Air quality in 2007
Overview
Victoria’s air quality in 2007 was generally good, with air quality objectives (other than for particles, visibility and ozone) typically met.
The major impacts on Victoria’s air quality in 2007 were the bushfires experienced in January (which led to days when the particles, visibility and ozone objectives were not met) and planned burning for fuel reduction purposes in April (particles and visibility objectives were not met).
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Windblown dust and accumulation of combustion particles in calm, highly stable air also resulted in a number of days when the particle objectives were not met.
Under climate change Victoria is predicted to become hotter and drier. As a result bushfires (and dust storms) are expected to become more frequent, affecting our air quality. Air quality in 2007 provides an indication of the potential effects of climate change.
Compared to similar urban centres, Melbourne’s air quality remains relatively good, with little change over the last decade despite increasing pressures such as population growth. Maintaining and improving Victoria’s air quality will be a challenge in the context of expected continued population growth and the impacts of climate change.
Publications
- For monthly air quality data and trend graphs download Victoria's Air Quality 2007 - Air Monitoring Data (Updated version Dec 2008)
(Adobe PDF format, 201 KB) - For air quality statistics and compliance with national requirements download EPA Publication 1231 – Air monitoring report 2007 – Compliance with the National Environment Protection (Ambient Air Quality) Measure (Adobe PDF format, 846KB)
Frequently Asked Questions
- Where does EPA monitor?
- How do we assess air quality?
- What effect did bushfires have on air quality in 2007?
- How did EPA respond?
- What other factors affected air quality?
- What happened in my region?
- What are the long-term trends?
- How does Melbourne compare with other cities?
Where does EPA monitor?
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 13 month period)
- three temporary bushfire monitoring sites (Wangaratta, Bairnsdale and Macleod).
Click here for maps showing locations of monitoring stations: Port Phillip Region and Victoria.
How do we assess air quality?
Air quality is assessed against the national and/or state objectives and goals shown in the table below.
Table:State and national air quality objectives and goals
| Pollutant | Averaging period | Objective | Goal to be achieved by 2008 |
| Particles as PM10 | 1 day | 50 μg/m3 | 5 days a year |
| Particles as PM2.5 | 1 day | 25 μg/m3 | not applicable |
| 1 year | 8 μg/m3 | ||
| Visibility-reducing particles | 1 hour | 20 km | 3 days a year |
| Ozone | 1 hour | 0.10 ppm | 1 day a year |
| 4 hours | 0.08 ppm | 1 day a year | |
| Carbon monoxide | 8 hours | 9.0 ppm | 1 day a year |
| Nitrogen dioxide | 1 hour | 0.12 ppm | 1 day a year |
| 1 year | 0.03 ppm | none | |
| Sulfur dioxide | 1 hour | 0.20 ppm | 1 day a year |
| 1 day | 0.08 ppm | 1 day a year | |
| 1 year | 0.02 ppm | none | |
| Lead | 1 year | 0.50 μg/m3 | none |
What effect did bushfires have on air quality in 2007?
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.
For more information see Air Quality During the 2006-07 Victorian Bushfires. (Adobe PDF format, 940 KB)
How did EPA respond to the bushfires?
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.
Further information on Bushfires and Air Quality is available on EPA’s web site.
What other factors affected air quality?
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.
What happened in my region?
An assessment against Victoria’s air quality objectives and goals is shown in the 2007 data tables. (Adobe PDF format, 201KB)
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 exceedences of the 4-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.
Whilst the ozone goals were met, the bushfires resulted in one day in January when the 4-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 4-hour ozone objective was exceeded at Wangaratta.
What are the long-term trends?
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 (Adobe PDF format, 201KB). These graphs update the analysis presented in EPA’s report on Victoria's air quality in 2006. (Adobe PDF format, 521KB)
How does Melbourne compare with other cities?
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 EPA’s report on Victoria's air quality in 2006. (Adobe PDF format, 521KB)
Air quality summary
Tuesday 24 November 2009: Summary for the 24 hours to 3 PM: FAIR air quality at Footscray (due to local dust), and GOOD air quality elsewhere.
Forecast: GOOD air quality is expected in Melbourne tomorrow [Wednesday]