What Does
Air Filter Mean?
An air filter is a type of screen installed in heating, ventilation, and air conditioning (HVAC) systems to clean the air by capturing airborne particulate matter and certain microorganisms. These filters work through physical or chemical processes that may involve fibrous pleated paper, foam, cotton, ionizers, activated charcoal, absorbents, or catalysts.
Air filters can capture dusts, powders, pollen, mold spores, fibers, and germs, among other things. Removing these from the air can make breathing more comfortable, remove unpleasant odors, and protect the health of building occupants.
Safeopedia Explains Air Filter
HVAC systems with air filters are used in residential and commercial buildings, hospitals, and public facilities. They are the first line of defense against a variety of airborne contaminants.
How Air Filters Work
Most air filters work by drawing in the surrounding air and passing it through the fine openings of the filter medium. Any particles larger than those opening are then trapped by the filter medium and separated from the passing air.
The quality and type of filter media used will determine the size of particles that will be captured. The filtration efficiency of the air filters also increases as particles form a layer in the upstream side of the filter media, which aids in screening other particles.
The filter media has to be cleaned periodically and replaced when needed to prevent it from clogging and restricting airflow, which can decrease its efficiency.
Types of Air Filters
Popular types of air filters include:
- High-efficiency particulate absorption air (HEPA) air filters absorb and clean 99.97% of airborne particles that are 0.3 micrometers or larger, which are particularly disruptive for asthma patients
- Ultra-low particulate air (ULPA) filters are 99.9995% effective in removing particles of 0.12 microns and larger
- Ionizer air filters use ions to attract particles and dust from a distance by magnetizing and neutralizing them
- Activated charcoal air filters are effective in filtering fumes, smokes, and some gaseous odors
- Germicidal ultraviolet (UV) air filters remove germs and viruses using specialized UV lamps
- Ozone generator air filters generate ozone gas to kill airborne germs (not recommended for residential use as it can irritate the lungs)
- Portable air filters can be used to clean the air in smaller rooms