Atmosphere

Air toxics and indoor air quality in Australia

State of knowledge report
Environment Australia, 2001
ISBN 0 6425 4739 4

Part B: Indoor air quality (continued)

Management of indoor air quality

8.1 Introduction

Ensuring that indoor air quality is of an acceptable standard presents a particular regulatory challenge not found with outdoor air. Indoor air quality is not only building-specific but may vary considerably within a particular building, according to the pollutant sources present and the rate of ventilation. Regulators or other bodies may set standards or goals for levels of various pollutants but how is compliance to be monitored? Ambient air quality can be monitored by a network of strategically located monitoring stations; but no such broad-scale monitoring is possible with indoor air. Indoor air quality needs to be monitored in individual buildings.

Any imposition of mandatory indoor air quality monitoring would be viewed by many people as unreasonably intrusive, particularly if private homes were to be included. Any program to monitor large numbers of individual buildings would also be extremely expensive. An alternative approach is to identify the sources of indoor air pollutants and other factors affecting indoor air quality and to make this information widely available. People can then make informed choices about matters affecting indoor air quality, at least in their homes. Individuals have limited ability to influence indoor air quality in public buildings such as schools, offices, hospitals and shopping malls, and a stronger case can be made for setting indoor air quality standards and/or guidelines for such buildings.

Regulation could be imposed at the level of the product or process, by setting emission standards or use protocols where a product or process is a significant source of harmful emissions. However, this approach does not address the effect of multiple minor sources of emissions.

8.2 Regulation of indoor air quality

No single government authority in any jurisdiction has responsibility for indoor air quality. Despite this, a range of responses related to indoor air in Australia are in place. These include State and Territory Government activities, the development of interim guidelines, changes to national ventilation codes, improved building design and community education. Gilbert and Black (2000) have summarised some of the responses of organisations to indoor air quality issues. They include the following.

8.2.1 Legal issues

No regulations or codes have been developed specifically for indoor air except in workplace environments. Despite this, there are legal obligations regarding indoor air quality on building designers, suppliers of materials and equipment, builders, building owners and tenants (BOMA 1994).

Liability issues associated with indoor air quality have been dealt with under common law and statute law in Australia (Gilbert and Black 2000). Under common law, building occupiers owe a duty of care to persons entering the premises and this may be seen to be breached if reasonable precautions (eg adherence to the Australian Standard for ventilation) are not taken (Immig et al 1997). The duty of care owed is greater to persons at greater risk (eg because of their greater susceptibility to an illness) or if the consequences of injury are greater.

The Department of Health and Aged Care’s review of indoor air quality (DHAC 2000) listed a number of Australian legal cases relating to illness from poor indoor air quality. The report also stated that the current indoor air quality policy vacuum might lead to greater legal action, following trends in the United States, creating the danger that policy becomes driven by litigation.

8.2.2 Regulation of indoor air in the workplace

Exposure of building occupants to pollutants in workplace air, whether industrial or nonindustrial, falls within the requirements of occupational health and safety legislation that is set at State level.

State occupational health and safety practices often draw upon guidance and standards developed by the NOHSC. The NOHSC declares national occupational exposure standards for substances. Exposure standards are guides to be used in the control of occupational health hazards. They are designed to assist regulatory agencies, occupational health and safety practitioners, employers, and employees and their representatives, and to secure workplace atmospheres that are as free as practicable from hazardous contaminants. Exposure standards have no legal status until incorporated in Commonwealth, State or Territory legislation. The exposure standards represent airborne concentrations of individual chemical substances that, according to current knowledge, should neither impair the health of nor cause undue discomfort to nearly all workers. They do not define safe and dangerous concentrations of chemicals and are not a measure of relative toxicity. They are not designed to apply to the control of community air pollution.

