Air Purifier FAQs

by Vivien Mah    

Living room with an Ionmax ION420 Air Purifier

We answer some of the most common questions about air purifiers. Whether you already have an air purifier or are just looking to buy one, you will certainly find the information below useful. 

What is a negative ioniser and is it similar to an air ioniser?

These are both names for a device that requires high voltage to ionise or electrically charge air molecules. Negative ions, also known as anions, are particles that contain one or more additional electrons, which embeds a net negative charge in that particle. Cations are positive ions which lack one or more electrons, which results in a net positive charge. A majority of commercial air purifiers generate negative ions. ESD ionisers (balanced ion generators) are another type of air ioniser that is used for neutralising static charges.

The main use of air ionisers is in air purifiers. Floating or airborne particles get attracted to the electrode, which is an effect just like static electricity. De-ionisation of these ions is conducted by earthed conductors, for example walls and ceilings. To amplify the effectiveness of this process, some commercial devices are already equipped with such surfaces.

Fun facts: The incidence of nosomocial (hospital-acquired) infections in British hospitals actually stimulated the National Health Service (NHS) to conduct research on the usefulness of anions for ensuring optimal air purification. It was revealed that recurrent airborne acinetobacter (a group of bacteria commonly found in soil and water) infections that were experienced in a ward were considerably controlled after the installation of a negative air ioniser— gradually the infection rate fell to zero. The SARS Pandemic prompted researchers to invent personal ionisers in the Far East, including Japan (where apparently a majority of such products already contain negative ion generators, even toothbrushes,refrigerators, air conditioners, air cleaners and washing machines).


Do air purifiers produce ozone?

Ionisers are not ozone generators, although both devices function similarly. Ionisers basically involve a mechanism of electrostatically charged plates that create positively or negatively charged gas ions (for example N2− or O2−) and this particulate matter gets stuck which gives an effect similar to static electricity. Ozone generators usually have been designed to produce an additional oxygen ion to an O2 molecule through either a corona discharge tube or UV light. It must be noted that even the top-most ionisers may produce some amount of oxygen ion, but the amounts produced are nowhere near enough to cause any harm at all to us. 

At high concentrations, it is possible that ozone becomes toxic to air-borne bacteria, and as a result destroys or kills these somewhat infectious organisms. Nevertheless, the desired concentrations are substantially toxic to humans and animals alike and therefore, the FDA in the United States unequivocally demanded ozone therapy to be refrained from as medical treatment, and FDA has also taken action against businesses if a failure in compliance to this rule is observed. Ozone is undoubtedly a highly toxic and very reactive gas. A daily average any greater than 0.1 ppm (0.2 mg/m³) is not suggested since the probability of lungs and olfactory bulb cells damage gets tremendously increased.


How do I know I have an indoor air quality problem?

According to suggestions of the EPA, this can be done by monitoring the changes in your health. Here are more tips you can follow to check if you have an indoor air quality problem:

  • If you experience unusual health issues after remodeling, refurnishing, performing fumigation or moving to a new place then this can be taken as an indicator of poor indoor air quality. You must immediately consult your family physician.
  • Another method for evaluating is by identifying the potential pollution creating sources for example toxic household cleaning agents/products, pets, combustible heaters, pressed-wood products and tobacco smoke, etc. 
  • Also you need to identify those areas where ventilation is insufficient. This can be done by checking the air quality such as where air feels stuffy, smelly, and there is condensation or mold growth is evident on windows and walls.
  • If you are still not sure, contact your local health department and they can send professionals for identifying your indoor air quality and suggest methods to counter this issue.


Which air purifiers are appropriate for allergy- and asthma-sufferers?

In homes where allergy and asthma sufferers reside, proper air filtration is extremely important since airborne substances that trigger allergies and asthma can easily enter your household despite all your efforts.

HEPA filtration are considered the most appropriate choice of air purifiers for such households because these are capable of removing up to 99.97% of allergens even those that are up to  0.3microns in size. You need to select the unit that has a multi-stage air filtration feature because it also contains a particle pre-filter, HEPA filter and a carbon filter, for example, the Ionmax ION420 Air Purifier


Do the air filters require maintenance?

