Efficacy of NQ500 Air Treatment System

An often asked question is are there any studies to substantiate the effectiveness of the NQ500. No clinical tests have been performed on the NQ500, however, numerous studies (see below) have been conducted on Ultraviolet Germicidal Irradiation (UVGI) and HEPA filters. The Centers for Disease Control and Prevention (CDC) states the following: "Air Disinfection can be accomplished by UVGI and by filtration of air, such as through high efficiency particulate air (HEPA) filters."

The use of ultraviolet light and HEPA filtration are the only methods of air cleaning recommended by CDC. This is based on CDC acceptance of the established efficacy of both UVGI and HEPA filtration for the control of airborne infection.

The NQ500 from NQ Industries, Inc. uses both UVGI and HEPA filtration.

UVGI: UVGIÕs ability to kill micro-organisms is well documented and accepted by CDC. It depends on radiation intensity, exposure duration, and organism susceptibility. The attached chart shows the UV dose necessary for complete destruction of certain bacteria and virus. Mycobacterium tuberculosis requires a dose of 10,000 mw-sec/cm2 , E.Coli 6,600 mw-sec/cm2 and Infectious Hepatitis 8,000 mw-sec/cm2 .

With three 36" lamps and the given air flow, the NQ500 produces 46,480 mw-sec/cm2 (see attached calculation) when the lamps are new, more than three times the kill dosage required for TB. Even after a year of continuous use and assuming a 24% degradation of UV output, the lamps still produce more than 35,324 mw-sec/cm2. The formula used for this calculation is an industry standard for light efficiency and is a result of years of research.

Maximum UV output is assured through the use of two prefilters. The first filter (25-30% ASHRAE) removes larger particles and the second filter (30% ASHRAE) traps very fine particles.

HEPA FILTER: As a final filter, the NQ500 uses a 12" x 24" x 12" HEPA filter rated at 99.97% (DOP method). The typical TB bacteria ranges in size from 1 to 5 microns and is therefore easily trapped by this media. HEPA filters have been used for many years in ORÕs and "clean" room applications. The CDC specifies their use where recirculation of air is used or where air is being exhausted from an isolation room.

Studies on UVGI: Riley 1957, 59, 62, 89, 88, 89.- Stead 1989 - McLean 1961 Studies on HEPA: Sherertz 1987,94 - Rhame 1984,95 - Opal 1986

Copyright 1997 by NQ Industries, Inc.