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Should I turn on the ionizer on My air purifier?

By The Science of AIR
Page last updated: 03/23/2022 | Next review date: 03/23/2024
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The Science of AIR
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This article discusses how air ionisers work, as well as the advantages and limitations attached with them. Furthermore, we discuss how certain limitations can be mitigated, in order to bring the best out of your air ioniser.

Should I turn on the ionizer on My air purifier

Yes, you should turn on the air ioniser on your air purifier. However, this depends upon the nature of your air purifier. If your air purifier depends upon the device’s working mechanism.

If your air purifier utilises an air filter in order to remove pollutants from the indoor air and has an ioniser as an additional component, then yes. 

However, if your air purifier is just a stand alone air ioniser, then there are certain limitations you should be aware of, since they can potentially have a negative impact on your health.

Why do we need an air purifier?

Over the previous decades, the rise in air pollution has been prevalent, especially in urban areas. Air pollution is caused by both natural processes as well as anthropogenic (i.e., human-based) activities, however, the latter is the main culprit.

Activities related to rapid urbanisation, such as traffic related air pollution, emissions from industries such as thermal power plants, brick kilns, factories, etc., and other such processes have significantly contributed towards the steady degradation of air quality.

An average individual spends more than 90% of their time within an enclosement, with more than 80% of this time in an indoor setting such as offices, residents, and so on.

There have been studies that have shown that in large cities, indoor air pollution poses a higher risk on human health than outdoor air pollution.

Indoor air pollution can originate from indoor sources, such as household items, furniture, combustion of fuels, smoking, and so on.

Indoor air can also get polluted when pollution from outdoors infiltrates through openings such as doors, windows, gaps, cracks, seeps, and so on.

Amongst these pollutants, the worst is particulate matter, or simply PM. PM refers to particles in the sub-micron range that are suspended in the air. 

There are two forms of particulate matter: coarse particulate matter (PM10) and tiny particulate matter (PM2.5). PM2.5 is a prevalent problem among them.

There are many sources of PM in the ambient air. Some of the main sources include factories, power plants, refuse incinerators, fumes from automobiles, construction activities, fires and natural windblown dust.

Indoor sources include burning of  fuels, smoking, and other hobbies, such as woodworking, painting, etc.

Numerous studies have shown that exposure to polluted air containing particulate matter have been shown to cause various issues, such as:

  • premature death in people with heart or lung disease
  • nonfatal heart attacks
  • irregular heartbeat
  • aggravated asthma
  • decreased lung function
  • increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing.

Given the variety of PM present, they have various sources. These particles can originate from a variety of sources, which can be indoors, or outdoor pollution that enters through doors, windows, seeps, cracks, and so on.

This is where air purifiers come in the picture. Air purifiers mainly work on particulate matter, and rid the indoor ambient air of the PM pollution in the room, thereby cleaning the indoor air and making it safe for breathing.

They filter out particulate matter less than 0.3 microns, and the HEPA (High Efficiency Particulate Air) filters typically have an efficiency of more than 99%.

For people who suffer from allergies, asthma, or other illnesses, air purifiers can be a lifesaver. These ingenious gadgets function to remove dust, smoke, pollen, and other noxious pollutants from the air, which may cause discomfort and sickness.

What are air ionisers?

Air ionisers are devices that generate ions, which usually are anions (i.e., negatively charged ions), by using a mechanism called corona charging.

These anions interact with pollutants that have a charge. When they combine, the pollutant species become heavy and get removed from the air by settling on the ground.

Air ionisers are present as a stand alone device, ranging from different sizes, with some being suitable for large indoor spaces such as cinema halls, while some are small and portable, like in the case of air purifying necklace.

They are also an added component in air purifying devices which work by passively cleaning the air by passing it through filters.

For example, certain air purifiers with HEPA (High Efficiency Particulate Air) filters also utilise air ionisers in order to increase the efficiency of cleaning the indoor air.

Advantages of air ionisers

Air ionisers have been catching the eye, especially in the current context, where people are conscious about the kind of air they breathe.

There are certain advantages that air ionisers offer, such as:

  • Helps in relieving symptoms of allergies
  • Gets rid of odors
  • Can efficiently remove ultrafine particulate matter (UF).

Helps in relieving symptoms of allergies

Studies have shown that air ionisers are effective in getting rid of allergens, which include pollen, spores from mold, animal dander, dust, and so on.

These allergens usually have a charged surface, due to which they can attract the ions generated by the air ionising necklace.

This, in turn, causes the particles to get too heavy, due to which they cannot stay suspended in the air for a while, which in turn causes them to sediment.

This helps to reduce the number of allergens which can get inhaled, due to which an allergic response can get triggered in people.

Gets rid of odors

Air ionisers interact with odor causing molecules as well. Odor is caused when a particular pollutant interacts with the sensory neurons present in the nose lining.

This is done by different bonding sites. Hence, different substances have a distinct odor. However, these ions interact and bind to the bonding sites of the odor causing pollutants.

This, in turn, renders the pollutants ineffective, due to which the odor cannot be picked up by the nose. Therefore, air ionising necklaces are useful especially when one is passing through polluted areas such as open dumps or sewages, traffic, and so on.