8.2.3 Regulation of indoor air quality in nonworkplace environments

In contrast to workplace and ambient air environments, there are no enforceable regulations specifically for nonworkplace indoor air environments. This situation is also common overseas. Regulating indoor air out of the workplace is difficult because:

However, performance-based regulations that impact on indoor air quality are enforced for some aspects of private dwellings. These often refer to standards (eg AS5601, AS1859) and codes (AG 601). A summary of standards and codes relevant to indoor air quality is presented in Appendix D.

8.3 Mechanical ventilation of buildings

Dilution ventilation is widely used to address building air quality by maintaining occupant comfort and controlling odours associated with human bioeffluents. Conventional heating, ventilation and airconditioning systems are designed as dilution or mixing ventilation systems. Conditioned air is supplied to occupied indoor spaces and mixes with room air. This provides a uniform temperature throughout the room and addresses other comfort requirements. Exhaust air is then returned to the airconditioning plant for recooling and mixing with approximately 10–30% fresh outdoor air to dilute polluted air from the building. In this way, pollutants are circulated through the building many times.

Ventilation above certain minimum standards is recognised as a central factor to the control of the great majority of the contaminants identified (EPA Victoria 1993), especially for mechanically ventilated buildings constructed in the 1980s and residential buildings constructed in recent years (Brown 1997). It acts by diluting the concentration of the contaminant and, as a part of the process of dilution, removes some of the contaminant to outdoor spaces.

The Building Code of Australia requires that all occupied rooms have ‘adequate flow-through or cross-ventilation and air quality’. This must be provided by natural ventilation from permanent, openable windows, doors or other devices with an aggregate openable size of not less than 5% of the floor area of the room to be ventilated, or a mechanical ventilation system conforming to AS1668.2-1991 and AS3666 (see Appendix D).

Standard AS1668.2-1991 sets minimum requirements for preventing an excess accumulation of airborne contaminants, or objectionable odours. These minima are based on needs to control body odour, food odour, air contaminants, or carbon dioxide concentrations. The current ventilation rate of 7.5 L/second/person was designed to maintain levels of indoor carbon dioxide exhaled by occupants below 1000 ppm. This carbon dioxide level is used as a surrogate for body odours unacceptable to 20% of visitors entering an occupied space. It is recognised that odours from other sources (eg environmental tobacco smoke) require greater ventilation rates.

AS1668.2-1991 does not prescribe other requirements associated with comfort, such as temperature, humidity, air movement or noise. The standard specifies the quality of outdoor air for use in ventilation of buildings, as presented in Table 8.1. If these levels are exceeded, the outdoor air must be treated to bring it within the required levels. Similarly, recycled air should not exceed these levels. AS1668.2 also includes requirements for natural ventilation of carparks.

Table 8.1: Recommended maximum accepted concentration of pollutants in outdoor air used in AS1668-1991
Pollutant Concentration (µg/m³) Organisation
Total suspended particles 90 (1 year)
260 (24 hours)
NHMRC
US EPA
Suspended matter 40 (1 year) WHO
Acid gases 60 (1 year) WHO
Sulfur dioxide 365 (24 hours)
60 (1 year)
US EPA
NHMRC
Sulfates 15 (1 year) NHMRC
Carbon monoxide 40000 (1 hour, max)
9900 (8 hour)
WHO/US EPA
WHO/US EPA
Nitrogen dioxide 340 (1 hour, max)
100 (1 year)
NHMRC
US EPA
Ozone 240 (1 hour, max) NHMRC/US EPA
Nonmethane hydrocarbons 160 (3 hours, max) US EPA
Lead 1.5 (90 days) NHMRC/US EPA

8.3.1 Indoor air quality and energy efficiency

There is a potential conflict between requirements for energy efficiency and satisfactory indoor air quality. The provision of fresh air through ventilation can be energy demanding because it may need temperature adjustment and cleaning and it requires distribution (Immig et al 1997). Since the ‘energy crisis’ in the 1970s, there has been a growing need for energy conservation in buildings. Consequently, there was a trend towards design and construction of ‘tight buildings’, with reduced rates of natural ventilation (ie ventilation rates with external doors and windows closed). As a result, indoor air contaminants could concentrate to much higher levels than otherwise expected. This was also true of buildings with mechanical ventilation, where ventilation rates were reduced to conserve energy. However, the detriment this caused to indoor air quality led to revision of current ventilation standards back to levels providing control of many occupant-related pollutants (Immig et al 1997).

