UV Lighting & 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 and 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 sickness ranging from allergies to tuberculosis, and are actual 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 only seen with a microscope. To reduce indoor airborne bacteria, contamination, and particulates, many health and environmental authorities recommend air purification with ultraviolet energy.

Facts about UV

Ultraviolet energy waves, invisible to the human eye, are lethal to the microorganisms found in indoor air. UV’s effectiveness is related directly to intensity and exposure time. In addition, 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 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 Do Not 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 airborne 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. 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 re-circulated 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. Properly positioned, an ultraviolet system can significantly reduce indoor air contamination and prevent the growth of new microorganisms. The treatment of indoor air with ultraviolet radiation has been successful in health care facilities, food processing plants, schools, laboratories and other applications. It is a safe, silent, and proven method of improving indoor air quality. Warning: UV lamps must only be operated inside metal ductwork where the light can be contained.

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. In addition, the lamp will inhibit bacteria growth in condensation formed on the air conditioning coil, a prime breeding ground for bacteria, spores and viruses that can become airborne. Alternatively, install the UV device in the return air duct, preferably downstream of the air filter. Install a UV device in both the supply (over the A/C coil) and the return is ideal for its cumulative effect.

Summary

With tighter home construction, indoor air quality has declined dramatically. Indoor air is laden with invisible bacteria, viruses, toxins and molds. Filtering systems offer little or no solution because these airborne contaminants are so small they pass through the filter or simply collect on the filter medium, creating a breeding ground. Re-circulated air contains millions of disease and allergy-causing microorganisms, which not only live in the air, but also are multiplying with each cycle through the system. Ultraviolet radiation (UV-C) replicates the natural outdoor purification system of the sun by destroying the allergy and disease-causing microbes living and multiplying in indoor air. Ultraviolet radiation is a safe, cost-effective method of purifying indoor air. By itself, or in combination with a HEPA or like-quality filter, it is the most effective way to reduce airborne bacteria and the health risks they represent. The result is a clean, safe, healthy home environment.

How Ultraviolet Is Helping Families and Schools

As reported in the HVAC Insider, third Quarter 2003 Magazine The Conley family of Brighton, MI are an average family living in an average home. The air inside their home was causing their family problems. Their daughter, Katie, suffers with allergies that were so severe she experienced interrupted breathing patterns and her parents had to sleep in her room to make sure she did not stop breathing. Attempting to eliminate the source of Katie’s allergies, they changed filters, pillowcases, bedding and considered removing carpet and draperies in their home. As a last resort, the doctor said the cat had to go. They had the heating ducts professionally cleaned and were about to get rid of the cat when they heard about the UV-Aire purifier. Within a few days of installation, Katie was able to sleep at night, her breathing patterns were normal, and the cat was able to stay. They were completely amazed. Katie improved 100%, is able to play sports and is enjoying improved overall health.

A new elementary school in Beulaville, NC is among the 20% of U.S. schools who have reported unsatisfactory indoor air quality that can affect the comfort, health and performance of students and staff. In one particular classroom, the teacher and students complained of an indescribable odor. The smell greeted us in the hall as we approached the classroom, reported the teacher. Both teacher and students had itchy throats and itchy, watery eyes. The carpet was ripped up and tile installed but did not help. The maintenance department installed a UV-Air purifier and the smell was gone within days. There are now plans to install additional units throughout the entire school system. An HVAC contractor in Pinckney, MI had personal experience with UV air purification. His teenage daughter had chronic allergies to pollen, dust mites and other indoor allergens since she was five years old. Allergy shots every other week and daily medication was prescribed, but no improvement was noticed. After the installation of a UV-Air purifier, her symptoms totally disappeared within two months. In the fall, her symptoms suddenly returned. They checked the UV lamp and discovered it had been unplugged when the furnace was serviced two weeks prior. The UV-Air purifier was plugged back in and within one week, her symptoms disappeared. The family figures they have saved about $1500 in doctor visits and prescription drugs. A Doylestown, PA resident used to take daily medication for allergies and was using a spray to prevent congestion at night. His HVAC contractor recommended installing the UV-Air and started noticing results in about two months. He was able to lie in bed at night and breathe easier without sprays and other medications. He was able to gradually decrease daily medication and now does not need any medication at all. In addition, his family began to notice that they were no longer susceptible to the common colds that passed through the area.