Ionization: why this technology isn’t enough on its own to purify your home

Standalone air ionizers have become more popular in recent years in an effort to achieve cleaner indoor air. Many individuals use them as a way to combat indoor air pollution, specifically fine particle pollution. These units emit negative ions (negatively-charged) which bind to air pollution molecules (positively charged), weighing them down and deposing them onto room surfaces, reducing the likelihood of them being inhaled by our lungs. Since these dangerous particles are not actively removed from the space with a standalone ionizer, an air purifier with a multi-stage filtration system serves as a necessity to purify the air, a powerful, multi-barrier system where ionization acts strictly as a supporting player. How does an air ionizer work? Read on to learn more about ionizers and why improving indoor air quality requires a more robust, multi-layer filtration system in order to achieve truly clean air.

How does an air ionizer work?

The science behind air ionization

Air ionizers (or negative ion generators) are devices that act as air cleaners by using a technology that generates high-density negative ions (negatively-charged particles, also known as “negative air ions”) into the air. These particles seek out and attach to positive ions (positively-charged particles, also known as “positive air ions”), ultimately altering their charge and weighing them down. With the negative ions clumped together alongside the positive ions, they then fall to the ground or on surfaces where they no longer pose danger of being inhaled and entering the body. To avoid pollutants sticking to surfaces, some air ionizers contain intentional plates installed in the ionizer’s filter which act as conductors, pulling the particles back to the unit (1,2). The end goal of these units is to use negative air ionization to remove pollutants and improve indoor air quality, protecting our health from the dangers of air pollution.

Read more about air ionization technologies here.

How do negative and positive ions differ?

Although we may not realize it, our environments are bathed in different electrically charged particles. We encounter two types of ions throughout our lives: positive and negative. Surprisingly enough, despite their name, studies show that positive ions are associated with polluted environments and adverse effects on health. Negative ions are associated with clean air and positive well-being.

Despite whether or not we live in an urban or polluted environment (where positive ions are the most present), we are constantly surrounded by positive ions. They are generated, sometimes in large quantities which are then released into the ambient air, by our screens, household appliances, tobacco usage, or even heating systems. In enclosed spaces, they can quickly accumulate in the air and on surfaces (in your house or flat, an office, or car). Regular positive ion exposure can cause various unpleasant health symptoms, some of which include fatigue, headaches, nausea, or a general feeling of malaise.

Negative ions, on the other hand, make us feel good. Some ways by which they have a positive effect on our physiology are by 1) promoting exchanges between cells with electrically charged membranes, 2) encouraging the penetration of oxygen in the lungs (which, as you may remember from chemistry class, is negatively ionized), and 3) stimulating enzyme action and neuromediator secretion (serotonin) and hormones (cortisol). The presence of negative ions in our surroundings can decrease our levels of stress, improve our concentration, help us sleep more easily, and/or make us feel great in general. Negative ions are commonly found in natural settings such as the mountains, the seaside, the forest, or even places that are basked in sunlight. As expected, these are places where we generally feel at peace.

SEE OUR PRODUCTS

 

What are the benefits of air ionizers?

Ionization technologies allow you to harness negative ions’ ability to adhere to fine particles and remove them from your breathing air, thus, improving indoor air quality, sleep, and the occupants’ ability to breathe clearly. Of course, to avoid adverse respiratory health effects, you must ensure that your air cleaner is ozone-free certified. (Eoleaf’s devices are all ozone-free certified!).

A 2018 systematic literature review discovered that one benefit using negative ion generation in air purification is that negative ions are effective in reducing airborne pollution of multiple types, resulting in improved air quality. Firstly, unlike standalone air ionizers, air purifiers containing ionization technologies work to alleviate allergy symptoms for those suffering from allergies (removing both fine and coarse particle allergens like dust and dust mites, pollen, pet hair and dander, and mold and its spores). One of the studies analysed found that air cleaners with ionization technologies reduce airborne dust counts by 46%, improving allergies (5). The review also made some dramatic findings in other studies regarding negative ions’ ability to reduce particulate matter (PM) concentrations:

• Negative ions reduced PM concentrations from 800 µg/m3 to 50 µg/m3 in a chambered environment (6) 

• Within one hour, more than 80% of particles sized 0.1 or 1 mm were removed (7)

• Within six minutes of negative ion treatment, 93 to 97% of smoke particles were removed (8)

• Negative ions can remove around 95% of respirable particulate matter found in indoor air (9)

Other studies, particularly one 2022 study, analysed evidence of an ionizing air purifier’s ability to fight against bacteria and viruses in a classroom. It found that, with five devices installed in the classroom purifying the air, infection risk of bacteria and viruses was reduced by 23% thanks to the presence of ionization technologies (10).