AS 1668.2-1991 increased the minimum outdoor air ventilation rate from 2.5 to 7.5 L/second/person. However, an investigation of the ventilation systems of 228 low-rise office buildings in Melbourne found that 82% failed to meet the Australian Standard (Williams 1992 in Brown 1997).

EPA Victoria found that:

In agreement with the building sector, the Federal Government has resolved to eliminate the worst energy-performance practices through a national standard approach to minimum performance requirements for buildings. This approach aims to reduce greenhouse gas emissions from buildings. The Building Code of Australia is seen as the most appropriate place for minimum energy requirements of new buildings and major refurbishments. Following studies by the CSIRO Division of Building Construction and Engineering, the Australian Greenhouse Office has released a scoping study for incorporating minimum energy performance into the Building Code of Australia.

8.3.2 Relationship between ventilation and indoor air quality

There has been an assumption that building-related health complaints are primarily caused by inadequate ventilation; for example, this was the case in over half the buildings investigated in NIOSH health hazard evaluations. Whether poor ventilation was the prime cause of the complaints and whether increased ventilation could remedy this was not determined.

Studies of ventilation rates and contaminant concentrations have shown mixed results (see Table 8.2).

Table 8.2: The effect of ventilation rates on indoor pollutants
  Nagda et al (1991) Collett et al (1991) Palonen and Seppanen(1990) Farrant et al (1990) Baldwin and Farrant (1990) Menzies et al (1993)
Formaldehyde No effects No effects No effects Significant   Significant
Nicotine No effects No effects        
Total VOCs No effects   No effectsa Significant Significant Significanta
Carbon dioxide Margina No effects No effects Significant   Significant
Carbon monoxide Marginal          
Particles   No effects No effects      
Concentration of microbes   No effects No effectsb      
Radon     No effects      
NOx     Significant      

Notes:
aVOCs.
b Bacteria and mould.
VOC = volatile organic compound.
NOx = oxides of nitrogen.

Godish and Spengler (1996) found the relationship between ventilation rates, building-related health complaints, occupant dissatisfaction with indoor air quality and levels of indoor contaminants to be complex. The study listed the following factors likely to have a confounding effect on research into relationships between ventilation rates and sick building symptoms:

The study concluded that, despite widely held beliefs to the contrary, there is little evidence to support a relationship between sick building symptoms and mechanically ventilated buildings per se. However, evidence was found to implicate buildings with airconditioning and cooling with higher rates of symptoms, suggesting that these systems are a significant risk factor for sick building complaints.

8.3.3 Development of improved ventilation mechanisms

A new building ventilation system has emerged from Scandinavian countries. The technique, called displacement ventilation, provides energy-efficient cooling and improved ventilation of the building. Displacement ventilation introduces cool, fresh air at low velocity at floor level. The cool fresh air warms and rises without mixing with the stale air, and pushes room pollutants upward to be exhausted to the atmosphere. This greatly improves fresh air ventilation because all supply air is fresh and mixing with return air is avoided. Cooling energy consumption is reduced because the heat generated in the building is exhausted to the atmosphere. Displacement ventilation also eliminates return air ducting and fans, thus reducing installation costs.

Displacement ventilation is particularly effective in tall building spaces; in buildings with low ceiling heights, cool draft problems can be encountered. In addition, the technique can be used only for cooling and it may not satisfactorily cool buildings with high internal heat loads.

One response to the need to minimise energy use while maintaining adequate indoor air quality has been the emergence of mixed mode (mechanical and natural) systems. Some of these systems use the building’s thermal mass, combined with stack-assisted ventilation, to provide adequate flows of fresh air and to control internal temperatures (Willis 1999). Windows that can open to increase natural ventilation and allow greater occupant control are also increasing in number.

8.3.4 Airconditioning filtration

Airconditioning filtration is generally inadequate for the removal of particles from indoor spaces. Heating, ventilation and airconditioning systems using standard media filters have been found to reduce particle concentration by only 40% (Morawska 2000). Mathieson (1998) has listed the following examples of technological solutions for improved filtration of the indoor air pollutants:

8.4 Reduction of indoor sources

Many indoor air pollutants have clearly identifiable sources. It is now widely accepted overseas that the control of emissions is the most important strategy for achieving improved indoor air quality. In Australia, Brown (1992), Gilbert (1993) and NHMRC (1993) have recommended this approach.

ANZEC (1990) found a need for concerted and coordinated action by all levels of government and associated bodies to ensure that air quality in Australian indoor environments is improved in a planned and cost-effective manner. ANZEC’s suggested options for consideration included:

Immig et al (1997) have outlined selection criteria for an extensive range of building and furnishing materials to limit sources of indoor air pollutants; these include general criteria, as well as specific criteria for surface finishes, sealants, adhesives, insulation, plywood and wood panels, floor coverings, furniture and appliances.

Table 8.3 outlines some measures that can be used to reduce the potential sources of indoor pollutants.

Table 8.3: Measures that can be used to reduce the potential sources of pollutants indoors
Source of emissions Measure to reduce potential emissions
Flooring No carpet, occasional rug, precoated flooring to avoid need for lacquer finishes
Paints/coatings Inside painted with low-emission, high-quality acrylic coatings; odourless clear finishes on skirting and stairs
Furniture Old and new furniture, mostly solid timber or fully laminated particleboard
Heating/cooking Natural gas, gas stove (rangehood, should vent to outside), electric oven, gas heater (with flue to outdoors)
Ventilation Measures to ensure an acceptable minimum ventilation level (eg external wall vents)

Source: Adapted from Brown (1999) and Brown (2000).

8.4.1 Australian initiatives

Voluntary initiatives by industry have been undertaken for formaldehyde emission from pressed-wood products for several years. Improvements in manufacturing and resin technologies, particularly the use of lignin-based adhesives, mean that most particleboard and medium-density fibreboard made in Australia now meet test criteria that enable them to be sold as ‘low-formaldehyde emission’ products. The test criteria require that the emission of formaldehyde from finished products that contain formaldehyde be less than 1 ppm. Even in newly constructed mobile homes and offices, the use of low formaldehyde emission products should ensure that indoor air concentrations of formaldehyde from this building material source do not exceed 50 ppb (Douglas 1998).

AS/NZS 1859.1:1997 (Reconstituted wood-based panels – Particleboard) and AS/NZS 1859.2:1997 (Reconstituted wood-based panels–Medium density fibreboard) include formaldehyde emission limits for pressed-wood products However, these standards may not control formaldehyde emissions adequately as they describe measurement methodologies that have limitations, and they apply only to a limited product range (S Brown, pers comm, 2000).

Voluntary initiatives by the gas industry have reduced nitrogen dioxide emissions from new unflued gas heaters. In January 1991, the AGA set nitrogen dioxide emission rate limits for flueless gas heaters to 5 ng/J or below (the limit was formerly 15–30 ng/J). For stoves, this figure is currently 15 ng/J. These limits have been set with the aim of preventing indoor nitrogen dioxide concentrations above 300 ppb, a design level set by AGA (Campbell and Saxby 1994).

In 1990, the New South Wales Department of School Education instituted an ongoing program to rectify gas leaks and replace unflued gas heaters with heaters that emitted low levels of oxides of nitrogen. This has reduced indoor oxides of nitrogen concentrations considerably. However, large numbers of unflued gas heaters are still used in other buildings throughout Australia. Ferrari (1991) has recommended that the use of unflued combustion heaters and cookers be discouraged, in favour of flued heaters, heaters that emit only low levels of oxides of nitrogen, and externally vented cookers.

