When the air quality outside is poor, especially in the event of bushfires or high volumes of pollution, it’s important to keep indoor air quality at its best, particularly when Australians spend 90 percent of their time indoors.[1]

Poor air quality can lead to respiratory conditions, including shortness of breath and aggravated asthma, and irritation of the eyes, nose, or throat.

There are various ways that indoor air quality can be improved, which can help manage the health of everyone in the home or office environment. For those running an air conditioning system can also assist in keeping the indoor air free from nasties that might be circulating outside.

Is it safe to run my air conditioner with poor air quality outside?

It’s a common misconception that all air conditioning systems use outside air to cool or heat the indoor air, however, this is not always the case. When the air quality is poor outside, it’s still ok to run an air conditioning system and it can assist with improving the indoor air quality.

The air conditioning system consists of an indoor and outdoor unit, which is linked by pipes with refrigerant gas flowing between the indoor and outdoor units. The outdoor unit consists of a fan, condenser coil, and compressor while the indoor unit consists of evaporator coils, a circuit board, filter, and fan.

The indoor unit pulls air into the unit, which passes the refrigerant filled evaporator coils. The refrigerant inside absorbs heat as it changes from a liquid to a gaseous state. To keep cooling efficiently the air conditioner has to convert the refrigerant gas back to a liquid again. To do that the compressor puts the gas under high pressure. All the extra heat created by compressing the gas is then evacuated to the outdoors with the help of condenser coils and a fan. As the heat is removed and the gas cools, it changes back to liquid and the process starts all again. If the unit is switched to heating mode, the process is reversed.

While air is being pulled into and blown out of the indoor unit it travels through filters, which remove dust and particles from the air. Fujitsu General’s Wall Mounted Split air conditioning systems include an apple-catechin filter which captures fine dust, invisible mould spores and harmful microorganisms that are absorbed onto the filter by static electricity, where further growth is inhibited and deactivated by the polyphenol ingredient extracted from apples.

Additionally, it allows you to control temperature and assist with humidity levels in the home. While temperature and humidity can be very uncomfortable for you, especially in summer when the air is heavy and moist, the humidity alone can cause building damage from condensation. Humidity can also contribute to mould growth[2] and radon gas[3], a naturally-occurring colourless and odourless radioactive gas.

It is highly recommended that you maintain your air conditioner by keeping the filters clean and the air conditioning system periodically serviced by a licensed technician. For more information on how to keep filters clean, watch our ‘how to’ video.



For those seeking additional ways to improve the indoor air quality, here are some tips to help keep air quality indoors at its best.

Fresh is best

When the outside air quality index is ok, and the air conditioning system is off, one way to improve the air quality indoors is to open doors and windows to let the air circulate. By moving the stale air you are replacing the oxygen, avoiding mould growth by reducing condensation, and removing dust. With bushfires and emissions from traffic and industries common in Australia, there is no guarantee that the air will be fresh and beneficial as the outside quality is susceptible to the environment. Before opening windows and doors, check the air quality index status via individual state government websites.[4]  

Cleaning up

Staying on top of household cleaning can be difficult, but when it comes to your health there are no cutting corners. Carpets and rugs can harbour chemicals and allergens such as dust mites, some of which can become airborne. Dusting and vacuuming regularly will help to remove these from circulating in your home. Additionally, wiping down benches and bathrooms can remove mould spores that may impair your air quality. You will need to clean your home regularly for this to be effective as once there is mould it can be difficult to remove.

Indoor plants

While the air outside may be of poor quality, you can improve the air indoors by introducing plants to create oxygen and remove toxins[5]. While pollen can be a major issue with some flowering plants, there are many other options, such as a Peace Lily, Spider Plant, or Devil’s Ivy that offer air purifying capabilities you may be looking for without affecting someone with a sensitivity or hay fever. Good oxygen levels assist red blood cell production so that they can be carried around the body to complete necessary functions. Without it you would feel fatigued, drowsy, irritable, and find it difficult to stay focused. It also assists to improve your immune system to fight off bacteria, viruses, and germs to keep you feeling healthy.

With an early start to the bushfire season in Queensland and New South Wales, air pollution is at risk of being poor on a regular basis, you can keep yourself healthy by taking measures to improve the air quality in your home. You may be unable to control the quality outside, but with simple steps, the indoor air quality can be kept healthy and comfortable all year round.

[1] https://www.environment.gov.au/protection/air-quality/indoor-air#:~:targetText=Indoor%20air,%2C%20offices%2C%20or%20inside%20cars.[2]  https://www.nationalasthma.org.au/news/2016/indoor-humidity 
[3] http://przyrbwn.icm.edu.pl/APP/PDF/132/app132z3-IIp051.pdf
[4] https://www.dpie.nsw.gov.au/air-quality/current-air-quality 
[5] https://www.bhg.com.au/best-air-cleaning-plants