Furthermore, ionization technologies are particularly useful in removing certain fine particulates, particularly those generated by tobacco smoke. 

Can air ionizers remove allergens?

Whether or not air ionizers are able to remove allergens depends upon their particle size and their behavior in the air. Allergens in the air span a wide range of sizes, falling anywhere from 1 to 100 microns. Common allergens and their diameters can be found below:

• Pollen grains: 10 to 100 microns

• Dust mites feces (the most common source of dust allergies): 10 to 40 microns

• Mold spores: 2 to 20 microns

• Pet dander: 1 to 10 microns

Ionizers are known for their action against fine particle pollution (PM10 or smaller), especially those generated by smoke. Ionization efficiency decreases as particle size increases. That said, ionization is the most effective against pet dander due to its small size and lightweightedness. Since pet dander floats indefinitely, it has a high likelihood of colliding with the negative ions emitted by the ionizer. Ionizers are considered to have a moderate-to-high efficiency against mold spores (note that ionizers do not kill mold spores, however!). Ionization has a low-to-moderate efficiency against dust mite feces, and the lowest efficiency against pollen (which is fairly heavy and clumps together, quickly falling to the ground and sticking to surfaces), making it important to invest in a multi-step air purifier when combatting seasonal pollen allergies indoors11-13.

What are the drawbacks of air ionizers?

Standalone ion generators (or negative air ionizers), referring specifically to devices not offering any additional filtration technologies, do have their drawbacks. 

However, there are dangers of ozone generators and uncertified ionizers. Generally speaking, air ionizers simply displace fine particles and cause them to fall to the ground or on surfaces rather than entirely removing the pollutants found in indoor air pollution. While this does provide some protection for your lungs, these particles can easily be disturbed and swept back up into your breathing air. Regular cleaning is, as a result, an absolute necessity.

Additionally, when used as the sole technology in an ionizer device, ionization cannot combat dangerous airborne gases (volatile organic compounds or VOCs) or odours. They are also incapable of removing coarser particles like dust, pollen, and mould spores from the air. This makes them an ineffective choice for individuals who are trying to fight allergies and/or improve lung health and reduce asthma symptoms, for example.

• Asthma attacks are often triggered by airborne allergens like dust, pollen, and mould and its spores. It is important for a device to target these allergens if the goal is to alleviate asthma symptoms and reduce asthma attack frequency.

One of the biggest concerns about ion generators is that many of them produce ozone as a byproduct if uncertified. Ozone, a secondary pollutant and powerful respiratory irritant, reacts with other air pollutants in the presence of sunlight. Ozone exposure may have many adverse health effects including throat irritation, coughing, difficulty breathing, shortness of breath, chest pain, and reduced lung function in the long term. It may also aggravate asthma symptoms and asthma attacks, as well as other respiratory conditions like chronic obstructive pulmonary disease (COPD) by inflaming the lungs.

A 2008 study found that ozone-emitting ion generators ‘initiate reactions with certain unsaturated organic compounds’, leading to the production of ultrafine and fine particles and free radicals (4). Rather than removing pollutants from the air as they claim to do, when ion generators emit ozone, they counterproductively add pollutants to the air, putting your health at risk.

What is the difference between standalone ionizers and air purifiers?

While both air purifiers and ionizers are designed to treat indoor air pollution, these technologies use different mechanisms to handle air pollutant particles found in indoor air pollution. Ionizers (or ionic air purifiers) emit negatively-charged atoms that bind to positively-charged air pollution molecules, weighing these particles down, changing their charge, and causing them to fall to the ground. Air purifiers (also referred to as air cleaners), on the other hand, employ a powerful fan to mechanically force polluted air through one or more air filtration filters and/or technologies, capturing or neutralizing air pollutants permanently to clean the air.

