Associations Between Ambient PM_2.5 Concentrations and Respiratory Symptoms in Melbourne, 1998–2005

Abstract

Particulate matter (PM) has been widely associated with adverse effects on respiratory health, both overseas and in Australia. This study aimed to investigate the impacts of ambient particles of <2.5 μm diameter (PM_2.5) in Melbourne on adverse respiratory symptoms. Two cohorts of adults were recruited in 1992–1998, and completed detailed respiratory questionnaires in 1998–1999 and 2004–2005. The mean age at baseline was 37.2 years, 55% were female, and the mean time lapsed between the baseline and follow-up questionnaires was 5.2 years. PM_2.5 exposure was assessed from gravimetric data and routine nephelometry at monitoring stations located centrally with respect to the residence of most participants. Daily exposures to PM_2.5 were averaged over the previous 12 months and mean daily exposure was 6.8 μg/m³. Logistic regression models were used to examine associations between PM_2.5 exposure and adverse respiratory symptoms. Adjustment was made for age, gender, current smoking status, and medication use, but further adjustment for atopy did not alter the results. There was insufficient variability in PM_2.5 exposure among participants over the study period to provide convincing evidence for or against associations between PM_2.5 and adverse respiratory symptoms.

This research was funded by the National Health and Medical Research Council, (NHMRC) Australia. The authors thank Bim Graham and John Gras of CSIRO Marine and Atmospheric Research for the installation/monitoring of the Highett Partisol sampler and helpful comments on the article, respectively. Additional nephelometry data was obtained from the Victorian EPA.