Ionic Air Purifier Technologies - Friend or Foe?
Introduction
Ionic air purifiers hold the promise of clean air, purified of all known harmful contaminants that threaten our health. The harmful impurities in the air are not visible to our naked eye. Invisible ions battling invisible contaminants appears to make perfect sense. I find the intuitive logic appealing. Unfortunately, there is no simple solution as google throws up an avalanche of controversy within seconds. It is quite clear that the urge to rush out and buy an ionic air purifier must be suppressed at the moment. Effectiveness is important but safety is paramount in the criteria for selecting an ionic air purifier.
The recent China melamine saga that killed infants also serves as a 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. Where the reactive agent is invisible, it becomes even more critical to focus on it. Invisible ions produced by ionic air purifiers are clearly in this category.
This article is an overview of existing ionic air purifier technologies in the global marketplace. Trying to understand the science behind the technologies seems to be the logical place to begin searching for the ideal ionic air purifier. The current key trend appears to be the creation of a potent invisible defence shield against airborne molecular contaminants that threaten our well-being. 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 mode technologies incorporate means by which impure air is sucked into the air purifier for reactive agents to work on before being re-introduced into the environment as cleaned air. 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. Developed by Japanese ingenuity, Sharp Corporation to be exact, they are known as plasmacluster ions.
Positive and negative plasmacluster ions actively surround harmful bacteria and viruses in a deadly embrace. When clumping occurs, hydroxyl is produced. Commonly known as nature’s detergent, hydroxyl is a powerful reactive species that destroys airborne particulates by removing hydrogen molecules from their organic structures. Harmless by-products, mainly water, are generated by this chemical reaction.
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 real state of the natural environment. Proponents of negative ions believe that negative ions dominate the environment in these natural habitats and even insist that positive ions are harmful. As I progress with my research, I shall be looking for independent scientific studies that support either of these two opposing views.
Ion Generator - Negative Ions
The traditional ionic air purifier produces only negative ions. This method seems to dominate market share in the industry but is coming 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. Vacuuming removes these neutralised impurities and therefore protects us from them. Critics of negative ion technology charge that the weighed down particulates are not destroyed and the mere act of walking around the room kicks them back into the air that we breathe.
In addition, there appears to be several methods of producing the negative ions. This is important because different methods produce different by-products, some of which may be harmful. These methods include:
(1) Water method - this employs what is known as the waterfall or Lenard Effect. Onto a metal plate that is electrically-charged, water droplets are splashed. This simple action results in the splitting of water droplets, causing the production of large numbers of negative ions. It is claimed that no harmful by-products are produced by the water method.
(2) Electron radiation method - this is based on a single negative discharge electrode needle. Millions of negatively-charged electrons are produced when a high voltage pulse is applied to the electrode. It is claimed that this method produces no 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. An inherent weakness 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. biological compounds that may be infectious or contagious (e.g. pathogenic bacteria and viruses) or non-contagious and non-infectious (e.g. non-pathogenic bacteria, molds, cell debris)
(3) volatile organic compounds (VOCs) i.e. gaseous odours and chemicals - toluene, chloroform, hexane, ethanol, formaldehyde, ethylene etc, all common emissions from everyday products of our modern home.
Critics of POC zoom in on the power effects of hydroxyl, claiming that they cannot differentiate between the organic structures that make up molecular contaminants and our lung tissue, eye cornea or nose membranes.
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.
Contaminated air is drawn into the electrostatic puriifer and made to pass over the dielectric material which acts like a sieve. The electrostatic field created between the electrodes causes airborne particulates i.e.dust, smoke contaminants, to stick to the surface of the dielectric. Purified air emerges from the other end of the purifier.
Frequently, an ion source is planted just before the electrostatic filter to electrically charge the airborne particulates. The impurities, now carrying an electrical charge, stick more effectively to the dielectric material.
Criticism of electrostatic filter technology focuses on ozone as a by-product, commonly assumed to be produced in all ionisation processes.
