Recent Trends in Ozone and Particle Concentrations in the Sydney (Australia) Airshed

An overview is presented of changes in ground level ozone and atmospheric fine particles determined using ambient monitoring data collected at selected locations in Sydney, Australia. After removing seasonally, auto-regressive and moving average dependence from the selected time series, the trend of a selected series was modelled using the fractional long-term dependent component. The selected technique was able to detect the trend at a very small resolution. The method results were compared to the trends obtained using the Rao-Zurbenco method. For selected monitoring stations, between 1980 and 1993, there was a decrease in ozone concentrations followed by a slight increase between 1994 and 2002, and thereafter a stable concentration. Fine particle concentrations as measured by nephelometry, showed a significant decrease from 1980 to 1990, which stabilised beyond 1994.