Maestro Reiki

Ionic Air Purifier Technologies – Who Is Telling The Truth?

Introduction

Ionic air purifiers hold the promise of clean air, purified of all known harmful contaminants that threaten our health. Naked eyes cannot see these harmful contaminants. Invisible ions battling invisible contaminants appears to make perfect sense. Intuitively, the logic appeals to me. But these days, finding a simple and quick solution is rare. Googling the subject unearths a ton of controversy. Even though I am tempted to quickly get an ionic air purifier to clean the air I breathe, it is clear that more time and effort is needed. Product safety must take precedence over effectiveness in choosing an ionic air purifier.

The recent China melamine saga that killed infants also is a timely reminder to us that in buying into any technology or any product, all claims by manufacturers and distributors must be screened to the fullest extent that our resources permit. This is even more critical when the key reactive agent is unseen to the human eye. Investigating ionic air purifier technologies falls within this ambit as the reactive agents are invisible ions.

This article is an overview of existing ionic air purifier technology in the marketplace. My back-to-basics approach is an attempt, as a layperson, to understand the science behind the technology. The creation of a powerful invisible defence shield against airborne molecular contaminants is increasingly taking centrestage. The prime threat being closely monitored by scientists all over the world is the avian flu virus.

Types of Ionic Air Purifier Technologies

Broadly speaking, air purification technologies can be deployed in either passive or active modes. Passive typically means that impure air is drawn into the air purifier for the reactive agents to work on before re-emerging as cleaned air into the environment. Conversely, in active mode, reactive agents are pumped into the impure air environment. Interestingly, marketeers betray their lack of confidence in their own ionic air purifier technologies by combining both passive and active modes.

In the global market today, ionic air purifier technologies include the following categories:

(A) Ion generator – positive and negative ions
(B) Ion generator – negative ions only
(C) Photocatalytic Oxidation (POC)
(D) Electrostatic filter
(E) Combos

Ion Generator – Positive and Negative Ions

This combination of positive and negative ions appears to show the most promise for the future of ionic air purifier technology. They have been named as plasmacluster ions by Sharp Corporation, the Japanese corporate powerhouse that invented them.

Sharp explains that the plasmacluster of positive and negative ions clump to harmful airborne bacteria and viruses. When clumping occurs, hydroxyl is produced. Hydroxyl, also known as nature’s detergent, is a powerful reactive species that plucks out hydrogen molecules from the organic structure of these airborne particulates thereby destroying them. This chemical reaction generates harmless by-products, the main of which is water.

A differential ion generator is used in this technology, comprising a positive and a negative ion generator which can be powered in alternate cycles to control the type of ions generated.

Advocates of the positive and negative ions combination claim that a balance of both these ion types is to be found in places like waterfalls and pristine forests, i.e. this is the actual state in nature. Adherents of the negative ions technology expound the view that negative ions dominate these natural habitats and that positive ions are harmful. In this regard, I have yet to find independent scientific studies as evidence for the contradictory claims of both camps.

Ion Generator – Negative Ions

The traditional ionic air purifier produces only negative ions. Currently, this technology dominates market share but it is under serious threat from Sharp’s plasmacluster positive and negative ions technology.

It is claimed that nearly all harmful airborne particulates like dust, smoke and bacteria etc have a positive charge. Negative ions from the air purifier attach themselves to these particulates until they get weighed down and fall to the ground. These impurities are simply removed by vacuuming. Weighing down the particulates does nothing to destory them, according to critics, and merely walking on them causes the air to be polluted again.

It seems that there are several ways to produce negative ions. It is crucial to know the various methods as each may have different by-products, some of which are harmful. These methods include:

(1) Water method – this employs what is known as the waterfall or Lenard Effect. Onto an electrically-charged metal plate, water droplets are splashed. Large numbers of negative ions are produced as water droplets are split. No harmful by-products result from using the water method to produce ions.

(2) Electron radiation method – this is based on a single negative discharge electrode needle. Applying a high voltage pulse to the electrode results in the production of millions of negatively-charged electrons. This process does not generate any ozone. This is due to the application of a “smaller” energy pulse.

(3) Corona discharge method – this is based on a dual electrode model, a sharp metal electrode and a flat electrode. High voltage is applied between the electrodes. The movement of electrons between the electrodes ionises the air in that same space. A criticism of this method is the production of harmful by-products like ozone and nitride oxide.

Photocatalytic Oxidation (POC)

This technology is commonly applied in a passive mode. Hydroxyl, nature’s detergent, is the key reactive agent in POC technology.

Germicidal ultraviolet (UV) light is commonly shone on a catalyst (usually titanium oxide) to produce hydroxyl, oxygen and peroxide, all of which are potent oxidising agents that are very effective at destroying the organic structure of micro-organisms and gaseous volatile organic compounds.

Complete and comprehensive action is the pillar of POC technology. Proponents of this technology claim that POC inactivates ALL categories of indoor pollution, including:

(1) airborne particulates i.e. dust, pet dander, plant pollen, sea salts, tobacco smoke, industrial and car pollution, etc

(2) bioaerosols i.e. contagious or infectious biological compounds (e.g. viruses and pathogenic bacteria) or non-infectious (e.g. non-pathogenic bacteria, molds, cell debris)

(3) volatile organic compounds (VOCs) i.e. gaseous chemicals or odours – benzene, styrene, toluene, chloroform, hexane, ethanol, formaldehyde, ethylene, etc, all common emissions from everyday products of our modern home.

Detractors of POC technology are wary of the inability of hydroxyl to distinguish between the organic structures of molecular contaminants and that of our nose membrane, lung tissue and eye cornea.

Electrostatic Filter

This technology appears to have originated in heavy industries which produced abundant pollutants. In the most common electrostatic filter arrangement, there is a porous dielectric material positioned between two electrodes. Dielectric materials do not conduct electricity while metallic electrodes are excellent conductors that transmit and receive electricity.

As impure air is drawn into the electrostatic purifier, it passes through the dielectric material which acts as a sieve. The electrostatic field created between the electrodes causes airborne particulates i.e.smoke contaminants, dust, etc, to stick to the dielectric surface. Purified air emerges from the other end of the purifier.

Very often, an ion source is inserted before the electrostatic filter to charge the airborne particulates. Charging the impurities make them adhere more effectively to the dielectric material.

Critics of this technology point to the production of harmful ozone in the ionisation process.

Combo Ionic Air Purifiers

To cater to the various adherents and critics of the diverse technologies, combos incorporate all or some of the above types of technologies. Combos may include:

(1) adsorptive materials such as activated carbon or oxygenated charcoal (known for its extremely porous large surface area) are added to POC technology to enhance the removal of VOCs;

(2) oxidizing catalysts like titanium oxide are coated on various components of all types of air purifiers to enhance VOC elimination;

(3) reducing catalysts such as manganese dioxide are coated near the exit outlets of many air purifiers to reduce reactive species like ozone and nitric oxide which may be harmful;

(4) generating ions by differing methods such as using microwave, UV light, radio frequency waves, and direct current;

(5) tweaking the specifications of any ionic air purifier technology so as to attain the well-known HEPA status without actually using HEPA filters.

Obviously, the process of selecting the most efficient and effective ionic air purifier involves analysing a deluge of information. And I have not even touched on the safety aspects of each technology. I will also be studying in greater depth the claims of each technology. I urge you not to rush out to get the latest air purifier for your homes, offices, factories, schools etc. Do your homework and check back here for updates as I continue to find the ideal ionic air purifier.

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