Air Quality

Region

| Assessment | Monitoring | Implications | Background |
| Indicators used to assess this issue |

Assessment

In this Issue we concentrate mainly on the quality of the air in the lower atmosphere, which directly affects human well-being.

The air quality in the Australian Capital Region as a whole is likely to be very good because of the lack of heavy industry or concentrated urban areas. However, there is no routine monitoring outside of Canberra, except for one station at Cooma, so it is not possible to make a definitive statement for the Region.

The main sources of carbon monoxide in the Region are motor vehicles, bushfire hazard reduction burnoffs, greenwaste burnoffs at tips and residential solid fuel fires. Carbon monoxide concentrations are generally highest on winter evenings because of emissions from vehicle usage and a surge in wood-burning heaters starting to operate as people return home. Concentrations can build up and the pollutant may be temporarily trapped by atmospheric inversions which are most likely on clear winter evenings. With the reticulation of natural gas into many of the Shires during the reporting period, Councils are hopeful that households will start to change over from wood to gas, improving air quality.

Monitoring

The National Environment Protection Council introduced National Environment Protection Measures (NEPMs) on 26 June 1998, one third of the way into the reporting period. The NEPM for ambient (outdoor) air quality contains a formula for the number of monitoring stations required within a region, based on population numbers. None of the Shires are required to monitor air quality according to this formula. The ACT has three sites monitoring air quality at Civic, Monash and Woden.

Another interesting new development by the National Environment Protection Council is the creation of a NEPM for diesel emissions that will shortly come into effect, although the Australian Capital Region does not suffer greatly from diesel emissions.

Without monitoring stations in place across the whole Region it is not possible to know if local effects are causing pollutant accumulation.

Implications

The link between high particulate concentration in air and diminished respiratory health is established, but the effects may take some time to show up in a population. There is also likely to be wide individual variation both in susceptibility and in lifestyle factors (smoking) which could ameliorate or exacerbate environmental exposure.

In the absence of heavy industry or power generation, most aspects of air quality are strongly influenced by motor vehicles. Results for motor vehicle use tell us that the Australian Capital Region comes in below the Australian average for distance travelled, but the Region's vehicles are still being fuelled by leaded fuel at a higher rate (50%) than the Australian average (40%). Air pollution is not a serious problem, but places where there is now heavy and continuous vehicle traffic such as the Hume, Kings and Princes Highways and also through the major population centres, especially during the peak tourist season, are doubtless suffering reduced air quality from time to time. A worthwhile objective to consider is a campaign to spread awareness that vehicle exhaust is polluting, and to encourage motorists (as well as drivers of heavier vehicles) to switch off engines when idling for prolonged periods - for example, in long traffic queues or when stopping to deliver goods.

In addition, it should not be forgotten that vehicle exhaust contains many pollutants that are not routinely monitored. Many of these are toxic or carcinogenic. The time these spend in air (their residence time) is generally thought to be short, and eventually most of these compounds are oxidised into less harmful forms. However, very small particles containing toxic organic compounds can be inhaled or can fall out on vegetation near roadsides.

Indoor air quality is variable but is not routinely monitored. Given the fact that people spend most of their time indoors, indoor air quality is of greatest significance for health. Previous State of the Environment Reports have covered this issue.

Background

Air quality can be assessed on broad or fine scales: an entire region, an urban airshed, an individual valley or a room within a building.

Although quality may be excellent when assessed across a region of thousands of square kilometres, individual 'hotspots' within such an area may periodically or continuously suffer from lower air quality. The limitations of monitoring mean that not all such hotspots can be detected. They may often relate to a suite of pollutants emitted as a result of a particular localised activity - for example, occupational exposure to solvents from petroleum products or dry-cleaning fluids that might specifically affect workers on the premises.

Air quality is of concern because of its effects on human health and, in more severe cases, agricultural production and the built environment. The careful siting and rigorous operation of measuring devices is essential to monitor air quality. However, this is a complex task and needs regular updating.

Growth in the Region, its vehicle fleet and various industrial activities are likely to increase emissions to the air in the future.

Indicators used to assess this issue