Can air purifiers make you sick?

This article discusses whether air purifying devices have any adverse effects on human health. We discuss the conditions in which air purifiers can be doing more harm than good. Lastly, we discuss the methods and the alternatives in order to prevent the negative implications of air purifiers on human health.

Can air purifiers make you sick?

No, air purifiers cannot make you sick. Air purifiers are devices that are designed in the manner to keep the indoor air clean, therefore minimising the chances of an individual to fall ill.

However, there are certain conditions in which air purifiers can be doing more harm to one’s health than good. Therefore, it is important that one knows the various ways or the types of air purifiers that can be causing this to happen.

Why do we need an air purifier?

Air purifiers, as the name suggests, are devices that are responsible for cleaning the indoor air, by getting rid of the pollutants present in it.

There are many types of air purifiers available in the market, and some of these are:

  • High efficiency particulate air (HEPA) filters
  • Air ionisers
  • Ozone generators

These air purifiers can have additional components, such as a UV light chamber, activated carbon filter, and so on, which are mainly designed for widening the spectrum of the device’s efficacy against various pollutants.

Many people wonder whether an air purifier is the right investment. However, in the current scenario, where air pollution is prevalent and worsening with each passing day, especially in urban areas, air purifiers are very vital.

Air pollution is the presence of undesired substances in the form of solids, liquids, or gases, which are suspended in the ambient air, and can adversely affect human health.

These pollutants can be especially harmful if present in the indoor environment. The average human being spends more than 90% of their total lives in an indoor environment, with more than 80% of it inside a building.

Indoor air, just like outdoor air, is susceptible to pollution. Indoor air can get polluted when pollution from outdoors infiltrates through openings such as doors, windows, cracks, seeps, etc.

Indoor air can also get polluted from indoor sources, which can arise from things such as furniture, household items, solvents and dyes, spores from mold and mildew, combustion of fuels and firewood, and hobbies/activities such as smoking, etc.

The pollutants generated from these sources have been shown to adversely affect human health, and continuous exposure to elevated concentrations can cause many serious issues, such as cancers, respiratory and cardiovascular disorders, and even death.

This is where air purifiers come in. They help to get rid of the pollutants in the indoor air, thereby keeping it clean and fit to breathe.

How air purifiers can be harmful

Air purifiers can sometimes contribute in certain manner due to which one may be vulnerable to diseases. Some of these are:

  • Breeding ground for mold and bacteria
  • Generation of ozone gas
  • Cannot filter out VOCs and viruses
  • Can generate more house dust
  • Low efficiency of air ionisers

We shall discuss these in more detail.

Breeding ground for mold and bacteria

For cases where the HEPA air purifier is installed in rooms with high relative humidity, one of the common substances to get trapped in the air filter would be mold and bacteria.

High levels of relative humidity, as well as the space  available within the air purifying device provides the optimal dark and humid condition within the filter itself that promotes the growth of mold and bacteria.

Not only will this reduce the efficiency of the filter, it will also serve as a breeding ground for mold and bacteria, which in turn would be propagated through the air purifier.

Although mold is usually harmless and causes minor issues pertaining to the respiratory system, there are certain species (e.g.: Black mold) which on inhalation can cause serious harm if it is not diagnosed and treated in the early stages.

Generation of ozone gas

Certain air purifiers use ionisers that generate ions at the rate of thousands per minute, or electric plates that cause the electrostatic deposition of charged pollutants.

Furthermore, there are also ozone generating air purifiers which claim to help in cleaning the air in an indoor environment.

However, in their process, they can cause a breakdown of oxygen molecules, which in turn react with each other to form ozone.

Ozone is a highly reactive gaseous molecule which is naturally present in the upper layers of the atmosphere, where it absorbs the sun’s damaging ultraviolet radiation.

When present in the lower levels of the atmosphere, however, it acts as a pollutant, and can have serious adverse effects on human health, which also includes afflictions related to the cardiovascular and respiratory systems.

Ozone’s instability helps it to get rid of odors by modifying the chemical makeup of particles or other gases in the air, making the air appear fresher and cleaner.

Ozone generators, on the other hand, do not truly filter out the tiny particles that cause asthma. Ozone acts as an irritant, due to its pungent odor. 

It can cause wheezing, irritation in the nose and throat, runny nose, watery eyes, difficulty in breathing, and so on. 

Additionally, ozone can also worsen the condition of people who are suffering from diseases such as asthma, emphysema, and bronchitis.

