Air purifiers can also be used to reduce airborne pollutants such as pollen

An air purifier or air conditioner is a specialized device that eliminates pollutants in the atmosphere in a given room to enhance indoor air quality. These units are most commonly sold as being helpful to asthma sufferers and allergy victims and also in removing or decreasing second-hand cigarette smoke in a home or office. There are several distinct types of air purifiers, each designed for a particular kind of pollutant and intended for a particular room or area within a house or building. Many air purifiers can also control and filter water as well. Many newer air purifiers and humidifiers are electricity-powered. Some models require no special power source at all.

Air purifiers that generate ozone are often found in houses that have a number of occupants, particularly children who are very active in playing and engaging in outdoor activities. Ozone generators use of lamps to generate ozone at a high level, thereby killing airborne germs and pollutants. However, some ozone generators use of light in combination with an air purifier to kill more dangerous and larger pollutants. The two together are usually called an ozone generator.

Indoor air purifiers are designed to remove the threat posed by airborne allergens and pollutants. Examples of these include dust particles, pollen, mold spores, dust mites, dirt and other foreign matters. Indoor air purifiers are often combined with air filters that are used to remove the particles from the incoming ambient air before they are released into the room. In many cases, an indoor air purifier also includes an ozone generator to emit ozone in the room.

Air purifiers are also popular for eliminating unpleasant odors in a home or office space. Many people suffer from various types of odors that cause them to be uncomfortable. Some odors can even be hazardous to one's health. Air purifiers can eliminate these odors as well as many other types of unpleasant smells, such as that created by cooking.

Air purifiers can also be used to reduce airborne pollutants such as pollen, dust, cigarette smoke, mold, pet dander, dust mite particles, dirt, dust, and smoke. Air purifiers are generally powered by a chemical called activated carbon, which captures small particles in the air, such as pollen. The filters must be replaced on a regular basis in order to maintain effective operation. Other pollutants that can be removed with the help of air purifiers include volatile organic chemicals (VOCs), ozone, and other organic compounds. However, it is important to note that the efficiency of an air purifier will depend largely on the quality of the filters used.

Air purifiers are available in different sizes. There are light and heavy duty models, portable models, and filters suitable for ozone. Ozone filters are particularly useful because they do not allow particles to pass through. Air purifiers are also available in room size, portable, and custom fit options. Room size purifiers are recommended for rooms containing pets and children.