What Does an Air Purifier Do? How They Work and Why You Should Get One

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Written By Jamila W.

While the air inside your home should be clean and safe, air pollutants such as pet dander, mold, dust particles, and allergens can find their way in an lower the air quality inside your home.

Air purifiers are small, portable devices destined to filter the air in a single room. The are great for making the air in your home easier (and healthier) to breathe by reducing air pollution, airing out your home, and some can even be used to reduce or increase humidity. 

The trick is knowing enough about how air purifiers work to buy the right one for your home

Table of Contents

air purifier in a room

What Is an Air Purifier?

An air purifier is a small device designed to improve air quality by removing pollutants and contaminants from the air.

They are usually used to reduce the presence of tiny particles (called allergens) like dust mites, pollen, pet dander and mold. They can also be used to reduce smoke particles and eliminate odors.

How Do Air Purifiers Work

An effective air purifier uses a fan to pull in air from its room and runs that air through an internal filter to clean it of unwanted particles. The clean air is then circulated back into the room. This filtration process happens several times an hour to improve indoor air quality.

Many air purifiers feature HEPA filters that capture particles like dust, pollen and mold spores, while other use features like UV lamps to kill airborne viruses and bacteria. One thing to keep in mind is that an air purifier is typically rated to clean the air of a certain size room.

Do I Need an Air Purifier?

The short answer is probably, especially if you have children. The Environmental Protection Agency has published research revealing that indoor air quality is often drastically lacking, often having up to five time the airborne particles as outdoor air.

What Types of Air Purifiers Exist

The most common way to categorize air purifiers is based on either its size, or the way that it cleans the air. The most common air cleaning types are:

  • HEPA (High-Efficiency Particulate Air) Filters: HEPA air purifiers use physical filters to capture small particles like dust, pollen and pet hair. HEPA filters are usually designed to remove 99.7% of particles as small as 0.3 microns.
  • Absorbent Purifiers: Activated Carbon is used to absorb odors, gasses and chemical pollutants. These filters use a large surface area to to attract and neutralize as many organic compounds as possible.
  • UV-C Light: These air cleaning devices suck in air and use UV light to kill viruses, bacteria, and fungi for cleaner air. UV light air purifiers are sometimes combined with portable HEPA air cleaners, with the UV light killing virus that would otherwise land on the HEPA filter.
  • Ozone Generators: This portable air cleaner uses high-voltage electrical currents to convert oxygen to ozone, which breaks down molecules and microorganisms in the air. Several studies have shown that ozone generators are not very effective at airborne pollutants. Studies have also shown that ozone-generating air purifiers may pose a health risk.
  • Electric attraction: There are actually three types of residential air purifiers that work with electric static attraction: 1) electrostatic precipitating cleaners, electric filters, and negative ion generators. Ionizers form an electric field so that ionic particles become positively or negatively charged. The ions attached to bacteria and other air particles, and are pulled towards the oppositive charge of the air purifier.

Are Air Purifiers Effective?

Air purifiers can be very effective in improving air quality but it is very important that you pick the most effective air purifiers for your situation. For example, if your primary concern is odor or chemical removal, it is probably best to stick to activated carbon filters which are effective at absorbing and reducing odors, smoke and chemical pollutants.

On the other hand, if what you are concerned about is larger particles like pet hair, it is best to stick to an air purifier with a HEPA Filter. You also need to keep in mind the room size the filter will be used in and make sure you replace filters often enough.

If the indoor pollutants you are concerned about include mold, then a UV unit is out, especially if you have moisture problems in your walls or basement.

What Household Contaminants Should I Worry About?

itchy eyes

Research from the American Lung Association, tells us that harmful particles can lead to allergies and cause difficulty breathing and itchy eyes, nose and throat. Allergens like smoke, mold, pollen, bacteria, and other pollutants attack your lungs and immune system.

Most of these irritants cannot be seen with the naked eye, making it easy unknowingly breathe in all the pollutants that make you sicker.

