Issue: Air Quality

Download pdf version here ( 137Kb )

Has air quality changed?

Canberrans who spent hours wiping red dust off the window sills may wonder what the severe weather events in the last few years did to air quality. In fact, outdoor air quality has not changed significantly since the 2000 State of the Environment Report, except for the period around the January 2003 bushfires.

Based on available data, Canberra’s air quality is good most of the time. This is due to the lack of heavy industry, the absence of concentrated high-density urban development and the relatively small population. Clean air is a major attraction of the area.

Severe climate events—fires and dust storms—marked this reporting period 2000–03. They caused most of the recorded 22 failures to meet national standards for clean air in regard to haze or fine airborne particles (PM10). Seventeen of those failures were in 2003; 12 of them were in January of that year.

On 18 January, the main day of the 2003 fires in the ACT, the Monash monitoring station recorded a reading of 193 micrograms per cubic metre of PM10. This is almost four times the standard of 50 micrograms per cubic metre. With ongoing fires, the amount of particulate matter in the air remained high for many more days, reaching nearly 328 micrograms per cubic metre on 30 January.

On 20 March 2003 air pollution worsened again during a dust storm. At Monash, 350 micrograms of PM10 (seven times the standard) was recorded. Two major dust storms in October and November 2002 also reduced air quality. PM10 is one of the six pollutants in the National Environment Protection Measure (NEPM) for Ambient Air Quality (see air quality standards). The goal under this standard is that by 2008 there will be no more than five failures for PM10 in any one year.

Other pollutants were also recorded at greater than usual levels as a result of the fires. Both the one-hour and the four-hour permissible ozone values were exceeded in January 2003. (No more than one failure for ozone in a year is the target under the national air quality standards.)

On a day-to-day basis, emissions from motor vehicles continue to have the greatest impact on outdoor air quality, with smoke from wood-burning fires coming a close second during winter—particularly when there is little wind or when there is an air temperature inversion in the Tuggeranong Valley. Although the standard for PM10 is rarely exceeded as a result, it is widely believed that smoke does pose a chronic problem in the ACT.

In regard to industry, four facilities operate under an environmental authorisation and are required to report on their air emissions to Environment ACT. These and several other facilities are listed in the National Pollution Inventory, but the total amount of pollution they generate is small in relation to the area of the ACT. For this reason they are unlikely to significantly worsen Canberra’s air quality.

What is unknown is whether there are hotspots of pollution near these facilities from time to time. This is because none of the facilities is near any of the fixed air quality monitoring stations. Mobile monitoring would be useful to occasionally check the air quality downwind of these facilities.

What about indoor air quality?

Air pollutants can also accumulate within a building. Indoor air quality is of particular importance because this is where the majority of people spend most of their time. However, there is no routine monitoring of indoor air quality in the ACT and no data are available for ‘normal’ buildings.

The best-known indoor air pollutant is tobacco smoke. Smoking is banned in most ACT public buildings and enclosed public spaces. In many licensed premises smoking is permitted only in designated smoking areas. A recent study conducted by the ACT Health Protection Service found tobacco smoke in more than 80% of the ‘smoke-free’ areas and even in adjacent non-smoking premises.

Are we monitoring adequately?

There are ongoing concerns about the adequacy of air quality monitoring in the ACT.

Outdoor air quality is routinely monitored at two stations in Canberra—Monash and Civic. Monash is the official monitoring station for the NEPM for Ambient Air Quality.

Daily monitoring of PM10 began at Monash in March 2002, bringing the ACT into compliance with the NEPM. The new system has gone through a ‘teething’ period leading to data gaps; however, the old monitoring system was continued to allow for those problems and also to compare results from different instrumentation.

The new daily monitoring confirms there were probably unrecorded failures to meet air quality standards during the reporting period (and, no doubt, historically). The Christmas 2001 fires, for example, occurred before the new equipment was installed in Monash. There are no data for PM10 during that period for either Monash or Civic because the main fires occurred between the readings taken on 21 and 27 December. There are numerous other gaps.

The Commissioner has ongoing concerns that these two monitoring stations may not adequately represent air quality across the whole urban area. These concerns are strongly shared by members of the Reference Group that provided technical advice for this report.

Other concerns about the current monitoring regime are:

  • the re-positioning of the Civic monitoring station in August 2002 may invalidate comparisons between values recorded before and after the move
  • the intermittent nature of Civic’s monitoring obscures any transient pollution episodes at that location
  • fixed monitors can fail to record localised pollution occurring elsewhere.

Some pollutants disperse more readily than others and hotspots of poor air quality can exist within a larger area in which general air quality is good. A welcome development is the National Environment Protection Council requirement for monitoring very fine particles (PM2.5). Also welcome is the ACT Government’s allocation of resources to provide for this monitoring from 1 July 2004. A draft NEPM for air toxics—benzene, toluene, formaldehyde, xylene, and polycyclic aromatic hydrocarbons—is under consideration.

Although it is relatively difficult to monitor air toxics, it is likely that monitoring will eventually be required. If not, it still would be advisable to test Canberra’s air from time to time in different places. It would help if the ACT Government undertook some experimental mobile monitoring at likely hotspots.

Monitoring would also be useful in the case of the crematorium, which is not required to carry out regular stack-testing—although Environment ACT can require testing at any time. The last such test, which met national guidelines, was reported in December 2000. More evidence that the facility is complying with emissions criteria is desirable.

Can we make a difference?

Government action—both nationally and within the ACT—has improved some aspects of Canberra’s outdoor air quality. Airborne lead is the outstanding example.

In the past 10 years, the introduction of lead-free petrol followed by full adoption of lead replacement fuel has seen Canberra’s concentration of airborne lead fall to a level close to that occurring naturally. The dramatic change has been documented since the first ACT State of the Environment Report in 1994 and it is a clear environmental success story.

Action at point sources has also yielded improvements. The current Stericorp incineration process, which uses high frequency radiowave electro-thermal deactivation, results in much lower air emissions than did the Totalcare incinerator that ceased operation during the reporting period.

Air quality during the winter months can be improved by reducing solid fuel burning. The ACT Government’s actions on wood-burning are a step in the right direction, involving community education and the wood heater replacement subsidy scheme introduced in the 2003–04 Budget, allocating $200,000 over 2003–04 and 2004–05. Subsidies of up to $800 are available to replace older polluting wood heaters with gas or electric installations. This may bring results, and monitoring is needed to prove it.

The ACT Government has taken this up in the 2003–04 Budget with $50,000 allocated to buy the equipment required to monitor PM2.5. An extra $50,000 has been set aside for 2004–05 to buy nephelometers—a useful substitute for directly monitoring fine particles—with the aim of determining the true extent of smoke pollution across Canberra. The nephelometers can later be used for mobile monitoring once a correlation has been determined between results from the nephelometers and the fixed PM2.5 instrument.

Still the most significant factor in deteriorating outdoor air quality is the motor vehicle. The number of vehicles registered in the ACT continues to increase due to growth in population and increasing urban sprawl, but this does not necessarily translate into a proportional increase in air pollution.

Newer cars, smaller cars and any vehicles with wellmaintained engines and emission control equipment will usually emit smaller quantities of most pollutants. In addition, stricter emissions standards apply to newer vehicles which emit far less pollution than older designs.

The average age of ACT private motor vehicles is about 10 years. This puts most in compliance with the 1986 legislation (ADR 37/00) that restricts emissions of carbon monoxide, hydrocarbons and oxides of nitrogen.

Stricter standards are applied in Europe and, if adopted here, would further help reduce the amount of pollution per vehicle kilometre. This is a Commonwealth Government responsibility.

While setting emissions standards is outside its mandate, the ACT Government should continue to promote the use of low-emission vehicles. One means is by complying with the Diesel Vehicle Emissions NEPM, which came into effect in June 2001.

This NEPM aims to reduce exhaust emissions from diesel vehicles by improving compliance with the relevant in-service emissions standards.

The ACT Government’s response has been to focus on a smoky vehicle program and to reduce the number of diesel buses on the road. Starting to lead by example, ACTION currently operates two compressed natural gas-powered buses, and a small number of alternative fuel and hybrid vehicles have been leased for the ACT Government fleet (two Prius and one compressed natural gas four wheel drive).

What does this mean for the future?

Maintaining good air quality is a complex issue and goes beyond any single jurisdiction.

Activities in a city like Canberra have an impact on the atmosphere—not just locally, but also globally. We use a lot of hydrocarbon-based fuel, such as petrol and diesel, and this pollutes Canberra’s air as well as contributing to the Greenhouse effect. Over the long term this consumption is not sustainable because the fuels will run out.

The lesson for the future is that we urgently must increase the effort to establish renewable energy sources, as well as to reduce energy demand.

That said, it is also clear that renewable energy sources are not always benign. Wood for fires is a renewable fuel, provided it is harvested at a sustainable rate and without destroying ecological communities, but its consumption pollutes the air. Wind power is admirable, but large windmills are expensive, visually obtrusive and may be noisy.

Commissioner's recommendations

In consultation with the Commissioner for the Environment, the ACT Government should:

  • use mobile air quality monitoring to measure and record air quality at busy intersections, near known point sources, and in other parts of Canberra that may be susceptible to high levels of airborne particles and other pollutants
  • examine how indoor air quality may be monitored in the ACT
  • promote and provide incentives for the use of low-emission vehicles by Government agencies.

living sustainably

Click to expand sitemap