How Do Air Purifiers Work?

Although they may seem like a new innovation, air purifiers have been around for more than 200 years. Beginning as protective masks for fireman, air purifiers have now evolved the ability to protect you and your family from airborne pollutants.

As allergies and asthma now affect more than 50 million Americans, the concern for safe indoor air quality has rapidly increased. Now more than ever, Americans are looking for ways to improve their indoor air quality. Air purifiers lead the pack in advancements for cleaner air.

Allergens like smoke, mold spores, pollen, bacteria, viruses, pet dander, and other pollutants damage your lungs and immune system. Unfortunately, most of these irritants cannot be seen by the naked eye. Air purifiers filter allergens and pollutants seen or unseen by the human eye. To remove these objects, air purifiers typically use filters, electrical attraction, or ozone.

Air filters utilize fine sieves that filter particles from circulating air. As air flows into the air purifier, the finer the sieve used, the smaller the particles it traps. The accepted benchmark for air filters has been set by the High Efficiency Particulate Air (HEPA) filters, which are guaranteed to trap 99.97% of airborne particles larger than 0.3 microns. Microns are the standard unit used for measuring air particles. Each micron is equivalent to 1/25,400 of an inch. The naked eye cannot see anything this small, so pollutants like bacteria and viruses escape detection. Room air conditioner filters only capture particles 10 microns or larger. HEPA filters remove smaller allergens like dust, smoke, chemicals, asbestos, pollen, and pet dander.

The more times the air passes through the HEPA filter, the cleaner the air becomes. The room capacity of a HEPA air purifier will determine whether the air cleaner can handle your air purifying needs. Top-of-the-line brands like Austin Air purifiers will provide approximately 15 air exchanges per hour in an average room and contain an average of 15 lbs of activated carbon/zeolite blends, which adsorb chemicals and odors.

In addition to the HEPA filter, brands like AllerAir and IQAir offer an optional medical grade ultra-violet (UV) light system, used to quickly kill viruses, bacteria, and fungi upon entry into the air purifier. UV light also protects the HEPA filter from biological and viral contamination.

Electrical attraction is another technology utilized by air purifiers to trap particles. Three types of air cleaners work using electrical attraction: electrostatic precipitating cleaners, electret filters, and negative ion generators.

Electrostatic precipitating cleaners, or electronic air purifiers, draw particles in by fan and charge them with a series of high-voltage wires. Several plates (precipitating cells) carry the opposite electrical charge and attract the contaminants as they pass by the plates. Electronic air purifiers are perfect for individuals who don?t want to worry about the costly replacements of HEPA filters. Friedrich electrostatic air purifiers remove approximately 95% of all airborne particles and carry low energy costs for you.

Electret filters in air purifiers use synthetic fibers that create static charges to attract particles. Electret filters are offered in a variety of types including plain, pleated, disposable or reusable. Depending on the type of filter you need, will determine how often the filter requires replacement.

Some brands like Blueair combine the HEPA technology with their own electrostatic media filter technology, which charges the incoming particles instead of the filter. By marrying the two unique purification systems together, Blueair created a more effective air cleaner.

Negative ion generators or ionic air purifiers use tiny, charged wires or needles to create gas molecules with negative charges or ions that adhere to the airborne particles and collect in the filter. However, many ions end up back in the air, sticking to furnishings and other surfaces that may be stained by them.

Ionic air purifiers only remove certain types of particles and aren?t always effective against gases, chemicals, or odors. Some ionic air purifiers have been shown to re-circulate the same dirty particles that they draw in, making them much less effective than traditional air purifiers using HEPA filtration.

Instead of using filters to trap particles, ozone generators use high voltage electrical currents to convert oxygen to ozone, which acts as a powerful oxidant and breaks down molecules and microorganisms in the air. Several tests have proved that ozone generators are not very effective at removing indoor allergens.

Ozone, in fact, can be hazardous to your health, and both ozone generators and ionic air cleaners emit ozone. In nature, lightning creates ozone when it cuts through oxygen molecules in the air. In the atmosphere, ozone helps protect us from harmful UV rays; however, on the ground level, ozone is a powerful lung irritant. When created artificially, ozone can actually aggravate allergies and asthma, damaging the lining of nasal passages and lungs, causing coughing, throat irritation, chest pain, and shortness of breath. The Environmental Protection Agency and the American Lung Association advise against using ozone generators.

Asbestos and radon are growing problems in homes today. Heating devices produce carbon monoxide and other dangerous gases, and chemicals like formaldehyde and ammonia are increasing in the home environment. Since most Americans stay indoors an average of 90% of the time, providing fresher and cleaner air has never been more important.

Finding an environment-friendly solution has become much easier. Learn about air purification today. The right air purifier will provide asthma and allergy sufferers with air free of airborne pollutants and establish healthy indoor air quality for you and your family.

Scott Smith is an expert on indoor air quality and air purifiers at achooallergy.com.