Indoor Air Quality

 

This section contains quick explanations and criteria to help you  decide what filtration method is best for a given problem. You should be  familiar with the pros and cons for all the filtration and purification  methods listed below.

Filters are the most common filtration method. In general,  filters must permit some pollutants to pass with the airflow. The higher  the efficiency or density of the filter, the lower the airflow and  higher the restriction to the blower.


HEPA Filters

HEPA  

Description

HEPA stands for high efficiency particulate air filter.  HEPA filters utilize a powerful blower to force the air through a very  tight membrane to achieve high efficiency particulate filtration. 

Pros:

They are very efficient in the filtering of air that passes through the filter. They filter to .03 micron.

Cons:

They require filter changes. The filter can act as a  breeding ground for bacteria, mold and fungus. They do not remove odors,  gases, pesticides, viruses, and many bacteria. They reduce airflow due  to the tight pores of the filter. They are generally not used in central  systems, and sold as stand-alone units only.


Carbon Media Filters

Carbon Media  

Description

Carbon filters consist of carbon impregnated filter  fabric or granulated carbon. These filters usually have a foam or fabric  filter to hold the media. Carbon has the unique capability of acting as  a physical filter trapping particulate, and on a chemical basis by  reacting with some odors and some of the heavy gases. 

Pros:

Absorbs odor, absorbs some gases, filters particulate, installed in central or individual rooms.

Cons:

Requires frequent changes, acts as a breeding ground for  microorganisms, can easily become blinded and ceases functioning. They  reduce airflow.


Fiber/Foam Filters

Foam  

Description

Fiber or open-cell foam filters rely on the air passing  through a matrix of foam cells or fibers of fiberglass, wire, plastic or  cloth. Typically, these filters only stop medium to large particulate. 

Pros:

Low cost, low air resistance, installed in central units.

Cons:

They only filter the air that passes through the filter.  The particle build-up can act as a breeding ground for bacteria. They  only filter medium to large particulate.


Electrostatic Precipitators

Electro Static  

Description

Electrostatic Precipitators have been used by industry  for many years to clean up smokestack emission of particulate. They  operated by electrically charging a field between metal plates. The air  is charged with an electrical charge similar to static electricity. The  charged particulates collect and coagulate on a second set of charged  plates where they build up and fall to a collection tray. 

Pros:

They are very effective on removing smoke from the air  that passes through the filter. They do not reduce airflow as most other  filters do. They can be installed in central units or in each room.

Cons:

They require frequent cleaning. They only filter the air  that passes through the filter. The particle build-up can act as a  breeding ground for bacteria.


Negative Ion Generators

Negative ION  

Description

Negative ion generators have been used by industry for  years to remove particulates from the air and to neutralize the effects  of excess positive ions. Negative ions are produced electrically and  travel through the air until they attract airborne particulate and  coagulate the particulates until they are too heavy to drift and settle  to the floor. 

Pros:

They are very effective on removing smoke from the air.  They travel throughout the entire room and purge all the air of  particulate, not just the air that passes through a filter.

Cons:

They drop the particulates to the ground. They must be in each room as the ions cannot effectively travel through HVAC ducts.


Ozone

Ozone  

Description

Ozone is a gas of oxygen ⎯ an oxygen molecule containing  three atoms instead of two, like the oxygen we breathe. The extra atom  of ozone is known as a loose radical that looks for organics to attach  to and thereby oxidize. Ozone is known as a friendly oxidizer due to the  fact that it reverts back to oxygen after oxidation occurs. 

Pros:

Ozone is an oxidizing gas that travels throughout the  room and oxidizes all organics. Ozone can neutralize odors and gases.  Ozone destroys microorganisms and does not reduce airflow. Ozone units  can be installed in central units or in each room.

Cons:

Ozone has no effect on particulate solid particles. Ozone exposure can be very dangerous at high levels.


Ultraviolet (UV) Light

UV LIGHT  

Description

Ultraviolet light rays have been used as a sanitizer by  the medical profession for years. Ultraviolet light can also sanitize  air that is passed directly in its path with the proper exposure times. 

Pros:

Ultraviolet light can destroy bacteria, fungus, molds and some gases. It does not reduce airflow.

Cons:

Ultraviolet light has no effect on particulate, needs  direct close contact with a calculated exposure time, Ultraviolet light  rays must be shielded from human exposure. UV Light has little to no  effect on the conditioned space.


Photohydroionization

Photohydroionization  

Description

An advanced oxidation technology patented by RGF  utilizing broad spectrum HE/UV light targeted on a quad metallic target  that produces Hydroperoxides that reduce microbes and gases in the  conditioned space. 

Pros:

A broad scope of oxidizers makes it extremely effective on a larger number of microbes and gases.

Cons:

Little effect on airborne particulate.


REME+

REME+  

Description

A unique combination developed and patented by RGF® that  uses a Charged Advanced Oxidation Plasma to provide continuous  purification with the ability to increase the efficiency of removal of  .03 micron particulates with standard media filters up to 73%.  Filtration can be increased to 93% with RGF REME+ Grounded Collector. 

Pros:

All the benefits of Photohydroionization with the added benefit of increased efficiency and particulate removal.

Cons:

Must maintain Grounded collector or filter.

Technology Comparison

Below is a chart that illustrates the effectiveness that various  industry products, including the Guardian Air and REME in combating  indoor air pollutants. As you will see, only the REME provides whole  home coverage for all three types of pollutants.

When considering only Microbials and Gases, besides the REME, no  other solution is as effective as the Guardian Air. In independent  laboratory tests, the Guardian Air has inactivation rates of over 99% in  a matter of hours for the most common and deadly bacteria, viruses and  mold.