Healthy indoor environments

'Home' means refuge and security, a place to which we turn to replenish our energies (Ryd 1991).

Having good-quality indoor environments in our homes is important for our health.

Housing a growing population

By 2051, Victoria's population is projected to double to 10.1 million people (over 40 years).

This increase in population size is estimated to be due to natural population increase of 1.8 million people and net migration of 2.8 million people (Department of Environment, Land, Water and Planning 2016).

The quality of housing has major implications for people’s health. Population growth increases the demand for housing.

Therefore, improving housing conditions and reducing health risks in the home is essential for protecting public health and maintaining wellbeing (World Health Organization, 2018).

And of course, housing affordability and accessibility are central to supporting wellbeing.

Guidelines on housing and health

The World Health Organization's Housing and health guidelines (2018) strongly recommend that countries consider strategies for preventing or reducing household crowding, accessibility for people with functional impairments, home safety and injuries.

The guidelines also recommend safe and well-balanced indoor temperatures to protect people in climate zones with a cold season.

The guidelines also recommend that where populations are exposed to high ambient temperatures, there are strategies to protect people from excess indoor heat.

Time spent indoors

Research shows that

• Australians spend 80 to 100 per cent of their time indoors (at work and at home)
• 42 per cent of women and 22 per cent of men spend more than 80 per cent of their time at home
• time spent indoors increases with age (enHealth, 2012).

Indoor air quality

Air is a mixture of gases and small particles.

Indoor air can contain synthetic and naturally occurring substances – pollutants or allergens – that may affect health.

Whether a source of indoor air pollution is a problem or not for health and wellbeing depends on:

• the type of air pollutant (or allergen)
• the amount and rate at which it is released from its source
• the degree of available ventilation to remove it from indoors (Department of Environment and Energy, 2012).

Common sources of indoor air pollutants include various human indoor activities, household products, environmental conditions – building construction materials, ventilation, and heating and cooling systems – and external factors (from outdoors).

Indoor air pollutant levels:

• can sometimes be higher than levels found outdoors
• if high enough, can affect people’s health, and in some cases safety
• in the workplace, are managed through workplace health and safety legislation for workers and visitors to a workplace
• from household appliances are generally regulated by manufacturing design, compliance with instructions for use including maintenance and consumer legislation
• from use of consumer products are minimised by following safe use instructions on the product label
• due to personal hobbies or behaviours, including the potential misuse of materials or products can also affect indoor air quality and expose inhabitants to health hazards. This can be prevented or minimised with community information and guidance.

Vulnerability to air pollutants

Some people in the community are more vulnerable to air pollutants.

This includes the very young, older people, those with pre-existing respiratory or cardiovascular disease and those who are sensitised to a substance (allergen).

Symptoms associated with poor indoor air quality can range from acute to chronic, and from mild or generally non-specific effects (eye, nose and throat irritation, and headaches and dizziness) to more severe (asthma, allergic responses).

Exposure to some indoor air pollutants can increase the risk of developing cancer.

Victoria differs from other states and territories in that the use of unflued gas heating is limited and even prevented in vulnerable-use settings including childcare centres, schools, universities, community health centres, residential care services and hospitals.

This has been in place since 2008, as this type of heating releases water vapour, nitrogen dioxide and other air pollutants which can exacerbate respiratory conditions, including asthma (Victorian Government 2018).

Indoor air quality in Victoria

A CSIRO and Bureau of Meteorology study of indoor air pollutants in 40 typical homes in Melbourne (in temperate urban areas) in 2008 and 2009 found concentrations of indoor air pollutants lower or comparable to concentrations found in previous Australian studies (Commonwealth of Australia 2011; Cheng et al. 2011).

Weekly average concentrations of carbon dioxide, carbon monoxide, nitrogen dioxide, formaldehyde, other carbonyls, BTEX (benzene, toluene, ethylbenzene and xylene) and total volatile organic compounds were higher indoors than outdoors, whereas PM10 fine particles, ozone and fungi concentrations were higher outdoors.

In dwellings using gas appliances for cooking, levels of carbon dioxide, carbon monoxide, nitrogen dioxide, PM2.5, formaldehyde, benzene and total volatile organic compounds were higher than in households that solely used electric cooking appliances.

In addition, the effect of proximity to major roads on indoor air quality accounted for around 20 per cent of indoor nitrogen dioxide in these situations.

Only a general comparison of indoor and outdoor air pollutant concentrations occurs, since Australia does not have indoor air quality guideline values.

References

Cheng M, Galbally I, Gillett R, Keywood M, Lawson S, Molloy S and Powell J 2011, Indoor air project: part 1 main report: indoor air in typical Australian dwellings, Commonwealth Government of Australia, Department of the Environment, Water, Heritage and the Arts, Canberra.

Commonwealth Government of Australia 2011, Indoor air quality: Australian state of the environment report, Commonwealth Government of Australia, Canberra.

Department of Environment and Energy 2012, Your home: Australia's guide to environmentally sustainable homes, Commonwealth Government of Australia, Canberra.

Department of Environment, Land, Water and Planning 2016, Victoria in future 2016: population and household projections to 2051, State Government of Victoria, Melbourne.

enHealth 2012, Australian exposure factor guidance: guidelines for assessing human health risks from environmental hazards, Commonwealth Government of Australia, Canberra.

Ryd H 1991, 'My home is my castle: psychological perspectives on "sick buildings"', Building and Environment, vol. 26, no. 2.

State Government of Victoria 2018, Gas Safety (Gas Installation) Regulations, State Government of Victoria, Melbourne.

World Health Organization 2018, Housing and health guidelines, World Health Organization, Geneva.