The Air Purifier Big Book Of Information

Purchasing an air purifier is an important part of a healthy lifestyle. But, with so many options on the market, choosing the right one can be daunting. 

 We’re here to help! Our complete guide will help you understand the technology behind different purifiers, which purifier is best for your home, and how to keep your purifier running at peak performance.

But, before going into the details of air purifiers, let’s first talk about why exactly you need one.

Why Should You Buy an Air Purifier?

The World Health Organization estimates that over 90% of people around the world live in areas with unhealthy levels of pollutants. This dirty air can affect your life in so many different ways.

Here are just a few of the many benefits of owning an air purifier:

Longer life expectancy: Studies have shown pollution to be “the largest environmental risk factor worldwide,” responsible for many more deaths than alcohol use, physical inactivity, or high sodium intake. Air pollution actually reduces global life expectancy by more than a year.

Improved lung and heart health: Both lung and heart disease have been tied to air pollution. 

Better sleep: Pollutants can interfere with your sleep, which, in turn, affects your overall health.

Better mental health: Multiple studies have shown that mental health disorders increase in areas with poor air quality. 

Improved memory and cognition: Indoor pollutants have been linked to a decrease in memory and cognition. 

Decreased allergy and asthma symptoms: Both allergy and asthma symptoms are aggravated by pollutants in the air. 

Odors and harmful gases removed: Unpleasant odors and toxic gases can decrease your quality of life. The right air purifier will get rid of both. 

What Should You Consider When Choosing an Air Purifier?

Now that you know why you need an air purifier, how do you decide which air purifier to get? The first step is to determine what your specific needs and priorities are.

Room size

Different sized rooms require different air purifiers. CADR is useful in determining which sized purifier to get.  CADR indicates how much air is filtered in an hour for three particular pollutants (smoke, pollen, and dust) in Cubic Feet Per Minute (CFM). The higher the CADR number, the faster the air purifier filters the air.

Generally, the CADR of your air purifier should be equal to at least two-thirds of the room’s area. There are online calculators available to help determine the minimum CADR you’d need for each particular room.

Types of filters

While there are several options, HEPA filters are typically considered the safest and most effective purifiers for home use. In fact, the CDC even recommends using HEPA filters in hospitals and other buildings to help keep indoor air pollutant-free. 

A TRUE HEPA filter must be able to trap 99.95 percent of particles that are 0.3 microns. That .3 micron size is important because scientists have determined that particles of that size evade air filters more than larger or smaller particles. 

But a HEPA filter alone will not get rid of all the pollutants in your home. An activated carbon filter is necessary to remove odors and harmful gases.

Noise level

Considering that a HEPA air purifier is essentially a large fan that pulls air through a filter, there will generally be some type of noise. Especially if the purifier is designed to clean a large area.

Unfortunately, the air purifier industry does not have standards for sound emissions. In fact, manufacturers are not obligated to reveal any specifics on noise levels. But, most reputable purifier companies do give some information on noise level, as measured in dB(A).

For perspective, rustling leaves rate at a dB(A) of 0 and a lawnmower rates at about 80 dB(A).

A very quiet air purifier would rate at around 10 dB(A) and a more typical one would be 20 dB(A).

The ACH rating

ACH rating stands for “Air Changes per Hour”. The ACH number shows the relationship between the volume of air and how much air the purifier moves per minute (CFM). 

The ACH rating provides a quick way to compare purifiers. It’s typically best to look for air purifiers with at least a 4x ACH rating.


CFM stands for cubic feet per minute.  It’s the amount of air that passes through the purifier at a certain point. The higher the CFM count, the larger the space the air purifier can clean. A basic rule of thumb is that you need about 100 CFM for each 250 square feet of space. A standard room air purifier typically has around 400 CFM.

What type of purifier is best for your indoor space? 

While all air purifiers claim to remove pollutants from your indoor air, they are not all the same. In fact, some purifiers can actually make your indoor air less healthy.

