Do Air Ionizers Work For Allergies? How effective are they?

Do air ionizers work for allergies?

Another really common question many people have about air ionizers, is do air ionizers work for allergies? Allergies of all kinds have been on the rise recently. Consequently, more and more people are looking for alternative solutions instead of regular meds. Many companies claim that their air ionizers do wonders for allergies, while quite a few users report conflicting experiences. With so many different opinions and claims, it can be quite hard for someone new to the air purifying world to figure out which information is correct and which is misleading. Here is everything you need to know about allergies and air ionizers.

Air borne allergies caused by Air Purifiers

  1. Ozone Production: Some air ionizers produce ozone as a byproduct of the ionization process. Ozone is a known respiratory irritant and can cause breathing difficulties for people with asthma or other respiratory conditions.
  2. Electrostatic Attraction: Air ionizers work by emitting negatively charged ions into the air, which can attract positively charged particles, including allergens such as dust, pollen, and pet dander. However, this process can also cause these particles to become airborne, which can lead to increased exposure and symptoms for people with allergies.
  3. Incomplete Filtration: While some air ionizers include a filtration system to remove particles from the air, these filters may not be able to capture all allergens. As a result, some particles may still be present in the air and become more easily dispersed due to the ionization process.
  4. Increased Airflow: Air ionizers often use fans to circulate air throughout a room. While this can help to distribute ionized air, it can also lead to increased circulation of allergens in the air.
  5. Maintenance Issues: Air ionizers may require regular cleaning and maintenance to ensure they are functioning properly. If not properly maintained, these devices can become a source of allergens themselves, as dust and other particles can accumulate on the ionizer plates or filters and be released back into the air.

It’s worth noting that not all air ionizers will necessarily generate airborne allergens, and some models may be designed specifically to minimize these effects. However, it’s important to carefully research and evaluate any air purifier or ionizer before purchasing to ensure it is safe and effective for your specific needs.

So, do air ionizers work for allergies? Yes, air ionizers can greatly reduce, and in some cases even completely relieve all allergy symptoms. However, the results greatly depends on two factors: the amount of negative ions that an air ionizer produces, and if there is any ozone byproduct. If negative ion emission is high enough, and if the air ionizer does not produce any ozone – then you have the perfect combination to combat allergies. Negative ions have both an indirect + direct role in preventing and relieving allergies. This is due to their cleaning capabilities and certain healing attributes of negative ions.

That was the short answer to the question. In the next few paragraphs, I will provide a more detailed explanation.

Air cleaning abilities of negative ions

To understand why negative ions work for allergies, we need to first take a look at the cleaning abilities of negative ions. As you probably already know, air ionizers clean the air with negative ions. Simply said, negative ions are negatively charged particles that attach themselves to positive particles. Simple math. Allergens, among other air pollutants, are positively charged particles. They float in the air around us until we come into contact with them and inhale them into our lungs. Once inside, allergens cause histamine levels to rise, which in turn triggers our immune system response. This is the point when we start showing symptoms of allergies such as sneezing, watery eyes, coughing etc.

But what role do negative ions play here? They neutralize these airborne allergens and remove them from the air. By doing so, they remove any chances for us to inhale them. Air ionizers produce these negative ions, which also have the best cleaning ability out of all types of air purifiers. This is because negative ions can capture even the smallest particles of 0.001 micrometers in size. For comparison, the smallest particles that most HEPA filters can capture are 0.3 microns in size. That number can go further down to 0.1 microns, but only for the highest grade of HEPA filters (H13-H14).

Negative ions capture allergens in the air by attaching themselves to them. Once they are attached, the allergen becomes heavy enough for gravity to pull on the ground. Once on the ground, allergens are not able to rise back into the air. And if they are not in the air anymore, we can not inhale them, which in turn prevents the buildup of histamine and an allergic reaction.

Positive effects of negative ions on the body

This is the next important part of understanding why air ionizers work for allergies. Recent new studies have shown that negative ions positively affect our bodies. In the table below I list the proven effects of negative ions on the human body. Note: In contrast to negative ions, positive ions are not good for our health (despite their name!). All of the harmful particles in the air – from allergens to dust, are positively charged.