Are ionizers safe to use?

Ionizers are typically not recommended by major regulatory bodies like the EPA and the WHO due to their questionable safety standards. Many ionizer devices generate ozone (especailly negative ion generators that are not certified ozone-free), causing lung irritation and harmful effects on the respiratory system. Additionally, exposure to ozone may lead to other adverse health effects like throat irritation, breathing difficulties, shortness of breath, and chest pain. Since ionizers do not trap or remove airborne pollutants and simply weigh them down to the ground or on surfaces, untrapped fine particles aggravate asthma and other respiratory conditions in users who are particularly vulnerable.

Instead, it is highly recommended to invest in an air purifier that is both certified ozone-free and certified medical-grade. Medical-grade air purifiers, like those offered by Eoleaf, are guaranteed to remove 99.97% of all air pollutants down to a size 0.01 microns, ensuring that pollutants are captured and destroyed rather than just displaced.

How to maintain an air ionizer?

Every model of air ionizer is a bit different depending upon its features, as is its upkeep. Following a regular maintenance and service schedule is an essential part of maintaining any device as it maintains long-term peak performance. Below is a general chronological guide for maintaining an air ionizer.

• Every 2-4 weeks: according to the average ionizer user manual, the regular cleaning of ionizer pins must be performed. The unit must be turned off and the pins wiped gently with a microfiber cloth. This prevents drops in performance and energy efficiency.

• Every 1-2 months: wash reusable collection plates. If your ionizer uses an electrostatic collection plate rather than a physical filter, it needs to be washed regularly to remove accumulated allergens.

• Every 12 months: perform filter replacements. Although this varies significantly between models, multi-stage systems that do have a physical filter, like those found in all Eoleaf devices, must be replaced at regular intervals. In these cases, there is no tedious pin cleaning or bi-weekly scrubbing. Here at Eoleaf, our air purifiers require one filter change every 12 months on average. The process is low-maintenance and takes less than a minute but is an essential part of ensuring optimal performance and sustainability features.

To read more about Eoleaf’s maintenance and troubleshooting FAQ, refer to our dedication section on our website.

Where to buy air ionizers?

As you begin shopping around for a high-quality device to improve your indoor air quality, there are multiple factors to consider. Budget considerations must be balanced with long-term value when making your investment in an ionizer. Hybrid units that provide the most modern and effective technologies available on the market, like the 8-step air purification technology offered by Eoleaf devices, ensure a healthier indoor environment. Eoleaf’s user-friendly website makes it easy to shop for the best air purifier for your needs using our detailed product pages. You can also compare prices between models. On our secure check-out, you will be able to conveniently calculate international postage and delivery costs. We offer reliable and easily trackable shipping to ensure that your air purifier arrives safely and quickly. Refer to reviews from our happy customers here.

Our high-end products deserve high-end customer service! For any questions in placing your order, contact our human, knowledgeable customer service team. You can also refer to our privacy policy here.

Eoleaf’s ionization feature

(The article continues below)

 

Eoleaf air purifiers are two-in-one devices, serving as both purifiers and air ionizers for optimal improved indoor air quality. Our design is simple, using a powerful fan to pull in polluted air and the same powerful fan to recirculate purified air back into your space.

How does the ionization feature work?

Our devices use bipolar needle ionization technology with a voltage of 6.0 kV. This technique was developed over twenty years ago and does not emit harmful levels of ozone, or does so only at an extremely low level, unlike corona discharge ionization.

The ionization technology used in our products is particularly powerful. We use an innovative design that uses eight separate conduction filaments, a feature that generates more than 20 million ions per cm3, 6.3 million at a distance of 1 metre and 0.5 million at a distance of 3 metres, all with a total range of 5 metres.

With Eoleaf’s air purifier models, when you turn on the device, the ‘ionization’ feature is activated by default. Simply press the ‘Anion’ button on the control terminal to deactivate or reactivate it. When the function is activated, the icon appears at the top left of the screen.

