Strange but true. It is very, very difficult to find well-organized, properly documented scientific research about the technologies behind ionic air purifiers, a multimillion dollar global industry!
Strange because if the science is solidly grounded, I would expect any manufacturer of ionic air purifiers to trumpet the scientific basis of their brand. I would expect them to expound on the efficacy and effectiveness of their unique technology. Even more so, I would expect them to profusely assure users that their technology is perfectly safe, that they kill microbes but are perfectly harmless to human beings. Sadly, my expectations are not met.
True because I have spent countless hours looking for scientific technical papers supporting the technologies behind existing ionic air purifiers that are on the market and yet I have very little to show for it. Whether deliberate or not, marketeers of ionic air purifiers simply do not bother to put up scientific papers on their websites. Where they do, they make no distinction between safety, efficacy and effectiveness of their specific brands. The scientific references are mentioned only in brief and do not provide enough detail for study by the serious prospective purchasers of the particular air purifier. It is as if manufacturers do not expect anyone to question and scrutinize their products!
Inaccessible Scientific Research
Where I have stumbled upon relevant scientific research papers on the web, they are not readily accessible as they typically come at a prohibitive cost, being charged on a per article basis! I suppose if I am an entrepreneur looking to manufacture a new ionic air purifier I would be willing to invest in the hundreds and possibly thousands of technical papers indicated at some scientific journal websites. But I am only looking for a reliably safe product to buy for my personal use!
It is unfortunate that the scientific world is also commercially driven so that research of great importance is not made freely available to all who are interested or who need to know.
Nevertheless, though my head is still spinning from the deluge of inconclusive and confusing web data, my search for the ideal air purifier continues, along these criteria:
(1) Safety – the ionic air purifier technology must not cause any bodily harm to users;
(2) Efficacy – the ionic air purifier technology has been tested in the laboratory to really work on the basis on some thorough scientific research;
(3) Effectiveness – the ionic air purifier technology has been successfully transplanted from the laboratory into an appliance that will deliver the same results in a user setting i.e. home, office, factory, school etc.
In this article, I want to concentrate on the safety of ionic air purifiers, a factor which I believe overrides the other two criteria of efficacy and effectiveness. There is no point having something that works wonderfully in eliminating microbes but is so powerful that it harms our health. Two important questions need to be answered:
(1) Do the purported beneficial active agents of ionic air purifier technologies cause harm to human tissue? Are negative ions, bipolar ions, hydroxyl radicals, Sharp’s patented plasmacluster ions or whatever name they go by, safe?
(2) Do the unintended by-products of the ionic air purifier technologies cause any harm to human tissue? By-products include ozone and nitric oxides that are highly reactive and known to be harmful in high concentrations.
Beneficial Active Agents – Do They Harm Human Tissue?
No scientific data is available on the web on whether negative ions, bipolar ions, hydroxyl radicals, plasmacluster ions etc are safe in that they do not harm human tissue. There is plenty of data that demonstrate that these active agents effectively eliminate microbes, a subject which I will deal with in a later article. Here I am concerned that the touted potency of the active agents are equally destructive on fragile human tissue. Why is there a paucity of scientific data when millions of dollars are spent by consumers on ionic air purifiers every year?
After extensive but fruitless web searches, I did the next logical thing – ask the manufacturers of ionic air purifiers! From a few enquiries, the answer slowly became clear – the scientific data exists but manufacturers do not want to make them public lest they incur the wrath of animal welfare groups! Is this a real fear or are they hiding some unpleasant truth about their product?
Googling “animal testing” immediately threw up the huge controversy surrounding the use of animals in testing the safety of products meant for human beings. A case in point would be that of Huntingdon Life Sciences, a UK research company that conducts safety testing of commercial products, pharmaceuticals and home appliances. To this day, there is much conflict between testing companies and animal welfare groups. No wonder the cloak of secrecy by ionic air purifier manufacturers who are likely to conduct safety tests using similar testing companies.
Documented Animal Testing
A chance web search result helped me to better understand the animal testing controversy. The safety tests mentioned on the website related to a liquid product, not directly related to any ionic air purifier technology. The liquid is applied onto furniture and other household fittings. In the explanation of one of the benefits, it is claimed that when ultra-violet light in sunlight shines on the liquid, hydroxyl radicals and superoxide ions are released into the air hence destroying any microbes like bacteria, viruses and mold that may be present.
To prove that the liquid is harmless to humans, four categories of safety tests were performed on mice, guinea pigs and rabbits (please be warned that you may find the next paragraph offensive and you may wish to skip to the next paragraph).
(1) Test for acute oral toxicity – the liquid was orally fed to mice;
(2) Test for primary skin irritation – the liquid was applied onto deliberately abraded skin of rabbits;
(3) Test for skin sensitivities – the liquid was injected under the skin of guinea pigs;
(4) Test for mutagenicity – the liquid was applied to salmonella bacteria to ascertain if they caused mutation in the bacteria nuclei so as to ascertain if the liquid has the ability to cause cancer.
Pretty grim and repulsive stuff! I feel so even though the reports indicate that the tests were conducted in accordance with the Organization of Economic Cooperation and Development (OECD) Guidelines for Chemical Testing. I can begin to empathize with the animal welfare camp about such safety testing. Fortunately, for this liquid product, all the animals (even the salmonella bacteria) were found to be unharmed by its application.
This brief insight into animal testing explains why manufacturers of ionic air purifiers refrain from publicizing or even making mention of such tests when they are conducted.
Despite this concern of manufacturers, my web searches have revealed footnotes for certain brands whereby they indicate that safety tests have been conducted on the active agents. In searching for my ionic air purifier, I would be looking for such footnotes. I would expect that no animals had been harmed or the purifier would have no good reason to be on the market for human beings. I would also ascertain that the safety testing was conducted by reputable institutions that are accredited as GLP (Good Laboratory Practice), a set of principles issued by the OECD to recognize organizations which comply with strict scientific testing standards.
In the final analysis, does this mean that there is really no safety testing for the effects of active agents on human beings who use ionic air purifiers? Hardly, if you think about it. All the users become testers, having unknowingly volunteered by the act of purchasing one and using it!
Unfortunately, all we will hear on maufacturers’ websites would be glowing testimonials of the benefits of the purifier. Such testimonials, while helpful, come under the cloud of cherry-picking i.e. only the positive ones are featured. To be considered solid scientific proof that the active agents cause no harm to human tissue, the users’ operation of the ionic air purifier would have had to be subject to very stringent testing criteria and parameters of a GLP laboratory.
It would appear that this is an issue that will never be properly resolved. The only comfort for me is that many other products on the consumer market are sold in the same manner, purely on the good faith of manufacturers and considered safe until proven otherwise.
Safety – Second Aspect
In a future article, I shall discuss the second aspect of safety. Quite apart from the active agents, human tissue may also be harmed by potential by-products, deliberate or unintended, of ionic air purifiers.