Can efficiently remove ultrafine particulate matter (UF)


Ultrafine particles (UF) are a class of particulate matter (PM), which are less than 1 micron in terms of aerodynamic diameter. These are generated from various sources, such as traffic, industrial emissions, combustion, cigarette smoking, etc.

There are many studies that have established a correlation between exposure to UF and reported cases of illnesses related to pulmonary or cardiovascular systems, cancers, and in some cases, premature deaths.

This is primarily because these particles can easily penetrate all the way through the respiratory passage, and end up in the deep recesses of the alveoli, the site where air exchange between the lungs and blood takes place.

However, ions generated by the air purifier can efficiently pick out these UF particles and in a way similar to that for allergens, remove them from the ambient air.

Disadvantages of air ionisers

There are disadvantages of using an air purifier necklace, which include:

  • Low efficiency
  • Production of ozone
  • Can attract pollutants on the body

We shall discuss these in detail.

Low efficiency

Conventional air purifiers are known for their high efficiency rate of removing pollutants from the ambient air. However, the same cannot be said for air purifier necklaces.

In an experiment carried out by Shi et al, air purifier necklaces from different brands were used in a small stainless steel chamber. 

It was found that the particles had a highly variable particle removal rate, but did not perform efficiently. Some of the devices had discharged at a relatively shorter amount of time.

Production of ozone

Air purifier necklaces work by generating ions at the rate of thousands per minute. They do so by using a mechanism called corona charging, in which oxygen molecules can also get broken down, which in turn react with each other to form ozone.

Ozone is a highly reactive gaseous molecule which is naturally present in the upper layers of the atmosphere, where it absorbs the sun’s damaging ultraviolet radiation.

When present in the lower levels of the atmosphere, however, it acts as a pollutant, and can have serious adverse effects on human health, which also includes afflictions related to the cardiovascular and respiratory systems.

Ozone acts as an irritant, due to its pungent odor. It can cause wheezing, irritation in the nose and throat, runny nose, watery eyes, difficulty in breathing, and so on.

Additionally, ozone can also worsen the condition of people who are suffering from diseases such as asthma, emphysema, and bronchitis.

Can attract pollutants on the body

Necklace air purifiers work by releasing ions in the vicinity of the user. These ions can also get stuck to the skin, particularly in the face and neck region.

In turn, these ions can attract pollutants towards the user itself, and can cause deposition of pollutants on the skin of the user. This can cause adverse effects on the skin, depending on the nature of the pollutant species.

Certain toxic species, which are heavy metal pollutants like lead, can be attracted towards the skin, and can have serious implications on the health of the user.

Additionally, in case if the air contains Volatile Organic Compounds, or simply VOCs, the ozone generated from the device as a byproduct can react with the VOCs in order to give rise to secondary organic aerosols (SOAs).

These SOAs do not have any implications on human health. However, they reduce the efficiency of the air purifier necklaces, as they reduce the  particle removal performance.

Other FAQs about Air Purifiers and Filters that you may be interested in.

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Air Purifier vs Dehumidifier for Basement

Can a dirty air filter make your house smell?

Conclusion

It would be beneficial to turn on the ioniser of your air purifier, as it helps to increase the efficacy of the device to get rid of the various pollutants that are present in the indoor environment.

However, one should also understand the side effects associated with air ionisers, such as ozone production, low efficiency, and how the ions can also attract pollutants on the body.

Air purifiers with ionisers worth considering

FAQs

Where is the best place to keep an air purifier?

Ideally, you should place your air purifier in a location where the highest rate of air exchange takes place. Air exchange refers to mixing of two different types of air, which in this case refers to indoor air and outdoor air, and from one room to another.

This is because most of the pollution inside the house comes from outdoor sources. This in turn could spread to other rooms of the house. Hence, by placing an air purifier here, spread of pollutants within the house gets hampered.

Furthermore, the ideal place to keep an air purifier is to mount it on a wall, ideally 3-5 feet above the ground. This is because air moves horizontally as well as vertically, and this placement would ensure that the particles present in either air motion get successfully trapped by the air purifier.

Are air purifiers effective against coronavirus?

Air purifiers are not completely effective against the virus that causes COVID-19. Coronavirus transmits in various ways, which are:

1. Direct or indirect contact: 

The virus can be transferred by contacting an infected person’s mouth, nose, or eyes after touching an infected object or surface. 

For this type of transmission, air scrubbers are ineffective. For this type of transmission, good hygiene, which is a sort of source control, is beneficial.

2. Droplet spray in short range transmission:

When an infected individual exhales, the virus can spread through respiratory droplets (breathes, coughs, sneezes, sings, yells, or talks). 

These droplets are often bigger (>5 microns in diameter) and fall out of the air in seconds to minutes. For this type of transmission, air scrubbers are ineffective. 

This type of transmission may be prevented through social distance and masks, as well as customised filtration pressure differentials, which involves creating a negative air pressure in a certain area in order to keep all pollutants from spreading.

3. Aerosol in long-range transmission (airborne transmission):

When an infected individual exhales, little respiratory droplets (less than 5 microns in diameter) are produced. Smaller, aerosolized viruses can linger in the air for a long time and move long distances on air currents. 

For this type of transmission, air scrubbers and customised filtration pressure differentials might be beneficial.

References