It is generally recognised that Australians spend 90% or more of their time indoors. Despite this, relatively little research has been done on the quality of air in our homes, schools, recreational buildings,restaurants, public buildings, offices, or inside cars.
Poor indoor air quality can result in significant adverse impacts on our health and environment. Moreover, these impacts carry a significant cost burden to the economy. The CSIRO estimates that the cost of poor indoor air quality in Australia may be as high as $12 billion per year (Brown, 1998). In recent years, comparative risk studies performed by the US EPA and its Science Advisory Board have consistently ranked indoor air pollution among the top five environmental risks to public health (US EPA, 1993).
Definition of Indoor Air
The National Health and Medical Research Council (NHMRC) defines indoor air as air within a building occupied for at least one hour by people of varying states of health. This can include the office, classroom, transport facility, shopping centre, hospital and home. Indoor air quality can be defined as the totality of attributes of indoor air that affect a person's health and well being.
A major concern with respect to indoor air quality is the use of gas cookers and unflued gas heaters. These two sources can often contribute a large percentage of the pollutants found in domestic dwellings.
Increasingly, as dwellings have become better sealed from the external environment, pollutants being released from indoor sources are being found at higher concentrations.
Indoor air quality can be adversely affected by other pollutants such as fungi, microbial contamination, house dust mites, particulates and air toxics such as formaldehyde.
Indoor Air Quality - Health Effects as a Result of Exposure to Pollutants
The health impacts of many chemical components in building materials are not well understood. Many chemicals present in indoor air environments have not been thoroughly tested and little is known about their long-term health effects (Meek 1991).
Even less understood are the health effects from constant exposure to mixtures of these chemicals (Pollak, 1993). Common health problems that result from exposure to poor indoor air quality include: sensory and skin irritation; neurotoxic symptoms; hypersensitivity and odour and taste symptoms (Berry, 1994).
The term 'sick building syndrome' (SBS) is used to describe an excess of chronic symptoms. Some short term symptoms may be described as irritation of the skin, eyes and throat. Headache, drowsiness and general irritancy are also indicators of SBS. Long term symptoms such as cancer and respiratory disease may be caused by long term, periodic exposure to chemicals such as formaldehyde and microscopic fibres such as asbestos.
Indoor air quality issues
Part B of the State of Knowledge Report: Air Toxics and Indoor Air Quality in Australia provides information on a range of indoor air quality issues, including sources, levels and effects of particular pollutants and the management of indoor air quality in Australia.
The Inside Story - A Guide to Indoor Air Quality - Office of Radiation and Indoor Air has been prepared by United States Environment Protection Agency and the United States Consumer Product Safety Commission. It is an important resource and provides a comprehensive overview of the wide range of topics relevant to indoor air quality.
It is important to be aware that the information provided in The Inside Story relates to the United States of America. For example, the regulatory agencies referred to are not relevant to Australia. In addition, there are there are some significant differences between the situations in Australia and the United States in relation to indoor air issues:
In contrast to the USA, Australia currently has no specific controls on indoor air quality - apart from workplace situations under the National Occupational Health and Safety Commission.
Significance of Radon as a pollutant
The Inside Story, and many other American publications on air quality, highlight Radon as a pollutant of concern in the United States of America. In the USA, many homes have basements, requiring excavation into rock and soil where Radon occurs naturally.
While Radon does occur in Australia, it is much less of a problem as an air pollutant because few Australian homes have basements.
Berry, M.A. (1994) Protecting the built environment: Cleaning for health. Chapel Hill:USA
Brown, S.K. (1998) Beating the $12 Billion Cost of Polluted Air. CSIRO Press Release, Ref 98/55.
Meek, S.L. (1991) 'Health Issues' in Indoor Air Quality in Homes: Synthesising the Issues and Educating Consumers. J. Laquatra & S.A. Zaslow [Ed.] American Association of Housing Educators and Building Research Council, Small Homes Council, University of Illinois at Urbana - Champaign. pp. 12-16.
Pollak, J.K. (1993) The Toxicity of Chemical Mixtures: An introduction to recent developments in toxicology. Centre of Human Aspects of Science and Technology and the Public Interest Advocacy Centre. Sydney:NSW.
US EPA (1993) 'EPA's Approach & Progress' in Targeting Indoor Air Pollution.