Human Settlements Theme Report
Australia State of the Environment Report 2001 (Theme Report)
Lead Author: Professor Peter W. Newton, CSIRO Building, Construction and Engineering, Authors
Published by CSIRO on behalf of the Department of the Environment and Heritage, 2001
ISBN 0 643 06747 7
Liveability: environmental quality (continued)
Indoor air quality (continued)
The daily pathways of human activity will dictate the levels and duration of exposure by individuals to the spectrum of urban air pollution (Newton 1997). Technologies are available to measure 24-hour exposure of individuals to various criteria pollutants via body sensors as well as track where individuals spend their time (e.g. via GPS). Only by linking these two data streams can we begin to understand the air quality landscape of our human settlements. In the meantime, we do know that there are several 'environments' which convey risk to human health from prolonged exposure. These are buildings where smoking is permitted; buildings which contain asbestos; buildings with unflued gas heaters; mobile homes; new or renovated buildings; and buildings which harbour dust mites.
An increasing number of Australian buildings have undertaken tobacco smoke-free operation over the last 10 - 15 years, either voluntarily or in response to legislation. However, it is difficult to determine how many buildings are affected here since this information is seldom determined systematically. The Anti-Cancer Council of Victoria (1995) summarised organisations that became smoke-free as follows: Commonwealth Department of Health buildings (1986); all Commonwealth Public Service buildings (1988); Telecom, Australia Post, ICI, CSIRO, BHP, AMP, Westpac, 3M, Price Waterhouse, IBM, hospitals, state health departments, TAB betting offices in several states, Australian Army offices/halls/mess facilities (late 1980s to early 1990s); survey of New South Wales restaurants found less than 2% had total ban and 22% had a partial ban (1990); total ban in major fast-food chains Pizza Hut Australia, Hungry Jack's, Kentucky Fried Chicken and McDonald's (1992-1994). More recent restrictions include a total ban on smoking in indoor hospitality venues in the ACT (1994), SA and WA (1999), with restrictions likely in Victoria, NSW and Tasmania in 2000.
The Anti-Cancer Council of Victoria (1995) also summarised survey results from several states, and found that an increasing proportion of Australians are able to work in buildings with smoking prohibition. This information is most complete for Victoria, where nearly 90% of workers have been in workplaces with smoking prohibitions since 1992. The position in other States is less clear, and needs to be determined in terms of a national indicator.
Based on data obtained from the ABS Housing Survey of 1994, Ferrari et al. (1988) and Volkemer et al. ( 1995) among others, it is estimated that approximately 600 000 unflued gas heaters are in use in Australia, mostly in New South Wales, which represents 30% of all gas heaters. Note that the converse is that 70% of gas heaters are flued (i.e. the gas combustion products are vented outdoors and do not contaminate indoor air).
It has been found that mobile buildings such as caravans, mobile homes and mobile offices generally have high concentrations of formaldehyde which may exceed health-based exposure goals for occupants. This is considered to result from the high usage of wood-based panels and the low air infiltration rates encountered with such buildings (Brown 1997). The numbers of these residences, or the numbers of people residing in them, is considered an environmental indicator of this population's exposure to high levels of formaldehyde gas.
ABS census data for 1986, 1991 and 1996 indicates that in each period approximately 90 000 mobile residences have been occupied nationally, with no evidence that this number is changing over time. Nearly two-thirds of these are in Queensland and New South Wales, suggesting an influence of climate on these occupancies. The total number of occupants in the 1996 census was 161 400, or 0.9% of the population. While this is a small proportion of Australia's population, it still represents a substantial number of people potentially exposed to high levels of formaldehyde.
It has been found that building occupants are exposed to much higher levels of VOCs and formaldehyde in the first 6-12 months after construction or renovation of buildings, due to the large range of high-emission materials used in construction (e.g. paints, adhesives, sealants, carpets, wood-based panels, furniture). The health significance of these levels of exposure is an area of current research, with possible roles being considered for asthma, eye/nose/throat irritation, headache, nausea, lethargy, and general comfort and well-being (Brown et al. 1992, Brown 1999c).
New building construction is a common activity in Australia, and the number of new buildings constructed is considered an environmental indicator for occupant exposure to VOCs and formaldehyde, as presented in Table 54. The majority of new building construction is residential buildings where occupants will be located for large proportions of time. There were approximately 150 000 new buildings constructed per year throughout the 1990s. The number of people housed in these buildings is difficult to estimate because of the different types of dwellings, but would be expected to exceed 0.4 million. (The 1996 census recorded that 17.1 million people occupied 6.5 million dwellings.)
|Year||New houses||New other residential buildings||Alterations/additions||Conversions to residential buildings||Non-residential buildings||Total|
n.d. - no data available.
Source: ABS (1999h).
Australia experiences one of the highest incidences of asthma in the world, and the incidence continues to rise. It also has one of the highest levels of house dust mite allergen in indoor materials (bedding, furniture, carpets), and this allergen has been linked to asthma prevalence and severity in children. Generally, 80% of all asthmatics are allergic to dust mite allergen. The high level of the allergen in dwellings arises from the temperate climate along the coast where most of the population lives. Allergen avoidance by the population at large is highly desirable, though currently unachievable.
Research has shown that large numbers of occupants of commercial buildings experience detriment to their health and well-being due to poor indoor air quality, with significant national costs from health care and lost productivity (USEPA 1989, Fisk and Rosenfeld 1997). In recent years, a number of occupant surveys have been undertaken which have found levels of dissatisfaction ranging from 25 to 60% (Bakke et al. 1996, Christensen 1996, Sundell 1996). Studies in Australia have been limited in scope and application, but suggest that high levels of occupant dissatisfaction are common. For example, 62% of occupants of 228 low-rise offices in suburban Melbourne and 72% of occupants of 511 Commonwealth Government offices found the building air unacceptably 'stuffy' (Brown 1997).
Overseas research has demonstrated that poor indoor air quality results in very high costs to a nation, largely on the basis of health costs and lost productivity of workers. Estimates for Australia can be made based on the ratios of GDP here relative to those in countries where costs of poor indoor air quality have been estimated. Based on US figures, poor indoor air quality in Australia could incur a potential cost of several billion dollars per year (Brown 1997), but a detailed study of the incidence of health, well-being and sick building syndrome effects is needed for a more accurate estimate.
Environment Australia's Air Toxics Program has recently identified indoor air quality as a priority area. A State of Knowledge Report has been prepared, and Environment Australia is commissioning new research projects to improve air quality management in Australia (Environment Australia 2000).