Air purifiers: how long does it take to feel the effects?

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The effects of running an air purifier can be felt after 15 minutes. All the air in the room will have gone through its filters and over 90% of airborne particles will have been captured. For the quickest results, you will need an air purifier with the right clean air delivery rate (CADR) and air changes per hour (ACH).

This article discusses how quickly you can feel the difference in air quality when running an air purifier. It also mentions which air pollutants are captured by an air purifier and which symptoms are commonly related to these pollutants. Additionally, I go over which air purifier specifications are needed for the quickest results.

You might not feel any difference

Cleaning the air with an air purifier does not necessarily mean you will feel any difference. It is perfectly possible to clean the air of many pollutants and not notice any difference. This happens because not everyone is as equally susceptible to the effects of air pollutants. Also, some air pollutants only cause long-term health effects but aren’t noticeable otherwise.

Not everyone has the same symptoms, if at all, for every air pollutant. For example, I am relatively sensitive to dry air, getting dry eyes where others don’t feel any difference. Others might be allergic to pet dander, or have asthma and feel instant relief when the air is cleaned of dust.

You will need to have air quality-related health symptoms to notice any difference when running an air purifier. There are many different symptoms that can be related to certain air quality issues. However, these symptoms don’t necessarily have to come from air pollutants, and if they are, these symptoms might take time to recede even when the air is clean.

If you want to know more about air pollutants and their effects on your health. I recommend reading my article:

How quickly does an air purifier clean the air?

With every bit of air cleaned by an air purifier, the overall concentration of pollutants in the room lowers. Therefore, the air becomes cleaner over time. At some point, one or more pollutants that cause you to have symptoms will drop below the level when you feel their presence.

However, modern air purifiers have great filters that capture almost all particles from the air in one go. Therefore, it is safe to say that your air will be cleaned of particles once all the air has run through the device once.

The following factors determine how quickly the air becomes clean:

  • The concentration (amount) of a certain pollutant
  • The size of the room
  • The speed of the air purifier (called air changes per hour/ACH)
  • The quality and condition of the filters

Let’s assume once all of your room’s air has passed through the filters the air is clean enough to relieve any symptoms. In that case, we need to look at the air changes per hour (ACH) of your air purifier. This tells you how many times per hour all the air in your room has gone through the machine.

For example, when the ACH is 1, it runs the air in your room through its filters once per hour. If the ACH is 4 it does so 4 times per hour. Once every 15 minutes.

This of course only works when the machine is the right size for your room. Air purifiers come with an indication of the size of the room they are fit for.

Additionally, air purifiers give an indication of their CADR, the clean air delivery rate. There are mormally three CADRs given for the three pollutants they capture from the air. The CADR gives an indication of how quickly these pollutants are cleaned by the purifier. Check out my article for more information about the CADR. You can find it here:

What difference can you feel?

There are many symptoms that can be related to poor air quality. According to the Environmental Protection Agency (EPA), these symptoms include:

  • irritation of
    • eyes,
    • nose or
    • throat
  • headaches,
  • dizziness,
  • fatigue,
  • increased symptoms of
    • asthma, or
    • other pre-existing illnesses
Air purifier dust filter ful of dust
A dust filter can easily fill up in a week

Other symptoms can take years to develop, so you won’t be able to feel any difference once you use an air purifier. These symptoms include:

  • respiratory disease
  • heart disease
  • cancer

      Naturally, you can only feel a relief of symptoms that come from pollutants the air purifier actually captures. Therefore, you might want to read more about what an air purifier can and cannot remove. I recommend reading my article about this here:

      If you are unsure if your air purifier is actually doing something, I recommend reading my article: