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An air ioniser (or negative ion generator or Chizhevsky's chandelier) is a device that uses high voltage to ionise (electrically charge) air molecules. Negative ions, or anions , are particles with one or more extra electrons , conferring a net negative charge to the particle.
An air purifier or air cleaner is a device which removes contaminants from the air in a room to improve indoor air quality. These devices are commonly marketed as being beneficial to allergy sufferers and asthmatics , and at reducing or eliminating second-hand tobacco smoke .
One of tallest (nearly 24 inches) and heaviest (17.5 pounds) air purifiers tested, the Winix 5500-2 Air Purifier is ideal for small-to-medium rooms (up to 360 square feet), with a True HEPA filter ...
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300 nm – greatest particle size that can fit through a HEPA (high efficiency particulate air) filter (N100 removes up to 99.97% at 300 nm, N95 removes up to 95% at 300 nm) [84] 300–400 nm – near ultraviolet wavelength; 400–420 nm – wavelength of violet light (see Color and Visible spectrum) 420–440 nm – wavelength of indigo light
This is a list of articles about prime numbers.A prime number (or prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself. By Euclid's theorem, there are an infinite number of prime numbers.
= milligrams of pollutant per cubic meter of air at sea level atmospheric pressure and T: ppmv = air pollutant concentration, in parts per million by volume T = ambient temperature in K = 273. + °C 0.082057338 = Universal gas constant in L atm mol −1 K −1: M = molecular mass (or molecular weight) of the air pollutant
Portable room air cleaners with HEPA filters can be used if ventilation is poor or outside air has high level of PM 2.5. [122] Air filters are used to reduce the amount of dust that reaches the wet coils. [citation needed] Dust can serve as food to grow molds on the wet coils and ducts and can reduce the efficiency of the coils. [citation needed]