In 2007, EPA monitored air quality at 21 sites across Victoria, with:

• 13 in metropolitan Melbourne
• two in Geelong
• two in the Latrobe Valley
• one temporary site in country Victoria (Warrnambool for a 13-month period)
• three temporary bushfire monitoring sites (Wangaratta, Bairnsdale and Macleod).

Port Phillip region

Victoria

Air quality is assessed against the national and/or state objectives and goals shown in the table below.

Additional equipment was deployed to monitor bushfire impacts on air quality. The additional monitoring commenced in December 2006 and continued into 2007, and included:

• visibility at Wangaratta and Richmond,
• PM₁₀ at Wangaratta, Bairnsdale and Macleod, and
• ozone at Wangaratta and Macleod.

EPA provided regular advice on bushfires and air quality to affected communities during the bushfires. This included:

• information on how members of the community could assess the risks associated with bushfire smoke for themselves and
• advice about minimising potential health effects.

Smoke advisories, including health advice, were provided through the media during January.

In 2007, Victoria experienced severe bushfires that started in December 2006 and continued through to January 2007. Major fires occurred in alpine areas, northeast Victoria, Gippsland and western Victoria.

North-east Victoria and Gippsland were particularly affected by smoke during January. Air monitoring stations in Melbourne and rural areas recorded poor visibility and high particles levels (PM₁₀) on many days in January when smoke was transported from the fires by the prevailing winds. Overall, however, the impact of the bushfires on air quality was lower than that experienced in December 2006.

The bushfires in 2007 also led to unusually high levels of ozone. Bushfires emit large quantities of hydrocarbons and oxides of nitrogen, which can react to form ozone. Most bushfire affected monitoring stations reported elevated ozone concentrations on several occasions and reported at least one day in January when the ozone objectives were not met.

Apart from bushfires, air quality in 2007 was affected by:

• smoke from planned burning (mainly for fuel reduction) in April 2007
• windblown dust, often from distant sources. Windblown dust is typically coarse and tends to impact PM₁₀ more than visibility.
• urban sources, predominantly motor vehicle and wood heater emissions accumulating in stable atmospheric conditions. These stable conditions tend to occur on calm, cold autumn/winter nights. These urban sources typically impact visibility more than PM₁₀. When not properly managed, sources such as woodheaters can have a significant local impact.

An assessment against Victoria’s air quality objectives and goals is shown in the 2007 data tables.

In Melbourne there was a higher than usual number of days when the particle (particularly PM₁₀ and visibility) objectives were not met. Elevated particle levels and poor visibility occurred mainly on days affected by bushfires (in January) and planned burning (in April). Particle levels were also elevated on days affected by windblown dust or when local emissions, particularly from motor vehicles and wood heaters, were trapped in calm, highly stable conditions.

The ozone objectives were exceeded at most monitoring stations in Melbourne on one day in January due to bushfires. The ozone goal was met at all stations except Macleod, where there were two exceedances of the four-hour objective due to bushfires.

The air quality objectives for nitrogen dioxide, carbon monoxide and sulfur dioxide were met on all days in 2007.

Air toxics levels were monitored at Carlton, Mooroolbark and South Melbourne in 2007. Levels were low and met the limits specified in the National Environment Protection Measure (NEPM) for Air Toxics.

In Geelong, there was a higher than usual number of days when the particle (PM₁₀ and visibility) objectives were not met. As was observed in 2006, windblown dust was the major cause of high particle levels (rather than smoke from bushfires or planned burns). Due to these dust impacts, Geelong had more days that did not meet the PM₁₀ objective than any other station in 2007.

Whilst the ozone goal was met, the objectives were exceeded on one day (at Point Henry) in January due to bushfires.

The objectives for nitrogen dioxide, carbon monoxide and sulfur dioxide were all met.

In the Latrobe Valley, smoke from bushfires and planned burns resulted in a large number of days when the particle (as PM₁₀) and/or visibility objectives were not met. Due to proximity to the fires, the air quality impacts in the Latrobe Valley were greater than those experienced in Melbourne.

While the ozone goals were met, the bushfires resulted in one day in January when the four-hour ozone objective was exceeded at Moe and Traralgon.

The objectives for nitrogen dioxide and sulfur dioxide were met on all days.

Air toxics levels were monitored at Traralgon in 2007. Levels were low and met the limits specified in the Air Toxics NEPM.

In Warrnambool a 13-month monitoring campaign concluded in October. Like other areas of Victoria, the major impact on Warrnambool’s air quality in 2007 was smoke from bushfires, both in January from fires in NE Victoria and in February from fires burning locally and in Tasmania. These fires led to days not meeting the visibility objectives. The particles (as PM₁₀) and ozone objectives were met at Warrnambool in 2007.

EPA has published a separate report on the campaign monitoring at Warrnambool.

In Wangaratta, a 12-month monitoring campaign concluded in December. Wangaratta experienced significant bushfire impacts in January, with both visibility and particle (as PM10) objectives frequently exceeded. In addition, during the colder months of the year, a build up of pollutants (including smoke from wood heaters) on calm, cold autumn/winter nights led to poor visibility on many occasions.

Whilst the ozone goals were met, the bushfires resulted in one day in January when the four-hour ozone objective was exceeded at Wangaratta.

Air quality has changed very little in Melbourne over the past decade. Melbourne’s air quality is considered to be relatively good for a major metropolitan centre. Long-term trend graphs are available with the 2007 monthly data tables (PDF 201KB). These graphs update the analysis presented in EPA’s report on Victoria’s air quality in 2006 (publication 1140).

Melbourne’s air quality is better than or comparable to interstate and international cities in countries of a similar level of development to Australia. Improvements are necessary, however, to preserve Melbourne’s relatively good air quality given increasing pressures from population and economic growth and a changing climate. A comparison is presented in Victoria’s air quality – 2006 (publication 1140).