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Dan Buglio is a Certified Indoor Air Quality Professional by the:
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Below is a comparison of various indoor air quality systems and methods of purifying air by utilizing filter-less systems of Ozone and UV light:
General
Ultraviolet Light and Ozone receive a lot of attention concerning indoor air quality. Both are nothing new. They have been used for decades in hospitals, medical applications and the food industry. This technical overview will outline each of the technologies and discuss the pros and cons of each.
UV-C – Germicidal Lamps
These are rapidly becoming very popular as an easy fix for the air conditioner coil mold problem. This is the most prevalent cause of the building mildew smell you get when you enter an air-conditioned sick building. UV-C (254nm) lamps are basically similar to sun lamps and are typically only effective on microbes that pass by within a few inches of the lamp or areas where the light is shining directly on for extended periods of time, such as the air conditioner coil (see article in HVAC News – yellow highlighted).
Pros:
Low cost, easy installation and effective on suppressing mold growth on the coil.
Cons:
Not effective at killing airborne mold unless numerous lamps are used (see article) only effective on the surface of the coil that is in direct light. This leaves much of the coil with no treatment. Does not provide ongoing room protection. Most UV systems install a glass UV mercury bulb without protection from breakage. A broken bulb could release mercury, a potential environmental and health hazard. Minimum of two lamps must be used to cover at least one-quarter of the coil surface (the upper half of the outer coil). For one-half coverage, three to six lamps must be used. 100% coverage is not practical.
UV-C – Ozone Lamps
UV lamps in the 185nm range produce low-level ozone, just as the sun does, which is very effective in odor microbial reduction and VOC’s.
Pros:
Low cost, easy installation, and effective on mold, smoke, odors and bacteria. The ozone gas travels through the house to provide ongoing treatment, unlike the UV-Germicidal Lamps where only the air that passes within inches of the bulb is treated.
Cons:
Ozone is a concern to some people. Improper systems could produce ozone levels exceeding Federal guidelines. Ozone does not work on all odors and VOC’s. Most UV systems install a glass UV mercury bulb without protection from breakage. A broken bulb could release mercury, a potential environmental and health hazard.
Corona Discharge Ozone Systems
These systems simulate lightning with a corona electric arc or spark. Strong ozone is produced by converting the oxygen (O2) to ozone (O3).
Pros:
Low cost. Ozone effective on odors, bacteria, VOC’s and mold.
Cons:
Air is 80% Nitrogen and 20% Oxygen. These units convert Oxygen to Ozone. They also convert the Nitrogen to Nitric Acid and Nitric Oxide, which causes maintenance problems due to corrosion. They produce high concentrations and levels of ozone, usually over Federal safe limits and airborne Nitric Oxide. These systems typically will require expensive monitors to control ozone levels. Also, arcing (sparking) can be a noise and safety problem.
Note: Corona Discharge Ozone Units should never be used for air purification in occupied areas, as they will usually exceed Federal safety limits of ozone.
UV Catalytic Oxidation Systems
This system utilizes a Titanium grid as a catalyst for UV-C (254nm) germicidal light. Air that passes through the grid and comes in contact with the catalyst is purified by Hydroxyl Radicals that are formed on the Titanium grid. Also, the UV-C light rays kill microbes that pass by them.
Pros:
Effective on the air that passes through the system for mold, bacteria and VOC’s.
Cons:
Expensive, large, substantial installation, and not effective on odors. Only treats the air that contacts activated target surfaces as it passes through the unit. Most UV systems install a glass UV mercury bulb without protection from breakage. A broken bulb could release mercury, a potential environmental and health hazard.
AHPCO™, is an Advanced Hydrated Photocatalytic Oxidation technology
Basically, it is a broad spectrum high intensity UV light, targeted on our patent-pending quad-nano Xtreme™ quad metallic catalyst, in a low-level ozone and moist atmosphere. This creates an advanced oxidation of friendly oxidizers. Unlike ozone, these oxidizers are safe, but yet aggressive at killing mold, bacteria, viruses and more. They also effectively neutralize odors and VOCs. Once they have done their job they revert back to oxygen and hydrogen. AHPCO technology has been successfully used in water, air, food and laundry applications.
Pros:
Low cost, low maintenance (every three years), and easy installation. Not only does this process treat the air that passes through the device, it sends low-level ozone (.02 ppm), hydro peroxides and super oxide ions into the room for complete coverage.
Note: The Federal limit for ozone devices is .04 ppm.
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