Did you know that up to 80 per cent of the dust in the air you’re breathing right now (assuming you are sitting inside) is made up of dead skin? Human flesh is the most common form of dust in the air, and makes up the bulk of what’s known as “indoor air pollution”. So far, over 350 different types of indoor air pollution have been identified. Some common ones include pet dander, viruses, molds, pollen, cleaning chemicals, and solvents from furniture, construction, and clothes.
Experts say that when children are exposed to large quantities of this dust at an early age there is a spike in the instances of asthma and allergies. In fact, indoor air quality has become a hot topic over the past couple years with the discovery of “sick building syndrome”. This is a term used to describe the effects that molds, viruses, and gases have on people who spend all their time in offices or otherwise indoors, and is responsible for all kinds of maladies.
Ultimately, the only real cure for sick building syndrome is a good dose of clean, fresh air. Barring that, there are many different Ionic air filtration and air purification devices on the market these days, each meant to eliminate the threat that indoor air pollution poses.
But just what is the difference between an air filter and an air purifier? The basic home or office air filter is simply a panel that fits over the intake of the buildings furnace or air vents. Simple ones are made from fibreglass or polyester, and allow for the passage of air but trap large particles of dust. These filters are often placed in front of fans because the large particles of dust can accumulate over time and eventually clog up the machinery. These basic filters serve no real protection, but they do protect the machinery from burning out.
Some types of filter can be washed and reused, but the majority of them are meant to be thrown away after they become too dirty to use anymore. Then they are simply replaced with a new one.
The problem with these basic filters is, of course, that they are meant to mainly protect the furnace or air conditioner that they are used on. They may collect dust and smoke, and pollen (also good if you want to live an allergy-free lifestyle), but they do nothing against harmful moulds and bacteria. They are equally useless against airborne viruses.
Giving Dust a Jolt of electricity is another form of air filtration system is the needle ionizer and the plate ionizer, also known as Electrostatic Precipitators. These devices use electricity to filter out all of the smoke and dust out of the air. Plate ionizers use electricity to give the incoming air a static charge. The air then is passed through a series of metal “plates” that contain the opposite charge of the air surrounding it. This causes all of those charged particles to be attracted to the plates, and in this way the air is effectively purified. This can be a very effective way to clean the air. Many plate ionizers are small and quiet enough that they can be installed in several rooms of your house. They are also good for furnaces and cooling systems as the do not impede the flow of air the way traditional filters do.
Ionic air purifier use high voltage electricity to create negative electrons. These electrons run up the length of a pointed spike, or needle, where they stream into the air and attract oxygen molecules. At this point, they become negative ions. Negative ions occur naturally in the air we breathe, and they are quite harmless. These negative ions attach themselves to airborne particles. When enough negative ions attach to a particle, it gets too heavy to float in the air and drops to the ground (a process known as agglomeration), effectively getting it out of regular air circulation.
Both plate and needle ionizers use high voltage to clean the air, which causes an inherent shock danger for anyone who needs to work on it. Also, in the case of plate ionizers, the collecting plates can be a breeding ground for moulds and bacteria, and should be cleaned fairly regularly.
Needle ionizers also have the additional problem of their negative ion field. They cause the surrounding air to carry a negative charge while the walls and furniture around it still carry a positive charge. Essentially, it uses any surrounding surface as a plate ionizer, causing particles to stick to any surface. This effect is known as “black wall”, and it can be frustrating to keep the area around the Ionic air purifier clean. In both cases, electrostatic precipitators do nothing for odours and merely serve to collect airborne viruses and bacteria instead of killing them.
The corona discharge purifier is another way to purify the air. These air purifiers use electrically created ozone to purify the surrounding environment. One way that ozone is created is when electricity is used to bond oxygen molecules together. In its natural state, oxygen atoms will pair up to form molecules (O2).
Ozone is created in nature by lightning. You may have been near a lightning strike at some point in your life and smelled the fresh, clean smell that lightning leaves behind. That smell is actually ozone that was created by the static discharge. Ozone carries a highly unstable bond and reacts with nearly everything it encounters. In the case of ozonating air purifiers, most of that interaction takes place with indoor air pollution. Ozone molecules float in the air until they come in contact with a foreign particle. At that point, the extra oxygen atom splits off and attaches itself to the particle.
The introduction of this new oxygen atom causes a tiny cellular explosion, transforming the foreign particle into hydrogen and carbon dioxide. The remaining oxygen molecules are left as pure oxygen (O2).
There are literally thousands of different pollutants that ozone will react with to duplicate this process. It is one of the only purification systems that actually dissolves odours (as opposed to simply masking them) and can render microbial bacteria, moulds, and viruses sterile. Once sterilized, the colony is greatly reduced within a matter of hours.
Ozone has even been proven as an effective food preservative! A corona discharge air purifier uses electrical blasts of 5,000 to 10,000 volts in order to create ozone. The ozone then cleans the air and makes everything smell fresh and clean. The drawbacks to a coronal discharge purifier are that they are expensive to run and they can cause black wall. It takes a lot of electricity to create your own little thunderstorm!
Additionally, the amount of ozone they create fluctuates depending on the amount of oxygen in the air, and several harmful compounds can also be created when ozone is produced. Substances such as nitric oxides have been shown to irritate the respiratory system, and that’s not what someone hoping to live allergy-free wants at all. Another air purifier that creates ozone is the ultraviolet air purifier. These devices use shortwave ultraviolet light to bombard oxygen molecules in the air. These molecules, once exposed to the UV rays, quickly reform themselves into ozone molecules.
UV light is an effective method for air purification because the ozone obliterates most of the contaminants in the air. Also, harmful microbes, spores, and bacteria that are exposed to UV light become unstable and mutated. These mutated creatures are unable to reproduce, making them short lived.
Again, there are drawbacks to this type of air purifier. Many of the dangers associated with coronal discharge air purifiers are also related to UV air purifiers. They can create fluctuating amounts of ozone, and the bigger lamps used in large rooms can create far too much ozone.
One of the most widely used filters on the market for the home or office filtration system is the HEPA filter. Used for decades by the military and medical professions, HEPA filters have become synonymous with clean air. HEPA stands for High Efficiency Particulate Air. HEPA filters were originally developed by the military during The Manhattan Project (the US military program during World War II that developed the atomic bomb). HEPA filters are basically made up of a special paper-like glass fibre sheet pleated in a “V” pattern with corrugated aluminium separators between the pleats. This is bonded onto a sturdy base, forming the core of the filter. HEPA filters can filter out 99.7 per cent of all particulates in the air. They effectively capture all large particles and many of the small ones. In fact, a HEPA filter is designed to capture particles in the air no smaller than 0.3 microns in diameter.
However, it is important to note that a HEPA filter is just that-a filter. It is not a purifier. Although it may capture some spores, moulds, and viruses, it will not neutralize them. HEPA filters also cannot be re-used. They must be replaced, and that can be an expensive prospect. HEPA filters also rely on motorized fans, and that can make them noisy. Since they need to make air flow through them to filter it, they are fairly ineffective in large spaces. The filters themselves are also brittle, and can easily be damaged during installation. Despite its drawbacks, the HEPA filter is the best air filter on the market and easily out-performs its competitors.
The Air Filter and Purification markets are expected to skyrocket in the coming years with the sharp increase in terrorist attacks around the world. Some analysts predict that the “clean air” market could be worth $6.2 Billion by 2006. Good news indeed for the makers of these products. It is also good news for the consumer, as constant competition can only serve to improve these products.
Hopefully, this article will do its part by helping you decide what kind of filter or air purifier is right for you.
