The Science

Poor indoor air quality is a result of the ineffective “Corridor Ventilation Strategy” which has been replicated since the 1960ʼs in thousands of buildings across North America.

Door Filter™ technology provides a simple, elegant and cost-effective solution.

Typical solutions are either ineffective and highly energy consuming or invasive and cost-prohibitive – for example, the installation of separate, suite-by-suite ventilation systems.

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    lab_results_iconWith Door Filter, we’ve selected a filter medium that strikes a balance between ensuring maximum air flow while capturing the majority of particulate that would otherwise flow into your home.

    This is important as the provision of fresh air is a basic requirement in our homes while the presence of particulate in the air we breathe can trigger lung damage.

    In particular, exposure to allergens from house dust mites can be a contributing factor in the development of asthma as well as a cause of its symptoms.  Other allergens from pollen, molds, animal dander etc. can cause asthmatic symptoms.

    The following graphic explains the relative size of these common household allergens in microns (um).  The average human hair is 150 microns.  Its size has been magnified in the legend to the right so that the much smaller particle types can be seen.  For instance, bacteria, light dust and animal dander are between 1 – 5 microns, whereas dust, plant spores and mold are between 5 – 10 microns:

  • 150 150 Microns
    Average Human Hair
    25 25 Microns
    Lint, Particles Visible to the Naked Eye
    10 10 Micron
    Average Dust, Plant, Fertilizer, Pollen
    5-10 5-10 Microns
    Average Dust, Plant Spores, Mold
    1-5 1-5 Microns
    Bacteria, Light Dust, Animal Dander
    0.3 0.3-1 Microns
    Bacteria, Tobacco and Cooking Smoke, Metallic Fumes

 

Door Filter is designed to capture these types of allergens and a range of particulate types of similar size.

For instance, a soiled Door Filter was tested and lab results indicated the following types of particulate as shown in the table below. The right hand column shows the typical diameter of these types of particulate; namely: 0.6 – 6.34 microns.

Particle Type Captured Symbol Size (microns, um)* Relative Size of Particulate
Dolomite Mg 5-106.34µm Average Dust, Plant Spores, Mold
Calcite Ca 1-54.64µm Bacteria, Light Dust, Animal Dander
Quartz Si 1-53.90µm Bacteria, Light Dust, Animal Dander
Sodium Chloride Na 1-53.78µm Bacteria, Light Dust, Animal Dander
Rust (Iron Oxides) Fe 1-53.42µm Bacteria, Light Dust, Animal Dander
Organic / carbon OC 0.30.6-1.9 um+ Bacteria, Tobacco and Cooking Smoke, Metallic Fumes

* Aerodynamic mass median diameter (MMD) as established by Milford and Davidson (1985), Table II on page 1255
+ OC is mainly found in smaller particles as noted in paper by Offenberg and Baker (2000), Table 2 on page 1513

“As [North Americans], we spend over 90% of our time indoors, so the quality of our indoor air should be a concern to all of us. Given the amount of time that we spend indoors, it should be a concern for everyone that poor indoor air quality can trigger asthma and allergies.”

Author's imageHealth Canadahttp://www.hc-sc.gc.ca/
  • Corridor Ventilation Strategy

    Millions of North Americans have made the choice to live in rental or condominium apartments buildings. Public policy makers encourage this as an excellent option for the environment as it supports effective land, energy and water use. Despite these benefits, there is a long list of common complaints among apartment dwellers related to indoor air quality. This is a result of the ineffective “Corridor Ventilation Strategy” which has been replicated since the 1960’s in thousands of buildings across North America (and internationally).

    Essentially, fresh air is pumped into common corridors and then makes its way into each apartment unit through the spaces around a unit’s entry door (between the door and its frame).

  • While air enters into a unit, so may a host of other irritants like dust, odor, noise, pests, light, and cooking fumes. These system failings are well documented through academic research.

    Typical solutions are either ineffective and highly energy consuming or invasive and cost-prohibitive – for example, the installation of separate, suite-by-suite suite ventilation systems.

    By contrast, the Door Filter™ technology provides a simple, elegant and cost-effective solution that works with and enhances the existing corridor ventilation system. Door Filter™ is an innovative, new, North American-designed filtration product that improves the indoor air quality within apartment units as it reduces a variety of air pollutants while still allowing proper air movement from the corridor to the apartment unit. Door Filter™ is a dense ABS extension that is fitted and secured to the bottom of the inside face of an apartment entry door and lined with a door sweep (to seal off units). A removable multi-stage air filter (charcoal, particulate and microbe) is placed inside the device. Small openings in the ABS allow air to pass through the device and internal filter promoting clean airflow into the apartment unit. The system has the added benefit of decreasing noise and eliminating light transfer from the corridor into the suite. In short, with Door Filter™, you can now add fresh air to the many environmental benefits of apartment living.

     

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  • “It is well known that poor indoor air quality increases the severity and the frequency of respiratory symptoms experienced by asthmatics.”
    Pollutants that can aggravate asthma include the following:

    • Biological pollutants such as mold and house dust mites.
    • Irritating chemical pollutants such as nitrogen dioxide, ozone and formaldehyde.

    Author's imageHealth Canadahttp://www.hc-sc.gc.ca/