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Environment Australia, June 2002
ISBN 0 6425 4738 6
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The State of Knowledge Report: Air Toxics and Indoor Air Quality in Australia was developed with significant input from other Commonwealth agencies, the environment agencies of the States and Territories, technical experts, non-government organisations (including industry and environment sectors) and through public consultation. The State of Knowledge Report addresses the wide range of issues relevant to air toxics. It is a resource for scientists, policy makers and the community to help them understand more about air toxics and indoor air quality.
The State of Knowledge Report builds on work undertaken by the Environment Protection Authority (EPA) Victoria on behalf of the Australian and New Zealand Environment and Conservation Council (ANZECC). In 1999, the EPA Victoria conducted an extensive review of studies conducted on air toxics in Australia and New Zealand.
Full copies of the EPA Victoria report Hazardous Air Pollutants-A Review of Studies Performed in Australia and New Zealand June 1999, Volumes 1 and 2 (publication numbers 650 and 651 respectively) can be ordered by calling (03) 9695 2722.
Priority air pollutants
An important feature of the ANZECC review was that it emphasised the need to identify a smaller number of key air toxics for further study. There are so many different compounds classified as air toxics that it is not feasible to monitor them all.
A list of priority air toxics was identified for the Air Toxics Program in consultation with the Technical Advisory Group and the Steering Group. The selection of the priority air toxics was based on a number of previous significant studies including the ranking system in the National Pollutant Inventory (NPI) and the system developed by EPA Victoria in the ANZECC review.
In developing the priority list of air toxics, it was recognised that a number of these pollutants would have significant impacts on indoor air quality (for example formaldehyde and the VOCs). In addition, four criteria pollutants were identified for consideration in the indoor context: carbon monoxide, lead and lead compounds, oxides of nitrogen, and respirable particulate matter.
Priority Air Toxics identified under the Living Cities-Air Toxics Program
| Acetaldehyde | Methylenebis(phenylisocyanate) (MDI) |
| Acrolein | Nickel and compounds |
| Acrylonitrile | Polycyclic aromatic hydrocarbons (PAHs) |
| Arsenic and compounds | Polychlorinated biphenyls (PCBs) |
| Benzene | Phthalates |
| 1,3-Butadiene | Polychlorinated dioxins and furans |
| Cadmium and compounds | Styrene |
| Chromium (VI) compounds | Tetrachloroethylene |
| Dichloromethane | Toluene |
| Fluoride compounds | Toluene-2,4-diisocyanate |
| Formaldehyde | Total Volatile Organic Compounds* |
| Mercury and compounds | Trichloroethylene |
| Methyl ethyl ketone | Vinyl chloride (monomer) |
| Methyl isobutyl ketone | Xylenes |
* Total Volatile Organic Compounds (or Total VOCs) is a term used to measure and report on the concentration of all VOCs present in a given sample. (VOCs are defined on page 20.) The list of priority air toxics also includes individual VOCs, namely acrolein, acrylonitrile, benzene, methyl ethyl ketone, styrene, tetrachloroethylene, toluene, toluene-2,4-diisocyanate, trichloroethylene and xylenes.
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The National Pollutant Inventory or NPI is Australia's national database of pollutant emissions from both industrial and non-industrial sources. It provides some information about estimated emissions of air toxics in Australia. Most of the priority air toxics are included on the NPI's database. The NPI database can be viewed at www.npi.gov.au |
In compiling the State of Knowledge Report, information was brought together on Australian research and case studies of air toxics and indoor air. This highlighted not only the extent of work undertaken to date but also the gaps in knowledge.
The following studies (Table 2) were commissioned under the Living Cities- Air Toxics Program. These studies have been designed to help fill some important knowledge gaps and provide input to the development of national strategies for managing air toxics and indoor air quality.
