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indoor air pollutants: cigarette smoke, pollen, dust mites

Why do I need an air purifier?

According to the U.S. Environmental Protection Agency, the air indoors can be two to five times more polluted than the air outside. Since we spend most of our time indoors, consistently breathing poor indoor air can have a significant impact on our health. The number of ailments can include allergies, asthma, and respiratory issues. Having an air purifier can assist to remove impurities in the air we breathe. A good air purifier will filter out pollutant particles like pollen, dust, dust mites, mold spores, ragweed, and pet dander. Combined with an Activated Carbon/Charcoal filter and True HEPA filter, air purifiers are regarded as the most effective air purification products on the market.

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HEPA Air Purifiers

Developed in the 1940s, High Efficiency Particulate Air (HEPA) technology was made popular by use in medical cleanrooms, and it is still the most reliable and effective technology used. Air purifiers equipped with a HEPA air filter absorb up to 99.97% of all particles, like allergens, pollen, dust, dander, and others that are 0.03 microns and larger in size; harmful indoor air particles that cause allergy and asthma symptoms are measured to be about 0.03 microns or larger.

To put it simply, HEPA filters trap air contaminants in a complex web of fibers. Depending on the size of the particle, this can happen in four different ways: Inertial Impaction, Diffusion, Interception, or Sieving.

Larger contaminants are trapped via inertial impaction and sieving. The particles either collide with the fibers and become trapped or are trapped while attempting to travel through the fibers. Medium sized particles, as they move through the filter, are grabbed by the fibers via interception. Smaller particles are dissipated as they travel through the filter and eventually collide with a fiber and are trapped.

Not all HEPA air filters are washable. HEPA filters are made out of loosely and randomly interlaced fibers that are not built to stand up to any stress beyond that of a vacuum cleaner. Please refer to your use care guide to determine the proper maintenance instructions.

Bacteria, dust, and pollen and other microscopic particles are absorbed by HEPA air filters, so the air that re-circulates in your home is clean, fresh, and scarce of harmful contaminants.

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Electrostatic Air Purifiers

An electrostatic air purifier is very similar to HEPA air purifiers, except they do not use air filters. Electrostatic air purifiers use an electrical charge to trap particles traveling in the air stream. As a result, the charged particles stick to the sides of the internal filtration system on collection plates, but only about 30% of particles are removed from your indoor air. Electronic air purifiers are low maintenance and only require cleaning of the collection plates for optimal efficiency. Although they are readily available, consumers who research air purifier technologies before making a purchase are sure to avoid Ionic Breeze and electrostatic models.


Ozone Generators

Ozone generators are air purifiers that intentionally produce ozone. Not all are effective, and some are not even appropriate for home use; they can be harmful to your family and can cause health problems, including respiratory tract irritation and breathing difficulty. Historically, ozone generators have been used in commercial applications to purify the air and remove airborne particles, chemicals, mold, viruses, bacteria, and odors. However, ozone is not effective at cleaning the air except at extremely high, unsafe ozone levels.


Technologies That Complement HEPA Style Filtration

The best technology to pair with HEPA style filtration in air purifiers really depends on your concern. There are many different technologies that are used in air purifiers with HEPA style filtration, such as activated carbon, pre-filters, ultraviolet light, and ionizers. Choosing the best air purifier with the most efficient technology can be easy with some research and comparison. While searching through many air purifiers to find your perfect solution, be aware that the technology used is the most important factor you should consider.

  • Captures large particles
  • May be washable
  • Extends life of HEPA filter
  • Requires maintenance
  Activated Carbon
  • Absorbs odors, gases, and chemicals
  • Leaves space smelling fresh
  • Removes tobacco smoke and pet odors
  • Heavy
  • Expensive
  Ultraviolet Light
  • Neutralizes microorganisms, like bacteria and viruses




A pre-filter captures the largest particles before they reach the more expensive HEPA filter. Most of the particles in your air are large particles like dander and dust, not tiny ones like pollens and microbes. Even though HEPA filters have a large number of pleats to maximize their surface area, they can fill up quickly if larger particles are not pre-filtered out. 

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Activated Carbon

Elements like activated carbon, zeolite, or potassium permanganate are added to air purifier filters to increase efficiency to the filtering system. These elements work to absorb smoke, gases, chemicals, and odors that are present in the air.

Activated Carbon, also known as "activated charcoal" filters, are powerful products cleaning air from dust and dirt.  These filters are specially treated with oxygen in order to open up the pores of the carbon atoms so they can eliminate smaller particles and even odor.

Carbon neutralizes odors and traps harmful chemicals and gases in its pores to provide relief from activities like secondhand smoke, off-gassing from plastics, and harmful fumes produced from renovations. An effective filtering system that is also equipped with chemical adsorption materials can produce cleaner and fresher-smelling air.

Due to the nature of the job the activated carbon filters do, they cannot be washed or vacuumed, and they must and replaced regularly.


Ultraviolet Light

Ultraviolet light (UV) technology is key to neutralizing viruses and bacteria that accumulate on air purifier air filters. It is important to use the UV technology in combination with HEPA air filters and possibly activated carbon. Without a particulate filter system like a HEPA air filter, too many microorganisms may be hidden from the UV light, since it is not easily located on an air filter.

Do I Need Pre-Filters for My Air Purifier?

The Importance of Using Pre-Filters

Indoor air is full of particles, most of them large particles like dust. Skipping on a pre-filter may mean you wear out your main filter more quickly.

