Are Air Ionizers Harmful?

Air ionizers are devices that are sold as air cleaners or purifiers, and are typically aimed at people with allergies or asthma. While the effectiveness of these devices varies depending upon the design and brand, most air ionizers are not harmful. However, some emit dangerous molecules that can aggravate the problems that they are supposed to relieve.

Air Ionizers

Ozone is found naturally in the upper atmosphere.

Air ionizers work by electrically producing ions. These ions stick to particles and are either collected by plates within the ionizer or stick to the walls and floor nearby. The plates or the surfaces around an air ionizer must be cleaned regularly, or the particles drift back into the air. Air ionizers are relatively safe. However, some produce significant amounts of ozone, which is a harmful molecule.


Ozone is a molecule formed from three oxygen atoms. It is unstable and highly reactive. Ozone forms naturally in small amounts in the upper atmosphere of the earth, and also forms during lightning storms. It forms around many kinds of electrical equipment in small amounts. It is sometimes used to purify air and water, because it is a powerful germicide; however, it is typically mixed with oxygen because pure ozone is so highly reactive that it can be dangerous. Air ionizers sometimes produce a sweet smell that might be mistaken for the smell of clean air, a sign that the ionizer is working. This is actually the smell of ozone being produced by the ionizer.

Health Hazards

Ozone poses a significant risk to health. When inhaled, ozone damages lung tissues, worsening asthma and allergy symptoms. Exposure to ozone is associated with problems with lung function and increased mortality rates. Inhaling ozone causes a number of symptoms, including irritation of the the eyes, nose and sinuses. It can also cause asthma-like symptoms such as shortness of breath, coughing and wheezing.

Air Ionizer Dangers

Air ionizers are generally not harmful. However, it is important to know how much ozone an air ionizer produces. Lower levels of ozone are better; some ionizers produce 150 parts per billion of ozone. One hundred parts per billion is enough to cause lung damage in people with no lung or breathing problems. It is also important to not put air ionizers in areas that a person might sit or sleep for long periods of time, as this can cause a person to breathe toxic levels of ozone.