Nissan Motor Co., Ltd. has developed a new type of high-performance filter using the anti-allergenic properties of natural grape seed polyphenol. The new filter is significantly more efficient in eliminating allergens that are the cause of pollen allergy. The filters will be introduced into Nissan’s range of compact cars in Japan beginning December 2006.
Conventional filters are designed to block mainly dust and pollen particles with a minimum size of 10 micron. This allows adequate removal of pollen in particle form, but it is not very efficient in blocking smaller diesel particulates (up to about 1 micron) or other allergens, particularly allergy-causing pollen, with a size of 0.3 to 0.5 micron.
Polyphenol has the ability to neutralize allergens of cedar pollen and dust mites, and Nissan’s researchers have taken advantage of this unique property to create a high performance filter using fiber impregnated with natural grape seed polyphenol*1. The three-dimensional molecule structure of natural grape seed polyphenol traps the allergen molecules and deactivates them by binding to the multiple -OH active groups that causes the allergy reaction. This action reduces the effect of cedar pollen allergens by 88 percent*2. or approximately five–fold improvement compared to monomeric polyphenol such as catechin*3. In addition, the antibacterial properties of natural grape seed polyphenol are about 1.5 -times better (reduction to 1/10,000 or less) than conventional filters*4.
Another important characteristic of the new filter is the fact that each fiber carries an electrostatic charge. As a result, the filter is capable of trapping other particles of similar size through its electrostatic property in addition to the removal and binding of allergens. When the air circulation in the cabin is set to re-circulation intake option (with fan speed set at the two setting), the particle count in the 0.5 micron range is reduced to 1/10 in under five minutes, or equivalent to 90 percent elimination.
With continual use for 15 minutes, elimination efficiency can reach as high as 99.5 percent. Through the adoption of the new high performance cabin air filter, Nissan expects to further improve passenger comfort and their surrounding environment in the passenger cabin.
Image of allergen neutralization through catechin
Image of allergen neutralization through grape polyphenol
*1: Joint development with Kikkoman Corporation and Toyobo Co., Ltd.
*2: According to research at Fukui University
*3: According to in-house research at Nissan
*4: According to research at Japan Spinners Inspecting Foundation
Source: Nissan Motor Co., Ltd. vom 2006-12-18.