Facts You Might Not Know about Air Purifiers

Air purifiers are becoming more and more popular, with promises to cleaner air in your home. Recent studies have shown that certain pollutants have levels that are up to five times higher indoors than outdoors, which is a concerning thought. Those who live in areas that have high levels of pollution or those who have allergies or breathing issues, often consider buying a purifier to improve the quality of the air around them.  Air purifiers can help by neutralising some of the pollutants, however they may not be as effective as you first believe. To help you become informed about air purifiers, we have collated a list of frequently asked questions, and answered them for you to give you a better understanding before you commit to a purchase. 

Facts about Air Purifiers​

Are there any downsides to Air Purifiers?

Air purifiers aim to make you healthier by making the air around you clearer, and they are considered generally safe. It is important to note however that all air purifiers do release some levels of EMF radiation. While exposure to this radiation is deemed safe, there have been studies that suggest prolonged exposure can have adverse health effects. 

Not all air purifiers are equal however, with some releasing more EMF radiation than others. Check out our blog on the best Low EMF Air Purifiers to find some brands that are safer for use in your home.  

best low emf air purifiers

How do Air Purifiers work?

Air purifiers are machines that contain a filter, or multiple filters and a fan. The fan sucks in and circulates the air from your home, while the filter traps pollutants meaning that they are no longer in the air. The clean are is then circulated back into your home. The filters in air purifiers can be made from a variety of different materials, some more effective than others – more on this later. It is important that the filters are replaced regularly in order for the Air Purifier to remain effective. Some filters are marketed as being reusable and can be washed but are difficult to maintain and may need replacing still. Therefore, it is important to look into the cost of replacement filters when budgeting your air purifier. 

What Should I look for in an Air Purifier?

As well as choosing an Air Purifier that produces a lower amount of EMF radiation, there are a few things that you should look out for.

HEPA Filters

HEPA (or High-efficiency particular air) filters use their dense fiber to remove airborne particles from the air. Almost every air purifier on the market now has this type of filter so make sure that the one you are selecting has this (or better). HEPA filters filter around 99.97% of particles down to 0.3 microns so are great at removing air pollution from your surroundings. 

Even better however is a HyperHEPA filter, which is more efficient, removing 99.5% of particles down to 0.003 microns in size – if you can find a low EMF air filter with a HyperHEPA filter, this will keep you safe from both pollution and radiation. 

Carbon Filters 

While HyperHEPA filters are great for reducing the amount of particles in the air, they are not effective in tackling gases and odors as they are not solid particles and can simple pass through the filter. Activated carbon filters can help with these however, by absorbing gas and chemical molecules, binding them to the charcoal surface area. These filters are also effective on vehicle emissions. 

Clean Air Delivery Rate (CADR) Rating

The CADR rating is a measure of the speed that your air purifier works at removing contaminants like dust, smoke and pollen from your home. For the most effective Air Purifier, look for a CADR rating of at least 300. Any level above 350 is excellent. 

Air Changes per Hour (ACH)

Air Changes per hour refers to how often the machine filters all of the air per hour. If the ACH rating is 5 then it means the air in the room is filtered 5 times every hour. If you are looking to purchase an Air Purifier, an ACH rating of 5 and above is good. However, if you have asthma or allergies such as hay fever, an ACH rating of between 6 and 8 would be best suited to try and reduce your symptoms. 

Air Purifier Size

If you are thinking about purchasing an air purifier, it is important to think about where it would be located in your home. If you are looking for the purifier to work on a lower setting, which is often quieter, then select a purifier that is designed for a room larger than the one that you are intending to put it in. 

What Should I avoid in an Air Purifier?

In addition to having filters that you should be looking for, some air purifiers have features that you will want to avoid. 

Air Ionizers

Air ionizers claim to clean the air by giving out negatively changed ions, also known as anions. These ions are meant to attract pollution particles that are positively charged. This then leads them to stick to surfaces such as walls and furniture, getting them out of the air.  Some air purifiers use this technology as their main marketing feature, but there are two issues with ionizers in the home. 

Firstly, ionizers do not get rid of pollutants – they just move them so that they stick to the surfaces of your home. They will also stick to your person, and can be breathed in, sticking to the inside of the windpipe and lungs. Build up can then lead to adverse health conditions. 

