One downside of many home air purifiers is that they produce ozone; a molecule consisting of three oxygen atoms, which happens to be a very unstable configuration. Ozone’s instability causes it to break down quickly, resulting in a stable pair of oxygen atoms and a very reactive oxygen free radical. These free radicals are extremely reactive and can cause lung damage and harm to other vital tissues in sufficient concentration; they have also been suggested to increase the risk of developing some cancers among other illnesses. Asthma sufferers should avoid ozone particles as much as possible because they can worsen the symptoms of the disease.

These home air purifiers don’t normally emit ozone in a quantity sufficient to cause harm to most people, but you will be able to smell the ozone in the air. This ozone performs a useful function by binding to many of the impurities in the air, including allergens. There are also home air purifiers which use electrically charged metal plates instead of ozone to remove airborne particulates like pet dander, pollen and other materials. Fans move the air through the system with impurities being trapped by the charged metal plates. With these home air purifiers, you need to clean the metal plates weekly.

An allergy relief air purifier is not going to make your allergies go away but you will feel better. By significantly reducing the amount of smoke, dust, pollen, dander and other allergenic particles in the air around you, you’ll have symptoms far less often. Home air purifiers vary by their capacity; a small air purifier does well for a 10’ x 15’ room, but if the space you want to use it in is much bigger than this, you’ll have to get a larger and pricier one.

Any home air purifiers you choose should have HEPA (High Efficiency Particulate Air) filters. A HEPA filter keeps particles pulled from the air from becoming airborne again, something which can be a problem with air purifiers that use metal plates to trap allergens and other impurities. HEPA filters are sometimes able to be washed but not always. These filters often last as long as the home air purifiers they are used with (3-10 years) while others need to be replaced every two or three years. One thing to keep in mind is that the price doesn’t always correlate to the quality or the useful life of HEPA filters.

If you’re sensitive to sounds, you’ll want to make sure that the air purifier you choose runs so quietly that you can’t tell if it’s on – quality home air purifiers are extremely quiet. The electricity used in some home air purifiers cause crackling and popping noises. Sometimes the fans in the home air purifiers are loud and can make it hard to hear the TV or to sleep. If you have a central HVAC system, you’ll definitely want to install quality air filters but in order to really get all of the allergenic matter out of the air you breathe, getting home air purifiers for your bedroom and any other rooms in your home where you spend a lot of time.

Aside from being thoroughly unpleasant to think they could be living in your carpets and bedding, dust mites are also one of the most common causes of asthma, eczema and an endless list of other inconvenient allergies. Technically it’s dust mites’ droppings rather than the actual mites that cause problems, as they are coated in an enzyme that is highly allergenic to over 20% of the population. Their food is the 50 million dead skin cells every human sheds each day, and it can be a nightmare getting rid of them completely. Tough, but not impossible. If you suspect mites could be living in your home, the most important things to remember are:

Keep it Clean – the most obvious way to stop dust mites is to get rid of the dust. They nest in ‘dust bunnies’ and in the carpet so regular hoovering, every day if necessary, will not only suck many of them out of the carpet but cut off the food supply to those that are left behind. Leave windows open whenever the weather is good enough as they don’t like sunlight, not to mention a healthy breeze will literally blow them away as they are so small!

Keep it Fresh –You might not think air quality would have much effect on dust mites considering they live in the carpet and furnishings, but in fact the right air conditioner could make all the difference. Even when you’re hoovering daily there is still time for skin cells and dust particles to settle and create new homes for mites. Installing an air purifier with a HEPA filter literally removes all particles larger than 0.0003mm from the air before they get the chance to settle, meaning less food for mites.

Keep it Dry – Dust mites thrive in conditions where the air is moist with a relative humidity (RH) of 50% or higher. Different people have different ideas of the recommended RH in a home and it varies depending on where you live, but it is usually around 45%. If the normal humidity level in your home is anywhere above 50% trying to reduce it is a good idea as this will not only stop the mites but can also improve the general health of the occupants. Basic things like keeping windows open when cooking or showering can make a difference but if the problem persists then using a dehumidifier is a quick and easy way to remove moisture from the air, maintaining the optimum RH and killing dust mites dead!

