Cat Q&A

Posts Tagged ‘ionic air purifier’

Safety tops all criteria in the selection of an ionic air purifier for use in the home, office, factory or school.

Existing ionic air purifier technology, regardless of whether they originate in North America, Europe, Japan or China produce a primary beneficial reactive agent.These reactive agents are known variously by names like negative ions, bipolar ions, plasmacluster ions and so on. Their main role is to eliminate airborne contaminants in our indoor living environment. Much has been written on the efficacy of these reactive agents in destroying contaminants. What we do not know is whether these same potent reactive agents also cause harm to delicate human tissues such as those that line our breathing passages from the trachea to the lungs.

Whether by design or otherwise, there is also an information void about whether there are other by-products and if these are harmful to fragile human tissues as well. In the industry, however, it is has been established that current ionic air purifier technology inadvertently results in the production of by-products that may, in sufficient concentrations, prove harmful to human tissue. One of the main by-products is the infamous ozone, which in high concentrations has been tested to be harmful to human tissues.

Accordingly, for the ionic air purifier user, the issue of safety has to be addressed from these two perspectives:

(1) Potential harm from the beneficial reactive agents, and

(2) Potential harm from the unintended by-products.

We have done intensive web research on these two important perspectives. The reports are featured on Ezinearticles.com.

Don’t miss these 2 in-depth Ezine articles. To read, click on the Ezine Author Badge on The Ionic Air Purifier Blog.

Subject to their terms and conditions, Ezinearticles.com allows publishers to freely reproduce these two articles. So help yourself, publish the two articles on your websites as a complete set, via these links:

(1) Beneficial reactive agents

(2) Unintended by-products

In addition, keep updated with our progress as we research other aspects of the very broad and constantly changing field of ionic air purifier technologies.

Introduction

Ionic air purifiers hold the promise of clean air, purified of all known harmful contaminants that threaten our health. Air is made impure by substances unseen by our naked eye. Invisible ions battling invisible contaminants appears to make perfect sense. Intuitively, the logic is appealing. Unfortunately, there is no simple solution as google throws up an avalanche of controversy within seconds. Obviously, I must resist the urge to go by intuition and grab the first ionic air purifier that I lay hands on. 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. This is especially so where the key reactive agent is invisible to the naked eye. My investigation of ionic air purifier technologies falls within this realm, as the reactive agents are ions that are invisible to our eyes.

This article is an overview of existing ionic air purifier technology in the marketplace. As laypersons, I believe we have to adopt a back-to-basics approach to try and understand the technologies. 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 dominant global health threat under the scrutiny of scientists 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. In passive mode, impure air is drawn into the air purifier for 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. It is not unusual to find combinations of both passive and active modes in many ionic air puriifers.

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.

Plasmaclusters of positive and negative ions encircle and latch onto harmful bacteria and viruses in a deadly grip. When this happens, hydroxyl is produced. Known as nature’s detergent, hydroxyl is a powerful reactive species that plucks out hydrogen molecules from the organic structure of these airborne particulates, thereby killing 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. 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 technology appears to have the main market share currently but is facing a serious challenge 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. Regular vacuuming removes these impurities from our environment. Weighing down the particulates does nothing to destory them, according to critics, and merely walking on them causes the air to be polluted again.

Apparently, there are a number of ways to produce negative ions. It is critical to know the various methods as each may have different by-products, some harmful and some which are not. These methods include:

(1) Water method – this employs what is known as the waterfall or Lenard Effect. Water droplets are splashed onto a metal plate where a small electric charge is applied. The charge splits the water droplets resulting in the production of a large number of negative ions. Proponents of the water method believe it to be free of harmful by-products.

(2) Electron radiation method – this is based on a single negative discharge electrode needle. The simple application of a high voltage pulse to the electrode results in millions of negatively-charged electrons being produced. An advantage of this method is that no ozone is produced. It is claimed that this is because a “smaller” energy pulse is applied.

(3) Corona discharge method – this is based on a dual electrode model, a sharp metal electrode and a flat electrode. An extremely high voltage is then applied to the two electrodes. This causes the movement of electrons between the electrodes thereby ionising the air in between them. This method has been criticised for the production of harmful by-products like ozone and nitride oxide.

Photocatalytic Oxidation (POC)

This technology is commonly applied in a passive mode. It relies on the production of the powerful reactive agent, hydroxyl.

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.

The key pillar of POC technology is its comprehensive coverage. 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 chemicals or odours – benzene, toluene, chloroform, ethanol, formaldehyde, 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. The typical electrostatic filter ionic air purifier includes two electrodes sandwiching a porous dielectric material. The dielectric material impedes electrical conductivity whilst the electrodes efficiently conduct 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 between the electrodes causes airborne particulates i.e.dust, smoke contaminants, etc, to adhere to the surface of the dielectric. From the other end of the purifier, purified air emerges.

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.

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. The safety issues of each technology will need much more investigation. I have also not examined 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.

To easily receive updates on new articles, subscribe to The Ionic Air Purifier Blog today.