Can air purifiers make you sick? We Explore the Claims

An air purifier is made to ensure that the air that is inhaled is clean and safe to breathe. There is a rumor that posits that air purifiers can indeed make a person sick. Is there any validity to these claims? There is, but only in the most narrow and specific of conditions.
In the following, we analyze the most pertinent situations that could cause these air purifier problems and how to mitigate them:

Can air purifiers make you sick? Causes, Risks & Prevention Tips

Below are the causes why air purifier make you sick.

1. Some Air Purifiers Produce Ozone

Ozone is a gas that happens to be a major component of smog. Some air purifiers, unfortunately, produce ozone. Ozone is dangerous when inhaled, though it is a natural gas found in the environment. According to health guidelines, ozone concentrations above 70 parts per billion (ppb) can pose significant health risks when experienced over an extended period. This highlights the importance of choosing air purifiers wisely to avoid hazardous health effects.
Inhaling large concentrations of ozone gas can provoke irritation in the airways and lungs, which in turn can lead to:
Coughing and headaches
Inability to breathe and a constricted chest
Asthma attacks or the onset of asthma
Oxygen-deprived lungs, especially in the elderly, children, or those who have a history of health issues.
Not every air purifier releases ozone, though certain manufacturers like to cloak them in terms, “activated oxygen, “energized oxygen,” or even “super oxygenated.” If you see those terms, it is best to avoid them, as it is simply repackaged and put out as a product that yields ozone.
Tip: Do not buy air purifiers that produce ozone.

2. Washable Filters Could Be Problematic

Purifiers usually work with two types of filters:
Removable filters: Simple to replace when full – no hassle, no mess, no risk of spillage.
Washable filters: They require scut work whereby one is exposed to the dust, allergens, and germs that the purifier has been keeping. In addition, they are almost impossible to achieve complete cleanliness which makes the purifier lose its functionality.
Tip : Use only replaceable filters. They are safer, neater, and more practical in the long run.
Related Article: Does an Air Purifier Help with Carbon Monoxide?

3. Undersized Purifiers

If the purifier is too small for the room, it won’t remove pollutants effectively. A good rule of thumb is to ensure the Clean Air Delivery Rate (CADR) is at least two-thirds of the room’s square footage. This can help you quickly determine if a purifier is suitable for your space.
E.g., A device rated for 50 sq. ft. used in a 100 sq. ft. room leaves half the air unfiltered.
Tip: Use correct size filters.

4. Wrong Placement

More commonly, filters can accumulate dirt, bacteria, and allergens, especially when regular disturbance is not made to the filters.
Mold, in particular, can propagate and be blasted back into the room if the accumulated dirt is not cleaned and the filters are not replaced.
Cleaning and replacing filters must be done regularly to prevent falling ill.
Units trapped in corners, behind furniture, or suffocated under piles of clothing suffer the most.
Little is known, however, about placing a purifier too close to the bed. This may lead to morning headaches and dry air discomfort due to direct nozzle airflow.

5. Effects of Purified Air

Dry Air: Some devices omit humidity, which can lead to sore throats, nostrils, or even sinus irritation. Using a humidifier can help.
VOC off-gassing: Some filters or plastics might emit chemical fumes or even a scent. Leaving the units out for a couple of hours might help.

How Side Effects from Improper Use May Appear

Sore throat.
Coughing.
Chest tightness or heaviness.
Headaches or dizziness.
Symptoms of asthma or allergies are exacerbated.
Nose or sinus irritation.

Related Article: Can an air purifier help with dust?

What To Consider To Ensure Your Air Purifier Remains Safe and Productive.

In addition to avoiding ozone and washable filters, the most important features of a purifier include:
Multi-layer filtration: The most dependable systems have several stages of filtration. Even the lesser systems have five stages, which include:
Medical-grade HEPA 13 filter: Captures ultra-fine particles that the naked eye cannot see, offering high-level filtration for allergens and dust.
Activated carbon filter: Adsorbs odors, gases, and volatile organic compounds (VOCs), ensuring the air smells fresh and is free of chemical pollutants.
UV-C light: neutralizes bacteria and viruses. Also, moisture and even spores of mold.
With such devices, they generate remote filters which make use of a combination such as a pre-filter, a medical-grade HEPA 13 filter, a UV-C light, and an activated carbon filter.
These will take out not only pet dander and dust, but even smoke, mold, and harmful gases.
These filters have a life span of three months. Some devices that issue timely alerts when such changes are live will ease your work. Such air filters are safe, ultra-quiet, and even adaptable to the air quality of your home.
Related Article: Can an air purifier help with mold?

