Air Purifiers are all the rage now, everybody has them and everybody sells them. There are Ionic Air Purifiers, regular filter Purifiers and HEPA filter purifiers.

the Journal of the American Medical Association now suggests that the air pollution existing today in the US raises the risk of lung disease to a point where more than half of the US population is breathing unhealthy amounts of air pollution.

More than 50 million Americans seem to be suffering from allergies and more than 20 million battle asthma.

There is such a thing as Sick Building Syndrome, a worldwide phenomenon, when chemical substances used in office construction such as glue, insulating materials, cardboard, and fiberglass are steadily released into the atmosphere from electronic equipment, carpeting, furniture and fittings.

That is why the air inside buildings or residential structures may be many times more polluted than the air outside, according to the EPA.

Because of all these reasons Air Purifiers have become very important. The different types of air purifiers include mechanical purifiers, electronic air purifying systems, hybrid purifiers and gas phase purifiers. Most of these systems remove particles and harmful toxins from the indoor air.

The HEPA Filter is a High Efficiency Particulate Arrested Filter designed to remove 99.97% of all airborne pollutants 0.3 microns or larger from the air that passes through the filter ( including tobacco smoke, household dust and pollen).

There are also filtering technologies that operate by using ozonation. The most popular air purifier on the market today uses ozone. These purifiers actually produce ozone which is an irritant that can worsen asthma and decrease lung function.

The removal of particles from the air is what is measured when the efficiency rate is trying to be achieved.

The fraction of particles that is removed from the indoor air being measured is what determines the amount of efficiency an air purifier possesses.

Air cleaners using mechanical filters or electronic technology can perform particle removal. Mechanical home air purifiers are units that can draw the indoor air through a metal or fibrous filter that is designed to trap the particles.

Because filters have different size pores they are able to catch these particles. is able to catch these particles with its different sized pores. Different types of filters may be pleated , square, round, with different levels of efficiency.

Mechanical filters in general are very efficient in eliminating contaminants from the air as long as they are cleaned regularly. There are 3 diferent types of electronic purifiers:

Electrostatic purifiers pull air into a chamber and charge the particles electrically. The air is then let through wafers which are negative ion generators, give particles a charge and cause them to stick to the nearest solid object.

These purifiers are not as effective as the other electronic or mechanical purifiers because they do not eliminate particles but move them to another location.

Ionizers do the same thing but create ozone which in itself may be bad for your health. Ozone is a lung irritant produced by ion generators and some other electronic air cleaners and ozone generators.

While indirect ozone production is of concern, there is even greater concern with the direct, and purposeful introduction of a lung irritant into indoor air. There is no difference, despite some marketers' claims, between ozone in smog outdoors and ozone produced by these devices. Repeated exposure to ozone pollution may cause permanent damage to the lungs.

Hybrid air cleaners use both mechanical filters and electronic technology in order to clean the air of particles. Ozone emissions may be present from the use of electrostatic air purifiers and negative ion generators. High levels of ozone may be harmful but cleaning the units as specified by the manufacturer may mitigate the possible bad effects of ozone to some extent.

Efficient Air Purifiers can cost anywhere from $500 to $1500 for a single room and a System to clean a whole house can easily run into the thousands of dollars.