Do air purifiers work? Research, best practices, and more



March 12, 2024


Air purifiers improve indoor air quality by eliminating pollutants like dust, pollen, pet dander, and smoke. They're particularly beneficial for allergy or asthma sufferers. When buying, consider filter type, room size, noise level, and energy efficiency.


How do air purifiers work?

Air purifiers are devices designed to improve indoor air quality by removing various contaminants from the air. They function by drawing in air using a fan and passing it through one or more filters that trap particles and pollutants before releasing purified air back into the room. These filters can be made of different materials, such as paper, fiberglass, or mesh. The effectiveness of an air purifier depends on the quality of the device, the type of filter used, and the volume of air it can handle.

The most efficient filter for particles is the High Efficiency Particulate Air (HEPA) filter, which can capture at least 99.5% of particles in the air that are 3 microns or smaller. In addition to HEPA filters, some air purifiers use electrical attraction to trap particles, like electrostatic precipitating cleaners, electret filters, and negative ion generators. Adsorbent filters can help mitigate odors, while UV purifiers use ultraviolet light to eliminate bacteria and mold on HVAC indoor cooling coils. However, their effectiveness can vary based on the specific model and design of the air purifier.

What do air purifiers filter?

Air purifiers can effectively filter out a wide range of airborne pollutants and contaminants from the air, including:

  • Dust and dust mites
  • Pollen and other allergens
  • Pet dander and hair
  • Mold and mildew spores
  • Smoke particles from cigarettes, wildfires, and other sources
  • Bacteria and viruses
  • *Volatile organic compounds (VOCs) from cleaning products, paints, and other household items

The choice of filter and air purifier model can influence their effectiveness in removing these particles from the air.

Can air purifiers filter the outdoor air that enters your home?

It's important to note that outdoor air quality largely depends on factors beyond your control. However air purifiers can be helpful in reducing the amount of indoor air pollutants present in your air no matter if they come from indoors or outdoors.

To improve indoor air quality further, you may consider additional measures like sealing gaps and cracks in your home, using weather stripping, and installing screens on doors and windows. These steps can help minimize the entry of outdoor contaminants into portable air.

Are air purifiers worth the money?

Whether an air purifier is worth the investment depends on your specific needs and circumstances. They can be valuable in the following situations:

  • Health issues: If you or someone in your household suffers from allergies, asthma, or respiratory problems, an air purifier can help alleviate symptoms by reducing indoor air pollutants.
  • Location: Living in an area with high air pollution or experiencing frequent wildfires can make air purifiers more worthwhile, as they can help mitigate the effects of outdoor pollutants.
  • Comprehensive approach: Air purifiers work best as part of a broader strategy for maintaining healthy indoor air. This includes reducing sources of pollutants, ensuring adequate ventilation, and making improvements to your heating and cooling systems.
  • Costs: Consider the initial purchase price, operational costs, and filter replacement expenses. Energy-efficient models with Energy Star certification can help reduce ongoing costs.

Room with clean air

What is a HEPA filter?

HEPA filters, short for High Efficiency Particulate Air filters, are a type of filter widely used in air purifiers. They are exceptionally effective at capturing ultra-fine particles in the air, such as dust, pet dander, pollen, mold spores, and other common allergens in homes. A true HEPA filter can trap at least 99.5% of particles that are 3 microns or smaller in size.

Airthings Renew - HEPA-13 filter

What does the research say?

Portable HEPA air purifiers have been shown to benefit individuals with allergies and asthma, as well as support cardiovascular health. However, the research also suggests that air purifiers may not be particularly useful for certain pollutants, such as mold, nicotine, gaseous contaminants, animal dander, cockroach allergens, some VOCs, and larger, heavier allergens like dust mites. It's essential to understand the limitations of air purifiers and consider them as part of a broader approach to maintaining clean indoor air.


What should I look for in an air purifier?

When choosing an air purifier, consider the following factors:

  • Filter type: Look for models with HEPA filters for effective particle removal.
  • Room size: Select an air purifier with an appropriate capacity for the size of the room.
  • Noise level: Consider the noise generated by the device, especially if it will be placed in a bedroom or living area.
  • Energy efficiency: Opt for energy-efficient models, indicated by certifications like Energy Star.
  • Maintenance: Evaluate the ease of filter replacement and the associated costs.
  • Additional features: Some air purifiers offer features like timers, air quality sensors, and remote controls, which can enhance convenience.

How Airthings indoor air quality monitors can help ensure the effectiveness of your air purifier at home

Air quality monitors provide real-time data on various air quality parameters, enabling you to make informed decisions about the operation of your air purifier. Here's how Airthings can assist in this process:

Continuous monitoring: Airthings monitors continuously track key air quality metrics, including levels of particulate matter (PM2.5 and PM10), volatile organic compounds (VOCs), temperature, humidity, and radon. This constant monitoring ensures that you have up-to-the-minute information about the quality of the air in your home.

Baseline measurement: Before you start using an air purifier, it's essential to establish a baseline measurement of your indoor air quality. Airthings monitors allow you to understand the initial state of your air, identifying any existing issues with allergens, pollutants, or other contaminants. This baseline measurement serves as a reference point for assessing the purifier's impact.

Air purifier effectiveness: Once you've introduced an air purifier, you can monitor its impact on your indoor air quality using the Airthings monitor. Track changes in PM2.5 and PM10 levels, as these represent fine particles that the purifier should be capable of removing. Reduced VOC levels can indicate the air purifier's effectiveness in dealing with gases and odors.

Data-driven decisions: Airthings monitors provide data in an easily understandable format, typically through a mobile app or web interface. You can observe trends to improve air quality and make decisions based on the data collected, such as adjusting the air purifier's settings or filter replacement schedules.

Optimal placement: Proper placement of your air purifier is crucial for its efficiency. Airthings monitors can help you identify specific areas of your home where air quality is a concern, guiding you on the best placement for the purifier.

Airthings App - Purifier


Is it good to use an air purifier everyday?

Yes! It is advisable to turn off the air purifier during the night, even during the night. Many people think switching on the lights at night or at night to avoid energy consumption is logical and efficient and is recommended to run it at optimum efficiency.

Do doctors recommend air purifiers?

Although a purifier may be effective at removing air contaminants from the house, it is not strictly recommended by doctors or any medical body. However, allergy and asthma patients may find air purifiers that have a HEPA filter useful to remove airborne particles.

Do air purifiers really help with dust?

Air purifier filters remove pollutants, allergens and other contaminants from the air. The effectiveness of these products for the removal of the dust is based on certain devices' specific capabilities.

How long should you run an air purifier in a bedroom?

Most air purifiers filter the entire indoor atmosphere in 30 minutes to 2 hours; although more contaminants could come in at anytime. If your home contains pollen and allergens, it should always be conditioned with a purified air source and kept clean.

Does sleeping with an air purifier help?

A purifier helps increase circulation of oxygen thereby making breathing easy or reducing snoring. Air purification helps reduce the risk of snoring and helps everyone have more peaceful nights.




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