An air purifier is an essential component to maintaining an allergen free and healthy home. The best in the market is an all around air purifier especially for those with severe allergies. There are those which are superb as a quiet bedroom air purifier and inexpensive to run. It has to be a good, economical and durable air purifier.
There are air purifiers offers the best products available to address asthma, allergy symptoms, whether you are in the market for allergy relief or simply looking for a cleaner home or office, you can comfortably buy from your local supplies store.
There are several basic technologies that are known to be effective in providing real improvement to office and home indoor quality. There is no best technology because each solves different problems. Filters effectively remove 99.97% of all particulates such as pollen and dust that pass through the filter, returning purified to your home or office.

Air Purifier Technology
Air purifiers employ what seems to be simple technology on the surface. Effective air purifiers draw from the room with a fan, clean the air, and send it back out into the room. There are a number of ways cleaning is performed while in the actual system. First there is adsorption.
Adsorption uses a media like activated carbon or zeolite. These media are porous so that the airflow is exposed to relatively large surface area. As the chemical contaminates come in contact with the media the chemicals combine the media and are thus removed from the room.
Adsorption will remove chemicals and some parts of tobacco smoke and odors but has little impact on particles. The second approach is mechanical filtering much like your furnace filter. In this case the room air is screened of particles however, the screen is very fine.
Most all of the high-end air purifiers use some type of pre filter in addition to the filter elements mentioned above. The purpose of the pre filter is to extend the life of the fine filter by removing large particles before they can get to the HEPA filter. You will typically find visible dust, hair, and lint in the pre filter.

Office and Home Air Purifiers - Efficiency:
Efficiency refers to the amount of air that is actually passed though the filter system of an air purifier. In typical home improvement store brand air purifiers a good percentage of the flow slips by the filter system and is propelled back into the room without being cleaned. Unfortunately the manufacturers are not required to state their air purifier efficiency.

Applications of Air Purifiers
The real key to addressing any allergen issue is the removal of the source of the pollutant or irritant if possible.
Asthma Air Purifiers - This is a tough medical condition with which to deal and we can only address the asthma that is induced by poor air quality not that induced by exercise or stress. The asthma triggering irritant may be either a particle such as pollen or a chemical or smell. Therefore, utilizes both mechanical and adsorption air purifier technology.
Pollen, Dust, and Mold Allergies - This is one of the most common applications for home air purifiers. If smells or odors also tend to trigger your allergy then you should consider using the units recommended for addressing the symptoms of asthma.
Pet Allergies - Since we are assuming you will not get rid of your pets we will emphasize the cleaning of their bedding and other items such as toys and play gyms to reduce the source of the pet material as much as possible prior to installing any air purifiers. Pets, particularly cats, tend to clean themselves by licking their fur.
Tobacco Smoke - The smoke from cigarettes and, even worse, cigars is a stew of gasses and particles. It is particularly hard to address with room air purifiers because the source is so active putting out so many pollutants in such a short time. Even if all of the room air went though the air purifier 6 times per hour a Cigar will still overwhelm the air purifiers until it is extinguished.