Cannot filter out VOCs and viruses

VOCs is an acronym for volatile organic compounds, which refer to a variety of organic compounds that are emitted from certain materials in the form of a gas. 

These compounds are present in commonly stored household products, such as paints, solvents, cleaning products, cosmetics, and fuels.

All of these products release VOCs when in use, as well as when they are stored. Exposure to VOCs can cause short term health effects such as irritation of the eyes, nose and throat, headaches, and nausea.

Long term exposures can adversely affect the liver, kidneys, and the central nervous system. 

In the current scenario, the covid pandemic has been a prevalent issue. Studies have shown how the virus can spread indoors from infected articles to healthy people. Hence, prevention is necessary.

However, this is where HEPA air purifiers fall short. They fail to get rid of VOCs, and cannot catch virus particles, since the typical size of a virus is less than the effective range for the air purifier’s functioning.

Can generate more house dust

Unlike the air purifiers with HEPA filters, air ionisers do not help with dust present in the house. On the contrary, they would contribute even more to the dust generated indoors.

Air ionisers interact with the charged pollutant particles by sticking to them, causing them to become too heavy to stay suspended in the ambient air.

This would in turn cause deposition of dust on surfaces such as carpets, tables, etc., which in turn would exacerbate the effect of dust already present indoors.

However, it would be ideal to pair it with an air purifier containing a HEPA filter, as it would increase the efficiency with which the indoor air gets cleaned.

Low efficiency

Conventional air purifiers are known for their high efficiency rate of removing pollutants from the ambient air. However, the same cannot be said for air ionisers.

In an experiment carried out by Shi et al, air purifier necklaces that use anions as their purifying mechanism were used from different brands in a small stainless steel chamber. 

It was found that the particles had a highly variable particle removal rate, but did not perform efficiently. Some of the devices had discharged at a relatively shorter amount of time.

How can one prevent this?

There are numerous ways to prevent air purifiers from harming your health. These methods include:

  • Avoid investing in an air ioniser and ozone generators
  • Using activated carbon filters
  • Regular maintenance and replacement of HEPA filters

Avoid investing in an air ioniser and ozone generators

Air ionisers as well as ozone generators give rise to ozone, a highly reactive gas. Although ozone gas helps to get rid of smells and odor by reacting with them, it can also cause respiratory issues such as bronchitis, asthma, shortness of breath, and so on.

This is because of the high reactive nature as well as the characteristic pungent odor ozone has. Therefore, it is wise to refrain from investing in such types of air purifiers.

Using activated carbon filter

Activated carbon filters are very effective when it comes to getting rid of odors and gaseous pollutants in the indoor air. The activated carbon absorbs the gaseous molecules that are responsible for this into its own matrix, therefore keeping your air odor-free as well as free from gaseous pollution.

Regular maintenance and replacement of HEPA filters

HEPA filters need to be maintained as well as replaced on the basis of their usage. This is to be done in order to ensure that your air purifier is working perfectly as well as preventing any side effects that could arise from an ill-maintained air purifier.

Other FAQs about Air Purifiers and Filters that you may be interested in.

Can I change my air filter myself?

Are K&N filters better than OEM?

Are air purifiers good for sinus problems?


Air purifiers, when not maintained properly, can end up adversely affecting the health of the users. Some air purifiers, such as ionisers and ozone generators, have side effects that far outweigh their benefits.

Therefore, one must refrain from investing in such types of air purifiers, buy air purifiers that have an activated carbon filter, and ensure that their device is regularly maintained and the filters are replaced on a regular basis.


Is there radiation from air purifiers?

Yes, air purifiers produce a safe & small amount of electromagnetic field (EMF) radiation. However, there is no data supporting the claims that they’re harmful. Therefore, one should not worry about side effects due to radiation.

How to tell if my air purifier is producing ozone?

Although manufacturers usually mention it along with the product, sometimes, due to technical issues, your air purifier might start generating ozone. 

You can tell whether there is ozone by looking out for some of the  most common symptoms such as a feeling of irritation in the eyes, nose and throat. 

Some people may also experience respiratory or heart symptoms such as shortness of breath, chest pain, and wheezing.

How often should I replace my air filters?

The frequency of replacing your air filters depends upon the indoor air quality of your house. If you live with a small number of people, have pets, and are near a polluted area, you might need to replace your filters as early as 1-2 months.

However, if you live alone with no pets or other animals, you can replace your filter once every 6-12 months.


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