Antiallergenic efficacy of filter media
Each day we inhale around 12,000 litres of air and remove 24 % of the oxygen it contains. We enrich exhaled air with carbon dioxide by a factor of 100, which is produced as a waste product of our energy metabolism. With 4%, this carbon-dioxide concentration is around a factor of 40 higher than the guide values recommended for room air. Rooms in which people (or other living beings) stay, therefore require high air exchange rates. This situation is particularly applicable to the relatively small interiors of motor vehicles.
Ventilation systems for vehicles
To ensure healthy carbon dioxide concentrations, ventilation systems for vehicles are designed so that the interior air is exchanged with "fresh ambient air" up to 200 times per hour. Natural external air can also contain various constituents, which many vehicle occupants can find extremely disturbing. These include airway allergens. In Germany around 15 % of the population suffer from an allergy known as "hay fever", 8.6 % of the population have bronchial asthma and react particularly sensitively to airborne irritants. The most frequently occurring airborne allergens are released by the pollen of several flowering plants. The pollen grains are comparatively large. They can therefore be separated out by filters very effectively. The allergy-triggering constituents of pollen on the other hand are far smaller. These are mostly enzymes of the pollen cells, which are only a few nanometres large. While pollen mainly causes allergy problems seasonally, spores of mould fungi and bacteria occur in the air all year round, and can also release allergens. However, virtually all allergens released by pollen and microorganisms have all kinds of different protein structures. This enables filter media to be equipped with biocatalysts, which change the structure of protein molecules so that they lose their allergy-inducing properties.
Test: antiallergenic efficacy of filters
The anti-allergenic efficacy of appropriate filter media can be verified. To do this, the media with the allergens to be tested are impinged with concentrations similar to those in practice and the efficiency of the allergen elimination is determined. Allergen-specific, highly sensitive immunological detection methods are used for the verification. bifa performs corresponding tests for filter manufacturers and other interested parties.