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 of ionic air purifiers fall squarely in this realm.

In this article, I am laying out the roadmap as I look into the 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 creation of a powerful invisible defence shield against airborne molecular contaminants is increasingly taking centrestage. 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. In active mode, the reactive agents are pushed into the environment with the impure air. 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.

Plasmaclusters of positive and negative ions encircle and latch onto harmful bacteria and viruses in a deadly grip. When clumping occurs, hydroxyl is produced. Hydroxyl, also known as nature’s detergent, is a powerful reactive species that destroys airborne particulates by plucking out hydrogen molecules from their organic structure. 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 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. 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. Negatively charged ions are naturally attracted to these particulates until they sink to the ground by sheer weight. 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.

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. Water droplets are splashed onto a metal plate where a small electric charge is applied. Large numbers of negative ions are produced as water droplets are split. 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. Applying a high voltage pulse to the electrode results in the production of millions of negatively-charged electrons. It is claimed that this method produces no ozone. 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. 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. The key reactive purifying agent is hydroxyl, nature’s detergent.

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. viruses and pathogenic bacteria) or non-infectious and non-contagious (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.

POC technology has been criticised for relying on hydroxyl which are believed to attack with equal tenacity the organic structures that make up molecular contaminants and our lung tissue, nose membranes and eye cornea.

Electrostatic Filter

This technology appears to have originated in heavy industries which produced abundant pollutants. The typical arrangement in an electrostatic filter ionic air purifier comprises a porous dielectric material sandwiched between two electrodes. A dielectric material does not conduct electricity while metallic electrodes are good conductors that transmit or receive electricity.

Impure air is drawn into the electrostatic purifier so that it passes over the dielectric material. Electrostatic electricity between the electrodes causes airborne particulates i.e.dust, smoke contaminants, etc, to adhere to the surface of the dielectric. Out of the other end of the purifier, cleaned air is recirculated.

Very often, an ion source is inserted before the electrostatic filter to 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. The safety issues of each technology will need much more investigation. I have also not examined in detail 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.

The Beginnings of the HEPA Air Purifier

The HEPA air purifier traces its origins to the year 1940. It was first produced at the time of the Manhattan Project, during which radioactive contaminants entered the atmosphere. As time went by, air purifiers, which originally didn’t utilize a filter, were continuously improved to address the need for better quality of air in our modern society.

Nowadays, you can find air purifiers in a variety of institutions like medical centers and industrial plants. The air purifiers have been embraced by a vast array of manufacturing and service industries, including pharmaceutical, aerospace, nuclear, health care and electronics.

This high functioning product boasts a 99.99 percent reliability rating, and has proven to be an extremely helpful piece of equipment. Take a look at the testimonials found in just about any air purifier review, and you’ll see that HEPA air purifier reviews show that they are highly regarded just about everywhere.

How Does it Work?

There are three steps in the HEPA process: interception, impaction and diffusion. Since they consist of randomly ordered fibers, they are highly efficient when it comes to their ability to filter out undesirable particles. They grab pollutants and all types of other unsafe elements which can cause a variety of allergies, ailments and diseases.

The first step is the capture of a stream of air within one radius. The air is trapped by the filters and so the process begins. The next step is impaction, whereby large molecules are filtered by the tiny fibers within the air cleaner. The molecules continually decrease in size as the air travels through the fibers contained in the system. Lastly, the air collides with other gas particles in a process called diffusion.

There are many uses for a HEPA air purifier system, the most important of which is the highly effective way it rids the air of allergens that we regularly breathe in. You can’t totally eliminate the contaminants in the air by using a HEPA air purifier, but you can definitely reduce them substantially.