How Do Air Purifiers Work?

Change Dirty air to Clean Air
Although they may seem like a new innovation, air purifiers have been around for more than 200 years. The purpose of air purifiers started out as protective masks for firefighters and have evolved over the years to now protect you and your family from airborne pollutants. Learn how air purifiers work below.

More than 50 million Americans suffer from allergies and asthma, causing an increase in the concern for safe, indoor air quality. Now more than ever, Americans are looking for ways to improve their indoor air quality, and Air purifiers lead the pack in advancements for cleaner air. Air purifiers are part of a comprehensive approach to the reduction of allergens. AchooAllergy.com represents the top air purifier and air cleaner manufacturers including Austin Air, Blueair, and Aeris Health.

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 out allergens and pollutants from the air that can and cannot be seen by the human eye. To remove these objects, air purifiers typically use filters, electrical attraction, or ozone.

Air purifier filters utilize fine sieves that filter particles out of the circulating air. As air flows into the air purifier, the finer the sieve inside of the air purifier, the smaller the particles it will trap. High Efficiency Particulate Air (HEPA) filters are the benchmark for air purifier filters, which are guaranteed to trap 99.97% of airborne particles larger than 0.3 microns in size. Microns are the standard unit that is used to measure the size of particles in the air. Each micron is equivalent to 1/25,400 of an inch. The naked eye cannot see anything that is smaller than 10 microns in size, so pollutants like bacteria and viruses escape detection. HEPA filters efficiently remove smaller-sized allergens like dust, smoke, chemicals, asbestos, pollen, and pet dander. Room air conditioner filters can only capture particles 10.0 microns or larger, so they are not as efficient as air purifier filters for cleaning the air.

The more that air passes through a HEPA filter, the cleaner the air will become. 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 air purifiers will provide approximately 6 air exchanges per hour in an average room and they contain an average of 15 lbs of activated carbon/zeolite blends, which absorb chemicals and odors.

In addition to the HEPA filter, brands like Germ Guardian air purifiers offer an optional medical-grade ultra-violet (UV) light system that will quickly kill viruses, bacteria, and fungi when they enter the air purifier. UV light also protects the HEPA filter from biological and viral contamination.

Electrical attraction is another type of technology that air purifiers utilize to trap particles. There are three types of air purifiers that work by using electrical attraction: electrostatic precipitating cleaners, electret filters, and negative ion generators. A negative ion generator can sometimes be the sole cleaning element in the air purifier, or it can work alongside a HEPA filter.

Electrostatic precipitating cleaners or electronic air purifiers draw particles in by a fan and charge the particles 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. One thing to consider with electrostatic precipitating cleaners is that they usually are not as effective as HEPA air purifiers—they remove 95% of contaminants while HEPA air purifiers remove 99.97% of particles. In addition, another downside to these units is that many create a nasty byproduct, ozone.

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

Some brands like the Blueair air purifiers combine HEPA technology with their own electrostatic media filter technology. The airborne particulates that enter into the air purifier receive an electrical charge that helps them adhere more easily to the filter once it reaches it. 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 and stick to furnishings and other surfaces in your home, causing stains on them.

Ionic air purifiers will only remove certain types of particles from the air—they are not 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 that utilize HEPA filtration.

Instead of using filters to trap particles, ozone generators use high-voltage electrical currents that 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 to 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 your 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, which is why AchooAllergy.com does not carry them.

Asbestos and radon are growing problems in homes today. It is advisable to schedule radon testing immediately to take precautionary measures and avoid health risk such as lung cancer. Heating devices produce carbon monoxide and other dangerous gases, and chemicals like formaldehyde and ammonia are increasing in your 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 environmentally-friendly solution for air purification has become much easier over the years. The right air purifier will provide asthma and allergy sufferers with air that is free of harmful airborne pollutants. Most importantly, an air purifier will help to establish healthy, clean air quality in your home that is safe for you and your family to breathe.

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