Types of Air Sanitation

There is a wide range of devices that are promoted to clean, sanitize or sterilize the air. They range in use from personal individual use to devices that claim to clean the air in entire buildings. These devices are either freestanding personal air cleaners (PAC’s) or part of the central HVAC system, or “whole building” approach. The devices use one or a combination of, HEPA Filters, electrostatically charged filters, carbon filters, elite filters, ozone generators, UV lamps, charged plates, negative or positive ion generators, and photocatalytic oxides such as TiO2. Most devices on the market have at best testing documented for particulate (dust) removal using the limited performance measurement called CADR, a measure of dust, pollen and smoke removal only.

Ultraviolet Light (UV)

AiroCide^® Photocatalytic Air Purification Systems uses ultraviolet light primarily to energize the catalyst and activate the hydroxyl radicals that chemically react with organic compounds. In traditional UV applications Ultraviolet light has been placed within the air return duct of a central HVAC system or used as and element of a PAC. One or multiple UV lights are used to kill passing or trapped microorganisms. Accepted UV research shows there is generally insufficient energy or “dwell time” to kill microorganisms. The passing air simply moves too fast. An exception is if the UV light were aimed directly at the coil of an HVAC system, it would then kill ONLY pathogens on the surface of the coil not in the air.

HEPA Filters

AiroCide Air Purifiers do not rely on filter media to trap, contain or hold pollutants based on particle size or composition. High Efficiency Particulate Air or High Efficiency Particle Arrestor (HEPA) filters are used to reduce the number of contaminants in indoor air. A true HEPA filter will arrest or stop 99.97% of all particles 0.3 microns or larger. The limitations of HEPA filters include leaking (bypass) when used in vacuums; high initial and replacement cost, regular maintenance, and reduced airflow due to clogging. They cannot be added to existing central HVAC systems without special modifications to the HVAC blower system and they do not eradicate viruses, gases (VOC’s) or odors. Many so-called HEPA filters sold to the public are not "True HEPA" certified (they use the name "HEPA" for marketing purposes, some as low as 5% HEPA, which means they only remove less than 5% of what particles are in the air).

MERV Filters

Pleated MERV filters and pre-filters are used as central HVAC filter elements. Most will remove approximately 95% of particles 10 microns and larger. These filters are not able to collect microorganisms or viruses and have no effect on VOC’s.

Carbon Media Filters

Because AiroCide breaks apart the chemical bonds of organic materials, neither particles nor gases (VOC's) are absorbed or masked temporarily. Carbon, or charcoal, filters will capture odors and some VOC’s. Because they work like microscopic sponges, they do release (or "degas") odors and/or VOC’s back into the environment with just the slightest temperature change. These gases and/or odors can be concentrated when degassed by the carbon filters in much higher concentrations than were in the original air.

Electrostatic Precipitators

AiroCide Air Purifiers do not utilize ionic charging technology to capture pollutants on plates, grates or grills. Electrostatic precipitators use a process of electrically charged plates that attracts dust. Some microorganisms can be collected along with the dust. The collection area (plate) must be kept clean for efficiency. These Electrostatic precipitators generate Ozone.

Ozone Generating Devices

Unlike random and released gaseous hydroxyl radicals generated by ozone-making mechanisms, the hydroxyl radicals created during photocatalysis within AiroCide Air Purifiers remain surface-bound and totally contained within the reaction bed inside the system. Ozone makes up the largest percentage of what we call outdoor air pollution. The American Lung Association states that human exposure to ozone should be “none” and OSHA issues a standard for ozone levels of a maximum of 0.08- parts per million (ppm) exposure*. Even so, ozone generators are sold today as ion generators, plasma, cold plasma, happy ions, negative ions, atomic oxygen, and pure air (used with UV to produce hydroxyl radicals, sometimes referred to as photocatalytic ionizing.) The ozone destruction mechanism uses gaseous hydroxyl radicals, compared to surface-bound ones created in photocatalysis. Ozone’s gaseous hydroxyl radical randomly attacks anything organic that it happens to collide with, including humans. Ozone cannot be safely used around humans in concentrations high enough (ppm) to destroy microbes. Marketers today are quick to circumvent the current standards however EPA, OSHA and FTC are beginning to focus on the problems and will develop much more stringent enforcement policies.

* in an 8-hour work period while doing heavy labor.

Other Photocatalytic Oxidation Methods

AiroCide Air Purification patented technology utilizes a nanoparticle science to make a titanium oxide membrane that is photocatalytically active, which also binds to the applied surface(s) without delaminating. Other attempts at using Titanium Dioxide (TiO2) coated materials that claim oxidation or pathogen destruction have proven ineffective. The intended catalysts in these cases are either not photocatalytically active and/or delaminate easily.