Learn How to Improve Your Home Air Filtration System
There are several types of air cleaning devices available, each designed to remove certain types of pollutants. The different options of air cleaning devices all fit in 3 main categories as follows:
- Particle Removal
- Gaseous Pollutant Removal
- Pollutant Destruction
Partical Removal Devices
Two types of air cleaning devices remove particles from the air, mechanical air filters and electronic air cleaners. Mechanical air filters remove particles by capturing them on filter materials. For example, this category includes high efficiency particulate air (HEPA) filters. Electronic air cleaners such as electrostatic precipitators use a process called electrostatic attraction to trap charged particles. They draw air through an ionization section where particles obtain an electrical charge. The charged particles then accumulate on a series of flat plates called a collector that is oppositely charged. Ion generators, or ionizers, disperse charged ions into the air, similar to the electronic air cleaners but without a collector. These ions attach to airborne particles, giving them a charge so that they attach to nearby surfaces such as walls or furniture, or attach to one another and settle faster.
Gaseous Pollutant Removal Devices
Gaseous pollutant removal cleaners remove gases and odors by using a material called a sorbent, such as activated carbon, which adsorbs the pollutants. Typically, these filters remove one or more gaseous pollutants from the airstream that passes through them. Because gas-phase filters are specific to one or a limited number of gaseous pollutants, they will not reduce concentrations of pollutants for which they were not designed.
Pollutant Destruction Removal Devices
Some air cleaners use ultraviolet (UV) light technology intended to destroy pollutants in indoor air. These air cleaners are called ultraviolet germicidal irradiation (UVGI) cleaners and photocatalytic oxidation (PCO) cleaners. Typically, these systems are added on to particle removal systems rather than be used as a standalone approach.
Finally, no single rating system allows homeowners to compare the effectiveness of different types of air cleaning options. However, experts recommend homeowners look at the particle removal air filter efficiency. The efficiency rating indicates how the filter removes airborne particles from the air stream that passes through it. The minimum efficiency reporting value (MERV) measures the efficiency of air filters installed in the ductwork of HVAC systems. MERV ratings (ranging from a low of 1 to a high of 20) also allow comparison of air filters made by different companies.
Remember that even the best mechanical air filters will not be able to capture larger airborne particles, such as dust, pollen, dust mite and cockroach allergens and animal dander because these particles settle rather quickly to the floor and don’t ever make it to the filter. Although human activities such as walking and vacuuming stir up particles, most of the larger particles resettle before an air filter removes them.
Also, some residential HVAC systems lack sufficient fan or motor capacity that accommodates higher efficiency filters. Therefore, check the HVAC manufacturer’s information prior to upgrading filters to determine whether it is feasible to use a more efficient filter.