Particle concentrations have exceeded National Environmental Protection Measures (NEPM) Air Quality Standards since monitoring began in 1986. While exceedances of the PM10 24-hour standard show no clear trends, annual average PM10 concentrations in most regions are trending down. Exceedances of the PM2.5 24-hour standard and annual averages are both trending down.
Particle pollution is Queensland’s most significant air quality issue. A variety of sources emit particles into the atmosphere, including motor vehicles and industrial activities. Climatic conditions and the contribution of particles from dust storms, smoke from bushfires, agricultural burning and hazard-reduction burning have the most significant impact on particle 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 (PM2.5) are considered to have more significant health impacts due to their deeper penetration into the lungs.
Monitoring of PM10 is undertaken in all regions whereas PM2.5 is undertaken in South East Queensland (SEQ) and Gladstone only. While there has been no definite trend in the number of days exceeding the National Environmental Protection Measures (NEPM)standard for PM10 over the past decade, there has been a decreasing trend in the number of days of exceedances of the PM2.5 24-hourly average standard. Dust storms and bushfires caused many exceedances in 2009 and 2011. The high number of days (36) of exceedances of the Air NEPM standard for PM10 in Moranbah in 2012 related to a housing estate development around the monitoring station. Dust from building construction works immediately adjacent to the Woolloongabba monitoring station accounted for half of SEQ’s exceedances in 2014. Mount Isa is situated in a low rainfall area where winds associated with the passage of low pressure troughs through the region can result in high levels of windblown dust. Windblown dust is usually responsible for most exceedances of the Ambient Air Quality NEPM 24-hour PM10 standard. Above average rainfall in 2010 and 2016 across Queensland resulted in very few exceedances.
In the past decade, exceedances of the Air NEPM annual average PM10 standard occurred only once in Mackay (2009) and Mount Isa (2009) and twice in Moranbah (2012 and 2017); while exceedances of the Air NEPM annual average PM2.5 standard occurred only once in SEQ (2009) and once in Gladstone (2011). These were associated with dust storms and bushfires. PM10 and PM2.5 annual averages have remained fairly static over the past decade, although levels in SEQ, Gladstone and Townsville appear to be decreasing slightly. For the 2012-2017 period, annual average PM10 and PM2.5 in SEQ and Gladstone has been less than 75% of the relevant standard.
Higher temperatures predicted in the future 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.
Indicator: Trends in number of exceedances of NEPM air quality standards for particulate concentrations, and annual concentrations
Trends in number of exceedences of National Environmental Protection Measures (NEPM) Air Quality Standards for particulate concentrations, and annual concentrations, by airshed for 2000–2017.