Ionization is just one part of Eoleaf’s 8-step air filtration technology. Our devices also offer HEPA-certified filters, activated carbon filters, bamboo filters, UVC sterilisation technologies, and photocatalysis technologies all in one, convenient filter block!

• Note: HEPA air purifiers guarantee filtration of 99.97% of air pollutants down to a size of 0.01 microns. Keep in mind that HEPA air purifiers that claim to be ‘HEPA-type’ do not undergo the same third-party testing and cannot be guaranteed to filter the same amount of pollutants that a certified HEPA air purifier can. 

Eoleaf’s devices filter out the following indoor air pollutants:

• Germs (bacteria and viruses like COVID-19)

• Allergens (pollen, dust, dust mites, mould and its spores, pet hair and dander)

• Fine particle pollution (PM10, PM2.5, PM0.1)

• Chemical pollution (like VOCs)

• Unpleasant odours thanks to its activated carbon filter

Where should you place your air cleaner?

You might be wondering: where is the best place to install my air cleaner to benefit most from the purified air it brings? A location where the air will circulate around the device, preferably in the centre of a room, is ideal. We recommend living rooms or bedrooms since this is where we tend to spend the most amount of time in our homes. The room in your home where you tend to spend the most amount of time is best! Read more about ideal air purifier placement here. 

Also, be sure that your device is free of obstacles and that nothing blocks its fan inputs or outputs. Using the device for 2 to 3 hours per day in your home should be sufficient for most needs, but if you are prone to allergies or own a business, leaving it running is advised.

Frequently asked questions: everything you need to know about air ionization

How does an air ionizer work on a daily basis?

An air ionizer works by dispersing negative ions into your indoor air. These negative ions, which are negatively-charged air molecules, cling to air pollutants, which are typically positively-charged air molecules. Binding to air pollutants weighs them down to the ground where they are less likely to be inhaled.

What are the main biological benefits of negative air ions?

Exposure to negative ions in the air has been associated with multiple benefits on health. According to scientific studies, improved air quality as a result of negative ions results in improved sleep quality and duration and improved lung and respiratory health. However, it is essential that the ionizer be certified ozone-free.

Can ionizers remove odours from the air?

No. Unless it is a dual ionizer-air purifier, ionizers alone cannot combat gases or odours because they are not equipped with technologies capable of doing so (activated carbon filters). Devices like Eoleaf’s, on the other hand, are 2-in-1 air purifiers-ionizers, making them effective at removing air pollutants, odours, and chemical pollution like VOCs. 

Can negative air ionization eliminate complex viruses and bacteria?

Negative air ionization helps reduce airborne pathogens, including some viruses and bacteria, by charging them so that they cluster together and become easier to capture by an air purifier’s other technologies. Ionization itself, however, is not sufficient in effectively capturing and destroying complex pathogens like SARS. When used in combination with other technologies, like a HEPA H13-certified filter, the ionizer pre-charges the particles which are then physically trapped by the HEPA H13 filter. In Eoleaf air purifiers, UVC sterilization is then employed to inactivate or kill viruses, bacteria, and other microorganisms.

What is the difference between an ionizer and an ozone generator? Which one is best for asthma and severe allergies?

Ionizers work by generating and releasing negative (negatively-charged) ions into the air. Negative ions are attracted to positive ions that are often found in air pollution. Negative ions bind to positive ions and either disintegrate them or pull them down to the ground, far away from our lungs. ionizers are completely safe when they are certified ozone-free.

An ozone generator works by taking in oxygen (O2) from the air and giving it a strong electrical charge. The electrical charge forces oxygen molecules to arrange into ozone (O3). Studies performed on ozone generators have found them to be unsafe because ozone does not react with common household pollutants. Read more here.

Using an ionizer in tandem with other technologies, specifically a HEPA-certified filter, is essential in combating asthma and severe allergies. Ionizers are unable to trap and remove allergens and other pollutants from the air; rather, they weigh pollutants down to the ground, but these pollutants are still present in your living space. HEPA filters will capture pollutants generated by dust, pollen, smoke, pet hair and dander, mold and spores, and more.

