Two decades of trends in urban particulate matter concentrations across Australia

Alma Lorelei de Jesus; Helen Thompson; Luke D Knibbs; Ivan Hanigan; Lilian De Torres; Gavin Fisher; Henry Berko; Lidia Morawska

doi:10.1016/j.envres.2020.110021

Two decades of trends in urban particulate matter concentrations across Australia

Environ Res. 2020 Nov:190:110021. doi: 10.1016/j.envres.2020.110021. Epub 2020 Aug 9.

Authors

Alma Lorelei de Jesus¹, Helen Thompson², Luke D Knibbs³, Ivan Hanigan⁴, Lilian De Torres⁵, Gavin Fisher⁶, Henry Berko⁷, Lidia Morawska⁸

Affiliations

¹ International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
² School of Mathematical Sciences, Queensland University of Technology, Brisbane, QLD, 4000, Australia. Electronic address: helen.thompson@qut.edu.au.
³ School of Public Health, The University of Queensland, Herston, QLD, 4006, Australia. Electronic address: l.knibbs@uq.edu.au.
⁴ School of Public Health and University Centre for Rural Health, The University of Sydney, Sydney, NSW, 2006, Australia. Electronic address: ivan.hanigan@sydney.edu.au.
⁵ Climate and Atmospheric Science, Science, Economics & Insights Division, Department of Planning, Industry and Environment, Sydney, NSW, 2141, Australia. Electronic address: Lilian.DeTorres@environment.nsw.gov.au.
⁶ Environment Protection Authority Victoria, Melbourne, VIC, 3001, Australia. Electronic address: Gavin.Fisher@epa.vic.gov.au.
⁷ Environment Division, Department of Environment and Natural Resources, Darwin, NT, 0801, Australia. Electronic address: Henry.Berko@nt.gov.au.
⁸ International Laboratory for Air Quality and Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia. Electronic address: l.morawska@qut.edu.au.

PMID: 32784017
DOI: 10.1016/j.envres.2020.110021

Abstract

Australia is a highly developed country with low population density. Capital cities are situated mainly around the coastline and are subjected to different meteorological conditions. This complex set of drivers is expected to result in varying trends in particulate matter (PM) mass concentrations in urban ambient air across the country. Thus, the aim of this study was to determine the long-term trends in PM₁₀ and PM_2.5 concentrations in capital cities, and to analyse the factors that influenced such trends. The spatial variability of PM concentrations within the capital cities was first established to identify representative stations. Then trends were determined using the Mann-Kendall trend test, Sen's slope, and the generalised additive model. The results show that, in general, the PM concentrations in Australian cities are relatively low (12.1-21.7 μg m^-3 mean daily PM₁₀ and 4.6-8.7 μg m^-3 mean daily PM_2.5) and within the WHO daily limit 95% of the time. Over the past two decades, very small declines of 8.0 × 10^-5-1.1 × 10^-3 μg m^-3.yr^-1 for PM₁₀ and 7.7 × 10^-5-2.6 × 10^-3 μg m^-3.yr^-1 for PM_2.5 were observed while some stations exhibited increase in concentration based on available data; more stations showed a significant monotonic decline for PM₁₀ than PM_2.5. This is attributed to the effectiveness of the implemented emission reduction policies particularly for vehicle exhaust and power generation, given the simultaneous increase in the demand for energy and the number of vehicles over the last two decades. Regarding climate, in the coastal cities of Sydney and Brisbane, high rainfall and strong winds aid in maintaining low PM concentrations despite the significant anthropogenic emissions, while higher PM levels in Darwin can be attributed to its tropical savannah climate, which makes it prone to bushfires and necessitates regular prescribed burnings. PM concentrations increase when exceptional events such as bushfires and dust storms are induced by the extreme climate variability. Further reduction of PM concentrations in Australian cities is unlikely, considering the expanding urbanisation and the changing climate.

Keywords: Australian cities; PM(10); PM(2.5); Spatial variability; Temporal variability.

MeSH terms

Air Pollutants* / analysis
Air Pollution* / analysis
Australia
Cities
Environmental Monitoring
Particulate Matter / analysis
Seasons

Substances

Air Pollutants
Particulate Matter