09.26.08
Best Air Purifiers
Picking the best air purifier is a very difficult decision since the need of each allergy or asthma situation has different needs. Adding to this tough task is different allergens and different types of home pollutions are removed in different ways. Below are some comparisons of some of the more popular type of air purifiers.
Air Purifiers with HEPA (High Energy Particle Arresting) filters were originally developed for the atomic energy commission and are used in commercial clean rooms to remove particles of dust and other airborne pollution. This is a paper or polymer sheet with very tiny holes that allow airflow to pass though the material but not very much else. The holes are so small you need a lot of surface area for a reasonable amount of airflow to pass though the material. It is because of this that the medium is always folded in an accordion or zigzag fashion to get a lot of surface area in a small area. There is also a mixed version of the technology that one manufacturer uses where the holes in the HEPA filter are slightly larger to promote more airflow but the air is charged with electrostatic wands. Which then attracts any of the smaller particles that get thru the holes. HEPA Filters work well in the home for trapping particulates. The disadvantage is that the filters must be changed regularly (every 6-months to 5-years depending on the manufacturer). The review of any HEPA unit depends on the efficiency (how much air by-passes the filter), fan noise, filter life and price.