8.4.2 Overseas initiatives

Source emission limits to prevent total VOC concentrations above 500 µg/m per source or ozone concentrations above 20 µg/m have been described for the United States (Tucker 1990). These are presented in Table 8.4 below.

Table 8.4: Recommended emission limits for low-emitting materials and products for commercial buildings
Material or product Maximum emission
Floor materials or coatings 600 µg TVOC/m² /hour
Wall materials or coatings 400 µg TVOC/m² /hour
Moveable partitions 400 µg TVOC/m² /hour
Office furniture 2500 µg TVOC/hour/workstation
Office machines (central) 250 µg TVOC/hour/m³ of space; 10 µg ozone/hour/m³ of space
Office machines (personal 2500 µg TVOC/hour/m³ of space; 100 µg ozone/hour/m³ of space

Note: TVOC = total volatile organic compound

Source: Tucker (1990).

State of Washington (United States) established criteria for pollutant emissions from manufactured products, interior materials and other pollutant sources in commercial buildings (Black 1993). The emission criteria were designed to ensure that after 30 days building air concentrations did not exceed the following limits for the listed pollutants:

The total VOC requirement was considered a ‘generalised’ VOC control mechanism. There were additional requirements for the emission rates and predicted building concentrations to be reported for compounds listed as carcinogens or teratogens, predicted to exceed one-tenth of occupational exposure standards, or listed as primary or secondary pollutants in National Ambient Air Quality Standards.

The majority of United States carpet manufacturers periodically submit product samples for the determination of total VOC, styrene, 4-phenylcyclohexene and formaldehyde emission rates as part of a voluntary program under the Carpet and Rug Institute (US EPA Carpet Policy Dialogue Group 1991). Manufacturers are able to attach a certified ‘green label’ to their product if emission rates are below specified limits.

A Commission of European Communities program develops procedures for evaluating pollutant emissions from building materials (McLaughlin and Knoppel 1994). This work is well advanced with regard to formaldehyde emission from pressed-wood products; it is currently focusing on procedures for evaluating VOC emissions.

In Germany, according to Cutter Information Corporation (1992b), several regulations aim to prevent exposure to carcinogenic VOCs from building materials through the development of product emission goals and the imposition of bans on the:

8.4.3 Improved building design

Architects and building managers play vital roles in determining the level of indoor air quality achievable. If indoor air quality issues are identified at the outset of a building program, the chances of creating an optimal internal environment are high.

The Inquiry into Urban Air Pollution in Australia concluded (AATSE 1997) that guidance to the individuals responsible for the design, construction, and maintenance of buildings is clearly required. Building professionals need to be made more aware of building-related illnesses, and so do the wider community, possibly through education programs.

One direct effect of building design is whether the building uses natural or mechanical ventilation (Immig et al 1997). Fundamental aspects of the building, including its location, depth and placement with respect to prevailing winds, determine the feasibility of natural ventilation.

The specification of construction materials and methods during building design also affects indoor air quality through the out-gassing of toxic pollutants from the interior materials and, to a lesser extent, from the building’s structure and envelope. As stated above, relevant standards with emission limits applying to building materials are the AS/NZS 1859 series for reconstituted wood-based panels, which is referenced in the Building Code of Australia. This standard includes clauses covering formaldehyde emissions associated with urea-formaldehyde foam thermal insulation (Immig et al 1997).

Thomson (1998) has argued that building specifications do not place enough emphasis on indoor air quality. Instead, they focus on prompt construction processes and cost-effective materials; indoor workplace health and safety guidelines are referenced only when required to meet the compliance standards of building authorities.

In Australia, each level of government has significant but different responsibilities for the regulation of building and construction. For example, responsibility for the selection, planning and design of urban developments often comes under the jurisdiction of local governments.

Regulation of the building industry occurs primarily at the State and local level and through the Building Code of Australia, but Australian governments can use other mechanisms to effect environmental change. These include developing partnerships with industry. As stated above, the Australian Greenhouse Office has released a scoping paper examining the incorporation of minimum energy requirements into the Building Code of Australia. Governments can also provide strategic, administrative and financial support to improve the environmental performance of buildings and remove perverse incentives that discourage investment in the development of ‘greener’ buildings.