The Risk of Ozone Air Purifiers to Your Health

Let’s get to the basics. What is ozone and why is it considered one of the components of some “air purifiers”.
Some home air purifiers create ozone (Ozone O₃) by giving an electric charge to oxygen(O₂), and some do it while using ionizing and electrostatic devices and consider it an ‘accidental byproduct’ of their working processes. Other companies go all out and call it “activated” or “energized” oxygen and try to sell it as if it is some new innovation. Well, here is the news: ozone is not oxygen; it is still a strong gas that irritates the lungs.

How ozone impacts the body

The same reactivity that allows ozone to oxidize microbes or odors is the same that will react with the organic tissues of your airways. Even a little of it can do the following:
Set off throat irritants, coughing, tightness in the chest, and breathlessness.
Asthma as well as the ability to defend yourself against respiratory infections, will be much worse.
The lungs, and especially the olfactory cells, will suffer long-term damage and will be exposed to repeated exposure. This is considered the most heinous in the sense that with chronic exposure, the symptoms can go away; however, the damage continues.
Some individuals with a specific chronic condition will have a stronger impact. children, older individuals, and those suffering from asthma or chronic lung disease.

Ozone plus indoor chemistry means new irritants

Ozone doesn’t work alone in the indoor environment. It interacts with indoor airborne chemicals, especially with terpenes, which include the scents of citrus cleaners, pine disinfectants, and scented candles, and produces irritants like formaldehyde and other aldehydes and possible carcinogens. So, instead of “neutralizing” pollution, it creates more pollution.
Ozone works at relatively low concentrations (ranging from low parts per million to low percent) with materials such as rubber, plastics, and fabrics, which is proof of its corrosive power.

Air cleaning by means of ozone generators

These devices are often marketed by vendors as “ozone-free” and as purifying because they “break down” contaminants into “benign” CO₂ and water. But the truth is:
For the vast majority of indoor chemicals, ozone reactions are very slow (on the order of months to years), meaning that, at the concentrations necessary to keep safe, no cleaning takes place.
Particles, which include dust, pollen, and dander, that account for the majority of allergy-related issues, are not removed.
At the levels that are considered safe, more of the ‘ozone-free’ devices fail to disinfect bacteria, fungi, and viruses, and mold that is often found in stagnant conditions in most rooms. Levels required for disinfecting are not considered safe for the people in the environment.

Can an air purifier help with mold?

Two more added burdens. Ionizers and electro-static units

Absolutely no other devices add as many problems to this issue. It must be ozone-free as the tests with the most sensitive and stringent devices show that all electronic air cleaners (ozone-free as they are dubbed), must contain air with high levels of charge.
Particles in space do not get taken out. Charged particles, the “black wall effect,” stick to walls, furniture, and ceilings, then return to the air. Surfaces remain dirty, and exposure continues.
Even UV add-on lights do not help much in freely moving air; exposure times are too short, and bulbs decrease a significant percentage of output over time.
There is limited control over your exposure.
Indoors, the level of ozone varies with device output, room size, position of the doors, ventilation, and your distance from the unit. “Following the instructions” is irrelevant because users are often exposed to levels of ozone that now exceed public health limits. Relying on your sense of smell is not a valid strategy. Odor adaptation sets in quickly, making these instructions useless.
What about empty rooms?
High levels of ozone are used in empty rooms (for instance, during fire-damage restoration), but that is not air cleaning. There are unknown and potentially harmful byproducts, possible material damage, and exposure control that is critical to the safety of humans and pets.

Can an air purifier help with dust?

Safer, proven Prevention Tips

To better the air we breathe indoors, prioritize the following hierarchy:

Eliminate: Begin by reducing or eliminating emission sources like smoke, strong solvents, and high-terpene cleaners. Ensure moisture problems and damp areas are cleaned and fixed.
Ventilate: Enhance airflow by removing pollutants from the kitchen, bath, and other areas, while allowing fresh, ambient air into the building when external conditions are suitable.
Filter: Utilize mechanical filtration with ozone-free purifiers that are appropriately sized for the room. Opt for True HEPA filters for particles and activated carbon for gases and odors, ensuring pollutants are removed physically rather than through chemical reactions.

Related Article: Do air purifiers help with a Stuffy Nose

What to do to Stay Safe

Choose purifiers with filters only, ozone-free, True HEPA + activated carbon.
Do not operate the unit if filters are dirty; instead, replace them on schedule.
Set the unit in open areas that are not air circulation dead zones (do not place it in corners).
The CADR rating should not be greater than the room size.
Use the humidifier if the air is dry.
The unit should be left unused, and the manufacturer should be contacted if the user starts to feel worse.
In essence, air purifiers are safe when chosen, sized, and maintained properly. Most problems arise from models that emit ozone, issued models, and wrongly used models.

