While the past decade has seen a downward trend in the number of days with reduced visibility throughout Queensland, significantly more days were affected in 2009 and 2011, and in Gladstone in 2015 and 2017, due to bushfires.
A build-up of fine airborne particles can reduce how far we can see through the air. The Environmental Protection (Air) Policy 2008 provides a visual amenity objective of 20km. This means it should be possible on a fine day to see an object 20km away.
Reductions in visibility are largely attributable to burning activities such as combustion in motor vehicles and industry, bushfires and the fine particles resulting from photochemical smog formation. While bushfires and dust storms can also affect the Mackay and Ayr (Burdekin) regions, smoke from cane burning in the Burdekin and from cane trash burning in the Mackay region also can reduce visibility.
While fewer days have exceeded the Air EPP goal since 2000 overall, all regions experienced a higher number of days of exceedance in 2009 and 2011. This also was true of South East Queensland in 2012 and Gladstone in 2015 and 2017. A higher than usual number of grass fires and bushfires influenced these exceedances.
Trends in number of exceedences of Air Environmental Protection Policy (EPP) goal for visibility-reducing particles by airshed for 2000-2017.