Secondly, ionizers produce ozone (O3) that can lead to harmful levels indoors when not ventilated. Ozone in the air can lead to respiratory problems, irritate the eyes and in high concentration, can be fatal.  Although air purifiers should not release ozone in high concentrations, this is something to be aware of before choosing one to purchase. 

UV Light Purifiers

UV light is commonly used in the medical sector to disinfect equipment, preventing the spread of viruses and bacteria. UVGI stands for Ultraviolet Germicidal Irradiation and is one of the most common UV methods. This method can damage the DNA of virus and bacteria cells, which destroys them. However, there are some issues with this.

Firstly, this only works if the bacteria and viruses are exposed to the ultraviolet light for some time which could be up to several house. Air purifiers that have such technology do not focus the UV light on areas long enough for them to be fully effective. 

UV lights also do not get rid of pollutants meaning that they will not effectively purify the air in your home. They also produce ozone, which as we have discussed above, can lead to health issues. 

Lastly, UV light can lead to health issues such as skin and eye damage as well as being linked to cancer. Therefore, it is best to avoid using this in your home. Better to be safe than sorry. 

Can Air Purifiers filter the outdoor air that enters your home?

Some of the pollution inside your home can originate from sources that are outside – for example fires and traffic pollution. This is usually temporary and clears quickly. Air Purifiers that use HEPA filters are most likely to be able to tackle pollution from the outdoors as they will be able to filter these particles out of the air. 

Where should I put my Air Purifier and how often should I use it?

Your air purifier will be most effective if it is placed in a room where you spend a lot of time – a living room, kitchen or bedroom perhaps. In order for it to work well, place your air purifier in a location where there is no obstruction of the air flow. Make sure that there are no large objects such as furniture close by that will block the air. 

Smaller rooms will take less time to filter than larger rooms, so therefore expect the machine to be on for longer if the space it is working in is bigger. The Air Purifier’s manual will have recommended running times to refer to. For the best results, it may be worth investing in an air quality monitor. This will allow you to measure the air quality, identifying when it is necessary to run the Air Purifier most effectively.  

Will an Air Purifier Cure My Asthma or Allergies?

Air Purifiers will not cure asthma or allergies, but they will help alleviate the symptoms associated with them. As air purifiers will reduce airborne allergens like dust, pollen and animal dander, there are less irritants in the air for asthma and allergy sufferers. Think of an Air Purifier as a preventative measure, rather than a medical cure. 

How can I improve the air quality in my home without an Air Purifier?

If you are concerned about the levels of EMF exposure in air purifiers, there are other ways to improve the quality of your home’s indoor air. In order to reduce levels of indoor air pollution in your home, the best way is to ventilate your home. You can use these tips instead of an air purifier, or alongside one. 

Vacuum your home often

Vacuuming your home will help get rid of particles. Use a vacuum cleaner that is sealed and HEPA certified as this will trap any dust instead of simply blowing it back into the air. 

Open your windows 

If you can, open your windows to ventilate your house often, as this will prevent irritants being stuck in your rooms with nowhere to go. Opening windows at opposite sides of your house with the doors open can create a cross draft that will ventilate your home even more. 

Ventilate your kitchen

As well as opening your kitchen window, use an exhaust fan to increase ventilation. This applies to your bathroom too if you have one. Make sure you switch these fans on before using other appliances like the oven, hob or shower and keep the fan on after you have finished using them. 

Minimize the use of fire

Whether this be the use of candles, smoking or wood fires inside your home any flame or burning will increase pollutants in your home. Reducing your use of these will make the air in your home cleaner. 


Air Purifiers can effectively clear the air in your home, alleviating any symptoms of asthma or allergy sufferers and reducing pollution levels. With so many air purifiers on the market, it is important to ensure that you select the correct one – look for those with HEPA and carbon filters, and high CADR and ACH levels. 

It is important to remember that Air Purifiers do omit EMF radiation, and this can lead to health implications, so remember to look at our article on the best low EMF options. If you do not want another appliance that omits this radiation in your home, there are some alternative ways to improve the air quality by using ventilation and cleaning techniques.