Monitoring dates: February 2007 to January 2008.

Air toxics monitored: Benzene, benzo(a)pyrene, formaldehyde, toluene and xylene.

Sampling frequency: 24-hour samples once every six days.

Number of samples analysed: Benzene, toluene and xylene – 60; benzo(a)pyrene – 60; formaldehyde – 54.

Location: EPA Traralgon air monitoring station, Kay Street, Traralgon.

Results of monitoring

Benzene, benzo(a)pyrene, formaldehyde, toluene and xylene were monitored in a residential area in Traralgon. The primary focus of this study was to monitor air toxics levels in a large regional centre, located near the major power generators.

The average concentration of benzo(a)pyrene remained below the health-based monitoring investigation level, with most samples recording levels below the chemical analysis detection limit.

We found detectable levels of benzo(a)pyrene on a number of days during colder weather. We expected this because:

• wood heaters are used more during winter
• polycyclic aromatic hydrocarbons (PAHs) from combustion sources form more readily when the ambient temperature is low
• there is generally less dispersion of pollutants in winter, due to lower winds.

Levels of benzene, formaldehyde, toluene and xylene were low — below monitoring investigation levels.

24-hour results

Not applicable: A 24-hour investigation level is not specified for benzene and benzo(a)pyrene.

Not detected: Air toxic was below measurable levels.

Not sampled: No result is available due to sampling failure or error.

ppb: parts per billion (for every one billion litres of air there is one litre of the pollutant).

ng/m³: nanograms per cubic metre (1 billionth of a gram per cubic metre).

Detection limits are as follows: