Spatial distribution characteristics of some air pollutants in Sydney Original Research Article

Spatial distribution characteristics may be used to help in siting of air monitoring stations. This technique is also helpful in predicting variations in the concentrations of air pollutants due to changes in meteorology. This paper discusses the spatial distribution patterns at a number of monitoring sites in Sydney. The pollutants modelled are ozone, nitrogen oxides and particles as determined by nephelometry. Concentrations, as monthly averages, covering a summer and winter period, are used. Spatial cross-correlation of time series between sites is also investigated. The correlation analysis shows that for most pollutants, the effect is only significant within 30 km around the site. The daily variations in correlation between sites, caused by changing meteorological conditions, can be minimised by deriving the correlation coefficient for each hour in a particular year. This allows the correlation pattern at each hour to be seen and the average effect of meteorology can be revealed by the changing pattern over a 24 h period. This approach is used for each hour over 1993 and 1994, based on the correlation matrices of ozone, nitrogen dioxides and nephelometry.