ACT State of the Environment 2007
Issue: Air quality
Breathing good quality air is taken for granted by Canberrans. We are fortunate to live in a city where pollutants to our outdoor air are minimal, compared with other capital cities, due to our lack of heavy industry. Legislation enacted in December 2006 has now provided us with smoke-free air in all enclosed public places; a step in the right direction for indoor air quality.
Outdoor air quality in Canberra has not changed significantly over the reporting period. While the air quality is a problem in Tuggeranong in the winter months due to air temperature inversions, but there is a slight indication that air quality there is improving. This is likely to be due to the ACT Government's Wood Heater Replacement Program that provides subsidies to ACT households to replace old wood heaters with new gas heaters. However, it is too early to categorically accept this as the total reason. Air temperature inversions are not the only reason that particulates can exceed desired levels. Bushfires and dust storms can also contribute to reduced air quality. The high particulate matter levels in November–December 2006 and January 2007 were most probably caused by drift from bushfires in Tumut NSW and Gippsland and North East Victoria. No major bushfires occurred within the ACT's border during this same period, and no major dust storms blew across our city.
The majority of the Territory's locally produced atmospheric emissions continue to come from motor vehicles. In 2005–06 motor vehicles accounted for 26.4% of air emissions. Our dependence on motor vehicles as the main mode of transport will continue to contribute to this problem as long as vehicles remain running on petrol or other hydrocarbons. We are starting to travel less as a community. In fact, our average distance travelled, has decreased by 10% between 2003–04 and 2006 (Australian Bureau of Statistics, 2006b). This is due to a reduction in interstate trips by Canberrans. We are now below that of the Australian average at 13,600 kilometres for the first time in November 2006 (Australian Bureau of Statistics, 2006). It will be interesting to see if this trend continues in the longer term. The question of whether it's our awareness of the harm that vehicle emissions contribute to greenhouse gases, the increasing price of motor fuel, the availability of cheap air travel or a combination remains to be answered.
Ozone levels were recorded at higher levels in Civic than at Monash due to the greater concentration of motor vehicles in the city centre. Ozone is formed when sunlight promotes chemical reactions among pollutants that are emitted from motor vehicles. Unless we reduce traffic in Civic we can expect that concentrations of ozone will continue to remain high.
Other sources of emissions reported to the National Pollutant Inventory in the reporting period include landfill, agriculture, petrol stations, paints and other substances.
Indoor air quality
A range of studies have shown that Australians spend 90% of their time indoors (including within vehicles) yet there is no regular recording and little available data on indoor air quality in the ACT.
Various human activities, such as smoking and external factors (from outdoors) also impact on indoor air quality. Legislation banning smoking in public buildings and licensed premises in the ACT, enacted in December 2006 has greatly improved air quality in pubs, clubs and other establishments. While this is a significant step to improve indoor air quality, in some work places smokers congregate just outside buildings and fellow work colleagues sometimes need to walk through these areas. While this issue needs to be addressed it is likely to be best done at the work level rather than through legislation. The best overall approach is to focus on assisting people to stop smoking and this is being done through various health campaigns.
Workplaces may have specific pollutants depending on the nature of the work. Often office buildings have higher concentrations of pollutants than in houses and the ventilation in office blocks is substantially less than houses. Occupational health and safety regulation cover air quality in the workplace.
The main indoor air pollutants are:
- formaldehyde from pressed wood products and laminates;
- volatile organic compounds (VOCs), from some synthetic fabrics, varnishes, cleaning products, office equipment, and various building products such as paints, carpets and glues;
- nitrogen dioxide, from burning natural gas (although if heaters and cookers are correctly flued most of the pollutant is dispersed outside);
- carbon monoxide, from wood-burning (again, the fluing and chimney efficiency has a significant effect), from internal combustion engines (such as cars idling) and from cigarette smoke.
Some of the more worrying indoor pollutants, listed above, are chemicals released from some types of materials used to construct and fit a new house or renovate an existing one. Emissions of pollutants into indoor air are therefore usually worse in brand new houses or renovated homes, but normally decline to insignificant levels over the first year of the life of the house (or the renovation). Usually the situation will be exacerbated if the house is kept tightly sealed and not ventilated, to minimise the loss (or gain) of heat energy via air movements between the house and outside. In practice, however, while new houses (meeting minimum energy performance standards) are more tightly sealed than most older houses, very few houses in the ACT even approach the level of air tightness which is normal in new houses in North America or northern Europe. Moreover, the ACT climate is such that, even in mid winter, there are few if any days on which opening some windows for ventilation in the middle of the day will result in significant heat loss. Consequently, while the level of air pollutants in new houses may well be higher than in older houses, the absolute levels are unlikely to be a cause for concern.
Conversely, old houses may suffer from other problems related to indoor air quality. Deep-seated mould may release spores; old carpets, furniture and mattresses may harbour dust mites. However, the dust mite problem is less severe in the ACT than in coastal Australia because of the drier climate.
Other factors in both new and old homes, such as treatment of a house for pests, or use of cleaning solvents and paints, may also introduce a range of air pollutants. A good airing of any house is a sensible precautionary practise. This same principle applies to other buildings.
Are we monitoring adequately?
In response to a recommendation by the Commissioner in the State of the Environment Report 2003 the ACT Government purchased three laser continuous particle samplers and installed them in Civic, Monash and Belconnen. However, at this time there is no data available for analysis. Once data becomes available it should be interpreted and information provided to the public.
There is no regular recording of indoor air quality and few data are available on indoor air quality in Canberra buildings. Data available from elsewhere is sparse.
Unlike other jurisdictions, Canberrans know little about the air quality in our city and our houses. It is important that Canberrans have a better understanding of the quality of air they are breathing and the effects our actions and choices have on our air quality.
The following recommendations are made to the ACT Government with a commitment from the Commissioner to assist in advancing their implementation.
1. Make outdoor air quality data and information available to the public through an annual air quality report prepared by the Environment Protection Agency.
2. Gain a better understanding of indoor air quality to inform building design, maintenance and use by:
- Monitoring indoor air in selected public and private buildings with the results to be made public and used to inform management of the building.
- Providing information to the community on the importance of regularly introducing fresh air into buildings.
- Advising occupants of new or renovated buildings and those with new furniture and fittings (such as carpets and underlays) to air the house as much as possible in the first few days following installation.
Data sources and references
The Indicators drawn on for this Issues Paper were:
Australian Bureau of Statistics Australian Bureau of Statistics 2006b, Survey of Motor Vehicle Use, 01 Nov 2004 to 31 Oct 2005, cat. no. 9208.0, available at <http://www.abs.gov. au/AUSSTATS/abs@.nsf/allprimarymainfeatures/2FEC26084579A43B CA2571E1001E7F28?opendocument>