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. I have barely skimmed the surface of the safety issues of each technology. I will also be studying in greater depth the claims of each technology. So before you put your money down for any air purifier in your homes, offices, schools, etc, check back here for updates as I continue my quest for the ideal ionic air purifier.
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Ground-breaking Plasmascluster Ionic Air Purifier Decimates Bird Flu Virus
Sharp Corporation issued a seemingly ordinary press release on 27 August 2008. But I believe the information therein will one day gain global prominence! Incorporated in its ionic air purifier, the Plasmacluster Ion Technology (more on this in a later post) has just been scientifically proven to be 99.9% effective in eliminating the bird flu virus known as H5N1.
As we have been constantly reminded by the press, bird flu is the prime suspect to cause mankind’s next pandemic. Pandemic does not just sound terrifying. It is. That’s when a highly contagious and deadly virus goes global, in a very negative sense. The worst pandemic on record was the Spanish flu in 1918 which is believed to have killed 50 million people worldwide! That deadly killer flu was confirmed on 5 October 2005 by the World Health Organization (WHO) to be caused by H1N1, a bird flu virus.
Red Alert! Time to PANIC?
Not now. WHO statistics (updated up to 10 Sep 2008) tracing back to 1996 when the H5N1 virus first surfaced in China shows a relatively low death toll of 245. So what’s the fuss? Scientists monitoring the virus fear that it may mutate into a form that transmits from human to human. As I write, there has been only one probable case of human-to-human transmission recorded in Thailand in September 2004. Without a doubt, there will be global pandemonium if the dreaded virus mutation happens.
As the threat grows day by day, countries around the globe are conscientiously preparing for the worse (more on this in a later post). As protectors of our families and loved ones, we should start doing some homework too.
Ok, so what’s all this got to do with Sharp’s ionic air purifier. Is it not just another ordinary ionic air purifier? Yes, because it takes care of the usual pollutants (dust, dirt, smoke, dander, pollen, cuisine odors, pet odors, allergens etc) that contaminate the air that we breathe and live in. But if we can get protection from all these and more in one ionic air purifier, especially one that is a tested defense shield against a potentially deadly virus, why not? The complete package is promised in Sharp’s Plasmacluster Ion Air Purifier.
The next obvious question for the value-conscious, would be “yes, that makes a whole lot of sense but at what cost”? Here again, Sharp claims that it’s at no extra cost! Sharp contends that it is cheaper than any other competing ionic air purifier when measured over 5 years. Value for money grabs my attention anytime! How is it possible in this nothing-is-for-free world?
Yes, its possible, claims Sharp. For instance, in its Plasmacluster Ionic Air Purifier Model FP-N40CX, Sharp contends that it is undoubtedly better value for money as there is no filter replacement costs for the first 5 years. Upfront costs at US$399 for the Sharp model is higher than the typical competitor’s US$160. But the latter requires annual filter replacement costs of US$100, adding to a total cost of US$560 over 5 years.
If you have relevant data, be it on Sharp or the competitors, I would greatly appreciate your input. Feel free to drop me a note if you have actual data.
My next step will be to learn as much as I can about the Sharp Plasmacluster Ion Technology. The time to research is now, while bird flu is still not quite at pandemic proportions.
It’ll be way too late when that hits. Experience is a good teacher. It was like a horror movie that ran for months. Paranoia abounded in crowded places even as people commuted to work on buses and MRT trains. Taxis cruised empty as stories were told of the infected travelling in them to hospital. It was near pandemonium in many Asian cities as pandemic fears took hold. SARS! Four letters that struck terror in Asia. The SARS (severe acute respiratory syndrome) virus started spreading from Asia, infected 8,096 people around the world, resulting in 774 fatalities. As always, being prepared is half the battle won.
Watch this space as we track exciting developments in our pursuit of safe, pure and clean air with nothing more than an ionic air purifier.
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