Minimizing pathogenic bacteria, including spores, in indoor air.* The earth has a natural background electrical field, which usually varies from about 150 to 200 volts per meter. * In indoor spaces, the natural background field is distorted by the electrical characteristics of materials in equipment, furniture, walls, clothing, and carpets. * The electrical fields generated by computers and other electronic equipment, and the electrical fields generated by power lines in walls, also distort the background field. * These factors create a complex three-dimensional web of voltage gradients often referred to as electrical field lines. * Electrical fields, rather than air currents, are the primary determinant of small-particulate motion in rooms. * Small particulates tend to move along the electrical field lines and be deposited on people and objects. * Relatively few small particulates are returned to air ducts; thus relatively few reach air filters. * As small particulates age, however, many collide, forming larger particulates. * This process is called coagulation coagulation (kōăg'y  lā`shən), the collecting into a mass of minute particles of a solid dispersed throughout a liquid (a sol), usually followed by the precipitation or .
* Coagulated co·ag·u·late v. co·ag·u·lat·ed, co·ag·u·lat·ing, co·ag·u·lates v.tr. To cause transformation of (a liquid or sol, for example) into or as if into a soft, semisolid, or solid mass. v.intr. particulates have a large enough cross sectional area to be entrained by air currents. * The coagulated particulates thus tend to be returned to the ducts. * Experiments were conducted to assess whether aerosolized Adj. 1. aerosolized - in the form of ultramicroscopic solid or liquid particles dispersed or suspended in air or gas aerosolised gaseous - existing as or having characteristics of a gas; "steam is water is the gaseous state" bacteria, including spores, respond like particulate contaminants to electrical forces in indoor air. * The experiments used two different genera and five different strains of bacteria, including spores. * Micrococcus luteus was used as a surrogate for Gram-positive cocci cocci /coc·ci/ (kok´si) plural of coccus. cocci [L.] plural of coccus. , because it is similar in size, shape, and cell wall composition to staphylococci, streptococci Streptococcus (plural, streptococci) A genus of spherical-shaped anaerobic bacteria occurring in pairs or chains. Sydenham's chorea is considered a complication of a streptococcal throat infection. , and enterococci enterococci bacteria in the genus Enterococcus. . * Spore spore, term applied both to a resistant or resting stage occurring among various unicellular organisms (especially bacteria) and to an asexual reproductive cell produced by many unicellular plants and animals and by all plants that undergo an alternation of forming and vegetative Bacillus subtilis were used as surrogates for Gram-positive bacilli such as Bacillus anthracis. * It was found that bacteria of different sizes and shapes respond like particulate contaminants to electrical field lines. * They also respond like particulate contaminants to procedures designed to accelerate coagulation. * These results suggest an approach to minimizing contamination in indoor environments and reducing nosocomial infections. * They also have implications for protection against intentionally introduced pathogens, including Bacillus anthracis. |
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