Here are the most common types of air purifiers currently available:


Ionizers use high voltages to give an electrical charge to molecules in the air. These charged molecules are called ions. The ions are attracted to particles or surfaces with the opposite charge, causing them to clump together into larger heavier particles that fall out of the air or get stuck to charged surfaces like coaches or curtains. The problem is that although your air may feel fresh when using an ionizer, the pollutants are actually just stuck to surfaces around the room where they can then be recirculated into the air.

Ozone Purifiers

Ozone purifiers take in oxygen (O2) from the air and give it a strong electrical charge. This electrical charge allows the oxygen molecules to rearrange themselves and form O3, also known as ozone.

The ozone is then released into the air where it collides with pollutants like mold and smoke and changes their chemical composition. The problem is that the extra oxygen molecule can also interact with substances inside your body, causing chest pain, coughing, shortness of breath, and throat irritation.

UV purifiers

UV purifiers use short wave ultraviolet light (UV-C) to destroy airborne pollutants by breaking down their DNA or RNA, so that they’re unable to perform vital functions or reproduce. Unfortunately, it takes air less than a second to filter through purifiers, which isn’t enough time to destroy most contaminants. 

Photocatalytic Oxidation (PCO)

Photocatalytic oxidation purification is a process in which pollutants undergo a chemical reaction that transforms them into non-toxic substances. 

There are major drawbacks to PCO, the most concerning of which is the fact that the pollutants produced by photocatalytic air purifiers may pose a greater risk to human health than the ones they are designed to remove.

Activated charcoal filters

Activated charcoal filters use extremely hot charcoal to trap pollutants. When the temperature of the charcoal is raised, the elements and compounds that were bound with the carbon atoms are removed and all the binding sites for carbon become “free” for binding, which means that odors and volatile organic compounds get removed from circulation. 

HEPA Filters

A HEPA filter is made of interlaced fiberglass or plastic fibers that are twisted into a maze designed to remove particles from the air circulating in your home. 

The particles are trapped in different ways according to their size.

Particles larger than 1 micron are heavy enough that the airflow pushes them into the fibers of the filter where they get stuck.

Particles that are .3  to 1 micron can fit in between the gaps in the filter. But, because they are too heavy and slow to follow the airflow around the HEPA filter, they get stuck in the fibers. 

Particles that are smaller than .3 microns are small and light enough that they bounce off larger particles in the air in random patterns, causing them to get caught in the HEPA fibers.

Getting the Most Out of Your Air Purifier

If used properly, an air purifier can save you money in the long run. There are a few factors to consider to ensure that your purifier is working at its highest capacity. 

Choose an ideal spot for your purifier

Air purifier effectiveness is largely dependent on where the purifier is placed. The more air that’s available to the purifier, the faster the purifier can clean it.  Placing your purifier near windows or doorways will allow for the most air to enter your purifier and be cleaned.

It’s generally a good rule to make sure that the air purifier has at least a foot of space on the front, back, and sides of it so it will clean the air in the entire room. This means avoiding placing the purifier in corners and keeping the room as obstacle-free as possible.  

Placing an air purifier 3-5 feet off the ground will be even more effective since it allows you to be able to capture both the horizontal and vertical air movement.

Replace filters regularly 

HEPA filters typically need to be changed every 6-12 months.

Some devices come with built-in smart systems to let you know when it’s time to change your filters and how well your purifier is performing. 

Leave purifier running

While you may be tempted to turn off the purifier when you’re away or sleeping, the truth is that, in order to be most effective, an air purifier should remain on all the time. That’s because the air in your home is continuously changing. Not only does outdoor pollution seep in, but indoor pollutants are released every time you do things like turn on the stove, open packages, fold clothes, or use scented products… not to mention the dander and hair that is constantly generated if you have pets.

Even the best air purifiers can take hours to clean all of the air inside of a room. Every time you turn off the purifier, pollutants begin to accumulate again, making it more difficult for the purifier to do its job.  Leaving the air purifier on continuously will allow new contaminants to be removed as they are introduced.

For more in depth information about the different types of air purifiers on the market check out our blog.

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