Do Air Purifiers Improve Your Health

They can contribute greatly to improving both your health and comfort, especially if you are prone to the kinds of lung and respiratory conditions that air pollutants can aggravate. In addition to avoiding illness by removing harmful particulate matter, air purifiers help with asthma management and allergen reduction.

Can portable air purifiers make a difference?

Portable air purifiers can be especially helpful because they allow for targeted air cleaning. While your home HVAC system likely has a filter, an air purifier draws in air from a particular room, meaning that you can use it to help out in high traffic or particularly problematic areas of your home.

You will need to make sure you choose a portable air purifier with the right features and specifications for your family and your living space.

Air Purifier Benefits

There are a few key benefits of using an air purifier:

  • Reduce Indoor Air Pollution by filtering out airborne particles
  • Relieves asthma symptoms by capturing pet dander, pollen an dust mites
  • Eliminates harmful chemicals from indoor environments, reducing health risks
  • Neutralize unpleasant odors from volatile organic compounds (VOCs)
  • Reduces the changes of airborne diseases by capturing bacteria and viruses
  • Improves sleep quality by filtering out allergens and reducing disruptions
  • If using activated carbon filters, can remove hazardous radon gas, helping to protect against lung cancer
  • Captures asbestos particles, helping to reduce the risk of lung disease

What Should I look for in an Air Purifier

When picking the best air purifier for your home, you should keep a few things in mind:

  1. Room Size: Larger rooms generally need bigger unit and mean you will spend more money on air filters. A small unit will often not up be up to delivering clean air in a large room or home.
  2. Energy Costs: Nowadays, many units are designed to be energy efficient but if you will be running it consistently, this can become a concern.
  3. Maintenance Requirements: As a unit works to trap particles you will need to change your air purifiers filter. In fact, if you have pets and a lot of traffic in your home, you will often go through one or more filters every few months.
  4. Certifications: Many home appliance manufacturers get their products rated by the Asthma and Allergy Foundation of America. If you or your children suffer from asthma, be sure to get a unit with the “Asthma & Allergy Friendly” Mark
  5. Clean Air Delivery Rate (CADR) : An air purifier’s CADR tells you how quickly you can use an air purifier to to filter dust, smoke and pollen particles from a particular room size. CADR is measured in cubic feet per minute (CFM) and a high CFM indicates that the filters can work quickly to give you better air quality. If you have an average size room, you want to target a CADR of about 400.
  6. Ozone Emission: Because ozone gas can be harmful to your respiratory system, you want to make sure that the filter you buy does not generate ozone during the filtration process.

What They Won’t Work For

This largely depends on what kind of air cleaner you are using. For example, ionizers are not very effective when used on gases or odors, instead activated carbon should be used if dealing with those issues.

Likewise, the you will run through multiple filters when using a HEPA filter and will also need to make sure that the exhaust fan is kept clean.

Other Ways to Clean Indoor Air

air purifier

There are steps you can take in addition to using an air purifier to improve indoor air quality. A few that should be done:

  1. Regularly brush your pets. This will reduce the amount of dander and hair that is released in the air as they shed.
  2. Clean and Vacuum Regularly. This reduces the strain on your air filter by reducing the amount of dust and dirt that is around to get kicked up in the air. It is crucial to do this at least once a week if you or your children suffer from allergies.
  3. Use a dehumidifiers to prevent mold and mildew growth.
  4. Open windows periodically to let in fresh outdoor air.
  5. Grow air cleaning plants. In addition to acting as natural air purifiers, they can also dilute the carbon monoxide levels in a room.

The Bottom Line

The best way to keep the air in your home clean is to use both an air filter and an air purifier. While air purifiers are great for neutralizing toxins and particles in the air, once they settle on the ground they won’t be able to filter them out. Use an air filter (usually in your HVAC system) to keep harmful particles out of the air and keep your home clean by vacuuming and mopping.

Questions and Answers

Can Air Purifiers help protect against Covid-19?

While Air Purifiers alone are not enough to protect against COVID-19, the Environmental Protection Agency recommends the use a true hepa filter in addition social distancing and mask wearing to reduce airborne transmission of Covid-19 indoors.

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