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• TH E FI E L D C O N T R O L S C O M PAN Y •

THE FIELD REPORT

UV Air Purification

The Sun: Nature’s Outdoor Air Purifier

For years, scientists have known that one of the most effective air purifiers is natural sunlight. Not the light we see when we look out the

window, but the invisible "C" band, ultraviolet rays that make up part of the sun's light spectrum. UV-C light inhibits the growth and

reproduction of germs: bacteria, viruses, fungi & mold. The sun acts as a natural outdoor air purification system, controlling airborne bacteria

with ultraviolet rays.

Indoor Air: High Concentration Of Biological Contaminants

Biological contaminants in indoor air account for over 50% of home allergies, according to the World Health Organization. Asthma and allergy

sufferers must endure constant bombardment by molds, dust, and spores. Even worse, inhaling airborne bacteria and viruses can cause

sicknesses ranging from allergies to tuberculosis, and are actually the cause of death to an estimated 8.5 million people annually.

The sun’s UV rays must directly contact bacteria in order to affect them. This process does not occur indoors. The Environmental Protection

Agency reports that indoor air can contain up to 70 times more pollution than outdoor air. The air in a single room can contain hundreds of

thousands of infectious bacteria, viruses, fungal spores, and contaminants, which can only be seen with a microscope.

Facts About UV

Ultraviolet energy waves, invisible to the human eye, are lethal to the microorganisms found in indoor air. UV’s effectiveness is directly related

to intensity and exposure time. Also, to destroy microorganisms, UV rays must strike the contaminants directly. UV light penetrates the

microorganism and breaks down molecular bonds causing cellular and/or genetic damage. The germs are either killed or sterilized, leaving

them unable to reproduce. In either case, live bacterial counts can be significantly reduced and kept under control.

Filter Systems Alone Don't Solve the Problem

The majority of indoor air is conditioned by forced-air heating and cooling (HVAC) systems. Standard fiber air filters are entirely ineffective in

trapping germs, as most particles are simply too small, passing right through the porous filter. New, HEPA style filters will only capture air-

borne bacteria down to a certain size. These HEPA filters are nominally effective, trapping small airborne contaminates on the filter, creating a

breeding ground where germs can continue to grow and multiply.

HVAC systems are a dark and damp breeding ground for mold and bacteria, particularly at the system filter and air conditioning (A/C) coil.

The buildup of matter on the A/C coil and filter can significantly reduce the efficiency of the appliance as the airflow is constricted and

reduced. This means increased cost to the homeowner on top of the risks of airborne pollutants.

To reduce indoor airborne bacteria, contamination, and particulates, many health and environmental authorities recommend air

purification with ultraviolet energy.

Summary of content (5 pages)

PAGE 1
THE FIELD REPORT UV Air Purification The Sun: Nature’s Outdoor Air Purifier For years, scientists have known that one of the most effective air purifiers is natural sunlight. Not the light we see when we look out the window, but the invisible "C" band, ultraviolet rays that make up part of the sun's light spectrum. UV-C light inhibits the growth and reproduction of germs: bacteria, viruses, fungi & mold.
PAGE 2
Indoor Air Treatment With UV UV’s effectiveness in killing bacteria is directly related to a microorganism’s exposure time. Indoor air in a typical residential forced-air HVAC system will be recirculated over 50 times a day. With a UV generating lamp mounted in the HVAC duct, cumulative exposure can be very effective in controlling indoor bacteria. UV rays will also kill germs that breed in drain pans and A/C coils.
PAGE 3
Intensity Of The Light Diminishes Over Distance UV rays are predominantly emitted perpendicular to the surface of the lamp. In order to determine the intensity of ultraviolet radiation on a surface at different distances from a UV lamp, multiply the intensity of the lamp rating at 1 meter (microWatts per square centimeter) by the intensity factor opposite the distance selected as shown below. This table provides an easy method for quickly calculating ultraviolet intensity.
PAGE 4
Installation Locations Locating the UV lamp in the supply duct over the A/C coil is the first choice as this is downstream of the air filter, keeping the lamp clean. Also, the lamp will inhibit bacteria growth in condensation formed on the air conditioning coil, a prime breeding ground for bacteria, spores and viruses which can become airborne. Alternatively, install the UV device in the return air duct, preferably downstream of the air filter.
PAGE 5
Output Life It is important that lamps be replaced when the ultraviolet output falls below minimum requirements for protection. Even though a lamp may appear to be operating satisfactorily because it still maintains the blue visible glow, the ultraviolet output may be significantly reduced. To maintain maximum benefits, UV lamps should be replaced annually.