A note on smoke concentration in urban Athens,using data measured by two different methods

Summary The relationships between smoke concentrations, measured at two monitoring stations in Athens by the ASTM (American Society for Testing and Materials) and the OECD (Organization for Economic Co-Operation and Development) methods are studied by using a sample of 738 mean daily values of simultaneous measurements during the period 1984–1986. It is shown that an exponential model, different for each monitoring station, with smoke concentrations in COH (coefficient of haze) as the independent variable and smoke concentrations in gr/m³ as the dependent variable, was the most appropriate for transforming smoke data from COH to gr/m³. Also it is shown that the transformation models can be applied independent of the prevailing meteorological conditions. Finally some tentative conclusions are derived concerning the long term variations of smoke concentrations in gr/m³ for the period 1977–1990 and 1973–1990 at the two monitoring stations respectively. The trend analysis has shown that pollution abatement efforts resulted in an about 10% per year decreasing trend in smoke concentrations, during the period 1986–1990, at these two Athenian stations.With 4 Figures