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How Building Biology Principles Affect Indoor Air Quality

By September 21, 2015May 8th, 2021No Comments

Building Biology Resource Centre

How Building Biology Principles Affect Indoor Air Quality

This article was written by Raphael Siket and published in Green Magazine. It discusses sustainaility and how Building Biology plays a vital role in indoor air quality. Lifestyle decisions we make in the buildings in which we live and work have a profound impact on our health and that of the planet as a whole. This article discusses how simple practical changes can have very postive effects.

29 October 2008


On average 90% of our time is spent indoors. This makes us very dependant on the quality of our indoor air.

“So what?” you may think?

Considering we take about 12 – 14 breathes per minute at rest (more when we exercise, work or are stressed) means we breathe 10 000 – 18 000 litres of air per day. Children breathe more rapidly than adults and inhale 50% more air per pound of body weight. This makes them a lot more susceptible to air contaminants than adults.

There are many enforceable Australian standards relating to outdoor air pollution but only some voluntary guidelines relating to indoor air quality.

On average indoor air can be up to 6 times more polluted than outdoor air.

Poor indoor air quality has been linked to health effects ranging from chronic fatigue, headaches, asthma, allergies and diabetes to lung cancer and heart disease.

So what are the sources of indoor air pollution and how can we improve the quality of the air we breathe?


A simple and effective way to improve indoor air quality in the house is removing your shoes before you enter. Shoes collect an enormous amount of pollutants during the day (just think of those visits to the public toilet) and then we walk them into the house. When designing a new house make provision for a mudroom (air lock) which is a space at the entrance of the home in which shoes, umbrellas and coats can be kept. This will also provide an extra air space and help with insulation.


Good ventilation is also one of the most important aspects of ensuring better air quality. Opening windows is free and an easy way to improve ventilation. It is important that all the indoor air is replaced with “fresh” outdoor air as often as possible. Air quality problems often arise in winter when doors and windows remain shut for long periods of time and heating gives rise to dry stale air.

Sealing a building to prevent heat loss is certainly energy efficient. In California, however, they have found that this has given rise to sick buildings. A building is your 3rd skin (clothes being your second) and as such needs to be able to breathe otherwise mould can often become a problem. This does not mean that the house must be draughty (absolutely not) but it does mean breathing must be
controlled. Use natural paints that are vapour permeable (breathable) but water resistant. Use natural oils (breathable) to treat timber floors and choose building materials that have a good capacity to absorb and release moisture (timber for example).


Radiant heaters are a healthier option as opposed to convection heaters (e.g. gas ducted systems). Any heating system that is fan forced (small and large) disperses air pollutants and produces an unhealthy heat. Other healthier heating options that can be explored include utilising the heat from hot water
pipes as well as smart building design and material use.


Building materials, furnishings and finishes are some of the largest contributors to indoor air pollution. New paint, rubber underlay, many floorboard treatments, kitchen cabinets (pressed wood products), foam cushions and furnishings are just some sources of what is known as volatile organic compounds (VOC’s). Synthetic chemical compounds used in glues, resins, stain treatments, dyes and many building materials will off-gas into the indoor air to a great degree in the first 8 weeks and continue to a lesser degree for years to come. Just think about how long that new car smell lasts. This is why it is critical to make informed
decisions with regards to all materials and finishes used in the construction or renovation of a building. This is also the case when choosing your clothes, bed, mattress and linen. Dust mites cannot live in 100 % natural latex (from the rubber tree) mattresses and organic fair trade cotton linen is a great alternative to conventional linen.

Personal Care

Perfumes, creams, nail polish, nail polish remover and cosmetics contain a cocktail of synthetic chemicals that will once again add pollutants to the air you breathe. Try to minimise the amount of perfumes and cosmetics used and explore more natural alternatives (which have come a long way).


What you use to clean and how you clean plays a large role too. By law ingredients of cleaning products do not have to be listed and this makes it very difficult
to know what is being released into the indoor air space. Microfibre cloths are now highly technologically advanced and are proven to physically remove contaminants from a surface when dampened by water only. There are also more choices available today with regards to more natural and environmentally sound cleaning products.

Plants help to naturally filter polluted indoor air.

Some species demonstrate an astonishing capability for absorbing particular toxic air pollutants as root microbes convert these pollutants into food for the plant. They also release water vapour into the air through their leaves in a process called transpiration. Amazingly they do this at a higher rate when the air is dry and at a lower rate when the air contains more moisture.

They therefore work at naturally maintaining an ideal level of relative humidity.

Bill Wolverton was involved with NASA in studying the effect of plants on indoor air quality for over 20 years and some of the plants that he found to be highly beneficial are listed below:

The Bamboo Palm (Chamaedorea seifrizii)

Rubber Plant (Ficus robusta)

English Ivy (Hedera helix)

Peace Lilly

Some other highly beneficial plants that will however require more

Gerbera Daisy (Gerbera jamesonii)
Florist’s Mum (Chrysanthemum morifolium)

Kimberley Queen (Nephrolepis obliterate)

Boston Fern (Nephrolepis exaltata)

A good quality mechanical air filter can greatly improve the indoor air quality.

Small changes can make remarkable improvements to the surrounding air.

It is not about changing entire lifestyles to improve indoor air quality but rather realising how lifestyles affect air quality and general wellbeing.