Four of these studies have been completed and are published as a series of technical reports available at www.ea.gov.au/atmosphere/airtoxics/. The titles of these publications are:
Technical Report No. 1: Toxic Emissions from Diesel Vehicles in Australia
Technical Report No. 2: Polycyclic Aromatic Hydrocarbons (PAHs) in Ambient Air in Australia
Technical Report No. 3: Review of Data on Heavy Metals in Ambient Air in Australia
Technical Report No. 4: Review of Literature on Residential Firewood Use, Wood-Smoke and Air Toxics
Technical Report No. 5: Emissions from Domestic Solid Fuel Burning Appliances
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Health studies Environment Australia commissioned the Department of Environmental Protection of Western Australia to undertake a desktop review and to develop a database of air toxics related health studies in Australia. The results of this study appear in the State of Knowledge Report. The review has highlighted the lack of information on the potential exposure of the Australian population to air toxics in ambient air and the need for more research into air toxics in the interests of public health. |
Table 2 - Major Projects under the Air Toxics Program
| Title | Type of study |
|---|---|
| Polycyclic Aromatic Hydrocarbon (PAH) concentrations in Australia | Desktop study to review ambient PAH levels in Australia. |
| Toxic Emissions from Diesel Vehicles | Tests of toxic emissions from a range of current technology diesel vehicles: 1. run on standard commercial diesel fuel; 2. run on different fuels, allowing for a comparative study of emissions. |
| BTEX Personal Exposure Monitoring | A four-city study (Sydney, Melbourne, Perth and Adelaide) to determine the significance of sources of BTEX (benzene, ethylbenzene, toluene and xylenes) and contribution those sources make to human exposure. |
| Determination of Emission Factors from In-Service Vehicles | Testing to determine the emission factors for a variety of pollutants from in-service vehicles. |
| Emissions from Domestic Solid Fuel Burning Appliances | Identification of emissions from domestic solid fuel burning appliances (open fire places, older and new slow combustion heaters) using a variety of fuelwood types (hardwood, softwood, different moisture content) and operating conditions (maximum and minimum air flow). |
| Review of Data on Heavy Metals in Ambient Air in Australia | Desktop study involving the analysis of existing data, including raw monitoring data collected by the Queensland Environmental Protection Agency. |
| Study of Particle Composition | Determine the chemical composition and seasonal variation of fine particles in Melbourne, Sydney, Brisbane and Adelaide. Compare the result with epidemiological data to identify the toxic components responsible for observed health effects. |
| Indoor Air Quality in Australian Commercial Buildings | Desktop study to review, reconcile and consolidate existing data on the level of air pollutants in commercial buildings in Australia. |
Fifty volunteers in Adelaide, Sydney, Melbourne and Perth are participating in a study to measure personal exposure to four air toxics-benzene, toluene, ethylbenzene and xylenes (BTEX). The 200 participants will wear a small gas-monitoring device for two five-day periods in both winter and summer. Analysis of the contents of the devices will show participants' exposure to the four air toxics in their normal daily activities.
This is the first major study of its kind in Australia. The results of the project will be used to develop targeted management strategies to help reduce population exposure to these air toxics and in development of the Air Toxics NEPM. Included in the study is monitoring of selected sources which may contribute to BTEX exposure.
The study is being coordinated by the Western Australia Department of Environmental Protection and is a major collaborative effort involving environment agencies in New South Wales, Victoria, Western Australia and South Australia with New South Wales Health. Other organisations involved are CSIRO, the University of Western Australia, Flinders, Monash and Murdoch Universities.
Results from the winter monitoring indicate that the average exposure to BTEX is relatively low. Preliminary analysis of the exposure/activity data shows there appears to be an increase in BTEX exposures associated with the refueling of motor vehicles. The final report is to be released in late 2002.
Air toxics may be present in the gaseous or the particulate phase. The individual pollutants that make up the priority list are largely drawn from the following broad classes of compounds:
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In the broader sense, some pesticides could fall within the definition of air toxics. However, pesticides are subject to national management under the National Registration Authority (NRA) for agriculture and veterinary chemicals. The Authority works in partnership with agencies responsible for agriculture, environment, health and occupational use to manage the registration and use of pesticides. For further information on NRA see web link nra.gov.au |
Metals and metal compounds
Although some metals and their compounds are essential to humans and other animals as part of a healthy diet, they can be toxic at high concentrations. Other metals, particularly heavy metals (such as arsenic, cadmium, lead and mercury), can be toxic at relatively low concentrations. All metals occur naturally, and they are released in to the air through windblown dust or volcanic activity. However, human activities such as mining and combustion can also increase the concentration of metals in air.
Polycyclic aromatic hydrocarbons (PAHs)
Polycyclic aromatic hydrocarbons (PAHs) are a class of complex compounds that can exist as vapours or solids, depending on the size of their molecules. They are often released when organic matter such as wood or coal is not fully burnt. Major sources of these substances include wood-burning heaters, motor vehicle exhaust (particularly diesel exhaust), cigarette smoke, laying asphalt roads, and industrial processes including coke making. PAHs are widespread pollutants of the environment and a number of them are either known or suspected to cause cancer.
