Analysis of background ozone in the Sydney basin

It has been known that the "background ozone" level in urban cities is changing over the years. What is the background ozone and why this is changing is not entirely clear. This paper looks at one definition of background ozone level and using this definition to derive the background level of ozone using ambient quality data measured at the monitoring stations. From the derived background ozone level, it is possible to determine the change of background level from the early 1990 to the present day. The change or trend in background level at different monitoring stations will be accessed using the Long Range Dependent method and the results are shown to be not the same at different stations. This shows that the local conditions at each station are important in determining whether a quality management plan to reduce ozone below exceedance level is effective (or achievable) or not.