Can air purifiers make you sick? Final Takeaway

Yes, air purifiers can make you sick. As long as you don’t use air purifiers that emit ozone or force you to deal with dirty washable filters, you’re in good shape. And both of these risks are easy to manage.
Consider an ozone-free purifier with replaceable filters and multiple layers of protection. You will enjoy cleaner, safer air, free of unwanted negatives.

Can air purifiers make you sick? FAQS

Why is my air purifier making my allergies worse?

An air purifier can sometimes worsen allergy symptoms depending on the type of device and how it’s used. The most common reasons include ozone production, poor maintenance, and using the wrong size or type of filter.
Possible reasons your air purifier may aggravate allergies

Ozone production: Some purifiers generate ozone, either intentionally (ozone generators) or as a byproduct of ionizers. Ozone is a known lung irritant that can make asthma and allergy symptoms worse
Ionizers: These devices charge particles so they fall out of the air, but they often release ozone and don’t fully remove allergens.
Dirty filters: A saturated filter full of dust, pollen, or mold can re-release these particles into your room.
Blocked airflow: If intake or output vents are obstructed, allergens may build up on the device instead of being removed.
Wrong filter type/size: A filter not matched to your room’s square footage won’t effectively trap allergens—or could be too strong for household use.

How to prevent your purifier from making allergies worse

Choose True HEPA filters: Certified HEPA filters are the most effective for trapping allergens. Avoid ozone-producing features: Skip units with ozone generators, ionizers, or “activated oxygen” marketing. To ensure regular maintenance, consider setting a phone reminder on the day of purchase to replace filters every 90 days. This approach helps turn maintenance into an automatic habit, supporting long-term health gains.
Maintain regularly: Replace or clean filters according to the manufacturer’s schedule.
Place correctly: Keep the unit in an open space with good airflow, not behind furniture or next to curtains.
Look for certification: Devices approved by groups like the Asthma & Allergy Friendly Certification Program ensure safety and performance.
Use with other strategies: Combine filtration with allergen-control practices such as washing bedding in hot water, using mattress covers, and managing humidity.

How do I know if my air purifier produces ozone?

Ways to check:

Smell test: Ozone has a sharp, chlorine-like odor similar to bleach or electrical sparks.
Read the manual/specifications: Responsible manufacturers disclose ozone output in product documentation.
Check certifications:
- CARB (California Air Resources Board): Look for CARB-certified models or search their approved list online.
- Energy Star: Some Energy Star models provide ozone emission details.
Know the technology:
- Ozone-free: Units with only mechanical filtration (HEPA, carbon) don’t create ozone.
- Possible ozone producers: Ionizers, UV-C lamps, and photocatalytic oxidation (PCO) systems can generate ozone.

If you suspect your purifier makes ozone:

Turn off any ionizer or UV features.
Check the manual or the manufacturer’s website for guidance.
Contact the company if unsure
For peace of mind, consider using a home ozone meter.

What does ozone smell like?

Ozone has a distinctive odor that many people can recognize.
Common descriptions:

Chlorine/bleach-like: Sharp and pungent.
Metallic: Reminiscent of burning wires or sparks.
Electrical: Similar to the smell after lightning or from a faulty electrical device.
“Clean” or “fresh”: Some describe it as crisp, like air after a thunderstorm.

Where you might notice it:

Outdoors after a lightning storm.
Near photocopiers, printers, or sparking electronics.
Around ozone generators or purifiers with ionizers/UV features.

Important: Even if the smell seems “fresh,” high ozone levels are unsafe. Strong ozone odor indoors is a sign you should ventilate immediately and reduce exposure.
Related Article: Do air purifiers help with asthma?

What are the symptoms of being exposed to ozone?

Breathing ozone can irritate and damage your respiratory system, even at low levels.
Common short-term symptoms:

Coughing, sore throat, or throat irritation
Chest pain or tightness
Wheezing or shortness of breath
Headaches
Eye, nose, or sinus irritation

More severe effects:

Worsening asthma attacks
Reduced lung function (harder to take deep breaths)
Lung tissue damage (similar to a sunburn on the inside of the lungs)
Greater vulnerability to respiratory infections

Who is most at risk:

Children and infants
Elderly people
Asthma or allergy sufferers
Smokers

If you suspect ozone exposure, ventilate the area and avoid further exposure, especially if you notice breathing problems or worsening allergy symptoms.
Related Article: Can I Leave the Air Purifier On 24/7

References:

https://www.thehealthsite.com
https://www.reddit.com
https://ww2.arb.ca.gov
https://medicalnewsbulletin.com