Volatile organic compounds (VOCs)
Volatile organic compounds (VOCs) are chemicals that contain carbon and easily form vapours at normal temperature and pressure. They comprise a very large and diverse group of compounds. Some of the more commonly known VOCs are benzene and toluene. VOCs come from burning fuels such as petrol, oil, wood, coal and natural gas. They are also found in solvents, paints and glues. Short-term exposure to high levels or long-term exposure to low levels of some of these compounds may cause health problems. These compounds can affect the environment, contributing to the formation of ozone and smog.
Persistent organic pollutants (POPs), including dioxins and furans2
Persistent organic pollutants (POPs) are hazardous substances that can stay in the environment for a long time. They can move between countries through the oceans or air, and because of this they are known as transboundary pollutants.
Dioxins are just one type of POP. POPs are highly toxic and unwanted by-products of many industrial chemical processes and combustion. In Australia, dioxins and furans are emitted from natural sources and from some human activities. Bush fires are a key natural source. Human activities that produce dioxins include residential wood fires, coal and oil combustion, metal production, medical waste incineration and cement production.
Dioxins are fat-soluble compounds. They are primarily transported through the air and enter the food chain when animals eat contaminated plants. Humans are exposed to dioxins mainly through consuming contaminated foods that contain fat. These can include foods such as meat and meat products, chicken, dairy foods, fish, eggs and breast milk.
Although breast milk is cited as a source of dioxins, it is only one amongst many. Health authorities, including the World Health Organization, the Commonwealth Department of Health and Ageing and the National Health and Medical Research Council(NHMRC), agree that breast milk remains undoubtedly the optimal source of nutrition for infants. In the absence of information about dioxin levels across the whole spectrum of foods in Australia, including the levels in infant formula, breast milk remains the most important and appropriate food for infants.
Air toxics are sometimes released from natural sources such as bushfires, but most emissions come from human activities. Industry is a major source of air toxics, but it is important to know that some everyday human activities also produce emissions of air toxics.
An often overlooked source of air pollution is lawnmowers. Two and fourstroke petrol engine lawnmowers do not have any pollution control technology such as catalytic converters. As a result, they can contribute significantly to levels of pollution in the local area. The amount and type of pollution emitted depend on the type of mower and the fuel used.
Hints
Chemicals emitted when mowing the lawn include:
Paints and thinners are sources of air toxics, and most people will have noticed the strong smell given off by these substances. VOCs are the main emissions from paints and from the solvents used as thinners or for cleaning up after painting.
Particular care is needed when preparing a surface for repainting. In the past, paint containing lead was used in many Australian homes. Although homes built before 1970 are most at risk, some houses built more recently may also have paint containing lead. This means there is a risk of releasing lead and air toxics into the air if the original paint is disturbed using dispersive methods such as heat-gunning and dry-sanding.
Hints
Chemicals emitted when using paints and thinners include:
The family car is a well-recognised source of air pollution. Motor vehicles produce air toxics from fuel combustion and evaporation. The amount of air pollution a car gives out during its use depends on the type and age of the vehicle, whether or not it is well maintained, the type and composition of the fuel and the traffic flow. Generally, improvements in vehicle design have led to increased efficiency and resulted in reduced emissions.
In a full life-cycle analysis, emissions from the manufacture and final disposal of the vehicle would also be considered.
Petrol produces more air toxics through evaporation than diesel. The main air toxics from petrol are VOCs. Diesel vehicles produce a complex mixture of air pollutants, mainly composed of gaseous and solid material. The mixture consists of small particles, including carbon particles, nitrogen oxides, carbon dioxide, PAHs, VOCs, and metals.
The Commonwealth Government introduced national fuel quality standards for petrol and diesel which regulate the supply of fuel to consumers, reduce toxic vehicle emissions and ensure that by using clean fuels, modern vehicles fitted with advanced emission control technologies operate at peak performance. The standards, which came into effect from 1 January 2002, prohibit lead in petrol.
New design rules coming into effect from 2003-04 will set stringent standards for emissions from new petrol and diesel vehicles. They will progressively bring Australian vehicle standards into line with those in Europe.
As the number of diesel vehicles increases, so does their contribution to total air pollution. By 2015, the proportion of diesel vehicles on Australian roads will have grown from about eight per cent to 15 per cent and diesel vehicle travel will increase by 146 per cent.
On 29 June 2001, the National Environment Protection Council adopted the National Environment Protection (Diesel Vehicle Emissions) Measure. This introduces emission standards for diesel vehicles already on the road as well as strategies for meeting those standards. These requirements are in addition to the tighter emission standards for new diesel vehicles and improved quality of diesel fuel.
