The Difference Between Hydroxyl Generators, Ozone Generators, And Bi-Polar Ionization

Learn the critical differentiators of these leading air purification technologies and why you should always choose a technology backed by testing and proven efficacy.

Clean air is essential for creating healthy indoor environments for your business, school, office, and organization. A significant part of creating clean air comes from the use of portable and HVAC In-line air purification systems. With thousands of air purification systems on the market, all boasting efficacy associated with advanced air purification technologies. It is hard to tell the differences, determine the technology's effectiveness, or know whether it is safe to use. Therefore, Sanalife's team of indoor air quality experts has complied a "what you need to know," comparing the differences between the top three air purification technologies; Hydroxyl Generators, Ozone Generators, and Bi-Polar Ionization.

What Are Hydroxyl Generators?

Hydroxyl Generators are a type of air purification system that produces hydroxyl radicals and oxidizers that can decompose airborne chemicals, pollutants, and organic contaminants. Hydroxyl Generators work by introducing ultraviolet light to air with a titanium catalyst to create hydroxyls out of water vapors. The resulting hydroxyl radicals (OH) can rapidly inactivate VOCs, viruses, bacteria, and other microorganisms in the air. The unique chain reaction of hydroxyl generation can form additional hydroxyl radicals, allowing the technology to reach all areas within indoor environments.

What Are Ozone Generators?

Ozone Generators are a type of air purification system that produces Ozone (O3) to help reduce the presence of airborne contaminants. Ozone's highly reactive composition of three Oxygen atoms allows the molecules to attach to airborne organic contaminants to oxidize and eliminate them. The two standard processes for Ozone generation are Silent Corona Discharge and Ultraviolet Radiation.

How It Works Ozone Generator Diagram
Diagram of How Ozone Generators Function (Source: Ionizer Hub)

Silent Corona Discharge:

Silent Corona Discharge is a form of Ozone generation that uses an electrical charge to split apart stable Oxygen (O2) molecules. As air passes through these systems, the resulting unstable singular Oxygen atoms then bond with other O2 molecules forming Ozone (O3).

Ultraviolet Radiation:

Ultraviolet Radiation is a form of Ozone generation that uses ultraviolet light (similar to the Sun) to split apart stable Oxygen (O2) molecules. Although capable of producing Ozone, when compared to Silent Corona Discharge, Ultraviolet Radiation is known to be less effective in splitting O2 molecules into singular unstable Oxygen atoms.

The Potential Dangers of Ozone Generators

Although Ozone generators can eliminate airborne organic contaminants, Ozone has long been recognized by public health organizations and professionals to impact human health adversely. According to the U.S Environmental Protection Agency (EPA), exposure to high amounts of Ozone can lead to severe respiratory issues. Such adverse health effects include lung tissue inflammation, aggravated asthma, chronic bronchitis, and increased risk of lung infections.

It is important to note that presently, U.S federal agencies have not approved the usage of ozone generators in occupied indoor environments. Strict regulation on air purifiers is primarily present in California through the California Air Resources Board (CARB). CARB-certified air purifiers meet specific guidelines to ensure they do not produce harmful Ozone levels during operation.

What Is Bi-Polar Ionization?

Bi-Polar Ionization, also commonly referred to as Needle-Point Bi-Polar Ionization, uses a similar electrical charged-based reaction to Silent Corona Discharge. This technology works by injecting positive and negative ions into the air to attract to and charge airborne particulate. In this method, Bi-Polar Ionization can only reduce airborne contaminants by causing them to fall out of the air. Similar to Ozone generators, Bi-Polar Ionization has two primary methods to generate ions; Corona Discharge and Brush Discharge.

How Bi-Polar Ionization Works Diagram
How Bi-Polar Ionization Works Diagram (Source: Modern Castle)

Bi-Polar Ionization Corona Discharge:

The Corona Discharge method is commonly used in electronic air purification systems known as "Needle-Point Ionization." Corona Discharge uses high-voltage electricity, a pointy conductive needle, and electrical wire to create a strong electrical field to ionize the surrounding air. Once ionized, typically in HVAC ductwork or within an ionizing air purifier, this technology can attract airborne particulates.

Bi-Polar Ionization Brush Discharge:

The Brush Discharge is commonly used more in portable air purifiers. The typically lower voltage of Brush Discharge reduces the ability to ionize larger volumes of air, making it less effective for HVAC system installation. Similar to Corona Discharge, Brush Discharge ionizes air by creating an electrical field. The electrical field from Brush Discharge systems occurs between two electrodes, one flat and one rounded. 

The Conundrum of Bi-Polar Ionization

Although Bi-Polar Ionization is known to be effective at reducing airborne contaminants, its method does not truly solve indoor air quality issues. With the charged ions forcing airborne particulate to fall out of the air, this technology does not capture or physically eliminate the contaminants. In indoor environments, occupant activity can resuspend the airborne particles and allow them to remain breathable in the air. Additionally, the same ions discharged from Bi-Polar Ionization can cause airborne contaminants to stick surfaces and your lung tissue. Subsequently, air ionization increases the potential for airborne particulate to be deposited within your lungs.

Does Bi-Polar Ionization Produce Ozone?

Yes, most Bi-Polar Ionization systems used in commercial environments produce some level of unwanted Ozone. However, not the same levels of Ozone Generators, the levels of Ozone produced by Ionization systems may cause similar adverse health effects. With Bi-Polar Ionization systems commonly used in occupied indoor environments, risks of associated airborne Ozone reactions may be greater. For researchers, a significant concern is how Ozone can react with Volatile Organic Compounds (VOCs). When reoxygenated by Ozone, VOCs, which are emitted into the air from cleaning products and building materials, can become airborne toxins and irritants. Without proper air filtration or elimination, high VOC concentrations are linked to additional adverse health effects.

Commercial Grade Air Purifier With Bi-Polar Ionization

Understanding The Differences In Air Purification Technology

Of all the technologies presented, each uses an advanced electronic-based method to reduce airborne contaminants. Hydroxyl Generators and Ozone Generators can both operate using ultraviolet light to create their molecular reactions. However, the Ozone created by Ozone Generators is widely recognized to have potential adverse health effects on humans. 

Additionally, most Bi-Polar Ionization air purification systems are also known to create Ozone, posing similar health effects. Bi-Polar Ionization and Ozone Generators also share in common the use of an electrical or Corona Discharge as a method to create their molecular reaction. Amongst these technologies, Bi-Polar Ionization is known to be the least effective in physically eliminating airborne pollutants, as Ionization only causes these pollutants to fall out of the air and stick to surfaces.

With these technologies in mind, it is essential to recognize the importance of choosing an air purification technology with extensive efficacy and safety testing. At Sanalife, we pride ourselves on supplying indoor air quality solutions that provide the cleanest air possible. That's why our premier air purification solutions all feature ActivePure® Technology. ActivePure® is a trusted, tested, and proven air purification technology that can rapidly reduce over 99.99% of airborne contaminants and pathogens. Contact our IAQ solutions experts today to learn why you should choose ActivePure® over Bi-Polar Ionization, Ozone Generators, and Hydroxyl Generators.

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