Can ionizers help with asthma or other respiratory conditions?

Yes! Ionizers help to remove irritating fine particles from the air. These fine particles aggravate asthma and other respiratory symptoms. When these particles are no longer present in the air, it significantly helps symptoms to subside. However, in order to guarantee protection and improve symptoms, an air purifier with multiple air purification technologies is much better suited. Depending upon the model, these technologies work to remove all types of indoor air pollution that may lead to aggravated allergy or asthma symptoms.

Do uncertified air ionisers produce dangerous levels of ozone?

Some ionizers produce ozone, particularly those that use corona discharge that break oxygen molecules down into dangerous secondary pollution gases. Ozone is an irritating air pollutant that may lead to harmful health effects like coughing, throat irritation, difficulties breathing, and chest tightness, among others. Be sure that your ionizer is certified ozone-free before purchasing which guarantees that it produces either no or negligible levels of ozone.

 

Resources

1 Cheng Qian 2021 J. Phys.: Conf. Ser. 2029 012026

2 What are ionizers and other Ozone Generating Air Cleaners?. Environmental Protection Agency. (2023, April 10). https://www.epa.gov/indoor-air-quality-iaq/what-are-ionizers-and-other-ozone-generating-air-cleaners 

3 Phys.org. (2021, March 16). Study uncovers safety concerns with Ionic Air Purifiers. Colorado State University. https://phys.org/news/2021-03-uncovers-safety-air-purifiers.html 

4 Waring, M. S., Siegel, J. A., & Corsi, R. L. (2008). Ultrafine particle removal and generation by Portable Air Cleaners. Atmospheric Environment, 42(20), 5003–5014. doi:10.1016/j.atmosenv.2008.02.011

5 Jiang SY, Ma A, Ramachandran S. Negative Air Ions and Their Effects on Human Health and Air Quality Improvement. Int J Mol Sci. 2018 Sep 28;19(10):2966. doi: 10.3390/ijms19102966. PMID: 30274196; PMCID: PMC6213340.

6 Niu J.L., Tung T.C.W., Burnett J. Quantication of dust removal and ozone emission of ionizer air-cleaners by chamber testing. J. Electrostatics. 2001;51:20–24. doi: 10.1016/S0304-3886(01)00118-8.

7 Lee B.U., Yermakov M., Grinshpun S.A. Removal of fine and ultrafine particles from indoor air environments by the unipolar ion emission. Atmos Environ. 2004;38:4815–4823. doi: 10.1016/j.atmosenv.2004.06.010

8 Sawant V.S., Meena G.S., Jadhav D.B. Effect of negative air ions on fog and smoke. Aerosol Air Qual. Res. 2012;12:1007–1015. doi: 10.4209/aaqr.2011.11.0214.

9 Sawant V.S. Control of respirable particles in indoor air with portable negative air ion generator. IOSR J. Environ. Sci. Toxicol. Food Technol. 2013;3:28–31. doi: 10.9790/2402-0332831.

10 Ren C, Haghighat F, Feng Z, Kumar P, Cao SJ. Impact of ionizers on prevention of airborne infection in classroom. Build Simul. 2023;16(5):749-764. doi: 10.1007/s12273-022-0959-z. Epub 2022 Dec 2. PMID: 36474607; PMCID: PMC9716175.

11 Grinshpun, S. A., Mainelis, G., Trunov, M., Adhikari, A., Reponen, T., & Willeke, K. (2005). Evaluation of ionic air purifiers for reducing aerosol exposure in confined indoor spaces. Indoor Air, 15(4), 235–245. https://doi.org/10.1111/j.1600-0668.2005.00364.x

12 Pushpawela, B., Jayaratne, R., Nguy, A., & Morawska, L. (2017). Efficiency of ionizers in removing airborne particles in indoor environments. Journal of Electrostatics, 90, 79–84. https://doi.org/10.1016/j.elstat.2017.10.002

13 U.S. Environmental Protection Agency. (2018). Residential Air Cleaners: A Technical Summary (3rd ed., EPA 402-F-09-002). Office of Radiation and Indoor Air, Indoor Environments Division. https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home