Electrostatic control of domestic dust and allergen particles for improved air quality

Indoor air quality is an important issue, as exposure to indoor allergens has been associated with recent increases in the prevalence of allergic disease. Reduction of indoor allergen levels can therefore play an important role in the overall management of these patients. Reviewed here are two new electrostatic techniques for controlling domestic dust and allergenic particles. A technique to improve the removal of airborne allergens has demonstrated enhanced precipitation of particles by charged liquid sprays. Charged sprays can be produced by maximising the shearing of electrical double layers during atomisation of liquids from domestic pressure-pack (PP) devices. Electrostatically charged sprays removed up to 45% of the total mass of airborne dust particles. The effect on small particles (<2.0 μm) is most significant, the concentration of these being reduced by 73% by the charged spray, compared with just 59% by the equivalent uncharged spray. The removal of dust and allergen particles from normal carpets during vacuuming can be enhanced by the application of an electrostatically charged carpet care powder. Carpet powders, of the type used to deliver a fragrance to a domestic carpet, can be triboelectrically charged during delivery to above 1 x 10(-4) C/kg. It has been found that when this charged powder was applied to carpets, up to 99% of dust was removed, 15% more than when no powder was applied. Application of a standard, uncharged powder resulted in significantly less dust being recovered. It was proposed that the charged powder particles attract dust and allergen from within the carpet pile, and that these large agglomerates were more efficiently removed by vacuum cleaning. These novel techniques for dust and allergen particle control in the domestic environment represent new applications for electrostatic technology. They come at a time of increased public awareness and concern for indoor air quality, providing potential tools for allergen mitigation in the management of allergic disease patients