The materials that form the fabric of building are subjected to some degree of safety testing, but these are limited and do not cover all risks (Ball 2000). Several activities in recent years have been directed to specifying aspects of the design of buildings so as to minimise indoor air quality problems in the future. An example of this type of activity in Australia includes the EPA Victoria proposed ‘ideal house’ (see Section 9.2).

Various regulatory requirements are imposed by government agencies, but statutory obligations are generally based on occupational exposure. For example, workplace health and safety legislation places a duty of care or statutory obligations on employees, subcontractors, people in control of workplaces, designers and workers.

As a result of problems with seamless flooring products in a Far North Queensland school, a new generation of performance-based specification, which requires industries to understand the potential impacts of their products, has been developed (Ball 2000). Lessons learned included that industry should be involved and that industries such as the seamless flooring industry need to take responsibility for self-regulation and set industry standards to reduce health risks.

8.5 Management approaches to environmental tobacco smoke

Australia has been active in implementing tobacco control strategies and first formalised its commitment to a comprehensive approach to tobacco control in the 1991 National Health Policy on Tobacco in Australia. Tobacco smoking, however, remains the single largest preventable cause of premature death and disease in Australia.

Since the 1970s, as more information has come to light about the toxic nature of environmental tobacco smoke, increased attention has been paid to the association between environmental tobacco smoke exposure and a range of detrimental health effects. These effects include those arising from both short-term and long-term exposures. The NHMRC reviewed Australian and international scientific evidence concerning the possible health effects of exposure to environmental tobacco smoke in 1986 and in 1997. The 1997 review conservatively concluded that exposure to environmental tobacco smoke causes lung cancer in adults and lower respiratory illness in children, contributes to the symptoms of asthma in children and may also cause coronary heart disease in adults (NHMRC 1997).

In 1998, the Australian Health Ministers Advisory Council agreed that passive smoking be included in the work program of the Legislation Reform Working Party and that a national response to the issue of passive smoking be prepared. The response, which will be completed in 2001, comprises a package of material to assist jurisdictions in developing appropriate legislation. Australia has responded to the mounting evidence of dangers imposed by environmental tobacco smoke over the last decade primarily by encouraging formal and informal industry self-regulation of smoking in enclosed public places and workplaces.

More formal arrangements include the prohibition of smoking in all federally owned and operated buildings and on all forms of public transport. In 1988, a smoke-free environment policy was adopted throughout the Australian Public Service and Commonwealth controlled buildings. This policy was implemented through nonbinding guidelines issued by the Public Service Board. Since 1991, the Commonwealth has decided that it has a general duty of care, under the Occupational Health and Safety (Commonwealth Employment) Act 1991, to protect the health and safety of employees at work. This may include providing a smoke-free workplace. In July 1992, smoking was banned in all airport buildings (passenger terminals and offices) operated by the Federal Airports Corporation.

From 1 December 1987, the Commonwealth Government prohibited smoking on domestic airline flights and commuter services. This ban was extended on 1 October 1990 to include the domestic leg of all international flights. Smoking was banned on buses and coaches registered under the Federal Interstate Registration Scheme from 1 July 1988.

The ACT, South Australia and Western Australia have legislated for smoke-free indoor areas in workplaces and other public places such as restaurants and cafes. Most jurisdictions have also undertaken various forms of education, information and assistance programs, and campaigns, with the aim of increasing nonsmoking provision in restaurants, cafes and other enclosed public places. The threat of litigation has also been influential in the development of these public health initiatives.

During the last decade, progress has been made in extending smoke-free facilities, but one in five workers nationally have no restrictions on smoking in their place of work (Makkai and McAllister 1998), and effective nonsmoking dining in cafes and restaurants is not currently the norm. It appears likely that the systematic provision of smoke-free workplaces and enclosed public places will not be achieved by relying on education, information, common courtesy, voluntary codes and other forms of self-regulation. New South Wales and Western Australian taskforces on passive smoking both concluded that legislation would be the most effective strategy for significantly reducing exposure to environmental tobacco smoke in enclosed public places and workplaces.

