Effective ventilation can improve indoor air quality and protect the health and wellbeing of your loved ones

Improve indoor air quality

Despite Australia’s love affair with the great outdoors, it is estimated that Australian’s spend about 90% of their time indoors (1). Be that at work, school or at home – it’s a significant percentage. Given this statistic, are we paying enough attention to the quality of the air we are breathing when indoors? 

Indoor air and pollutants

Air is an invisible mixture of gases, it contains important substances such as oxygen and nitrogen that we need to survive. Air may also contain pollutants, these come in the form of gases or particles and can occur naturally or come from man-made sources. Generally, pollutants enter the body through breathing, swallowing and absorbing. Breathing in only small amounts of air pollutants can have a detrimental effect on our health if they are continually entering the body over a long period of time (2). Here are some of the most common indoor air pollutants : 

Biological Pollutants

Biological contaminants include bacteria, viruses, animal dander and cat saliva, house dust, mites, cockroaches, and pollen. There are many sources of these pollutants. 

Combustion pollutants

These include carbon monoxide, nitrogen dioxide and sulfur dioxide. Combustion pollutants can get inside your home from fireplaces and heaters burning wood, gas cooking appliances, outdoor air, and exhaust from cars in garages. Combustion products from different sources can add together and build up in poorly ventilated rooms to levels that could affect your health. 

Volatile organic compounds (VOCs) 

Volatile organic compounds (VOCs) are chemicals (containing carbon) that evaporate into the atmosphere at room temperature. They often have an odour, and are present in a wide range of products used around the home and office. These include paints and solvents, aerosols, cleaners and disinfectants, air fresheners, automotive products, building materials, new furnishings, office equipment such as printers and copiers, glues and adhesives. Long term effects of exposure to VOCs are still being fully understood but common immediate symptoms include eye and respiratory tract irritation, headaches and dizziness. Studies have found that levels of VOCs average 2 to 5 times higher indoors than outdoors (3) and levels in poorly ventilated rooms increase with increasing temperature (4).

How to minimise exposure to indoor air pollutants and improve indoor air quality 

Air pollutants in the home are unavoidable but we can minimise our exposure by taking some simple measures.  

  • Good home hygiene and reducing humidity levels in the home will help minimise the growth of biological pollutants.  Adequate ventilation and good air distribution will also help. Expella’s range of all-in-one ventilation kits and humidity sensors help keep humidity under control. 
  • Ensure rooms that are heated or contain gas appliances (e.g kitchens) have adequate ventilation, vent appliances and fireplaces to the outdoors (via a flue, chimney, exhaust fan or rangehood) where possible.
  • Keeping indoor areas well ventilated and preventing them from getting too hot will help to reduce the effects of exposure to VOCs and will limit the need to use products that contain VOCs such as aerosols and air fresheners.

Other indoor air quality issues and how to solve them 


According to Passive House Institute, the ideal indoor air temperature for optimal comfort and wellbeing is 21 degrees celsius. When it is too cold or hot inside our sleep can be affected. High indoor temperatures can also reduce our productivity and cause drowsiness, while low temperatures can suppress our immune systems and contribute to the spread of airborne microbes such as those that cause the common cold. Expella offers ventilation solutions that can assist with maintaining steady indoor temperatures. These include Expella’s range of Heat Recovery Units that help maintain a stable indoor air temperature with minimal energy consumption. 


It’s important to strike the right balance of humidity indoors, if humidity is low and the air is too dry your nose, eyes and throat can become irritated; if humidity levels are too high it can lead to the growth of mould and dust mites (both thrive in damp, warm environments) which may trigger allergies and affect our respiratory health.

A relative humidity of 30-50% is generally recommended for homes (5). Quality ventilation products have been proven to assist in keeping humidity levels under control. Products such as Expella’sCeiling Mounted Humidity Sensor provide a simple automated solution to maintain the desired indoor humidity level.



1. https://www.environment.gov.au/protection/air-quality/indoor-air

2. page 9, A guide to indoor air quality in the home for buyers, builders and renovators http://www.glenelg.vic.gov.au/files/A%20Guide%20to%20Indoor%20Air%20Quality.pdf

3. https://www.epa.gov/indoor-air-quality-iaq/volatile-organic-compounds-impact-indoor-air-quality

4. Page 16 http://www.glenelg.vic.gov.au/files/A%20Guide%20to%20Indoor%20Air%20Quality.pdf

5. https://www.epa.gov/indoor-air-quality-iaq/biological-pollutants-impact-indoor-air-quality

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