Yes they do. However, the frequency and extent of maintenance depends upon the type of air purifier. Typically, a majority of air purifiers contain two to four filters, which should be occasionally cleaned and replaced after every 8 - 12 months so that optimal performance is ensured. Of course, if you don't use your air purifier every day, cleaning and replacement every 1.5 - 2 years is acceptable. Just check your filters every other month to make sure there isn't a huge amount of dust or dirt collecting on the filters.

Some models contain permanent air filters which don’t require replacement while others feature an arrangement of washable and replaceable air filters. Air ionisers like the Ionmax ION401 Air Purifier that don't require any replacement filters at all, as they only have blades that you need to wipe clean when dirty. 

Our newer air purifier models (like the  Ionmax ION390 Air Purifier) now have filter indicator lights that notify you when the filters need to be cleaner or replaced, so you don't have to worry about forgetting to clean your unit. 

Always read the user manual as it will include instructions and specific information on when and how to clean the filters in your air purifier. 


What are the consequences of not changing the air filters when the indicator light starts blinking?

If your air filters are not maintained properly, then the air you breathe will be polluted as well since it will not be filtered properly. This can increase the risk of health issues such as respiratory problems, asthma, allergic reactions, and other symptoms. To ensure optimum performance of your air purifier, cleaning the air filters is important. When the indicator light blinks you must change them.


What is CADR?

CADR is an acronym for air purifier measurement and stands for Clean Air Delivery Rate. CADR was introduced by the Association of Home Appliance Manufacturers. It basically identifies the volume of air filtered by an air purifier. It provides three measurements:

  • For pollen
  • For Tobacco Smoke
  • For Dust

The greater the CADR rating, the speedier the unit’s rate of air filtration.


What is a micron?

It is the short form of micrometer. Micron is one millionth of a meter and approx. 1/25,000th of an inch. It is used for measuring the sizes of air borne particles. It is crucial because usually most of the harmful air borne particles cannot be viewed through the naked eye and therefore, it becomes easier for them to be inhaled and spread throughout the household indoor environment. For instance, dust mite allergens can be up to 0.1 to 0.3 microns in size and this is a size way smaller than a single strand of human hair. A human hair strand measures around 30 to 120 microns.


Do all types of air purifiers clean similar pollutants?

Air purifiers are used for diverse and a wide range of purposes from standard air cleaning to extensive allergen removal for protecting allergy- and asthma-sufferers. Air Purifiers are of various types and come with dedicated features such as some clean air from smoke, pollen, chemicals and pet dander. If you want comprehensive particle filtration results then select a unit that has true HEPA filters. If you need an air purifier that can eliminate odour and chemicals then choose a unit that has carbon filters. For thwarting airborne germs you need to choose the more advanced units containing internal ultra violet lights along with customary filters.


Are air purifiers noisy?

An air purifier’s loudness (that is measured in decibels) is affected by a number of factors for example, the fan operating speed, the unit’s model and personal capability of noise tolerance. Usually air purifiers are equipped with multiple cleaning speeds and therefore, if the unit is operating at the highest speed then its noise will be loud and if speed is slow then noise will also be low. Consider as well where the air purifier will be used (in an office, living area or bedroom?) and your own tolerance of noise level. For example, in offices or a living area, the unit may sound very quiet even at the highest speed setting due to surrounding ambient noise, but in a bedroom at night it may sound extremely loud even when it is on the lowest or "sleep" speed setting. 


How long can an air purifier run for?

For optimal results, we recommend that an air purifier is run continuously. To prevent excessive noise and save on electricity costs, most of our air purifiers have a built-in speed management system embedded as well as timers that you can set to run for up to 12 hours. If you want to maintain the indoor air quality while you are out, then you may leave it on at low speed.


Where should I place the air purifier?

Our air purifiers are designed for purifying single rooms and therefore, it is recommended that you place your unit in a room where you spend most of your time. Check the air purifier's room size capacity before you buy. Smaller units are suitable for desks and offices, whereas larger tower air purifiers are perfect for living areas, lounge areas and bedrooms. Place your air purifier in the middle of the room instead of a corner for best air filtration results. 


How much space does an air purifier require?

Air purifiers come in various sizes to fit in to a variety of spaces such as large to small areas. Ionmax air purifiers are designed to be compact and easy to move around without taking up much floor space. They're also designed to be extra lightweight making them easy to move around different rooms. 


Which air purifier is most suitable for me?