Indoor air is full of particles and in fact, most of the mass in the particles is in the larger particles, not the tiny pollens. The majority of the larger particles (dust, pet dander, etc) will be captured by an air purifier, and unless you use an air purifier technology called a pre-filter, the high-efficiency, more expensive HEPA filters will clog up with big particles too quickly. Even though HEPA filters have a large number of pleats which gives them lots of surface area, they can fill up more quickly if the larger particles are not pre-filtered out. In a typical family, with kids, dogs or cats, and a lifestyle that is highly active, an air purifier has to deal with a lot of large particles!

Pets are not the only ones with dander! Our first time air purifier owners are typically surprised at how much human hair and skin cells are caught in the pre-filter & main air purifier. Between humans and pets, especially cats, just the hair and fur can load up the pre-filter. That's one of the main reasons that the pre-filter on your air purifier should be changed, or at least checked according to a prescribed schedule. The aim is to keep the air purifier optimally pulling in the more toxic pollutants in the home or office. In both locations air purifiers with pre-filter technology can really help.

Does changing your pre-filter according to the prescribed schedule mean you'll never have to dust again? This is one of the most hopeful questions we get from our new air purifier customers. Unfortunately, an air purifier doesn't take the place of cleaning and dusting a home, but it definitely helps reduce the amount of dust in your home. While you vacuum and dust your home it is important to turn your air purifier on the highest speed, so kicked up particles that go airborne are captured in the air purifier and filtered out of your air.

An air purifier is key to running a healthy home, so you might as well use it most efficiently and effectively by changing the pre-filter as prescribed by the manufacturer. It is a very good idea to put the date that you should check the pre-filter either on your calendar or on a piece of paper taped to the air purifier.


Activated Carbon in Home and Room Air Purifiers

For many people, the first time they encounter activated carbon is during the process of selecting home air purifiers. Although most of our customers begin their search because of allergies or asthma, many soon learn how odors and chemicals can contribute to respiratory problems. To that end, many quality room air purifier systems offer a comprehensive solution that include activated carbon in order to these issues.

History and Use in Purification Processes
As many as 2000 years ago, human beings used activated carbon to remove impurities from water. Even then, its exceptional absorption qualities were known. However, it was not until the early 1900s that activated carbon was produced in powder form that could be sold commercially. At that time, it was used to purify water and to remove the color from sugar. As World War I progressed, it was discovered that activated carbon could be used in gas masks to protect soldiers, in addition to cleaning wartime water and in the manufacturing of air purifiers. It was during this period that granular activated carbon was developed.

Why Is It Called "Activated?"

What is the difference between carbon and “activated” carbon? The carbon used in air purifiers and water filters is actually put through a process of baking the carbon to dry it out. The heat used in the baking process drives out impurities, and causes the carbon to fracture at a microscopic level. This opens up a large surface area where impurities can be captured. After activated carbon has fully absorbed a large volume of impurities, it can actually be reactivated by heating it again. However, the reactivation process is impractical and dangerous. Non-activated carbon is soot or charcoal.

Activated carbon is described in a variety of ways, but generally the range includes amorphous carbon-based materials that exhibit a high degree of porosity and an extended surface area. This simply means that it has excellent absorbent characteristics that make it very useful for a wide variety of filtration processes, including air and water.


How Is Activated Carbon Used in Home Air Purifiers?

Carbon Can Be Used By Itself
In room air purifiers, the activated carbon is often combined with other minerals, like zeolite. Zeolite can absorb ions and molecules and thus act as a filter for odor control, toxin removal, and as a chemical sieve.

Carbon Can Be Treated to Target Specific Chemicals 
While activated carbon can adsorb hundreds of different chemicals and odors, it cannot remove everything. Carbon is not especially great at removing some common chemicals such as formaldehyde, or hydrogen sulfide. In these situations, the carbon may be impregnated with potassium iodide or blended with active alumina to increase absorption qualities. This means that all of the tiny spaces and crevasses within the carbon are holding an added chemical that now reacts with and neutralizes the airborne formaldehyde or hydrogen sulfide, rather than the carbon itself removing it.

As A Treatment for Multiple Chemical Sensitivity
A small segment of allergy sufferers have what is called Multiple Chemical Sensitivity (MCS). This means that they have a very high sensitivity to any airborne chemicals in the air. Perfumes, cleaning chemicals, and even off-gassing from household building materials can cause severe irritation to someone with MCS.

For these sufferers, an air purifier with a high volume of activated carbon can be used to remove irritants from the environment can make the air much more breathable for all, especially asthma sufferers, babies, children, and the elderly.


The Best Carbon/Charcoal Air Purifiers

The type and amount of activated carbon and how it is used in home air purifiers depends on the brand and model. In addition, there are over two dozen different high performance activated carbon air purifiers from half a dozen different brands. The type of carbon purifier that you want is going to depend on the type of chemicals and irritants you need to remove.


What is Clean Air Delivery Rate (CADR)?

CADR is an attempt to provide a uniform, objective standard by which potential buyers can easily evaluate the effectiveness of an air purifier.  The United States Environmental Protection Agency explains the number in the following way:

"The CADR is a measure of a portable air purifier’s delivery of contaminant-free air, expressed in cubic feet per minute. For example, if an air cleaner has a CADR of 250 for dust particles, it may reduce dust particle levels to the same concentration as would be achieved by adding 250 cubic feet of clean air each minute." - Environmental Protection Agency

CADR is established standard and independent rating by the Association of Home Appliance Manufacturers (AHAM). It measures the efficiency of an air purifier, considering room size and the volume of clean air produced per minute. The removal of dust, pollen and smoke, which are the three most common indoor air pollutants, is rated. The higher the CADR, the better the air purifier. CADR ratings are recognized by professional organizations and businesses, including the EPA, FTC, and most major manufacturers and retailers.

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