In Queensland, we have measured visibility-reducing particles daily at three locations since 2000:
- Mackay
- Gladstone
- Southeast Queensland.
From 2011 to 2015, monitoring occurred in Ayr.
Since 2018, monitoring has occurred in Townsville.
Factors affecting visibility
A build-up of fine airborne particles can reduce how far we can see through the air.
The Environmental Protection (Air) Policy 2019 (Air EPP) sets a visual amenity objective of 20 kilometres, i.e. on a fine day, it should be possible to see an object 20 kilometres away.
Reductions in visibility are mainly attributable to burning activities, such as:
- combustion in motor vehicles and industry
- bushfires
- fine particles resulting from photochemical smog formation
- windblown dust.
In the Mackay and Ayr (Burdekin) regions, smoke from cane burning in the Burdekin region and from cane trash burning in the Mackay region can also reduce visibility.
Visibility results
- Overall, since 2000, fewer days have exceeded the Air EPP goal.
- Since 2002, most regions have experienced ten days or less of low visibility each year.
- All Queensland regions (where monitoring was in place) had more days of exceedance in 2000, 2001 and 2009 due to very dry conditions and widespread bushfires.
- Southeast Queensland had additional days of poor visibility in 2004, 2012, 2019 and 2023 due to widespread bushfires and increased hazard-reduction burning in the region in these years.
- Gladstone had additional days of poor visibility in 2011, 2015, 2017 to 2020 and 2023 due to widespread bushfires and increased hazard-reduction burning in the region in these years.
- Mackay had additional days of poor visibility in 2000 and 2001 due to more extensive cane burning in the Pioneer Valley west of Mackay in these years. Since then, there has been a gradual progression to almost 100% green cane harvesting, resulting in fewer reduced visibility days in Mackay.
- Ayr experienced more than ten days of poor visibility in 2011 and 2014 due to increased sugar cane burning before harvest during these years.
- Since monitoring commenced in 2018, the maximum number of days of poor visibility in a year in Townsville has been four.
