In recent times, there have been growing concerns about pollution levels. But when most people think about air pollution, they usually assume that the conversation is about outdoor air pollution. According to the Environmental Protection Agency, indoor air can be up to five times as polluted as outdoors1. This is mainly because the air indoors does not get as circulated as outdoor air, allowing pollutants to thrive. This has led many to wonder what is air purifier and whether or not it can help them maintain the air quality in their home. 

Manufacturers often promise that air purifiers can help refresh indoor air and reduce the risk of health complications caused by polluted indoor air. In this article, we answer the questions of whether or not air purifiers work and how to choose the best one should you decide to buy an air purifier.

What is air purifier? Benefits, Types, How to The Best & FAQ’s

Do Air Purifiers Work?

Yes, a good quality air purifier offers the promise of filtering out pollutants in the air such as dust, smoke, and pollen. Most of them do an excellent job at this. Given the right condition, air purifiers can indeed make the air in your interior space healthier, especially when it comes to getting rid of particulate contaminants.

However, not all of them are great for removing gaseous pollutants such as radon or VOCs from the air. Also, since air purifiers rely on air circulation to work, they will only remove allergens displaced in the air. Particles embedded into flooring and furniture are not captured effectively by air purifiers.

Also, while purifiers do work, don’t expect them to replicate the 99% effectiveness that many products claim. Many of these results were derived from laboratory tests and not from real-world situations where many external factors such as the size of your space, rate of airflow, and installation location can influence the effectiveness of your air purifier.

In summary, air purifiers work effectively to get rid of particulate pollutants in the air. But most of them are limited for filtering gases, and the level of effectiveness you get depends on a wide range of factors.

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Benefits Of Air Purifier

Air purifiers (especially those with HEPA technology) promise to eliminate up to 99.7% of particles in the indoor space. Getting rid of these pollutants offers several health benefits both in the short and long term. Some of the benefits of using an effective air filter include:

  • Relieves Symptoms of Asthma and other respiratory issues: People living with asthma and several other respiratory issues are vulnerable to pollutants like pollen, dust mites, and pet dander which can irritate their airways, making it difficult for them to breathe and causing other complications. While cleaning your home regularly and maintaining proper ventilation will help reduce these pollutants, many of them may remain suspended in the air you breathe in. Household air purifiers with HEPA filters can capture these pollutants, ensuring that the air you breathe is clean and fresh.
  • Eliminates Harmful Chemicals in the Air: Exposure to chemicals like carbon monoxide, nitrogen dioxide, ammonia, and chlorine can have various effects on your brain and general body health. Many of these toxins somehow find their way into your home. While exposure to these chemicals in small quantities may not harm you, continuous exposure may put you at risk of neurological disorders, cardiovascular issues, cancers, or tumors. Air purifiers (especially those with activated carbon) can help trap these chemical contaminants and prevent the health problems they cause.
  • Neutralizes Unpleasant Odors: Off-gassing due to the breakdown of gasoline, formaldehyde, benzene, and similar chemicals can give your indoor space a terrible odor. This can cause breathlessness, nausea, and other adverse effects. HEPA air purifiers and models with carbon filters do a good job trapping these gasses and reducing their concentration in the indoor air.
  • Reduces the Chances of Airborne Diseases: Everywhere around you, pathogens are floating in the air. They cause a wide range of health complications, including cold and flu. If a member of your family gets sick, more of these pathogens are released into the air, causing others to get sick as well. HEPA air purifiers can trap disease-causing micro-organisms like viruses and bacteria, safeguarding everyone in your home from them. This is particularly important if a member of your family has a weakened immune system that makes them vulnerable to such infections.

Types Of Air Purifiers

Air purifiers typically come with different types of filters such as HEPA filters (High-Efficiency Particulate Air filters), carbon filters, UV light filters. These filters determine how the air purifier unit will function and what it can do. The following are the different types of air purifiers based on the type of filter they contain.

  • HEPA model: Air purifiers with High-Efficiency Particulate filters can capture pollutants that are as little as 0.3 microns in size. This makes them quite effective for trapping different types of airborne particulate matter as well as some micro-organisms.
  • Activated Carbon model: Activated carbon filters are designed to trap gaseous matter. While they can’t capture micro-organisms as HEPA air purifiers can, they can help get rid of bad odor.
  • Negative Ion Model: These types of air purifiers have electrostatic precipitators that charge up air particles that pass through the filter. This makes them practical for trapping pathogens and other particulate matter. However, electrostatic precipitators need to be changed often, or they could constitute a health risk.
  • Ultraviolet Light Model: Most air purifiers don’t do a go job at trapping germs in the air. But purifiers with UV filters are built for this purpose. The UV rays can kill germs in the air to make your indoor air healthier.
  • Ozone Model: Ozone air purifiers are designed specifically for absorbing foul odors. However, they are not very recommended since exposure to ozone can cause a wide range of health complications, even at low levels.

How To Choose The Best Air Purifier?

If you have decided to purchase an air purifier, there are certain factors to put into considerations. This ensures that you enjoy the benefits of using a purifier and helps avoid some of the negative issues associated with a wrong purchase. Here’s how to choose the best air purifier for you.

  • Consider the size

Air purifiers have different capacities. This means they are designed to purify the air in rooms of various sizes. You must compare the size of your room to the capacity of the air purifier you intend to purchase since air purifiers operate the most efficiently if they’re appropriately sized.

  • Noise Level

The noise level of your air purifier varies from one unit to the other. The range is between 35 to 75 decibels for most units. If you are sensitive to loud noise when you sleep, you should go for a low-noise purifier to avoid disruptions to your sleep.

  • HEPA Filters

The most effective air purifiers have HEPA filters capable of trapping small-sized particles and pathogens. But beware. Many manufacturers advertise their air purifiers as HEPA-type or HEPA-like. These are not true HEPA filters and are not very efficient for getting rid of pathogens.

  • Asthma and Allergy Friendly Certification

Asthma and Allergy Foundation of America has a certification program that rates air purifiers on their claims of allergen control. Products with an Asthma and Allergy Friendly Certification have been made to undergo various tests to confirm that they indeed remove harmful allergens from the air as they claim. Look for this certification, especially if you have someone living with asthma or suffering from allergies in your home.

  • Clean-Air Delivery Rate (CADR)

This specifies how fast the air purifier can eliminate dust, smoke, and pollen particles in a given room size. It is measured in Cubic Feet per Minute (CFM) and should be specified for any buying product. Ensure that the CADR rating for your air purifier is suitable for your room size.

  • Air Change Per Hour (ACH) Rating

This is another important factor that determines how efficiently your air purifier unit operates. It indicates the number of times the air purifiers circulate the air in your room within an hour. The higher the ACH rating, the more efficient the air purifier is. Thus, a unit with a high ACH rating (at least 4 or 5 times) is more recommended.

  • Ozone Emission

Be careful about air purifiers that emit ozone as they filter the air. Even in small quantities, ozone gas can cause various respiratory issues.

  • Ease of Cleaning And Maintenance

When you’re buying an air purifier, you should consider the ease and cost of maintenance. The main consideration as far as air filter maintenance is concerned is the cost of air filter replacement. Some units may include washable filters. But in most cases, they aren’t very energy efficient. HEPA filters are more energy-efficient, but you have to change the filters more often (at least once in three months). A unit with multiple filter types does a better job at purifying the air, but it also means you have to buy more than one filter as well.


  • What does an air purifier do?

The primary purpose of an air purifier is to remove pollutants and allergens from the air. This varies from particulate contaminants like dust and dirt to gaseous ones as well as biological pathogens. How effectively an air purifier does this job depends on the type of unit you buy. Results may also vary from one indoor environment to the other.

  • Where should I place my air purifier?

Typically, it would be best if you placed your air purifier close to a window or doorway. This is because air purifiers work better with sufficient airflow to lift dust, molds, and other particles that the air purifier eliminates. It is also recommended that you place your air purifier at least 3 to 5 feet above the ground. This allows it to capture both vertical and horizontal air movement and operate more effectively.

  • Should I sleep with the air purifier on?

Yes, it is okay to sleep with an air purifier on. According to the Asthma and Allergy Foundation, an air purifier promotes better breathing during sleep and improves sleep quality. Thus, leaving an air purifier on in your room can make the environment more comfortable and safer. However, like every other appliance, you should take precautions if you’re leaving your air purifier on overnight. Make sure the area in front and behind the unit is clutter-free. This ensures efficiency and also prevents a fire hazard.

  • How often should I clean my air purifier?

Generally, manufacturers recommend cleaning your air purifier and changing the filters every 3 to 6 months. However, the specific answer to this depends on the type of air purifier, how often you use it, and the indoor air condition in your home. For instance, if you leave your air purifier daily, it has to be cleaned more frequently than the one you only use occasionally.

  • How to tell if an air purifier is working?

The major way to determine if your air purifier is working properly is by checking the airflow. They have fans that are meant to draw air from the room and return it after filtering. If the purifier powers on, but the fan doesn’t seem to be blowing any air, then it most likely isn’t working. The fan of your purifier should make some sound. If it isn’t making any sound at all, then the unit isn’t pulling any air. Similarly, if the fan is running too loud, there might be a problem with the filter.

You can also examine the air filter in the purifier after running it for some time. If the unit has been working effectively-capturing pollutants before expelling air from the device, then the filters should be whole and dirty. Of course, you should remove the filter and replace it before it gets clogged. But a dirty filter is a good sign that the unit is working correctly.

Finally, you can install an air quality monitor. This is a device that tracks changes in air quality in your home. Measure the air quality before turning on your air purifier, then do a test again after running the monitor for a while to see the difference.

  • Does an air purifier help with Covid?

A good quality air purifier (with HEPA filters) can reduce airborne contaminants in space, including viruses like the Coronavirus. However, it is essential to note that filtering your air alone is not enough to protect you from Covid. Even though installing an air purifier helps, it should be combined with other practices recommended by the CDC. This includes wearing a mask, maintaining proper hygiene, and following social distancing regulations.


Using an air purifier has several benefits. It is significant for those who suffer from frequent allergic reactions, asthma, and other respiratory issues. But even if you don’t experience any of these, maintaining a clean and healthy space can still improve your quality of life and help you sleep better. This is why you should know what an air purifier is and how to choose the right one for you to ensure you get the best results from buying one for your home.

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