An air purifier is a device, which helps to free air from contaminants. The environment researchers claim that the air inside the house is dirtier than the air outside the house. Thus the popularity of sir purifiers increased. Air purifiers are beneficial to those who suffer from allergies and asthma. Even those who want to reduce second hand smoking use air purifiers. Allergens, that cause allergies, come in the form of dust, pollen, from pets and mold spores. It is essential to purify the air in your home from hazardous smoke particles and airborne gases.

There are various techniques of purifying the air with the help of air purifiers. Mechanical filters, use of absorbents like charcoal, electrostatic charges or ionizers are some of them. The other setups that are required are germicidal UV light and the emission of ions into the air. These ions react with the contaminants and make them harmless enough to breathe.

Many asthma medications that asthmatics take are reactive since they are taken to relieve asthma attacks (generally caused by environmental triggers). Removing environmental triggers such as airborne allergens and contaminates will decrease asthma problems, enabling a reduction in medication.

There are several factors that a consumer looks for while selecting an air purifier. They are visual appeal, noise level and frequency of filter replacement. There are different types of air purifiers.

· Home Air Purifiers - Protect your home from airborne pollutants. It is Perfect for asthma, smoke, pet dander, mold, or other home pollutants.

· HEPA Air Purifiers - HEPA purifiers are time tested air purification solutions that offer one of the best filtration systems for removing airborne particulates and organics. HEPA filters are specially made high grade filters which enable it to captured 99.7% of contaminates and particles that are 0.03 microns and larger in size.

· Ionic Air Purifiers - Ionic purifiers filter out small particles such as dust, smoke or pollen, and pump many negative ions into the air to provide optimal clean air performance. Studies show that a room with high concentration of negative ions promotes health, helps with sleep, tension, exhaustion, depression, allergies, exhaustion and many other ailments.

· Commercial Air Purifiers - Commercial purifiers are geared towards larger square footage applications and high pollution zones. They work well for large enclosed areas.

· Ultraviolet Air Purifiers - UV light tends to break down organic compounds extremely well. Using ultraviolet light, these UV air purifiers sanitize bacteria in the air.

The CADR, or Clean Air Delivery Rating, is a standardized indicator of how well the air purifier can function as compared to the others. The higher it is, the stronger is the power of purification. They are rated by the Association of Home Appliance Manufacturers based on the stringent requirements as produced by the association.