Effects on negative ions on humans


Negative ions

Positive ions

Nervous system






Blood pressure






Oxygen consumption








Slow down







Nasal congestion



General capacity



Source: Antonio Briganti – air filtering and conditioning

Negative ions have one specialty, very relevant for allergy sufferers, and asthmatics – they lower histamine levels. The biggest difference between regular antihistamine medicine and negative ions is that negative ions lower histamine naturally, without any side effects. When your body comes into contact with an allergen, it releases histamine in your blood as a defense. An increase in histamine levels then causes all of those allergic reactions that you experience afterward. You then treat these reactions with antihistamine medications in order to lower histamine levels and the reactions that came with it. Since negative ions (in a high enough quantity) offer the same results but without side effects, many people choose to give them a try.

Proximity (or exposure) to negative ions is the major deciding factor for how much of these healing properties you can experience. In simple terms, the closer you are to the air ionizer, the more negative ions you can inhale. The more negative ions you can inhale, the better the results, especially for allergies. Why do you have to be close to the air ionizer? Because negative ions are very unstable. The moment they exit the air ionizer device they look for the first positive particle that they can attach to. The further you are away from an air ionizer, the fewer number of negative ions will reach you. And the less negative ions you can inhale, the fewer benefits you will experience.

Allergies and ozone

If you ever read anything about air ionizers, it was probably related to ozone. Yes, many air ionizers create ozone as a by product while generating negative ions. When ozone is way up in the atmosphere it is great, as it protects us from harmful UV rays. In contrast, ground-level ozone is dangerous and detrimental to our health. There are numerous health issues related to ozone, with lung irritation being the most talked about. On ground level even a small amount of ozone is problematic. It is even worse for anyone with allergies, as an even smaller concentration of ozone harms your lungs. FDA limits the amount of ozone production to 0.05 ppm for all medical devices. This is a low amount, but still not low enough to not have any effects on you – especially for allergy sufferers.

You can probably start seeing the issue here, in regards to our question of “do air ionizers work for allergies”. On one hand, you should be as close to the air ionizer as possible in order to inhale as many negative ions as possible. But on the other hand, if an air ionizer produces ozone you will experience lung irritations and other respiratory issues whenever you are in the same room as the air ionizer.

So there is no other way around it – the best solution for allergies, in this case, is always to choose an ozone-free air ionizer. No matter how tiny the ozone amount might seem, it is never worth it to risk your health. Especially because ozone actually worsens allergy symptoms and even causes asthmatic attacks. Ideally, you want to choose an air ionizer that does not produce any amount of ozone byproduct.

Do Air Ionizers Work For Allergies? – Conclusion

In we summarize everything written in this post. Yes, air ionizers do work for allergies, but under two conditions – high negative ion emission and zero ozone.

First things first, the emission of negative ions must be high enough. In general, I recommend 6-8 million negative ions per cm3/sec as a bare minimum. 10 or 20 million negative ions per cm3/sec would be an even better start for someone who suffers from allergies. A high negative ion emission will ensure that there are enough negative ions to deal with all the allergens and other pollutants in the air. Also, a lot of negative ions means that you will get to inhale more of them, experiencing the positive benefits that they can offer. Simultaneously, negative ions will keep your histamine levels in check.

Second, no ozone is a must for any allergy sufferer. Because of the harmful interaction between ozone and our bodies, you should aim for zero ozone, if possible. This is even more important for anyone that has allergies because the same adverse effects of ozone can be felt even at the smallest quantities.

If those two conditions are met, then you have a very effective tool against allergies. So effective that it can, in fact, completely get rid of all your allergy symptoms. However, If these two conditions are not met, then you have a mediocre air purifier that can worsen your allergies at worst, and improve them a little bit at best (because it will still remove at least some allergens from the air).

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The author is an Air purifier expert with overall knowledge of air and ionizers.