A lot of factors are involved in this decision such as the condition you need to treat, CADR rating, control types, square footage, frequency of filter replacement, etc. However, it all comes down to your personal preference and needs. We can only inform you about the device’s functioning related information so that you always make an informed decision. You can always consult our knowledgeable sales consultants if you need further information or need expert opinion help in making this decision. Just call 03 8877 0700 or email for assistance.


Can an air purifier clean the whole house’s indoor air?

No, this is not possible since a single unit is designed to clean a room or a dedicated space area only not the entire house. Even large sized units cannot do so effectively. You need to purify indoor air quality on a room-to-room basis. Prioritise the areas where you spend most of your time such as the bedroom, TV lounge, etc. If you only spend time in one room even then it is important to purify other areas to ensure that your entire home is well-ventilated. If you are not allergic to pollen then we suggest you open your home’s windows periodically and let in some fresh air to ventilate your home and remove stagnant air. 


Why do I need an air purifier?

We spend 90% of our lives indoors yet on average, indoor air is two to five times more polluted than outdoor air. You may not think that you need an air purifier, but when you start to consider the types of allergens and pollutants that you and your family are breathing in at home, you'll be shocked. Which leads us to another frequently asked question...


What causes indoor air pollution?

If you use a gas cooker and unflued gas heater at home, you have already contributed to a large percentage of pollutants in your home. And as our homes become more better sealed from the external environment, pollutants being released from indoor sources are being found at even higher concentrations at home. 

Other pollutants such as fungi, microbial contamination, house dust mites, dust, pet dander, air toxics such as formaldehydes and volatile organic compounds (VOCs) from household chemicals also adversely affect indoor air quality. 

The health impacts of these allergens and pollutants on us may include skin, eyes, and throat irritation, headaches, drowsiness, and other, more chronic symptoms. With an air purifier, you can greatly reduce the effect of these pollutants in your home and therefore protect you and your family's health. 

You can read more about this on the Department of Sustainability's article "Indoor Air Pollution". 


What is the difference between an air purifier, a humidifier, and a dehumidifier?

They each do different things. An air purifier basically cleans the air of allergens, dust, pollutants, and harmful gases. A humidifier adds moisture to the air to combat the bad health effects of dry air. On the other hand, a dehumidifier removes moisture from the air to maintain an optimum humidity level at home. 


How do I choose what to buy?

Think of what you need to buy, why you need it, and how you will be using it. Look at extra features such as negative ionisation, deodorisation, UV sterilisation, night light, timers, water tank capacities, and other safety features that our models have. The coverage area will also be important fo you to look at, so think about what rooms in your home or office you will be using the product in. For tailored advice or assistance, just contact us and we'll be happy to help. 


Are your air purifiers ozone generators? 

No, all our products including the air purifiers are not ozone generators.


How do I clean my air purifier?

Check your product user manual for specific information on how to clean the product. Some may need to be cleaned with a cloth, while others may require replacement filters. 


How often do I need to change the filters on my product? 

You will be able to find specific information on this in your product's user manual. Some products like our ionic air purifiers will not need replacement filters. Others may need filter replacements every 6 months or 12 months, depending on the usage. For normal usage, we recommend the following:

ION390 3-in-1 filter - every 12 months
ION390 TiO2 filter - every 3-4 years
ION330 filters - 12 months
ION60, 70, 85 Ion Resin Filter - 6 months (depending on usage and quality of water)
ION90 Nano Silver Filter -  6 months (depending on usage and quality of water)



- A. Shiue, S.C. Hu, M.L. Tu (2010), Aerosal Air and Quality Research,

- N. McDowell (2003), New Scientist,

- N. Britigan, A. Alshawa, N.A. Nizkorodov (2006), Air and Waste Management Association,

- W.W. Nazaroff, B.K. Coleman, H. Destaillats, A.T. Hodgeson, D.L. Liu, M.M. Lunden, B.C. Singer, C.J. Weschler (2006), Indoor Air Chemistry: Cleaning Agents, Ozone, and Toxic Air Contaminants,


You can browse our air purifiers here: 

Vivien Mah

Vivien is a Marketing specialist with over 7 years of experience in the health and safety industry. After graduating in psychology and communications, she grew to love educating readers and unraveling complexities behind difficult topics through extensive research. Apart from sharing her love for infographics, she also posts regularly on new products, announcements, media mentions and the latest news.

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