high or dangerous pollution levels (AQI>200), when windows should be closed.

    *Efficiency is determined using TSI's standard CertiTest Filter Tester Model 8130A, rated for 0.3 micron particles (90% efficiency).

    Beijing smog by Kentaro Iemoto
    Wikimedia Commons

    Air pollution was linked to 6.5 million deaths in 2015…

    In growing countries like India, China, Pakistan, Bangladesh, Madagascar and Kenya, the researchers say that up to 1 in 4 deaths can be tied to pollution.

    Particulate Matter with diameter less than 2.5 microns (PM2.5) [mainly from fossil fuel burning and vehicular emissions] is the most consistent and robust predictor of mortality in studies of long-term exposure.


    4C Air has developed a method to mass produce nanofibers which are suitable for filtration. Roughly one hundred times smaller in diameter than the fibers in commercially available filters, the increased surface area to volume ratio makes them excellent at PM2.5 capture and filtration.

    These fibers have an ultra-low basis weight, are optically transparent, and have low resistance to air flow, making them ideal for innovative PM2.5 window screens and integration into personal face masks. We are also exploring integration into filters for HVAC and automotive exhaust.

    We are also developing fibers with high temperature stability, providing a potential solution for high temperature filtration.

    For more information or any inquries