In entering the next century and in line with calls from the World Health Assembly for the implementation of comprehensive tobacco control strategies, Australia has reaffirmed and formalised its comprehensive approach to tobacco control and ensured a firm commitment to future tobacco control initiatives. As part of this commitment, Australia is participating in the development of the WHO’s Framework Convention on Tobacco Control. The National Tobacco Strategy 1999 to 2002–03 recognises that future successful action in tobacco control hinges upon coordinated and comprehensive national action. The strategy is intended to expand on the range of initiatives already implemented by Commonwealth, State and Territory Governments and NGOs and will link with other relevant national strategic documents to ensure an integrated approach.

An overarching goal and four objectives are identified for the strategy. In order to meet the goal and overall objectives and expand on the initiatives already undertaken by the Commonwealth, State and Territory Governments and nongovernment agencies, six key strategy areas are identified. Each of these areas has its own objectives, which, if achieved, will contribute to meeting the strategy’s overall objectives and goal. Actions and strategies to achieve the key strategy area objectives are recommended. ‘Key Strategy Area 6: Reducing Exposure to ETS’ is a vital part of the strategy and of direct relevance to indoor air quality. Its objectives are:

8.6 Future management options

A recent report produced by the Queensland Department of Public Works for the Commonwealth Department of Health and Aged Care has reviewed indoor air quality (DHAC 2000). The report argues that the knowledge on indoor air quality is sufficient in many areas to identify pollutant sources, health outcomes and some dose–response relationships, and to take policy directions.

Currently there is no central focus for indoor air quality in Australia for a systematic response and no single body responsible for it in any jurisdiction. The measurement of indoor air quality and the assessment of human health impacts have been fragmented, a situation that will continue until a single body coordinates responsibility for management of indoor air quality.

The harmonisation of public health, occupational and indoor air quality standards is important to ensure consistency, cost-effectiveness and efficiency, and the shared use of technical and other solutions (Morawska and Moore 2000).

The inclusion of indoor air issues in the Air Toxics Program was welcomed broadly by key stakeholders at the Air Toxics Forum. The forum’s support was consistent with community submissions received during the development of the Ambient Air Quality NEPM where it was argued that the scope of that NEPM was too narrow because it did not include standards for indoor air quality.

The Commonwealth Department of Health and Aged Care's review of indoor air quality (DHAC 2000) discussed some of the advantages of addressing indoor air quality through a NEPM. It stated that this approach would build upon existing legislative infrastructure and provide an impetus to address indoor air quality issues. However, it should be noted that section 14(1) of the NEPC Act 1994 currently restricts governments to only making air quality related NEPMs that address ambient exposure. As drafted currently, the Act does not allow a NEPM on indoor air quality.

Actions addressing source control will need to be central to future initiatives. Responses could be embodied within any combination of voluntary industry agreements, codes, standards and guidelines. Specific actions may include the development and adoption of techniques to produce low-emission building materials, with standardised tests to verify that products meet emission guidelines or limits. The provision of more information and labelling to enable consumers to choose ‘green’ or low-emitting substances would complement these initiatives and stimulate further development of those products.

Future challenges for the building sector (architects, engineers, urban planners, builders, etc) include the incorporation of indoor air quality concerns into building design, construction and maintenance, possibly through better engagement of health professionals.

Targeted public education programs, based on scientific research, are an important tool for improving indoor air quality, especially in homes. These could include general programs to raise awareness. General programs would need to communicate risk to targeted ‘at risk’ populations to encourage action to reduce risk without inflaming the situation (Morawska and Moore 2000). Other programs could address specific issues, for example techniques for reducing house dust mite populations. Immig et al (1997) recommended strategies to educate building occupants, including building managers, to increase the awareness of the importance of maintaining good indoor air quality. This includes knowledge of the proper operation of ventilation systems.

Key

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