Bi-Polar, PHI & Cold Plasma Air Purification?

Cirrus clouds

What’s The Difference Between Bi-Polar, PHI (Photohydroionisation) And Cold Plasma Air Purification?

Ions in the air are understood to play a big part in how clean and refreshing the air around us feels, but not many people are aware of their positive health benefits.

Before we talk about this, what exactly is an ion? An ion is an electrically-charged molecule in the air, formed when a gaseous atom receives enough energy to eject one of its electrons. Positive ions are those that lose an electron, whilst negative ions gain one.

This process conducts a small amount of electricity, that leads to a ‘charged’ feeling in the atmosphere.

As a measurable example of this, the proportion of ions in the air is the highest around areas of moving water such as waterfalls, rivers and by the sea, in high altitudes like the mountains, and during thunderstorms.

Compare this with the places with the lowest proportion of ions – in windowless rooms and airtight moving vehicles – and it is probably easy to understand, if not verbalise, how the presence of ions affects the air.

High concentrations of ions are associated with feeling energized, productive and refreshed, whilst concentrations below 100 ions/cm3 are understood to cause headaches, fatigue and lack of motivation.

It is useful to think about thunderstorms when attempting to understand the benefits of ions. Prior to a thunderstorm, people will often comment that the air feels ‘heavy’. This is due to a variety or factors such as air pressure and humidity, but also the amount of ozone in the air which is itself related to the concentration of ions in the atmosphere.

A thunderstorm releases huge electrical discharges that release high concentrations of ions and it is these ions that are responsible for the clean, fresh air that you are aware of after a storm.

This “sense” of cleanliness is not just a feeling, it is also a scientific fact. Ions do actually cleanse the air and make it safer for us to breathe it by removing all sort of nasty pathogens and contaminants.

There are many different technologies on the market that attempt to produce ions in order to naturally clean and purify the air inside buildings. Three of the most successful are Bi-Polar Ionization (BPI), Photohydroionisation (PHI) and cold plasma purification.

These charged ions are created and emitted into the space where the devices are located and attach themselves to biological and chemical contaminants, chemically altering the molecular structure of each atom to form new, harmless molecules.

This treated air is free to circulate in the room, and since any dangerous particles or pathogens have been altered by the generated ions, they are no longer dangerous, and the air is clean and healthy to breathe continuously.

What Is The Difference Between These Processes?

Bi-Polar Ionization

Bi-Polar ion generators work by applying a very high voltage to a specially engineered metallic needle. This results in the generation of huge amounts of ions which circulate out into the surrounding space, and which attach to any dangerous particles and chemically neutralise them.


Another ‘active‘ technology that ensures continuous cleaning of the atmosphere, PHI uses broad spectrum HE/UV light which is projected onto a catalyst and results in the formation of hydroperoxides, a particular type of ion that cleanses the air in exactly the same way as the other technologies mentioned here.  

Cold Plasma

Basically another term for BPI, cold plasma is known as the ‘fourth state of matter’ and has been used for air purification since the 1930s.

One of the benefits of cold plasma bi-polar ionization is the fact that it does not produce any ozone, making it safe for continuous air purification in any populated building.

What Makes These Technologies Important Now?

Since the global outbreak of COVID-19, scientists and researchers have been working hard to find ways to limit the spread of the virus. Studies seem to indicate that human coronaviruses including SARS and COVID-19 are able to live on surfaces for much longer than first thought – up to nine days – without disinfection measures.

What is understood, though, is that the virus can be deactivated using certain surface disinfection compounds. The most effective are those containing 62-71% ethanol, 0.5% hydrogen peroxide or 0.1% sodium hypochlorite, which effectively neutralise the virus within just 1 minute.

Increasing the concentration of ions in the air, using one of the technologies listed in this blog, results in the same benefits of the disinfection methods listed above, but in safe concentrations that destroy these dangerous pathogens, whilst still remaining safe for humans to breathe in 24 hours a day.

Other forms of air purifiers rely on UV-C light, filters that merely trap the virus, or produce an unacceptable amount of ozone, making these methods unsuitable for a safe and clean living or working environment.

In a presentation from Better Air Indoors, it is explained how a sneeze test was able to prove the unique capabilities of PHI technology in destroying airborne contaminants.

In the study, it was found that 99% of all germs emitted from the test subject, travelling at 100mph, were killed before they had travelled 3 feet.

This ability is unique to this type of technology as it is so efficiently circulated via the fan system present in devices like the Airius PureAir. It is easy to visualise why an effective air purification device needs not only needs to effectively generate ions, but also ensure they are distributed evenly throughout the living space. Without a fan assisting the circulation process, the ions merely spread slowly through diffusion, resulting in inefficient and uneven cleansing of the surrounding air.

Researchers agreed that there is no passive technology capable of killing viruses and bacteria this effectively.

Why Choose PureAir Plus?

The Airius PureAir series is already a favourite amongst businesses and those running large workspaces, thanks to its ability to generate 24/7 air purification. The PureAir Plus is the next step forward in this technology, using cold plasma BPI to ensure that there is also no ozone generated by the process, creating an entirely healthy and safe way to purify the air.

Whilst chemical disinfectants do work to neutralise pollutants on surfaces and in the air, people are more aware than ever of the dangers of allowing unnatural chemicals and cleaners onto and into their bodies.

Using technology in place of chemicals as a way to ensure a clean environment and fresh, pure air offers businesses a way to protect staff and customers, keep food preparation areas sanitary and even boost workplace productivity!

That’s why we suggest the PureAir Plus as the natural choice for any growing business in the wake of the global pandemic.

To find out more, or if you have any questions, please call us on 01202 554 200 or visit us at