Hints
Chemicals emitted when driving a vehicle include:
Choose the most efficient, lowest-polluting model of vehicle:
Further information about the Fuel Consumption Label and copies of the Fuel Consumption Guide can be obtained by calling the Australian Greenhouse Office Infoline on 1300 130 606.
Another well-known source of air pollution is environmental tobacco smoke, which is made up of mainstream and sidestream smoke. Mainstream smoke is the smoke that a smoker inhales and exhales. Sidestream smoke is smoke produced by smouldering tobacco in a pipe, cigar or cigarette between puffs or that passes through the cigarette paper during puffing. Because sidestream smoke comes from tobacco that is smouldering rather than burning, it contains higher amounts of some toxic and carcinogenic agents than mainstream smoke.
Chemicals emitted when smoking cigarettes include:
Regulating environmental tobacco smoke
Control of tobacco smoke is a good example of how regulation can improve indoor air quality. Smoking has been prohibited in all federally owned and operated buildings and on all forms of public transport since 1988, on domestic flights and commuter services since 1987, on the domestic portion of international flights since 1990 and in all airport buildings since 1992. In some parts of Australia, public places such as restaurants and cafes are smoke-free, and most States and Territories have undertaken education programs and campaigns to increase non-smoking areas in enclosed public places.
In spite of the moves to regulate tobacco smoke in public places, currently there are no restrictions on smoking in the workplace for one in five workers. This is likely to improve in the future, as Australia is participating in the World Health Organization's Framework Convention on Tobacco Control. This initiative includes the establishment of smokefree environments as the norm and aims to increase public awareness and understanding of the risks of exposure to environmental tobacco smoke.
For assistance with giving up smoking, phone Quitline on 13 18 48 for the cost of a local call.
Australia has a long history of using wood as a source of heat in colder weather. Wood burning has become a major source of air pollution in many urban areas in the winter months.
There is a large variety of wood heater types from open fireplaces, fireplace inserts to a range of controlled combustion wood heaters. Of these, open fireplaces are the least efficient and release the highest levels of air toxics into the house.
Many people may be unaware that the emissions from home wood heaters include air toxics. Air toxics emitted may include dioxins, PAHs and various VOCs. The amount of air toxics produced depends on the type of heater, the type of wood and how the heater is used.
An Australian Standard for particle emissions from heaters was released in 1992 and has recently been strengthened, setting a maximum of four grams of particle emissions from one kilogram of wood burnt. When used properly with appropriate wood, wood heaters that comply with the new standard give off significantly less carbon monoxide, small particles and VOCs than older heaters that do not meet the current Australian Standard.
For more information phone Freecall 1800 065 823 or visit www.ea.gov.au/woodsmoke.html
Hints
What to do to reduce smoke from wood burning:
Chemicals emitted when burning wood include:
In cold weather:
The National Health and Medical Research Council (NHMRC) defines indoor air as any nonindustrial indoor space where a person spends a period of an hour or more in any day. This can include the office, classroom, motor vehicle, shopping centre, hospital and home.
Australians spend 90 per cent or more of their time indoors, so it is important to ensure that the quality of indoor air is sufficient to protect health and wellbeing. Poor indoor air quality is generally accepted to be a cause of health problems. Recent studies in the United States suggest that indoor air pollution is among the top five environmental risks to public health.
The quality of indoor air is influenced by two main factors-the amount and composition of outdoor air getting in and the emissions from indoor sources. This means that pollutants can be generated within the indoor environment and they can also be transferred from the outdoor air (from motor vehicle emissions, for example).
Despite the long periods Australians spend indoors, relatively little research has been done specifically on the effects of indoor air on our health.
The main pollutants of indoor air in Australia
Many air pollutants can be found in the indoor environment-for example, criteria pollutants, air toxics and biological contaminants.
Sources of indoor pollutants include emissions resulting from the use of cookers, wood heaters and unflued gas heaters and VOCs from cleaning materials, furniture and paints. Of the six criteria pollutants, carbon monoxide, nitrogen dioxide, lead and particles can adversely affect the quality of indoor air.
Indoor air includes the air inside vehicles such as cars and buses where passengers spend an hour or more a day. As Australians spend more and more time travelling it is important that they consider the quality of the air inside vehicles.
