Particulate concentrations

Key Finding

Particle pollution is Queensland’s most significant air quality issue.

Air particles come from many sources. While motor vehicles and industry play a part, dust storms and smoke from bushfires and agricultural or hazard-reduction burning have the most significant impact on particles levels, and year-to-year variations.

The particles generated can range in size from more than 50 micrometres (µm) in diameter to less than 1µm and can impact on health and amenity.

• Smaller particles—less than 10µm in diameter (PM₁₀)—can affect human health.
• Particles smaller than 2.5µm in diameter (PM_2.5) are considered to have more significant health impacts due to their deeper penetration into the lungs.

Monitoring of PM₁₀ is undertaken in all regions. Prior to 2018, PM_2.5 was undertaken in South East Queensland (SEQ) and Gladstone only. It’s now monitored in South West Queensland (SWQ), Townsville, Blackwater, Moranbah and Mackay.

Peaks in PM₁₀ exceedances and annual average concentrations across all Queensland regions are associated with years when major dust storms occurred (2002, 2009 and 2019), with localised dust or bushfire smoke impacts responsible for increases in some regions in other years (e.g. bushfires in the Gladstone region in 2012 and 2018). Overall, PM₁₀ levels are higher at inland locations compared to coastal areas due to lower rainfall giving rise to more windblown dust. In the decade prior to 2018 exceedances of the PM₁₀ 24-hour standard of 50µg/m³ showed a slight overall decrease in most regions, while annual average PM₁₀ concentrations showed no clear trend.

In the past decade, exceedances of the Ambient Air Quality NEPM annual average PM₁₀ standard of 25µg/m³ occurred only once in SWQ (2019), Blackwater (2019) and Mackay (2009), twice in Mount Isa (2009 and 2019) and 4 times in Moranbah (2012 and 2017 to 2019).

• Since 2009, windblown dust has been responsible for over 70% of all exceedances of the Ambient Air Quality NEPM 24-hour PM₁₀ standard, primarily from wind erosion of bare ground during dry conditions. This is particularly the case for inland locations with lower annual rainfall, such as Mount Isa.
• 7 of SEQ’s 15 days of PM₁₀ exceedances in 2014 were due to dust from building construction works next to 1 monitoring station.
• Moranbah’s 36 days of PM₁₀ exceedances in 2012 related to dust from a housing estate development around the monitoring station.
• Extremely dry conditions triggered more dust storms and bushfires in 2018 and 2019, resulting in PM₁₀ levels in all regions increasing.

Peaks in PM_2.5 exceedances and annual average concentrations are largely associated with years with heightened bushfire activity (2009, 2011 (Gladstone region), 2018 and 2019). In the decade prior to 2018 both exceedances of the PM_2.5 24-hour standard of 25µg/m³ and annual average PM_2.5 concentrations were trending down.

There were fewer years of exceedance of the Ambient Air Quality PM_2.5 annual average standard of 8µg/m³ in the decade to 2019: once in SWQ (2019) and twice in SEQ (2009 and 2019).

• Since 2009, smoke from vegetation fires has been responsible for over 80% of all exceedances of the Ambient Air Quality NEPM 24-hour PM_2.5 standard.
• Extremely dry conditions triggered more dust storms and bushfires in 2018 and 2019, resulting in PM_2.5 levels in all regions increasing.

Climatic conditions exert the greatest influence on year-to-year variations, with the number of exceedances declining in wetter years (e.g. 2010 and 2016 when there were 3 days or less) and increasing in drier years (e.g. 2002, 2009 and 2019 when regions experienced up to 33 exceedance days) due to higher windblown dust levels and rises in the number of vegetation fires and area burnt. Higher predicted temperatures and lower predicted rainfall as a result of climate change are likely to increase the occurrence of particle pollution with conditions leading to more prevalent dust storms and bushfires.

More information:

• Air quality

Relevant Sustainable Development Goals’ targets

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