Do Air Purifiers Really Work?

Air purifiers clean allergens, mold, and other contaminants from your air. If you choose the right type of filter for your home, these machines are generally effective and, in some cases, can benefit overall health.

How do air purifiers work?

Air purifiers come in many forms. Some are built for the home and may purify a whole room, while personal air purifiers may be portable or wearable.

Home air purifiers generally work by drawing in contaminated air and passing it through a series of filters or other cleaning technologies that remove pollutant particles and airborne allergens and then release purified air back into space.

The specific methods used to clean the air can vary, but they often include some combination of the following:

• Physical filtration. This involves trapping particles, such as dust and pollen, on a filter material. The filter acts as a barrier, preventing the particles from being released back into the air.
• Adsorption. Adsorption uses a special filter made of a material (such as activated carbon filters) that attracts and holds onto particles and gases to trap pollutants like volatile organic compounds (VOCs) and odors. Activated carbon filters can convert carbon monoxide to less harmful carbon dioxide.
• Electrostatic attraction. Electrostatic air purifiers create a charge around particles using an electrically charged plate or other components. This process, called ionization, produces charged particles, called ions, which attach to airborne particles in air. These work for dust, pollen, and pet dander by trapping them in a filter.
• Photocatalytic oxidation. This process uses light to break down pollutants such as VOCs into harmless substances.

Are wearable air purifiers effective?

Wearable air purifiers, also known as personal air purifiers, are devices worn around the neck or attached to a backpack or purse.

The effectiveness of wearable air purifiers is a topic of ongoing scientific debate. For example, a 2020 study found that a wearable air purifier with a HEPA filter and activated carbon filter reduced exposure to nitrogen dioxide (NO2) and fine particulate matter (PM2.5). However, participants did not see an improvement in pulmonary health, so it's unclear if wearable air purifiers confer real health benefits even if they are effective in reducing airborne pollutants.

The effectiveness of wearable air purifiers can depend on several factors, including the design and quality of the device, the type of filter used, and the level of pollution in the air.

What do air purifiers filter out?

Air purifiers can filter out a wide range of contaminants, including:

• Particulate matter. These include dust particles, pollen, airborne animal allergens (such as pet dander), and mold spores that can cause allergies or trigger asthma symptoms.
• Volatile organic compounds (VOCs). These are gases emitted by products such as paints, household cleaners (particularly disinfectant cleaners), and furniture.
• Bacteria and viruses. Air purifiers can help to reduce the number of harmful microorganisms in the air that cause infections.
• Tobacco smoke. Air purifiers work for smoke particles by cutting down on the odor and the negative health consequences of second- and third-hand smoke.
• Chemical fumes. Air purifiers can remove fumes from household chemicals and other sources that can be harmful if inhaled.

Different types of air purifiers and filters

Choosing the correct filter for the kinds of air pollutants in your home is crucial. In general, there are four types of purifiers/filters:

• HEPA filters. High-efficiency particulate air (HEPA) filters are made of a dense mesh that captures tiny particles like dust, pollen, and pet dander. They force air through the filter, trapping particles in the mesh.
• Ion air filters (aka ionizers or ionic filters). Ion air purifiers generate negatively charged ions that attach to particles in the air, making them heavy and causing them to fall to the ground.
• UV filters. UV air purifiers work by using ultraviolet light to kill germs and bacteria that may be present in the air.
• Carbon and charcoal filters. Charcoal air purifiers and activated carbon purifiers both use carbon in their filters and work by adsorbing pollutants and impurities that can cause unpleasant odors and potentially harm health.

What are the health benefits of air purifiers?

While not all research shows that air purifiers lead to better health, those with high-efficiency particulate air (HEPA) filters do tend to reduce particulate matter in the air and have been found in some studies to decrease systemic inflammation and blood pressure, improve lung function, and have cardiovascular benefits.

Air purifier therapy can remove pollutants and allergens from the air and reduce allergies (including those from pet allergies), asthma, and other respiratory problems. Air purifiers can also reduce the number of harmful microorganisms in the air, such as bacteria and viruses, which can reduce the risk of infections, especially for people with weakened immune systems.

Air purifiers may also help with sleep since air pollution has been connected to sleep quality and sleep-disordered breathing, such as snoring and sleep apnea.

Reducing exposure to pollutants and allergens can also improve mental health since indoor air pollution can trigger symptoms of anxiety, depression, and other mental health conditions.

Are air purifiers worth it?

Air purifiers can have various health benefits, especially for allergy and asthma sufferers. However, it is important to note that the specific health benefits of air purifiers depend on several factors, including the type of air purifier used, the air pollution level, and individual health.

How to choose the right air purifier

To help you choose the right air purifier, consumers need to consider the following:

1. The size of the room. Look for a model that is designed for the size of your room.
2. Type of filter. Determine what type of pollutants you want to remove from the air before purchasing a unit.
3. Noise level. Some air purifiers can be loud, which can be disruptive in bedrooms or other quiet spaces.
4. Cost. Air purifiers can range in price from under $50 to over $1,000.
5. Clean air delivery rate. Clean air delivery rate (CADR) is a performance metric that compares the decay rate of contaminant concentrations with the device, both on and off.