In-cabin concentrations of air pollutants are influenced by levels in both the indoor and outdoor air. The air pollution accumulating in the interior of cars consists of petrol and diesel exhaust and any environmental tobacco smoke produced by a smoking passenger. In addition, the interior finishes make a significant contribution to in-cabin pollution, particularly when the car is new.
Research has indicated that in-cabin pollution can approach or exceed the levels of pollution in the air outside the car. In-cabin air quality is significantly better where a vehicle has a catalytic converter to reduce tailpipe emissions.
Tighter requirements for emission control and fuel efficiency technologies for new vehicles will take effect in Australia for diesel vehicles from 2003-06 and for petrol vehicles from 2002-05. Mandatory fuel quality standards will also contribute to future improvements in air quality inside vehicles.
Hints
Chemicals found inside vehicles in use can include:
Most people's homes contain a range of air pollutants. These include allergy promoting agents in the form of particles from dust mites (microscopic animals that feed on house dust and human detritus). Pollen is also an allergy-promoting agent and can be carried indoors on breezes or on clothing.
Gas stoves and heaters give off toxic gases such as formaldehyde, carbon monoxide and nitrogen oxides. Of particular concern are unflued appliances, because they do not have ducts to carry toxic gases outside the house.
The dust in carpets, roof and wall cavities, under floors and caught in floorboards and other gaps is easily released during renovation or cleaning.
Many new building products like particleboard, plywood and certain forms of foam insulation also release formaldehyde. In older homes, flaking paintwork can be a source of lead, which may be released while sanding for renovation.
Benzene, which is known to cause cancer, is found in environmental tobacco smoke, wood smoke and petrol fumes. An attached garage can be a significant source of pollution with petrol fumes seeping into the home. Vehicle exhaust from outdoor air can also affect homes located near busy roads.
Hints
Steps to reduce levels of air toxics in the home:
Workplaces may also contain new building products that give off formaldehyde and VOCs. Additionally, office equipment like photocopiers can give off ozone and small particles that can lodge in the lungs and cause disease.
Older buildings may contain asbestos, although this presents a health threat only if people are exposed to the material. Exposure can occur by breathing in fibres released into the air if products containing asbestos are disturbed during renovations or accidentally damaged. Activities such as building renovation or maintenance of air conditioning systems can also release cavity dust and paint dust into the workplace.
Australian building codes require that occupied rooms have adequate flow-through or cross-ventilation which can be provided by natural ventilation or by a mechanical ventilation system. Generally, indoor air is mixed with about 10 per cent to 30 per cent fresh outdoor air and recirculated, so pollutants can circulate through a building many times.
Many people have heard of 'sick building syndrome'. This syndrome is associated with chronic symptoms such as irritated or watering eyes, blocked or running nose, dry or sore throat, headache and lethargy. Surprisingly, even plants in the office can be a cause for concern because of the presence of fungi and their effect on people with allergies.
Indoor air quality in schools deserves particular attention. Children are generally more susceptible than adults to the effects of indoor air pollutants because they are smaller and have faster rates of metabolism. Air quality in schools is affected by the same factors as in other buildings, for example air conditioning, gas heaters, floor boards treated with lacquers, and motor vehicle emissions from neighbouring roads.
In 1993, seamless flooring was laid at a state school in Queensland. This type flooring consists of an epoxy resin base and a polyurethane sealing coat, that wet and then dries to form a hard surface.
The flooring was laid in an area adjacent to classrooms and offices. Children and complained of offensive odours during and after the floor laying. The contractor could not remedy the problem and the flooring was eventually removed. The was evacuated and was not reoccupied until 1996. Similar problems at a second school in 1994 led to an investigation by the Queensland Department of Public Built Environment Research Unit. This showed that the solvents xylene and isobutyraldehyde were responsible for the odours, mainly because the product been applied incorrectly. The epoxy base had been overly thinned with xylene insufficient drying time had been allowed between coats, so that solvents were trapped in the flooring and evaporated over a long period of time. The problem made worse by poor ventilation in the classrooms.
Tests of air quality in these and other Queensland schools were inappropriately compared to occupational exposure standards. This led to the finding that emissions were within acceptable limits, which caused further concern to the community. A medical evaluation concluded that it was highly unlikely that there was an increased risk of long-term health risks for the majority of the exposed population, but noted some incidence of chemical sensitivity, worsening respiratory problems other complaints.
[Ball M, 1999. Seamless Floors: A Case Study in Health Risk Management, in: Indoor Air Quality - A Report on Health Impacts and Management Options, Commonwealth Department of Health and Ageing, Canberra]